Purified syngas feed is split between the two bulk reactors. The stream directed to the first bulk reactor mixes with the recycle gas and then enters the reaction vessel. Inside, the gases flow over the adiabatic CRG catalyst bed, where the exothermic shift and methanation reactions proceed to equilibrium.
The process stream leaving the first bulk reactor mixes with the remainder of the fresh feed that bypassed the first methanation step and enters the second bulk reactor, where again the CRG-catalysed shift and methanation reactions proceed to equilibrium.
The product from the bulk methanation stage then splits between the recycle steam and the trim methanation stage. Trim methanation also takes place across two CRG catalyst reactors, which maximises the conversion and also helps to reduce the required recycle rate at the bulk methanation stage.
After leaving the final trim methanation reactor, the methanated gas is cooled to remove water, further enriching the product gas for export.
Generally, two bulk and two trim methanation stages provide the optimum flow sheet for Davy SNG plants.
However, our methanation technology can be designed with alternative configurations to cater to different plant requirements.
Some of these alternative configurations and their applications are shown below: