United Arab Emirates University College Of Engineering Chemical Engineering Department Graduation Project I

2. United Arab Emirates UniversityCollege Of EngineeringChemical Engineering DepartmentGraduation Project I The Design of Formaldehyde Production Plant • Group Members: • Abrar Abdalla Ahmed 200002089 • Ayisha AL-Marzouqi 200002243 • Huda Tag Hamza 200004386 • Noora Al-Mulla 200002122 • Supervisors: • Advisor: Dr. Mohammed Nounou

3. Objectives • First formaldehyde plant in UAE. • Economical, Environmental & safety.

4. Presentation layout 1- Formaldehyde background. 2- Process selection. 3- The description of the silver catalyst process. 5- Material and energy balances calculations. 6- Safety and environmental impact. 7- Preliminary cost estimation.

6. Formaldehyde background 1- Definition. 2- History . 3- Physical and chemical characteristics. 4- Availability and market. 5- Uses and applications.

7. Definition Simplest form of aldehyde Chemical formula HCHO

8. History USA Butlreov 1859 1901

9. Availability and market Japan Canada America

10. Availability and market Gulf region Saudi Arabia

11. Uses and applications

13. Formaldehyde Production Process 1- Oxidation of dimethyl ether 2- Partial oxidation of methane 3- Dehydrogenation and/or Oxidation of methanol

14. Dehydrogenation and/or oxidation of methanol Methanol processes Silver catalyst 75 % Metal Oxide catalyst 25 %

15. Process selection

17. N . . 7 6 5 4 3 2 1 88oC 35oC Tail gas water Water 145 oC Converter Distillation Column Cooling Water Absorber Air washer 88oC 145 oC Air 110 oC 160oC Methanol superheater 64.7oC 35oC Methanol vaporizer 37% CH2O1% CH3OH Fresh methanol Recycled methanol

18. Water steam 145 oC 145 oC Air fed Methanol superheater 160 oC 64.7oC Methanol vaporizer Fresh methanol Recycled methanol

19. Tail gas Water Recycled methanol Reactor effluent Product

21. (Material balance)Objective • Amount of raw materials • Compositions & flow rates

22. Degree of freedom Ndf = Nunknowns – Nindependent equations Nunknowns= 12 Msteam MH2O MTail gas Mmethanol Mair Compositions in tail gas: HCHO, CO2, CO, H2, H2O, C2H4O2, N2 Msteam MH2O MTail gas Mair Nindependent equations= 4 Mmethanol Mproduct atomic balance equations (H, N, C, O).

23. Degree of freedom Ndf = 12 – 12 = 0 Ndf = 12 – 4 = 8 20% Tail gas = H2 0.1%Tail gas = C2H4O2 EPA: - HCHO - CO2 - CO Yield = 0.92 Ratio of air to methanol 30% of the feed entering the reactor is steam

24. Recycled methanol : Fresh methanol 1:3 (Air : Methanol) fed to the reactor 0.9:1 Assumptions and specifications 30% of the reactor feed is steam Plant yield = 92%

25. N . . 7 6 5 4 3 2 1 Distillation Column Top product Basis Product = 5,707,762 kg/hr From absorber Bottom product

26. N . . 7 6 5 4 3 2 1 Fresh methanol = 2,448,547 Kg/hr 88oC 35oC Tail gas Yield =92% water Water 145 oC Converter Distillation Column Cooling Water Absorber Air washer 88oC 145 oC Air 110 oC 160oC Methanol superheater 64.7oC 35oC Methanol vaporizer 37% CH2O1% CH3OH Fresh methanol Recycled methanol

27. N . . 7 6 5 4 3 2 1 Recycled stream /Fresh methanol = 1 / 3 Recycled stream =812,611 Kg/hr 88oC 35oC Tail gas water Water 145 oC Converter Distillation Column Cooling Water Absorber Air washer 88oC 145 oC Air 110 oC 160oC Methanol superheater 64.7oC 35oC Fresh methanol Methanol vaporizer 37% CH2O1% CH3OH Recycled methanol

28. Air fed =2,656,138 Kg/hr Air / Methanol = 0.9/1 Water 145 oC Cooling Water Air washer 145 oC Air 160oC Methanol superheater 64.7oC Fresh methanol Methanol vaporizer Recycled methanol

29. 30% of reactor feed is steam Water steam =2,529,704 kg/hr Reactor feed =8,432,346 kg/hr Mixing point Mass in = Mass out Water steam 145 oC Cooling Water Air washer 145 oC Air 160oC Methanol superheater 64.7oC Fresh methanol Methanol vaporizer Reactor effluent =8,432,346 kg/hr Recycled methanol

30. N . . 7 6 5 4 3 2 1 Distillation Column Recycled stream Top Product = 812,611 kg/hr Feed = 6,520,374 kg/hr 88oC Product = 5,707,762 kg/hr 35oC 37% CH2O1% CH3OH

31. N . . 7 6 5 4 3 2 1 Tail gas =100,409 kmol/hr Tail gas water Overall carbon atomic balance Water steam 145 oC Converter Distillation Column Cooling Water Absorber 88oC 145 oC Air 110 oC 160oC Methanol superheater 64.7oC Product Methanol vaporizer Fresh methanol Recycled methanol

32. N . . 7 6 5 4 3 2 1 Neglect (H2O) in tail gas MWav.= 22.8 Kg/Kmol N2 = 0.72 Tail gas water Tail gas =2,249,102 kg/hr Water steam 145 oC Converter Distillation Column Cooling Water Absorber 88oC 145 oC Overall Nitrogen balance Air 110 oC 160oC Methanol superheater 64.7oC Product Methanol vaporizer Fresh methanol Recycled methanol

33. N . . 7 6 5 4 3 2 1 XN2=0.75 XH2O=0.009 Water =337,129 kg/hr Tail gas water Water steam 145 oC Converter Distillation Column Cooling Water Absorber 88oC Overall hydrogen atomic balance Overall mass balance 145 oC Air 110 oC 160oC Methanol superheater 64.7oC Product Methanol vaporizer Fresh methanol Recycled methanol

34. (Energy balance)Objectives • Amount of energy power requirements

35. Hv ,TD , m Qc HL HD ,TD QB Hw Energy balanceDistillation Column TD= 64.85oC HD HD = 0 kJ/hr Hf Tw= 91.5 oC Hw = Hf - HD Hw = Hf = 5.7*108 kJ/hr Hw = mw Cpw (Tw-Tref) Hw

36. Reboiler & condenser duties Condenser duty: Qc = Hv = 2.7*109 kJ/hr mH2O = 3.2*107 kg/hr HD Reboiler duty: Qrb = Qc + Hw +HD - Hf Qrb = 2.7*109 kJ/hr mH2O = 1.2*106 kg/hr Hf Hw

37. Cooler 1- Amount of cooling water mw Cpw (Tw – 35) = mH2O CpH2O (Tout – Tin) HD mH2O = 6.77*106 kg/hr Hf Hw 35oC 91.5oC

38. Energy balanceAbsorber 88 oC 35 oC Qrb =H15- HH2O - Hf Water , TH2O = 20 oC Qrb =6.56*108 kJ/hr Hf Qc = HH2O + Qrb +Hf – H15 – Hw TR = 110 oC Qc = 1.61*108 kJ/hr Hw

39. Methanol vaporizer & superheaterduties Q1+QR = mm Cpm (Tm-Tref) Tm = 56 oC QA QA = msteamH2O = mair CpairT QA=5*107 kJ/hr msteam=2.21*104 Qv =mm + mm cpm T = 3.64*109 kJ/hr msteam= 1.61E+06 kg/hr Qs Qv Q1 Qs= msteamH2O = mm CpmT = 5*107 kJ/hr msteam= 1.67E+06 kg/hr T 1 = 30oC T m , QR T R = 64.85oC

40. Energy balanceReactor 145 oC HR = -2.1*108 kJ/hr mH2O = 9.26*107 kg/hr Cooling water Qc = 1.6*109 kJ/hr Qc 110 oC 160 oC mH2O = 1.9*107 kJ/hr

42. Where does formaldehyde exist?

43. Sources of exposure Tobacco smoke Oil refineries Engine exhaust

44. Limits of exposure • Acute duration (0.04 ppm) • Intermediate duration (0.03 ppm) • Chronic duration (0.008 ppm)

45. Environmental Impact Formaldehyde in nature Air Soil Water

47. Plant Capital Cost Capital cost definition Step counting method C' = 13000 N Q0.615 Timm’s Correlation N: 3 Q: 50,000,000 tonne/ year C' = 2.12E+09 $ Cost in year 2004 =2.5E+09 $

48. Conclusion • Tasks achieved • Plan for next semester

49. References 1- Robert H. Perry, Don W. Green, Perry Chemical Engineer’s Handbook, seventh edition, McGRAW international, 2003. 2- K.Weissermel, H.-J.Arpe, Industrial Organic Chemistry, Third compeletely revised edition, VCH A wiley company, 1997. 3- R. Norrris shereve, Chemical process industries, fourth edition, McGRAW Hill book company,1977. 4- Kirk-othmer, Encyclopedia of chemical technology, fourth edition, volume 11, A wiley interscience publication, New York, 1992. 5- Sybil P. Parker, Encyclopedia of chemistry, second edition, McGRAW Hill book company, 1993, pages 408-410, 637-638. 6- Douglas M. Considine, Chemical and process technology encyclopedia, McGRAW Hill book company, 1974.