Green Silicon carbide grain for desulfurization nozzles
Green Silicon carbide grain for desulfurization nozzles is the main material for silicon carbide spray nozzles. In fossil-fuel power plants and large boilers, silicon carbide ceramic nozzle is an important part of a wet desulfurization spray system. The gas generated in power plants or boilers contains a large amount of SO2, which seriously pollutes the environment. In today’s increasing emphasis on environmental protection, thermal power plants are adding desulfurization devices before gas emissions to reduce SO2 emissions. As a key component of the desulfurization system, silicon carbide should have strong oxidation resistance, corrosion resistance, and durability when in long-term contact with corrosive gases such as sulfur dioxide, sulfite, sulfuric acid, and absorbent slurry.
At present, green silicon carbide grain and powder are mostly used as the main raw material for silicon carbide spray nozzles in desulfurization systems. It has the following advantages:
Green silicon carbide has excellent chemical stability and corrosion resistance. Green silicon carbide grain has very stable chemical properties below 1600 degrees Celsius and will not react with strong acids. Under the action of acid and alkali, a layer of silica protective film will be formed on the surface to prevent further oxidation. So, the silicon carbide nozzle can withstand the harsh working environment in the absorption tower.
Green silicon carbide has high wear resistance and long service life. Green silicon carbide has high mechanical strength, with a microhardness of 33-34GPa, slightly lower than diamond. The wear resistance is dozens of times higher than that of alloy steel, stainless steel, and wear-resistant cast iron. Therefore, the desulfurization spray tower using silicon carbide nozzles can achieve production connection without causing economic losses due to shutdown and maintenance.
Green silicon carbide grain has excellent thermodynamic properties. Silicon carbide has excellent thermal shock resistance and is itself a good refractory and high-temperature resistant material. Green silicon carbide has the characteristics of good thermal shock resistance, low thermal expansion rate, and good thermal conductivity. Therefore, the produced silicon carbide ceramics have small deformation and high durability in high-temperature environments.
The appearance of the silicon carbide nozzle is black, but the raw material is green carborundum grain and powder. Because the purity of green silicon carbide is higher than that of black one. The hardness and physicochemical properties are also better. Thus the performance of silicon carbide ceramic parts produced from green SiC is superior. According to different production processes and formulas, most formulas adopt green carborundum powder with 240# and 1200# grits. Another formula is based on green silicon carbide grains with 90#, 150#, 180#, and 240#.
