Integrated Generation of Solid Fuel and Biogas from Biomass

The PROGRASS® technique aims at dividing the grassland silage into a solid part for combustion and a liquid fraction for biogas production. The extraction of minerals and easily digestible compounds into the liquid significantly improves the combustion performance of the solid fraction (press cake) which is converted in a storable biofuel. In addition, the press fluid is a suitable substrate for biogas production.

Procedural Design

• Silage is first mashed with 40°C warm water

• Separation of mashed biomass into a solid, fibrous fraction (press cake) to be used as a solid fuel, and a liquid, biologically convertible fraction (press fluid) for the production of biogas and electricity.

• Biogas production from the press fluid and its use in a combined heat and power plant (CHP) to produce electricity and heat.

• Drying of the press cake by the waste heat of the CHP and supply of a fuel with improved combustion characteristics compared to the untreated biomass.

• Prevention of unused waste heat from CHP through year-round drying of the press cake.

• Digestates can be used as valuable fertiliser containing a lot of mineral nutrients.