Process Simulation of Urea Plant
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This document summarizes the key properties, production, and uses of urea. It discusses that urea has a molecular weight of 60.05 and formula of NH2·CO·NH2. It is used primarily as a solid or liquid fertilizer but also in resins, animal feed, and other applications. Urea production involves compressing ammonia and carbon dioxide in an autoclave, then processing the liquid effluent through flash drums to form an aqueous urea solution or molten urea that is prilled into granules. The main raw materials are ammonia and carbon dioxide.
Process Simulation of Urea Plant
- 1. Under the guidance of Prof. Ashish Gangwal By Rahul Ghalme Chemical Engineer
- 2. Properties of urea 1) Molecular Weight: 60.05 2) Molecular Formula: NH2·CO·NH2 3) Melting Point: 132.7 4) Boiling Point: Decomposes 5) Fairly soluble in water 6) State : Crystal prismatic or powder 7) Flammable Limit : Non-flammable 8) Density : 1323 kg/m3 at 20-24C
- 3. End uses: Urea is used in solid fertilizer, liquid fertilizer and miscellaneous applications such as animal feed, urea, formaldehyde resins, melamine and adhesives. Production Pattern : Urea is the nitrogen compound with the largest production volume In world. Its utilization is increasing steadily, it being the preferred nitrogen fertilizer. Because it is the world wide shift to the high nutrient-high nitrogen fertilizers provided by urea in solid or aq. solution form. Urea can be easily granulated.
- 5. Raw materials: The principal raw materials required for this purpose are CO2 from synthesis gas manufacture and NH3 . Process description: 1. Ammonia and CO2 are compressed separately and added to the high pressure autoclave which must be water cooled due to highly exothermic nature of the reaction. The average residence time in autoclave which is operated on cont. basis is 1.5-2 hours. A mixture of urea , ammonium carbamate , water and unreacted NH3+ CO2 results. 2. The liquid effluent is let down to 27 atms and fed to a special flash evaporator containing a gas liquid separator and condenser .
- 6. Unreacted water, NH3 , CO2 as a solution are thus removed and recycled. An aq. Solution of carbamate urea is passed to atmospheric flash drum where further decomposition of carbamate take place. The off-gases from this step can either be recycled or sent to NH3 process for making chemical fertilizer. 3.The 80% aq. Urea solution can be used as is or sent to a vacuum evaporator to obtain urea containing less than 1% water. The molten mass is then sprayed into a prilling tower.
- 9. a) Autoclave variables b) Carbamate decomposition and recycle c) Production of granular urea(Prilling) d) Heat dissipation in autoclave e) Corrosion