The aim of the project consists in the development of a new process design for the integrated use of raw materials replacing conventional biogas reactors (hydrolysis and methane generation in separate reactors). With this concept a coupled raw material and energy use of biogas substrates is pursued, contributing to a sustainable and complete exploitation of agricultural residues. A cascade approach creates a higher added value providing organic acids as platform chemicals. With this bio-based approach, the project strengthens agricultural biogas production and an environmentally friendly supply with basic chemicals for the chemical industry as a substitute for petrol-based products.
The Optigär method was compared to a model 250 kWel biogas reference plant. For optimum feedstock variants with equal biogas and additional organic acid yield, indicative costs were assessed. For grass, additional costs of 60% and for corn of 70% resulted. The extra costs are to be compensated via revenues from organic acids product sales. Relevant market options are found in the feed supplement industry for example. Corresponding GHG emissions due to increased feedstock demand rose by 35% for the corn and 21% for the grass variant.