The choice of materials for parts of equipment that come into direct contact with materials is an often overlooked but crucial aspect of scientific knowledge. While it doesn't directly participate in the process reaction, it fundamentally affects product safety and equipment lifespan.
In the acidic, humid, and hot environment of animal fat refining, ordinary carbon steel is prone to corrosion, leading to the migration of iron ions into the fat. This not only accelerates the oxidation and rancidity of the fat but also poses a risk of heavy metal contamination. Critical contact parts of compliant equipment, such as the inner walls of cooking tanks, conveying pipelines, and separator hoppers, generally use food-grade stainless steel, especially 304 or 316L stainless steel. These two materials have high chromium and nickel content, forming a dense passivation film that effectively resists corrosion. 316L, with the addition of molybdenum, has even stronger resistance to chloride ion corrosion and is suitable for areas with hard water. The manufacturing process of the equipment, such as the smoothness and absence of dead corners in welds, directly affects the ease of cleaning and the risk of microbial growth. Smooth inner surfaces and rounded corner designs facilitate thorough cleaning and meet hygiene standards for food safety production. From a long-term operational perspective, although high-quality materials and excellent manufacturing increase initial costs, they reduce losses from production downtime and product scrap due to corrosion and leakage, resulting in better overall economic performance.
