Energy & Fuels, Vol.32, No.4, 4341-4349, 2018
Waste to Energy Conversion of Chicken Litter through a Solar-Driven Pyrolysis Process
Application of solar energy for biomass pyrolysis is a promising technology for converting biomass to energy, fuels, and other chemical substances with neutral CO2 emissions. In comparison to the conventional pyrolysis process, the biomass conversion efficiency can be greatly improved if the pyrolysis heat is supplied from a concentrated solar system, which can be achieved at reasonably moderate solar radiations. This paper discusses fast pyrolysis of chicken litter at different temperatures (560, 760, 860, and 900 degrees C) supplied from a solar dish of maximum flux density of 69 087 W/m(2) under 1000 W/m(2) of net (all wave) solar radiation. Yields of the different product fractions (gas, liquid bio-oil, and solid biochar) were assessed using different techniques. The gas yield increased with the temperature from 45.3 wt % at 560 degrees C to its maximum value of 58.6 wt % at 860 degrees C. Gas chromatograph results showed CO2, CO, and CH4 as the dominant gases, with contents of 30.2, 22.4, and 2.4 wt %, respectively. When the temperature increased to 900 degrees C, lower gas yields of 48 wt % were produced. The gas chromatography mass spectrometry analysis showed that the generated bio-oils (14-36 wt %) mainly contained fatty acids, phenols, sterols, and nitrogen-containing compounds. Scanning electron microscopic images of evolved biochars showed an increasing porous structure with the temperature, while Fourier transform infrared spectroscopy of the biochars showed the presence of -OH, aliphatic C-H, and other functional groups in the biochar, which gradually disappeared with the temperature. The obtained results revealed the potential use of solar energy in the waste to energy valorization of organic chicken litter waste.