Process description: Natural gas after purification is sent to steam methane reformer which is a fired tube furnace with catalyst filled tubes (SMR) where gas mixture (feed NG + steam) is passed through. In the SMR, feed is partially converted into syngas and this mixture is sent to secondary reformer in which stoichiometric required N2 will be added in the form of pure air. The heat required for endothermic reforming reactions is supplied by fuel burning and the produced flue gas is vented to atmosphere. In the secondary reformer, the remaining unconverted feed (NG) is converted to syngas by steam and O2. The final product gas leaving the secondary reformer is sent to shift reactors after removing the excess heat in the boilers. The gas leaving the shift converters is sent to CO2 removal section where CO2 is removed and stripped off as process CO2.
Syngas leaving CO2 removal section is further ultra-purified to bring CO and CO2 levels to ppb as these components are poison to NH3 synthesis catalyst.
The ultra-pure syngas (H2/N2: 3:1) is pressurized to high pressure and heated in a gas-gas heat exchanger and fed to ammonia converter loaded with Fe promoted catalyst. Ammonia is synthesized in the ammonia converter and the product gas is sub-cooled to separate the NH3 from the unconverted synthesis gas.
The unconverted synthesis gas is recycled back to the ammonia synthesis converter and separated NH3 will be sent as product to end user.
