Page 267 - Chemical engineering design

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CHEMICAL ENGINEERING
5.5. A polymer is produced by the emulsion polymerisation of acrylonitrile and methyl
methacrylate in a stirred vessel. The monomers and an aqueous solution of catalyst
are fed to the polymerisation reactor continuously. The product is withdrawn from
the base of the vessel as a slurry.
Devise a control system for this reactor, and draw up a preliminary piping and
instrument diagram. The follow points need to be considered:
1. Close control of the reactor temperature is required.
2. The reactor runs 90 per cent full.
3. The water and monomers are fed to the reactor separately.
4. The emulsion is a 30 per cent mixture of monomers in water.
5. The flow of catalyst will be small compared with the water and monomer flows.
6. Accurate control of the catalyst flow is essential.
5.6. Devise a control system for the distillation column described in Chapter 11,
Example 11.2. The flow to the column comes from a storage tank. The product,
acetone, is sent to storage and the waste to an effluent pond. It is essential that
the specifications on product and waste quality are met.