Zeolite Rotor Concentration and Catalytic Combustion System

Pre-processing

To maintain long-term performance of the zeolite rotor, the particulate concentration in the exhaust gas must be controlled below 1 mg/m³. A dry-filtration unit is typically installed upstream of the system.

The dry filter consists of three stages: a primary bag filter, a secondary medium-efficiency bag filter, and a third-stage medium-efficiency bag filter.

Zeolite Wheel Concentration Treatment Stage

For low-concentration VOC exhaust, the zeolite rotor concentrates large-volume, low-concentration gas into a smaller volume of high-concentration gas, reducing the investment and operating costs of the downstream catalytic oxidation system.

The exhaust gas passes through the zeolite rotor, where VOCs are adsorbed by the zeolite material. Clean air is discharged to the atmosphere through the main fan after meeting emission standards. The vertical zeolite rotor provides a large contact area and achieves over 95% VOC removal efficiency while continuously rotating at 3–4 revolutions per hour.

When the adsorption zone becomes saturated, the rotor enters the desorption zone, where hot air at approximately 200°C from the heat exchanger releases the concentrated VOCs. After desorption, the rotor passes through the cooling zone, where fresh exhaust air cools it back to normal temperature and restores its adsorption capacity before returning to the adsorption zone.

Catalytic Combustion Treatment Stage

After desorption, the low-volume, high-concentration VOC gas first passes through a heat exchanger to recover waste heat. It is then further heated by electric heaters to reach the ignition temperature required for catalytic oxidation.

The heated VOC gas enters the catalytic oxidation bed, where VOCs are decomposed into CO₂ and H₂O under the action of the catalyst. The released heat further increases gas temperature, and the purified exhaust passes through two-stage heat exchangers for additional heat recovery.

The electric-heating system provides clean and reliable preheating. Multiple heating modules are automatically controlled by PLC with temperature interlocking. The heaters switch on or off automatically according to the exhaust temperature to optimize energy consumption and ensure safe operation. When the VOC concentration in the desorption gas reaches approximately 4,000 mg/m³, the system can achieve thermal self-balance, eliminating the need for electric heating and further reducing energy consumption.