Cooling towers are important and vital equipments for the operations of various processing industries at large. This cooling process is very important for the processing industry, chemical industry, oil and gas industry (oil refineries and petrochemicals), biofuel and biorefinery industries, power plants (fossil fuel and biomass), geothermal and large-scale (hyperscale) data centers. With the process conditions achieved, the industry can produce products that are economical/efficient and stable.
The cooling medium in the industry or factory is water, and the water is cooled in a cooling tower. And air from the atmosphere is used to cool warm water from industrial or factory processes through this cooling tower. This results in direct contact between air from the atmosphere and the warm water to be cooled. This is a source of pollution for the cooling tower water. A certain amount of additional water (make-up water) also needs to be added to replace lost water such as blow down, leaks and so on.
With continuous 24-hour operation for almost a whole year with a large volume of circulating cooling water, up to thousands of tonnes/hour, it is certainly not a simple matter to be able to maintain good and stable water quality. If water quality cannot be maintained, a number of serious problems will arise. A number of problems for cooling tower operations such as corrosion, scale, layers formed by green algae, organic materials and a number of micro organisms will reduce the performance of the cooling tower. If this happens, heat exchange will be disrupted and energy requirements for cooling tower operations will increase. When the cooling process does not work as it should, it will also affect product quality and the durability of production equipment, in the extreme case, if the cooling tower does not function, the industry or factory will stop operating (shut down).
If the cooling tower is damaged or has low efficiency, such as due to scale, there will be a low heat dissipation effect and a lot of energy loss. Then rust causes the pipe to become brittle and leak, resulting in a short life span for the pipe. Then the appearance of green algae, moss and mud from the accumulation of organic material, these things will disrupt the flow of water and even block pipes and valves. Another nuisance is the presence of bacteria and especially legionella (pathogenic bacteria that cause legionellosis) which causes various health problems.
Cold water as the output/product of the cooling tower will be used as a cooling medium in industry or factories such as condensers or other heat exchangers. The layer of fouling formed by scale on the surface of the heat exchanger ultimately reduces the overall heat transfer coefficient. In general, about 15% of energy is lost each year due to a decrease in heat transfer efficiency caused by fouling. Therefore, it is necessary to replace the pipes periodically every 3 to 5 years, and that is not a cheap cost. Even if the fouling problem is not controlled, heat loss can reach up to 70% after five years of operation.
If a problem occurs, repairs need to be carried out and often cooling tower repairs are expensive. A number of improvements/repairs to the cooling tower include structural repairs, replacement of mechanical components, drift eliminators, water distribution and fill types. Apart from the design problems of the cooling tower equipment manufacturers, water quality problems greatly affect the performance and lifespan of the equipment. This means that one solution is that efforts to maintain water quality must be maximized.
AOP (advanced oxidation process) technology has become the focus of developed countries to maximize water quality, including water as a cooling medium that is processed in cooling towers. AOP technology provides complete sterilization without leaving toxic residues and exhibits much stronger oxidizing power than conventional oxidants such as chlorine, chlorine dioxide and potassium permanganate. AOP technology specifically designed for reaction speed and intensity will be very effective for this purpose.
Compared to chemical treatment, although chemical treatment is still commonly used, there are restrictions due to environmental pollution and formaldehyde production, as well as because workers are exposed to serious dangers. As the restrictions on environmental pollution by respective governments become increasingly stringent, the use of chemicals will become increasingly restricted. Several developed countries are starting to control the addition of chemicals. The Singapore government has banned the addition of chemicals to cooling towers since 2008.
If you are interested in knowing AOP technology and its application for cooling tower water conditioners, please contact: eko.sbs@gmail.com
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