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Cooling Tower Mainteance Corrosion inhibitors for cooling water systems are very important – it’s no secret that cooling circuits quickly deteriorate unless they are properly maintained and cared for. And it’s also common knowledge that cooling tower maintenance requires a range of carefully matched chemicals. Find out more about conditioning cooling water here:
Corrosion inhibitors for cooling water systems solve some of the major problems in cooling towers. Generally, cooling tower operators face four problems that must be solved with additives to the water. They are all interconnected in some way and interact to a greater or lesser degree.
A range of conditioners are available for each problem and with varying effectiveness, depending on how well-suited they are to a particular issue.
Water either corrodes or forms deposits. Depending on its composition, water contains a certain amount of dissolved solids such as calcium and magnesium which are suspended in carbon dioxide. When water is heated, carbon dioxide is decomposed and calcium (actually, all dissolved salts) begin to precipitate and form deposits in pipes or heat exchangers.
This isn’t necessarily a bad thing – the deposits protect metal against corrosion. HOWEVER, they also reduce the heat transfer coefficient (k value) in the heat exchanger. In turn, this reduces the plant’s performance and effectiveness considerably. Of course it’s possible to desalinate the cooling water to prevent calcification, but then you can practically watch the metal corrode in real-time and risk overusing corrosion inhibitors for cooling water systems etc.
Modern water stabilisers for cooling tower scale removal like phosphates can’t prevent calcium from precipitating, but they do prevent it from forming scale and crystals. After using a cooling tower descaler, calcium is kept in suspension, allowing it to be flushed out of the circuit with the blowdown. The calcium suspended in the water is actually good for the system, because it prevents corrosion in cooling water systems.
Wherever soft water is used in cooling towers – no matter whether it is surface water or desalinated water – corrosion inevitably follows. All metals are affected to a greater or lesser degree. Even stainless steel will succumb in time. The advantage is that the heat exchanger always achieves optimal thermal conductivity, as there are no deposits to prevent heat transfer.
But in that case it is mandatory to protect the system against aggressive water of this kind. This is accomplished with a cooling water corrosion inhibitor or an anti-corrosive which cover all metal surfaces with a thin protective layer – without the insulating effect of calcification. Ideally, a phosphonate is chosen as it protects against corrosion and acts as a hardness stabiliser. Corrosion inhibitors for cooling water systems do this by keeping calcium suspended in the water, preventing it from crystallising and thus protecting metal surfaces. Excess calcium is then flushed out of the circuit during blowdown.
The moment water comes into contact with air, it begins to accumulate dust, soot, insects, pollen, leaves and so forth. This is because a cooling tower acts like a gigantic air scrubber. Floating in the water and aided by vortices, these dissolved solids precipitate at critical junctures throughout the system.
At some point, these sediments prevent water throughput and displace cooling water from the compensating reservoir.
Naturally, it is possible to remove the sediments mechanically on a regular basis – for example, by using shovels, sludge extractors and water jets during annual maintenance. However, a simpler solution is to prevent the formation of these sediments in the first place. Sediment and corrosion inhibitors for cooling water systems / dispersant for cooling tower keep deposit-forming solids suspended in the water and prevent them from settling on surfaces. Like calcium, they get flushed out of the system during blowdown before they can contribute to blockages or throughput issues.
Cooling tower corrosion inhibitor Sanosil Corfit A and Corfit B each combine stabilisers, cooling water corrosion protection and dispersion in one useful, efficient recipe.
Bacteria are number four of the bothersome quartet and thrive in warm cooling water. They form slimy layers which prevent heat transfer and can drift, causing blockages in pipes and pumps. As if that weren’t bad enough, warm water in a cooling tower can become a habitat in which legionella and other harmful bacteria can flourish.
Adding a biocide or disinfectant keeps these bacteria in check and prevents slime and algae from forming. Additionally, it protects the vicinity from dangerous aerosols containing microorganisms. This enables a technically and legally sound operation of cooling towers.
Sanosil C is an excellent biocide for cooling circuits. It is fast-acting, reliable and long-lasting against biofilms and microbes in water.
Plus, it is an excellent companion for the corrosion inhibitors for cooling water systems Corfit Protect B and Corfit Protect A or Corfit Bright, Corfit Closed Al, Corfit Closed Std, Corfit Initial, for stabilising, corrosion in cooling water systems protection and dispersion.
