Principles and Prevention of RTO Equipment Corrosion

In industrial production, Regenerative Thermal Oxidation (RTO) is astandard Waste Gas Treatment Technology. However, during operation, RTO equipment can be affected by corrosion due to the presence of corrosive elements such as chlorine and sulfur in the waste gas. Corrosion not only impacts the performance of RTO equipment but can also cause secondary pollution to the environment. This article delves into the causes, effects, and preventive measures for RTO corrosion.

I. Causes of RTO Corrosion

The corrosion of RTO equipment primarily stems from its working principle and the composition of the processed gas. In an RTO system, organic waste gas undergoes high-temperature oxidation, converting organic compounds into carbon dioxide and water. During this process, sulfur- and chlorine-containing substances, such as sulfurous or chlorinated organics, are oxidized and produce HCl and SO₂. In low-temperature zones below the acid dew point, these acidic gases react chemically with metal components, leading to corrosion.

II. Effects of RTO Corrosion

RTO corrosion not only shortens the equipment's service life but also disrupts regular system operation. Severe corrosion can result in perforations, leaks, and even safety incidents. Additionally, corrosion increases maintenance and replacement costs, imposing significant financial losses on enterprises.

II. Preventive Measures for RTO Corrosion

To effectively mitigate corrosion in RTO equipment, a series of measures can be implemented.

1. Corrosion-Resistant Materials

1.1 Selection of Suitable Corrosion-Resistant Materials

Based on the RTO system's operating environment and gas composition, materials with excellent corrosion resistance should be selected. For example:

• When sulfurous organic concentrations are low, SUS304 can be used for low-temperature zones.
• When chlorinated organic concentrations are high, duplex stainless steel 2507, Hastelloy C276, or titanium alloys are required.

1.2 Manufacturing Process Control

For low-temperature flow zones in RTO systems, strict quality control during manufacturing is essential.

• Welding should use electrodes of the same material as the base metal.
• For thicker plates, multi-pass welding with bevel cuts should be applied to ensure weld integrity and thickness.
• The material thickness should include a corrosion allowance while meeting structural strength requirements.

1.3 Regular Maintenance and Inspection

Even corrosion-resistant materials require periodic maintenance and inspection. Areas showing rust or weld defects should be promptly repaired. Additionally, comprehensive inspections should be conducted to monitor potential corrosion zones and take corrective actions.

1.4 Integration with Other Anti-Corrosion Measures

Corrosion-resistant materials alone are not foolproof. They should be combined with other measures, such as protective coatings, maintaining clean and dry equipment, controlling exhaust gas composition, and increasing inlet temperatures, for comprehensive corrosion prevention.

2. Anti-Corrosion Coatings

2.1 Selection of Suitable Coating Materials

Depending on the RTO system's working conditions, high-temperature anti-corrosion coatings should be selected to resist corrosive media effectively.

2.2 Coating Process Control

Professional coating techniques (e.g., spraying and brushing) should ensure uniform application without pores or bubbles. The coating thickness must meet anti-corrosion requirements.

2.3 Regular Maintenance and Inspection

Coatings should be inspected and maintained regularly. Damaged or peeling coatings must be repaired promptly to maintain protection.

2.4 Integration with Other Measures

Coatings should be supplemented with corrosion-resistant materials, gas composition control, and other preventive strategies.

2.5 Continuous R&D and Innovation

Enterprises should stay updated on advanced coating technologies to enhance the durability of their RTO systems.

3. Increasing RTO Inlet/Outlet Temperatures

3.1 Setting Appropriate Temperatures

Based on the RTO system's environment, gas composition, ceramic bed height, and valve type, inlet and outlet temperatures should be optimized. For example:

• Since HCl's dew point at normal conditions is ~108.65°C, the outlet temperature should be maintained above 110°C.

3.2 Control and Operating Systems

Preheating systems must ensure stable and accurate temperature control while being easy to maintain.

3.3 Regular Maintenance and Inspection

Temperature-dependent processes are influenced by exhaust parameters and equipment conditions, necessitating periodic checks and adjustments.

IV. Latest Anti-Corrosion Technologies for RTO

Xi'an Yurcent Environmental Technology Co., Ltd., a high-tech enterprise specializing in VOC waste treatment and carbon emission reduction, has developed a "Heavy-Duty Anti-Corrosion RTO" by leveraging aerospace-grade anti-corrosion technology. This innovation effectively resolves RTO corrosion issues, ensuring 3-5 years of corrosion-free operation regardless of chlorine or sulfur content.

Conclusion

RTO corrosion is a critical issue that affects equipment performance and imposes financial burdens. Implementing preventive measures—such as corrosion-resistant materials, protective coatings, and temperature control—can significantly reduce corrosion risks. Regular monitoring and maintenance are essential to ensure long-term system stability. Enterprises must proactively address corrosion to safeguard sustainable operations.