Experimental study on CCl4/CH4/O2/N2 oxidation

Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and find incineration process optimization methods for pollution control. The reaction temperature varies from 700°C to 1000°C and the CCl4/CH4 (or Cl/H) mole ratio of the inlet mixture varies from 0.21 to 0.84. Products profiles are measured with FT-IR. It is shown that at the same initial CCl4 concentration and reaction temperature adding CH4 favors CCl4 destruction and CO2 formation. But the destruction and removal efficiency (DRE) of CH4 decreases with lower Cl/H and higher concentrations of toxic products of incomplete combustion such as COCl2 and CH3Cl are formed at the same time. The chlorine in the system favors CH4 decomposition, but it also inhibits further oxidation of CO. Higher temperature assists in both CCl4 destruction and CH4 conversion, and the concentration of toxic combustion intermediates is reduced. Increasing the temperature is the most effective way to enhance CCl4 oxidation. The CO2 concentration increases with temperature. A CO concentration peak is observed around 800°C: with a certain Cl/H, the CO concentration first increases with temperature and then declines. The effect of increasing CH4 concentration on CCl4 destruction becomes mild above 900°C. Rather, it enhances the interaction between chlorine and carbonaceous radicals, which leads to higher concentration of toxic products.

[1]  S. Senkan,et al.  Chemical structures of fuel-rich and fuel-lean flames of CCl4/CH4 mixtures , 1993 .

[2]  J. Bozzelli,et al.  Kinetic Study on Pyrolysis and Oxidation of CH3Cl in Ar/H2/O2 Mixtures , 1992 .

[3]  S. C. Saxena,et al.  Management and combustion of hazardous wastes , 1996 .

[4]  R. Barat,et al.  Thermal reactions of CH2Cl2 in H2/O2 mixtures: Implications for chlorine inhibition of CO conversion to CO2 , 1992 .

[5]  C. Koshland,et al.  Numerical simulation of the thermal destruction of some chlorinated C1 and C2 hydrocarbons. , 1992, Journal of the Air & Waste Management Association.

[6]  D. Chang,et al.  Observations of Chlorinated Hydrocarbon Droplet Gasification , 1992 .

[7]  Yang Wang,et al.  Influence of HCl on CO and NO emissions in combustion , 2009 .

[8]  D. Bose,et al.  On the Combustion of Chlorinated Hydrocarbons I. Trichloroethylene , 1983 .

[9]  L. A. Sgro,et al.  Postflame reaction chemistry of dichloromethane: variations in equivalence ratio and temperature , 2000 .

[10]  B. Dellinger,et al.  Thermal degradation characteristics of chloromethane mixtures , 1988 .

[11]  Y. Wu,et al.  The oxidation of trichloroethene with methane: experiment and kinetic modeling , 2004 .

[12]  D. Benn,et al.  Kinetics of the NO−NH3−O2 reaction , 1979 .

[13]  J. Lou,et al.  Thermal oxidation of chloroform , 1997 .

[14]  R. Lyon.  The NH3-NO-O2 reaction , 1976 .

[15]  R. Yetter,et al.  Detailed Kinetic Modeling of Moist CO Oxidation Inhibited by Trace Quantities of HCl , 1992 .

[16]  J. C. Leylegian,et al.  Laminar flame speeds and oxidation kinetics of tetrachloromethane , 1998 .

[17]  J. S. Morse,et al.  Profiles of Laminar Carbon Tetrachloride/Methane/Air Flames , 1989 .

[18]  E T Oppelt,et al.  Incineration of hazardous waste. A critical review. , 1987, JAPCA.

[19]  A. Gupta.  COMBUSTION OF CHLORINATED HYDROCARBONS , 1986 .

[20]  B. Dellinger,et al.  Oxidative pyrolysis of CH2Cl2, CHCl3, and CCl4-I: Incineration implications , 1991 .