Pretreaments of Chinese Agricultural residues to increase biogas production

Sammanfattning: Development of biological conversion of lignocellulosic biomass to biogas is one approach to utilize straw comprehensively. However, high lignin contents of lignocellulosic materials results in low degradation. The main aim of this study was to investigate the appropriate pre-treatment to increase biogas production from Chinese agricultural residues. In this study, Chinese corn stalk, rice plant and wheat straw were evaluated as substrates by applying three different pre-treatments. The investigated pre-treatment were mechanical pre-treatment (cut whole straw into 1-1.5cm) combination of thermal and alkali pre-treatment (1M/L NAOH, 80℃,15 hours) and biological pre-treatment(enzymes provided by Scandinavian Biogas Fuels AB). Biogas production of these substrates was evaluated by batch digester; Sewage sludge from Nykvarn treatment plant and current digesters (Scandinavian Biogas Fuels AB )was the co-digestive substrate which seeded in batch with straw of all pre-treatments. The results indicate that at least 50% of organic contents in Chinese agricultural residues could be converted to biogas by these pre-treatments. The optimizing biogas yield is achieved from Chinese corn stalk with combination of thermal and alkali pre-treatment, Chinese rice plant and wheat straw from pre-hydrolysis pre-treatment respectively .Chinese wheat straw has the most biogas potential from combination of thermal and alkali pre-treatment.