Semi-quantitative Risk Assessment of an anaerobic digestion process

Biogas is the most emerging industrial sector for energy production from renewable sources at National and European levels, and growing government funds favor the development of its market. From a process safety standpoint, Seveso Directive (Directive 2012/18/EU of the European Parliament and of the Council), but Biogas plants are complicated enough to require both their specific technology and an accurate risk assessment for design purposes. The number of accidents involving biogas plants has been too many to be ignored. Biogas plants are often operated wrongly, deficient in technological details and incorrectly scaled-up. Moreover, all these mistakes are repeated over and over again. Therefore, there is the pressing need for an assessment of the reliability of these plants in order to operate them safely. For this reason, a quantitative risk assessment was carried out to on a biogas production plant. Starting from event trees conventional for process industry (EU- Project ARAMIS), to the critical events, and ending with selecting the specific reference accident scenarios.