CO2 Methanation Characteristics over Ni Catalyst in a Pressurized Bubbling Fluidized Bed Reactor

Storing the surplus energy from renewable energy resource is one of the challenges related to intermittent and fluctuating nature of renewable energy electricity production. CO2 methanation is well known reaction that as a renewable energy storage system. CO2 methanation requires a catalyst to be active at relatively low temperatures (250-500 degrees C) and selectivity towards methane. In this study, the catalytic performance test was conducted using a pressurized bubbling fluidized bed reactor (Diameter: 0.025 m and Height: 0.35 m) with Ni/gamma-Al2O3 (Ni70%, and gamma-Al(2)O(3)30%) catalyst. The range of the reaction conditions were H-2/CO2 mole ratio range of 4.0-6.0, temperature of 300-420 degrees C, pressure of 1-9 bar, and gas velocity (U-0/U-mf) of 1-5. As the H-2/CO2 mole ratio, temperature and pressure increased, CO2 conversion increases at the experimental temperature range. However, CO2 conversion decreases with increasing gas velocity due to poor mixing characteristics in the fluidized bed. The maximum CO2 conversion of 99.6% was obtained with the operating condition as follows; H-2/CO2 ratio of 5, temperature of 400 degrees C, pressure of 9 bar, and U-0/U-mf of 1.4-3.