Polyvinyl alcohol (PVA) drying

2022-05-13

Vinyl acetate is polymerized to form polyvinyl acetate. The polymer can be saponified to give various grades of flocculent, flake, granular, and powdery polyvinyl alcohol with 99.9% and 88% alcohol solvency under different amounts of alkali. The polyvinyl alcohol solution has good film-forming properties. Emulsification. Polyvinyl alcohol is mainly used for the production of synthetic fibers, plastics, adhesives, coatings, new building materials, etc., and is widely used in the chemical industry, textile, printing and papermaking, tanning industry, construction and so on.

Pva

During the production process, the final polyvinyl alcohol precipitate produced by saponification must be pressed and dried to obtain the final product. Polyvinyl alcohol is more viscous and gel-like. The evaporation rate of surface water during drying is much faster than the migration of moisture inside the material to the surface of the particles. The migration of moisture is the limiting part of the drying speed. The heat required for this type of material is not large, and the drying speed is very slow. In general, direct drying with hot air is not suitable for the drying of such materials.

At present, most manufacturers use a vacuum rake dryer to dry polyvinyl alcohol. Vacuum rake dryer only jacket is the heat transfer surface, plus the material can not fill the entire cylinder, so the jacket area is only 60% can be effectively used, which led to a very large volume of vacuum rake dryer, occupying space Large, increasing the investment in civil engineering; the movement of materials in a vacuum rake dryer cannot maintain a strict first-in, first-out principle. There are dead spots and stagnant zones, which can cause the retained materials to be heated and deteriorated and discolored for a long time.

Hollow blade dryers are improved products for vacuum rake dryers. The vacuum rake dryer can handle a wide range of materials, but most of the hollow blade dryers can also handle materials that can be processed by the vacuum rake dryer. The main improvements are:

1. Change batch operation to continuous operation;
2, improve the utilization of the heat transfer surface; reduce the equipment volume;
3, the heat transfer surface and the material full contact, update, uniform heat transfer, shorten the processing time, reduce the material for a long time heat deterioration;
4. The flow path of the material in the dryer was changed, the microscopic spiral forward, the macroscopic piston flow;
5. The equipment is easy to clean when changing material types.

Due to the characteristics of the hollow blade dryer, manufacturing level and the strength of the factory, Sanmenxia Pakide Drying Engineering Co., Ltd. won the bid for the equipment selection and bidding of a polyvinyl alcohol manufacturer in Shanxi Province, and provided a large-scale hollow blade dryer for the drying of polyvinyl alcohol.

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