Ratio of cold ammonia to hot ammonia in ammonia synthesis
Thread Content
In existing ammonia synthesis plants, after the ammonia outlet, the stream is divided into two paths: one path carries hot ammonia at 1.6 MPa and around 20°C to the ambient-temperature ammonia tank. In the cold ammonia refrigeration system, cooling is achieved through circulation; part of the cooled energy is recovered by decompression and then sent to low-temperature, normal-pressure ammonia tanks. These tanks can be used to sell ammonia, or the ammonia can be pressurized and heated before being sent to normal-temperature ammonia tanks. I would like to ask about the control of the ratio between cold ammonia and hot ammonia in normal production
How to set it: Based on the requirements for cold ammonia and hot ammonia, it is recommended that the ratio between these two be 1:1.5. However, due to the different characteristics of the nitrogen addition systems in various sections, or as a result of specific on-site conditions, it may be necessary to adjust this ratio to make it more appropriate and effective.
How was the 1:1.5 ratio determined?
The ratio control of cold ammonia and hot ammonia should be determined based on actual usage conditions. Generally, more cold ammonia is used than hot ammonia, as hot ammonia affects the performance and efficiency of the equipment. Furthermore, an appropriate ratio should be selected based on the actual process flow and performance parameters of the ammonia synthesis plant, as well as the characteristics of the chiller system, in order to ensure efficient and safe production
I also consulted the design institute, and we all agreed that under normal operating conditions, urea is primarily produced using hot ammonia, while cold ammonia is used as a supplement for freezing purposes, to assist in regulating inventory or for selling ammonia; it is not used in long-term operation scenarios. However, the person in charge of the initial selection of the company’s process package suggested that cold ammonia should be used for continuous operation, with a certain proportion of hot ammonia also being used; he asked me about that proportion value, which left me a bit confused, so I’m seeking advice!
You’d better ask a synthetic ammonia manufacturing company in Weifang, Shandong – they might have it. I asked one in Zhejiang, and their answer wasn’t very clear either; perhaps the equipment supply department there can give you an answer
Thank you, I’ll wait a bit longer for the expert!
Isn’t it determined based on the process requirements?