Development of cooling and cleaning systems for enhanced gas quality for 3.7 kW gasifier-engine integrated system

Abstract

Energy from biomass based gasifier-engine integrated systems are becoming more popular for power generation applications in rural and urban driven societies. The quality of producer gas from the down draft gasifiers plays a significant role in power generation aspects. During gasification, tar is produced and its magnitude depends on the type of gasification process and biomass feedstock used which can vary from biomass to municipal solid waste (MSW) available. The pollutants generated from gasification include particulate matter, tars, and char and acid gases. A major challenge for commercializing the gasification process is to reduce tar. In order to address these tar related problems a cleaning and cooling system has been developed in house that facilitates tar removal to acceptable levels tolerated by the internal combustion (IC) engine and meets emission standards as well. The main objective of the present work is to reduce tar level and develop control strategies for improving the performance and emission of diesel engines. Results showed that the brake thermal efficiency of the dual fuel engine used was increased by 2-4% and tar was reduced from 325 mg/Nm³ in the gasifier to 60-50 mg/Nm³ entering the engine. In addition, the emission levels such as hydrocarbon, carbon monoxide were reduced comparatively with developed cooling-cleaning system provided in the conventional gasifier-engine system. The biomass consumption rate was 40kg/h. Air and gas flow rates were measured to be 18.8 m³/h and 20.12 kg/h respectively. The temperature of the gas after developed cooling and cleaning system was found to be 34 °C.

Keywords: Dual fuel engine, cooling-cleaning system, Rice bran oil methyl ester, tar, performance, emissions