VOCs abatement evaluation of supercritical carbon dioxide green spraying in industrial surface coating

Source reduction of volatile organic compounds （VOCs） from industrial emissions is a core task for air quality improvement during the 15th Five-Year Plan period of China. Supercritical carbon dioxide （ScCO2） spraying technology emerges as a cutting-edge VOCs abatement approach， as it not only reduces VOCs emissions but also minimizes coating consumption. However， empirical research on the enhancement of coating efficiency and VOCs emission reduction effects at the demonstration application scale remains scarce. In this study， three solvent-based coating systems widely adopted in Chinese industrial enterprises were selected， namely wooden furniture-polyurethane， wooden furniture-acrylic， and metal parts-fluorocarbon. A calculation method for ScCO2 spraying efficiency and VOCs emission reduction rate was established， and its emission reduction performance was systematically measured and analyzed. The results indicated that compared with high-pressure airless spraying， the average coating efficiency improvement rates of ScCO2 spraying at spray distances of 60 cm and 40 cm across the three demonstration scenarios were （30.62±8.75）% and （31.74±12.83）%， respectively. Correspondingly， the average VOCs emission reduction rates achieved by ScCO2 spraying under the same conditions were （62.10±1.59）% （60 cm） and （53.73±11.78）% （40 cm）. This study confirms that ScCO2 spraying can achieve significant reductions in VOCs and solvent emissions in the coating processes of wooden furniture and metal parts， providing empirical support for its industrial promotion.