As boiler water of a given Na:PO ratio is concentrated at local areas of the boiler (under deposits or in zones of film boiling), the sparingly soluble natures of the various phosphate species at boiler water pH values and temperatures cause precipitation (solid phase formation) to occur. The delivery of feedwater to the boiler 12 is controlled by a feedwater pump 19. The method of any of Claims 1 - 18 wherein at least one of said phosphate-feed tracer and said blowdown tracer is a fluorescent tracer and said fluorescent tracer is quantified to provide said phosphate feed rate value and/or said boiler cycles value by a combination of high-pressure liquid chromatography to separate said fluorescent tracer from a fluid matrix and fluorescence analyses of said fluorescent tracer. The line represents the points (combinations of pH values versus phosphate concentrations) at which there exists a 3.0:1 Na:PO mole ratio and only the trisodium phosphate specie is present (the phosphate-pH relationship for trisodium phosphate or 3.0:1 Na:PO line). Non-Phosphorus, Non-Zinc Cooling Treatment, Environmental, Social, & Corporate Governance, Cooling Scale Inhibitors and Deposition Control, Infrequent operator attention and testing, Water softeners are in use, but control is less than ideal, Boiler design, operating pressure, and steam production rates are compatible with precipitating chemistries, High iron levels (>0.5 ppm) in the feedwater, Feedwater hardness greater than ASME guidelines (>1.0 ppm), Exceptional boiler internal cleanliness required. Polymeric dispersants or sludge conditioners are added with the phosphate to condition the sludge for improved removal from the boiler. The present invention provides a pH/phosphate program control method of great sensitivity that is independent of small quality variations in boiler feedwater. The phosphate concentration for purposes of pH/phosphate program control in the process of the present invention is monitored in the feedwater. Look for January February 2018 edition, page 20. http://www.pulp-paperworld.com/emag. Chelants can be very aggressive to boiler metal if fed in the wrong location or overfed. Shown is a Box A (circumscribing Area A) and a Box B, Box B encompassing the combined Area A and Area B. The all-polymer approach, while not applicable to all boiler systems, does have benefits over phosphate and chelant programs when applied correctly. Some of these water tubes may comprise the walls of the furnace in which the heat-generating combustion occurs. A compromise condensate/feedwater pH control range of 8.8 to 9.2 is usually established where both metals are present. Anderson Jos Beber timo artigo! After introduction to the boiler it would not precisely follow the phosphate in the system, and instead it can then act as a blowdown tracer for the boiler-cycles determination purposes of the present invention. Along with that, this program can tolerate larger quantities of solids such as iron (maximum 10 ppb in feedwater) when compared to an AVT All Volatile Treatment (maximum 2 ppb iron in feedwater). (A Na:PO ratio of 2.6 corresponds to a 3:2 blend of trisodium and disodium phosphate.) Corrosion has been occurred only in U-bends sections and the rest of tubes are intact. Generally the linear-emission-response concentration range of a tracer(s) is sufficiently broad to readily estimate the amount of the tracer(s) that will be sufficient for this purpose. I actually did. ORIGINAL CODE: EPIDOS AGRA, Free format text: Given the capability of an inert tracer to function as the phosphate-feed tracer, as a feedwater tracer, and as the blowdown tracer for boiler cycles determination purposes, there would often be no benefit in, or practical reason for, the use of another tracer. Intern, Co-op and Apprenticeship Opportunities, Inability to frequently monitor piping of water system (infrequent shutdown/cleanouts). In any of such instances the monitored stream is not only a part of the blowdown, but also of a generally known rate. Be detectable on a continuous or semicontinuous basis and susceptible to concentration measurements that are accurate, repeatable and capable of being performed on feedwater and blowdown water; 3. Thanks for sharing your knowledge. This method, however, has the a number of limitations. These and other contaminants may enter a boiler in soluble form, and then precipitate in the vicinity of the hot boiler surfaces. All-polymer chemistry can overcome the drawbacks of both phosphate and chelant programs. Natural alkalinity of the feed water will be adequate to keep a high enough level of ph within the boiler. At this specific screen, one can configure the steam generation system. Figure 3 - Operating configuration and control through the controller. For instance, at a temperature of 572 F (300 C) the congruent point is where both the solution phase and the solid phase have an identical Na:PO of 2.85:1. This is actually one of the greatest benefits observed after the use of this controller. Anderson Jos Beber Great article! In preferred embodiment, the phosphate-feed tracer is an inert tracer that is added to the water of the boiler system in an amount at least sufficient to provide a concentration of the inert tracer in the blowdown at steady state of at least about 0.1 ppm. Chelants form soluble compounds with calcium and magnesium during hardness excursions provided there is sufficient free chelant present. Below that boundary, a mixture of tri- and disodium phosphate exists. Film boiling on the water-side metal surface causes an evaporative concentration of salts. Copyright 2022 ChemTreat, Inc. All Rights Reserved. In Equation 10, when water is removed upon evaporation, the equilibrium is forced to the left. There are several water treatment companies which have specific programs that include phosphates for boiler water treatment. A feedwater sidestream 32 is tapped off of the feedwater line 14 and along such feedwater sidestream 32 is a feedwater-monitoring instrumentation 34, discussed below. Phosphate buffers the boiler water, reducing the chance of large pH swings due to the development of caustic concentrations. Here is the link. Be thermally stable and not decompose at the temperature within a boiler; 2. The concentration of the inert tracer added in known proportion to the feedwater, as monitored by the instrumentation 30, will normally fluctuate from the C, The downswing in the tracer concentration to its C. The present invention of course goes farther than just the determination of the cycles value. The actual cycles value is more accurately measured by continuously adding a uniform dosage of an inert tracer to the feedwater and monitoring its concentration in both the feedwater and blowdown, along the feedwater line and blowdown line respectively, and substituting the concentrations determined into Formula I. Removal of silica and/or alkalinity from the makeup water. Most products contain a blend of two polymers, allowing us to incorporate the best polymer functionalities into a specific product. Nonetheless, preferably a calibration curve over the linear-emission-response concentration range would be prepared or obtained before employing a given tracer(s), and preferably the tracer(s) would be added to the feedwater of the boiler system in an amount sufficient to provide a concentration of the tracer(s) in the feedwater and/or boiler that is within the linear-emission-response concentration range. Figure 2 is a visualization of many screens available on the controller. Another group of inert fluorescent tracers that are preferred for use in the process of the present invention, particularly under pressures of no more than about 1,000 psi, are the various sulfonated derivatives of pyrene, such as 1,3,6,8-pyrene tetrasulfonic acid, and the various water-soluble salts of such sulfonated pyrene derivatives. (1) The maximum solids concentration within the boiler at any given time is set for an equivalent of 10 mg solids per liter of boiler water; (2) The feedwater has an average solids concentration of 1 mg/liter, is fed to the boiler at a rate of 1,000,000 lb/day and thus 1 lb. A1, Designated state(s): The TRI-AD pH/phosphate program operates above the 3.0:1 Na:PO line (Figure 3); the Congruent Control pH/phosphate program operates below the 3.0:1 line, which is referred to in the technical field as the "captive alkalinity" zone. STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT, Free format text: Natural alkalinity of the feed water will be adequate to keep a high enough level of ph within the boiler. There is no substitute for deep, industry-specific expertise when it comes to addressing the unique challenges you face in your business. Hydroxyapetite is softer than other deposits and will remain in suspension as long as it is kept in circulation. Polymers sequester hardness, forming soluble compounds. I think overflow of water into the tubes of superheater section and following evaporation could create an acidic local area and end in acid phosphate corrosion. When there is or may be a specific chemical specie of reasonably high fluorescence in the background, the tracer(s) and/or the excitation and/or emission wavelengths often can be selected to nullify or at least minimize any interference of the tracer measurement(s) caused by the presence of such specie. of solids must be discharged per day (see 2 above) and thus the blowdown rate must be 100,000/lb per day; and. The present process also overcomes problems with phosphate "hideout", which causes operators to make incorrect program adjustments in their efforts to stay within their control parameter range. Sensing a characteristic of the tracer in the feedwater downstream of its addition point that is equivalent to its concentration in the feedwater; 3. Porous, insulating-types of deposits allow boiler water to diffuse into the deposit where the water becomes trapped and boils. 69402138, Country of ref document: Figure 3 also shows the specific phosphate - pH coordinate boundaries based on boiler drum pressure. At tracer concentrations higher than a given tracer(s)'s linear-emission-response concentration range, there is a negative deviation from ideal (linear) behavior, the degree of emission for a given concentration being less than predicted by a linear extrapolation. Unfortunately, conventional congruent control did not take into account the interaction of phosphate compounds with deposits and corrosion products,. In preferred embodiment, at least one of the phosphate-feed tracer and the blowdown tracer is a component of a formulated phosphate product. The inert tracer may be used for other purposes, such as the determination of percent holding time (half-life time), as a reference standard in the monitoring of concentration of water-treatment agent concentration level, and the like, concomitantly with the cycles determination. Such dispersants include without limitation polyacrylic acid, polymethacrylic acid, acrylic acid/acrylamide copolymers, polyisopropenyl phosphonic acid and the water-soluble salts of such polymeric species, and these and other boiler additives are conveniently injected into the feedwater of a boiler system together with phosphate as a formulated treatment product. Thus, one mole of trisodium phosphate will increase boiler water pH equivalent to the addition of one mole sodium hydroxide. The more pure the feedwater, the greater the percentage variance range and thus the more difficult it becomes to make accurate boiler cycle measurements from normal feedwater impurities. Iron compounds form porous, insulating-types of deposits that are particularly active in promoting surface-concentration of boiler chemicals.
Most Comfortable Guitar Strap, 48 Inch Bar Clamp Home Depot, Arm Sleeves Cover Uv Sun Protection, Weathertech Mats Hyundai Santa Fe, Whitewash Brick Before And After, Home Depot Computer Desk With Keyboard Tray, How To Travel Around Europe With Luggage, Ibis Leiden Centre Email Address, Fender Hammertone Pedals Release Date,
