Poultry Litter Gasification in a Fluidized Bed Reactor: Effects of Gasifying Agent and Limestone Addition

Abstract

Air and air-steam gasification of poultry litter was experimentally studied in a laboratory scale bubbling fluidized bed gasifier at atmospheric pressure using silica sand as the bed material. The effects of equivalence ratio (ER), gasifier temperature, steam-to-biomass ratio (SBR), and addition of limestone blended with the poultry litter, on product gas species yields and process efficiency, are discussed. The optimum conditions (maximum carbon conversion, gas yield, heating value, and cold gas efficiency) were achieved at an ER 0.25 and 800 °C, using air (SBR = 0) and poultry litter blended with 8% w/w limestone, yielding a product gas with a lower heating value (LHV) of 4.52 MJ/Nm3 and an average product gas composition (dry basis) of H2: 10.78%, CO: 9.38%, CH4: 2.61, and CO2: 13.13. Under these optimum processing conditions, the cold gas efficiency, carbon conversion efficiency, and hydrogen conversion efficiency were 89, 73, and 43% respectively. The reported NH3 measurement at an ER of 0.28 and 750...