DETECTION OF DAMAGED MEMBRANES IN ALKALI CHLORIDE ELECTROLYSERS

Holes in cation exchange membranes of alkali chloride cells can have a number of different causes. They do not represent a source of great d anger during operation of a membrane electrolyser as long as their num ber is limited or their combined diameter does not exceed a certain si ze. Of the different methods for detection of holes in membranes, two procedures are described in detail: the cell voltage test and the leak test with measurement of the gas flow through the holes. The cell vol tage test is performed with low time consumption during start-up of an electrolyser. It mainly shows the large membrane holes in a cell. In contrast to this, with the leak test all holes in a membrane are detec ted. However, the procedure is time consuming and is possible only wit h a totally drained electrolyser. It is recommended to perform these t ests immediately after installing new membranes and then from time to time in order to avoid damage to the cells or to the plant chlorine sy stem.