Methanation is the reaction by which carbon oxides and hydrogen are converted to methane and water. The reaction is catalysed by nickel catalysts. In industry, there are two main uses for methanation, to purify synthesis gas (i.e. remove traces of carbon oxides) and to manufacture methane.
Methanation for synthesis gas purification
Methanation is the final stage in the purification of synthesis gas and most modern ammonia plants plus some older hydrogen plants use the simple and convenient methanation reaction to remove traces of carbon oxides from the process gas.
Methanation for SNG
In substitute natural gas (SNG) manufacture, carbon oxides and hydrogen from alternative hydrocarbon sources are converted into methane. Johnson Matthey offers the CRG methanation catalyst range for the this duty. CRG catalysts provide good thermal stability and resistance to residual poisons in the gas to achieve a long life while giving the flexibility to operate over a wide temperature range resulting in high efficiency and heat recovery.
Methanation for ethylene production
Hydrogen produced as a by-product of ethylene production contains 500 to 5,000 ppm carbon monoxide. The concentration of carbon monoxide must be reduced to less than 10 ppm prior to use in reactors containing palladium or platinum based catalysts.
Johnson Matthey manufactures a range of oxidic and pre-reduced KATALCO methanation catalysts for ethylene production.