The coating workshop is a key area of energy consumption and emissions in shipbuilding and is subject to stringent environmental regulations. Jiangsu Haizhongzhou Shipping Industry Co., Ltd. has systematically developed a green coating workshop system guided by the principles of “source reduction, process control, and end-of-pipe treatment,” significantly reducing environmental impact while ensuring coating quality.
For VOC abatement, the workshop employs a combined process of “zeolite rotor adsorption concentration + regenerative thermal oxidizer (RTO).” Spray exhaust air first passes through dry filters to remove paint mist particles, then enters the zeolite rotor for adsorption concentration. The rotor rotates slowly at several revolutions per minute: the adsorption zone captures VOCs, the cooling zone reduces temperature, and the desorption zone uses a small volume of hot air to release highly concentrated VOCs. The desorbed high-concentration gas enters the RTO, where it is oxidized at temperatures exceeding 800°C into carbon dioxide and water, achieving a purification efficiency of over 95%. The RTO uses honeycomb ceramic media for heat recovery, reaching a thermal efficiency of approximately 95% and significantly reducing operating energy consumption.
For paint residue reutilization, the workshop has established a strict residue recovery management system. After spraying operations, unused paint and thinners are sealed and stored by type, color, and batch, with remaining quantities recorded. Through a small-batch blending system, these residues are prioritized for use on non-cosmetic surfaces, primers, or temporary protective coatings. Overspray paint sludge generated during spraying is collected by category and entrusted to licensed hazardous waste treatment facilities for resource recovery or safe disposal.
Additionally, the workshop actively promotes waterborne coatings and high-solid coatings as replacements for traditional solvent-based products. Waterborne coatings use water as a diluent, reducing VOC content by over 70%. High-solid coatings have a volume solids content exceeding 80%, achieving design film thickness in a single coat and reducing the number of spray passes and solvent usage. Currently, VOC emissions per unit area at Haizhongzhou Shipbuilding’s coating workshop exceed China’s National Grade I Cleaner Production Standard, with annual VOC reductions exceeding 30 tons. Green coating is not only an environmental responsibility but also a manifestation of corporate competitiveness.