Experimental investigation of a dual stage ignition biomass downdraft gasifier for deriving the engine quality gas

Abstract

The dual stage ignition biomass downdraft gasifier is the promising technology for huge tar reduction, based on two experimental approaches such as single stage and dual stage ignition. The whole unit has been tested with gradually increasing electric resistive load from 15.24 kW to 38.86 kW with a useful energy output of nearly 86.41 %. In single stage ignition approach, the hot air is only supplied at the combustion zone through a nozzle, while the two-stage ignition approach has supply of the premixed gas (hot air plus producer gas) at the pyrolysis zone for partial combustion. In dual stage ignition, the enhanced quality of producer gas comes from 56 % combustible gas with the HHV of 6.415 MJ/Nm3, while the biomass consumption rate is 59 kg/h at the maximum load with grate temperature of 1310−1360 °C. The tar content after gas cooling and cleaning unit is 8 mg/Nm3 with 15 % improvement in efficiency.