Volatiles Release Rates and Temperatures during Large Particle Refuse Derived Fuel—Municipal Solid Waste Devolatilization

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Abstract
Practices to minimize pollutants from municipal solid waste combustion devices include preparation steps to provide relatively uniform feed particles. This is the rationale behind commercially available densified refuse-derived fuel (d-RDF). However the solid phase devolatilization rate, the composition and rate of production of reaction products and pollutants, and the influence of waste feed properties on these processes have not been quantified. Devolatilization experiments were performed on single, well-characterized d-RDF particles under carefully controlled conditions of practical importance. Intrapar-ticle temperature histories, gas evolution rates and compositions were measured. The results presented here quantify the simultaneous effects of both initial moisture and particle heating rate on the intraparticle temperature field which controls the extent of local reaction. It appears moisture does not strongly alter the overall production of both gases and condensibles (tars) from the devolatilization, as long as the particle is heated with sufficient intensity (at least 5cal/cm3 at the surface) for a sufficient length of time, and as long as the plastics content is not high. When the initial moisture levels of MSW exceed 15% (dry basis) the rate of volatiles release is delayed. Increased plastics content of the d-RDF increases the fractional condensibles yield at the expense of gas yield, and causes a slight increase in the hydrocarbon content of the gas.