Project meeting of STEP at the site of the company ATS - Agro Trading & Solutions in Hardegsen (Photo: DBFZ)

Biogas Biomass furnace

Project ID 03KB038

SpentGrain - Optimized energetic utilization of wet waste (Brewery’s Spent Grain) through the combination of biological, mechanical an thermal processes

Biomass farm Achental (Photo: DBFZ)


  • 01.10.2009 – 30.09.2011


Technical University Munich
Lehrstuhl für Rohstoff- und Energietechnologie
An der Maxhütte 1
92237 Sulzbach-Rosenberg

Dr.-Ing. Wolfgang Mayer – project leader
Telephone: +49 (0) 94 21 - 18 71 06
E-mail: wolfgang.mayer‍@‍

Dipl.-Ing. Samir Binder – contact person
Telephone: +49 (0) 9661 908-410
E-mail s.binder‍@‍


Associated partners

Cooperation partners



Results are only available in German.


The high fiber fraction disturbs the fermentation process. In thermal processes, the protein (NOx- and SO2-emissions) and the high water content are the disturbing factors. Drying Brewery’s Spent Grain is excluded for energy reasons. The separation of the easy biodegradable substances in combination with water is realized in a screw press, in addition the effect of additives like tensides, acids or enzymes will be researched too. The suitability of the pressed water for a biogas plant will be demonstrated. The fibers can directly be fired in a combustion plant. Due to the fact that the energy content of Brewery’s Spent Grain is not high enough for the full energy supply of a brewery (max. 50 %), the combustion system must be adapted to biogas and other possible biomasses too.


The project aim is the combination of fermentation and combustion process for wet, fiber biomass, exemplary researched with Brewery’s Spent Grain (80 % water).


  • Separation of the protein content during dewatering process, add-on additives, size of the sieve, diameters and pitches of the screw extrusion press on dewatering and separation rate
  • Degradation of protein fraction with brewery waste water in a fermentation reactor
  • Combustion of the fiber fraction in a cyclone firing plant
  • Pre planning of a demonstration plant
  • Calculation and evaluation of climate protection and economic effects


  • Separation of biodegradable and combustible fractions of Brewery’s Spent Grain
  • Demonstration of fermentation / combustion


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