Potential Processes for Simultaneous Biogas Upgrading and Carbon Dioxide Utilization

Abstract

In this chapter, potential processes for coupling biogas upgrading to obtain bio‐methane with carbon dioxide capture and utilization are presented. Bio‐methane is an attractive source of clean energy, and its utilization as fuel is becoming more and more important during the past years. Biogas comes from the anaerobic digestion of organic matter and it is mainly composed of methane and carbon dioxide. Thus, an upgrading to remove carbon dioxide and obtain bio‐methane is necessary. The upgrading stage can be carried out by several technologies such as water‐organic physical scrubbing, chemical absorption, adsorption, cryogenic separation, and membrane processes. Some of these technologies have proved to be industrially feasible. Nevertheless, there is a need to improve the economic viability of these processes placing bio‐methane as a competitive green energy against traditional fossil fuels. One way to do it is to use the captured carbon dioxide as a raw material in other industries. Many applications for carbon dioxide are reported in the literature such as direct utilization in food–drink industry, chemical production from carbon dioxide, mineral carbonation – carbonates production, enhanced oil recovery, supercritical solvent, and dry ice production. Nevertheless, the majority of these applications have a demand that is very low in comparison with the carbon dioxide production worldwide. Inasmuch, carbon dioxide coming from biogas upgrading has a relative range that can fit into carbon utilization technologies. In this chapter, biogas upgrading technologies are coupled with carbon utilization technologies as potential processes already described in the literature or as potential ideas that can be further developed.