Effect of mechanical fractionation and torrefaction on the biomass composition

摘要: In the Netherlands, green residues such as verge grass are a possible alternative to (partially) replace traditional fossil fuels. A feasible way of doing this, without large modification costs on existing power plants, is biomass co-firing. However, has high moisture content, poor grindability properties and ash which have prevented it from being directly co-combusted. Pre-treatments consisting mechanical dewatering thermal treatment (torrefaction) could greatly improve feedstock in an energy efficient way. This study firstly investigates effect fractionation composition, with focus mass losses carbohydrates, lignin, extractives inorganic matters during pressing. Secondly, experimental bench-top, batch torrefaction setup was built. test rig provide valuable data drying experiments, be used for modeling purposes operating experiences designing larger-scale plant future. Also, preliminary behavior done by analyzing products. Mechanical found quite effective handling herbaceous removes approximately 30% moisture; this pre-treatment also improves quality removing about half matters, cause slagging fouling problems combustion. Besides chemical analysis incorporating extraction, hydrolysis High Performance Liquid Chromatography (HPLC) showed that pressing had removed 10wt% carbohydrates 20wt% acid insoluble lignin. addition, studies extractive free samples proved catalytic reactivity biomass, means removal lead (slightly) higher decomposition temperature. Depending process conditions, dried will suffer 20% - 50% loss torrefaction. Results torrefied shown reduction content at different temperatures. The resulted solid product, biochar, density than primary easier store transport. makes more brittle less fibrous, would benefit fuel preparation