High temperature oxidation of C2Cl4/CH4 mixtures

Area of Science:

• Chemical Engineering
• Combustion Science
• Environmental Chemistry

Background:

• Multi-chlorinated hydrocarbons like tetrachloroethylene (C2Cl4) pose environmental concerns.
• Understanding their high-temperature oxidation is crucial for developing effective disposal and remediation strategies.

Purpose of the Study:

• To investigate the high-temperature oxidation kinetics and product formation of tetrachloroethylene (C2Cl4) when reacted with methane (CH4).
• To determine the influence of equivalence ratio and oxygen concentration on the decomposition pathways and product yields.

Main Methods:

• Experiments were conducted in a tubular flow reactor (15 mm i.d.) at temperatures ranging from 700 to 850°C.
• Average residence times varied from 0.3 to 1.5 seconds.
• Three equivalence ratios (fuel-lean, stoichiometric, fuel-rich) were examined to study C2Cl4 oxidation under different conditions.

Main Results:

• Global Arrhenius equations for C2Cl4 decomposition were established for lean, stoichiometric, and rich conditions.
• Key decomposition reactions, including radical chain reactions, were identified.
• Major products identified include trichloroethylene (C2HCl3), dichloroethylene (C2Cl2), carbon monoxide (CO), carbon dioxide (CO2), and hydrogen chloride (HCl).
• Minor intermediates such as vinylidene chloride (C2H2Cl2) and benzene (C6H6) were also detected.
• Increased oxygen concentration led to a decrease in the temperature required for product detection.

Conclusions:

• The study provides fundamental kinetic data for the high-temperature oxidation of C2Cl4 in the presence of CH4.
• Reaction pathways and product distributions are dependent on the fuel-air equivalence ratio.
• Oxygen availability significantly impacts the efficiency and temperature requirements for C2Cl4 destruction.