Fraunhofer Institute for Ceramic Technologies and Systems IKTS
Biomass Technologies and Membrane Process Engineering
Björn Schwarz – project manager
Telephone: +49 (0)351 2553-7745
Dr. Jan Hari Arti Khalsa – Projektleiter
Telefon: +49 (0)341 2434-396
Martin Hülsmann – Projektleiter
Telefon: +49 (0)5439 9403-11
Final report only available in German
The project focuses on the energetic utilization of poultry manure and straw based on biogas production. In addition to the energy balance (incl. logistics) especially the material potential of the resulting digestate (fertilizer and fuel) is considered or developed.
On the one hand the objective is to proof the practical feasibility of straw-based energy pellets in a large-scale biogas plant and on the other hand further improvement of the energy demand in the tightly focussed treatment of fermentation residues into valuable materials and process water. Furthermore, in addition to the production of fertilizer products a fuel to be produced from fermentation residues which is suitable for direct use in boilers.
At the end of the project design parameters are available for the entire process chain for large-scale implementation.
IKTS analyses and evaluates all input and output flows of the following process stages: substrate pretreatment, fermentation and digestate treatment. Continuous experiments are carried out in the laboratory with regard to the long-term stability with the use of condensates of the evaporation step and the use of straw pellets with sodium hydroxide. Furthermore, the IKTS works conceptually and experimentally in the areas of digestate separation and improvement of the combustion properties.
DBFZ characterises the resulting digestate with regard to their fuel properties. Additional purification steps for digestate are applied in order to minimize the emissions occurring during the combustion. Furthermore small-scale combustion tests up to 100 kW are carried out with complete analysis.
Main objectives are minimizing energy consumption and amounts to dispose as well as maximizing value creation through production of valuable materials out of the digestate treatment. For this purpose extensive tests for dewatering before the evaporator stage are organized in practically relevant scale (in particular the removal of fines). In addition, tests are carried out and will be evaluated for the efficient drying of the various intermediates of the digestate.
GM Biogas operates a 2.4 MW biogas plant with three parallel fermenters. Within the project the amount of supplied corn silage of one fermenter will be changed into straw-based biogas pellets produced in the project.
A demonstration experiment for the production of 250 t straw-based biogas pellets is designed and realised by ATS. That includes organizational and security measures. ATS enables the manufacture of large quantities of pellets from separated, dried and optionally conditioned digestate.
The A.P. Bioenergy GmbH deals with the optimization and further development of the combustion step concerning the thermal utilization of untreated and treated digestate. The combustion emissions are significantly reduced by setting and adjusting various parameters. Combustion tests will take place in a pilot plant with up to 400 kWth.
REGEB is responsible for the execution of evaporation tests of digestate liquid phase at industrial scale. For this a four-level system is used. The overall efficiency of the plant is to be increased by supplementing of a pre-degassing step.