Diaphragm cells monopolar electrolyzer

In the United States, 76% of the chlorine produced is from diaphragm cells. Production is equally divided between bipolar and monopolar electrolyzers. 

The voltage drop in each monopolar electrolyzer is equal to the voltage drop of a single cell. This depends primarily on the type of cell, the current density, and the choice of membrane or type of diaphragm. The number of electrolyzers contained in a cell line then fixes its total voltage. The design voltage must be sufficient to allow for losses in buswork and interceU connectors, the maximum current density to be used, and the deterioration with time of the components of the circuit. 

Control of the flow(s) to each electrolyzer frequently is manual, with the aid of rotameters. This is especially true in monopolar installations with large numbers of electrolyzers. Monopolar diaphragm cells have essentially one chamber each for anolyte and catholyte and only one feed line (for brine). They rely on division of the feed brine... 

With a monopolar circuit, the usual technique is to employ a mobile switching device that can be brought into position adjacent to the appropriate electrolyzer. With diaphragm cells, this takes the form of a cabinet on wheels, placed in the aisle next to the cell. With membrane cells, the switch may be above, below, or beside the cell. Depending on the arrangement of intercell connectors, it may be necessary to switch two electrolyzers fixim the circuit, but the principle remains the same. 

Electrolyzers for the production of chlorine and sodium hydroxide, including both diaphragm and membrane cells, are classified as either monopolar or bipolar. The designation does not refer to the electrochemical reactions that take place, which of course require two poles or electrodes for all cells, but to the electrolyzer construction or assembly. There are many more chlor-alkali production facilities with monopolar cells than with bipolar cells. 

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