The issue of make-up gas for ammonia synthesis

Synthetic make-up gas is also known as fresh gas or inlet gas. It refers to the gas that enters the synthesis system.

This post was last edited by snowdfr on 2009-8-22 08:07. 1. What is supplemental air? Makeup gas, also known as fresh gas or purified gas, is the gas that has been purified and pressurized using hydrogen and nitrogen compressors before being sent to the ammonia synthesis tower. 2. What is the role of supplementary gas? The ammonia synthesis reaction is a volume-reducing reaction, and fresh gas is continuously supplied to maintain production. 3. Supplemental air flow process? Depending on the design processes of various units, the make-up gas is supplied either before the ammonia cooler or after it; those with a high purity level are sent directly to the ammonia synthesis tower. Regarding this, the original poster can take a look at this link to find out the location where supplemental gas is added. 4. What are the typical components of supplemental gas? Mainly hydrogen and nitrogen. There is also methane and argon, along with trace amounts of CO, CO2, etc

Synthetic make-up gas, also known as feed gas, is high-purity, trace amounts of fresh gas. The location for adding synthetic make-up air is quite important. The introduction is as follows: For the renovation and expansion of ammonia synthesis plants as well as new projects, due to factors such as oil removal technology, oil-water separation technology, and process configuration, and with the aim of protecting the catalyst in the synthesis tower, the ammonia synthesis system processes typically adopt two traditional approaches offered by our company: the new system and the old system. Both of the above processes share common characteristics: the make-up gas must be combined with the gas exiting the synthesis tower after ammonia separation, followed by a second ammonia separation step. The advantage of this approach is that the make-up gas is washed and separated from oil and water in the condenser, thereby ensuring that oil and water do not enter the catalyst layer of the synthesis tower and thus protecting the catalyst there. However, from an economic perspective, it is not cost-effective. Firstly, due to the addition of make-up gas, the ammonia concentration in the gas during the second ammonia separation in the ammonia synthesis system decreases, resulting in a corresponding reduction in the amount of ammonia separated under the same temperature conditions. Secondly, it is because the make-up gas brings some ammonia into the synthesis system cycle.

Thank you, I mainly didn’t understand the concept! Now I understand: our fresh gas inlet passes through liquid nitrogen washing, and after compression it is mixed with the ammonia-containing circulating gas before being compressed together and fed into the synthesis tower! Going even further from where we already are!

Makeup gas, also known as fresh gas, is refined gas that comes from compressed air at six stages. It passes through the ammonia cooler, the oil separator, and the condensation-evaporation separator (2) in sequence, then mixes with the recycled gas and enters the condensation-evaporation separator (1), the turbine, the oil separator, before entering the synthesis tower. Since the reaction in the synthesis tower can produce approximately 15% ammonia, the reaction gas remaining after ammonia separation is recycled for further use. But the ammonia is separated away, and as the gas goes through synthesis, the amount of ammonia that remains decreases continuously; without adding supplementary gas, how can production continue?