In the context of large-scale and automated development in the coating industry, spray booth exhaust treatment has become a key aspect of air pollution control and corporate environmental compliance. Exhaust generated during spraying and drying processes features high airflow, low concentration, and complex composition. Direct discharge can have significant impacts on the environment and human health. Proper management of spray booth exhaust is not only a regulatory requirement but also an important measure to promote the green upgrading of the coating industry.

Spray booth exhaust primarily consists of three types of harmful substances: first, paint mist particles suspended in the airflow, which are fine and easily dispersed; second, water-based or oil-based paint droplets generated during spraying, containing organic solvents and resin components; third, organic exhaust from the volatilization and curing reactions of coatings, thinners, and curing agents, with core components including benzene, toluene, xylene, and other VOCs. These pollutants not only irritate the respiratory system and eyes, but long-term exposure also poses health risks, and they are key precursors to ozone and PM2.5 formation.

As environmental standards continue to tighten, single-treatment equipment cannot meet compliance requirements. The industry commonly adopts pre-treatment + deep purification integrated processes to efficiently remove paint mist and VOCs. Mainstream treatment technologies are generally categorized into three types.

Filtration + Adsorption is a widely used economical process. Exhaust first passes through equipment such as water curtains and dry filtration boxes to remove paint mist particles, preventing blockage in subsequent adsorption units. The purified gas then enters an activated carbon adsorption unit, which utilizes the high surface area of activated carbon to adsorb low-concentration VOCs. This process is suitable for spray conditions with high airflow and low concentration.

Filtration + Catalytic Combustion is a high-efficiency and stable mainstream process. After pretreatment, the exhaust enters an activated carbon adsorption unit. Saturated activated carbon is regenerated via hot air desorption, concentrating low-concentration exhaust into high-concentration exhaust, which then enters catalytic combustion equipment. Under the action of the catalyst, VOCs are oxidized at low temperatures (280–350℃) into carbon dioxide and water, achieving purification efficiency above 97%. The system can operate automatically, offering good long-term economic performance.

Water Scrubbing + Adsorption focuses on wet pretreatment. Exhaust is washed through a water curtain cabinet or swirl scrubber tower, efficiently removing paint mist and some soluble organics, followed by activated carbon adsorption to meet emission standards. This process is stable, easy to maintain, and commonly applied in small to medium spray booths and water-based paint spraying scenarios.

With increasingly stringent environmental requirements in the coating industry, spray booth exhaust treatment is moving toward high efficiency, integration, and intelligence. Combined processes, zeolite wheel concentration, and RTO regenerative thermal oxidation technologies are gradually being adopted, further improving treatment effectiveness and energy efficiency. Enterprises should select appropriate processes based on exhaust airflow, concentration, coating type, and site conditions to achieve stable compliance, safe production, and green development simultaneously.