Cattle dung conversion to syngas: solar photovoltaic integrated gasification system

Partial oxidation of dried cattle dung cannot achieve temperatures necessary for endothermic reduction reactions in autothermal gasification, because of lower fixed carbon (FC) content and higher volatility of feedstock. This study comprehends a simplified and viable allothermal gasification of cattle dung in an integrated system. Solar photovoltaic (PV) induced air gasification of dried cattle dung was carried out in a small-scale tubular furnace, equipped with controlled operating systems. Characterization of cattle dung showed that it had a higher heating value (HHV) of 16 ± 0.01 MJ/kg, volatile content of 63% ± 1%wt, and FC of 15 ± 1%wt. Gasification was performed at variable power supply levels (W) of the solar PV system and corresponding temperatures with varying air–fuel equivalence ratios (ER = 0.21–0.3). The optimal fractions of hydrogen (13.26 ± 0.95%), carbon monoxide (14.39 ± 1.2%), and methane (2.15 ± 0.5%) were achieved at 1100 W, 800 °C, and 0.26 ER. The HHV of syngas was 4.89 ± 0.4% MJ/Nm 3 at optimal process conditions with an average yield of 2.20 ± 0.001 m 3 /kg. Based on the solid residue and thermal conversion efficiencies, 82.67 ± 1.2% of biomass was converted to syngas and 66.70 ± 2% of biomass energy was extracted through gasification. This research provides a firm and novel foundation for a long term, efficient and cost-effective hybrid gasification system capable of handling a wide range of high-volume biowaste feedstock, particularly cattle dung. Graphical abstract