Upgrading of biogas using bottom ash from woodfuels

Last changed: 05 July 2011

The objective of the study was to study absorption of carbondioxide from biogas with bottom ash from incineration of woodfuels and Salix in order to reach vehicle fuel quality (97 % methane) and based on the results, suggest systems for upgrading of biogas with ash.

The overall goal was to facilitate cost effective upgrading of biogas at farm-based biogas plants. The specific goal was to present basic data, which could show the prerequisites and limitations with such systems. Combined heat- and power production is currently the most economic interesting alternative. However, upgrading to vehicle fuel can increase the value of the gas, but the costs have to be reduced.

Bottom ash from woodfuels has characteristics that are suitable for carbon dioxide absorption. Thus, a residue with low value existing in large amounts would therefore have potential to be used for upgrading also at low gas flow rates.