Volatile Organic Compound (VOC) Recovery

• VOC stands for Volatile Organic Compounds. VOC emissions consist of a mixture of hydrocarbons and non-hydrocarbons with varying molecular sizes and chemical structures. Controlling VOC emissions is necessary across various industries, including petrochemical processes, emissions from oil tank vents, gas filling, solvent tanks, and exhaust in painting plants.

• Taiwan Heat Transfer offers several methods for VOC treatment:

1. Condensation: The principle of VOC recovery technology through condensation involves cooling and pressurizing the VOC vapors to condense them back into a liquid state, thus completing the recovery process. While condensation can fully recover VOC liquids, it typically consumes more energy.

2. Adsorption: Adsorption is suitable for low concentration, high-volume organic waste gases, with relatively lower energy consumption. The most common adsorbent is activated carbon, but the drawback is that the equipment size is relatively large, and the process is complex, requiring regeneration or replacement of adsorbents.

3. PSA (Pressure Swing Adsorption): PSA separation and purification technology utilize the adsorption characteristics of gas components on solid materials, primarily using zeolite molecular sieves. Zeolite molecular sieves can adsorb organic components from organic waste gases, and then the remaining gas is sent to the next process, while the molecular sieves can be regenerated for repeated use.

4. Catalytic Oxidation: This method involves heating the gas to temperatures of 300-400°C, causing VOC to undergo oxidation reactions with O2, producing CO2 and H2O. Catalytic oxidation can treat low-concentration VOC, and the reaction process does not produce flames.

5. Photocatalytic Oxidation: This method utilizes the catalytic properties of TiO2 under irradiation from an exciting light source to absorb light quantum by pollutant molecules, thus destroying the pollutant molecules. It is suitable for low-concentration waste gases with strong light quantum absorption.