Discussion on the material for ion-exchange membrane caustic soda pipelines
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This post was last edited by sunjl1981 on 2013-1-6 at 23:21. The caustic soda coming out of the cathode of the electrolyzer is at a relatively high temperature; many design firms use nickel for the pipelines designed to handle such high-temperature caustic soda, but this material is expensive, and no other materials are available for use in such pipelines # + + .
There are probably no nickel pipes for the alkali stream coming out of the electrolyzer. The cathode circulation system generally uses 310S, 316L is used for systems that discharge material, and 304 can also be used.
Are there any suitable non-metallic pipes available now?
Depending on the type of electrolytic cell, non-metallic pipes such as fiberglass-reinforced PTFE pipes or imported reinforced polypropylene pipes are required for most imported cells, while for domestic cells, Ni or 301S pipes are required.
The material to be used for pipes should be determined based on the temperature and concentration of caustic soda. Generally, when the temperature of 50% caustic soda is above 80 degrees Celsius, low-carbon nickel N6 should be used; when the temperature is below 80 degrees Celsius, 316L is sufficient. For 32% caustic soda, 310S is appropriate when the temperature is above 80 degrees Celsius, while 316L is suitable when the temperature is below 80 degrees Celsius. When the temperature is below 50 degrees Celsius, 304 will suffice. These materials differ only in their nickel content: N6 has a nickel content of over 99%, 310S consists of 0Cr25Ni20 with a nickel content of 20%, 316L is made of 00Cr17Ni14Mo2 with a nickel content of 20%, and 304 contains 0Cr18Ni9 with a nickel content of just 9%. (Please refer to \"Physical and Chemical Constants of Chlor-alkali Products\")
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Today, high-quality PTFE pipes have an improved heat resistance, with a maximum temperature tolerance of up to 230 degrees Celsius, which is sufficient to meet the requirements of ion-exchange membrane caustic soda production.
For non-metallic materials, CPVC or PP will do; we have been using CPVC for 7 years now
Typically, the interior material of the cathode chamber in our ion membrane electrolyzers is nickel, in order to prevent corrosion by high-concentration and high-temperature caustic soda.
No way, tweezers are generally not used. The electrolyzers produced by Asahi Kasei and Kitakata Seiki usually use 310S material, while foreign electrolyzers employ plastic pipes such as PP-H and similar materials
Use CPVC for non-metallic materials, but opt for products from reputable manufacturers to ensure quality.