Production of synthetic natural gas by means of a catalytic nickel membrane

In this study, a new method of methanation was developed using a catalytic nickel membrane for synthetic natural gas (SNG) production. The methanation reaction is exothermic, so heat that is generated should be removed from the reactor to prevent the methane yield from being reduced and to minimize deactivation of the catalyst due to thermal stress at hot spots. Since the catalytic nickel membrane was made by uniaxial-pressing and thermal treatment of nickel powder, it could readily remove heat from the reactor. Methanation tests conducted at various temperatures, residence times and pressures revealed that the CO and H2 conversions increased with increasing temperature and pressure and reached a maximum value of 99 and 80% at a temperature, residence time and pressure of 350 °C, 94 ms and 280 kPa, respectively. The CH4 increased with increasing pressure and reached 96% at a temperature of 350 °C, residence time of 94 ms and pressure of 280 kPa. The temperature gradient between the top and bottom of the membrane was within 20 °C, indicating that heat was reliably transferred and re-distributed throughout the thin (∼2.0 mm) metal membrane. From the methanation tests, a new reactor could be designed for high exothermic reactions.