Discussion on the corrosion repair of petrochemical concrete structure cooling towers
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We know that the corrosion-induced damage to industrial concrete structure cooling towers is caused by the following factors: 1. The acidic substances present in the industrial atmosphere react with tricalcium aluminate and calcium hydroxide, which are present in the solidified products resulting from cement hydration, to form salts that are somewhat soluble. As these corrosive substances continue to be supplied and water is lost through evaporation, it leads to the destruction of the structural components. 2. When it rains, CO2 in the air reacts with water to form H2CO3, which gets trapped in the pores of the concrete. However, H2CO3 in water can also react further with CaCO3 to produce Ca(HCO3)2, which is soluble in water; this process gradually dissolves and carries away the useful components within the concrete. The Ca(HCO3)2 that is dissolved is replaced by solid Ca2CO3, thereby damaging the concrete. 3. The circulating water has a calcium carbonate composition; when the cooling tower is in operation, some water vapor is carried away by the fans and sprayed onto the outer wall at the top of the tower. When CaCO3 in water is at saturation, there is a capacity to continue dissolving CaCO3 as well as the carbonates in concrete, resulting in a decrease in concrete strength. Below is information on surface corrosion in the cooling towers of refining systems, along with the methods that can be used to address corrosion-related damage.
To repair the corrosion of the concrete structure in petrochemical cooling towers, the following methods can be employed: 1. **Surface coating protection**: Apply acid- and alkali-resistant anti-corrosion coatings to the surface of the cooling towers, such as epoxy or polyurethane coatings; this helps to prevent corrosive substances from coming into contact with the concrete structure. 2. **Waterproofing treatment**: Apply a waterproofing treatment to the concrete surface to reduce the penetration of water and corrosive chemicals; permeable waterproofing agents such as silanes or other hydrocarbon-based polymers can be used for this purpose. 3. **Structural reinforcement**: Repair the damaged concrete by using materials with high durability and corrosion resistance, such as repair mortar and concrete additives, to restore and strengthen the structure. 4. **Regular inspection and maintenance**: Establish a regular inspection system to detect and address early signs of corrosion promptly, thereby preventing the spread of corrosion from causing more severe structural damage. By implementing these strategies, it is possible not only to repair already corroded concrete structures but also to prevent future corrosion issues, thereby extending the service life of cooling towers. .