How to adjust the high-pressure system after product discharge from the synthesis tower

For both CO2 stripping and ammonia stripping processes, during startup, once the output from the urea synthesis tower begins, the stripping tower starts to operate under load. At this point, the amount of CO2 and ammonia – the reactants that enter the high-pressure condenser and the urea synthesis tower – increases. It is important to pay close attention to the pressure in the high-pressure section in order to avoid overpressure.

The process after the system starts operating and discharging material is a very complex one, with clear regulations regarding the adjustment procedures. The main points are as follows: 1. The system composition is appropriate for stability. That is: after the stripping tower is put under load, reduce the speed of the ammonia reduction pump, lower the steam pressure on the shell side of the high-temperature cooler, close the gas-phase outlet valve of the high-pressure washer, and increase the speed of the low-pressure ammonium methanate pump, etc. 2. Stabilizing the material flow: first, maintain a stable liquid level in the synthesis tower; thereafter, gradually stabilize the material flows in the stripping tower, the low-pressure cycle, and the low-pressure absorption process in sequence from front to back. 3. Stable adjustment of the steam system: this involves adjusting the steam balance in various components such as the steam on the shell side of the stripping tower, the steam on the shell side of the high-temperature cooler, the low-pressure cycle heaters, as well as those used for evaporation and hydrolysis. 4. Stabilizing the low-pressure system. 5. Starting up the evaporation process or increasing its capacity, etc