A biomethanation reactor that keeps the liquid phase in a foamy state

Abstract

The bio-methanation technology is a carbon-neutral technique that utilizes hydrogen gas derived from renewable energy and recovered carbon dioxide to be supplied to anaerobic reactors, where it is converted into methane by microorganisms. The bio-methanation reaction is controlled by the gas-liquid mass transfer of hydrogen. This study focused on enhancing the gas-liquid contact area and ensuring gas residence time, particularly for high-load continuous operation, by employing a foam-type reactor to improve the efficiency of bio-methanation. The foam system was capable of stable operation at a maximum hydrogen load of 8 LH2/LV/d and maintained a methane concentration of around 94%. The hydrogen consumption rate also reached approximately 99%. By utilizing the foam state, the gas residence time in this experiment was increased by about 18 times, and the gas-liquid contact area was increased by approximately 140 times compared to the gas-stirred reactor. As a result, it is believed that hydrogen was efficiently supplied.