The large-scale chemical fertilizer plant in Sichuan Tianhua Co., Ltd. was established in the 1990’s, where the C. F. Braun Process is applied for synthetic ammonia production and the ammonia stripping process for urea production. During normal production, output matching between ammonia and CO2 in the synthesis workshop shows a slight surplus of the former, and the seal gas of the CO2 compressor in urea plant is directly discharged to the air. Therefore, the Company has decided to recover the seal gas, which may reduce environmental pollution on one hand, and improve the economic benefits by making use of the surplus ammonia and the discharged CO2 to increase the load of the urea plant on the other hand.
We add a certain amount of air to the venting seal gas to changes its composition. The flow of the venting CO2 is calculated to be around 700-750 m3/h by means of determining the flow of air added with a portable rotameter. The recovery is designed based on this approximate value.