Biogas Valorisation to Biomethane for Commercialisation in South Africa: A Review

Abstract

Biogas consists of mainly methane, as a source of energy, and impurities such as carbon dioxide, hydrogen sulphide, water, and siloxanes. These impurities, such as hydrogen sulphide, reduce the biogas energy content and corrode equipment that store, transport, or utilise biogas. Several reviews on upgrading biogas to biomethane have been published, but minimal focus has been put on upgrading biogas for commercialisation in South Africa. Thus, this study reviewed biogas upgrading techniques in South Africa to put together information on activities and experiences on biogas valorisation to enhance the chances for different stakeholders to learn and build on from local experiences. To capture all relevant information, literature from the past 10 years was retrieved from online databases and government, municipality, and companies’ websites and institutional repositories. The review covered the sorption, separation, and in situ techniques that are globally used for upgrading biogas. The status of the biogas sector and the upgrading activities that occur in the country with their cost, energy, and environmental impacts were given in detail. It is estimated that a total of 3 million Nm3d−1 of biogas can be produced in the country from biogas substrates. Thus, researchers and entrepreneurs are encouraged to collaborate to utilise the abundant resources used for biogas production to enhance the commercialisation of biomethane.

Keywords

• biogas
• biogas valorisation
• biogas upgrading
• biomethane
• sorption
• separation