Introduction to different ammonia production processes

Ammonia due to the different processes used in the production process also has some differences, but the basic production process are similar, basically by the production of raw gas, raw gas purification, compression of syngas and ammonia synthesis of four parts.

Synthesis of raw gas

1) Solid fuel production of raw gas: coke, coal

2) Liquid fuel production: naphtha, heavy oil

3) Raw gas for gaseous fuel production: natural gas

Purification of raw material gas

1)Desulfurization

2)CO conversion

3)Decarbonization

Syngas compression

Ammonia synthesis

Industry, the raw materials used in the preparation and purification of different methods, and composed of different processes, a variety of raw materials for ammonia production of typical processes are as follows.

1) Coke (anthracite) as raw material process

Before the 1950s, most of the ammonia plants in the world adopted the Haber-Bosch process. Coke as raw material for tons of ammonia energy consumption of 88GJ, more than four times higher than the theoretical energy consumption. Based on the Haber-Bosch process, China developed the carbonization process and the three-catalyst purification process in the late 50s and early 60s.

Carbonization process flow will be pressurized water washing instead of ammonia to remove CO2 obtained by ammonium bicarbonate by crystallization, separation as a product. Therefore, the process is characterized by the combination of gas purification and ammonia processing.

The three-catalyst purification process uses three catalysts, namely, desulfurization, low-temperature conversion and methanation, to purify the gas to replace the traditional copper-ammonia liquid washing process.

2) Natural gas as raw material process

The natural gas first undergoes cobalt-molybdenum hydrogenation catalyst to convert organic sulfide into inorganic sulfur, and then desulfurizer is used to remove the sulfur content to below 0.1ppm, which not only protects the normal use of the reforming catalyst, but also provides conditions for the application of low-temperature conversion catalysts, which are susceptible to sulfur poisoning.

3) Process with heavy oil as raw material

When heavy oil is used as the raw material for ammonia production, partial oxidation method is adopted for gas production. The raw gas from the gasifier first removes carbon black, and then undergoes CO sulfur conversion, low-temperature methanol washing and nitrogen washing, and then is compressed and synthesized to obtain ammonia.