NSF Award
9002844
Catalytically stabilized thermal (CST) incineration of chlorinated hydrocarbons uses catalytic surface reactions to stabilize gas phase reactions. Hot wall effects and surface- generated reactive intermediates are hypothesized to improve stabilization of gas phase chlorinated hydrocarbon combustion, enabling rapid plug flow (low residence time and small combustor size) incineration with high destruction of toxic organic species, and stable combustion of even very low BTU mixtures. Work to date has shown that a CST incinerator can stabilize methyl chloride and methylene chloride combustion sufficiently to enable high throughput plug flow operation, achieving 99.999% + destruction levels with a residence time of 15 ms. In Phase I, reaction mechanisms for methyl chloride destruction in plug flow thermally stabilized and catalytically stabilized reactors were investigated, through preliminary model development and through experimental flow tube kinetic studies. This work identified preliminary parameters and provided a initial basis for further experimental studies and development of a catalytic plug flow reactor model in Phase II, for use in Phase III prototype development and system design. First approximation plug flow thermal reactor model results predicted high destruction levels at moderately high temperature, and this was confirmed experimentally in a non-catalytic isothermal reactor. Catalytic isothermal reactor experiments altered the gas phase reaction mechanisms and significantly lowered required temperature and residence time for high destruction. The experimental findings advance fundamental understanding of the underlying mechanisms affecting chlorinated hydrocarbon combustion and emissions. Ultra-high destruction effectiveness, increased safety, small incinerator size and reduced costs will make this technology attractive to the large and growing thermal incineration market.
