Common Vapor Treatment Technologies

Catalytic Oxidation

Catalytic Oxidizers use temperatures that are lower than non-catalytic thermal oxidizers and a solid catalyst (a compound that speeds chemical reaction rate) to react pollutants in air streams. VOCs are thermally destroyed at temperatures of 600 (315 ^oC) to 1,000 °F (540 ^oC), using a solid catalyst. First, the contaminated air is directly preheated (electrically or, more frequently, using natural gas or propane) to reach a temperature necessary to initiate the catalytic oxidation of the VOCs. The preheated VOC-laden air is passed through a bed of solid catalysts where the VOCs are rapidly oxidized. In common with thermal oxidizers, oxidation of halogenated VOCs produces acid vapor. Off-gas scrubbing may be needed to control the acid vapor. Figure 1, below, shows a diagram of this system.

Figure 1: Schematic of Catalytic Oxidation Process

This type of treatment is most frequently use for nonhalogenated VOCs and SVOCs, and fuel hydrocarbons. Both precious metal and base metal catalysts have been developed that are reportedly capable of effectively destroying halogenated (including chlorinated) hydrocarbons. Specific chlorinated hydrocarbons that have been treated include TCE, TCA, methylene chloride, and 1,1-DCA. (Summary adapted from the Federal Remediation Technologies Roundtable.)

For more detail regard catalytic oxidation, click on the following link to the Federal Remediation Technologies Roundtable FRTR Section 4 - Oxidation.

A technical report summary (in PDF format) involving a site in Battle Creek, Michigan utilizing catalytic oxidation or granular activated carbon to control SVE vapors may be downloaded by clicking on the following link U.S.E.P.A. Verona Field Report.