Natural gas ammonia synthesis process

You can go to Sichuan Chemical to find out; the code is 000155

Kellogg natural gas–steam conversion process: The raw natural gas is compressed by a compressor to 4.2 Mpa. The natural gas at the compressor outlet undergoes wet desulfurization, with hydrogen sulfide being absorbed using an ethanolamine solution. The desulfurized natural gas is then heated to 370 degrees Celsius by the feed gas preheating coil located in the convection section of the first-stage converter; it combines there with some of the gas coming from the first stage of the syngas compressor. After this mixing, the hydrogen content reaches 10%, and the mixture enters a cobalt-molybdenum hydroconversion reactor, where organic sulfur is converted into hydrogen sulfide. Subsequently, the gas proceeds to a zinc oxide desulfurization unit for dry desulfurization. The desulfurized natural gas is mixed with steam at a water-to-carbon ratio of 3.5, and heated to 510 degrees Celsius by the mixed feed gas coil located in the convective section of the first-stage converter. It is then fed into the converter tubes where it undergoes conversion reactions under the action of a nickel catalyst. In the first stage of the converter, the exit temperature of the conversion gas is 820 degrees Celsius, with 9.7% methane content, and then the gas proceeds to the second stage of the converter. The converted gas enters the second-stage converter, where it mixes thoroughly with preheated air and burns. The two-stage furnace serves two purposes: one is to supply nitrogen for the ammonia synthesis reaction ； The second is to complete the final conversion of methane at higher temperatures, with about 0.33% methane present. The gas coming out of the two-stage converter is at approximately 1003 degrees Celsius; it enters the waste heat recovery system, and the gas that emerges from there goes into the shift reactor. The shift converter includes two reactors: a high-temperature shift reactor and a low-temperature shift reactor. High-temperature shift uses iron-based catalysts, while low-temperature shift uses copper-based catalysts. The shifted gas exiting the low-temperature shift reactor contains about 0.5% carbon monoxide and enters the carbon dioxide absorption tower. Decarburization is carried out using the Phenol method; the Phenol solution consists mainly of a 27% potassium carbonate solution along with the corrosion inhibitor V2O5 and the activator DEA. The absorbed carbon dioxide is sent to the urea system via a desorption system. The CO2 content in the gas exiting the carbon dioxide absorption tower is less than 0.1%, after which it enters the methanation purification system. In the methanation reactor, under the action of a nickel catalyst, CO and CO2 in the gas react with H2 to produce CH4 and water respectively; after cooling, the gas enters the syngas compressor and proceeds to the low-pressure synthesis system.

The processes include:  Compression and desulfurization of feed gas  Conversion using a heat-exchange converter  Carbon monoxide shift reaction  Decarburization  Methanation  Drying  Deep cryogenic purification  Compression  Ammonia synthesis  Ammonia refrigeration  Ammonia recovery via circuit venting  Process condensate stripping tower  Steam system