OM-5 chimney high-temperature, acid resistant and anti-corrosion coating

After the approval of the original power industry standard DL/T901-2004 by the Ministry of Electric Power in Yixing in 2004, the corrosion of the inner lining caused by changes in flue gas humidity and temperature after chimney desulfurization has attracted high attention from all parties. Shandong Electric Power, as the drafting unit of the industry standard DL/T693-1999 for acid resistant and corrosion-resistant coatings for chimney concrete by the Ministry of Electric Power, reviewed and reflected on the technical indicators of the original standard, and deemed it necessary to improve the heat resistance indicators of Type I coatings that come into direct contact with flue gas. According to the current operational situation of power plants, Type I coatings not only have to withstand the corrosion of low temperature, high humidity, and low concentration acid solution after desulfurization, but also have to withstand the test of long-term high temperature and high concentration sulfuric acid corrosion without desulfurization. Sometimes the flue gas temperature can reach 150-170 ℃, and both situations repeatedly occur. Therefore, the original heat resistance index of 250 ℃ for 1 hour seems a bit too low.

Product Summary Metrics:

1. High temperature resistance: 250 ℃.

2. Resistant to dilute acid (sulfuric acid, nitric acid, hydrochloric acid) at a concentration of 5% and a temperature of 80 ℃: no change for 12 days; Resistant to 30% sulfuric acid: no change for 15 days at 80 ℃, no change for 30 days at room temperature.

3. Water resistance: No change after soaking at room temperature for 90 days.

4. Peel resistance: (rapid cooling and heating at 250 ℃/repeated water cooling cycles) 50 times without any change.

5. Anti aging index: no change after 500h of damp heat test.

6. Service life: 13 years.

7. Construction period: 20-30 days.

Single tube old chimney to inner lining desulfurization transformation (new chimney inner lining treatment) and acid and anti-corrosion treatment plan for the inner side of steel chimney:

（1） Renovation of old chimney lining and treatment of new single chimney lining:

1. Processing methods and procedures: sweeping and cleaning (new chimneys do not have this program), brushing OM interface agent, scraping OM putty, brushing two layers of OM-4 bottom material, and then brushing two layers of OM-5 chimney high-temperature, acid resistant and anti-corrosion coating (1-2 layers of glass fiber cloth can be added in the middle) with a total thickness of 1.5-2.0mm.

2. Construction period: 20 days (210-240M chimney).

（2） Anti corrosion treatment plan for the inner side of the steel chimney:

1. Processing method and procedure: After rust removal, brush two layers of OM-4 bottom material and two layers of OM-5 chimney high-temperature, acid resistant and anti-corrosion coating, with a total dry film thickness of 0.5-1.0mm. (The design institute selects the thickness according to the needs) 2. Construction period: 20 days (210-240M chimney).