Chlor-alkali industry Japan

J. L. Hurst, ImplementingMembrane Cell Technology Within OuyChem Manufacturing International Symposium on Chlor—Alkali Industry, Tokyo, Japan, April, 1988. 

In the past 30 years, a new process has been developed in the chlor-alkali industry that employs a membrane to separate the anode and cathode compartments in brine electrolysis cells. The membrane is superior to a diaphragm because the membrane is impermeable to anions. Only cations can flow through the membrane. Because neither Cr nor OH ions can pass through the membrane separating the anode and cathode compartments, NaCI contamination of the NaOH formed at the cathode does not occur. Although membrane technology is now just becoming prominent in the United States, it is the dominant method for chlor-alkali production in Japan. 

Perfluorinated membranes based on weak acid functions have been developed by Asahi Chemicals (Japan). Their EW is similar to that of the above membranes. The exact synthesis process of the membrane is not indicated. They have been developed for the chlor-alkali industry where they are used in bilayer membranes. In these membranes a strongly acidic membrane (-SO3H) (pK < 1) is coated on one side, and the second side is coated with a thin layer of a weak-acid membrane (-COOH) = 3). 

Asahi Chemical Membrane Chlor—Alkali Process, Asahi Chemical Industry Co., Ltd., Tokyo, Japan, 1987. 

D. Berger, Membr. cells for chlor-alkali elctrolysis, J. Appl. Electrochem., 1992, 12, 631-644 F.Y. Matsuda, Recent development of the chlorine industry in Japan, J. Appl. Elecrochem., 1986, 16, 317-331. 

Since the first membrane cell installation at the Nobeoka plant by Asahi Chemical Industry in 1975, several membrane cell plants have been constructed, especially in Japan, as a pollution-free chlor-alkali process. By the end of 1982, the total capacity of the membrane cell process in the world was estimated to be about 600,000 tons of NaOH per year.112... 

H. Aikawa, Chlor-Alkali Technology Seminar, Japan Soda Industry Association, Tokyo (1999). 

World trade Most chlor-alkali electrolysis plants are situated in the vicinity of the chlorine users. The alkali users, particularly the alumina and pulp paper industries, are placed in the winning regions. Like the world trade with chlorinated hydrocarbons there are flows of liquid caustic soda with a volume between 2 and 3 million tonnes of NaOH (100%) per year. The net exporting regions are and will remain North America, the Middle East, Japan and Western Europe. Importing regions are South America (Surinam, Venezuela), Australia and South East Asia. 

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