FORMAT OF PURPOSAL
- 1. Title page Saad, Ali Raza, M.Ali, Usama 19-Dec-2016 NFC IEFR, FSD
- 2. Executive summary Urea is to be prepared by NH3 and CO2 through ammonium carbamate. NH3 and CO2 is passed through reactor. Where ammonium carbamate is produced. Then ammonium carbamate is moved to a stripper at low pressure and high temperature where it decomposes to urea. Then urea formed is moved to rectifying column where additional substances are removed from urea and then urea is passed through single effect evaporator and them vaccum evaporator. These evaporator will make the urea highly concentrated. Then finally highly concentrated urea is moved to prilling tower where granulars of urea is formed through seeding process. The final product obtained is 99% concentrated urea.
- 3. Table of content No. Topic page no. 1. Introduction . 2. Background . 3. Procedure . a) Stripper . b) Rectifying column . C) BFD Diagram . c) Cooling tower & scrubber . d) Single effect evaporator . e) Vacuum evaporator . f) Periling tower . 4. Equipment . 5. Personnel . 6. Reference .
- 4. Introduction Urea is produced by CO2 and NH3. The purpose is to minimize the cost of production of urea by installing only one reactor by changing the temperaute and pressure. The quality of urea produced will be observed and compared with two reactor system method. Morever rectifying column is also installed which will separate the unreacted NH3 and CO2 from urea. NH3 and CO2 will be recycle back to reactor so that more quantity of ammonia can be produced. Heat produced from the reactions will be recovered up to maximum extent by using Combination (combi) Boiler which is latest boiler.
- 5. Background Recently urea was prepared with two reactor system by previous batch students at NFC IEFR. They use two reactors and didn’t use and recovery system. We are using one reactor but installing recvovery system.
- 6. Procedure The process consists of two main equilibrium reactions, with incomplete conversion of the reactants. The first is carbamate formation: the fast exothermic reaction of liquid ammonia with gaseous carbon dioxide (CO2) at high temperature and pressure to form ammonium carbamate (H2N- COONH4): Reactor: CO2 and liquid ammonia will be introduced in the reactor to produce ammonium carbamate, at high temperature and pressure. The reaction is highly exothermic, and heat from this reaction will be recovered as steam.
- 7. Stripper: The mixture (ammonium carbamate & unreacted NH3 & CO2). The mixture will be moved to stripper, where ammonium carbamate will be decomposed to urea at high temperature and low pressure. Low pressure will cause unreacted gases to separate from liquid urea. Rectifying Column: The mixture(UREA, NH3, CO2, NH2COONH4). The mixture from stripper will be moved to rectifying column through a expansion valve, which lower the pressure up to 0.5MPa & in rectifying column pressure will be further reduced to 0.1MPa. This low pressure will separate gases & liquid. Gases are recycled to reactor & liquid which is urea solution will be moved to evaporator.
- 9. Cooling Tower & Scrubber: The recycle gases from rectifying column will move to cooling tower where they are absorbed in cool water. This hot mixture then moved to scrubber, which will separate the gases from water at low pressure. The purpose is to recover heat from gases & finally the gases will be moved to reactor to produce the further urea. Single Effect evaporator: Urea solution from rectifying column is 75% concenterated, is move to single effect evaporator, where urea will be made up to 85% concenterated.
- 10. Vacuum Evaporator: Here the ammonia solution will be concentrated up to 90%. The hot water from both evaporator will be recovered in the form of heat energy. Periling Tower: In prilling towers 90% concentrated urea is move to where hot air and water will be provided which will make the urea granular. There will be already present some urea granular so that urea crystals formed through seeding process, & final product will be obtained is 99% concentrated urea.
- 12. Personnal We are four person group. Saad sahi, B.sc chemical engg. From University of Cambridge United Kingdom Explore, M.sc industrial engg. From Harvard University Muhammad Ali, B.sc chemical engg. From Hong Kong University of Science and Technology M.sc metallurgy engg. From University of California, Santa Barbara Ali raza, B.sc chemical engg. From Stanford University, M.sc agri engg. From Princeton University Usama Butt, B.sc chemical engg. From Cambridge universty, M.sc nuclear engg. From MIT USA
- 13. References Manures and fertilizers by A.K KOLAY Urea Production Technology by Mark Brouwer Chemical process industries