To produce urea from ammonia (NH3) and carbon dioxide (CO2) using the CO2 stripping process.
Ammonia and carbon dioxide react at 155 bar to synthesize urea and carbamate. The reactor conversion rate is very high under the N/C ratio of 3.7 with a temperature of 182°C–185°C. Unconverted materials in synthesis solution are efficiently separated by CO2 stripping. The milder operating condition and using two-phase stainless steel prevent corrosion problems. Gas from the stripper is condensed in a vertical submerged carbamate condenser. Using a high-pressure (HP) ejector for internal synthesis recycle, major synthesis equipment is located on the ground level.
The urea solution from synthesis section is sent to a medium-pressure (MP) decomposer at 17 bar and a low-pressure (LP) decomposer at 2.5 bar for further purification. No pure ammonia recycle is required due to the high separation efficiency in the stripper. The vacuum evaporator unit produces urea melt at the required concentration either for prilling or granulation.
The vent scrubber and process condensate treatment unit treat all emission streams; thus, the plant is pollution free. Process condensate is hydrolyzed and reused as boiler feedwater.
Toyo Engineering Corp. (TOYO) has a spout-fluid bed granulation technology to produce granular urea—typically 2 mm–4 mm size. Due to proprietary granulator, electric power consumption is the lowest among granulation processes.
Licensor: Toyo Engineering Corp. (TOYO)