Chlor-alkali plant flowsheet

The unit operations in a commercial chlor-alkali plant can be generally classified as follows (1) brine purification, (2) electrolytic cells, (3) H2 and Cl2 collection, and (4) caustic concentration and salt removal. In this section, the general process flowsheets for diaphragm, membrane, and mercury cell technologies are discussed with emphasis on the need for brine purification and the manner in which it is carried out. 

Figure 3. Flowsheet of typical diaphragm-type chlor-alkali plant.

Hgure 12.9 is a flowsheet for a system with two stages. Mechanical pumps can achieve die ratios required in chlor-alkali plants in a single stage. 

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