Precautions for modifying the membrane pole pitch in electrolyzers
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This post was last edited by sunjl1981 on 2013-1-6 at 19:50. Due to the need to reduce energy consumption and emissions, many chlor-alkali manufacturers have begun to carry out modifications to change the membrane electrode spacing (to zero spacing in foreign countries). Here are some points to keep in mind during these modifications for discussion: (1) When converting electrolyzers with low current density to those with membrane (zero) electrode spacing, it is best not to increase the current density or production volume. Restricted by external pipelines, instruments, and equipment, the main goal should be energy savings； (2) Converting high-electrode-density electrolyzers to a membrane (zero) electrode spacing can help increase production capacity and save energy; however, it is necessary to check that the material used in the catholyte circulation system is of grade SUS310s or higher ； (3) To convert it into a membrane (zero) pole distance electrolyzer, a polarization rectifier is required, and operation must be carried out in accordance with the membrane (zero) pole distance operation manual ； (4) Electrolyzer modification is a systematic project; before adjusting the membrane pole distance, it is necessary to diagnose the system. In some cases, the system may require cleaning or minor modifications before the membrane pole distance can be adjusted. Otherwise, the power consumption will continue to rise over several months after the modification, until it returns to the level before the modification. What other precautions should we consider? Let’s discuss: hcbbs hcbbs
With the modified electrolyzer, it’s not true that the higher the cell temperature, the better – as long as the current efficiency meets the requirements, that’s all that matters. Remember this well
Care should be taken when modifying the membrane pole spacing in electrolyzers. There are few that meet the standards in the country. It’s usually okay at first, but it deteriorates after two years. The best option is chlorine technology, but it’s too expensive, so it isn’t very cost-effective. I hope there are companies in China that can match them! Refuel Beihua Machinery!
Friend on the 3rd floor, is that really the case? My company has this intention, but we’re still undecided. I hope you can share more of your experience. Thank you
The problem is that after some time, the spring loses its elasticity or parts of it come off, resulting in an increase in the slot voltage. Moreover, the cathode mesh is easily damaged during membrane replacement, which shortens its lifespan. If your battery has been in use for less than 10 years, it is recommended not to make any changes, unless your power consumption is very high.
Reply to 4# limingshuguang: Let’s communicate more with each other! System diagnosis before renovation is very important.
Currently, in China, the companies most capable of upgrading membrane-gap electrolyzers are Beihua Machinery and Chlorine Engineering. It is recommended that manufacturers planning such upgrades conduct thorough investigations into their track records as well as the actual operational performance of these upgrading companies.
Our company initially also planned to make modifications, but later, considering the costs as well as the stability of operation and control, we decided not to make any changes for now. We are currently replacing the membranes gradually, while maintaining a high electric density for the time being.
At present, many manufacturers operate ion exchange membranes until the electrode plates need to be recoated, and quite a number of them use a zero-electrode-distance configuration. However, after 1–2 years of operation, pinholes in the membrane occur frequently; such pinholes can appear even during planned shutdowns. In the case of unplanned, abnormal shutdowns, even more pinholes form. The presence of numerous pinholes leads to higher levels of NaCl and NaClO3 in the alkali solution, which in turn accelerates the corrosion of the anode coating and the substrate. Limited use of this technology is feasible, but large-scale application requires evaluation, including a comprehensive analysis of operating costs as well as the costs associated with electricity consumption, membrane replacement, and electrode plate recoating
The modification of membrane-electrode distance cells should be the direction of development, but many operational aspects require time to be verified: 1. The service life of the equipment materials, especially that of the ion membrane. Due to the excessive small spacing, the cushioning effect of the original membrane is lost, which makes perforations very likely to occur and leads to unnecessary accidents ； 2. The requirements for operational skills have increased, which poses a significant challenge, especially for skilled workers who are accustomed to the previous operating methods. The slightest carelessness can lead to significant losses ； 3. Key process parameters: such as tank temperature, current, processing volume (flow rate), etc. Key inspection points, inspection intervals, and maintenance intervals all require one or several operating cycles to accumulate experience and revise the procedures accordingly. 4. … Personally, I believe that resolving the above issues requires time and experience; the ion membranes used for the membrane electrode spacing could also be improved as a result. If the above problems are resolved, the technical level of ion-exchange membrane caustic soda will see another significant improvement.
Our company has upgraded several units, and the results have been good. Currently, the current density is 5.5 ka, and the slot voltage is below 3.05; some of them have been in operation for over a year. The energy-saving effect is significant.