Catalytic reforming of nitrogen-containing volatiles evolved through pyrolysis of composted pig manure

The pyrolysis of pig compost was performed in a two-stage fixed-bed reactor to determine the effects of decomposition temperatures and catalysts (i.e., transition-metal and non-transition-metal catalysts) on carbon and nitrogen conversions. The secondary decomposition was investigated at different temperatures from room temperature up to 750 °C. Then the effects of various catalysts were investigated at 650 °C. Approximately 60% of the carbon and 80% of the nitrogen in the pig compost were converted into volatiles during pyrolysis. Conversion of carbon and nitrogen species in tar into gas, and the evolution undesirable NH3 and HCN without catalyst increased with increasing decomposition temperature. Transition-metal catalysts showed excellent activity for conversion of condensable volatiles into gas and NH3 and HCN into N2. Although non-transition-metal catalysts had moderate activity for the conversion of volatiles into gas and negligible activity for the conversion of NH3 into N2, dolomite can provide liquid fuel with negligible amount of nitrogen species.