Biogas as an energy vector

Main Biogas Upgrading Technologies

“…The choice of the appropriate treatment and purification technology depends on factors such as the amount of biogas produced and its composition, the level of purification required and costs, namely capital and operational expenditure (CAPEX and OPEX) [3]. In biomethane requirements, a combination of processes is used, as no technology can remove all contaminants from biogas [1].…”

“…The high degree of biogas purification treatment to obtain biomethane requires the use of more complex and expensive techniques, as they allow the removal of contaminants more efficiently. This upgrading is carried out through treatment and purification processes, involving technologies to remove the other gases present in the biogas, separating the CH 4 and thus increasing its calorific value [1].…”

“…To avoid an efficiency reduction of the process, biogas components, such as H 2 O and H 2 S, must be previously removed because they are irre-versibly adsorbed on the adsorbent solids. However, other contaminants present in biogas, such as N 2 and O 2 , can be removed through this process [1].…”

“…The water regeneration is carried out, in a first phase (flash tank), with the recovery of the absorbed biogas, being recycled through the injection at the biogas inlet. The second phase of regeneration takes place in a second column (stripper) through a countercurrent with air, operating under atmospheric pressure [1]. This process is similar to pressurized water scrubbing and is a chemical absorption technique where the solution absorbs the CO 2 present in the biogas, through a chemical reaction between the amine and CO 2 (Figure 5).…”

“…Biogas can be produced in landfills and anaerobic digestion units. It results from the release of gases when an organic waste is decomposed in the absence of oxygen [1]. Biogas can also be produced through thermal pyrolysis and gasification processes.…”