Postflame reaction chemistry of dichloromethane: variations in equivalence ratio and temperature

Abstract

We report on the destruction pathways and byproduct formation of dichloromethane (CH 2 Cl 2 ) in conditions typical of incinerator postflame regions (injection temperature ϭ 900 -1200 K; equivalence ratio ϭ 0.6, 0.9, 1.0, 1.1; residence time ϭ 0.28 -0.35 s). This is the first study to independently vary equivalence ratio and temperature, and evaluate their impacts on byproduct yield and destruction efficiency. We inject 750 ppm CH 2 Cl 2 into postflame combustion products and measure byproducts with extractive FTIR spectroscopy. We use a detailed chemical kinetic mechanism and reaction rate analysis to predict the changes in reaction pathways as a function of equivalence ratio. The predictions for major products and several intermediate species compare well with experiments; the largest disparities are an underprediction of phosgene (CCl 2 O) and an overprediction of methyl chloride (CH 3 Cl). Both the experiment and the numerical predictions show increased destruction at lower equivalence ratios. However, the experiments reveal increased levels of stable chlorinated organics at lower equivalence ratios, opposite to the numerical prediction. We discuss reasons for this discrepancy and implications of these results for designing control strategies to promote full conversion to HCl and to reduce chlorinated byproduct emissions.

Synthesis, Separation, and Characterization of Fullerenes and Their Chlorinated Fragments in the Glow Discharge Reaction of Chloroform

“…In the glow discharge experiment, the reactions in the two reactors were carried out under the same vacuum and sharing the same electrical power source but were fed different starting reactants. In reactor I, the reactant was chloroform vapor, while the reactants in reactor II were composed of variety of volatile chlorinated carbon species formed in the preceding reactor, such as C 4 or C 6 . The experimental evidence suggested the possibility of designing the proper precursors so as to improve fullerene yield in the synthetic reaction.…”

Experimental study on CCl4/CH4/O2/N2 oxidation

“…Incineration is an attractive technology due to volume reduction, detoxification of wastes and heat and materials recovery [3][4][5]. Previous studies have shown that chlorinated hydrocarbons flames have lower flame velocities and that toxic products of incomplete combustion are formed [4,[6][7][8][9][10][11][12]. To use this technology safely, it is important to understand the combustion characteristics of chlorinated hydrocarbons and the influence of chlorinated hydrocarbons on the combustion chemistry of hydrocarbons.…”

Reaction of dichloromethane under non-oxidative conditions in a dielectric barrier discharge reactor and characterisation of the resultant polymer

“…There are several similarities in the product distribution reported by these researchers and in the results obtained in the present study. For instance, the product distribution reported by Srgo et al included species such as C 2 HCl 3 , C 2 H 3 Cl, cis and trans C 2 H 2 Cl 2 , CHCl 3 , C 2 H 2 , C 2 H 4 and HCl [6,8] .…”

“…Prior investigations on DCM decomposition involved the study of various process parameters and reaction conditions, such as addition of hydrogen/oxygen mixtures, oxidative pyrolysis and the effect of temperature and equivalence ratio, using high temperature technologies [6][7][8]. In the plasma field, various technologies such as RF, pulsed corona and DBD have been employed to investigate DCM decomposition, using carrier gases such as nitrogen, air and argon under varying experimental conditions [9][10][11][12][13][14][15].…”