ABSTRACT
The removal of carbon dioxide produced in the shift converters is carried out using gas absorption, particularly the Benfield process. The particular absorption process is described, and mass balances are carried out on the absorber. The carbon dioxide-depleted stream from the absorber has to be passed on to the methanator where vestiges of carbon dioxide are removed using the reverse methane–steam reaction and production of methane from hydrogenation of carbon dioxide. The stream leaving the absorber has to have its temperature raised before entry into the methanator. This is done in an energy interchanger where energy is transferred between other process streams; energy balances are carried out on the equipment. The methanator has mass and energy balances carried out where the reactions in the unit are assumed to go to equilibrium. Mass and energy balances are then carried out on a low-pressure boiler feed water heater that uses energy from the methanator exit stream. The final output stream is then cooled in a separate cooler.
