Naval painting VOC emissions control systems

The application of paints on ferrous materials takes place in closed, large rooms, using solvent-based products, which are released into the work environment and extracted from special ventilation systems both during the application phase and during the subsequent one of drying or withering; emissions into the atmosphere therefore contain Volatile Organic Compounds (V.O.C.) and dust generated by the paint fractions (overspray) that failed to settle on the part to be painted and which can be emitted into the surrounding environment generating olfactory nuisance and environmental pollution.

Without dedicated treatment technologies, these pollutants may significantly impact air quality and environmental compliance.

According to the European Environment Agency, VOC emissions are among the main contributors to industrial air pollution and ozone formation.

Atmospheric emissions deriving from naval painting processes have the following characteristics:

The purpose of purification is mainly to minimize the emission into the atmosphere of those pollutants harmful for the environment (VOC), in compliance with the regulatory limits set for each pollutant individually, minimizing the formation of secondary pollutants and with costs investment and management acceptable for the production process.

Reducing naval painting VOC emissions is essential for ensuring environmental compliance and improving air quality in shipyard operations.

To solve the environmental issue characterized by extremely high airflow rates and relatively low pollutant concentrations, Brofind® combined two complementary technologies.

The first stage consists of a rotor concentrator system, which transfers pollutants from a very large airflow into a smaller concentrated stream. This process significantly reduces the air volume requiring final treatment while increasing VOC concentration.

The pollutant transfer occurs through a special adsorbent material capable of retaining VOCs and releasing them during the regeneration phase through controlled heating.

The concentrated emission is then treated by regenerative thermal oxidation (RTO), a technology particularly effective for VOC destruction.

Regenerative thermal oxidation converts organic pollutants into compounds with lower environmental impact, mainly water vapor and carbon dioxide. Since oxidation reactions require temperatures between 800°C and 900°C, the system integrates high-efficiency ceramic heat recovery media capable of minimizing auxiliary fuel consumption.

Rotoconcentration is a process frequently used for the treatment of atmospheric emissions containing vocs released in industrial painting processes, characterized by the need to treat high air flows and reduced quantities of pollutants; it is not a final treatment, for which it must be combined with another technology: in this case, it has been combined with regenerative thermal oxidation, which completes the purification of the concentrated emission.

The application in the naval industry had to foresee the identification and application of specific measures aimed at enabling the following goals:

• The achievement of the highest purification performances, through a specific sizing of the process parameters.
• The optimization of energy consumption, thanks to the combination of multiple technologies, aimed at allowing the treatment of high air flow rates with reduced quantities of pollutants.
• The ability to resist any dirtying and clogging phenomena caused by the presence, in the emission, of organic dusts resulting from the overspray produced in the painting process.
• Plant durability over time, through the use of resistant materials and components in the presence of marine environments.