Is there any expert in chlor-alkali instrumentation who can come and provide some guidance?
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This post was last edited by sunjl1981 on 2013-1-6 at 20:14. I would like to ask what considerations should be taken into account when selecting instruments for the chlor-alkali industry, such as media like dry/wet chlorine gas, alkaline solutions, and NaClO. What aspects need attention regarding the membrane material and filling material of transmitters? For control valves and shut-off valves, what materials should be chosen for the valve cores, valve stems, and valve seats, and what issues need to be considered? Additionally, what considerations are necessary when selecting temperature instruments and flow meters? Thank you in advance; I hope you can share your insights. This post was last edited by yzhms on 2009-2-26 at 13:17. ] # ， ， &
The questions raised by the original poster are enough to form a high-quality paper.;L It’s really impossible to discuss them all, so I’ll only talk about those I’m familiar with: 1. The difference between dry and wet chlorine lies in their water content; for wet chlorine, titanium or PTFE diaphragms can be used, while for dry chlorine, an isolation tank can be employed – after isolating it with fluorine oil, instruments can then be installed； 2. For instruments related to sodium hypochlorite, temperature is commonly used as a measuring parameter, with titanium being the material of choice in most cases ； 3. At present, in chlor-alkali applications where corrosion is a concern, valves lined with PTFE are primarily used, including control valves ； 4. Ordinary materials are sufficient for hydrogen ； 5. The flow meter can be configured based on actual conditions – it can be operated remotely or via on-site control; the material to be used should be selected according to the manual ； 6. Currently, there are diaphragm-type pressure and level measurement devices used in the chlor-alkali industry; those we use are mainly made of tantalum and are suitable for various corrosive media ； 7. Ha, there’s too much to say; let’s discuss it together, hehe. :handshake
Pressure gauges are mainly diaphragm-type, and the most important factor is the material of the diaphragm; tantalum is commonly chosen for this purpose. There are also titanium, Hastelloy C, and others. Valves can be selected with fluorine-lined options. This post was last edited by yzhms on 2009-2-26 17:08]
“For instruments related to sodium hypochlorite, temperature is a parameter that is often monitored, and titanium is generally the material of choice. Since sodium hydroxide is also present in sodium hypochlorite, shouldn’t titanium not be used in such cases? Will corrosion occur?
Any type of caustic soda should work; there shouldn’t be any problem
The cooling coil in our hypochlorous acid reaction tank is made of titanium. However, I asked about it a couple of days ago, and the instrumentation team also said it seems to be made of stainless steel; it seems we need to verify this again. Hehe.
The information on the 2nd floor is quite comprehensive; different materials for instruments, valves, etc. need to be chosen depending on the level of corrosion. Generally, you can submit your requirements regarding the medium, temperature, and pressure to the supplier, and they will help you select the appropriate instruments.