CO2 Generation from Biogas: A Comprehensive Study on Rate Determination, Upgrading Techniques, and Environmental Implications

This study investigates carbon dioxide (CO
2
) generation from biogas during the initial eight days of anaerobic digestion (AD) using cow dung digestate. Employing Archimedes’ principle, the volume of CO
2
produced is measured, revealing a consistent increase in flow rate over the experimental period. The findings underscore the importance of improving biogas quality by addressing CO
2
content through techniques like chemical absorption, cryogenic separation, and membrane-based filtering. The research underpins biogas upgrading for transportation, emphasizing CO
2
removal before using raw biogas as vehicle fuel. Various biological processes, including microalgae and methanogenic bacteria, are explored for efficient CO
2
extraction during biogas upgrading. The study categorizes CO
2
capture into pre-combustion, post-combustion, and oxy-fuel combustion, highlighting their relevance in different usage scenarios. Methanation, a chemical process converting CO
2
into methane (CH
4
), is discussed for its potential to increase overall CH
4
production. In-situ and ex-situ methanation approaches are presented, along with a detailed methodology for determining the rate of CO
2
generation during biogas production. In conclusion, this research contributes valuable insights into addressing CO
2
in biogas production to enhance its environmental performance. The study advocates for the adoption of CO
2
capture and utilization technologies, emphasizing their role in advancing sustainable energy solutions for a greener future.