Chemical looping combustion and gasification of swine manure with a Cu-Based oxygen carrier

The thermochemical conversion of swine manure by using Chemical Looping Combustion (CLC) and Chemical Looping Gasification (CLG) is an interesting option to obtain bioenergy and solve some environmental issues related to this waste. In this work, experimental tests using swine manure as fuel and a Cu-based oxygen carrier (14 wt% CuO) in a 0.5kWth continuous unit have been performed. For CLC conditions, the effects of the temperature (800-900 degrees C) and the fluidization agent (CO2 or steam) on the combustion and CO2 capture efficiencies were evaluated. In general, high combustion (97-99 %) and CO2 capture (87-99 %) efficiencies were achieved, which improved by increasing the operating temperature. For CLG conditions, the effect of the oxygen-to-fuel ratio (lambda = 0.2, 0.3 and 0.4) on the gas product distribution, CO2 capture efficiency and tar composition was studied using steam and CO2 as fluidizing agents at 900 degrees C. The CO2 capture potential improved by increasing the oxygen-to-fuel ratio. Regarding the tar distribution, naphthalene was the main product followed by benzene, acenaphthylene, indene and phenanthrene. Additionally, for both processes, CLC and CLG, the distribution of nitrogenous compound emissions (N2, NH3, N2O, NO2 and NO) was analyzed. It was observed that the N-swine manure was mainly converted into inert N2.