Optimisation Strategy of Carbon Dioxide Methanation Technology Based on Microbial Electrolysis Cells

Abstract

Microbial Electrolytic Cell (MEC) is an electrochemical reaction device that uses electrical energy as an energy input and microorganisms as catalysts to produce fuels and chemicals. The regenerative electrochemical system is a MEC improvement system for methane gas produced by biological carbon sequestration technology using renewable energy sources to provide a voltage environment. In response to the influence of fluctuating disturbances of renewable electricity and the long system start-up time, this paper analyzes the characteristics of two strategies, regulating voltage parameter changes and activated sludge pretreatment, on the methane production efficiency of the renewable gas electrochemical system. In this system, the methane production rate of regenerative electrochemical system is increased by 1.4 times through intermittent boosting start-up strategy; based on intermittent boosting, the methane production rate of regenerative electrochemical system is increased by 2 times through sludge pyrolysis pretreatment start-up strategy, and the start-up time is reduced to 10 days. Meanwhile, according to the simulation test results of power input fluctuation and intermittency, the stability standard deviation of its system operation is 75% of the original one, and the recovery rate is about 1 times higher. This study can provide a theoretical basis and technical reference for the early industrial application of microbial CO2 methanation technology based on renewable energy.