Experimental study on CCl4/CH4/O2/N2 oxidation

Abstract

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.