Demonstration of enhanced methane production from ammonia-pretreated biomasses in biogas plants (DEMONIAGAS)

Current biogas production in Denmark is partly based on mixing manure with other biomasses having higher methane potential. Addition of these biomasses increases the methane efficiency and thus the process profitability. However, the prices of these biomasses have increased significantly and their supply is becoming limited. The alternative option is to use lignocellulosic biomasses such us manure fibers and straw, which however need to be pretreated in order to be efficiently converted to methane in biogas plants. The existing pretreatment methods increase significantly the cost of biogas production. A previous research project (AMMONOX) clearly documented in laboratory scale that ammonia is very effective for the pretreatment of manure fibers and other lignocellulosic biomasses. The objective of the DEMONIAGAS project is to further develop and demonstrate the AAS technology (Aqueous Ammonia Soaking) in pilot scale. The project will demonstrate that the ammonia for pretreatment can be recirculated and that the technology requires no consumption of ammonia; on the contrary, it can produce a concentrate solution of ammonia that can be used as fertilizer. The project is divided into 6 work packages from the design and construction of the pilot plant, through thorough verification of the ASS technology in practice, demonstration and optimization of the technology and finally engineering of a scaled-up plant.