KLAWIR

Small anaerobic plants for the utilization of farm manure (KLAWIR)

Topic

The use of lignocellulosic residues such as horse manure, landscape maintenance material or straw from agriculture represent a new utilization path for biogas production. Since these substrates usually have high dry matter and lignin contents, special pre-treatment is required for utilization in the biogas plant. Without this pre-treatment, the fermentation substrates are not completely and slowly degraded. This is accompanied by low methane yields and a resulting uneconomical operation. Furthermore, process-related problems, such as increased floating layers and a higher stirring effort in the fermenter, arise without a pretreatment. Mechanical pretreatment by means of a ball mill can accelerate the kinetics of the degradation and gas formation process and increase the resulting methane yield of unused residues. Additionally, the process reliability and economic efficiency are enhanced. Therefore, it contributes to a flexible and sustainable electricity production.

Goals

The aim of the project is to further develop the ball mill and to optimize its design and process technology so that lignocellulosic substrates can be optimally processed for flexible biogas production. As a result, operational as well as economic advantages can be expected. This would make the use of by-products and residues from agriculture in biogas plants attractive and thus replace a part of the energy crops cultivated for biogas production. Furthermore, it would mean an improvement in the CO2 footprint of the entire process chain and contribute to the sustainability of biogas plants.

Project tasks of the State Institute

The State Institute for Agricultural Engineering and Bioenergy is coordinating the entire research project. In close cooperation with the project partners, a pilot-scale plant is planned and built at the research facility at the University of Hohenheim's "Unterer Lindenhof". The state institute will apply for planning permission and prepare the mass and heat balance. The optimization of heat recovery is also included in the planning. The corresponding components for the pilot plant are then designed and prefabricated. The entire construction phase is supervised by the state institute. After commissioning, the process will be scientifically monitored in a one-year test operation in order to record the biological process stability, the methane yield potential and the potential for reducing greenhouse gases. In addition to the technical and ecological aspects, possible cost reduction measures will also be taken into account. To ensure a successful transfer of knowledge into practice, a concept for the market launch of the process will be developed during the project period.