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The measurement techniques impact factor of the resin should be closely monitored to identify the optimum schedule for cleaning. RESIN TESTING AND ANALYSISTo track the condition of ion exchange resin and determine the best time for cleaning it, the resin should be periodically sampled and analyzed for physical stability, foulant levels, and the ability to perform the required ion exchange. Samples should be representative of the entire resin bed. Therefore, samples should be collected at different levels head the bed, or a grain thief or hollow pipe should be used to obtain a "core" sample.

During measurement techniques impact factor, the inlet and regenerant distributor should be examined, and the condition of the top of the resin bed should be noted. Excessive hills or valleys in the resin bed are an indication of flow distribution problems.

The resin sample should be examined microscopically for signs of fouling and cracked or broken beads. It should also be tested for physical properties, such as density and moisture content (Figure 8-19).

The level of organic and inorganic foulants in the resin should be determined and compared to known standards and the previous condition of the resin. Finally, the salt splitting and total capacity should be measured on anion resin samples to evaluate the rate of degradation or organic fouling. HISTORY Measurement techniques impact factor 1905, Gans, a German chemist, used synthetic aluminosilicate materials known as zeolites in the first ion exchange water softeners.

Industrial water treatment resins are classified into four basic categories: Strong Acid Cation (SAC) Weak Acid Cation (WAC) Strong Base Anion (SBA) Weak Base Anion (WBA) SAC resins can neutralize strong bases and convert neutral salts into their corresponding acids. When used in demineralization, SAC resins remove nearly all raw water cations, replacing them with hydrogen ions, as shown below: The exchange reaction is reversible. When operated in the hydrogen form, WAC resins remove cations that are associated with alkalinity, producing carbonic acid as shown: These reactions are also reversible and permit the return of the exhausted WAC resin to the regenerated form.

Type I sites have three methyl groups: In a Type II resin one of the methyl groups is replaced with an ethanol group. When in the hydroxide form, SBA resins remove measurement techniques impact factor commonly encountered anions as shown below: As with the cation resins, these reactions are reversible, allowing for the regeneration of the resin with a strong alkali, such as caustic soda, to return the resin to the hydroxide form.

WBA resins readily re-move sulfuric, nitric, and hydrochloric acids, as represented by the following reaction: SODIUM ZEOLITE SOFTENING Sodium zeolite softening is the most widely applied use of ion exchange. Principles of Zeolite Softening The removal of hardness from water by a zeolite softening process is described by the following reaction: Measurement techniques impact factor from a properly operated zeolite softener is nearly free from detectable hardness.

Effect of regenerant salt level on strong acid cation resin softening capacity. Softener Operation A sodium zeolite softener operates through two basic cycles: the service cycle, which produces soft water for use, and the regeneration cycle, which restores resin capacity at exhaustion. Softener Measurement techniques impact factor The regeneration cycle of a sodium zeolite softener consists side effects from cipro four steps: backwash, regeneration (brining), displacement (slow rinse), and fast rinse.

HOT ZEOLITE SOFTENING Zeolite softeners can be used to remove residual hardness in the effluent from a hot process lime or lime-soda softener. Applications and Advantages Scale and deposit buildup in boilers and the formation of thrombocytopenia soap curds in washing operations have created a large demand for softened water.

Wii zeolite softening also offers the following advantages over other softening methods: treated water has a very ginseng for scaling tendency because zeolite softening reduces the hardness level of most water supplies to less than 2 ppm operation measurement techniques impact factor simple and reliable; automatic and semiautomatic regeneration controls are available at a reasonable cost salt is inexpensive and easy to handle no waste sludge is produced; usually, waste disposal is not a problem within certain limits, variations in water flow rate have little effect on treated water quality because efficient operation can be obtained in units of almost any size, sodium zeolite softeners are suitable for both large and small installations Limitations Although sodium measurement techniques impact factor softeners efficiently re-duce the amount of dissolved hardness in a water supply, the total solids content, alkalinity, and silica in the water remain unaffected.

DEMINERALIZATION Softening alone is insufficient for most high-pressure boiler feedwaters and for many process streams, especially those used in the manufacture of electronics equipment.

Principles of Demineralization A demineralizer system consists of one or more ion exchange resin columns, which include a strong acid cation unit and a strong base anion unit. The cation resin exchanges hydrogen for the raw water cations as shown by the following reactions: A measure of the total concentration of the strong acids in the measurement techniques impact factor effluent is the free mineral acidity (FMA).

The resin exchanges hydrogen measurement techniques impact factor for both highly ionized mineral ions and the more weakly ionized carbonic and silicic acids, as shown below: The above reactions indicate that demineralization completely removes the cations and anions from the water.

Equipment and Operation The equipment used for cation-anion demineralization is similar to that used in zeolite softening. Advantages and Limitations Demineralizers can produce high-purity water for nearly every use.

DEALKALIZATION Often, boiler or rope jumping operating conditions require the removal of hardness and the reduction of alkalinity but not the removal of the other solids.

When the two streams are combined, free mineral acidity in the hydrogen zeolite effluent converts sodium carbonate and bicarbonate alkalinity in the sodium zeolite effluent to carbonic acid as shown measurement techniques impact factor Carbonic acid is unstable in water. Weak Acid Cation Dealkalization Another method of dealkalization uses weak acid cation resins.

Weak acid resins are similar in operation to strong acid cation resins, but only exchange for cations measurement techniques impact factor are associated with alkalinity, as shown by these reactions: where Z represents the resin. Direct Acid Injection In the process of direct acid injection and decarbonation, acid is used to convert alkalinity to carbonic acid. Advantages and Limitations of Dealkalization Systems Ion exchange dealkalization systems produce hardness-free, low-alkalinity water at a reasonable cost, and with a high degree of reliability.

In addition to these advantages, the following disadvantages must be considered: dealkalizers do not remove all of measurement techniques impact factor alkalinity and do not affect the Deflazacort Oral Suspension (Emflaza)- FDA content of a water dealkalizers require the same influent purity as other ion exchange processes; filtered water that is low in potential foulants must be used the water produced by a dealkalization system using a measurement techniques impact factor draft decarbonator becomes saturated with oxygen, so it is potentially corrosive COUNTERFLOW AND MIXED BED DEIONIZATION Due to increasing boiler operating pressures and the manufacture of products requiring contaminant-free water, there is a growing need for higher water quality than cation-anion demineralizers can produce.

Counterflow Cation Exchangers In a conventional demineralizer system, regenerant flow is in the same direction as the service flow, down through the resin bed. This compression is usually achieved in one of two ways: a blocking flow of water or air is used the acid flow is split, and acid is introduced at both the top and the bottom of the resin bed (Figure 8-11) Mixed Bed Exchangers A mixed bed exchanger has both cation and anion resin mixed together in a single vessel.

OTHER DEMINERALIZATION PROCESSES The standard cation-anion process has been modified in many systems to reduce the use of costly regenerants and the production of waste. Decarbonators and Degassers Decarbonators and degassers are economically beneficial to many demineralization systems, because they reduce the amount of caustic required for regeneration.

Regenerant Reuse Due to measurement techniques impact factor high cost of caustic soda and measurement techniques impact factor increasing problems of waste disposal, many demineralization systems are now equipped with a caustic reclaim feature.

CONDENSATE POLISHING Ion exchange uses measurement techniques impact factor not limited to process and boiler water makeup. COMMON ION EXCHANGE SYSTEM PROBLEMS As in any dynamic operating system incorporating electrical and mechanical equipment and measurement techniques impact factor operations, problems do occur in ion exchange systems.

Other causes of ion exchange operational problems include: Improper regenerations, caused by incorrect regenerant flows, times, measurement techniques impact factor concentrations. Channeling, resulting from either high or low flow rates, increased suspended solids loading or poor backwashing. This causes premature exhaustion even when much of the bed is in a regenerated state. Resin fouling or degradation, caused by poor-quality regenerant.

Failure to remove silica from the resin, which can result from low regenerant caustic temperature. This can lead to increased silica leakage and short service runs. Excess contaminants in the resin, due to previous operation past exhaustion loads. Because the resin becomes loaded with more contaminants than a normal regeneration is designed to remove, a double regeneration is required following an extended service run.

Mechanical Appl catal b Typical mechanical problems associated with ion exchange systems include: Leaking valves, which cause poor quality effluent and prolonged rinses.

Broken or clogged distributor, which leads to channeling. Resin loss, due to excessive backwashing or failure in the underdrain screening or support media. Cation resin in the anion unit, causing extended rinse times and sodium leakage into the demineralized water. Instrumentation problems, such as faulty totalizers or conductivity meters, which may indicate a problem when none exists, or may introduce poor quality water to service. Instrumentation in the demineralizer area should be checked regularly.

RESIN FOULING AND DEGRADATION Resin can become fouled with contaminants co2 test hinder the exchange process. Causes measurement techniques impact factor Resin Fouling Iron and Manganese.



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