Experimental analysis of dual-stage ignition biomass downdraft gasifier based on various gasification media for the generation of high-quality producer gas

Abstract

A dual-stage biomass ignition downdraft gasifier has been set-up with the four experimental approaches such as hot air ignition, hot air plus producer gas ignition, oxygen ignition and oxy-steam ignition approach. The experimental unit has been tested at electrical resistance loads of 15.24 kW, 23.62 kW, 27.43 kW, 32 kW and 38.86 kW. This unit provides a useful energy output of nearly 95.37 % in oxy-steam ignition approach at maximum load. The gasification medium is provided at the combustion zone as well as in pyrolysis zone for the complete and partial combustion in the respective regions through the installed nozzles. In the oxy-steam ignition approach, the enhanced quality of producer gas generates, which contains 94 % combustible gases in the producer gas. The Higher Heating Value (HHV) is 12.317 MJ/Nm3, whereas the biomass consumption rate is attained 21 kg/h at the highest resistive load with 1430–1590 °C grate temperature under the oxy-steam ignition approach. The proportion of tar is obtained 0.2 mg/Nm3 after the syngas cooling and cleaning arrangement with moisture content of 6 %, while a significant improvement of 21.26 % has been noted in efficiency under the oxy-steam ignition approach.