Cooling is accomplished through the latent heat of vaporization. Cooling water chemistry, corrosion products and their effect. The pressure and design of a boiler determine the quality of water it requires for steam generation. Alternative water technology system for cooling tower applications.
Water treatment cooling towers, evaporative condensers. Cropper abstract amounts of iron in solution in natural water at equilibrium are related to the ph and eh of the solution. Pdf water chemistry for copper and stainless steel. Routine testing for condenser cooling water and air inleakage during suitable maintenance opportunities breatherbladdersnitrogen blanketing of makeup storage tanks checking makeup water quality prior to startup use of auxiliary steam for prompt pegging of the deaerator. Blow down removal of water from a boiler or cooling tower, to reduce water in the system with high concentrations of dissolved minerals in the water increased by evaporation and placed by water with lower dissolved solids. Cooling water problems and solutions ced engineering. Typical closed loop cooling tower system is shown in figure 7.
A cooling tower water treatment system is an arrangement of technologies that remove damaging impurities from your cooling tower feed water, circulation water, andor blowdown. Marcus neuhaus, imperial sugar company 345 keystone avenue. Cooling towerrelated water consumption is one of largest potable water loads within buildings in the united states, with substantial building water use associated with heating and cooling. The resulting lower temperature cooling water is returned to the condenser, and the amount of water that. Stator cooling water is contained in a closed loop system that cools the copper stator bars in watercooled generators. This can be achieved using carefully selected cooling tower water treatment chemicals.
There is no single solution to microbiological control in cooling systems. The basics of cooling tower water treatment the purpose of a cooling tower is to remove the heat generated by an hvac system cooling of compressor refrigerant and heat generated by the compressor itself. It is estimated that 40% of waterbased stator cooling systems operate with highdissolved oxygen and neutral water chemistry. If the stator cooling water contains oxygen, the hollow conductors release dissolved copper and or copper oxide particles that, when redepositing preferentially, may cause flow restrictions in the strands and thus impair cooling. Blowing down to maintain proper boiler water chemistry detection and reporting of main steam contamination. Cooling tower process tower basin distribution deck basin tower fill induced draft fan recirc pump return water supply water a tower cools water by evaporation by drawing high volume air across the water surface, which transfers heat to the atmosphere. This environment includes aerated cooling water, scale deposits, surface films, process contaminants, and microbiological growths. Monitor makeup and blowdown water quality to confirm that the system is behaving as anticipated.
Considerable quantities of cooling water are required in the production process of fertilizers. The dissolved oxygen and conductivity of the demineralised water are all controlled and monitored. A comprehensive cooling water treatment program using. Chemical equilibrium principles of acidsbases, dissolutionprecipitation, oxidationreduction, and complexation applied to understanding the chemistry of surface waters, groundwaters, and water and wastewater treatment. Water treatment for cooling towers 1 of 2 email a colleague. Fct water treatment provides a wide variety of products to meet any potential water treatment conditions. To ensure such cooling towers are correctly maintained and operate at optimum efficiency it is essential that the correct cooling water conditions are established and then maintained at all times. Chapter 25 deposit and scale control cooling system. Effective corrosion control relies on the ability of chemical inhibitors to retard or inhibit the chemical reaction that occurs at either the anode or the cathode. Water is used in cooling systems as a heat transfer medium and frequently also as the final point to reject heat into the atmosphere by evaporating inside cooling towers. Cooling water chemistry friend or foe plymouth tube. Pdf water chemistry for copper and stainless steel cooling. The water exits the cooling tower and is sent back to the exchangers or to other units for further cooling.
Water deliberately discharged from a cooling system to control. Cooling water problems and solutions water is used in cooling systems as a heat transfer medium and frequently also as the final point to reject heat into the atmosphere by evaporating inside cooling towers. Technical information for cooling towers using recycled water. This will best ensure the proper operation of the system, and eliminate any finger pointing regarding water chemistry. The cooling water composite curve can first be constructed from the limiting cooling water data. Nalco water will work with you to design a program from our complete line of oxidizing and nonoxidizing biocides, algaecides and biodispersants. For legionella emergency disinfection purposes, an initial 50 ppm. Kim burchtorf chemtreat corporate offices 4461 cox road glen allen, virginia 23060. Treatment and corrosion control of cooling water page 5 the main chemical factors which influence the tendency of cooling water to corrode are mineral salt content, ph value and dissolved gases, notably oxygen and carbon dioxide. Some of the propertiescompounds ph, sulphates and iron for example of the water may react or precipitate in the sample bottle and result in false results.
There often are severe complications due to the condensers being located at the highest point and subject there to high temperatures, returning the flow in a loop circuit. Depending on the quality of available fresh water supply, waterside problems develop in cooling water systems. Watertreatment and chemical conditioning of open and closed cooling systems. Closedloop cooling water systems operating at c are used for cooling computers, control cabinets, server rooms and various other heatemitting applications. What is a cooling tower water treatment system and how does. Water treatment for cooling towers 1 of 2 water treatment helps ensure that heattransfer surfaces perform to design specifications by amanda meitz, senior microbiologist, nalco diversified technologies, inc. This is done by including hollow conductors in the stator bars. Conductivity of the water has to be restricted in order to limit phasetoground currents. An introduction to cooling tower water treatment cedengineering. Twenty fi ve years ago, it was common to site a new power plant where abundant. Most common tube alloys used in these systems are copper uns c12200 dhp and stainless. Cooling water management intent to minimize the carbonfootprint, water usage and environmental impact of hvac cooling systems and process cooling systems, generally by optimizing the control of water chemistry, and specifically by. This is the key chemistry related problem in stator water cooling 2, and will be discussed in.
To prevent plugging of the hollow conductors, several regimes for stator cooling water chemistry have been established. Municipal or plant water of good quality for domestic use is seldom good enough for boiler feed water. Traditional methods for the evaluation of the quality of. As water treatment professionals, we recognize that no water source is the same and with unique water. Cooling water tower system is a system or an arrangement of technologies in order to keep your cooling tower feed water and circulatory in a good condition, by removing impurities which could cause damage to your cooling water tower system. Electrochemical water treatment for cooling towers nrel.
Cooling tower types cooling towers fall into two main categories. Makeup water water added to the system to replace water lost through evaporation, bleed of and windage recirculation the rate at which water circulates in the cooling tower in m 3 hour litressec bleed off water deliberately bled from the system to prevent the cooling system water from becoming too concentrated. Corrosion control in cooling tower systems water technology. Traditional methods for the evaluation of the quality of this water e. Chemical equilibrium principles of acidsbases, dissolutionprecipitation, oxidationreduction, and complexation applied to understanding the chemistry of surface waters, groundwaters, and. This is a closedloop system, in which the cooling water is sent from the condenser to the cooling tower, where the heat of the water transfers to the ambient air primarily by evaporation. Cooling water systems usually involve low head pumping plants, and often large flow rates, and aim to minimise the power costs for overall plant efficiency. Pitting and crevice corrosion have become much more common.
Yet, failures due to inadequate water treatment and chemistry control, whether they be in the steam generator or cooling system, can cost a. This requires a rapid response, accurate detection and a tailored program to control biological growth. Water chemistry 109 introductory level workshop 1 chapter 7 water chemistry introduction to volunteer water quality monitoring training notebook water chemistry plays an important role in the health, abundance and diversity of the aquatic life that can live in a stream. Best management practice and guidance manual for cooling towers. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. In addition, raw water supplies in south africa are deteriorating due to industrial, urban and rural pollution. When cooling water is not capable to cool down the hot stream to target temperature, chilled water is required.
Treatment and corrosion control of cooling water page 4 section 2 control of corrosion, and chemical attack 2. Oct 26, 2016 a cooling tower water treatment system is an arrangement of technologies that remove damaging impurities from your cooling tower feed water, circulation water, andor blowdown. A 35,000 foot view of a sound water treatment program highlights from last months chemical dosing webinar quick overview of hot water systems the key water treatment problems facing steam supply systems attacking the problems the problems with the condensate piping and its remedies hot water system treatment. Cooling tower water chemistry parameters water treatment. Product contamination may also occur due to leakage of cooling water into the process. Chemistry of iron in natural water survey of ferrousferric chemical equilibria and redox potentials by j. The specific configuration of your system will depend on several things, including.
The cooling water network performance can be changed within a feasible region that is bounded by the maximum reuse supply line and the parallel design. Gases including sulphur dioxide and ammonia, chlorine etc. Changing stator cooling water chemistry abstract large generators employ direct water cooling to remove heat losses in the stator winding. Cooling tower basics evaporation removes about 1,000 btulbof water evaporation rate 1. I recommend a conditioning program unless your water and enviroment as close to heaven. Many of these problems are preventable through proper cooling water chemistry treatment. In order to prevent magnetic particles entering the from. So far, cooling water system and chilled water system are designed separately because the two systems use water with different qualities. What is a cooling tower water treatment system and how. Chemical treatment of water for cooling and heating systems. As the universal solvent, water is capable of dissolving a variety of materials as well as holding.
A common alternative is bromine chemistry, where a chlorine oxidizer and a bromide salt, typically sodium bromide nabr, are blended in a makeup water stream and injected into the cooling water. The chemistry of the water used in cooling water sy stems is extremely complex. Reducing water consumption is a priority for the u. A simple model to help understand water use at power plants. Water chemistry in thermal power plants an overview. In this treatment regime, cuo is formed on the copper. Perform chemical testing on cooling system water to check water.
Possible chemical parameters for changing include oxy gen concentration and ph of the stator cooling water. Pdf water chemistry in thermal power plants an overview. These and other conditions lead to rapid deterioration of the cooling tower, heat exchangers and piping system. When we use water to lower the operating temperature of equipment or entire plants, it is called cooling water.
A comprehensive cooling water treatment program using nonphosphate chemistry and. A chemical capable of killing or inactivating living microorganisms. Excessive amounts of some constituents nutrients, or the lack. The cooling water system may be a once through type or b recirculation type. Industries such as power, pulp and paper, oil and gas, ethanol, steel, mining, leather and manufacturing. In a once through type, the entire water after cooling service, is discharged to the source of intake water. Part 3 will then describe how to use chemistry and ion exchange selectivity to solve certain treatment problems. Some people shy away from trying to understand his subject because they feel its over their heads.
Open recirculating cooling water systems are open to the atmosphere and continuously recycle and reuse the cooling water. Changes in oxygen concentration lowoxygen systems can suffer from increased oxygen concentration in the cooling water system. Stator cooling water is contained in a closed loop system that cools the copper stator bars in water cooled generators. Water and cooling water samples should be analysed as soon as possible, preferably within a week, after sampling. Water vapor evaporates, leaving dissolved or suspended solids in the recirculating cooling water. The draft technical specification says all coolant loops within the system shall have. It will cover the water factors to consider and monitor, proper layup practices, and material selections based on cooling water chemistry and practices. In order to simplify and accelerate the analyses of oil and grease in industrial waters, particularly used in cooling water in heat exchangers, a uvfluorescent sensor sensitive to polycyclic aromatic hydrocarbons pah being part of refined oil products was. If you know your water at the inlet, some characteristics like temperatures ect. Water chemistry is basic but, nonetheless, its still chemistry. Rubik, plymouth tube, usa introduction for the power plant operator, the challenges with cooling water are gre ater than they have ever been. There are less than 100 elements in nature and, by definition, theyre all separate and distinct from one another.
Bibliography of technical papers cooling tower water. Recommended concentration limits to determine allowable. Cooling towers 268 carbon toc concentration of the cooling water, the greater the risk for increased biological fouling. Table 1 below shows typicalguidance values for the cooling water analysis. What type of cooling tower you have open circulating, oncethrough, or closed loop. Jinkuk kim, robin smith, in computer aided chemical engineering, 2002. Chapter 33 pretreatment of cooling water systems chapter 34 air conditioning and refrigeration systems chapter 22 coilend deposition and corrosion control. These solids are present because of makeup water contamination, by internal. Cooling water treatment chemicals inhibitors and microbial. Oilinwater uv fluorescence sensor in cooling tower and other industrial applications. Technical reference for water conservation in cooling towers pub.
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