Development of a non-equilibrium turbulent reaction model of HFC-134a in a tubular reactor

Abstract

Detailed review and discussions are made for the modeling and non-equilibrium effect in the incineration process of various halogenated hydrocarbons using a couple of modified versions of eddy breakup (EBU) model developed from the original EBU model by Magnussen and Hjertager. Further experimental and numerical studies are made for the development of a hybrid-type EBU model in order to evaluate the non-equilibrium effect of HFC-134a reaction in a tubular reactor. For the numerical calculation using the hybrid-type EBU model, especially, the relative rate of the turbulent mixing and chemical reaction should be incorporated in a harmonic mean expression. Thus the overall reaction rate expression of HFC-134a reaction is determined by the fitting the empirical constants with experimental data obtained in the tubular reactor via trial and error method. Thereby, the empirical constants in the equation of the Arrehenius type reaction rate, that is, ω̇=-kCC2H2F4CH2OCO2=-ATBe-EaRTCC2H2F4CH2OCO2 was determined, where A=1.0, B=0.38, Ea=8.8×107J/kmol, respectively. Employing this non-equilibrium model, the calculated overall destruction rate of HFC-134a was in good agreement with the experimental data obtained for the same reactor. Further, the comparison of HFC-134a concentration profiles between the fast chemistry and non-equilibrium EBU models show a significant difference even if the calculated destruction rates of HFC-134a appear similar at the exit. In near future, numerical calculation will be made for the practical incinerator of HFC-134a in a practical incinerator using the model developed in this study.