Energetic conversion of European semi-natural grassland silages through the integrated generation of solid fuel and biogas from biomass: energy yields and the fate of organic compounds

Abstract

Twelve European habitat types were investigated to determine the influence of the IFBB technique (integrated generation of biogas and solid fuel from biomass) on the fate of organic compounds and energy yields of semi-natural grassland biomass. Concentration of organic compounds in silage and IFBB press cake (PC), mass flows within that system and methane yields of IFBB press fluids (PF) were determined. The gross energy yield of the IFBB technique was calculated in comparison to hay combustion (HC) and whole crop digestion (WCD). The IFBB treatment increased fibre and organic matter (OM) concentrations and lowered non-fibre carbohydrates and crude protein concentrations. The PF was highly digestible irrespective of habitat types, showing mean methane yields between 312.1 and 405.0 LN CH4 kg(-1) VS. Gross energy yields for the IFBB system (9.75-30.19MWh ha(-1)) were in the range of HC, outperformed WCD and were influenced by the habitat type.

Keywords: ADF; ADL; Bioenergy; Biogas; CF; COD; CP; DM; EE; FM; HC; HHV; IFBB; MF; NDF; NFC; OM; PC; PF; Semi-natural grassland; VS; WCD; XA; a.s.l.; above sea level; acid detergent fibre; acid detergent lignin; chemical oxygen demand; crude ash; crude fibre; crude protein; dry matter; ether extract; fresh matter; hay combustion; higher heating value; integrated generation of solid fuel and biogas from biomass; mass flow; neutral detergent fibre; non fibre carbohydrates; organic matter; press cake; press fluid; volatile solids; whole crop digestion.