Deionization system, continuous

With each pass through the system, some water is vaporized, so that some makeup water is necessary. The amount of water evaporated can be determined by running an energy balance. As water is added the concentration of minerals and other substances in the water increases, since they are not removed by evaporation and every pound of makeup water adds some more. To counteract this build-up, some water must be continuously removed from the system. This is known as blowdown. As a rule of thumb, the blowdown is about 0.3% of the water being recirculated for each 10°F (5°C) of cooling that occurs within the tower. This assumes a solids concentration in the water of 4-5 times that in the makeup water. In places where water is scarce and hard, a deionization system may need to be installed.13... 

Fearful that they may lose their reputation in the community, WAA requested a government audit of their operations to see if the problem could be internal. Indeed, the auditor concluded that the problem was likely due to a contaminated distilled water supply. It turns out that WAA had previously been using a conductivity meter to continuously monitor the quality of the water as it elutes from the distiller and had taken it offline some time earlier because it was apparently malfunctioning. Besides always indicating that the water was highly conductive despite the use of an expensive distillation and deionizing system, it also seemed to be the source of unusual colorations and odors found in the water. As soon as it was taken offline, the colorations and odors ceased. 

A major effort was initiated to deionize all three reactor basins on a continuous basis using portable deionizing systems, which had been in use since the mid-1960s. This effort resulted in some improvements in all three basins, but because of the hmited number and availabihty of portable deionizers for the three basins, the improvements were slow, and new mixed bed deionizers were acquired for the K and L basins. 

Process Water Purification Boiler feed water is a major process apphcation of RO. Sealants and colloids are particularly well rejected by membranes, and TDS is reduced to a level that makes ion exchange or continuous deionization for the residual ions very economic. Even the extremely high quahty water required for nuclear power plants can be made from seawater. The iiltra-high quahty water required for production of electronic microcircuits is usually processed starting with two RO systems operating in series, followeci by many other steps. 

AVT Barg BD BDHR BF BOF BOOM BOP BS W BSI BTA Btu/lb BW BWR BX CA CANDUR CDI CFH CFR CHA CHF CHZ Cl CIP CMC CMC CMC COC All-Volatile treatment bar (pressure), gravity blowdown blowdown and heat recovery system blast furnace basic oxygen furnace boiler build, own, operate, maintain balance of plant basic sediment and water British Standards Institution benzotriazole British thermal unit(s) per pound boiler water boiling water reactor base-exchange water softener cellulose acetate Canadian deuterium reactor continuous deionization critical heat flux Code of Federal Regulations cyclohexylamine critical heat-flux carbohydrazide cast iron boiler clean-in-place carboxymethylcellulose (sodium) carboxy-methylcellulose critical miscelle concentration cycle of concentration... 

Bubble Point Constancy. Although the exact relationship between the bubble point and the "pore size" of a microfiltration membrane is a matter of dispute (11, 12, 13, 14), nevertheless, it remains the quickest and most convenient means for demonstrating the continuing integrity of a membrane filtration system. It is consequently important that the bubble point be both reproducible (within a given range) and constant. It was, therefore, of considerable interest to discover that the bubble points of both conventional and poly(vinylidene fluoride) membranes increased with immersion time in deionized water whereas those of Tyrann-M/E and polyamide remained essentially constant (Figure 6). 

The efficiency of these steps can be conveniently monitored by continuous in-line measurement of the resistivity of the water (deionization results in increased resistivity, typically to levels of 1-10 MQ). If the resistivity of the deionized water falls below a value of approximately 1 MQ, automatic system shut-off, followed by regeneration of the anion and cation exchange beds (with NaOH and HCl respectively), is initiated. 

Continuous electrodeionization is primarily used as an alternative to ion exchange. Because of the extensive pretreatment required by CEDI systems, the technology has grown into a polisher for RO (see Figure 16.18). Continuous deionization can achieve mixed-bed water quality of RO permeate without the need to store and... 

The NO2 exposure was a short-term experiment where the panels were exposed to a mixture of 649 ppb NO2 in air. The total exposure time was 25 h. The microprocessor-controlled chiller system was used to generate two 7-h periods where the panels were covered with dew. The two wet periods were separated by a 5-h dry period. NOx concentrations were monitored continuously. At the end of the experiment, the panels were sprayed with either 50 mL of deionized H2O or NH4HSO4 solution (pH=3.5). The volume of collected dew was determined. The dew was then analyzed for N02, NO3", S03 , and S04" by ion chromatography and for Zn by atomic absorption spectroscopy. The rain rinse was analyzed in a similar way. 

The single-wafer puddle process, operating in an automatic continuous mode in a track system, is now the most commonly used method for resist development. It involves an initial dispense of the developer on each wafer, forming a puddle that covers the entire wafer surface for a period of time on the order of 30-75 seconds, following which the developer is rinsed off with deionized water. Additional... 

The equipment required for water treatment will be determined by the quality of the incoming water. Typically, a USP pharmaceutical grade system will require pretreatment (filters), deionization, reverse osmosis, and potentially a polishing step such as continuous deionization. Many systems now incorporate UV filters for sanitization, which kill micro-bials and also eliminate ozone. 

In equipment similar to that used in Procedure 5-3 with provisions for maintaining a nitrogen atmosphere in the system, 210.75 gm of deionized water, 0.75 gm of Tergitol-7 (sodium heptadecyl sulfate, an anionic surfactant from Union Carbide), 12.5 gm of Cellosize WP-09 (a protective colloid from Union Carbide) and 1 gm of potassium persulfate is blended under nitrogen with agitation. Then 25 gm of vinyl acetate is added and the mixture is heated to 70°C. When the polymerization has started, with stirring, over a 2- to 3-hr period, 250 gm of vinyl acetate is added. The temperature is maintained at 70°-80°C. After the addition has been completed, heating at 70°-80°C is continued for an additional 30 min. The residual monomer content of this latex is less than l . ... 

A variety of ion exchange resins with strong and weak acid, weak base, and quaternary ammonium ion functionality are available in bead form well suited for filtration from reaction mixtures and for use in continuous flow processes. They have been used for >30 years in flow systems for water deionization. Sulfonic acid resins are already used on a large scale as catalysts for the addition of methanol to isobutylene to form methyl terr-butyl ether, for the hydration of propene to isopropyl alcohol, and for a variety of smaller scale processes. Tertiary amine resins have been used as catalysts for the addition of alcohols to isocyanates to form urethanes. The quaternary ammonium ion resins could be used as reagents with any of a large number of counter ions, and as catalysts in two and three phase reaction mixtures, although the author is not aware of any commercial process of this sort at present. 

A microemulsion polymerization method [62,63] was also reported to produce magnetic polypyrrole nanocomposites filled with 7-Fc203. The nanoparticles were dispersed in the oil phase. FeCla was used as an oxidizing agent. Sodium dodecylbenzenesulfonic acid (SDBA) and butanol were used as the surfactant and cosurfactant, respectively. FeCl3 (0.97 g) was dissolved in a mixture of 15 mol deionized water, SDBA (6 g), and butanol (1.6 ml). A specific amount of 7-Fc203 suspended nanoparticle solution was added to the above solution for dispersion. Pyrrole was added for nanocomposite polymer fabrication in the microemulsion system. The polymerization was continued for 24 hours and quenched by acetone. 

Radionuclide activity in the basin water. Radionuclide activity in the basin water (leached from the spent fuel) should be monitored and controlled to levels deemed to be safe for personnel working in the surrounding area. Continuous deionization of the water removes a and p-y radioactivity from the water. Fission products such as Cs and other radionuclides may be found in the water where failed spent fuel elements or cladding breached fuels are stored. Spedal materials such as zeolite can be used in ion exchange type purification systems to specifically remove these radionuclides. 

In a three-necked flask equipped with a mechanical stirrer, the tetraamine and solvent PPA were added. The solution was stirred at 110°C under nitrogen atmosphere for about 1.5 h to get a homogeneous solution. An equimolar amount of diacid was added to the solution, and the reaction was continued for 12h at 140 °C. Then a catalytic amount of phosphorus pentoxide and triphenyl phosphite (TPP) were added into the system. The solution became brownish and viscous. It was heated to about 230 °C for another 24 h and then poured into the water, washed with deionized water several times, and neutralized by alkaline solution. Finally, the polymer was dried under vacuum for 24h [15,16]. 

Reaction Conditions in Continuous Flow Reactor. For the thermal reactions, 1.2 gm cysteine and 1.5 gm ribose were combined in 100 mL of deionized water (pH= 3.75). This system was pumped through a 1.0 mL sample loop made of 1/16 inch... 

Peanut Oil/Cysteine and Peanut Oil/Methionine Systems. Peanut oil (100 g) and 10.0 g of cysteine or methionine were mixed and placed in a 500-mL two-neck round-bottom flask, which was interfaced to a simultaneous purging and solvent extraction (SPE) apparatus developed by Umano and Shibamoto 13). The mixture was heated at 200 C for 5 hr while stirring. The headspace volatiles were purged into 250 mL of deionized water by a purified nitrogen stream at a flow rate of 10 mL/min. The volatiles trapped by the water were continuously extracted with dichloromethane (50 mL) for 6 hr. The water temperature was kept at 10°C by a Brinkman RM6 constant-temperature water circulator. The dichloromethane extract was dried over anhydrous sodium sulfate, and the extract was then concentrated to 2.0 mL by fractional distillation with a Vigreux colunm at atmospheric pressure. The concentrated extract was placed in a vial and stored under argon at -4 C until tested for antioxidative activity. 

Two operations in-the Purification Area of Building 105-K are continuing in order to place deionizer resins and moderator in storage. In the first process, moderator is displaced fi-om deionizer resin and evaporated in the dedeuterization system. In the second process, dnimmed moderator is evaporated in the distillation evaporator which Is part of the high activity moderator (HAM) system. Both of these systems are used to remove fission products and other impurities from the mod tor. 

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