Co-Pyrolysis of Spent Plastic Mulch with Animal Manures.

Pyrolyzing various livestock and agricultural wastes produces power and value-added byproducts.  It also substantially reduces ultimate waste volume to be disposed of and improves soil fertility and promotes carbon sequestration via soil application of biochar. Researchers found that manure-derived biochars containing high levels of nutrients can upgrade soil quality and remove contaminants in water and soil. However, the combustible gas produced from manure pyroysis does not provide enough energy to sustain the process. Spent agricultural plastics are usually disposed in landfills, which is not only expensive, but also not environmentally sustainable as the space for landfill is increasingly limited in the U.S.  Pyrolysis of spent agricultural plastic produces high energy combustible gas, oil and wax. Thus, co-pyrolyzing animal manures with plastic may achieve an energetically sustainable pyrolysis process. The objective of this work was to investigate the feasibility of co-pyrolyzing spent agricultural plastic mulches and animal manures. Dried swine manure and spent fumigation plastic mulch were used as a hybrid feedstock for a batch pyrolysis reactor system. The reactor sample was heated to 500 °C at an approximate heating rate of 7 °C/min and stayed at 500 ^oC for 2 hrs before cooled down to room temperature.  Gaseous, liquid, and solid end products were analyzed for their chemical and thermal properties. Preliminary results indicated that pyrolysis of spent fumigant plastic alone produced fumigant-free combustible gases, liquid oil, and paraffin-like waxes.  Results from thermogravimeteric analyses and chemical characteristics of end products will be presented at the meeting.