Anti-corrosion coatings commonly used in regenerative thermal oxidizer (RTO) systems

Corrosion of the regenerative thermal oxidation (RTO) system used in the pharmaceutical and chemical industry is a common phenomenon in the application of RTO, especially in the VOCs emitted by the fine chemical industry, which may contain halogen elements, inorganic acids, organic acids, and other components, which have a strong corrosive effect on metal materials. These corrosion problems not only have a negative impact on the system performance but also reduce the service life of RTO.

The corrosion conditions that may occur during the operation of RTO can be divided into chemical corrosion and electrochemical corrosion. Chemical corrosion refers to the corrosion caused by the chemical reaction between the metal surface and the surrounding medium, while electrochemical corrosion is caused by the electrochemical reaction between the metal and the electrolyte. In addition, since the operation temperature of RTO exceeds 760 ℃, there may also be a certain degree of contact between the metal material and the high-temperature area due to different processes in the RTO, which may also cause high-temperature gas corrosion. In view of these corrosion conditions, how to prevent corrosion and how to select anticorrosive coatings in the design of RTO are crucial for extending the service life of RTO.

The anti-corrosive coatings commonly used in regenerative thermal oxidation (RTO) systems mainly include the following types:

1、Epoxy zinc phosphate paint, epoxy zinc-rich paint, inorganic zinc-rich paint: these paints are suitable for a temperature range of 60°C to 120°C and have good corrosion resistance.

2、Epoxy resin coating, epoxy amine coating, epoxy phenolic resin coating, polyurethane coating, polysiloxane coating: These coatings are suitable for the temperature range of 120°C~150°C and can effectively resist high-temperature corrosion.

3、Organosilicone coatings, inorganic copolymer coatings: suitable for a temperature range of 150°C to 400°C, providing corrosion protection at high temperatures.

4、Inert inorganic copolymer coating: For temperatures exceeding 400°C, this coating is usually selected, which uses inorganic polymer as the main interpenetrating network polymer as the film former, and has good temperature resistance, film formation and adhesion.

The selection of these paints needs to be determined according to the specific working conditions and temperature requirements of the RTO device. The following are some commonly used paints that can play a very good protective role in the corrosion prevention of the RTO.

ZS-1034 Acid and alkali resistant anticorrosive coating, ZS-711 Inorganic anticorrosive coating, ZS-811 High temperature resistant anticorrosive coating, ZS-821 Ceramic anticorrosive coating.

ZS-822 Composite Ceramic High Temperature Anti-corrosion Coating: This coating uses fluorosilicone modified resin as the film former, and adds rare earth micro-powder, composite α-ceramic micro-powder, silicon carbide, etc. as the coating filler. The coating can withstand a temperature of up to 1400 ℃, has high adhesion and hardness, high impact strength, and can withstand acid and alkali corrosion for a long time.

ZS-1041 Flue Gas Anticorrosive Coating: This coating is made by modifying inorganic silicate resin with organic polymers, which forms a film solution with low surface energy, high corrosion resistance, high hardness, and strong adhesion to the substrate. It is suitable for anti-corrosion of high-temperature flue gas.