Ammonia a base compound used in chemical process industries to produce commercial chemical product. Produced in large scale from synthesis gas, that in-turn generated from natural gas, naphtha or fossil sources rich in hydrogen content.
Existing process technologies obtain hydrogen from fossil chemicals and nitrogen from air. These two compounds are reacted in a reactor to produce ammonia. However, if the source for this process is obtained other than fossil chemicals then ammonia production too, becomes green technology.
Project on this concept helps to develop a system that uses biogas as a raw material. Methane content in biogas is about 60-70 percent approximately depending on the bio matter. Hydrogen can be obtained from methane by partial oxidation or auto thermal processes to generate synthesis gas containing carbon monoxide and hydrogen. Nitrogen supplied from air during the above process is sufficient in composition for ammonia reaction on a catalyst. However, carbon dioxide and carbon monoxide should be removed to maintain the feed ratios.
Design engineers, process engineers, chemical engineers and industrial engineers can build up project report regarding this concept. If the design is successful than it could change the production of ammonia from large scale to small scale with less energy consumption more over turning the process into green technology.
Unit operation that may be used in the process sequence are:
Biogas digestor: organic matter cutting, slurry formation( culture, pH).
Biogas purification or upgradation: MEA or KOH absorption and even PSA.
Syngas production: Dry reforming or auto thermal reforming.
Carbon dioxide removal by absorption: K2CO3 absorption and stripping.
Ammonia reactor: Fixed bed catalytic reactor.
Ammonia purification and storage: Purging and refrigeration system
Bottle neck of the process can be identified at the syngas production and carbon dioxide recycling steps. These two steps govern the heat requirement and CO2 emission from the process. By process simulation an optimistic method can be identified. ASPEN plus or CHEMCAD are sophisticated and well equipped with simulation tools and packages.