Cogasification of typical plastics and rice straw with carbon dioxide

Abstract

Cogasification of high‐calorific‐value plastics with biomass can effectively improve the quality of gas production and utilize plastic waste as a resource. In this study, the gasification characteristics of rice straw with three types of typical plastics in a carbon dioxide (CO2) atmosphere were evaluated, and the relevant kinetic parameters were calculated using a thermogravimetric and differential thermal analyzer (TG/DTA). In the case of gasification of plastics only, the integral difference in TG (ΔM) showed that polyethylene terephthalate (PET) with poor thermoplasticity promoted the pyrolysis of rice straw, whereas polyethylene (PE) with good thermoplasticity hindered it. Furthermore, the effects were strengthened with increasing ratio of plastics/rice straw. In the case of cogasification of plastics and rice straw, the mass loss of mixture is higher than the linear sum of the parent fuels. The cogasification of plastics and rice straw had a synergistic effect; the plastic content had a greater effect on ΔM. In this study, all the maximal ΔM was more than 10%. The kinetic analysis showed that the synergistic effect of the plastics and rice straw reduced the activation energy of the gasification reaction. The minimal activation energies of rice straw with PE, poly(vinyl chloride), and PET in the cogasification were 32.52, 59.65, and 65.77 kJ/mol, respectively, all of which were less than the weighted summation of the individual activation energies of the plastics and rice straw. © 2014 American Institute of Chemical Engineers Environ Prog, 2014 34: 789–794, 2015