CO₂ utilization via a novel anaerobic bioprocess configuration with simulated gas mixture and real stack gas samples

CO₂, which is considered to be one of the major causes of climate change, has reached to critical levels in the atmosphere due to tremendous consumption of fossil fuels all over the world. In this study, anaerobic bioconversion of CO₂ into bio-methane using a novel bioprocess configuration (HYBRID bioreactor) was studied under mesophilic conditions. Varying ratios of H₂/CO₂ gas mixture and volumetric feeding rates were investigated and no additional organic matter and trace element were needed throughout the study. The maximum methane production of 19 m³ CH₄/m³ _reactor/d was achieved at a H₂/CO₂ ratio of 4:1 and feeding rate of 24 m³ gas/m³ _reactor/d. It was determined that H₂ conversion rate is about 96%. For demonstration purpose, real stack gas sample from a petrochemical industry was also tested under optimized operational conditions. No inhibitory effect from stack gas mixture was observed. This study provided an environmentally friendly and sustainable solution for industries such as petrochemical industry in order to produce extra energy while capturing their waste CO₂. Thereby, a sustainable and environmentally friendly model solution was presented for industries with high CO₂ emissions.