(288b) Production of Biochar and Combustible Gas from Co-Pyrolysis of Agricultural Plastic Wastes and Animal Manures

Researchers report that manure-derived biochar, the solid product obtained from pyrolyzing animal manures, has considerable potential both to improve soil quality and reduce water pollution.  One of obstacles in obtaining manure biochar is the high energy requirement of the pyrolyzing wet animal manures.  The combustible gas produced from manure pyrolysis generally does not provide enough energy to sustain the pyrolysis process.  Supplementing this process may be achieved with spent agricultural plastic films; these feedstocks have large amounts of available energy. Plastic films are often used in soil fumigation.  They are usually disposed in landfills, which is wasteful, expensive, and environmentally unsustainable.  The objective of this work was to investigate both the energetics of co-pyrolyzing swine solids with spent plastic mulch films and the characteristics of its gas, liquid, and solid byproducts.    Based on laboratory-scale pyrolysis experiments, the heating value of the product gas from co-pyrolysis was found to be much higher than that of natural gas; furthermore, the gas had no detectable toxic fumigants.  Energetically sustaining pyrolysis of the swine solids through the energy of the product gas could be achieved by co-pyrolyzing dewatered swine solids with just 10% spent plastic mulch.  If more than 10% plastic mulch is used, the co-pyrolysis would generate surplus energy which could be used for power generation.  Biochars produced from co-pyrolyzing plastic mulch and swine solid were similar to that from pyrolyzing swine solid alone based on their surface areas and ¹H NMR spectra.  The results of this study demonstrated the potential of using pyrolysis technology to manage two prominent agricultural waste streams (plastic mulch wastes and swine solids) while producing value-added biochar and a power source that could be used for local farm operations.  Pilot-scale experiments are being conducted currently and the highlights will be presented at the meeting.