Biogas upgrading – technology overview, comparison and perspectives for the future

The utilization of biogas produced from organic materials such as agricultural wastes or manure is increasing. However, the raw biogas contains a large share of carbon dioxide which must be removed before utilization in many applications, for example, using the gas as vehicle fuel. The process – biogas upgrading – can be performed with several technologies: water scrubbing, organic solvent scrubbing, amine scrubbing, pressure swing adsorption (PSA), and gas separation membranes. This perspective presents the technologies that are used commercially for biogas upgradin g today, recent developments in the fi eld and compares the technologies with egard to aspects such as technology maturity, investment cost, energy demand and consumables. Emerging technologies for small-scale upgrading and future applications of upgraded biogas such as liquefied biogas are also discussed. It shows that the market situation has changed rapidly in recent years, from being totally dominated by pressure swing adsorption (PSA) and water scrubbing to being more balanced with new technologies (amine scrubbing) reaching significant market shares. There are significant economies of scale for all the technologies investigated, the specific investment costs are similar for plants with a throughput capacity of 1500 Nm3 raw biogas per hour or larger. Biogas production is increasing in Europe and around the globe, and so is the interest in the effi cient use of upgraded biogas as vehicle fuel or in other applications. The market for biogas upgrading will most likely be characterized by harder competition with the establishment of new upgrading technologies and further optimization of the mature ones to decrease operation costs. (Less)