1. Plant Design of Cryogenic distillation of Air to Oxygen and Nitrogen Project By: Bhusare Abhijit (Gr. No. 111390) Ghalme Rahul (Gr. No. 111448) Modi Vrajesh (Gr. No. 111027) Guided By: Prof. A. K. Vaddi 2. Introduction Air (M.W. = 28.96 g/mol ) is composition of various gases. 3. High purity components in air applied in different chemical industries. 1904- Worlds first ASU for production of high purity air components Largest markets - Chemicals and gasification, petroleum refineries, electronics and metals industries. First industrial manufactures of oxygen was Brin process 1806- Faraday liquefied many gases by application of pressure, but not H2, O2, N2 1877- Pictat and Caillete liquefied first O2 and many gases. Prof. Linde- First man producing liquid O2 on commercial scale. 1970s- First application of computer control to improve efficiency and productivity of ASU. 4. Kolhapur Oxygen Pvt. Ltd. (Kagal MIDC) 5. INOX AIR PRODUCTS Pvt. Ltd. (Jejuri MIDC) 6. Literature Survey Global market for industrial and specialty gases will reach 10.15 trillion cubic feet by 2015. Major growth Factors- high demand from end user industries such as energy, healthcare and electronics. Growth due to R&D activities focusing on new applications. 7. Applications of Air Products Medical oxygen Oxygen- Glass manufacturing, chemicals and petroleum processing, pharmaceuticals, pulp and paper (increase paper whiteness), aerospace, wastewater treatment and even fish farming. Oxygenenriched air increases production efficiency in steel, rocket fuel, glass, chemical, gasification and metallurgical processing applications. Manufacturers of Al, Cu, gold and lead use oxygen to remove metals from ore. Nitrogen- Oil and gas industries, metal working, electronics, food processing. Refineries, petrochemical plants and marine tankers use gaseous nitrogen to clean out vapours and gases from the equipment they use. Recyclers use liquid nitrogen to cool plastic and rubber so they can grind them and recover key raw materials to manufacture new products. 8. Process Selection Different Manufacturing Processes 1. Low temperature (Cryogenic) rectification of liquid air 2. Membrane separation 3. Electrolysis of water 4. Brin process 5. Brin process using cobalt compounds 9. Process Selection Oxygen Production Process Selection Grid 10. Cryogenic Air Separation Two steps 1. Liquefaction Production of low temperatures Linde Process (JT Effect) 2. Separation of liquid air by rectification By integrated distillation column 11. Process Description Equipments used 1. Compressor 2. Heat Exchanger 3. Valve 4. Molecular Sieve 5. Separator 6. After Cooler 12. Process Description Five major steps of manufacturinfg O2 and N2 1. Air compression 2. Air purification 3. Cooling of air 4. Air separation 5. Product collection Product Validation 1. Oxygen Test 2. Nitrogen Test 13. Mass and Energy Balance Capacity of unit= 215 ton/day gaseous O2 =6300 m3/hr Quantity of intake air=34500 m3/hr Component Volume % Nitrogen 78.03 Oxygen 21.00 Argon 0.94 Hydrogen 0.01 Helium 0.0003 Krypton 0.00011 Xenon 0.00009 CO2 0.03-0.06 Moisture 0.02-0.05 14. Mass Balance Equipment Material In (K mol/Hr) Material Out (K mol/Hr) Input 1540.18 - 65% Stream 1001.17 - After Cooler 1001.17 998.49 Heat Exchanger 998.492 997.03 35% Stream 539.063 - Molecular sieve 539.03 538.478 Low pressure distillation column 1535.55 L2=209.734 S=456.746 W=869.07 High pressure distillation column L2=209.734 S=456.746 W=869.07 N2=361.61 WN2=892.69 O2=281.25 15. Energy Balance Equipment Enthalpy at Inlet (K cal/Hr) Enthalpy Out (K cal/Hr) Compressor 1 5701515.3 5800672.1 Compressor 2 2030235.2 1752557.962 After Cooler 3770436.8 3567701.7 16. Energy Balance Heat (K cal/Hr) Heat Exchanger High Pressure HE Heat given by dry air 1476342.02 - Heat lost by CO2 1308.78 - Heat lost by water 1609.632 - Heat gained by N2 422037.5 - Heat Lost by Air - 442741.5 Heat gained by O2 - 312603.33 17. Equipment Design Design of Distillation Column L/V ratio at the top of both columns to be 0.58 F = amount of feed = 1535.55 kmol/hr W = Bottom product from lower, refluxed back to the top column (rich liquid) S = Side stream from lower column, refluxed back to top column (impure liquid) Xf = mole fraction of N2 in feed = 0.79 Xw = mole fraction of N2 in IPL = 0.96 X1 = mole fraction of N2 in top product = 0.99 18. F = W + S + L2 ----------- (1) F Xf = W Xw + S Xs + X1 L2 ------------- (2) Number of Plates (Graphically) Hence from the graph no. of theoretical plates = 17 19. Average molal of feed = 0.6127 Actual number of plates = 17/ 0.6127 = 27.74 28 plates From graph feed enters 12 plates Actual plate at which feed enters = 12/ 0.6127 Feed enters plate = 19 Total Height = 9.146 m 20. Mechanical Design of Distillation Tower Calculation Cylindrical Body of the Tower Cylinderical wall thickness (bottom) t = PL*DL/ (2 f J - PL) + C = 5.12 mm Now, t = 6 mm thickness are acceptable. Permissible pressure in the selected wall thickness against top wall [P] = [2 f J (t - C)]/ (DL + t - C) = 7.67 kg/cm2 f = PL (DL + t - C)/ 2.3*J (t - C) = 785.2 kg/cm2 Cylindrical body wall thickness (upper) t = [PH DH / 2 f J - PH] + C = t = 0.272 cm = 2.72 mm Now, t = 6 mm thickness are acceptable. Permissible pressure in selected wall thickness [P] and seizure against top wall [P] = [2 f J (t - C)]/ (DH + t - C) = 8.84 kg/cm2 f= [PH (DH + t - C)]/ 2.3*J*(t - C)= 181.5 kg/cm2 21. Calculation of Elliptical Cap and Bottom Elliptical bottom wall thickness t = PL*DL/ (2 f J - PL) + C = 5.12 mm Now, t = 6 mm thickness are acceptable. Permissible pressure in the selected wall thickness and seizure against the top wall [P] = [2 f J (t - C)]/ (DL + t - C) = 7.67 kg/cm2 f = PL (DL + t - C)/ 2.3*J (t - C) = 903 kg/cm2 Wall thickness of elliptical cap t = [PH*DH/ 2 f J - PH] + C = 2.72 mm Now, t = 6 mm thickness are acceptable. Permissible pressure in selected wall thickness [P] and seizure against top wall [P] = [2 f J (t - C)]/ (DH + t - C) = 8.84 kg/cm2 f = [PH (DH + t - C)]/ 2.3*J*(t - C) = 208.8 kg/cm2 22. Condenser Design Tha is inlet temperature of nitrogen vapor = -176.5 0C Thb is outlet temperature of nitrogen = -178.2 0C Tca is inlet oxygen liquid = -179.5 0C Tcb is outlet oxygen = -178.2 0C Therefore, T1 = 1.491 Now, taking overall HTC as 100 btu/hr ft2 0F = 567 W/m2.0C Q = U A T By using this equation A comes around 460 m2 Let N is the number of tubes so total heat transfer area = NDL Where, D = outer diameter, L = length We are choosing 1 inch OD and 14 BWG tubes of 8 inch lengths and calculating the number of tubes obtained is 2360. Taking triangular pitch of 1.25 inch and shell diameter = 1.67 m Now, as this values of Heat transfer coefficient U becomes 560.6 W. 23. Inside and Outside Coefficient Calculations Nitrogen in tube side hi = 240 btu/hr.ft2.0F ho = hi*(id/od) = 22.16 btu/hr.ft2.0F Oxygen in shell side ho = jHK/ De(c/k)-1/3 = 223.61 btu/ft2.hr.0F = 1267.8 W/m2.0C Clean overall coefficient UC = hio*ho/ (hio+ ho) = 598.865 W/m2. 0C Pressure Drop Shell Side: Ps = f.Gs 2.Ds. (N + 1)/ (5.22*1010 De*S) = 1.5222 psi Tube side: Pt = f.Gt 2.Ln/ (5.22*1010*Ds) = 0.155*103 psi 24. Plant Economics Plant Capacity and Basis Rated Plant Capacity = 215 tons/day of gaseous Oxygen 99.95% purity = 61500 tons/annum of Oxygen Basis: Number of working days = 25 days/month = 300 days/annum Number of shifts = 3 per day One shift = 8 hours 25. Fixed Capital Land and Building= 3, 85, 50,000.00 Plant and Machinery= 37, 58, 68,000.00 Other Fixed Assets= 6, 15, 00,000.00 Total Fixed Capital= 47, 59, 18,000.00 26. Working Capital Salary and Wages= 86, 19,000.00 Utilities and Overheads= 29, 71, 00,000.00 Total working capital per annum = 30, 57, 19,000.00 27. Production Cost Per Annum Total Working Capital per Month Total 2, 54, 76,583.00 Working capital for two months = 5, 09, 53,167.00 Total fixed capital = 47, 59, 18,000.00 Total Capital Investment = 52, 68, 71,167.00 Production Cost per Annum Working capital for one year = 30, 57, 19,000.00 Interest @ 13.50% on TCI = 7, 11, 27,608.00 Dep. @ 33% on plant and machinery = 12, 40, 36,440.00 Total 50, 08, 83,050.00 28. ROR and BEP By sale of O2- N2 = 88, 90, 00,000.00 Profit = Receipt Production cost = 38, 81, 16,950.00 Profit sales ratio = Profit/ Sales*100 = 43.65% Rate of return = Operating profit/ TCI*100 = 72% Break- Even Point (BEP) = Fixed Cost/ (Fixed cost+ profit) = 45% 29. Payback Period Payback Period= (Project Cost+ working capital borrowing)/ Gross Profit Per year Payback Period= 52, 68, 71,167.00/ 38, 81, 16,950.00 Payback Period is around 1 Year and 5 Months 30. Safety Thoroughly wash all oxygen fittings, valves and parts with clean Tricolor Ethylene /carbon tetra chloride (CTC) before installation. Do not lubricate oxygen valves, regulators, gauges or fitting with oil or any other substance. Do not fasten electric conduits to the plant or its pipelines. Do not experiment with liquid oxygen by putting solids or liquids into it for watching the effect of cold liquid as it may catch fire Pressure gauges across pipes at regular intervals as a check against leaks in the pipes and pressure relief valves for safety vent over pressurized gases No Smoking signs Workers should wear clean, loose fitting, thermalinsulated gloves; a longsleeved shirt and safety shoes. Do not breathe cold oxygen vapor. The temperature of the vapour rising from liquid oxygen is approximately -181 0C. 31. Conclusion As a part of feasibility study, we have investigated the feasibility of constructing a new green-field 215 tpd oxygen plant. As a part of study we have successfully designed major equipment like distillation column, heat exchanger etc. The plant is totally feasible and gives 99.95% pure product efficiently. The project can create employment for persons. 32. References Luyben, William L. "Design and Control of a Fully Heat Integrated Pressure-Swing Azeotropic Distillation System. Industrial & Engineering Chemistry Research 47.8 (2008): 2681- 695. Print. Perry R.H. Chilton, C.H. and Kirkpatrick, S. D. (eds). (1963) Chemical Engineers Handbook, 6th ed., Section 3 (New York: McGraw-Hill Book Company, Inc.) C. J. Geankoplis, Transport Processes and Separation Process Principles (Includes Unit Operations), 4th Edition, Prentice Hall, 2003. 33. THANK YOU