RTO-Regenerative Thermal Oxidiser
With this method, autothermal operation (operation without the need for additional primary energy), is possible with solvent concentrations as low as 1.2 g/m³. The RTO is still very cost effective at lower concentrations because the internal heat recovery is so high, up to 98%.
The solvents contained in the exhaust air are oxidised to produce carbon dioxide and water vapour in a combustion chamber at temperatures from approximately 800 to 830°C. The internal heat recovery is achieved in this case by using the highly effective ceramic heat exchanger system, XtraComb ®, developed by KBA. This is flushed through alternately with clean gas and raw gas so as to absorb as much of the heat energy from the hot clean gas and transfer the energy to the cold raw gas.
The regenerative method is an intermittent process, were the exhaust air flow is switched over cyclically, providing a energy transfer between the hot clean gas and the cold raw gas.
KBA CleanAir systems are designed to minimize operating costs. They are always customer optimized e.g. using special control systems according to the operating conditions in each case, in order to maximise efficiencies and minimise operating costs.
Various series are available with this method depending on the application:
- Small systems: RTOcompact
The most well-known regenerative system is the 3-canister system where the exhaust air being cleaned is switched over cyclically between three canisters (raw and clean gas or purge canister). This method meets the highest standards and guarantees minimum clean gas values.
Residual volumes of exhaust air still in the raw gas canister at the time of switching over are first purged out of the third canister before the canister can be used as a clean gas canister during the next cycle. This reliably prevents emission peaks arising in the clean gas and makes sure that the required limits are not exceeded, even with solvent concentrations up to 12 g/m³ in the exhaust air.
Examples of additional devices
- Hot bypass for energy removal at very high concentrations
- On-line or off-line Burnout for cleaning the ceramic heat exchanger
- Innovative energy management systems XtraBalance and XtraControl
- Waste heat boiler for steam, heat-transfer oil or hot water
With the 2-canister series, the third canister, "purge canister", is not present. However, rapid, airtight KBA-valves in a durable industrial design, secure the lowest clean gas values even when using this mode of operation.
By including a buffer system, the switchover peaks can be captured and unburned hydrocarbons fed back into the installation.