Experimental investigation of poultry litter gasification and co-gasification with beech wood in a bubbling fluidised bed reactor – Effect of equivalence ratio on process performance and tar evolution

The effect of equivalence ratio on gasification of poultry litter, blend of poultry litter with beech wood and beech wood alone, was experimentally studied in a lab-scale fluidised bed reactor. Lower calorific value decreased with equivalence ratio whereas carbon conversion efficiency revealed the opposite trend. Beech wood showed both the highest lower calorific value and carbon conversion efficiency, 4.96 MJ/m3 and 91.6% respectively. Total gas chromatography-detectable tar decreased with an increase in equivalence ratio. The reduction in total gas chromatography-detectable tar was more profound in the case of poultry litter (22%). Beech wood illustrated the highest amount of total gas chromatography-detectable tar, 7.52gtar/kgfeedstock-daf at the lowest equivalence ratio, due to the higher lignin content responsible for generation of polycyclic aromatic hydrocarbons. Agglomeration occurred while gasifying poultry litter at 750 °C and at the highest equivalence ratio (0.25), whereas in the case of blend and beech wood alone all the test runs were conducted successfully.