(37a) Solid Fuel Formation By Co-Pyrolysis of Bamboo and Simulated Waste Plastic

Co-pyrolysis of bamboo and plastic powder was conducted in order to investigate how to produce “ecological” solid fuel. The mixing percentage of the powders w_p and the setting temperature of the reactor wall T_S were changed. At T_S = 573 K the decomposition of the simulated waste plastic was progressed on the surface of the bamboo char during co-pyrolysis while the tar from bamboo pyrolysis was wrapped by the molten plastic. The pores on the surface of the bamboo particles decreased with w_p because they could be wrapped by the molten plastic. The particle size increased with w_p. On the other hand, at T_S = 673 K the co-pyrolysis of bamboo and simulated waste plastic was disturbed partly by the interaction during co-pyrolysis of Polypropylene (PS) and Polyethylene terephthalate while the co-pyrolysis of bamboo and PS was progressed. The grindability increased with T_S and decreased with w_p as most of the molten plastic coagulated after co-pyrolysis because the shape of particles changed from small fibrous particles to large granular particles with w_p. At 30 wt% < w_p < 70 wt%, the HHV at T_S = 673 K was mostly lower than that at T_S = 573 K because the char yield in the mixture was lower than that of the expected char yield due to the progress of the simulated waste plastic pyrolysis at T_S = 673 K. The energy yield had a local minimum value at w_p = 10 wt% because the char yield increased by the coating of molten plastic during co-pyrolysis even if the T_S increased. The energy yield decreased with T_S. The optimum condition for the solid fuel, which was evaluated by grindability, HHV, and energy yield was T_S = 623 K and w_p = 10 wt%.