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      The diversification of water treatment options

      As long as it is steam cycle power production industry leading, water treatment technology choice to the power plant success operation it is crucial, ensure the safe operation of the boiler and steam turbine power plant management personnel required strict control such as corrosion, fouling, corrupt plugging, deposition of salts, etc.

      But there exist some difficult due to the requirements, both to design a excellent water treatment scheme is more difficult than before. Management department of chemical limited selection and require lower emissions from wastewater; Environmental protection personnel to water consumption to ease; Raw water point, in addition to the water quality deterioration, power department directors and shareholders for their own interests also require lower running costs.

      The comforting thing is, can use new technology to deal with these challenges, for example:

      · RO (RO) and EDI (electricity to ion method) make the boiler make-up water treatment reduces the chemical storage and processing.

      · add oxygen treatment the boiler no sewage can prevent the erosion and deposition of salts.

      The outage protection technology, improve the flexibility of increased operation, and reduce the corrosion.

      Because the agency personnel and all the water treatment professionals offer to make all these advanced technologies are more likely to win. Agency staff tried to make the task even autonomy for those in key positions and delivery on (at least in theory) personnel to optimize the design of water treatment scheme -- because these companies have professional talents and resources.

      Need explanation is, although agency personnel to keep some plants for a long short-term tracking service records, but power plant managers still don't believe these benefits. Similarly, most inspectors still wandering in these in water treatment field outside of the emerging senior technology.

      No matter what kind of level by an enterprise provide the agency personnel or what kind of technology, it is very clear: a successful water treatment technology as before to need to every detail should give sufficient attention.

      Reduce the use of chemical reclamation potions

      In the past ten years, electricity to ion method (EDI) is industrial water treatment technology in one of the two most significant progress, reason is: power plant now because of the use of chemical pue water not renewable elixir caused the cost, space, safety and environmental problems.

      EDI commercial operation actually has ten years' history, but according to Glegg water processing company founder and CEO Robert K Glegg relation, the system can only in early the situation of low flow run, but also exists reliability problems. Now already can adapt the EDI systems all kinds of water flow and power requirements of purity, its reliable operation, this is largely because EDI and water treatment field another important technique -- reverse osmosis (RO) already unifies in together.

      In RO and EDI is application of boiler make-up water before traditional production technology for chemical way regeneration of ion exchange device. After the pretreatment, using force to pump water supply by several stages of the desalination (usually is Yang bed, Yin bed and mixed bed) in this several stages of, impurities away by ion exchange process is.

      Because resin bed must frequently regeneration, therefore need to acid, alkali etc for storage, chemical regeneration process.

      To the early 1980's, reduce use chemicals idea led to RO industrial application. The operation in RO process, through the supply water pressure make its overcome separated by a semipermeable membrane of two

      Different concentrations of osmotic pressure, produced solution when applied reverse pressure, water will be enough to move in the opposite direction from the more diluted concentration is one side of high concentration on one side flow, thus produce pure water and water side FeiYan in thick liquid left.

      In order to achieve water quality requirements, boiler make-up of RO effluent must further except salt, to the 1980s, through the mixed bed ion exchange device completed this process, no matter how this process reduced consumption of chemical reclamation potions. With the new ion exchange process such as countercurrent regeneration, a room full of bed, special resins development, make the operation cost and the use of chemicals that have been further to reduce, meanwhile RO/mixed bed combination system also has been widely used.

      Continuous regeneration

      Recently, through application EDI systems to replace the traditional ion exchange device, make some power plants and a step forward. Glegg explanation says the new technology also USES mixed bed ion exchange resin, but there is a key difference: it will resin combination with ion-exchange membrane, not the use of chemicals but use a dc field to constantly regenerative resin.

      In EDI film pile in the freshwater chamber, the blender anions and cation exchange resin clip in anion and cation exchange membrane between. Dc voltage make water hydrogen ions and hydroxyl ions through the resin from freshwater room to move in the direction of the corresponding film, when these ions through exchange membrane, hydrogen ions and hydroxyl ions to combine into the water. This kind of hydrogen ions and hydroxyl ions produced and migration is achieved continuous regenerative resin mechanism.

      When the sodium and chloride into the impurities such as ion suck them to the corresponding ion exchange resin, these impurity ions will happen ordinary ion exchange reaction, and correspondingly replacement out of hydrogen ions and hydroxyl ions.

      Once inside the ion exchange resin impurity ions have joined the hydrogen ions and hydroxyl ions moved to exchange membrane direction, these ion will be continuously through resin through exchange membrane into until the high salinity water room.

      These impurity ions every room exchange membrane due to the adjacent to the corresponding action can't blocked further migration of electrode direction, so the impurity ions to focus to strong water chamber, then can the impurity ions thick containing no-flow periods of the film. The current application EDI film pile can produce resistivity, more than 16MW cm (0.063 ms/cm) the pure water.

      The biggest advantage is that no USES EDI principally regeneration, chemicals and don't need chemical regeneration elixir storage tank and the corresponding neutralization pool, and not be harmful chemical wastewater through collection, storage and processing.

      Another advantage is that EDI emissions liquid (water) usually thicker than water quality pretreatment system, it is better to exhaust emissions from liquid can be directly, so the entrance to the RO eliminated effectively wastewater discharge. Instead, the regeneration of the mixed bed is a one-time process, because use chemicals, its waste liquid bed regenerative resin contained in high salinity water than general EDI 3-4 times the abandoned ions.

      According to Glegg water processing company reports, recent module type EDI technology in its flow rate of 8000l/min still has good economy, its output can decrease the way of the film by simply adjust. The current EDI device in the economy with ion exchange bed can be comparable, simplified membrane composition and reduce the number of new technology such as membrane its expense ratio of the early technology have greater save, EDI operational costs of the mixed bed quite, and the consumption and mixed bed regenerative elixir expenses are roughly equal.

      Currently the world there are many different water treatment equipment suppliers can provide RO/EDI systems, for example Glegg in North America, Europe and Asia through more than 60 home water treatment company to sell its E - Cell system. E - two of the engineering application Cell recently 1100MW Coryton of Britain's power and thermal Takoradi of Ghana in west Africa Volta River project by the place possesses Takoradi power plant is the only one of Ghana, built in its thermal before all the country's electricity actually comes from the hydropower station on the lake Volta.

      Robert Glegg believe in three to five years' time, 85% of industrial water treatment system will adopt RO/EDI systems, he expects the remaining 15% is used in part of the higher cost of pretreatment of couldn't counteract the chemical method or the RO/EDI systems the inherent benefit brought by the occasion.

      Add oxygen treatment

      For water treatment of once-through boiler water demand is higher, because all into steam, so in the system doesn't allow impurity, so many applied to existing drum boiler phosphate processing technology does not apply to dc boiler.

      More importantly, in once-through boiler himwith impact corrosion (FAC) the knotty problems, FAC can make the carbon steel pipe thinning, till its leak or rupture. When that happens, the conventional carbon FAC four oxidation SanTie cover dissolved in high-speed flow or wet steam, this whole process makes oxidation layer to reduce or be removed, and soon spread to the inner metal, FAC make wall thinned speed can reach 3mm/year.

      A nuclear power plant in 1986 the pipeline rupture accident happening, henceforth together already began to prevent nuclear power, but the FAC happened recently appeared together causing casualties of the pipes burst accident, people have begun to pay close attention to all the once-through boiler.

      Over the years, many countries in the power plant boiler adopts full volatile processing (AVT), in this process, ammonia (usually ammonia to join to the water,) to keep the PH between in 9.0-9.5; Will the deoxidant (usually hydrazine) added to give water, make oxygen levels in the following. 5ppb maintain

      Although AVT can effectively reduce can be steam carry impurities, but it can't prevent for condenser leakage and make salts material leak into the system, so within AVT need to fine treatment of condensate water and content of impurities close monitoring. There is little need to point out is, studies have shown that under hypoxic environments, such as AVT process most destructive power, FAC.

      Now, a type called add oxygen treatment (OT) technology has in once-through boiler AVT process, replace the technology into OT 1960s not period was first development and application in Germany, and during the next twenty years to Europe and Japan. At present the craft has the former Soviet union and the United States for nearly 200 units of more than 100 plants use.

      The basis of OT in pure water contains 50-200ppb dissolved oxygen, low carbon steel surface will produce corrosion function. To do not contain copper system study, will hydrogen peroxide or oxygen to join condensation water, to keep to the oxygen content is 200ppb, this method still need to control water content of impurities, in order to make its electrical conductivity to 0.15 ms/cm (note: should be 0.15 muon s/cm) the following; The system contains copper alloy, oxygen levels in the water should be reduced to 50ppb, the electric conductivity can be allowed to 0.2 ms/floating cm (note: should be 0.2 muon s/cm).

      The main purpose of OT economizer entrance is to reduce the iron 2ppb or lower, at this point, the world has been compared with examples show that AVT process, economizer entrance iron at least by 90%.

      Note: convert OT will reduce caused by damage to FAC since the sensitivity of the manufacturer, but also need to take additional measures, relevant factors include pipes in the content, the chrome temperature and water system, such as the likely velocity to inspect and modification of these parameters.

      In addition also need to inspect pipe system to determine the role by previous FAC weakened part, two kinds of non-destructive testing method of ultrasonic affected X-ray scan method, it has been successfully used for measuring pipeline, including existing wall thickness measurement result more accurate ultrasonic some. The Palo Alto Calif American electric power research institute (EPIR) is working on two new non-destructive technique evaluation, this technology need not isolate, thus greatly saves time and manpower.

      The first technology is the Netherlands development pulsed eddy current technology, it has two power plants in the United States -- Public Service Co of Colorado 's Hayden and Public Service Co of New Mexico' s San Juan and Iberdola SA of Spain which Bitbao supports two power plants in the Santurce -- Cofrentes and test run well.

      The second technology is guided wave technology in check, it long pipe in very useful, and technology to be used for pulsed eddy current collected a lot of wall thickness data. Guided wave technology has two factories in the United States -- San Antonio City Public Service Board 's JT Deely and WB Tuttle conducted on-site testing. EPRI reported that TR - 108449 and TR - 108859 can provide more detailed information.

      New technology. Stop protect

      When the unit power is running, boiler and water treatment technology such as EDI new chemistry and the system reduced OT the deposited salt and corrosion speed, but when unit shipments, these plants will meet again serious corrosion problems.

      Because do not regular downtime, as with the dozen circle or in a hot standby mode the increase in the number of units, this problem become more apparent. Incorrect disable protection method can produce many problems, especially will make the copper tube condenser, cracks within happened in, turbine phenomenon such as copper deposition. Whatever - units is the rated flow or lower flow dozen circulation, the improved method can reduce the discontinued protection operational and maintenance costs and improve the operation reliability of power units.

      If the length of time a longer (such as a month), of the entire unit must be wet or dry, protection treatment discontinuation of the length of time and crew stop the design characteristics affect discontinuation of protection plan options, such as the power plant in general, the main steam pipe is not designed for carrying water, so for these lines, wet disable protection technology is not feasible.

      Dry discontinuation of units in the system to protect treatment means that removes all the liquid outside should have removed and inert gas replacement (usually with nitrogen), will be drained in the system, after inject nitrogen in before, must use desiccant to remove residual vapour. Once the filling the nitrogen, system must seal to reduce nitrogen gas leakage and prevent other pollutant leakage.

      If not in the system for sealing of words, experts suggest now consider using a medium (such as filtered dry air) constantly wet condition for ventilation or convert discontinued processing (will be discussed below). What is worth mentioning, although nitrogen is non-toxic, but it replace oxygen can make people suffocation, an American power plant once for nitrogen through the steam system to leak into the room, make a turbine is the technical personnel working in the engine room suffocated to death.

      AddTime:2011/4/8 19:05:31 Hits:5273 [Back]
       
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      亚洲同志GV钙片在线观看
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