Distribution of solar pyrolysis products and product gas composition produced from agricultural residues and animal wastes at different operating parameters

Solar energy and biomass are the two major sources of renewable energy, which can be integrated to produce heat, power and transportation fuels, chemicals and biomaterials using pyrolysis. In this work, separate samples of chicken-litter waste and rice husk of different particle sizes (280 and 500 μm) were pyrolysed with a concentrated solar radiation to produce pyrolysis gases of high calorific value. Different operating parameters were investigated under the solar pyrolysis conditions. Heating rates from 10 to 500 °C/s and temperatures in the range of 800–1600 °C, generated from a lab-scale solar furnace with maximum power capacity of 1.5 kW, were applied. Temperature was found to have the highest effect, changing the gas yield from 10 to 39 wt%; decreasing the bio-oil and char yields from 48 to 41 wt % and 42 to 18 wt%, respectively as the temperature increased from 800 to 1600 °C. The highest specific energy content of the gas (7255 kJ/kg) was obtained with the 280 μm particle size chicken litter at 1600 °C. Overall, gases produced from solar assisted biomass pyrolysis have a high concentration of combustible products that could be directly used as fuels in engines or power plants.