Evaluation of Tar and Particulate matter in Producer gas for Different Equivalence Ratio in Downdraft Gasifier

Abstract

Gasification is a process which converts carbonaceous feedstock into producer gas. Tar and particulate matter (PM) are the major pollutants from gasifier which may be harmful for end use activities such as gas turbine and IC engine. The main objective of this study was to investigate the performance of gasifier with different equivalence ratio (ER). Influence of the equivalence ratio on temperature profile, fuel consumption rate, gas composition, gas calorific value, cold gas efficiency, tar and particulate matter were carried out in this study. Seven different equivalence ratios viz. 0.26, 0.30, 0.35, 0.37, 0.39, 0.41, 0.43 were selected for experimental work. In this work, lignite – sawdust briquette (70:30 w/w) was selected as a feedstock for experimentation on 10 kWe downdraft gasifier. It was observed that fuel consumption and gas yield increased by increasing ER. CO yield was found 18-19% between ER 0.37-0.42. CH4 yield was decreasing with increasing of ER. Fuel consumption and Gas yield were increased 0.54 – 11.1 kg/hr and 1.34 – 26.82 m3/hr respectively. It was observed that H2 and CO2 yield increased with increment of ER. Gas calorific value and cold gas efficiency were varying 942-1170 kcal/m3 and 58-70% respectively. Tar was varying from 565 to 516 mg/m3. Particulate was observed between 47-57 mg/m3. As ER was increased, tar and particulate was reduced. Optimum ER was observed at 0.43 which is the general conclusion from this study.