Production Method
Kellogg high capacity single-train plant
Reactants and Products
÷ Raw material feed is natural gas and air.
÷ Products are ammonia and natural gas leftovers.
Main Steps
÷ Feed Preparation: natural gas is compressed and desulfurized
÷ Reforming: natural gas is mixed with steam and air to make crude syngas
÷ Syngas Cleanup: purified streams of nitrogen and hydrogen are produced and prepared in correct stoichiometric ratio
÷ Syngas Compression
÷ Ammonia Synthesis and Recovery
Steps and Unit Opps
÷ Feed Preparation
o Natural gas compressor and air compressor (not needed if supply line is high pressure)
o Sulfur removal (usually by hydrogenation, details out of our scope)
÷ Reforming
o Primary reformer (furnace)
o Secondary reformer (refractory lined vessel with catalyst bed)
÷ Syngas Cleanup
o High temperature and low temperature shift converters; packed columns (converts CO to CO2)
o Cooling and knockout; heat exchangers and stripper (water removal)
o Absorber-stripper system (CO2 removal)
o Methanator (convert residual carbon oxides back to methane)
o Drier (remove trace water)
÷ Syngas Compression
o Centrifugal compressor (steam turbine driven); multistage with inter-stage cooling
÷ Ammonia Synthesis and Recovery
o Reactor: ammonia converter (quench converter)
o Refrigeration to condense ammonia liquid as product
o Small gas purge removes remaining inerts
Resource:
Tim Eggeman.
"Ammonia". Kirk-Othmer Encyclopedia of Chemical Technology. October 18, 2001.
John Wiley & Sons: Copyright 2001.