Mechanism and Solutions for Dew Point Corrosion in RTO

Organic chlorine elements in exhaust gases combust within the Regenerative Thermal Oxidizer (RTO) system to form hydrogen chloride (HCl) and water vapor (H₂O). When the temperature in the lower, cooler regions of the RTO unit falls below the acid dew point temperature of hydrogen chloride, HCl condenses on the surfaces of materials in these cooler zones. This condensation, combined with water generated from reactions brought in by the exhaust, forms hydrochloric acid solutions that corrode metal surfaces.

Additionally, the sulfur content in fuels significantly influences dew point corrosion. Higher sulfur content leads to increased production of SO₂ and SO₃, raising the dew point temperature. When the metal wall temperatures in the cooler regions of the RTO drop below this dew point, water vapor condenses on the metal surfaces, combining with SO₃ to form sulfuric acid vapor. This vapor condenses into acidic liquid in the cooler regions, further corroding the metal surfaces.

Moreover, the oxygen content in the tail gas also affects dew point corrosion. Excess oxygen is essential for the oxidation of SO₂ to SO₃. A higher air excess coefficient means more excess oxygen and consequently more SO₃. As the air excess coefficient decreases, the concentration of SO₃ in the flue gas significantly reduces, approaching or falling below dangerous corrosion levels, and the dew point temperature also drops. When the air excess coefficient is less than 1.1 (oxygen content less than 2%), the dew point temperature decreases sharply.

1. Reducing or Preventing Dew Point Corrosion in RTO Organic Exhaust Gases

1.1. Pre-treatment

Before entering the RTO system, exhaust gases should be pre-treated to remove inorganic substances, water-soluble materials, and moisture, thereby reducing the formation of corrosive substances.

1.2. Use of Corrosion-Resistant Materials

Critical components in the low-temperature flow areas of the RTO system should be made from corrosion-resistant materials such as stainless steel or aerospace-grade anti-corrosion materials to enhance the system's resistance to corrosion.

1.3. Control of Exhaust Gas Temperature

Properly manage the outlet temperature of the RTO system to avoid excessively high or low temperatures, which can reduce the condensation of corrosive substances.

1.4. Regular Maintenance and Cleaning

Regular maintenance and cleaning of the RTO system are performed to remove accumulated corrosive materials and maintain optimal operational conditions.

1.5. Enhanced Monitoring

Regularly monitor the RTO system for signs of corrosion to identify and address any issues promptly.

1.6. Protective Coatings

Apply anti-corrosion coatings such as protective paints, anti-corrosion layers, graphene coatings, or carbon fiber coatings to metal surfaces to enhance their corrosion resistance.

1.7. Control of Chlorine Content in Raw Materials

Minimize the chlorine content in organic exhaust gases to reduce the generation of corrosive substances like hydrogen chloride.

Implementing these measures can effectively prevent dew point corrosion in RTO systems handling chlorine- and sulfur-containing organic exhaust gases, extending equipment lifespan and ensuring stable system operation.

 2. Features of Heavy-Duty Anti-Corrosion RTO

Heavy-duty anti-corrosion RTO is specifically designed for treating chlorine-containing organic exhaust gases. It incorporates advanced anti-corrosion technologies and materials to effectively prevent corrosion issues during the processing of such gases.

2.1. Use of Corrosion-Resistant Materials

The low-temperature zones of the RTO are constructed with aerospace-grade anti-corrosion materials, enhancing the equipment's resistance to corrosion.

2.2. Advanced Anti-Corrosion Coating Technology

Surfaces are coated with graphene and carbon fiber layers, significantly boosting the equipment's anti-corrosion capabilities.

2.3. Efficient Anti-Corrosion Structural Design

Special structural designs and anti-corrosion linings in the low-temperature zones of the RTO reduce the likelihood of corrosion.

2.4. Improved Operational Stability and Reliability

Optimized control mechanisms lower operational energy consumption and costs while reducing the potential for equipment failures.

In summary, heavy-duty anti-corrosion RTO represents an efficient and reliable solution for treating chlorine-containing organic exhaust gases, with broad application prospects.