Polyacetal production process flow

This is too difficult. Even if there are people, no one dares to put it up. It is probably a principled process that can be put up.

Polyoxymethylene (POM) is divided into two categories: One type is a homopolymer of trimerformaldehyde or formaldehyde, which is called homopolymer, and the other type is a copolymer of trimerformaldehyde and a small amount of cyclic form, which is called copolymer. The production process of homopolymer is represented by DuPont. Its product has a relative density of about 1.4 and a melting point of 170-185°C. It is characterized by excellent rigidity and a tensile strength of up to 68.9MPa. The tensile strength per unit mass is higher than that of zinc and brass. It also has good wear resistance and small friction coefficient, but has poor thermal stability and is not acid-resistant. In the homopolymerization process, 50% formaldehyde solution is first reacted with isooctyl alcohol to generate a hemiacetal solution. Refined formaldehyde is obtained through dehydration and thermal cracking, and then liquid phase polymerization is performed in the reactor. After the polymerization product is filtered, separated and dried, it is then esterified and capped with acetic anhydride. High-purity nitrogen protection is required during the process. The formaldehyde purification and refining process of this process is complicated, and the post-processing and end-capping technology is difficult. The process flow is too long, the equipment is too much, and the corrosion is serious. Expensive alloy materials are needed to make the synthetic kettle material. The copolymer acetal production process is represented by the technology of Hoechst-Celanese Company, and BASF, Mitsubishi Gas Chemical Company, etc. also have their own technologies. Ube Kosan's gas-phase formaldehyde copolymerization process that does not use solvents during the polymerization process is also unique. Concentrate 50% formaldehyde solution to 65%, synthesize paraformaldehyde solution in the presence of sulfuric acid, and obtain polymer grade paraformaldehyde through solvent (benzene or dichloroethane) extraction and refinement. Then, using polymer-grade trimerformaldehyde as the polymerization monomer and ethylene oxide (or dioxolane) as the comonomer, a twin-screw reactor is used for bulk continuous copolymerization. The obtained copolymer is pulverized, continuously stabilized and intermittent stabilized to remove thermally unstable components, dried and then mixed with additives for granulation. Asahi Kasei has developed a new process for directly synthesizing 70% high-concentration formaldehyde through methylal oxidation, eliminating the need for formaldehyde concentration and dilute formaldehyde recovery operations. The formaldehyde produced in the synthesis of paraformaldehyde can be recycled back to the methylal synthesis reaction tower. Its methylal synthesis reaction temperature is low (60-90°C), almost no formic acid is generated, and there is no equipment corrosion. In addition, since the formaldehyde content obtained by the reaction reaches 70%, it is beneficial to increase the reaction speed of parformaldehyde synthesis and reduce side reactions. Ube Kosan's gas phase copolymerized formaldehyde technology mainly consists of formaldehyde synthesis, monomer preparation, copolymerization, stabilization, solvent recovery, etc. The process route is: The raw material methanol is produced by air oxidation to produce 50% formaldehyde. Formaldehyde reacts with polyethylene glycol and undergoes dehydration, thermal decomposition and refining to obtain refined formaldehyde gas. The refined formaldehyde gas is mixed with the comonomer trioxane in gaseous state and then enters the twin-screw reactor for copolymerization. The high-temperature circulating polyoxymethylene powder discharged from the polymerization reactor is cooled and returned to the polymerization reactor for circulation to control the polymerization reaction temperature. The polyoxymethylene powder is then sent to the stabilization treatment using a screw conveyor. This technology does not have high material requirements, has a simple process and is less corrosive. Copolymerization technology using paraformaldehyde as the polymer monomer accounts for 80% of the world's polyformaldehyde production capacity. In terms of paraformaldehyde manufacturing technology, currently the sulfuric acid catalytic method and the solid acid catalytic method coexist. The methylal oxidation developed by Asahi Kasei Company produces 70% concentrated formaldehyde, which is a major improvement in the copolymerization process route and eliminates the steps of formaldehyde concentration and dilute aldehyde recovery. * * Save energy consumption and costs. In terms of stabilization technology, melt technology and liquid phase hydrolysis technology currently coexist, and the latter has development potential.

I know that when foreign countries are currently transferring polyformaldehyde technology to China, Poland and* * Two technologies. But I don’t know who knows * * Fuyi polyformaldehyde technology background? * * Is there such technology? Can anyone comment on Fuyi International Company?

Does anyone know the process flow of polyformaldehyde production in Dongchen, Bazhou, Xinjiang? I need it urgently!

I am also interested in this and hope to see it, even if it is a principled process, learn* study *

I also want to learn* study * , learn about the polyformaldehyde production process. Our company uses 6,000 tons of polyformaldehyde a year.

Yuntianhua has copolymer formaldehyde equipment, which is a Polish process

Methanol - 40% formaldehyde - 60% formaldehyde - trimerformaldehyde (+ dioxane) - copolymer formaldehyde

I also really want to learn* Polyformaldehyde process engineering, as well as key equipment used in the process. Can the friend upstairs leave his contact information? Please ask me some questions.

What is the manufacturer and brand of polyformaldehyde?