Chemical methanation

Chemical methanation is the conversion of carbon monoxide and carbon dioxide to methane through hydrogenation in the presence of a catalyst, particularly nickel, due to its high activity, selectivity, low cost and abundance. For the methanation, a source of carbon is needed, such as carbon monoxide (CO) in the syngas from gasification or pyrolysis (e.g. biomass gasification), or carbon dioxide (CO2) from exhaust gases from combustion (industry, power generation), fermentation, anaerobic digestion (biogas) or captured directly from the air. CO and CO2 methanation processes have been investigated for more than 100 years, originally to remove CO in ammonia production, as it acts as a catalyst poison, and to purify hydrogen at refineries. Afterwards, CO methanation gained importance during the oil crisis in the late 1970s, to produce a natural gas substitute using syngas from coal gasification. CO2 methanation process developments primarily rely on CO methanation research with basic studies performed in the 1980s. Even though methanation has been applied by industry for many years, an optimisation of state-of-the-art methanation technologies is needed, particularly for direct CO2 methanation. Research seeks to improve the methanation catalysts, varying gas compositions, and to enhance process flexibility associated with variable production of hydrogen.