Petroleum and chemical industries occupies a very core position in the national economy, and chemical process pumps are becoming more and more understood as a core collocation machine equipment. Due to the intertwined characteristics of chemical media and the continuous improvement of ecological and environmental protection regulations, how do we choose the model of chemical pumps? Which aspects should be paid attention to? It is particularly important. Now combine the characteristics of most chemical companies' related products to make a brief discussion on the model selection of more commonly used chemical pumps~
For a long time, erosion has been one of the most painful injuries of chemical equipment. A little carelessness can damage machinery and equipment, or cause accidents and even disasters. According to relevant statistical analysis, about 60% of the damage of chemical machinery and equipment is caused by erosion. Therefore, the rationality of the material selection should be paid attention to when choosing the model of chemical pump. Generally, there is a misconception that stainless steel plates are "all-round materials". No matter what the media and indoor environmental standards, stainless steel plates are used. This is very dangerous. Let's talk about the key points of selecting materials for some of the more commonly used chemical media:
1. Sulfuric acid is one of the strong corrosive media. Sulfuric acid is a very versatile core industrial raw material. Sulfuric acid with different concentration values and temperatures has a big difference in the corrosion of materials. For concentrated sulfuric acid with a concentration value above 80% and a temperature below 80℃, carbon steel and cast iron have good corrosion resistance, but it It is not suitable for fast-flowing sulfuric acid and is not suitable as the material of pump valves; general stainless steel plates such as 304 (0Cr18Ni9) and 316 (0Cr18Ni12Mo2Ti) have limited use for sulfuric acid media.
2. Hydrochloric acid Most metal materials are not resistant to hydrochloric acid attack (including various stainless steel materials), and high-silicon ferro-molybdenum can only be used in hydrochloric acid below 50°C and 30%. Conversely with metallic materials, most non-metallic materials have excellent corrosion resistance to hydrochloric acid. Therefore, rubber pumps and plastic pumps (such as engineering plastics, fluoroplastics, etc.) are the most suitable choice for transporting hydrochloric acid.
3. Nitric acid usually most metals are quickly eroded and destroyed in nitric acid. Stainless steel plate is the most widely used nitric acid resistant material. It has excellent corrosion resistance to any concentration of nitric acid at room temperature. It is worth mentioning that it contains The corrosion resistance of molybdenum stainless steel plates (such as 316, 316L) to nitric acid is not only worse than that of ordinary stainless steel plates (such as 304, 321), and sometimes even far worse. For high temperature nitric acid, fluoroplastic alloy materials are generally used.
