Methods for desulfurization in the ammonia synthesis process
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I would like to ask what methods are currently used for desulfurization in large-scale ammonia synthesis?
This depends on what raw materials you choose to use for producing synthetic ammonia. If coal is used as the raw material, it becomes more complicated, as different choices need to be made depending on the quality of the coal. However, wet flue gas desulfurization is generally the primary method. If natural gas is used as the raw material, it is relatively simpler, and dry desulfurization is generally employed.
Thank you. What are the main methods used for wet flue gas desulfurization?
Wet desulfurization involves the use of roasted glue along with alkali, along with a small amount of desulfurizing agents such as 888 or MSQ; it offers many advantages, including good desulfurization efficiency (high desulfurization rate), low operating resistance, and low desulfurization costs； If the sulfur content in coal is high, a dual-tower configuration operating in series should be used: the first tower operates with spray drying, while the second tower uses a packed tower. This approach helps to reduce resistance, ensures an adequate desulfurization rate, and results in acceptable production costs. For large-scale plants such as 300,000–500,000 tons per year ammonia synthesis plants, the low-temperature methanol washing process should be considered; at such scales, this process offers advantages in terms of purity and energy savings.
Wet desulfurization, also known as wet oxidation desulfurization, involves the use of soda ash to absorb H2S. Some plants add resins, V2O5, and desulfurizing agents to the alkaline solution, while others use only alkali and desulfurizing agents. There are now many types of desulfurizers, mainly in the cobalt titanium cyanide series. The regeneration of desulfurized rich liquid uses the jet self-priming method.
Tannin method or 888 desulfurization method
Most of the newly installed ammonia synthesis plants now use low-temperature methanol washing. The operating cost is lower than that of NHD for desulfurization and decarbonization, while the manufacturing cost is slightly higher than that of NHD.
Our plant uses a low-temperature methanol wash unit for the production of 300,000 tons of synthetic ammonia.