Coal-fired sulphides are best corroded with flue gas anti-corrosion coatings

China Coatings Online News Information
Coal-fired flue gas contains sulfur dioxide, sulfur trioxide, hydrogen fluoride, hydrogen chloride and other acidic corrosive gases, these corrosive media in high temperature flue gas corrosion is serious, resulting in the production of flue gas is acidic, If the temperature of the flue gas is lower than the acid dew point, the condensed acid will erode the inner wall of desulfurization, the installation of wet flue gas desulfurization (FGD) assembly can not be useful in addition to the SO3 in the flue gas, but the smoke temperature is Chinese New Year's EveChinese New Year's Eve down. Flue gas anti-corrosion coating experts pointed out that the medium of flue gas corrosion is more serious erosion tendency in FGD installation of GCH can not solve the internal erosion of flue gas desulfurization, because the temperature of reheated flue gas is still lower than the acid dew point of smoke.
sulfur dioxide in the flue gas during the desulfurization process is first absorbed and produced by sulphate or sulphuric acid, which eventually produces sulphates or sulfates. Sulphate and sulfate ions have strong chemical activity, resulting in corrosion of equipment. Sulfur dioxide absorption liquid, pH high value is conducive to sulfur dioxide absorption, pH value of 6, sulfur dioxide absorption effect is best. The low pH makes sulfur dioxide absorption inhibited, the efficiency of desulfurization is greatly reduced, when pH is 4, sulfur dioxide absorption is almost impossible, and the absorption fluid is acidic, resulting in equipment corrosion. In order to solve the problem of desulfurization of wet flue gas desulfurization pipe, we must seek a kind of acid-resistant anti-corrosion, temperature-resistant, temperature-resistant and wear-resistant adhesion and good material, flue gas desulfurization anti-corrosion coating provides us with a better choice. So far, at least, this should be the best way to solve the problem.
desulfurization anti-corrosion anti-corrosion coating with high temperature flue gas corrosion corrosion characteristics are different, flue gas emissions of flue gas general temperature of about 180 degrees C, relative humidity of 3%, containing ash and a variety of corrosive components, such as SO2, HCl, NO2 and salt spray, and even some fluorine gas containing hydrofluoric acid strong corrosion gas. In the process of desulfurization, it also has the characteristics of alternating acid and alkali quality, so the equipment corrosion is serious, anti-corrosion conditions are more demanding. In recent years, in the research and development practice of desulfurized flue corrosion coating, anti-corrosion research and development personnel have learned from the previous experience and lessons of flue gas desulfurization flue corrosion, according to hundreds of flue flue site conditions, do everything possible, bold innovation, the use of new technologies, combined with high-tech, smoke The successful application of gas anti-corrosion coating coating, the coating's amazing anti-high temperature flue gas, anti-desulfurization flue condensate corrosion effect, high temperature, high hardness wear resistance, acid resistance to alkali, good expansion coefficient, can be used for more than 10 years.
desulfurization system, SO2, H2SO4, H2SO3, HCl react quickly and eventually produce CaCl2 and CaSO4. CaSO4 solubility is very small, the SO42-concentration in waste liquid is not greater than 1000mg/L, but CaCl2 solubility is very large, so the pulp and wastewater in the Cl-concentration is very high, resulting in corrosion of equipment. When the Cl-concentration exceeds 60000ppm, expensive corrosion-resistant materials need to be replaced. Acid gases such as SO2, HCl and HF in flue gas produce corresponding acids when they come into contact with liquids, and so32-, Cl-, SO42-have a strong corrosive effect on metals and a strong diffusion penetration damage effect on anti-corrosion linings. The sulfates and sulphates in the absorption tower slurry seep into the anti-corrosion lining and its capillary holes with the solution, and gradually dry out the absorption tower when the desulfurization system is out of operation. Anti-corrosion coating research and development personnel according to hundreds of desulfurized fan corrosion site situation, the use of new technology, combined with high-tech, years of research and development, flue gas anti-corrosion coating research and development successful application. Desulfurizer flue gas anti-corrosion coating silicon inorganic polymer modified to organic polymer, the coating can be alternately arranged composed of multi-segment copolymers, in the coating space to form a two-dimensional mesh structure state, and the coating of ultra-fine powder rare earth oxidation objects in the coating to form a dense interface transition layer, in the common role effectively prevent the acid-alkali liquid on the substring attack, flue gas anti-corrosion coating coating resistance to high temperature, temperature resistance can reach 850 degrees C. Desulfurized fan flue gas corrosion-resistant coating excellent corrosion resistance, can also resist acid and alkali corrosion, anti-flue gas H2S, chloride ions, sulfur dioxide, sulfur trioxide, hydrogen chloride high temperature water vapor and other media corrosion, to prevent condensate point corrosion, stress corrosion, chemical corrosion, potemic corrosion, etc., and high line expansion coefficient, high adhesion, high impact resistance to wear. The sulfates and sulphates in the solution are delineated and crystallized, and then the volume expands, creating stress and peeling damage to the corrosion-resistant lining. Different amounts of thermal expansion of non-metallic and metallic materials cause thermal stress to form at the interface between the two. The variable stress caused by the change of air flow, the shock of liquid flow and other vibrations reduces the bonding strength of non-metallic lining and substrate material, and increases defects such as micro-cracks and pores in the lining and interface. Residual stress, thermal stress, and cross-over stress accelerate the corrosion process of non-metallic materials.
acidic and corrosive gases such as sulfur dioxide, sulfur trioxide, hydrogen fluoride and hydrogen chloride in the flue gas desulfurization pipeline will not condense into acid to corrode desulfurization, and the actual life of desulfurization is much greater than thirty years. Flue gas desulfurization anti-corrosion coatings are made of fine materials, inorganic polymer-based inter-permeable network polymers as film-forming substances of flue gas desulfurization anti-corrosion coatings, the main components of the coating using nano-powder, ceramic microbeads, silicon carbide, boron nitride, fine crystal alumina, ultra-fine zinc oxide, titanium oxide, etc., to make metal ceramic functional special fillers to improve the wear resistance, corrosion resistance. Enhance the impact resistance of the coating with inorderable fibers. Serve with appropriate pigments, solvents, additives and add wear-resistant enhancers. Flue gas desulfurization anti-corrosion coating and traditional polysulfurization, foam glass brick, glass scales, OM coating or glue, it has high temperature resistance, light coating, high hardness, long service life, good durability, service life can be up to 10 years, in the course of operation damaged coating can be easily repaired. No contamination of the environment during preparation, coating and coating. 1, flue gas desulfurization anti-corrosion coating has excellent resistance to chemical corrosion, especially condensation sulfuric acid corrosion capacity; 2, flue gas desulfurization anti-corrosion coating has very high water vapor penetration performance; 3, flue gas desulfurization anti-corrosion coating coating has excellent resistance to high temperature and temperature rapid change performance, can meet the long-term operating temperature fluctuations between 45-600 degrees C, short-term operating temperature of 800 degrees C, protection action temperature 850 degrees C;4, flue gas desulfurization anti-corrosion coating also has a higher anti-flexible and thermal expansion resistance, can resist steel desulfurization although reinforced but still inevitable vibration in operation;
flue gas anti-corrosion coating is very good protection of desulfurized metal, in the non-metallic material lining ontological solidification, the new chemical bonds and physical bonds formed by the curing reaction between large molecules, so that the polymer and composition of large molecules change, the molecular distance caused by shrinkage. However, there will be different material shrinkage rates in the lining of flue gas anti-corrosion coating desulfurization equipment, including uneven curing reaction speed and curing heat distribution of the same phase material, resulting in shrinkage residual stress.