Discussing the corrosion and protection of urban water supply pipelines
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This post was last edited by Wang Wei2 on 2019-9-10 at 11:08. Let’s discuss the corrosion and protection of urban water supply pipelines. Water itself is an electrolyte; areas with different properties on the inner surface of the pipes act as electrodes, leading to electrochemical corrosion. Electrochemical corrosion is the main mechanism of corrosion in urban water supply pipelines. Whether the pipe wall surface is clean and free of impurities has a significant impact on the rate of corrosion occurrence and progression. Dissolved oxygen, CO2, sulfates, chlorides, and residual disinfectants in the water supply process also have an impact on pipeline corrosion. The Cl- in tap water destroys the passivation film and acts as a catalyst for corrosion, inducing the hydrolysis of Fe2+ and thereby corroding the pipes. The impact of flow velocity on corrosion: Flow velocity is proportional to the speed at which oxygen reaches the metal surface; simultaneously, the flow washes away the corrosion products from the metal surface, accelerating the rate of metal corrosion and thus accelerating the corrosion of the pipes as well. Of course, the pH level of the water is also one of the factors affecting pipe corrosion.
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This post was last edited by yidiandian23 on 2019-9-20 09:07. Thank you very much to the original poster for sharing this information; it’s useful. We have previously dealt quite a lot with the detection of dissolved oxygen in boiler water, as high levels of dissolved oxygen can cause severe corrosion of the pipelines and equipment through which water flows, leading to oxygen corrosion. This also has a serious impact on the strength of metal components. Therefore, the dissolved oxygen in the boiler feed water must be measured using an oxygen analyzer.
Is water more corrosive, or is pure water more corrosive? In urban water supply, there are significant differences among tap water, reclaimed water, and wastewater. In comparison, the problems at sewage treatment plants might be greater.
This theme is very creative and original. Countries around the world are making every effort to develop sources of potable water, such as Australia, Singapore, France, the United Kingdom, and so on. In Singapore, where strict implementation is ensured, as part of an overall plan to replace different types of pipes, carbon steel pipes were replaced with PVC pipes over the course of more than 30 years; those PVC pipes were then replaced with PE pipes. The most recent replacement took place 20 years ago, when PE pipes were replaced with ABS pipes. The data from the tenth year after switching to ABS pipes are compared with those of PE pipes, PVC pipes, and carbon steel pipes. There are three aspects that deserve the most praise: (1) the system has a zero leakage rate, (2) there is a zero rate of pipe damage, and (3) there is a zero rate of bacterial attachment to the inner walls of the pipes. Therefore, in Singapore, ABS pressure plastic pipes that meet the AS3518 standards are used for public water supply pipelines. For pure water, ultra-pure water used in industry, as well as water for medical purposes, ABS pressure plastic pipes that comply with the AS3518 standard are chosen. Another material that competes with ABS pipes is PVDF; however, due to its high cost, it is rarely used in applications related to the delivery of clean water in domestic or medical settings. For pipes used to transport clean water, polar materials should be chosen to achieve a lasting solution. Plastic pipes must be ABS pressure plastic pipes that comply with the AS3518 standard; they are a polar material. Polar material, as a pipe material for transporting clean water, is the only one that can completely solve the problems associated with pipes used for supplying clean water to households ； (1) Corrosion, (2) Bacteria, (3) Dissolved oxygen,… are all easily resolved.
The successes of advanced practices abroad can serve as a model for me. Singapore’s development has been centered around the Chinese community, with excellent results. In Shenzhen, within China, one can find many miniatures of Singapore; it’s excellent and highly regarded by the Chinese people. Issues such as pipe corrosion in urban water supply systems, poor water quality, bacterial growth, and the unpleasant odor of rusty water… Using ABS pressure plastic pipes made from AS3518 for delivering drinking water to the public represents a significant contribution to the health of the population
So what are some good ways to solve the problem of corrosion?