Linear pyrolysis of cellulosic and plastic waste

Numerical simulations of the linear pyrolysis of cellulose and polyethylene are presented. Depolymerization and melting are followed, in the first case, by a competition between the formation of tar vapors and char (with some gas), and in the second case, by complete devolatilization. Surface regression, property variation, heat convection and conduction through the virgin solid and the molten layer are properly taken into account. The dependence of process dynamics, regression rate, surface temperature and thickness of the reaction zone on the heating conditions is simulated. The results are important in order to clarify the role of internal and external heat transfer mechanisms and the differences between the two fuels, with a view of energy recovery through MSW pyrolysis. (C) 1997 Elsevier Science B.V.