It's all about chemical engineering

Nature vs Nurture (Should We Include Perseverance As 3rd Competitor?)

2013-10-28T12:13:00.003+07:00

Hi, I'm back.

After several months, I want to start sharing with all of you again. This time, I want to start with an article about something that maybe we know it but we just don't "realize" it (at least, I hope YOU already know this before). :D

What is the difference between smart and "dumb" student? Well, maybe I should change "dumb' with "poor performed" because the reality is our believe that someone is born with smarter brain than the other is wrong. Let's start the discussion with our experience. Do you realize this pattern in your past experience?Different kids with different levels of preparation come into a math class. Some of these kids have parents who have drilled them on math from a young age, while others never had that kind of parental input.

On the first few tests, the well-prepared kids get perfect scores, while the unprepared kids get only what they could figure out by winging it—maybe 80 or 85%, a solid B.
The unprepared kids, not realizing that the top scorers were well-prepared, assume that genetic ability was what determined the performance differences. Deciding that they “just aren’t math people,” they don’t try hard in future classes, and fall further behind.
The well-prepared kids, not realizing that the B students were simply unprepared, assume that they are “math people,” and work hard in the future, cementing their advantage.

For almost everyone, believing that you were born dumb—and are doomed to stay that way—is believing a lie. IQ itself can improve with hard work. Because the truth may be hard to believe, here is a set of links about some excellent books to convince you that most people can become smart in many ways, if they work hard enough:

The Art of Learning by Josh Weitzkin

Moonwalking with Einstein by Joshua Foer

The Talent Code by Daniel Coyle

Talent is Overrated by Geoff Colvin

After you read at least one of these book, what do you think about it?
Source: http://qz.com/139453/theres-one-key-difference-between-kids-who-excel-at-math-and-those-who-dont/#!

#randompost: Curse of Knowledge

2013-10-28T12:11:00.001+07:00

"When sharing ideas we have a tendency to slip into jargon. To talk in ways that only insiders can understand. We know so much about the idea that we assume others do as well. So we go into all the nuances and complexity. Without realizing that we’re losing our audience along the way. It’s called the curse of knowledge.KISS – Keep It Simple, Stupid"-Jonah Berger-

PERTANYAAN PERSIAPAN PENDADARAN TEKNIK KIMIA (2)

2012-04-18T22:31:00.001+07:00

1. Alasan pemilihan tangki horisontal pada dekanter :
a. Karena pemilihan fase terpisah hampir sama, sehingga sama besar kalau dihorisontalkan respon LC nya lebih terlihat
b. Mengatasi tekanan hidrostatika.
c. Meminimasi turbulensi

2. Kavitasi : peronggaan yang diakibatkan oleh adanya gas /uap di dalam pompa. Bila pompa sentrifugal beroperasi pada kapasitas yang besar maka tekanan zat cair pada ujung sudu akan menurun. Jika tekanan di bawah P uap zat cairnya (dalam Head) mengakibatkan zat cair tersebut menguap atau membentuk butir-butir air. Sewaktu memasuki sudu, tekanan akan naik sehingga butir tersebut pecah danmenimbulkan suara bising. Proses ini dapat merusak performansi dan pompa itu sendiri.
Cara mengatasi:
a. menurunkan kapasitas
b. mengawasi kondisi cairan pada suction pumpnya.

3. Head pompa : beda tekanan yang dinyatakan dlm tinggi colom cairan

4. Double pipe HE

a. alasan memakai counter current, krn LMTDnya lebih besar, sehingga luas perpindahan panas yang diperlukan kecil, sehingga alat akan kecil.

b. yang masuk inner pipe: korosif; tekanan lebih tinggi; mengandung kotoran.

5. Alasan pemilihan tangki penyimpan yang digunakan berdasarkan :
a. Macam bahan yang disimpan
b. Tekanan atau keadaan vakum yang diinginkan
c. Jumlah yang disimpan

6. Mengapa disimpan dalam bentuk cair? jika disimpan dalam fase gas maka volume semakin besar berarti biaya semakin besar.

7. Mengapa dalam penyimpanan diambil asumsi tangki berisi 80% cairan? karena jika ada cairan yang menguap maka akan mengisi volume 20% yang dikosongkan tersebut (untuk keamanan).

8. Bagaimana cara mengatur agar tekanan didalam tangki tetap pada saat pengisian dan pengosongan? dengan alat vent yi alat yang menjaga agar tekanan didalam tangki tetap pada saat pengisian dan pengosongan.

9. Mengapa tangki penyimpan harus ditutup? karena u/ mencegah kontaminasi ; menghindari api ; zat2 berbahaya

10. Bagaimana kriteria pemilihan jenis pompa?

a. Pompa reciprocating

Tenaga yang diberikan adalah gerakan piston yang menekansistem itu.

Kapasitas pemompaan kecil, tetapi dapat beroperasi pada head yang tinggi

Perawatan lebih sulit

Cocok untuk memompa zat cair yang sangat viscous dan baik untuk operasi pada tekanan

tinggi.

b. Pompa sentrifugal
    Tenaga yang diberikan tenaga sentrifugal
    Kapasitas besar, head yang lebih rendah
    Perawatan mudah
    Cocok untuk memompa zat yang encer (tidak viscous)

    Perlu ruang sedikit
    Harga murah
    Sederhana tidak berisik

11. Apa itu NPSH? absolute pressure pada bagian suction yg dinyatakan dalam feet cairan yg dipompa.

12. Terangkan mengapa fluida yang dipompa tekanannya naik? Jika digunakan pompa sentrifugal, maka perputaran impeller akan menghasilkan gaya sentrifugal yang akan melempar cairan yang ada ke dinding pompa (casing) sehingga zat cair memiliki tenaga kinetis. Tenaga ini dirubah menjadi tenaga tekan sewaktu zat cair meninggalkan impeller.

13. Terangkan cara perancangan pompa?

a. Menentukan kapasitas pompa (debit = Q gpm)
b. Menentukan D pipa dengan mengetahui v = ft/dtk
c. Menentukan jenis pipa dan sistem pemipaan
d. Menghitung fraction head (Re --> F)

e. Menentukan tinggi elevasi
f. Menentukan velocity head v = Δ v2/2lgc
g. Menentukan presure head
h. Menghitung total head dengan Bernoully:

14. Dasar pemilihan silinder tegak/ horisontal
a. Tegak : volume basar ; atmosferis
b. Horisontal : volume kecil ; P> 1 atm ; < 50 atm
c. Tangki Bulat : volume besar ; P≥ 50 atm

15. Dengan adanya LC untuk mengatur ketinggian cairan di dalam reboiler supaya sama dengan tinggi pada dasar menara, agar uap yang terbentuk tidak ke bawah. Cairan turun ke bawah lewat down comer, gas/uap membentuk gelembung-gelembung melewati lubang-lubang perforated, sehingga terjadi transfer massa dari gas ke cairan dan sebaliknya sehingga diperoleh kesetimbangan fase.

16. Proses pemulihan air pendingin di cooling tower:
Air yang sudah digunakan sebagai pendingin suhunya naik dikontakkan dengan udara pada suhu 30 oC, sehingga terjadi transfer panas dari air ke udara, karena udara tidak jenuh maka terjadi trasfer massa dai air ke udara, sehingga suhu air menjadi turun (dingin) dan kelembaban di udara meningkat.

17. Fungsi udara pada Cooling tower : mengalirkan udara ke cooling tower untuk dikontakkan dengan air yang akan dipulihkan.

18. Faktor yang harus diperhatikan dalam pemilihan tangki:
a. Sifat bahan yang disimpan
b. Tegangan yang ditimbulkan
c. Stabilitas elastic

19. Fungsi udara tekan pada setiap kontrol adalah untuk menggerakkan instrument pengendali.

20. Bila luas permukaan perpindahan panas yang tersedia ≥ luas perp.panas yang diperlukan à jacket. Sebaliknya digunakan Coil.

21. Proses pembentukan steam di Boiler : Bahan bakar dan udara masuk pada ruang bakar, air masuk pada shell, uap yang terbentuk berada (masuk pada) tube dan keluar melalui cerobong gas.

22. Proses pembuatan udara tekan : udara lingk ditekan sampai 4 atm dengan kompressor udara yang dilengkapi dengan filter debu. Udara tekanan 4 atm dihilangkan airnya dengan melewatkan pada tangki silika. Kemudian udara yang telah kering ditampung dalam tangki.

23. Return Of Investment (ROI)
yi: Penghasilan untuk mengembalikan modal.
Ini sangat penting dalam perusahaan supaya kita dapat mengetahui kapan modal-modal dapat dikembalikan.
Untuk pabrik Industri Kimia , minimum % ROI yang dapat diterima:
Pabrik yang dinilai resiko rendah = 11%
Pabrik yang resiko tinggi = 44%
Penilaian berdasarkan modal tetap atau modal kerja, keduanya dapat dibenarkan. Prosentase ini dihitung berdasarkan atas dasar sebelum pajak dibayar.

24. Pay Out Time (POT)
yi : waktu untuk mengembalikan modal

POT resiko rendah = 5 tahun
POT resiko tinggi = 2 tahun (Aries & Newton)

25. Depresiasi
Depresiasi tujuannya untuk mengumpulkan dana sehingga bila sudah waktunya membeli alat baru sudah terkumpul uang untuk membeli alat itu.

26. Discounted Cash Flow (DCF)
yi : pengembalian dana terhadap nilai sekarang.
misal : i = a %
Bila didapatkan harga i yang lebih besar dari pada bunga bank maka proyek tersebut mempunyai potensi
DCF ideal 2 – 2,5 %

27. Payroll Overhead (kemahalan)
yi : pengeluaran selain gaji.
Misal : untuk pensiun, liburan, THR, dll.

28. Plant Overhead
yi : pengeluaran biaya untuk service yang tidak dalam unit produksi.
misal : poliklinik dan tempat ibadah.

29. Analisa Break Even
suatu cara untuk mengetahui pada volume produksi berapa perusahaan tersebut akan tidak rugi dan tidak untung. Jadi BEP dapat dipakai untuk evaluasi.

30. Modal tetap adalah modal untuk investasi produksi dan perlengkapannya.
Modal tetap terdiri dari ;
Instalasi alat-alat produksi.
Bangunan alat-alat proses dan alat-alat pembantu untuk menampung bahan produksi.
Pajak
Asuransi
Jalan
Engineering (tenaga ahli)
Untuk mendikrikan plant baru.

31. Modal kerja adalah modal yang benar-benar digunakan untuk ongkos perusahaan.
Modal kerja terdiri dari:
Bahan mentah dalam periode tertentu
Upah buruh
Stock hasil produksi
Uang di kas

32. Capital Investment : modal yang dibutuhkan untuk keperluan fixed capital dan working capital

33. Working capital : modal kerja untuk menjalankan fasilitas produksi dan persediaan bahan baku.

34. Fixed Cost : Jenis biaya yang selama 1 periode harga tetap jumlahnya/ tidak mengalami perubahan.

35. Variabel Cost : Jenis biaya yang naik turun bersama dengan volume kegiatan. Produksi bertambah, bertambah pula biaya variabel.

36. Extended Credit : Barang yang sudah dijual tetapi belum dibayar.

37. Available Cash: Uang tunai yang harus ada di kas untuk gaji pegawai, rekening, service.

38. Finance : uang yang berputar atau biaya yang dikeluarkan untuk membayar orang yang mengurusi masalah keuangan.

39. BEP: Suatu pernyataan bahwa pabrik tepat tidak untung dan tidak rugi.

40. DCF : Bunga maximal ( biasanya setelah pajak) dimana seseorang berani membayar kembali hutang atau pinjaman untuk keperluan membiayai proyek untuk masa servisnya.
Jika DCF < bunga bank lebih baik kita menginvestasikan di bank, karena lebih menguntungkan.
POT : waktu yang dinyatakan dalam tahun dimana uang yang ditanam harus sudah kembali atau masa tahun pengembalian modal investasi dari laba yang dihitung sebelum dikurangi penyusutan.

41. ROI : kemampuan untuk mengembalikan modal atau salah satu cara untuk pernyataan yang umum dipakai untuk menunjukkan hubungan antara laba tahunan yang diperoleh dalam rangka usaha pengembalian modal investasi.

42. Payroll Overhead : Baiya yang dikeluarkan untuk tunjangan pensiun, kematian, cuti, asuransi karyawan, bonus keuntungan.

43. Plant Overhead : Biaya perawatan sebagai fungsi pelayanan secara tidak langsung dengan unit produksi, seperti biaya perawatan kesehatan, sarana ibadah dll.

44. SDP : Suatu tingkatan produksi di bawah BEP yang menunjukkan biaya total dan penjualan total. Pabrik menderita rugi dan harus membayar biaya tetap bila di tutup.

45. Physical Plant Cost (PPC) :
Harga alat sampai di tempat
Instalasi
Pemipaan
Instrumentasi
Isolasi
Tanah dan perbaikan
Bangunan
Alat yang dibuat di tempat
FC = PPC + Construction fee + Contingency

46. Direct Manufacturing Cost (DMC) :
Bahan Baku
Buruh
Supervisi
Maintenance
Plant supplies
Royalities & patent
Utilitas

PERTANYAAN PERSIAPAN PENDADARAN TEKNIK KIMIA

2012-04-18T22:12:00.000+07:00

1. Bunyi dengung keras pada pipa disebabkan :

a. fluktuasi tekanan

b. kavitasi

c. benturan air

d. keadaan yang tidak seimbang pd bagian yang berputar

2. NPSH adalah tekanan yang dibutuhkan pada suction pompa yang lebih tinggi daripada tekanan uap cairan yang dipompa

3. Untuk menentukan sifat2 pipa dapat ditentukan dari Sch NO, sch ini berbeda-beda dan berguna untuk :

a. menahan internal pressure dari aliran

b. kekuatan dari bhn

c. mengatasi karat

d. mengatasi ketegasan pipa

4. Pemilihan pipa yang dipakai untuk aliran zat cair dipengaruhi oleh diameter pipa, kekutan pipa terhadap kondisi operasi, ketahanan pipa terhadap pengaruh korosifitas.

5. Fitting adalah sepotong pipa yg digunakan utk memenuhi kebutuhan pemipaan spt:

a. menyambung 2 pipa:

tanpa merubah arah & diameter = coupling

merubah arah = elbow

merubah diameter = reducing

b. membatasi arus dlm pipa = plug

c. membuat arus bercabang = tees

6. Cara menghitung luas transfer panas, perlu diketahui

a. panas yang ditransfer (Q)

b. overall coeffisien heat transfer (Ud)

c. LMTD

7. Untuk menghitung temperatur drp dipakai LMTD karena beda suhu antara fluida pns & dingin pada waktu masuk & keluar tidak sama, sehingga perlu menentukan nilai rerata dalam pers : Q = Ud.A.LMTD

8. Besar kecilnya ∆P berpengaruh terhadap operasi, karena dipengaruhi oleh faktor friksi yang berbanding lurus terhadap Re, maka jika ∆P >> baffle space dekat, aliran menjadi lambat, perlu tenaga pompa >>. Jika ∆P<<< perpindahan panas tidak sempurna.

9. Kecepatan fluida pada HE dibatasi karena jika tidak, dapat menimbulkan kerak jika mengalir lambat, kotoran & lumpur dapat melekat pada pipa. Selain itu juga agar heat transfer tidak terlalu cepat atau lambat.

10. Shell & tube banyak dipakai pada industri karena :

a. luas permukaan >> sehingga heat transfer >>

b. velocity pada tube >>

c. turbulen >>

11. Fouling faktor adalah faktor yang mempengaruhi permukaan perpindahan panas sebagai akibat :

a. ada endapan pada sistim aliran

b. adanya korosi karena interaksi fluida dengan bahan yang digunakan pada HE

12. Jika Rd < Rd min maka Uc hrs > atau Ud < dengan memperbesar alat. Uc > dengan membesarkan h.

a. hio > dgn menambah jumlah passes atau N

b. ho < dgn memperkecil baffle

13. Untuk mengkontrol/mengetahui apakah HE dapat digunakan adalah Rd > Rd min agar dapat dibersihkan bersamaan dgn HE yg lain, ∆P < ∆P max (10 psi)

14. Peranan kesetimbangan dalam tekim adalah untuk mengetahui reaksi dapat berlangsung atau tdk, hasil maksimal dalam suatu reaksi, mengetahui susunsn zat2 dalam kesetimbangan jika P & T diketahui

15. Konstanta kesetimbangan (k) adalah aktifitas reaktan terhadap produk dalam kesetimbangan

16. Tujuan depresiasi adalah untuk mengumpulkan dana shg bila sudah waktunya membeli alat dana tsb sudah tersedia

17. Analisa BEP adalah suatu cara untuk mengetahui pada volume berapa perusahaan tdk untung & rugi.

a. Jk BEP>>> maka :

- untung = laju produksi >>

- rugi = harga jual <<

sulit mdpt laba

total cost >>

b. Jk BEP <<< maka :

- untung = harga jual >>

Va & Ra <<

- rugi = laju produksi <<

18. Tujuan digunakan alat kontrol adalah agar prose produksi berjalan secara tepat & ekonomis dgn jalan:

a. menurunkan biaya buruh

b. mengurangi human eror

c. mengurangi uk alat proses

d. kemanan lbh t’jg

19. Kontrol adalah penjagaan kondisi proses yg sedang berlangsung agar keadaan tetap sesuai dgn kondisi operasi yg dikehendaki

20. LC = alat yg berfungsi untuk membuat supaya level suatu sistim tetap pada set pointnya (permukaan)

LI = alat yg menunjukkan besarnya ketinggian suatu sistim dimana LI hanya dapat menunjukkan level pada saat terakhir.

TI = alat yg menunjukkan suhu terakhir dimana signal berasal dari termokopel

TC = alat utk mengontrol temperatur

FC = alat utk mengontrol aliran massa

FR = alat utk menentukan jumlah massa yg mengalir

21. Set point adalah harga yg dikehendaki dari kontrol variabel untuk dijaga

22. Humidifikasi adalah proses perpindahan fase cair masuk kedalam campuran gas yg terdiri dari udara & uap air

23. Suhu bola kering adalah suhu campuran uap & gas yg diukur oleh termometer dalam campuran tsb

24. Suhu bola basah adalah suhu kest yg dicapai apabila sejumlah kcl cairan diuapkan kedlm jml bsr camp gas yg tdk jenuh

25. Campuran tdk jenuh adalah jika tekanan parsiil uap dalam campuran gas & uap < dari tekanan uap pd keadaan setimbang dari cairan pd T yg sama

26. Titik embun campuran adalah tekanan parsial uap = tek uap camp

27. Kapasitas panas (Cp) adalah energi untuk menaikkan suhu suatu zat sebanyak 1 °C dimana energi tsb dpt diberikan dgn heat transfer dalam campuran tertentu

28. Psia adalah tekanan absolut dimana tekanan gauge + tek barometer (lbf/in2)

29. Apabila suplai bahan baku terhenti dapat diatasi:

a. apabila hanya 1 bln mk pabrik masih memiliki persediaan&laju produksi < 100%

b. jika berhenti selamanya pabrik juga berhenti krn asumsi saat mendirikan pabrik adalah persediaan bahan baku tdk macet sampai umur ekonomi pabrik

30. Hal2 yg perlu diperhatikan dalam pengagkutan bahan adalah pipa, fitting, valve, pompa alat ukur aliran.

31. Cara menentukan kapasitas volumetri pompa dari tangker ke tangki bahan baku adalah :

a. menentukan volume tangki

b. menentukan waktu pengisian

c. menentukan kapasitas volume pompa

32. Dasar pemasukan bahan baku & hasil ke tangki, dari atas atau bawah adalah :

a. bhn non volatil = dari bagian bawah dgn tujuan agar bahan tercampur scr homogen secara turbulensi, utk mencegah terjadinya endapan pd dasar tangki

b. bhn volatil = masuk dari atas, mencegah terjadinya penguapan scr tiba2. Dimana pada saat menguap tekanan uap akan mengenai bagian atas tangki, jika P >> dapat merusak konstruksi. Adanya penguapan membuat jarak dgn roof makin dekat sehingga roof akan jenuh & mengalami pengembunan. Kedua bahan masuk dari atas & bawah, shg apabila terjdi penguapan akan berkontak dgn bahan dari atas dan tdk membahayakan tangki. Bahan dimasukkan dari atas agar P tetap, kalau dari bawah P berubah2

33. Dasar pemilihan kapasitas produksi adalah dari data BPS. Jika kapasitas dilipatgandakan maka alat tdk dapat beroperasi scr optimal krn pabrik telah dirancang utk kapasitas & kemampuan tertentu

34. Cara mempertahahnkan konversi reaktor adalah dgn mempertahankan kondisi operasi

35. Cara mempertahankan kemurnian produk atas & bawah MD adalah dgn refluk

36. Reboiler berfungsi utk menguapkan cairan. Tdk ada reboliler maka tdk terjadi pemisahan

37. Flooding terjadi bila kec.cairan > kec.uap, akan terjadi weeping dimana cairan akan melewati lubang pd plate

38. Blow up terjadi bila kec.uap > kec.cairan, akan terjadi entrainment dimana butir2 cairan terikut dlm uap

39. Dasar pemilihan MD sieve tray adalah mudah utk membersihkannya, dapat beroperasi pd P >>. Cara mempertahankan kondisi operasi MD adalah dgn mengatur pendinginan & pemanasan di ConDensor & ReBoiler

40. CD = untuk mengembunkan uap, terjadi perubahan fasa

RB = untuk menguapkan cairan, terjadi perubahan fasa

HE = utk memenaskan fluida, terjadi kenaikan suhu

CO = utk mendinginkan fluida, terjadi penurunan suhu

41. Yang terjadi bila ∆P rendah adalah menguntungkan, krn tenaga utk memompa <<

42. Ud adalah koef.transfer panas overall dari suatu fluida dlm keadaan kotor. Ud gas < Ud cairan krn faktor pengotor gas < dari cairan

43. Pompa reciprocating:

a. Kapasitas pemompaan <<, tetapi dpt beroperasi pd head tinggi

b. Perawatan lebih sulit

c. Untuk zat sangat kental & ∆P >>

d. Tenaga yang diberikan adalah gerakan piston yg menekan sistem

e. Fluida tdk kotor

f. Tdk korosif

Pompa centrifugal:

a. Tenaga yg diberikan adalah tenaga centrifugal

b. Kapasitas >>, head rendah

c. Perawatan mudah

d. Untuk memompa zat yg encer, ∆P <<

e. Tdk berisik, harga murah, perlu ruang sedikit

f. Korosif

g. Fluida yg mengalir mengandung kotoran

44. Fluida yg dipompa tekanan naik, jika digunakan pompa centrifugal maka perputaran impeler akan menghasilkan gaya centrifugal & melempar cairan ke dinding pompa shg cairan memiliki tenaga kinetis yd diubah menjadi energi tekan sewaktu cairan meniggalkan impeler.

45. Ex valve adalah alat utk mengubah tekanan pd entalpi tetap

46. Keuntungan digunakan saturated dibandingkan dgn superheated adalah panas/energi saturated > krn adanya panas laten, sedang superheated adalah panas sensible yg tergantung pd ∆T, maka daya pemanasnya <<. Pada saturated jika ingin mengubah P maka T berubah (tertentu). Pd superheated T tdk tergantung P, shg utk P tertentu T dapat bermacam-macam

47. Kerugian RATB adalah reaksi berlangsung pd konsentrasi reaktan yg rendah yaitu = konsentrasi dalm cairan yg meninggalakan reaktor, akibatnya ukuran reaktor menjadi >>. Merupakan proses cair2, supaya homogen harus diaduk.

48. BWG (birmingham wire gage) adalah ukuran tebal tube

49. Dipilih HE counter current krn mempunyai LMTD >>, shg luas transfer << mk ukuran HE <<

50. Alasan memilih kettle reboiler adalah menginginkan kemurnian produk bawah >>, juga tdk memerlukan pompa. Pada tube terjadi kesetimbangan uap & cairan, steam keluar dr atas krn LMTD >> & cairan keluar scr gravitasi

51. Udara tekan berlangsung secara adiabatis, yaitu tdk ada pertukaran panas antara sistem dgn lingkungan

52. Dasar pemilihan :

a. silinder tegak = vol >>, atmosferik

b. silinder horisontal = vol <<, 1 < P < 50 atm

53. Genre dpt digunakan pada siang hari, malam sampai jam 10 mlm, krn menyebabkan polusi suara

54. FC diletakkan setelah kran atau pompa supaya dapat mengontrol aliran shg kebutuhan pd alat berikutnya terpenuhi secara tepat. Jika diletakkan setelah pompa maka aliran setelah kran tdk terkontrol.

55. LC pd reboiler adalah untuk mengatur ketinggian cairan dalam RB supaya = tinggi pada dasar menara agar aliran dapat mengalir dari MD ke RB

56. Pada MD kesetimbangan antara caiaran & uap terjadi saat cairan turun ke bawah lewat down comer, gas atau uap membentuk gelembung2 melewati lubang perforated, shg terjadi transfer massa dari gas ke cairan & sebaliknya maka diperoleh kesetimbangan.

57. Faktor2 yg hrs diperhatikan dalam pemilihan tangki:

a. Sifat bahan yg disimpan

b. Tegangan yg ditimbulkan

c. Stabilitas elastik

Bahan2 tdk berbahaya dapat disimpan pd bak atau tangki. Jika beracun/berbahaya pada tangki tertutup sesuai dgn kondisi operasi. Fluida pada tekanan atmosferik pd tangki vertikal dgn dasar rata & atap eliptical/cone. Tangki terbuka untuk operasi batch/untuk mixer

58. HE tdk dapat merubah P, hanya untuk pertukaran panas

59. Electric conection pd kontrol berfungsi untuk memberikan signal pada alat kontrol

60. ReBoiler berfungsi untuk menguapkan sebagian cairan yg keluar dari bawah MD. Dilengkapi LC agar uap yg terbentuk tdk keluar lewat bawah dgn cara mengatur ketinggian cairan dalam ReBoiler supaya sama tinggi dgn dasar MD, shg jika cairan dari MD > tinggi dari RB, cairan RB akan tumpah melewati weir, sdg cairan yg tdk tumpah diuapkan kembali & dikembalikan ke MD

61. Fungsi udara tekan pd setiap alat kontrol adalah utk menggerakan instrument pengendali

62. Proses p’btkan pd boiler adalah bahan bakar masuk pada furnace, air masuk melalui shell. Uap hasil pembakaran masuk melalui tube & memanaskan air shg dpt terbentuk steam. Kemudian uap tsb keluar melalui cerobong gas

63. Proses pembentukan udara tekan adalah udara ditekan sampai tekanan tertentu & bercampur dgn udara dari kompresor yg dilengkapi dgn filter debu, setelah itu dilewatkan pada tangki silica untuk menghilangkan uap air. Kemudian udara yg telah kering ditampung pd tangki horisontal dgn ukuran kecil, P atmosferik.

64. Royalti adalah membayar sejumlah uang kepada pemilik pabrik krn menggunakan hak cipta orang lain. Patent adalah membeli paten kepada seseorang

65. Pada mixer/flokulator tdk terjadi reaksi krn berlangsungh pada T<< & bahan yg direaksikan adalah anorganik yg bereaksi pd T >>

66. Sifat2 kettle RB adalah heat transfer <<, mhl, kecenderungan mengendapkan kotoran tinggi. Kondisi yg diinginkan adl heat transfer >>, kondisi yg tdk stabil dpt diantisipasi, minimasi cairan yg kluar dr RB, dpt diop dkt dgn tek kritis

67. Head pompa adalah beda tekanan yg dinyatakan dalam tinggi kolom cairan

68. Reaksi berjalan searah bila konstanta kesetimbangan reaksi >>

69. 2 bahan dapat bereaksi krn keduanya mencapai energi aktivasi tertentu pada T & P tertentu.

70. Energi aktivasi adalah energi minimum yg diperlukan untuk berinteraksi antar bahan

71. Pada tangki biasanya hanya terisi 80%, dimaksudkan untuk berjaga2 bila terjadi penguapan, maka uap akan mengisi 20% kapasitas tangki, shg tetap terjaga keamanannya

72. Pompa batch = mempunyai target untuk memenuhi tangki dalam waktu tertentu. Bekerja saat bahan baku tiba atau pengosongan tangki, bekerja sewkt2

Pompa kontinyu = kapasitas sesuai dgn massa yg mengalir

73. T wet bulb pada Cooling Tower adalah suhu terendah adiabatis

74. Guna ventilasi adalah untuk menjaga tekanan di dalam & diluar pada 1 atm

75. Macam2 bentuk roof antara lain elip (volatil), cone (non volatil). Luas permukaan elip > cone, keduanya dapat menahan P >>

76. Buffle = pd shell & tube berfungsi untuk mengendalikan aliran di shell

= pd RB untuk mengendalikan tinggi cairan di dasar menara (weir)

77. Make up di CT berfungsi untuk menambahkan air yg hilang krn menguap

78. Pada sand filter ukuran packing semakin ke bawah diameter makin besar, shg tidak memungkinkan kotoran lolos ke bawah.

79. Blow down di boiler untuk menghilangkan mineral2 yg terlarut dalam air, krn ketika menguap mineral tsb tertinggal di cairan & dopat menimbulkan kerak

80. Pada HE pendingin cairan masuk lewat bawah, krn cairan akan memenuhi rongga bagian atas terlebih dahulu. Sedang pd HE pemanas steam akan masuk lewat atas krn steam akan memenuhi rongga atas terlebih dahulu.

81. Steam pada P >> tdk ekonomis, krn butuh tenaga >> utk memompa

82. Draft pd CT menyebabkan penurunan P shg udara tertarik ke atas

83. Steam pada T > 200°C maka P juga >>, shg digunakan dowterm utk zat2 yg Td >> & P <<

84. ∆T pd setiap plate di MD berbeda

85. Semakin banyak plate pd MD ∆P >>, sangat diperlukan agar terjadi aliran uap dari bawah ke atas, maka semakin ke atas P makin <<

86. HE dapat dipakai cocurrent, tetapi LMTD <<. Umpan masuk & pendingin/pemanas sama2 mengalami perubahan T, tdk efisien (hubungan dgn Q)

87. Macam2 tangki:

a. Tangki terbuka = tangki pencpr

= tangki pengendap

b. Tangki silinder tertutup = penyimpan pd 1 atm

c. Tangki silider horisontal = penyimpan > 1 atm

d. Tangki bola = P >>, sgt volatil

88. Fluida dgn Td < 30°C disimpan dalam keadaan cair krn untuk bahan yg sama ρ cair > ρ gas, shg dgn massa yg sama vol << jika disimpan dalam bentuk cair dgn P >> atau ditambah refrigerant. Lebih ekonomis

89. Pemasangan LI jika tangki sangat tinggi adalah dgn memasang manoneter pd dasar tangki. P = ρ g h ..... maka ketinggian dapat diketahui

90. Tangki harus tertutup dgn pertimbangan2 :

a. Menghindari kontaminasi

b. Adanya penguapan

c. Mencemari lingkungan

91. Untuk menghindari kotoran mengendap pada permuk pipa, maka bahan yg diuapkan max 80% dari total aliran masuk. Kelebihannya bergabung dgn zat cair yg akan masuk

92. Pada utilitas harus dicegah terbentuknya foam. Foam adalah butir gelembung gas pada permukaan air pada boiler akibat adanya kontaminasi dgn minyak pada air umpan boiler. Akumulasi gas H2 yg berlebih krn jumlah blow down kurang & treatment yg berlebih dapat menimbulkan foam

93. Dipilih konstruksi menggunakan carbon steel :

a. Struktur kuat

b. Kondisi operasi atmosferik

c. Harga murah

d. Tahan korosi

94. Pompa adalah alat untuk memindahkan/mengalirkan fluida dari 1 tempat ke tempat lain

95. Head adalah tenaga yg dibutuhkan untuk mengalirkan fluida yg dinyatakan dgn satuan panjang

96. Rake adalah alat pada clarifier yg berfungsi untuk menggeruk endapan pada bagian bawah dgn kecepatan rendah

97. Pada sand filter semakin sering dipakai endapan yg terbentuk semakin banyak, ∆P >> maka diperlukan pencucian scr berkala

98. Fire Tube Bolier (FTB) = steam saturated, kapasitas <<, P <<

Water Tube Boiler (WTB) = steam super & satur, kap >>, P >>

99. Pada CT air melepaskan panas krn air berubah menjadi uap, pst ada panas yg dilepas shg air menjadi dingin. Panas yg mengubah air menjadi uap adalah panas laten. Antara air & udara terjadi transfer panas & massa, udara mengandung air dalam jumlah sedikit akan terikut ke udara

100. Semakin banyak pass maka pressure drop >>, tenaga untuk memompa >>, sulit dilakukan pembersihan krn banyak pipa belok

Catatan Program Fasttrack 3: Ide Thesis Takut Dijiplak?!

2012-04-07T21:43:00.000+07:00

Tiba-tiba saya ingin menulis tentang topik ini karena beberapa kali hal ini mencuat di benak saya dan teman-teman. Topik ini mlai memanas saat briefing seminar online dan kami diminta memaparkan rancangan thesis kami. Secara spontan, beberapa teman yang kritis mengeluarkan pendapat "bagaimana jika kita menceritakan rancangan thesis kita dan nanti dijiplak oleh orang lain?". Saya sangat dapat memahami pernyataan tersebut. Tujuan dari seminar online adalah untuk saling berbagi ilmu, tapi jika menyangkut ide, apalagi ide yang dibawa adalah baru, fenomenal, atau kreatif yang berpotensi menjadi penemuan baru, tentu kita pasti akan sangat berhati-hati saat share ide tersebut. Apalagi peserta program fasttrack adalah mahasiswa dengan IP S1 yang tinggi (yang saya anggap merupakan calon penemu semua) dari seluruh Indonesia. Akhirnya, dari seminar online yang saya hadiri, semua teman-teman tidak membawa rancangan thesis melainkan hasil tugas akhir mereka.

Masalah tentang "kerahasiaan" ini kembali mencuat setelah beberapa saat lalu saya dan teman-teman menerima e-mail dari UGM yang intinya adalah agar mengirim abstract thesis sebanyak 4 lembar untuk dikirimkan ke Jerman. Tujuannya sangat mulia, yaitu agar pihak Jerman yang membaca ide berlian kami akan tertarik untuk merekrut kami sekolah di Jerman secara gratis (a.k.a dapat beassiwa S3 di Jerman). Sejak awal memang program fasttrack adalah bagian dari debtswap Indonesia dengan pihak Jerman. Tapi sekali lagi, jika ide yang diminta, tentu akan menimbulkan kontroversi, apalagi kali ini kita tidak tahu akan diberikan ke pihak Jerman mana saja ide kita ini. Hmmm... Akankah masalah ini mencuat lagi ke depannya selama program fasttrack? :p

Catatan Program Fasttrack 2: Administrasi... administrasi...

2012-04-07T21:28:00.000+07:00

Menyambung cerita dari Catatan Program Fasttrack 1, di mana di sela-sela presentasi online kembali ditegaskannya kewajiban mahasiswa peserta program fasttrack untuk melakukan ISR (Intellectual Social Reaponsibility) dalam bentuk mengajar baik di SMA/SMK atau menjadi asisten dosen. Saya kagum dengan komitmen Pak Agus, Pak Nur, dan Pak Jaslin. Selama ini saya sebenarnya ingin melakukan ISR (tentunya jika sudah menerima hak kita=beasiswa S2, sangatlah tidak pantas klo tidak melakukan kewajiban kita, salah satunya melakukan ISR), tapi seperti yang teman-teman fasttrack lainnya, saya tidak tahu prosedur agar dapat mengajar di SMA.

Semuanya bermula dan berakhir di "administrasi". Awal permasalahan "administrasi": untuk mengajar di SMA tentu butuh ijin=surat ijin, tapi kita tidak tahu untuk mendapat surat ijin ini saya harus ke mana/menghubungi siapa (UGM? Seamolec? Dikti? Diknas?). Saya senang karena respons beliau bertiga sangatlah cepat terhadap hal ini. Hanya beberapa hari setelah seminar online pertama, mahasiswa fasttrack UGM mendapat e-mail tentang cara mengajukan surat ijin ISR. Prosedurnya pun sangat mudah, dalam beberapa menit saya dan teman-teman dapat memperoleh surat ijin ISR dari UGM beserta copy surat kewajiban melakukan ISR dari Kemendiknas dan daftar peserta program fastrack sebagai lampirannya.

Selasa, tanggal 3 April saya dan teman saya (Yano dan Galuh) mengajukan surat tersebut ke salah satu SMA negeri di Kota Yogyakarta. Dua hari kemudian, kami datang lagi ke SMA tersebut untuk menanyakan respons dari pihak sekolah. Ternyata respons dari pihak sekolah tidak terlalu positif. pada intinya sekolah mempertanyakan kelengkapan surat kami. Pihak sekolah berkata bahwa di antara surat tersebut tidak ada surat yang menyatakan bahwa Diknas (tingkat Kota atau Provinsi) memberikan "ijin" bahwa sekolah mereka akan "dimasuki" mahasiswa fasttrack dan dijadikan lokasi ISR. Menurut saya pribadi, adanya surat edaran dari Kemendiknas tentang kewajiban kami mengajar di SMA sudah mewakili hal tersebut, tapi rupanya pihak sekolah merasa itu tidak cukup. Pihak sekolah merasa tidak adanya surat secara spesifik dri Diknas kepada sekolah tersebut tidak cukup kuat untuk dijadikan dasar bahwa kami bisa mengajar di sana, karena pihak sekolah tidak ingin mendapatkan masalah jika ada keluhan dari orang tua siswa jika tiba-tiba ada tambahan pelajaran dari mahasiswa/mahasiswa mengajar di kelas formal tanpa disertai surat tadi. Pihak sekolah baru berani menerima kami mengajar di sana jika ada lampiran surat tugas dari pihak Diknas Provinsi/Kota. --- berakhir di masalah "administrasi" (lagi).

Hmmm... Saya dan teman-teman segera ingin menyelesaikan masalah itu hari itu juga. Setelah bolak-balik berbagai gedung UGM mencari pihak yang berwenang tapi akhirnya nasib tidak mengijinkan, akhirnya saya mengirim e-mail ke pihak UGM mengenai masalah ini. Melalui e-mail, UGM akan berusaha membantu menyelesaikan masalah ini. Semoga usaha ini akan segera membuahkan hasil. (apakah UGM bisa meminta Diknas mengeluarkan surat itu atau tidak), dan semoga tidak malah menggantung di sini saja nasib ISR kami.

Saat ini memasuki pertengahan bulan April, dan tahun ajaran berakhir di pertengahan bulan Juni. Tentunya jika kami ingin mengajar di SMA hanyalah mungkin sebelum ujian kenaikan kelas (sebelum bulan Juni). Opsi untuk mengajar sebagai asisten dosen juga tertutup karena di jurusan saya, mahasiswa hanya bisa menjadi grader/asisten lab, dan asisten dosen adalah dosen muda. Semoga yang terbaik yang terjadi... dan saya harap hal itu adalah keluarnya surat dari Diknas sesegera mungkin.

Why Natural Gas Is Cheap and Gasoline Isn't

2012-04-05T05:07:00.000+07:00

THE price of gas has risen rapidly this year

The price of gas has fallen to the lowest level in a decade.

Both of those statements are true. The first refers to gasoline, the second to natural gas.

As the accompanying charts indicate, never in the two decades that natural gas and oil futures have traded have their prices diverged as much as they have now. On an energy equivalent basis, oil costs more than eight times as much as natural gas.

This week, the price of a million B.T.U.’s of natural gas fell below $2.20 for the first time since 2002, while oil prices slipped a little but remained above $100 a barrel. The last time natural gas was this inexpensive, oil cost about $20 a barrel.

The diverging prices reflect the fact that while oil and natural gas can substitute for each other in some uses, the markets for the two products are very different.

Crude oil is a relatively efficient international market, in which the product moves around the globe in tankers that can be diverted from one destination to another almost instantaneously in response to shifts in demand. A sharp change in demand or supply in any region of the globe is likely to show up in prices everywhere.

Oil prices can also be affected by geopolitical concerns well before actual events take place. These days, it appears that oil prices have been pushed up by worries that Israel might attack Iran, leading to a drastic reduction in Iranian oil exports.

The natural gas market, on the other hand, is not a global one. There is a limited trade in liquefied natural gas, which can be transported in tankers, but mostly natural gas must move in pipelines over land. Natural gas prices have been rising in Britain this year even as they have been falling in the United States.

Supply has soared in the United States because of increased production from hydraulic fracturing, but demand cannot change rapidly. Power plants that can burn natural gas or oil were shifted to gas long ago. Add in a relatively mild winter in the United States, which reduced demand, and there appears to have been a glut.

There are efforts being made to use more natural gas. Some fleet vehicles, like buses, already use natural gas, but that market is limited to vehicles that can return to their headquarters for refilling. Chrysler has announced a pickup truck that will run on both gasoline and natural gas, but plans to offer it only to such fleets.

The state of Alaska is also seeking a pipeline that would take natural gas from the North Slope to an Alaskan port, where it could be liquefied and shipped to Asia. The state announced an agreement with Exxon Mobil, BP and ConocoPhillips relating to that project on Friday, but many details remain to be worked out.

Two of the charts show trends in prices of gasoline and natural gas since the end of 2007, when the United States entered recession. At first, reduced economic activity led to reductions in the prices of both products. But the trends began to diverge in 2009. Now, gasoline costs about 30 percent more than it did in 2007, while natural gas costs around 70 percent less.

For what it is worth, which may not be very much, futures traders think that the gap in prices will diminish but remain large. A year from now, oil prices are expected to be almost exactly where they are now, while natural gas prices are forecast to have risen more than 50 percent. If that happens, on an energy equivalent basis, crude oil will still be more than five times as expensive as natural gas.

Source:
Floyd Norris comments on finance and the economy at nytimes.com/economix.

Catatan Program Fasttrack 1: Seminar Online Pertama

2012-03-27T19:09:00.001+07:00

Hari ini untuk pertama kalinya mahasiswa fasttrack dari seluruh Indonesia (UGM, UI, ITB, Undip) melakukan seminar online. Walaupun agak sebal di awal, karena pemberitahuan tentang teknis pelaksanaan seminar online hari ini baru diberikan kemarin siang jam 1 siang, hal ini tetap harus dijalani sebagai bagian dari rangkaian program fasttrack. Secara pribadi, saya mendukung penuh rangkaian program ini, baik konsep pemberian beasiswa kuliah s2 sejak mahasiswa menjalani semester 7 di program s1 nya, kewajiban melakukan ISR (Intellectual Social Responsibility) berupa mengajar di SMA/SMK, membuat blog, sampai kewajiban melakukan seminar (seperti seminar online hari ini). Mungkin beberapa teman ada yang masih mengeluh, tapi saya tahu benar kalau semua ini dibuat demi kebaikan kita sendiri.

Seminar online hari ini dimulai pk 8.30 pagi. Jujur saja, konsep seminar online yang pertama ini kurang jelas. Tidak adanya daftar pemateri sampai acara yang tidak sesuai dengan jadwal masih terjadi. Saya tidak mengikuti seminar online dari pagi hari baik melalui website www.seamolec.org/ft maupun menonton langsung di lantai 2 Gedung MST UGM. Alasan saya cuma karena saya ada kuliah dan kegiatan lain yang lebih dulu sudah saya sanggupi. Sekitar jam 11 siang saya melihat lewat website seamolec, dan masih ada beberapa kendala teknis untuk streaming langsung. Walaupun demikian, saya salut dengan ide seminar online ini. Saya lebih setuju bahwa mahasiswa dibebaskan untuk menonton seminar dari manapun karena toh tidak semua topik yang diseminarkan akan menarik perhatian semua orang.

Saya datang ke gedung MST pk 12.30 untuk persiapan seminar online pk 13.55. tetapi ternyata pk 13.00 tiba-tiba seminar online di UGM ditunda untuk sementara waktu karena ada penjelasan dari Pak Jaslin dan Pak Agus tentang program fasttrack. Thank's God! Baru saja semalam saya email pihak seamolec mengenai kejelasan program ini. Saya kurang tahu di mana hambatannya sehingga UGM terkesan selalu tertinggal dalam berbagai informasi mengenai program fasttrack (seperti tentang teknis seminar online hari ini, teknis mengajar di SMA, banyaknya biaya s2 yang diperoleh, dll). Pertemua siang ini cukup memberi kejelasan dan kepastian mengenai ISR. Setelah dijelaskan dan dipastikan bentuk ISR dan prosedur monitornya tentu pihak mahasiswa akan lebih mudah untuk melaksanakannya (dan pihak penyelenggara dapat menetapkan punishment jika aturan yang telah jelas dilanggar). Memang akhirnya saya tidak jadi seminar online karena tidak cukupnya waktu. Hmmm,,, mungkin kesempatan berikutnya baru kesempatan bagi saya. Pada saat tulisan ini dibuat saya masih berusaha mengakses situs seamolec untuk melihat-lihat hasil seminar online dari Universitas lain, tapi websitenya tidak bisa terbuka juga. *semoga tidak terjadi masalah yang serius di web ini. Haha.

Brief Overview of Heat Exchanger

2012-03-08T17:54:00.000+07:00

n the chemical processing industry, there are numerous types of heat exchanger devices. The types of exchangers can be classified by the duty that they perform, surface compactness, construction features, flow arrangements, and others. In general, a heat exchanger can fall into one of these processing categories:

1. No Phase Change

Liquid to Liquid heat transfer
Liquid to Gas heat transfer
Gas to Gas heat transfer

Phase Change

Condensing a vapor with a liquid or gas service fluid
Vaporizing a liquid with a liquid, gas, or condensing fluid

Heat exchangers can also be broken down into the following two types of mechanical geometries:

Shell and Tube Heat Exchangers
Compact and Extended Surface Heat Exchangers

Approximately 70-80% of the heat exchanger market is dominated by the shell and tube type heat exchanger. It is largely favored due to its long performance history, relative simplicity, and its wide temperature and pressure design ranges. We will explore this technology in further detail later.
The second category mentioned, compact and extended surface heat exchangers, play a smaller role in the chemical processing industry. Some of the available technologies that fit into this category are the plate and frame heat exchanger, finned tube heat exchangers, spiral heat exchangers, fin-fan heat exchangers, and many others.

Compact Heat Exchanger Technologies

The plate exchanger, shown below, consists of corrugated plates assembled into a frame. The hot fluid flows in one direction in alternating channels while the cold fluid flows in true countercurrent flow in the opposite alternating channels. The fluids are directed into their proper channels either by a rubber gasket or a weld depending on the type of exchanger chosen.

Traditionally, plate and frame exchangers have been used almost exclusively for liquid to liquid heat transfer. Today, many variations of the plate technology have proven useful in applications where a phase change occurs as well. This includes condensing duties as well as vaporization duties. Plate heat exchangers are best known for having overall heat transfer coefficients (U-values) in excess of 3-5 times the U-value in a shell and tube designed for the same service.
Plate exchangers can be especially attractive when more expensive materials of construction are required. The significantly higher U-value results in far less area for a given application, thus a lower purchased and installed cost due to its relatively small size. The higher U-values are gained by inducing extremely high wall shear on the plate surface. The best way to think of a plate heat exchanger is that it is essentially a static mixer that happens to transfer heat very well. The plate exchanger, by virtue of its high wall shear stress also minimizes fouling very well.

Typical plate thicknesses range from 0.40 mm to 0.60 mm and passage channel openings can range from 1.5 mm up to 11.0 mm depending on the application and required design pressure (the larger the opening, the lower the design pressure available). These small passages also restrict the size of solids that can be successfully passed through the exchanger.

Perhaps the biggest advantage of the plate and frame heat exchanger, and a situation where it is most often used, is when the heat transfer application calls for the cold side fluid to exit the exchanger at a temperature significantly higher than the hot side fluid exit temperature. This situation is best explained with another set of T-Q diagrams:

Duty 1 shown above is easily accomplished in a single and tube heat exchanger.

Duty 2 shows a severe "temperature cross" or the cold side fluid exiting higher than the hot side fluid. This would require several shell and tube exchangers in series due to the lack of purely counter-current flow. On the other hand, this duty is easily accomplished in a single plate and frame heat exchanger.

Finned Tube Heat Exchanger

Finned tube heat exchangers are commonly used to transfer heat between a gas and liquid. The tubes used in these units are equipped with fins that extend outward from the tubes as shown in Figure 10.

The fins on the tubes allow for a much larger surface area to be packed into a small volume. This is especially important when transferring heat to or from a gas as gasses have extremely low heat transfer coefficients (meaning that large amounts of area are required).

Fin Fan Heat Exchanger

Fin-fan heat exchangers are designed to use air to cool process fluids. Think of them as a giant radiator. The process fluid is passed through the coils and a fan helps pull air over the outside surface to promote cooling. These units again must provide a very large surface area to make up for the poor heat transfer of the air.

Shell and Tube Heat Exchanger

Shell and tube heat exchangers are known as the work-horse of the chemical process industry when it comes to transferring heat. These devices are available in a wide range of configurations as defined by the Tubular Exchanger Manufacturers Association (TEMA, www.tema.org). In essence, a shell and tube exchanger is a pressure vessel with many tubes inside of it. One process fluids flows through the tubes of the exchanger while the other flows outside of the tubes within the shell. The tube side and shell side fluids are separated by a tube sheet.

The shell and tube type is usually indicated as a three (3) letter code from the TEMA specifications as shown in figure below.
The shell side of a shell and tube exchanger usually contains baffles as shown above to direct the shell side flow around the tubes to enhance heat transfer. As you can see, shell and tube exchangers can be configured for liquid-liquid, gas-liquid, condensing, or vaporizing heat transfer.

The tubes can be a different material than shell and the shell can either be cladded or of solid construction. It's impossible to go over all of the mechanical details of the shell and tube here, but this should provide you with a general overview of the construction. There are numerous other sources of information freely available on these types of units.

The tubes and shell can be designed for a variety of design temperatures and pressures. The thermal design of shell and tube heat exchangers is often performed by vendors. The process engineer generally completes a TEMA specification sheet and submits it to vendors for bids. If you're interested in more details on the thermal design aspects of shell and tube heat exchangers, you can visit Wolverine Engineering's website at:
http://www.wlv.com/p...ok/databook.pdf

Understanding the basics of industrial heat transfer will help you better understand opportunities for cost savings in your plant. With energy prices showing no sign of declining, a good basis in heat transfer will help you calculate just how much you can save by installing a new heat exchanger in your plant. With the use a T-Q diagram and a basic understanding of the equipment available to you, making the right choice in heat transfer equipment can yield results for years to come.

Source:

www.cheresources.com

Heat Exchanger Equation

2012-03-08T16:55:00.000+07:00

If we take a closer look at the heat exchanger equation, it's worth noting some assumptions that are made in its derivation. First, the overall heat transfer coefficient and the specific heat (also called heat capacity) of the fluids are assumed to remain constant through the heat exchanger.
If we look at the change in the heat capacity of water, for example, over a reasonable temperature range, here is what we find:

Specific heat of water at 100 °F and atmospheric pressure = 0.9979 Btu / lb °F
Specific heat of water at 210 °F and atmospheric pressure = 1.0066 Btu / lb °F

So, we can see that this is a fairly reasonable assumption for water and it remains reasonable for most industrial fluids. The specific heat of a substance is defined as the amount of heat required to raise the temperature of one pound of the substance by a single degree Fahrenheit (other units can apply as well).

The overall heat transfer coefficient is a calculated variable based on the physical properties of the fluids involved in the heat transfer (hot and cold) as well as the geometry and type of heat exchanger to be used. We'll examine this closer a little later.
The log mean temperature difference or LMTD is used to describe the average temperature difference throughout the exchanger. The difference between the temperatures of the fluids provides the "driving force" for the heat transfer to occur. The larger the temperature difference, the smaller the required heat exchanger and vice versa.
You'll notice from our T-Q diagram used to explain the equations:

that it appears that the temperature difference between the fluids remains almost constant throughout the heat exchanger. This is rarely the case. Let's look at a more practical example. Let's assume that a process stream containing water at 200 °F is to be cooled to 150 °F using cooling tower water available at 85 °F. It is common practice in industry to return cooling tower no higher than 120 °F. In other words, the cooling tower water flow must be such that its outlet temperature from the heat exchanger is less than 120 °F. The reason for this is that cooling tower water often contains treatment chemicals that can plate out onto heat transfer surfaces and cause severe fouling or degradation of the heat transfer rate at elevated temperatures.
Here is what the T-Q diagram may look like for our example case:

You can see that the temperature difference between the two streams will vary widely. This is why the log mean temperature difference is used.Here is how the log mean temperature difference works:

So, for a heat exchanger as described above, we calculate the LMTD as follows:

There can be special cases where the LMTD equation shown above is not applicable. Consider the case below:

If you tried apply the LMTD equation to this special case, you'd find that the result would be zero. In this case the LMTD is the same as the temperature difference on each "end" of the heat exchanger, or 100 °F.

A Brief Word on Flow Direction

Notice that up to this point, the two fluids considered in a heat exchanger have been moving in opposite directions to one another. This is known as counter-current flow. This is the predominantly preferred flow direction because it results in higher temperature difference driving forces within the heat exchanger, thus minimizing the heat transfer area required.
The other flow configuration, where the fluids flow in the same direction, is called co-current flow. Co-current flow, while it is rarely used, does have the advantage of lowering the heat exchanger wall temperature on the hot side fluid. This can be useful for temperature sensitive fluids or as a means of minimizing deposits that are temperature sensitive.

The Temperature Correction Factor, f

The temperature correction factor, f, is used to correct the log mean temperature difference for heat exchangers than lack truly counter-current flow. Many different heat transfer technologies lack truly counter-current flow patterns as a result of their inherent mechanical design. Generally, the value for f should be between 0.75 of 0.97. There are cases when this value can be taken as one, but only if the flow in the exchanger is purely counter-current. There are countless charts available to look up the temperature correction factor for a given configuration.

The Overall Heat Transfer Coefficient

The overall heat transfer coefficient describes the rate of heat transfer in the heat exchanger. Generically, it is described by the following equation:

Where:
U = overall heat transfer coefficient (Btu / h ft² °F)
h_H = hot side heat transfer coefficient
h_C = cold side heat transfer coefficient
Delta x = exchanger wall thickness
k = exchanger wall material thermal conductivity
R_f = fouling coefficient (h ft² °F / Btu)
The equation for the overall heat transfer coefficient is often reduced to the following:

Because the term Delta x / k seldom has any significant impact on the overall U-value.
The overall heat transfer coefficient can either be calculated, looked up in reference materials for a given duty, estimated from past plant experience, or supplied by a heat exchanger vendor.

Source:

www.cheresources.com

Basics of Industrial Heat Transfer

2012-03-08T16:38:00.002+07:00

Heat transfer is one of the most important industrial processes. Throughout any industrial facility, heat must be added, removed, or moved from one process stream to another. Understanding the basics of the heart of this operation is key to any engineers' mastery of the subject.

There are three basic types of heat transfer: conduction, convection, and radiation. The two most common forms encountered in the chemical processing industry are conduction and convection. This course will focus on these key types of heat transfer.

In theory, the heat given up by the hot fluid is never exactly equal to the heat gained by the cold fluid due to environmental heat losses. In practice, however, they are generally assumed to be equal to simplify the calculations involved. Any environmental losses are generally minimized with insulation of equipment and piping.

Any overall energy balance starts with the following equations:

Where:

Q = heat transferred in thermal unit per time (Btu/h or kW)
M = mass flow rate
T = temperature
Cp = heat capacity or specific heat of fluid
Subscript "H" = hot fluid
Subscript "C" = cold fluid
When examining industrial systems, it is common practice to use a graphical form of these equations know as "T-Q diagrams" to enhance understanding and to make sure that the Second Law of Thermodynamics is not disobeyed. In other words, heat can only move from a higher to a lower temperature fluid. Here is how the generic diagram is constructed:

Figure 1: Correct Example of a T-Q Diagram

Figure 2: Incorrect Example of a T-Q Diagram

It's easy to see how viewing a particular heat transfer problem in this way is extremely valuable.
Now that's we've seen how heat moves from a hot fluid to a cold fluid, let's examine the third basic equation that is used to govern the equipment used for transferring heat.
The "Heat Exchanger Equation" takes the form:

Where:
Q = heat transferred in thermal unit per time (Btu/h)
f = temperature correction factor
U = overall heat transfer coefficient (Btu/h ft² °F)
A = heat transfer area (ft²)
LMTD = log mean temperature difference
These three (3) equations are the basis for virtually all heat exchanger design.

Source:

http://www.cheresources.com

Interesting Facts About Wood Furnaces

2012-03-07T16:23:00.000+07:00

Wood furnaces are direct fire heaters. It is a convenient and economical way of heating homes. Many Americans, Europeans, Canadians and people from other countries who experience very cold weather or climate use this kind of unit.
Many users nowadays prefer using wood furnaces to save the Earth from greenhouse effect. Burning bio-mass fuels does not increase the risk of carbon dioxide in the atmosphere. Since wood is a renewable resource safe for the environment, it can also conserve energy.
There are three main types of wood furnaces. First is the Central Wood Furnaces. It can be installed inside the house, garage, mechanical room or at the basement. It uses either a type of forced-air or hot-water system to distribute heat throughout the house.
The second type is the Multi-Fuel Furnaces. This unit can be placed inside or outside the house. It enables the burning of different kinds of fuel like coal, oil, gas and wood. These types are flexible that can work as a back-up option, especially when using other kinds of fuel. It is appropriate in cases where there is only one chimney outlet available. The machine allows venting of the wood as well as the fossil fuel so as to exhaust-up the same pipe.
The third type is the Outdoor Furnace or Boilers. This unit utilizes firewood, particularly when there is a huge supply. It keeps the smoke, mess and bugs outside. The furnace is similar to a small utility building. It is a wood burning furnace placed outdoors. It can be found along the yard, between 50 and 150 feet away from the house.
The furnace firebox is surrounded by a water jacket. As heat is released, it is transferred from the fire onto the water. It is then pumped through insulated pipes and placed underground, then into your house. Finally, heat radiates to warm up the entire house.
On the downside, this unit needs some boots, gloves and a cap to slog out onto the blowing snow to keep it going. Many outdoor boilers are hard to control for a clean burn due to their oversized firebox. Aside from this, it tends to smoke a lot during automatic restart after a long off cycle.
All these wood furnaces are controlled by a thermostat similar to other heating systems. Different heating systems are used on working on these types.
The forced hot-air systems use heat exchangers. The warm air spreads out with ductwork. Burning fuel causes the heat exchanger to heat-up. However, there is no heat storage capacity in this system. The unit needs to be re-fueled everyday to maintain its temperature during the cold months. It is also easy to add filtration, air-conditioning and humidification because the air in this system is being re-circulated. Hydro-air units use ductworks to help distribute air similar to forced hot-air systems. The heat exchanger is replaced by a hot water coil being heated by a hot water loop from its boiler. There are multiple hydro-air units that can be fed by a single boiler throughout the sections of the house for different cool zones. This kind of system is always combined with air-conditioning.
A combination central-heating unit system is designed to burn wood, oil or gas. It relies on the back-up fuel when the wood is not convenient for usage. Both combustion chambers can be maximized with this design. The two fuels are not usually used simultaneously. It can either be hot-air or hot-water furnaces. The disadvantage of this unit is that it tends to be twice as expensive as a single-fuel heater. This dual system offer maximum fueling flexibility.
Wood furnaces have disadvantages also. Some needs to be refueled several times and are a bit dirty to operate. It is also not always convenient to gather fire woods. And to produce good heat, you must know how to stack these pieces of wood properly. Lastly, all these units require electricity due to its thermostat.

Source:
heatexchanger.blogspot.com

Chemical Engineer Salary

2012-03-06T21:14:00.001+07:00

Salary Overview

There are a number of different statistics and estimates for the projected annual salary of someone employed as a chemical engineer in the United States. According to statistics provided by the Bureau of Labor, there are approximately 29,000 chemical engineers working in the country, and the mean annual wage is $91,670. The middle 50 percent of people employed as chemical engineers obtain an annual wage of $88,280 with an hourly wage of $42.44. The lowest 10 percent obtain an annual wage of $56,090 with an hourly wage of $26.97, while the highest 10 percent obtain an annual wage of $132,980 with an hourly wage of $63.93. The industries with the highest employment rates in chemical engineering are architectural engineering, basic chemical manufacturing, and scientific research and development areas. The highest paying industries for chemical engineering involve oil and gas extraction, management, technical, and scientific consulting, and motor vehicle part manufacturing.

Job Description and Outlook

The job of a chemical engineer is to use different principles, concepts, and theories related to chemistry and engineering to solve novel problems that involve how chemicals may be produced or used or combined with other products. Chemical engineers may be involved in a number of processes in chemical manufacturing, such as designing equipment and procedures, or planning and testing methods involved in products and byproducts. They are also likely to be involved in supervising the production of items manufactured through the manipulations of chemicals and plastics. Chemical engineers may also work in a number of industries related to manufacturing besides chemical manufacturing, such as industries involved in the production of electronics, energy (in particular, oil and gas), food, paper, and clothing. Chemical engineers can also find employment in health care, education, and bio technology.

The outlook for chemical engineering as a profession in the United States is healthy; the profession is projected to grow on a rate comparable to the average growth rate of most professions; however, the specific growth rate will vary by the specialty of chemical engineering an individual works in. Chemical engineers involved in the chemical manufacturing industry may actually face a slight decline in employment opportunities over the coming decade, although there will continue to be a number of chemical companies that employ chemical engineers for research and development purposes. Chemical engineers will continue to be in demand in applications and industries involving energy, particularly the industries involved with extraction and refinement of oil and natural gas from the world’s oceans. There will also be a need for engineers versed in safety practices to reduce the likelihood of disasters occurring from industrial incidents, such as oil spills and chemical fires and explosions. There is also expected to be employment growth for chemical engineers who participate in industries related to the provision of services, such as technical services, scientific services, and professional services. The fields of nano technology and bio technology are in rapid development, and chemical engineers will likely be able to seek employment in these fields due to their credentials in engineering and expertise in the manipulation of chemicals and related products.

Training and Education Requirements

The typical terminal requirement in most areas of employment for a potential chemical engineer is a doctoral degree. There are some areas and fields where it may be possible to find employment without a terminal degree, such as in the Federal Government, but the default expectation is for candidates to have completed their education with a Ph.D., and in certain sub industries, having real life work experience is also desirable.

It is possible in many cases to work with a bachelor’s degree in supportive roles as a chemical engineer, depending on the setting and the needs of the employer. In fact, chemical engineers earn among the highest starting salaries of any workers with bachelor’s degrees, and chemical engineers who obtain experience in petroleum engineering may be able to negotiate higher salaries and more opportunities without much trouble. Many employers will pay their employees to further their education.

Certifications

It is usually not necessary to obtain certification to begin working as a chemical engineer. However, there can be benefits to seeking voluntary certification from different professional organizations, such as higher salaries within current locations of employment and access to more lucrative employment opportunities. There are a number of professional associations and organizations from which certification as a chemical engineer may be obtained. The specific requirements for obtaining certification as a chemical engineer will vary from one association to the next. Many organizations request a particular amount of formalized education and post doctorate work, while others are more interested in years of work experience. Still others may ask for a combination of work experience and degrees accumulated through formal education and schooling.

Professional Associations

There are a number of organizations and associations in the chemical engineering industry that offer certification to chemical engineers.

The American Chemical Society
The American Institute of Chemical Engineers
The Electrochemical Society
The National Organization for the Professional Advancement of Black Chemists and Chemical Engineers
The American Hydrogen Association
The Association of Energy Engineers

Source:
www.highersalary.com

How Long Will Our Earth Provide Us With The Oil We Need??

2012-03-06T21:10:00.000+07:00

The Oil and Gas Industry is doing well. As everyone knows, the price for oil has gone up significantly over the last years. Within every kind of market, the price is set and set by the supply and demand balance. At the moment countries such as India and China are booming markets. Their economies are growing with big numbers every year. As their economy continues to grow, so does the demand for gas and oil. This also means that the production facilities must expand. The current consumption of oil in the world is nearly equivalent to the total amount of production facilities- and for this reason relatively small events in the world can have a big impact on the oil price at the moment. Wars and other major events such as hurricane Katrina have an even bigger impact on the price since they created great concerns and worries for the buyers, which pushed the price further up.

In the near future the fragile balance between supply and demand will not fade so quickly. The demand for oil is still increasing in western countries, but also in the fast growing countries such as India and China.

Although prices are high at the moment, when seen on the historic scale this does not mean that the price is indeed high when compared to the current market situation and future of oil reserve. Some say oil should be double or quadruple of the current price to fill the gap between oil and renewable energy sources, but higher prices will automatically make alternative energy resources more economical.

Currently it is expected that the world's demand for oil will increase about 2% per year in the first 25 years of the 21st century, according to the Energy Information Agency of the U.S. government. This makes it very clear that oil and gas companies will have to increase their production facilities to pump more oil and refine it into the products needed to keep the world economy going and growing.

Source:

http://www.hirednotfired.com

A Survival Guide to Chemical Engineering (by Dr. Lisa G. Bullard , Department of Chemical and Biomolecular Engineering North Carolina State University)

2012-03-06T21:04:00.001+07:00

1. Develop a strong work ethic.

This theme was echoed in almost every student response. There is no such thing as a lazy (successful) chemical engineer. You do not have to be brilliant to be a chemical engineer, but you do have to have the dedication, persistence, and downright stubbornness to keep working at it until you get it. Along the way you will doubt yourself. Those who really want it will succeed.

Most importantly, in order to understand a chemical engineering subject requires time, lots of time. Time spent reading the text, reviewing notes, speaking to the professor, working on the problem sets solely, working on the problem sets collectively, speaking to the TA, and going to problem session. One is also required to quickly develop a work ethic that has never been required before, because in high school they never studied and did well and freshmen year was hard but they still managed to do well with simply doing the homework and studying right before the test. This approach will not prove successful in chemical engineering.

2. Get used to working in groups.

I recommend that everybody taking these classes should have a group of people that they can study with. Everyone approaches complex problems differently so working with a team may allow someone to see an aspect of the problem that they would otherwise not consider.

At the beginning of your study, you may think you have it all under control. Don’t learn the hard way that a study group is a great source for understanding CHE material. In addition, you may be the resource someone else needs to understand a topic. Working in groups has mutual benefits. Remember, the group members need and value your input as much as you need and value theirs. I did everything short of going to the bathroom with my group.

3. …but don’t rely on group work to carry you through.

My instructors always emphasized working in groups, but being able to do the problems independently. Unfortunately, I didn't fully appreciate that advice until later on. The problems never look that difficult when you see the solutions your group members or instructors develop. The solutions are usually straightforward and relatively short.

However, the amount of trial and error and flipping through notes and books that it takes to develop those answers seems endless if you actually complete all the problems on your own. So when you sit down and take your first exam, you need to be able come up with these "short" answers on your own from all the information you have been taught up until that point. This can be difficult or impossible if you have relied on your group to carry you along.

4. Get organized.

Get organized and stay organized. I began each semester with everything in order and color-coded. As the semester progressed and the workload increased, before I realized what was happening, my organized notebooks and folders were in disarray. I soon learned the importance of setting aside just a few minutes one day a week to re-organize. It’s much easier to maintain organization!

You should be able to pick up notes from classes a year ago and be able to read and understand them. You should also be able to look at a problem you worked and know what you were doing.

5. Embrace CHE as a new community. Learn to love the AIChE Lounge and to join AIChE as early as possible. There is always someone there to help you if you need help, or if you just want someone to talk with. I think that is one reason that I like being a CHE so much — we all stick together and work with each other and generally care about each other. I would recommend that students visit the lounge if they have a problem they can't solve, generally there will be someone from their class or a helpful upperclassman that has been through it and knows their pain.

The best friendships of my life were found in the ChE lounge. CHE is more than a major, it is a lifestyle. If you look around the room in your chemical engineering class, you’ll see people that will become a significant part of life in the coming three (four) years. You may not realize it now, but you will be spending a large amount of time with them. They will inevitably become your friends as you share pains and triumphs in the coming years. Take some time to get to know them. Go out to dinner together and talk about something other than CHE.

6. Recognize that you have to train your brain to think differently.

Many students think the way to do well is to understand a little bit or memorize. In CHE, memorizing stuff is not important, but the way you THINK is. This retraining the brain to think like an engineer is trivial for some people, not hard for others, and nearly impossible for others that just don't understand how to apply concepts.

7. Get used to the idea that you will never see multiple choice tests again.

a. Studying tips [From a former TA]: Make a ‘per exam’ cheat sheet (cheat sheet for Exam 1, then 2, then 3) and figure out what you think will be most fruitful to put onto your “torpedo.” Do not make

the torpedo so confusing you cannot use it.

b. Practice. In ALL of your further CHE courses, practice in doing various types of problems is the key to doing well. You will encounter problems in tests that make you go to the next level and expand on what you already know.

c. Make your review problems that you do logical, neat and organized so you can always follow through what you did as a “summary” of the problem. You may get lucky and do a practice problem that the professor uses as an exam problem—it’s been known to happen!

d. Do not get into the habit of plugging and chugging. It will not serve you well. Understand what is going on, make a reasonable analysis of the problem, and try to figure out what you should be getting. Doing this through the review problems will make them sink in and you will then remember what to do on the final.

You have to invest the time before the test to know exactly how to find what you need in the book, and where it is. Putting tabs in your book might look geeky, but it will save you time in looking up commonly used tables and equations. And actually reading the book just might help, too.

8. Chemical engineering is not chemistry.

Engineering is different from purely scientific fields. Where chemists and physicists futilely search for truth, engineers realize and accept limitations and concentrate on whatis practical. Upcoming students should be ready to be trained in this way of solvingproblems. An engineering education seems to be more of a way of looking at the world and putting it to use than looking at the world and trying to explain it.

9. You can’t get away with procrastination.

I think that time management is the biggest thing that a student must learn when coming into the CHE curriculum. In other classes, it is often easy to wait until the last day to do an assignment, and still end up with a good grade. In CHE, it is a necessity to start the work early. There are too many concepts that will escape your grasp if you don't start early because the problems take a large amount of time, and you will never finish them in one sitting. Scheduling time to ask questions (with a teacher or TA) is also a must. It is inevitable that there will be a time when you get stuck on a problem, and none of your classmates are able to figure it out either. Basically, I believe it is impossible to procrastinate and be successful in the CHE curriculum.

10. Follow instructions.

The syllabus will probably say something like: “Use green engineering paper, one side of each page; begin each problem on a new page, and box the final answers. Each completed assignment should be in one person's handwriting. Staple the pages and fold them vertically when you hand them in, putting the names and roles of the participating group members and the problem set number and date on the outside.” Follow these instructions—to the letter. You can believe that the TA’s will take off points for not stapling, writing on the back, etc. You may think these 5 things are silly but if that’s what the prof asks for, do it. One day your client will ask for something just so—and that’s what they expect, too.

If the homework is due at the beginning of class, then it had better be there. Set two alarms, get your roommate to wake you up, whatever, but don’t be late or the rest of your group will hate you forever (deservedly). If in doubt, put it under the instructor’s door the night before (or at 3AM when you finish it). Writing legibly is a must. You can’t get partial credit if no one can decipher your scribbles.

11. Ask for help.

Get help when you need it. If you are unsure or completely lost, get help from other students in the class, the TA or the professor. Engineering classes are built upon information from your previous classes and previous lectures. If you get lost at one point, it is likely that you will be lost for the rest of the class and possibly longer. Don't make it harder on yourself; there is no shame in getting help. Don’t be embarrassed to go to the

Engineering Tutorial Center and get a personal or group tutor—that’s why they are there!

12. Choose a major for the right reasons.

[From a TA]: There was one commonality with the students who REALLY struggled in the class. During an informal talk with some of these students, I asked them why they chose chemical engineering. And all of them (these are the ones who get D's and F's in that class) told me that they chose chemical engineering because of the money or job opportunities. In contrast to that, the ones who did well tended to respond that they chose chemical engineering because they liked math and science. The students who were really struggling were hating every moment of the science, math and engineering courses.

13. Become comfortable making assumptions.

Now I have learned to list all the assumptions I am making when solving a problem. It is difficult to learn when you can make certain assumptions and when you can't. Making an assumption when describing a system might make my life easier while solving the problem, but it might not provide an accurate enough picture for the process, depending on the accuracy required. The more problems I work through, the more I know when it is okay to simplify a component/idea to get a solution.

In all the other classes I'd had, there were definite right and wrong answers to a given question; however, in chemical engineering class, there may be a number of different ways to arrive at an answer that might be considered correct. This took some getting used to.

14. Don’t be devastated if you aren’t at the top of the class. The majority of people in CHE were at the top of the class at some point during their academic career. Whether it was high school or freshmen courses, chances are you were too. You are now among the best, the competition is a little tougher, and the course material is going to be more difficult. You may not be at the top of the class, but always put forth your best effort. You may not always be satisfied with the result, but you’ll know you did everything you could do.
School and grades had been one of the most important things to me in my life up to this point, perhaps, sadly, the most important thing to me. (I say sadly because many parts of life are more important than grades, which are, after all, subjective and superficial. I now believe my spiritual state, my relationships with other people, actually learning, which is different from making good grades, and my health are more important).
I finished my freshman year with a 4.0 GPA. I had thoughts creeping in telling me that I may be the smartest person in the world. Then I took chemical engineering classes. I spent a LOT of time on the homework, and I made a ~70 on the first test. Since I thought I may be the smartest person in the world, I had figured my grades in my major should be even better than what I had been making This idea was supported by the fact that I did not think I had tried really hard to do well before, even in the classes that I did do well. Actually, I
was somewhat of a slacker and a procrastinator I began to realize that I had this attitude: I had to achieve perfection in order to have joy. I thought such a frame of mind was necessary to keep me motivated and doing well. Instead, not being content with anything less than perfection almost destroyed me. Having successfully completed the curriculum and obtained my degree, I now encourage you to study CHE for the sake of
learning, not for the sake of being the best.

15. Keep your eye on the goal. Listening to people talk about "real" chemical engineering and learning more about different industries and the application of chemical engineering principles can be quite helpful. Because chemical engineers go into such a broad array of fields, I think that it is all the more important that students begin considering where they might like to go early on by learning about what's out there (through attending lectures, conversations with professors/advisors, etc). When I was a junior in college, I felt a certain sense of shame because I could not name 10 chemical engineering-related companies, when in fact there are hundreds of companies which hire ChemE's.

[From an alumnus]: Encourage the students to view the course as representative of things that real chemical engineers do. Because of this, the hard work is very worthwhile, far beyond the value of getting a good grade. Some graduates (like those who go to medical school) will not use the material very much, but for many others it will be the very core of the value they present to their future employers. Particularly for people in process engineering, in research and development, or for others in the process industries, they will return to the content of this course over and over again. My group essentially applies 7 all the classical chemical engineering approach using the latest advances, but all our work has CHE 205 as a foundation. We use these ideas continuously to the point of them being second nature to us

[From an alumnus]: Embrace ChE with all its good and bad. We all love the title and the smugness we get from telling people "I'm an engineer, a CHEMICAL engineer." Kind of like "Bond, James Bond.." I feel good about it because I survived it, because I sacrificed to get it, and because I wanted it more than anything else - other than my family.

At this point, you may be thinking one of two things: (1) “This isn’t so bad, I think I can probably handle it if I just discipline myself to follow some of these common sense tips;” or (2) “Why would anyone want to survive such a hellish major…and where do I submit my drop form?” If you’re inclined to (2), let me offer some words of advice before you run screaming to Registration and Records.
First, chemical engineering is an exciting career field and is worth investing your time and effort. You will be able to work in a number of different industries including pharmaceuticals, petrochemicals, electronic materials, paper, textiles, consumer products, and more. You will have the skills to perform many different job functions, including research and development, process engineering, project management, sales, marketing, environmental assessment, quality assurance, technical support, information technology, and management. Many companies specifically target chemical engineers as new hires because they have found them to have a broad skill set and a strong work ethic. The fact that chemical engineers traditionally have the highest starting salaries of all engineering disciplines and the job market is always more stable for them than for most other
branches of engineering reflects the value that employers assign to a chemical engineering degree.

Second, others no smarter than you—and many not as smart—have trod this path before and lived to tell about it. Chemical Engineering alumni frequently cite the importance of problem-solving and teamwork skills that were developed during the chemical engineering curriculum and in chemical engineering classes in particular.And all those horror stories about 50% of the class getting F’s are not true—just look at recent grade distributions. In my Fall 2002 section of chemical engineering class, 70% of the class—those who stuck it out—got A’s or B’s. Lastly, if you think you’re the only one with doubts, think again. The quotation that follows is from an article about the “Impostor Phenomenon,” which is like a tape that people play inside their heads.

If you’re an engineering student looking around at your classmates, the
tape goes something like this: "These people are good—they understand
all this stuff. They really belong here…but I don’t. Over the years I’ve
somehow managed to fool them all—my family, my friends, my teachers.
They all think I’m smart enough to be here, but I know better…and the
very next hard test or hard question I get in class will finally reveal me as

he impostor I am." And what would happen next is too horrible to
contemplate, so at that point you just rewind and replay the tape. What
you don’t know is that almost everyone else in the class is playing the
same tape, and the student in the front row with the straight A average is
playing it louder than anyone else. Furthermore, the tape is usually wrong.
If you survived your first year of engineering school, you almost certainly
have what it takes to be an engineer. Just remember all your predecessors
who had the same self-doubts you have now and did just fine. You do
belong here, and you’ll get through it just like they did. Try to relax and
enjoy the trip.

So anchor your kayak, strap on your backpack, and let’s begin. Contrary to rumors you might hear, the natives are not hostile, and some of your fellow travelers actually look somewhat friendly. There may be some spine-tingling adventures ahead, some precarious positions to get through, and a few death-defying moments, but I assure you that the view from the heights is worth the climb.

Source:

A Survival Guide to Chemical Engineering
Dr. Lisa G. Bullard
Department of Chemical and Biomolecular Engineering
North Carolina State University

Perbandingan Gaji di Perusahaan Minyak dan Gas

2012-03-06T20:47:00.001+07:00

1. Chevron

Chevron adalah salah satu perusahaan energi terbesar di dunia. Pusatnya ada di San Ramon, California. Selain migas, Chevron juga bermain di eksplorasi, produksi, refinery, pemasaran dan transportasi, pembangkit energi, sampai chemical product.

Perusahaan ini berdiri tahun 1879 di Pico Canyon, California. Pada 2001, Chevron merger dengan Texaco dan membentuk ChevronTexaco. Namun pada 9 Mei 2005, ChevronTexaco melepas moniker Texaco dan kembali ke nama Chevron. Texaco tetap menjadi merek di bawah Chevron. Pada 19 Agustus 2005, Chevron bergabung dengan Unocal Corporation, sebuah gerakan yang membuat Chevron produsen terbesar energi geotermal di dunia.

Chevron terbilang cukup loyal terhadap karyawannya. Tabel di atas adalah berdasar PKB tahun 2006. Konon komponen tersebut sudah mencakup basic salary plus 21% regional allowance. Fresh graduate umumnya masuk di tingkat 18A.

2. China National Offshore Oil Corporation (CNOOC)

CNOOC cdalah perusahaan minyak dan gas bumi (migas) terbesar ketiga di Republik Rakyat China setelah CNPC (China National Petroleum Corporation) dan Sinopec. Perusahaan ini punya hak eksklusif untuk melakukan eksplorasi dan eksploitasi minyak mentah dan gas alam di lepas pantai China. CNOOC juga merupakan sebuah perusahaan milik negara yang mana 70% sahamnya dimikili oleh pemerintah Republik Rakyat China. Mereka juga terdaftar di NYSE dengan kode ticker CEO.

CNOOC hadir di Indonesia dengan nama CNOOC Southeast Sumatra Ltd sebagai salah satu perusahaan KKKS (Kontraktor Kontrak Kerja Sama) yang ditunjuk BPMIGAS untuk melakukan proses pengeboran minyak dan gas bumi di lepas pantai Laut Jawa, sekitar 90 km sebelah utara Teluk Jakarta, Indonesia.

Berdasar Peraturan Perusahaan 2006, gaji yang ditawarkan terlihat pada tabel di atas. Fresh graduate masuk ke CNOOC pada level 19.

3. ConocoPhillips

ConocoPhillips berpusat di Houston, Texas. Merupakan salah satu oil company besar yang memiliki lini bisnis terintegrasi — konon terbesar ketiga setelah Exxon dan Shell. ConocoPhillips lahir 30 Agustus 2002 sebagai produk merger antara Conoco Inc. dan Phillips Petroleum Company.

ConocoPhillips dikenal sebagai perusahaan dengan technological expertise untuk eksplorasi dan produksi di laut dalam, reservoir management and exploitation, 3-D seismic technology, high-grade petroleum coke upgrading, dan teknologi sulfur removal yang begitu sophisticated.

Menurut Peraturan Perusahaan 2006, gaji untuk karyawan terlihat seperti pada tabel di atas. Gaji mereka cukup bersaing dengan struktur gaji Chevron. Fresh graduate biasanya masuk di level 12.

4. ENI

ENI berpusat di Italia dan bermain di sektor minyak dan gas alam. Juga punya usaha di engineering and construction, electricity generation, dan petrochemical. Sejujurnya, saya kurang tahu pasti tentang bisnis dan pencapaian mereka. Sepanjang yang saya tahu, mereka ENI di Eropa Selatan dan juga punya (sedikit) kepentingan dan investasi di Indonesia.

Dari sounding orang dalam, struktur gaji di ENI untuk tahun 2004-2006 adalah seperti terlihat pada tabel di atas. Fresh graduate biasanya masuk pada tingkat ke 8.

5. Kuwait Foreign Petroleum Exploration Company (KUFPEC)

KUPFEC ialah perusahaan minyak bentukan Kuwait Petroleum Corporation yang beroperasi di beberapa negara di luar Kuwait, seperti Mauritania dan Mesir. Di Indonesia, mereka punya project di Buton dan telah memiliki interest di Blok Seram Non-Bula sejak 1985.

Struktur gaji KUFPEC terlihat seperti tabel berikut. Fresh graduate masuk di level 9. Struktur gaji tersebut adalah yang berlaku untuk tahun 2004-2006.

6. Pertamina

Perusahaan Pertambangan Minyak dan Gas Bumi Negara (Pertamina) adalah satu-satunya BUMN yang bertugas mengelola penambangan minyak dan gas bumi di Indonesia.

Pertamina pernah mempunyai monopoli pendirian SPBU di Indonesia, namun monopoli tersebut telah dihapuskan pemerintah pada sekitar tahun 2000-an. Pertamina mengoperasikan 7 kilang minyak dengan kapasitas total 1.051,7 MBSD, pabrik petrokimia dengan kapasitas total 1.507.950 ton per tahun dan pabrik LPG dengan kapasitas total 102,3 juta ton per tahun.

Pertamina adalah hasil gabungan dari perusahaan Pertamin dengan Permina yang didirikan pada tanggal 10 Desember 1957. Penggabungan ini terjadi pada 1968. Direktur utamanya saat ini adalah Ariffi Nawawi. Saya kurang mengetahui perkembangan Pertamina sejak sepeninggal Ari Soemarno. Namun yang jelas, Pertamina menyelenggarakan usaha di bidang energi dan petrokimia: sektor hulu dan hilir, serta ditunjang oleh kegiatan anak-anak perusahaan dan perusahaan patungan yang jumlahnya begitu banyak.

Pertamina adalah salah satu yang cukup loyal dalam memberi gaji dibandingkan perusahaan-perusahaan “made in Indonesia” lainnya. Gambaran gaji karyawan Pertamina dapat dilihat pada tabel berikut. Fresh graduate ada di level 8. Konon, benefit, fasilitas, termasuk “sambilan” di Pertamina bisa lebih besar dari basic salary-nya. Ada yang bisa memberi konfirmasi?

7. Star Energy

Star Energy adalah perusahaan energi yang juga terintegrasi dengan unit bisnis minyak, gas, dan listrik. Berpusat di Inggris, perusahaan ini sebenarnya lebih dikenal sebagai perusahaan energi daripada perusahaan migas.

Di Indonesia, Star Energy dibuka tahun 2003 oleh Supramu Santosa dengan kerjasama menggandeng Nusantara Capital.

Susunan basic salary Star Energy terlihat pada tabel berikut. Data bersumber pada buku peraturan perusahaan tahun 2006. Fresh graduate biasanya masuk pada entry level ke 8.

8. Tately N.V.

Tately N.V. adalah perusahaan eksplorasi dan rekayasa perminyakan asal Malaysia. Mereka berkongsi dengan PEXCO Group di Indonesia untuk menggarap PSC di Palmerah (Jambi) dan Lhokseumawe (Nanggroe Aceh Darussalam).

Basic salary Tately terlihat pada tabel berikut. Data bersumber pada peraturan perusahaan tahun 2006. Gaji tersebut adalah basic salary yang berlaku pada tahun 2006. Fresh graduate masuk di level 7.

Dibandingkan Petronas, nama Tately memang kurang bergema. Namun, mereka (katanya) menawarkan gaji dan benefits package yang tak kalah kompetitif. Kantor pusat mereka di Indonesia ada di Plaza Bapindo, Menara Mandiri.

9. Total S.A.

Total S.A. adalah perusahaan perminyakan asal Perancis yang berpusat di Paris. Mereka juga bermain di gas, crude oil, eksplorasi gas alam, transportation, refining, power generation, sampai product trading and marketing. Perusahaan ini juga terdaftar di NYSE dengan kode ticker TOT. Mereka juga dikenal bermain sebagai chemical manufacturer dan salah satu dari enam besar oil company di dunia.

Total beroperasi di lebih dari 130 negara dengan 111 ribu karyawan lebih. Di Indonesia, gaji yang mereka tawarkan terlihat pada tabel berikut. Data bersumber pada buku peraturan perusahaan tahun 2006. Fresh graduate masuk di level 10.

Menurut sejarahnya, Total hampir saja “diambil” oleh Royal Dutch Shell — andaikata waktu itu PM Perancis, Raymond Poincaré tidak ngotot agar Perancis membangun perusahaan minyak sendiri sesudah Perang Dunia I. Total akhirnya berdiri 28 Maret 1924 dengan nama Compagnie Française des Pétroles (CFP) mencaplok 23.75% kepemilikan saham Turkish Petroleum Company sebagai kompensasi yang diberikan Jerman melalui Konferensi Sanremo.
Tahun 1985 mereka mengganti nama menjadi Total CFP. Tahun 1991 mereka menghilangkan nama CFP. Pernah dikenal sebagai Total Fina setelah mengakuisisi Belgian Petrofina (1999) dan pernah juga dikenal dengan nama TotalFinaElf pasca merger tahun 2000. Kini mereka kembali menamai dirinya Total sejak 2003.
Disclaimer dari penulis di www.majarimagazine.com :

Penulis tidak terafiliasi dengan perusahaan migas apapun.
Informasi diperoleh dari peraturan perusahaan, riset dan analisis, sounding dari orang dalam, dan sumber-sumber informasi lainnya.
Pada saat informasi ini ditulis, barangkali sudah terjadi perubahan struktur gaji dari perusahaan-perusahaan tersebut di atas.
Informasi ini hanya digunakan untuk kepentingan edukasi semata. Penulis tidak bertanggung jawab terhadap penyalahgunaan data-data di atas.

Source:
www.majarimagazine.com

Kiat Membuat Proposal Magang dan KP

2012-03-05T21:12:00.001+07:00

Magang dan KP bagi beberapa orang memang mampu menjadi jalan 'pintas' untuk mendapatkan pekerjaan impian. Kegiatan ini tak hanya memberikan kesiapan mental saat melamar pekerjaan namun juga memberi gambaran riil dunia kerja.

Nurhadi, Direktur ECC UGM, mengatakan melamar magang atau KP ke perusahaan sama seperti halnya melamar sebuah pekerjaan. Anda juga butuh menampilkan potensi diri sehingga perusahaan layak menerima Anda untuk magang di perusahaannya. Potensi ini mula-mulanya dilihat perusahaan melalui proposal yang Anda kirimkan. Lalu, bagaimana cara membuat proposal magang dan KP yang baik? Simak tip-tip berikut.

Pertama. Sampaikan tujuan Anda dengan jelas sehingga perusahaan tahu apakah mereka bisa memenuhi keinginan Anda. Karena tidak selalu kebutuhan perusahaan sejalan dengan kebutuhan Anda. Siapa tahu load bidang pekerjaan yang Anda lamar sedang tidak membutuhkan tenaga tambahan. Tuangkan tujuan tersebut dalam bentuk kegiatan.

Kedua. Menjelaskan rencana kegiatan dengan detail. Cantumkan berapa lama kegiatan tersebut bisa Anda lakukan. Benefit apa yang perusahaan bisa terima dari kegiatan Anda tersebut. Dan jika perlu, gunakan konsep 5W+1H (What, When, Who, Why, Where, and How). "Akan lebih baik lagi jika kegiatan tersebut jelas-jelas bisa mengatasi masalah perusahaan," ujar Sri Muliati Abdullah, Staf Ahli Bagian SDM dan HR Service ECC UGM. Satu poin yang perlu diperhatikan dalam penyusunan kegiatan adalah mempertimbangkan kemampuan, periode, dan beban kerja Anda.

Ketiga. Pilih lokasi dan pekerjaan magang sesuai minat Anda. Meski sifatnya wajib dan berbeda dengan magang, Anda tetap boleh memilih di perusahaan dan jenis pekerjaan seperti apa yang akan Anda lakukan saat KP. Tapi tentu saja sesuai dengan background studi Anda. Misalnya, jika Anda mengambil jurusan Teknik Kimia, Anda bisa memilih bidang kegiatan tentang pangan, energi, ataupun lingkungan. Apapun, sesuai dengan minat Anda. "Kalau berminat, maka dia juga akan termotivasi menjalaninya," ujar Waziz Wildan, Ketua Jurusan Teknik Mesin dan Industri UGM.

Keempat. Tentu saja, proposal magang atau KP akan diperhatikan perusahaan ketika ada yang memayungi kegiatan tersebut. Pastikan proposal Anda mendapat pengesahan dari fakultas. Sertakan surat ijin permohonan magang dari instansi tersebut. "Kalau ada apa-apa, perusahaan akan mudah menelusur datanya," terang Sri Muliati Abdullah.

Nah, lalu berkas apa saja yang sebaiknya Anda lampirkan bersama proposal permohonan magang?

Seperti apa yang disebutkan di atas, selain proposal Anda juga harus menyertakan surat ijin magang dari fakultas yang bersangkutan. "Di jurusan kami juga ada Surat Perintah Kerja Praktik sebagai legalitas si anak dalam menjalankan KP," terang Waziz Wildan. Selain itu, Anda bisa juga menyertakan transkrip nilai sementara.Nurhadi menambahkan untuk menyertakan biodata beserta pengalaman organisasi Anda. tuliskan pengalaman ini secara mendetail beserta deskripsi kerjanya. "Jadi meski tidak melalui proses wawancara, perusahaan tahu Anda bisa," ujarnya. Proposal magang dapat dikirim melalui dua cara, yakni via pos maupun via email.

Untuk membuat proposal Anda diperhatikan, ada baiknya menuliskan 'perihal surat' di amplop luar jika Anda mengirimnya via pos. Jika Anda mengirim via email, tuliskan subject yang membuat si pembaca langsung tahu bahwa email tersebut berisi permohonan magang. Misalnya, "Permohonan magang/KP".

Selamat mencoba.. ^^

Source:

ecc.ft.ugm.ac.id

Magang : Jalan 'Pintas' Mendapatkan Pekerjaan Impian

2012-03-05T21:11:00.000+07:00

Apa Anda mahasiswa tingkat akhir yang sedang berencana magang atau kerja praktek (KP)? Jika iya, baca dulu artikel ini.

Banyak istilah untuk menggambarkan kegiatan mencari pengalaman di perusahaan bagi mahasiswa. Ada yang menyebutnya magang, KP, ataupun PKL. Namun sebenarnya, beda istilah beda pula hasilnya.Ir. M. Waziz Wildan, Msc. PhD., Ketua Jurusan Teknik Mesin dan Industri UGM, mengatakan magang sama dengan bekerja untuk perusahaan. Sehari-hari dia melakukan pekerjaan selayaknya karyawan perusahaan.

Magang tidaklah wajib di beberapa jurusan perguruan tinggi. Magang bisa juga dilakukan karena inisiatif sendiri. "Biasanya ada mata kuliah tertentu, dan dia butuh magang untuk bisa mendalaminya, semua tergantung kebijakan jurusan masing-masing,"ujar Nurhadi, Direktur ECC UGM. Ada juga mahasiswa yang melakukan magang dengan tujuan untuk bekerja di perusahaan tersebut. Tak mengherankan jika kemudian hasil akhir yang diharapkan adalah diterimanya mahasiswa tersebut untuk bekerja di perusahaan tempatnya magang. "Tidak untuk memenuhi SKS, sehingga tidak mendapat nilai," tambah Waziz Wildan.

Sedangkan KP biasanya dilakukan untuk memenuhi kebutuhan SKS. KP juga menjadi syarat kelulusan. Benar saja, Waziz Wildan mengatakan jurusannya menerapkan 2 SKS untuk kegiatan ini. Kegiatan saat KP biasanya harus sesuai dengan kegiatan yang ada dalam proposal serta kebutuhan perusahaan. Memang berbeda, namun keduanya memiliki manfaat yang hampir sama.

Pertama, Anda bisa mempraktekkan teori yang sudah Anda dapat di bangku kuliah. "Memberikan wawasan riil tentang industri ke mahasiswa," ujar Waziz Wildan. Dengan magang atau KP, Anda tidak hanya menguasai teorinya, tapi juga belajar bagaimana prakteknya.

Kedua. Anda akan merasa lebih percaya diri ketika sudah saatnya mencari kerja. "Karena secara skill dia sudah siap, sehingga dia merasa lebih percaya diri," ujar Nurhadi.

Ketiga. Selain skill, Anda juga mendapat pengalaman mengenal bagaimana budaya kerja di perusahaan. Tentu berbeda antara dunia kuliah dan dunia kerja. Dengan magang atau KP, Anda memiliki banyak kesempatan mengetahui bagaimana budaya di dunia kerja.

Keempat, luasnya jaringan karir. Jika Anda mampu menampilkan performa kerja yang optimal, siapa tahu perusahaan melirik Anda untuk bekerja di perusahaan tersebut ketika lulus nanti.

Nah, karena banyak manfaatnya, magang atau KP harus dijalani dengan serius. Beberapa perusahaan, seperti Schlumberger dan Nestle, menerima magang karena ingin mendayagunakan mahasiswa magangnya. Oleh karenanya, mereka tidak sembarangan dalam memilih karyawan magang. "Disesuaikan dengan kebutuhan perusahaan dan core bisnisnya," ujar Nurhadi. Karena magang juga berpotensi bagi seseorang diterima menjadi pegawai. Anda juga jangan sembarang pilih. "Pilih yang sesuai ketertarikan, apa yang ingin dikejar, dan gali ilmu sebanyak-banyaknya," tutur Nurhadi. Pilih perusahaan dan bidang pekerjaan yang memang menjadi ketertarikan Anda. "Kalau berminat, maka dia juga akan termotivasi menjalaninya," ujar Waziz Wildan.

Kapankah waktu yang tepat untuk magang dan KP?

Sri Muliati Abdullah, Staf Ahli Bagian SDM dan HR Service ECC UGM, mengatakan KP idealnya dilakukan saat teori sudah hampir habis. "Biasanya semester 7," ujarnya. Mengapa? Selain karena teori-teori sudah habis dipelajari, menurut Nurhadi mahasiswa di semester 7 biasanya sudah mengetahui minatnya di mana. Sehingga mahasiswa menjalani KP pun bukan karena sekadar memenuhi SKS. Lebih dari itu, mereka bisa mengejar apa yang menjadi ketertarikan mereka.

Berbeda lagi dengan magang. Mungkin waktu pelaksanaan magang bisa lebih fleksibel dibanding KP. "Kan ada juga magang yang dilakukan untuk memenuhi mata kuliah tertentu," ujar Sri Muliati Abdullah. "Biasanya kalau sudah dekat-dekat tugas akhir, sekalian melakukan riset," terang Waziz Wildan.Nah, ada beberapa poin penting yang sebaiknya mahasiswa lakukan saat magang atau KP, yakni:

Satu. Sebagai siswa magang atau KP, Anda sebaiknya mempelajari aturan dan budaya perusahaan. Menjalani magang atau KP sama halnya dengan bekerja. Anda juga butuh beradaptasi agar apa yang menjadi tujuan bisa diraih. Tentu Anda tidak mau, dicap buruk oleh perusahaan usai magang atau KP.

Dua. Menjalankan kegiatan yang sudah dituliskan di proposal. Tunjukkan Anda memang memiliki potensi untuk melakukannya. Jangan justru tidak serius dan seenaknya.

Tiga. Menggali sebanyak-banyaknya ilmu, khususnya dari atasan Anda. "Kan ada banyak laboratorium, manfaatkan saja," tambah Nurhadi. Apalagi jika magang yang Anda lakukan ditujukan untuk menunjang riset tugas akhir Anda.

Terakhir. Tentu saja, lakukan konsultasi teratur dengan dosen pembimbing. Mintalah saran ketika Anda menemui kesulitan di lokasi magang atau KP.

Source:

ecc.ft.ugm.ac.id

Top Colleges Offering Petroleum Engineering Courses in USA

2012-03-04T10:24:00.001+07:00

S.No.	University Name	State	Rank	Tution Fee / App. Fees	Accept. Rate	Deadline/Fall / Spring	Avg GRE / TOEFL
1	University of Texas Austin (Cockrell)	TX	1	$11,748 / $75.00	22.50%	1-Jan / 1-Oct	1300 / 213
2	Stanford University	CA	2	$37,110 / $105.00	28.00%	See Comment	1360 / 230
3	Texas A&M University College Station (Look)	TX	3	$8,712 / $75.00	37.20%	1-Mar / 1-Oct	1269 / 213
4	University of Tulsa	OK	4	$778 (per credit hour) /$40.00	47.90%	15-Jan	1159 / 213
5	Colorado School of Mines	CO	5	$21,744 / $70.00	70.30%	1-Apr / 1-Sep	1204 / 213
6	Pennsylvania State University University Park	PA	6	$26,050 / $45.00	31.90%		1221 / 213
7	University of Oklahoma	OK	7	$12,432 / $90.00	69.90%	1-Apr / 1-Sep	1194 / 213
8	Louisiana State University Baton Rouge	LA	8	$11,281 / $25.00	38.70%		1189 / 213
9	University of Southern California (Viterbi)	CA	9	$22,734 / $85.00	46.60%	15-Jun / 1-Oct	1236 / N/A
10	New Mexico Institute of Mining and Technology	NM	10	$11,901 / $16.00	47.80%	15-Feb / 15-Sep	N/A / 207
11	Texas Tech University	TX	11	$472 (per credit hour) / $60.00	38.90%	1-Mar / 1-Sep	1171 / 213
12	University of Kansas	KS	12	$575 (per credit hour) / $55.00	61.10%	10-Jan	N/A / 200
13	West Virginia University	WV	13	$15,664 / $50.00	46.20%		1149 / 213

Source:
http://www.accesseducationindia.com

Top Petroleum Engineering Universities

2012-03-04T10:22:00.000+07:00

Following are some of the top leading universities for petroleum engineering:

Heriot-Watt University (UK)
- The postgraduate Institute of Petroleum Engineering (IPE) is world renowned for its research on optimising economic hydrocarbon recovery. It has received 5* research ratings in the 1996 and 2001 Research Assessment Exercises.
- In 1995 Heriot-Watt received one of the inaugural Queens Anniversary Prizes for Higher and Further Education in recognition of the outstanding achievements of the Institute of Petroleum Engineering.
- In 2006 the Energy Institute granted accreditation to the MSc Petroleum Engineering and MSc Reservoir Evaluation & Management courses.
- The Petroleum Engineering department is consistently rated one of the top three in the world.

Texas A&M University (USA)
- The Harold Vance department of petroleum engineering at Texas A&M University is one of the top petroleum engineering programs in the United States. According to US News and World Report, the department has been rated the 1st among undergraduate petroleum engineering program in the United States.

University of New South Wales (Australia)
- The School of Petroleum Engineering (SCOPE) was established in 1985 as a joint initiative between UNSW and the petroleum industry.
- SCOPE is Australia's longest standing undergraduate and postgraduate petroleum industry training school.

The University of Adelaide (Australia)
- The Australian School of Petroleum (ASP) was created at the University of Adelaide in July 2003 by the merger of the National Centre for Petroleum Geology and Geophysics (NCPGG) and the School of Petroleum Engineering and Management (SPEM).
- ASP is one of only a few institutions in the world offering fully integrated teaching and research programs covering petroleum geoscience, engineering and management.

Source:
worldranking.blogspot.com

What Do Chemical Engineers Do?

2012-03-04T10:18:00.001+07:00

Chemical engineers play a crucial role in everyday life. Chemical engineers are involved in the design, modification and operation of processes to produce desirable products. They are employed across a huge variety of sectors including:

Chemicals and allied products
Pharmaceuticals
Energy
Water
Food and drink
Materials
Oil and gas
Process plant and equipment
Biotechnology
Business and management
Consultancy

Chemical engineers must make decisions concerning:

Which reaction pathway should be used to make the product?
How to purify the desired product
How to control the process and ensure it's safe
How to make the process cost effective
What should be done with any by-products formed?
How to reduce the amounts of unwanted by-products formed
What to do with unreacted raw materials
How to recycle energy within the process

Here are some examples of job roles for chemical engineers:

Project Engineer - Project engineers organise and run projects for engineering companies, this can be anything from managing a small modification to an existing pharmaceutical facility, to building a multi-billion dollar petrochemicals complex.

Design Engineer- The design engineer is responsible for determining how the process is to work. For example which pieces of equipment will be needed and how big they will be.

Operations Engineer - Operations engineers work "on site". This means that they spend their time ensuring that the plant is producing the right amount of product to the correct specification.

Research and Development Engineer (R&D) - The R&D engineer is innovative and creative. They develop the ideas for future plants, improving efficiency, environmental performance and even developing new products.

Coal Bed Methane Product Water

2012-03-04T09:55:00.001+07:00

The quantity of the CBM product water:
Extraction of CBM involves pumping large volumes of water from the saturated coal seam in order to release the water pressure holding the gas in the coal seam. What to do with this volume of often marginal-quality CBM product water is a source of much debate. Each well produces 5 to 20 gallons of water per minute. At 12 gallons per minute, one well produces a total of 17,280 gallons of water per day. It is common to have to have one well every 80 acres, and in the Powder River Basin, there are up to three methane-bearing coal seams. Therefore, there may be up to three wells per 80 acres.

The quality of CBM product water and its effects on soil: CBM product water has a moderately high salinity hazard and often a very high sodium hazard based on standards used for irrigation suitability. Irrigation with water of CBM product water quality on range or crop lands should be done with great care and managed closely. With time, salts from the product water can accumulate in the root zone to concentrations which will affect plant growth. Saline conditions stunt plant growth because plants must work harder to extract water from the soil.
The sodium hazard of CBM product water poses additional threats to certain soil resources. Sodic irrigation water causes soil crusting and impairs soil hydraulic conductivity, adversely affecting water availability and aeration and subsequent crop growth and yield. Upon wetting of soils containing swelling clay, sodium causes the degree of swelling in the clay to increase, leading to dispersion and migration of clay particles. Current research at Montana State University shows that water with sodium levels equal to typical Montana CBM product water can degrade the physical and chemical properties of heavier, clay soils, making such soils completely unsuitable for plant growth.
The risk of sodium degradation has been observed in other soil textures. Jim Oster (personal com.) observed crusting, poor soil tilth, hardsetting and aggregate failure on a sandy loam soil irrigated with water with EC ~ 1 and SAR ~ 7. Minhaus (1994) saw irreversible and severe reduction in infiltration on sandy loam soil with long term irrigation under high SAR water followed by monsoon rain.
There are many factors in addition to soil textures that affect infiltration rates. Mineralogy, lime, sesquiozides, organic matter content, cultivation, irrigation method, wetting rate, antecedent water content and time since cultivation all play a roll in infiltration. The only way to be certain of the impacts of saline/sodic irrigation water on the soil is to periodically sample and test the irrigation water and the soil.

The quality of CBM product water and its effect on plants:
Disposal of the quantities of CBM product water into stream channels and on the landscape poses a risk to the health and condition of existing riparian and wetland areas. High salinity and sodium levels in product water may alter riparian and wetland plant communities by causing replacement of salt intolerant species with more salt tolerant species. It is well recognized that encroachment of such noxious species as salt cedar,
Russian olive, and leafy spurge is enhanced by saline conditions.

What are the current management practices for disposal of CBM product water?
Currently, CBM product water in the Powder River Basin is managed by the following methods:
• Discharged into a stream channel - Although direct stream discharge is no longer permitted on new wells, existing operations were "grandfathered" and are still discharging directly into streams. Also, proposals are being advanced to allow regulated discharges during certain flow conditions.
• Impounded - This method involves constructing a pond in which CBM product water is stored or allowed to infiltrate to the subsurface. There are several terms for these impoundments: "holding ponds", "zero discharge ponds" or "infiltration ponds". Although they do not directly discharge water on the land surface, most impoundments are not lined and do discharge to the subsurface. Some percentage of seepage flow from impoundments is likely to reach stream channels via subsurface flow.
• Land applied to crop or rangeland - through some form of irrigation equipment.
• Other uses - CBM product water is also used for dust control and, in some cases, is being used by coal mines.
Another option proposed for disposal of CBM product water in eastern Wyoming and Montana is to reinject the CBM product water back into an aquifer(s). This practice occurs in the southwest U.S., where CBM product water is injected into formations below CBM-bearing coal. This approach avoids surface discharge. Many opinions exist, and the feasibility - economic, physical, and environmental - of either reinjecting CBM product water to the coal seam from which it was pumped or injecting it into an aquifer above or below the CBM-bearing coal seam is being investigated.

Can CBM product water be treated to make it more usable? The only ways to lower the salt concentration in saline and/or sodic water are through dilution with non-saline water, reverse osmosis, or salt precipitation with an evaporation process that leaves salt behind and traps evaporated water. Reverse osmosis is expensive, and evaporation and salt precipitation treatment is neither economical nor feasible with large quantities of saline CBM water. Dilution of CBM product water is only possible if there is a large source of non-saline water with which to dilute the saline water.
It is possible to alter the chemistry of sodic water by adding calcium and magnesium. This does not eliminate or reduce sodium, but changes the ratio of sodium to other salts, thus decreasing the sodium adsorption ratio (SAR). The net result is more saline water with the sodium salt still dissolved in the water. This approach is not likely to work with CBM product water because the added calcium will combine with carbonate from the
CBM water and precipitate out as calcium carbonate (lime). To make this process work,CBM product water must be de-gassed of carbonate by addition of acid, or additional calcium must be made available in the soil by acidification from sulfur additions.Unfortunately, addition of more salts to water or soil may result in conditions too saline for plant growth.

Source:
Frequently Asked Questions Coal Bed Methane (CBM)
Kristin Keith and Jim Bauder, Montana State University-Bozeman
John Wheaton, Montana Bureau of Mines and Geology (2003)

Coal Bed Methane (CBM) and CBM Product Water (ex. in Powder River Basin

2012-03-04T09:33:00.000+07:00

What is coal bed methane?
The primary energy source of natural gas is a substance called methane (CH4). Coal bed methane (CBM) is simply methane found in coal seams. It is produced by non-traditional means, and therefore, while it is sold and used the same as traditional natural gas, its production is very different. CBM is generated either from a biological process as a result of microbial action or from a thermal process as a result of increasing heat with depth of the coal. Often a coal seam is saturated with water, with methane is held in the coal by water pressure. Currently, natural gas from coal beds accounts for approximately 7% of total natural gas production in the United States.

How do people estimate the amount of methane gas which will come from a region underlain by coal? There are two popular methods of estimating recoverable methane gas from a coal seam.
a. One method requires estimating methane reserves by boring to the top of the coal seam, then extracting a core from the coal. The amount of methane recovered from the coal core is used to estimate gas content per unit volume of coal. If a number of cores are drilled and methane gas release is observed, one can estimate the amount of gas available in a region. The limitations to this method are:
1) there is much disturbance to the coal seam core before gas release is measured;
2) it is expensive
3) not every region of potential CBM development has been drilled and explored
b. Another method of estimation is through a series of calculations based on information already known about the coal in the region and the feasibility of CBM development. For instance, the Montana Bureau of Mines and Geology estimated the amount of recoverable CBM in the Powder River Basin using the following information:
• A coal seam has favorable reserves if it produces 50-70 ft3 per ton of coal.
• CBM extraction is economical at 50 ft3 per ton of coal when a coal seam is 20 feet thick or more.
• Coal bed methane exists only in areas where the dominant chemistry of the water in the coal seam is sodium bicarbonate and where the coal seam is buried deeply enough to maintain sufficient water pressure to hold the gas in place.
The Environmental Impact Statement for CBM development in the Powder River Basin estimated the amount of coal in the region based on the total reported tonnage of coal in the region multiplied by 50 ft3 of methane per ton of coal, irregardless of seam thickness, depth or proximity to outcrop.

How do gas companies extract methane from a coal seam?
Since CBM travels with ground water in coal seams, extraction of CBM involves pumping available water from the seam in order to reduce the water pressure that holds gas in the seam. CBM has very low solubility in water and readily separates as pressure decreases, allowing it to be piped out of the well separately from the water. Water moving from the coal seam to the well bore encourages gas migration toward the well.
CBM producers try not to dewater the coal seam, but rather seek to decrease the water pressure (or head of water) in the coal seam to just above the top of the seam. However, sometimes the water level drops into the coal seam.

Are coal seams aquifers?
Yes. Water flows through fractures (or cleats) in the coal seam and if the cleat system is well developed and has enough water to pump and produce an economically viable and feasible water supply, the seam can be an aquifer. Coal seams are the most regionally continuous geologic unit in the Powder River Basin and have aquifer characteristics equal to or better than sandstones, so are frequently targeted for water-well completions.

I've heard people talk about aquifer drawdown from CBM development. What does this mean?
Ground water flows through coal seams due to water pressure, or hydrostatic head. When the pump in a well is turned on, the amount of water than can be produced is controlled in part by the static water level, which is the original hydrostatic head in the well. As the pump withdraws water from the aquifer and discharges it at the surface (whether it is to a stock tank, house, or CBM discharge point) the water pressure (head) in the aquifer is reduced. The greatest reduction in water pressure is near the well, with progressively less change at increasing distances from the well. If we could see this reduction in water pressure it would be shaped like a funnel or cone with the spout in the well. This area of reduced water pressure is called the cone-of-depression. When the pump is turned off, water flowing through the coal aquifer replaces the discharged water, and the water pressure returns to static conditions. An idealized ground-water flow system, and one
where the head shows the drawdown associated with CBM production are shown in the following figures.

Within the cone-of-depression, there is less water pressure in the aquifer, and therefore less water can be produced from a well (or spring). The percentage change is greatest near the central or deepest part of the cone-of-depression. The amount of change in water pressure and the distance from the producing well to the limit of change depends on many factors, including the static water level, pumping rate, aquifer characteristics, and how long water is produced. Also, the time needed for water pressure to return to static conditions is dependent on the same parameters. In cases with a field of producing wells, as is the case with CBM, the size of the cone-of-depression and recovery time are both increased significantly.

Some individuals say that the depleted aquifers in the Powder River Basin will be recharged within a matter of years, while others think the time might be more on the scale of a thousand years or more. Who is right?
Aquifer recharge is the process whereby precipitation or surface water infiltrates below land surface and begins to flow in an aquifer system. Ground water flowing through coal seams in the Powder River Basin has infiltrated along clinker or scoria ridges, in stream valleys, and in some cases in sandy soils during years of heavy precipitation. In the case of CBM product water, recharge occurs many miles away from development sites.
According to the Montana Bureau of Mines and Geology, monitoring and groundwater modeling indicates somewhere between a few years and 20 years for recharge to occur. The question of recharge time is a challenging one. In coal mining areas, recharge occurs within a few years (typically 3 to 4). However, open pit or strip coal mines normally cover an area of only a few square miles, and because the area of impact is relatively small, recharge can occur rapidly. With CBM extraction, the area of impact may be as large as many adjacent townships (1 township=36 mi2). In such large geographic areas recharge depends on the time it takes recharge at the coal seam outcrop to move to the CBM developed area (Wheaton, 2002).

I heard that almost all CBM product water discharged to the land surface eventually reaches the aquifer from which it was pumped. Is this true?
MSU scientists contend that most likely only a small percentage of CBM water returns to the aquifers from which it was pumped. Rather, the water recharges shallow alluvium and coarse soil material aquifers near the land surface, less than 200 feet deep, or is lost to evaporation. If CBM product water is directly discharged into a stream channel (this is no longer allowed, but there are sites that were "grandfathered") it can flow downstream, evaporate, or percolate to groundwater through the stream channel. Land applied or stored CBM product water evaporates or percolates to shallow groundwater.
Once water reaches a shallow aquifer, where it goes is very site specific. The aquifer water pressure (head) may increase, and/or the water may flow laterally to a spring or become baseflow to a nearby stream. There are reports in the Powder River Basin that some stream channels are carrying more flow than before CBM development, and there are reports that some streams have no increase in flow. With our current level of knowledge, it is very difficult to predict what will happen to the water once it reaches the shallow aquifer system.
In Gillette, WY, the Pennaco company is reinjecting water back into the depleted aquifer which supplies water for the city of Gillette. Pennaco, and other companies in the Powder River Basin, are investigating the feasibility of injecting CBM product water at several sites in the area.

Will CBM development reduce flow to streams, springs and wells?
As a result of the large amount of water being pumped from coal seam aquifers, there is concern of impact to springs and streams and to the level of water in drinking and livestock wells. The answer to this question is very location specific. If a spring or stream is fed by a coal seam aquifer (the coal seam surfaces and discharges water into a stream or spring), CBM development in the local area may decrease flow to those water bodies.
If a spring or stream is not fed by a coal seam aquifer, decreases in flow would be minimal. However, if CBM product water is land applied or impounded in a holding pond (most often these ponds are not lined and discharge to the subsurface), streams down slope may have increased flow during development due to subsurface flow.
If a drinking water or livestock well gets water directly from a coal seam, then CBM development in the local area may decrease the water level in that well. Duration of impacts to spring flow and water available from wells will depend on the total area developed and timing.

Source:
Frequently Asked Questions Coal Bed Methane (CBM)
Kristin Keith and Jim Bauder, Montana State University-Bozeman
John Wheaton, Montana Bureau of Mines and Geology (2003)

Spiral Wound Heat Exchangers

2012-03-03T12:58:00.000+07:00

These heat exchangers have a broad temperature and pressure range and are used in single phase and two phase applications. They are able to handle many streams depending on the customers need. Pressures of up to 3625 psi can be handled sufficiently. The materials of construction of this exchanger include austenitic steels, aluminum alloys, carbon steel, nickel and chrome/moly alloys. This wide range of materials and the special features associated with the geometry of the heat exchanger allow for a wide range of applications.
The surface area of heat transfer can be as high as 20,000 m2 but the maximum diameter is limited to 7,500 mm and a weight of approximately 260 tons per unit. It is possible to have larger diameters or higher weights but their feasibility has to be checked depending on the customer’s needs.
The material of construction chosen depends on the customer’s needs. Simulations are The exchanger consists of a center hollow tube with tube bundles that spiral round it. The center tube and the tube bundle are housed in a metal column. The outer column does not have a uniform diameter. The bottom part has a larger diameter than the top part. Figures A and B show the outer shell and the tube bundles respectively. used for strength calculations of pressure containing vessels. Features such as tube spacing, tube support, bundle support and flexible mandrel are selected based on proven design technology developed over many years.

Source:
Evaluation of LNG Technologies (by Valerie Rivera, Ayema Aduku, Oluwaseun Harris)

April 30, 2008

Plate Fin Heat Exchangers

2012-03-03T12:49:00.002+07:00

These heat exchangers are widely used in cryogenic application because of their low cost, small size, low weight, high thermal capacity and effectiveness relative to other types of heat exchangers. The result of the improved effectiveness is the achievement of true counter current flow where there is an increase in the temperature spread and a closer approach to ideality. This means that the refrigerant cooling curve is closer to the natural gas cooling curve.
The exchanger is made up of manifolds or headers which consist of elements. A manifold and an element are shown below, Figures 4 and 5 respectively. An element is made up of a corrugated die-formed fin plate placed between flat metal separator plates. There are side bars along the outside of the fin sections. A stack of the elements is welded to form a rigid matrix and can be designed to meet any configuration and size. The stacks are welded onto the manifolds. Depending on the application, a number of manifolds can be assembled to form the heat exchanger.

Manifold or Header (xchanger.com)

An element

The wavy configuration of the fin promotes turbulence and therefore improves heat transfer. This increase in heat transfer is accompanied by an increase in pressure drop. This is a problem with low density fluids like gases because of the extra work required to surmount the pressure drop.

Fin Configurations

This work is often much higher than the increase in heat transfer acquired from the fins. For applications where it is proposed any fin configuration other than the simplest, a thorough analysis of the effect on the system should be conducted.

In designing the plate fin heat exchanger, it is possible to have different heights of the alternating fin plates. There is no requirement to have the same height or spacing of separator plates. This is a useful freedom to have in situations where the difference in density of the hot and cold fluids is large. In cryogenic systems, the refrigerant stream entering the expander has a higher density than the stream coming out of the expander. In such a case as this, it is necessary to use a larger height for the lower density stream so that a common Reynolds number and therefore heat transfer coefficient, U, can be attained.

Aluminum is the usual material of construction of plate fin heat exchangers for cryogenic applications. (Walker, 104-110)

Source:
Evaluation of LNG Technologies (by Valerie Rivera, Ayema Aduku, Oluwaseun Harris)
April 30, 2008