OPTIMZED GAS SCRUBBING FOR THE EXPANSION OF BIOMETHANE PRODUCTION IN SMALL SCALE BIOGAS PLANTS – THE TRIPLE-A APPROACH (AMBIENT AMIN ABSORPTION)

The production structure of biogas is to a large extent characterized by smaller biogas plants (BGPs) using on-site CHP units. After 20 years of production under the renewable energy law (EEG), many plants look for new perspectives, and biogas upgrading to biomethane is a promising option. However, upgrading technologies are usually available for plants with a capacity of 600 m³ STP/h or more. Consequently, there is a need for scalable upgrading technologies with low costs or high revenues such as from GHG quota. The Triple-A project focuses on developing and testing a novel, robust and small-scale biogas upgrading process which uses Amino acids under Ambient conditions for chemical gas scrubbing (Absorption). The operation at ambient conditions allows a simple design with low technical requirements for components and safety and with low energy demand and high cost reduction potentials. These characteristics allow a well scalable and cost-optimized operation for upgrading capacities down to 250 m³ STP/h. In the course of the project a pilot plant was established and evaluated at a test stand at IFK. The results of the process experiments show that gas cleaning was successful with both synthetic and real raw biogas, resulting in 92.6 % methane concentration in the effluent gas. After successful completion of the test runs, the technology is put into operation at a commercial biogas plant. The process was integrated into IER RepoMod model and investigated from an economic and environmental perspective. In order to compare the Triple-A process with other upgrading technologies, the key performance indicators were evaluated.