Conifer Systems - Regenerative Thermal Oxidizer

Thermal Oxidation is the most common method of Volatile Organic Compound (VOC) removal. In this process, the exhaust stream temperature is raised to a point where the bonds are broken.  The VOCs in the process exhaust stream are converted to carbon dioxide, water vapor, and thermal energy. Oxygen deficient process streams may require dilution with additional air to ensure enough oxygen is present for complete combustion.

In regenerative thermal oxidation, two heat recovery canisters containing ceramic heat recovery media operate under a “swing bed” absorption principle. The media acts as a heat exchanger for the system. This transfers a flowing fluid through the medium in the two beds using flow reversal. The process is called regeneration.

As the dirty process exhaust stream travels through the first bed of ceramic media it adsorbs heat energy stored in the ceramic media which pre-heats the exhaust stream. The exhaust stream then enters the combustion chamber and additional heat energy is added from the burner to reach the required system operating temperature. After the temperature has been elevated and retained, the now clean exhaust stream passes through the second heat recovery canister. The cold ceramic media mass then absorbs the heat energy of the exhaust stream and stores it for the reverse flow of the system. Once the heat energy of the first canister has been depleted, the flow through the system is rotated, so that the incoming cold, dirty air is directed through the second energy recovery canister, with the hot, clean air now exiting through the first recovery canister.

In a unit with three canisters the same principle applies but three different cycles are available. To prevent untreated VOCs from being out of the system during the cycle switch, the canister not part of a regeneration cycle is getting purged with air. This allows for a greater achievable destruction efficiency for the system.

By using the reversal of exhaust flow through the ceramic beds, minimal axillary heat energy is needed for the incoming exhaust to maintain the minimum operating temperature. The sizing of the ceramic media beds allows for 95% mass corrected heat recovery efficiency.