Thermal pre-treatment of cellulose rich biomass for biogas production :

Abstract: Anaerobic digestion is one possible method to produce bioenergy from cellulose rich materials but the process techniques still need refinements to facilitate the production process. In this work the biogas potential from six different plant materials was evaluated and what effect a thermal pre-treatment had on this potential. The biogas production was determined in a batch experiment model with small biogas reactors. The tested substrates were oat straw, meadow grass, aspen, spruce and wet grain residue from two different ethanol production plants in Sweden, all of which were thermally pre-treated with one or two pre-treatment setups and compared in production with untreated materials. Results show that thermal pre-treatment does have an effect on the biogas production but that different materials need different thermal pre-treatment parameters. The experiment also showed that the particle size of the plant material can have an equally large effect on the biogas production as the thermal pre-treatment. Smaller particles give rise to a higher methane production. Of the tested materials the untreated wet grain residue from spirits production showed both the highest degradation rate and total biogas production whereas the thermally pre-treated spruce had the lowest production.