Ammonia

Ammonia plant concept for 300 to 600 stpd

Gas heated reformer design

Johnson Matthey’s gas heated reformer (GHR) is basically a shell and tube heat exchanger, with catalyst inside the tubes. The partially reformed gas leaving the GHR tubes flows to the secondary reformer where process air is added and further reforming takes place. Hot gases leaving the secondary reformer provide the heat for the GHR’s reforming reaction. The design is less complicated than a conventional primary/secondary reformer and especially suited for small-scale capacities.

Gas

Features of the small-scale ammonia process

  • The gas heated reformer (GHR) eliminates the need for an externally fired primary reformer, the elaborate waste heat recovery section and the consequent excess steam production.
  • Reforming section operates with air, no air separation unit required.
  • The steam system has been simplified (only medium pressure steam) to reduce capital costs.
  • Increased reliability and lower capital cost of the plant by maximizing the use of electric motors in-stead of steam turbines.
  • Low temperature desulfurization (250°C / 480°F), preheated by steam.
  • Single-stage isothermal CO shift.
  • Reliable pressure swing adsorption (PSA) eliminates the wet CO2 removal system and the separate loop purge scrubbing unit.
  • The design features a low pressure synthesis with a centrifugal compressor and uses the proven Uhde radial flow-type ammonia reactor.
  • Johnson Matthey’s Katalco 74-1 cobalt-promoted magnetite catalyst with proven long-term operating reference is used for the low-pressure ammonia synthesis.
  • No hydrogen recovery unit is required.
  • Less complexity and reduced O&M expenses. Only two operators per shift are required for the plant.
  • Opportunity for modularization reduces field construction time and the associated costs.
  • Similar energy efficiency as large-scale ammonia plants.

Reference plants

Four plants have been built based on Johnson Matthey gas heated reformer technology. Two ammonia plants operated at Severnside, UK for 20 years.Another ammonia plant, which was relocated from the USA to Australia in 2012, is still in operation. A GHR in a methanol plant in Coogee, Australia has been operating successfully since 1994.