How does desulfurization and decarbonization of the conversion gas of synthesis ammonia react?

After conversion, the organic sulfur in the gas is converted to H2S, which requires secondary desulfurization to keep the sulfur content in the gas at 25 mg/m3. The main task of decarbonization is to remove CO2 from the conversion gas and purify the gas. The conversion gas from the conversion section with a pressure of about 1.3MPa enters the water separator, and the separated water is discharged to the gutter. The conversion gas enters the adsorption tower for adsorption, and after adsorption, it is sent to the fine desulfurization section.

The impurities and a small amount of hydrogen and nitrogen adsorbed by the adsorbent will be released from the lower end of the adsorption tower under depressurization and evacuation, and this part of the gas is called resolved gas, which is depressurized and desorbed in two steps, of which the part with higher pressure is recovered in the downstream release stage through the pipeline into the gas cabinet, and the desorbed gas with lower pressure than atmospheric pressure is discharged into atmosphere through the flame arrester.

Conversion and desulfurization process flow chart for ammonia synthesis