Study on Performance and Energy Balance of a U-Shape Flow Biomass Gasification System

This research explores biomass gasification for power generation in rural areas of developing countries, utilizing a ۲۰ kW U-flow-shaped gasification system developed at Ashikaga University. While small-scale power systems typically rely on reciprocating or modified diesel engines, which face issues due to tar produced by biomass gasifiers, this study employed a piston-less rotary engine. Performance evaluations were conducted at various engine speeds and gasifier operational modes, demonstrating continuous power generation for approximately six hours. Improved maintenance of rotary engines could benefit rural users, with potential efficiency gains through thermal energy recovery, although tar filtration needs enhancement. The experimental findings reveal continuous power generation for approximately six hours under both operational conditions, with the closed-top operation outperforming the open-top counterpart in terms of power output. However, control over power output and gasifier temperatures is more straightforward in the open-top operation. Gasifier performance was assessed based on fuel consumption rate and system efficiency, with consumption rates varying by rotary engine speed, measuring ۲.۰ kWh/kg at ۲۸۰۰ rpm and ۲.۳ kWh/kg at ۳۲۰۰ rpm, and ۲.۹ kWh/kg at ۳۶۰۰ rpm. Cold gas efficiency of the U-shaped gasifier was ۶۳.۴%, and energy conversion efficiency reached ۹.۴% at ۲۸۰۰ rpm operation. At ۳۲۰۰ rpm operation, cold gas efficiency improved to ۷۹.۸%, but energy conversion efficiency decreased to ۷.۳%. The rotary engine's energy conversion efficiency was lower than that of a gas engine. Nonetheless, if the rotary engine reduces maintenance needs, it could benefit rural users. Efficiency can be improved through thermal energy recovery.

Keywords:

Biomass gasification , produced gas , Power Generation , Fuel consumption , Efficiency