According to the estimates given by the International Energy
Agency, global gas demand will grow from 3:4 trillion m3 in 2012
to 5:4 trillion m3 in 2040 [1]. This is partly because replacing coal
with natural gas in power production is seen as attractive due to
the lower carbon dioxide ðCO2Þ emissions of the latter. However,
the regulation of CO2 emissions is becoming stricter as, for exam-
ple, the European Union has set a target of a 40% reduction in
greenhouse gas emissions by 2030 compared to the levels in
1990 [2]. Consequently, the CO2 emissions has to be reduced also
in the use of natural gas [3,4].
The thermal decomposition of methane (TDM) is an endother-
mic reaction where methane is thermally converted to solid car-
bon, gaseous hydrogen, and traces of higher hydrocarbons. Eq.
(1) presents a simplified reaction equation of TDM [5].
CH4 ! C þ 2H2 DH0
The equilibrium curve of TDM reaction presented, for example,
in [6] shows that the degree of methane conversion increases with
temperature. However, temperatures above 1200 C are required
to achieve a nearly complete conversion when no catalyst is applied.