20 YEARS DEVELOPMENT OF A BIPOLAR MEMBRAN E CELL FOR ALKALI CHLORIDE ELECTROLYSIS FROM LABORATORY TO GLOBAL APPLICATION

First samples of perfluorinated cation exchange membranes were obtaine d in 1971. They were tested for use in the diaphragm process as a repl acement for asbestos diaphragms. However, the special features of thes e membranes led to the decision to develop special new membrane electr olysis cells. A patent was sought for the first new cell design in 197 5. After extensive material testing and many improvements, the HOECHST bipolar membrane cell was produced, consisting of an electrolyzer mad e up of individual elements, i.e. individual sealed electrolysis cells . Starting in 1982, this cell type was developed further in cooperatio n with UHDE GmbH. In 1983 it was installed for the first time in an in dustrial electrolysis plant. Despite strong competition, the bipolar H OECHST-UHDE membrane cell has now gained an important market share. In 1998 it will be installed worldwide in 43 electrolysis plants, with a total NaOH capacity then amounting to 2.5 million mtpa.