Production device of PVA multi-product polymerization system

Abstract

The invention discloses a production device of a PVA multi-product polymerization system, belonging to the field of chemical engineering. The system device comprises the following main equipment: a polymerizing pot 1, a polymerizing pot 1 resin pump, a polymerizing pot 2, a polymerizing pot 2 resin pump, a polymerizing column 1, a polymerizing column 1 pot pump, a PVAC storage tank, a polymerizing preheater, a mixer, a polymerizing pot 1 agitator, a polymerizing pot 1 jacket, a polymerizing pot 2 jacket, a polymerizing pot 2 agitator, a nitrogen gas buffer tank, a water seal pressurizing tank, a column 1 level control valve, dissolution methanol, a pot 2 outlet liquid mixer, a column 1 pot outlet resin mixer and a polymerizing column 2. The equipment is interconnected through pipelines. The technical scheme of the invention can realize integrated control of a multi-product production process as well as safe and quick control of a product transformation process. The product transformation process needs not reduction in amount and can maintain the maximum amount as design. Meanwhile, an SIS system can satisfy treatment under special working conditions and ensure safety of a polymerization process.

Description

Technical field [0001] The invention belongs to the chemical industry field, and particularly relates to a PVA multi-variety polymerization system production device. Background technique [0002] Polyvinyl alcohol is a very unique water-soluble high molecular polymer, it has many excellent basic properties, which makes it have a very wide range of uses in real life. Polyvinyl alcohol has good solubility and viscosity. Its aqueous solution is transparent and has good adhesion. It is not only soluble in water, but also soluble in polar solutions containing hydroxyl groups (glycerol, ethylene glycol, acetic acid, acetaldehyde, etc.). Polyvinyl alcohol is miscible with starch, plastics, synthetic resins, cellulose derivatives and various surfactants and has good stability. At the same time, polyvinyl alcohol can be regarded as a linear polymer with secondary hydroxyl groups. The secondary hydroxyl groups in the molecule have high activity and can carry out typical chemical reactio...

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Problems solved by technology

[0005] The disadvantage of this production method is that it is not easy to stir evenly for materials with high viscosity, high degree of polymerization, and high polymerization rate, especially for materials with a degree of polymerization above 2800, local agglomeration and rod climbing are easy to occur when stirring, And the axial rotation torque is too large, the stirring shaft is safe and easy to break, and the stopping of stirring will cause the phenomenon of explosion, which seriously affects the safety of production

At the same time, the feeding amount of vinyl acetate will be reduced to different degrees to ensure the safe operation of the polymerization kettle stirring. The liquid level control of one kettle of the polymerization kettle will return the polymerized material to the polymerization kettle, which changes the polymerization residence time and is easy to cause local The reaction is violent, the phenomenon of implosion occurs, and the viscosity of the material determines the limitation of the selection of polymerization equipment, the utilization rate of the equipment decreases, and the relative consumption increases

The second polymerization tank is fed to the first tower. Due to the high viscosity, methanol is added to the pipeline for dilution, but the diluted methanol and PVAC solution are mixed unevenly. After entering the first tower, the corresponding amount of blown methanol is increased, which increases energy consumption. The concentration of the PVAC solution is adjusted by adding dissolved methanol (generally, the concentration of PVAC is controlled at about 25---33%). The dissolved methanol and PVAC solution are mixed unevenly and sent to the storage tank for subsequent units to produce polyvinyl alcohol products. The concentration changes Will directly affect the quality of polyvinyl alcohol products

When driving in winter in the lower temperature northern region, it takes a long time to produce qualified PVAC, and the variety of polyvinyl acetate solution required for the production of polyvinyl alcohol products is relatively narrow. Generally, most of them are suitable for spinning. The accumulation of aldehydes will cause the quality of the product PVA to drop significantly

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