Due to gas has increasing influence on heat exchange tube, heat exchange tube heat protection has become an important work of power plants. Heat exchange plate engineering anti-corrosion and its coating are keys to the whole process. Heat exchange tube heat transfer piece generally requires no water seepage, corrosion, desulfurization. So it will have good characteristics: such as: corrosion resistance, permeability resistance, high temperature resistance, wear resistance, anti-shedding, and so on. The materials of heat exchange tube heat exchange piece is very difficult to have such a comprehensive character, must besmear anti-corrosive coating against flue gas, increase comprehensiveness and corrosion of heat exchanger. The anti-corrosion of heat exchanger depends on acid-resistance of materials, especially acid-resistance under high temperature; Permeability mainly depends on the thickness of the corrosion protection, the density of organic and inorganic components of the density of cured substance; Anti-shedding mainly relies on the construction quality, substrate quality and the temperature resistance of anti-corrosion material itself as well as stress-tolerant change of the anti-corrosion coating, Landee pipe anti-corrosive coatings can achieve the above requirements. With the performance of anti-corrosion, waterproof, anti-drop, high temperature resistant, the coating is currently the best anti-abrasive and anti-corrosive material of heat exchange tube heat exchanger.
The anti-corrosion of heat exchanger prevents it from becoming corrosive and rusty, acid and alkali resistance and corrosion?resistance of heat exchanger can last long. In recent years, in the practice of research and development of corrosion coating on the inner wall of the heat exchange tube heat exchanger, Anticorrosive coatings research and development personnel of Landee pipe co., LTD. according to hundreds of site condition of flue gas heat exchanger, adopt new technology, in combination with high and new technology, Landee company has applied flue gas anti-corrosion coating to pipes.
The general temperature of flue gas of heat exchanger is about 70 ℃ to 500 ℃, relative humidity is 3%. The flue gas contains ash content and various corrosive elements, such as, NO2 and SO2, HCl, salt fog and so on. And even some smoke contains hydrofluoric acid corrosive gas. Also, in the process of desulfurization, it featured by the alternation of acid-base value quality. The internal heat exchanger is corroded seriously, so requirements for wall corrosion conditions of heat exchanger are demanding.
Long-term Anti-corrosion: the wall smoke anti-corrosive coatings modified with inorganic polymer is improved by organic polymer. The coating can be arranged alternately of block copolymer, forming two-dimensional mesh structure state in coating space, namely forming the labyrinth dot form. The super fine powder of rare earth oxide objects of coating forming a dense interface transition zone. Under the common action, the coating effectively prevents the acid and alkali liquor corroding. This kind of coating has excellent corrosion resistance, at the same time, with a variety of corrosion of acid and alkali resistance, resisting to H2S, chloride, sulfur dioxide in flue gas, sulphur trioxide, hydrochloric acid medium corrosion, such as high moisture. It can also prevent condensate point corrosion, stress corrosion, chemical corrosion, corrosion potential, etc., effectively protect the heat exchanger from corrosion and rust.
Strong adhesion, high coefficient of linear expansion: Landee anti-corrosive coatings using special coating film, inorganic pigments as filler. The coating compositions containing chemical bonds - hydroxyl (OH), etc., combined with metal ions form chemical bonds. Under the help of coupling agent on coatings, covalent chain combination can be formed by combining well with metal ion. The coating excellent adhesion with substrate material, achieves the first level of adhesion. The coating has high resistance to flexure and thermal expansion degeneration resistance, can stand up to the unavoidable vibration during the running of steel heat exchange tube heat exchanger.
High temperature resistance: the binder and filler of coating are comprised of heat resisting inorganic substance. Long-time temperature can reach to 600 ℃ for, short-time temperature can reach 750 ℃.
Smoothness: The ceramic packing made from multiple components show the coating a low surface energy and frictional coefficient. It can make the non-wetting between coke and surface, thereby effectively prevent heat exchanger sticky things adhere to the body. Different materials together gives excellent wear resistance, smooth anticorrosive coating performance, withstanding the high speed impact of flue gas dust and air flow scouring.
Thermal Shock Resistance: the temperature of flue gas is always changing. With high thermal shock resistance, the coating does not fall off or generate a crack when the flue gas temperature changes.
Long Service Life: the coating use nanometer materials, with long service time, good durability. Damaged coating can easily be repaired. It won’t produce pollution to the environment during preparation, painting and coating.
