Derived from the biodrying of municipal organic wastes (MOWs), biodried products (BPs) are widely identified as renewable energy sources. In this study, for efficient energy recovery, the pyrolysis characteristics of BPs were investigated by comprehensive kinetic analysis, with special focus on the synergistic effect of bulking agents and the influence of biodegradation. Compared with theoretical raw materials (RMs), it was suggested that the synergistic effect of organics and lignocelluloses in RMs promoted decomposition in Stage 1 (400-570 K), especially for the pyrolysis of RM using sawdust, during which the positive effect achieved decomposition in advance with lower overlap ratio (0.9264) and ΔW (-9.50% at 619.0 K) values. Furthermore, compared with RMs, it was indicated that the kinetic indices (Ea and ln A values) of the BPs were upward in Stage 1 and decreased in Stage 2 due to biodegradation. The results of ΔH, ΔG and ΔS indicated that BP pyrolysis required more heat supply as the reaction progressed but formed a more organized activated complex. In addition, biodegradation observably decreased the generation of gas products and typical functional groups of volatiles during BP pyrolysis, such as CO2 and CO, which presented decreasing ratios of 32.18-42.47% and 30.25-46.47%, respectively. In general, the pyrolysis of BPs was intensified by bulking agents and modified by biodegradation.
Keywords: Biodegradation; Biodried product; Bulking agent; Kinetic analysis; Pyrolysis.
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