Abstract:
Every atomic element ever in the history of the universe began as a H2 atom
that had undergone nuclear fusion within a star. In other words, every one of us is a
byproduct of H2. It is mainly used in the synthesis of nitric acid, which is used in
fertilizers and explosives. There are many processes from which we can produce NH3
including Haber process, Cryogenic process, NH3 from natural gas, Electrolysis, Partial
oxidation, Adiabatic reforming, Coal gasification. In this project, we have separate H2
from NH3 purge gas using Poly Sulfone Membrane Technology. In ammonia
production, hydrogen and nitrogen are reacted at high pressure to form ammonia. Since
the conversion per pass is not 100%, the reactor is operated in loop mode. In the
processes, a purge stream from an ammonia synthesis loop, which purge stream contains
NH3, is contacted at a super atmospheric pressure with the feed side of a separation
membrane which exhibits selective permeation of each of hydrogen and ammonia as
compared to the permeation of each of methane and argon. A total pressure differential
across the membrane is maintained to provide a driving force for the permeation of H2
and NH3 through the membrane. A H2-rich permeating gas which contains ammonia is
obtained on the permeate exit side of the membrane. The permeating gas is combined
with the gas in the ammonia synthesis loop and passed to the ammonia synthesis
reaction zone for conversion to ammonia. A non-permeating gas is removed from the
feed side of the separation membrane at substantially the same pressure at which the
purge stream is contacted with the separation membrane. Some benefits of Membrane
Separation are: recovers valuable hydrogen in ammonia plant purge gas, Increases
ammonia production by 4-5%, Less gas consumed per kg ammonia produced, Requires
no additional rotating equipment, Easy to operate, passive system and Ambient
temperature operation.
