Industry of chemical & synthetic chemical fiber
In the industry of chemical fiber and synthetic chemical fiber, the stainless steel equipments have the double function of anti-corrosion and pollution preventing.
1. Nylon
In the production equipments for producing Nylon 66, apart from that Al is used in the filling equipments, austenite stainless steel, mainly TP347、00Cr18Ni13Mo3、TP316L, etc. is adopted in the whole production system equipments. For example, TP347 is used to make devices including the adjusting slot of nylon salt solution, evaporation tank, steam pressure concentrating tank, cooling canister, nylon dumping storage tank, melting room, etc. The filature pipe head is manufactured with 00Cr18Ni13Mo3.
In the nitric acid oxidation technique of producing diamine material, the reactor is made of TP321.
Nylon 6 has many ways of producing; in the phenol method used in the early days, the main equipment material is stainless steel for the purpose to prevent the contamination to products by metal ions. For example, TP316 is used in the super position equipment for ∈-synthetic fiber.
2. Polyester fiber.
Of the Polyester fiber production, the ester exchanging way of DMT was used in the early days and in recent years, the direct titanic acid superposition method was invented. The accelerant for alcoholization of titanic acid and methanol is sulphuric acid, and the esterify reaction is operated under high pressure (3.5 atmos); in order to prevent the adverse side reactions, stainless steel is used in the equipment material that contacts the polymer.
3. Acrylic ester fiber.
The medium condition for producing acrylic ester fiber is rather complicated, which commonly consists of stainless steel, porcelain enamel as the equipment material. Detailed reports are rare.
4. Dyeing Industry
The material of dyeing mechanical equipment is stainless steel, these material can deal with the corrosion of all the dye liquor and bleaching liquid, and have the function of pollution prevention. Among them, in most cases, 0Cr17、 TP304 and TP316 are adopted by the reverse dyers。