Equipment Polymerisation reactors

Monomer emulsions ate prepared in separate stainless steel emulsification tanks that are usually equipped with a turbine agitator, manometer level gage, cooling cods, a sprayer inert gas, temperature recorder, mpture disk, flame arrester, and various nossles for charging the ingredients. Monomer emulsions are commonly fed continuously to the reactor throughout the polymerisation. 

The synthesis of the high molecular weight polymer from chlorotrifluoroethylene [79-38-9] has been carried out in bulk (2 >—21 solution (28—30), suspension (31—36), and emulsion (37—41) polymerisation systems using free-radical initiators, uv, and gamma radiation. Emulsion and suspension polymers are more thermally stable than bulk-produced polymers. Polymerisations can be carried out in glass or stainless steel agitated reactors under conditions (pressure 0.34—1.03 MPa (50—150 psi) and temperature 21—53°C) that require no unique equipment. 

The suspended droplets of liquid monomer are progressively converted to solid or porous PVC particles. Unreacted VCM is stripped from the polymer and water is separated by centrifuging. The polymer is then dried, typically in fluidised bed drying equipment. Prior to start-up of the next polymerisation cycle, the reactor is cleaned and coated with an antifouling agent. The mechanism of action of antifouling agents has been studied (149). 

The individual suspension PP processes of various manufacturers differ with respect to process conditions and equipment employed. In modem PP suspension processes the polymerisation of homopolymers and random copolymers takes place in liquid propylene (bulk polymerisation). The polymerisation can be continued in one or several gas phase reactors, especially when impact copolymer is produced. Examples of these types of processes are ... 

The unconverted VCM is vented-off to a gas-holder or straight to a VCM recovery unit, before stripping operations. The objective is to reduce the pressure close to atmospheric. Because of the surfactants or emulsifiers present in PVC water mixture, the reactor contents are liable to foam during this venting process, especially in the emulsion process. This removal of unconverted monomer can be performed either in the polymerisation vessel itself, or in a blowdown tank. Some t5q)es of vessel will be equipped to catch any carry over, should it occur. 

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