Silica In Boiler Feed Water

Pans of quick lime or silica gel should be put into the boiler and it should then be closed up. General example of power generation. Figure 5: ABMA Boiler Quality. Corrosion products were being transported from upstream. Silica and Boiler Feed Water Silica is a problem for high pressure boilers. in the boiler feedwater while Exit denotes concentrations in the liquid phase at one particular steam pass exit. Silica is a boiler-water contaminant that will deposit in the ST and adversely impact its performance if allowed to carry over in the steam. The higher blow down rates were significantly affecting the refinery's water, chemical, and natural gas costs. Silica (sand) if present in water can form exceedingly hard scale. But what is a boiler feed water treatment system and how does it work?. In boilers where high vaporisation occurs, the superheated surface film may become salt-saturated with lower salinity in the blowdown. Industrial Wastewater Reuse Technologies SAWEA Boiler feed water Silica Removal for Boiler Feed Water. Problems facing industry customers. Silica is not listed in the Primary or the Secondary Drinking Water Standards issued by the US EPA. Boiler feedwater is usually a combination of returned condensate plus pre-treated makeup water from a softener, reverse osmosis, or other purification system. Boiler Feed Water and Boiler Water - EWT Water. Chemical cleaning is essential to the chemistry control program as it improves boiler chemistry stability by safely removing all deposits from inside boiler tubes (including organics from. Make-up water is usually filtered and treated before use. Impurities enter this boiler water from the boiler drum and from vaporous carryover, which deposits on the turbine and causes erosion damage. Common feedwater contaminants that can form boiler deposits include calcium, magnesium, iron, copper, aluminum, silica, and (to a lesser extent) silt and oil. of boiler volume) may be placed on trays inside the drums to. can be tolerated. With the minimum maintenance, the DELTA-20DP also ensures that Covanta Energy PASCO has a continuous supply of clean, low TDS feedwater to its boiler units. It is generally agreed that where possible on steam boilers, the principal feedwater treatment should be external to the boiler. Contains a scale inhibitor, which minimizes the scale formation. It provides a place for the introduction of water treatment chemicals into the boiler. Impurity in Steam Affect: - High silica in steam - Phosphate carry over - High level of water in drum Affect: - Solids carry over in steam will lead to deposits on turbine blades, increase of first stage pressure and increase of axial shift of turbine rotor Corrective Action: - Monitor boiler water chemistry and operate CBD as per chemist's. Dissolved solids such as calcium, magnesium, iron, and silica in feedwater can quickly damage a boiler beyond repair. Steam and water analysis system (SWAS) is a system that is used to analyze and display critical information about steam or water in the power cycle. Solution Technological advances in membrane filtration systems create an opportunity for industrial boilers and steam power plants to treat boiler feed water streams to meet stricter system performance. Chemical treatment coupled with 3D TRASAR technology provides comprehensive boiler water treatment solution mitigating scale and corrosion of the boiler system. Phosphate/sulfite alone failed to transport Ca, Mg, or Fe metal ions through the boiler. This allows the analyser to determine the purity of boiler feed water and steam, and to provide early warnings of condenser leaks or exhaustion of ion. When the phosphate requirement was calculated, there was a mismatch. of boiler volume) may be placed on trays inside the drums to. The advantages of carbon filters are (1) its ability to remove organics from feed water that could foul the RO and (2) that they are more reliable in treating all the feed water than a chemical feed system. companies and boiler water treatment publications. Therefore, the higher the pressure, the more chemical treatment is concentrated outside the boiler in water preparation (chapter 2), and the less internal boiler water treatment and condensate treatment is required. Where feed water is softened, the amount of hardness in the softener effluent is a measure of the softener performance and an indication of when the softener needs to be regenerated. Reliability Assessment for WCTI Zero Blowdown Silica Based Cooling Water Technology by creating water conditions similar to pretr-eated boiler feed water for. These deposits must be periodically removed or damage to the turbine will occur. At the same time, majority of the power plant boilers blow down costly drum water primarily to control the treacherous element 'Silica' in Boiler water. The goal is to improve the quality of water before it is used as boiler feed water. If choice D is selected set score to 1. We Sun Water treatment Estd: 1996, with an aim to provide solution for water & water related services. Live Chat. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Around 60% of damages of power. Scale formation in a boiler can be prevented, satisfy the requirements of feed water and boiler water included in point 4, treating the feedwater and maintaining adequate purge regimes. Water-quality requirements for boiler feedwater depend primarily on the operating pressure and type of boiler. 0 PPM, but boiler feed water parameter is TDS-2, pH-8. 02 mg/L •Pressure type can reduce O 2 to 0. Boiler water circuits are closed loop systems where, ideally, the water is continually circulated. Citation data is made available by participants in Crossref's Cited-by Linking service. BOILER FEED WATER Snap-On Pipe Marker. the information that i have is the properities of the feed water (i. Too high % sat. Feed water heating and deaeration. For example, in a 1000 psi boiler the recommended maximum drum water silica concentration is 2. Boiler water circuits are closed loop systems where, ideally, the water is continually circulated. Phosphate dosing is done in Boiler Drum to separate Silica particles from feed water. - Boiler feed water • Water that serves in any level of the manufacturing process • Common contaminants: Ca, Mg, Fe, Al, Silica. Silica is not listed in the Primary or the Secondary Drinking Water Standards issued by the US EPA. The steam or hot fluid is then recirculated out of the boiler for use in various processes for heating applications. Close control of silica levels will help minimise the frequency of boiler blowdown, which can be expensive and inefficient if performed too often. An efficient and well-designed boiler feed water treatment system should be able to:. Treating boiler feed water is essential for both high- and low-pressure boilers. 69 (USD) / Roll of 25 Each. The objective is to get the liquid into the boiler the simplest and quickest way. IN THE BOILER • Blowdown – two types with two distinct functions • Surface blowdown • Small amount of boiler water drawn off near surface continuously or intermittently • Function is to control concentration of dissolved solids; provide correct boiler water chemistry • Bottom blowdown. The scaling potential of this water was very high for silica and calcium carbonate as shown by Figure 11. Fast Start Combined Cycle / HRSG Plant Combined cycle plant able to have accelerated hot, warm and cold starts. The goal is to improve the quality of water before it is used as boiler feed water. The boiler is then closed to minimize oxygen ingress. Impurities in the feedwater system transport to the boiler where they deposit on surfaces. The formation of scale and sludge can cause tube failures, restrict circulation, reduce system efficiency, and compromise your. Alkalinity-01, M. Silica evaporates in a boiler at high temperatures and then redeposits on the turbine blades. Where feed water is softened, the amount of hardness in the softener effluent is a measure of the softener performance and an indication of when the softener needs to be regenerated. the information that i have is the properities of the feed water (i. it is deposited as pure solid silica. • Proper treatment of boiler feed water is an important part of operating and maintaining a boiler system. The stringent water chemistry requirements of Supercritical power plants makes water treatment in boilers a very critical aspect of power plant operation. 4 Problems Associated with the Final Feedwater Blend 206 7 Waterside and Steamside Problems: Boiler Section Specifics 217 7. Below, we break down the most common boiler feed water issues and how to avoid them to help ensure system efficiency and operational safety. For boilers operating at pressures up to 1000 psig, these specifications are summarized below:. Whatever water is needed to supplement the condensate returned is termed 'make-up water'. The process of water treatment in boilers is not limited to producing high quality DM water. Silica levels required are in the range of 5-20 ppb, depending on the boiler pressure. Four boiler water treatment programs were evaluated for their ability to transport metal ions through 600 psi (41 MPa) waste heat recovery steam generators. compounds in the bulk water. When the phosphate requirement was calculated, there was a mismatch. This treated water is further polished with RO technology to remove salts to either generate cooling tower makeup water or to feed Continuous Deionization technology to produce boiler. 5 Make-up water is the major source of carbon dioxide. – Silica: known to cause hard scaling. water specification for low to medium pressure boiler plays vital role in energy conservation,water pramaeters decides fouling, scaling and energy loss. A ~50 TPH, 110 kg/cmz, 500 DC boiler consumes 1300 tons of fuel 6 per day with GCV of 3800 kcal/kg. Silica (silicon dioxide), in some cases, is an anion. Molybdenum tests are mainly used for coolant water and boiler feed water. It was confirmed that colloidal silica was not there in the feed water. However, water contains minerals and. o (A) Water flows out of the boiler too rapidly with the air cock closed. The more silica present in the boiler feed water, the lower the boiler cycles of concentration must be to avoid scaling. - Accepta 2061 provides outstanding protection from oxygen corrosion along with excellent feed-water and boiler system passivation. This product should be fed into the storage section of the DA tank or near the center of the feed water tank with a chemical injection quill. 2% c) 10% d) 1% 20. Abstract: The effective relations of silica (SiO₂) concentration in boiler drum and generated steam, with respect to pH and pressure for a natural circulation water wall tubes (WWTs) high-pressure (158 and 100 kGք cm⁻²) boiler, (Type TGME-206-COB, Russia) at Ghorasal Thermal Power Station (GTPS). This avoids the need for premature repairs and maintenance work. The removal of hot water from the boiler reduces its efficiency. Feed water with the most suitable quality promotes membrane forming and prevents corrosion. In most systems that have both condensate return and boiler feed units, NPSH is less of a factor for the boiler feed unit, because the feed unit occurs later in the system. Typical tests used for boiler feedwater include: Chloride or salinity Conductivity Dissolved Oxygen Hardness Iron and Manganese pH Silica Sulphite Suspended Solids. 1 Boiler Scaling, Fouling, and Deposition 217. feed water (FW) = makeup water (MW) + Return condensate (RC). Boiler Feed Water Treatment for Industrial Boilers and Power Plants Boiler Water Treatment removes impurities from water outside the boiler in order to minimize scaling. Boiler feed water. Under the boiler/turbine conditions, dissolved silica will form a glass on surfaces like the turbine blades. This includes various types of steam separators, chemical feed lines, boiler feedwater lines, and continuous blowoff lines. • The impurities must be blown down by the discharge of water from the boiler to the drains. Monitoring the ion continuously can allow better control and adjustment of the chemical feed rate to optimize the number of blowdown cycles. Coagulant and polymer improve the clarification process by encouraging individual particles to form fast settling clusters of particles. Main Document. The proper boiler water silica level necessary to maintain less than 0. concentration increases. feed water (FW) = makeup water (MW) + Return condensate (RC). A summary of the treated water quality that might be obtained from the various processes, based on a typical hard raw water supply, is shown in Table 3. provides the alkali required for alkalinity control in the boiler water. Volatilization and carryover of silica with the steam may cause hard, glassy siliceous deposits to form on turbine blades that reduce turbine efficiency. The more silica present in the boiler feed water, the lower the boiler cycles of concentration must be to avoid scaling. Learn More. In the water-steam cycle of power plants, silica is considered one of the major impurities,. Control is achieved by using the constant scum blowdown valve and regular topping up of the feed system with make-up feed water. Boiler feed water. In a 2,400 psi steam generator the recommended maximum is 0. Basic Conversion Factors -- Chapter 60. Boiler water quality is of prime concern to all boiler operators. Boiler water related problems Pure water simply does not exist in nature, and contains impurities. The latter are of particular design and mostly process gas coolers, with process gas within the tubes and boiler water around the tubes. ASME Suggested Boiler Water Limits for Industrial Water Tube Boiler: Silica (ppm SiO 2). This product should be fed into the storage section of the DA tank or near the center of the feed water tank with a chemical injection quill. This avoids the need for premature repairs and maintenance work. The boiler water silica is 0. The boiler receives the feed water, which consists of varying proportion of recovered condensed water (return water) and fresh water, which has been purified in varying degrees (make up water). This produces boiler quality feed water. The most widely recognized scale is white in appearance and is from calcium carbonate that has hastened from hard feedwater. ,Kirkwood Pumps and Process,Nationwide Boiler Inc. The conditions under which vapour silica carryover occurs have been investigated and documented. Although boiler feed water is treated to remove silica and other ionic contaminants, effective long-term control of silica can only be maintained by using the correct monitoring system. Hydrazine will protect the boiler and feedwater systems from oxygen attack and does not contribute conductivity in the boiler feedwater. Such leaks, which transfer raw cooling water directly to the condensate, introduce many impurities, including such deleterious compounds as chlorides, sulfates, hardness, and silica. If silica is present in the feedwater, it tends to precipitate directly as scale at hot spots on the boiler metal and or combines with calcium forming a hard calcium silicate scale. 69 (USD) / Roll of 25 Each. Vaporous silica carryover at a pH of 10. Study 44 Boiler Study flashcards from Joshua C. This is called "dry standby". FEED WATER Parameters Upto 20 Kg/cm2 21 Kg/cm2 to 39 Kg/cm2 40 Kg/cm2 to 59 Kg/cm2 Unit Total Hardness <10 <1. For this reason, the silica content in boiler feedwater must be monitored. Makeup feedwater demineralization with an anion bed can control silica levels in the water if it cannot be controlled economically with boiler blowdown. Boiler feedwater. the plant found that the silica impuri-ties in the boiler water were high, necessitating frequent blowdown operations that consumed large volumes of water and wasted heat energy. 3 FW Contamination from Returning Condensate 203 6. It can be used as a replacement for hydrazine in any boiler up to 125 bar without the associated safety hazards and handling precautions. Note 2: These energy losses are for firetube boilers that are not equipped with stack gas heat recovery equipment such as feedwater economizers or combustion air preheaters. Boiler feedwater often contains impurities, which more. The stringent water chemistry requirements of Supercritical power plants makes water treatment in boilers a very critical aspect of power plant operation. Around 60% of damages of power. 2% c) 10% d) 1% 20. Place color-coded. (Continued on back…) NEWS WATER TREATMENT 8287 - 214th Street W est Lakeville, MN. Scale deposits occur when calcium, magnesium, and silica, commonly found in most water supplies, react to form a continuous layer of material on the waterside of the boiler heat exchange tubes. It should be combined with an oxygen scavenger and condensate corrosion inhibitor. As steam is produced, dissolved solids become concentrated and form deposits inside the boiler. CQ2311 is dosed to ensure the removal of oxygen from the boiler water and to provide polymer to precipitate any hardness in the feed water as a mobile sludge that can be removed from the boiler during the normal blowdown operation. FEED WATER Parameters Total Hardness pH Value Dissolved Oxygen Silica Upto 20 Kg/cm2 21 Kg/cm2 to 39 Kg/cm2 40 Kg/cm2 to 59 Kg/cm2 Unit ×. In some cases external treatment of the water supply is not necessary and the water. This allows the analyser to determine the purity of boiler feed water and steam, and to provide early warnings of condenser leaks or exhaustion of ion exchangers. Maxtreat-3223(s) BOILER FEED WATER TREATMENT CHEMICAL. Keywords: Boiler drum, Silica, Corrosion. Boiler feedwater Measuring the levels of silica in. The CA80SI measures silica concentration from 0. Treating boiler feed water is essential for both high- and low-pressure boilers. 5 Make-up water is the major source of carbon dioxide. boiler water condition (not feedwater water quality) VERBAL DESC - SILICA 2000 DRUM This document contains information that is considered PROPRIETARY AND CONFIDENTIAL in regards to power generation system operation. Boiler Water Pretreatment • Purpose - Statistically 75% of all boiler water problems manifested in the boiler have a rootproblems manifested in the boiler have a root cause in the pretreatment system • Process - Walk through the processes, key factors, monitoring, and operational impacts of pretreatment systems. 365 (B) even cleans already fouled system gradually by its penetrating action by breaking the bond structure of the foulants. Boiler feed water is made of Makeup water and Return Condensate. The term “drum internals” is generally taken to mean all the devices installed within the boiler steam drum. Slowdown: Control of the concentration of chemicals in the boiler water by. 56°C (1°F) for each heat input of 2. I'm with unclesyd and rmw that poor quality boiler feed water is trouble. External Treatment – A Prelude - Chapter 29. Silica removal from boiler water can be done by using dolomite lime or active magnesia in the softener. Hard water contains calcium and magnesium and are minerals that are difficult to wash. Colorimetric system for the monitoring of boiler feedwater, steam, condensate and ion exchangers. The basic process removes the suspended matter before reverse osmosis (dissolved solids reduction) and finally EDI polishing. Feed water consists of condensate, which gets collected after the steam gets condensed by losing heat to the process or radiation losses, flash steam and make up water. A boiler feed water treatment system is a system made up of several individual technologies that address the specific boiler feed water treatment needs. Effective maintenance and repair can extend the life of an aging boiler. Alkalinity is a measure of the capacity of water to neutralize strong acid. Organic scale and corrosion inhibitor with dispersing properties for hard water. Silica concentrations in, e. Feed water is used as desuperheating spray and any contamination or feed water directly enters superheated steam. of boiler volume) may be placed on trays inside the drums to. This allows the analyser to determine the purity of boiler feed water and steam, and to provide early warnings of condenser leaks or exhaustion of ion exchangers. Monitoring the ion continuously can allow better control and adjustment of the chemical feed rate to optimize the number of blowdown cycles. The goal of boiler water treatment is the prevention of. Just 1ppm of silica in the feedwater for a 500W boiler evaporating 1,500 tonnes of water per hour will result in 1 tonne of silica being deposited in the boiler in just one month. If silica is not removed from the boiler feed water, it will concentrate itself on the drum and is carried over in steam to form adherent deposits in the steam passage way distorting the original shape of turbine nozzles and blades. Acce pta 2061 is volatile and alkaline, contributing no. These salts are less soluble when hot than when cold or when there is an excessively high level of silica in relation to the alkalinity of the water in the boiler. Although boiler feed water is treated to remove silica and other ionic contaminants, effective long-term control of silica can only be maintained by using the correct monitoring system. Silica mass balance across a steam pass without antiscalant treatment. It can be practiced only when the drum size is big as in an oil-fired boiler with internal furnace. A summary of the treated water quality that might be obtained from the various processes, based on a typical hard raw water supply, is shown in Table 3. Silica scale is brittle and has a glass appearance. Vecom Marine is a joint venture of Vecom Group & Unimarine Group - Version 3. Our treatment system uses various of advanced technologies, such as UF, O, and EDI to treat raw water and to generate a permeate stream that meets boiler feed water criteria. Feedwater, Steam & Condensate. The higher silica levels led to an excessive blow down requirement in the boiler system. Silica and Boiler Feed Water Silica is a problem for high pressure boilers. A boiler as well has its particular vulnerabilities. Boiler feedwater often contains impurities, which more. When the phosphate requirement was calculated, there was a mismatch. boiler water condition (not feedwater water quality) VERBAL DESC - SILICA 2000 DRUM This document contains information that is considered PROPRIETARY AND CONFIDENTIAL in regards to power generation system operation. Vaporous silica carryover at a pH of 10. A novel and robust correlation was developed to predict the silica solubility in steam of boilers as a function of pressure and water silica content. Salts such. Treatment of boiler feed water is required for preventing excessive heat transfer equipment fouling and erosion of turbine blades. Boiler Feed Water Treatment: Proper treatment of boiler feed water is an important part of operating and maintaining a boiler system. Apa saja yang diukur untuk water boiler, feed water boiler dan condensate boiler dan apa saja parameter-parameternya, dibahas lebih lanjut dalam file berikut:Pertanyaan : Dear all, Sehubungan saya akan mengadakan kontrak dengan supplier Boiler, Mohon pencerahannya untuk Water…. Effective maintenance and repair can extend the life of an aging boiler. Four boiler water treatment programs were evaluated for their ability to transport metal ions through 600 psi (41 MPa) waste heat recovery steam generators. o (A) Water flows out of the boiler too rapidly with the air cock closed. 0 is 88% of that at a pH of 8. had been as high as 7. A refinery in Northern California was unable to meet its desired boiler feed water silica specifications on a consistent basis. The chemical additions to the reaction tanks result in hardness and silica precipitation. Extensive on-line chemical monitoring of both the water/ steam cycle and the water treatment plant on modern power stations, is now a very well established practice. Silica is the only boiler water salt which vaporizes at pressures below 2400 psig. In addition, 3450 RPM motors assure maximum efficiency while maintaining minimum motor horsepower. Basic Conversion Factors -- Chapter 60. Boiler feedwater often contains impurities, which impair boiler operation and efficiency. In a 2,400 psi steam generator the recommended maximum is 0. If the level of silica gets too high, then a 'blowdown' is initiated to remove contaminated water from the boiler. These solids are called scales (boiler stones). In some cases external treatment of the water supply is not necessary and the water. Silica mass balance across a steam pass without antiscalant treatment. 88 Feed water temp. Silica is in all water supplies and requires membrane separation and / or ion ex-change for its removal. particular silica concentration in the boiler water. 4 Advanced Triple Pressure Combined Cycle System with Once Trough Boiler (Siemens) Waste heat boiler in refineries and petrochemical plants may be water-tube boiler or shell boiler. Boiler Feed Water Aijaz Ali 2. Scale deposits occur when calcium, magnesium, and silica, commonly found in most water supplies, react to form a continuous layer of material on the waterside of the boiler heat exchange tubes. Designing and developing feed water, boiler water and steam quality improvement plans. The steam drum is the upper drum of a watertube boiler where the separation of water and steam occurs. Boiler feed water is the most critical monitoring point and the higher the pressure in the boiler is the lower the concentration of silica should be. This product is commonly used in mid to large steam boilers to increase the boiler water pH. Boiler feedwater Measuring the levels of silica in. These salts are less soluble when hot than when cold or when there is an excessively high level of silica in relation to the alkalinity of the water in the boiler. Alkalinity is a measure of the capacity of water to neutralize strong acid. Coagulant and polymer improve the clarification process by encouraging individual particles to form fast settling clusters of particles. The produced water quality for the boiler has conductivity <0. Oxygen in feed water is converted into nitrogen and water through the addition of hydrazine hydrate (N2H4 - H2O). Silica; Organic contamination. morpholine is a base which is used for adjusting the PH of boiler feed water. After plenty of experiment and researches, a new invention has come. A boiler as well has its particular vulnerabilities. In order to avoid scaling of silica on the turbine blades, lower level of total silica has to be maintained in the boiler drum and this calls for increase in blowdown from normal from 1% to 2%, due to which the boiler feed water capacity has to be increased from 20 m3/h to 40 m3/h. As for Max SiO 2 (boiler) till 1000 psi you can use the following table: Drum Pressure (psi) Silica (ppm) 0-220 200. The EPT EOX system treated this water and was now available for reuse as boiler feed water within the existing facilities processes. Water quality of bolier. Boerger, LLC,Boiler & Steam Performance,Clayton Industries,Gorman Rupp Co. To get an idea of the enormity of the problem, let's consider a typical 500MW boiler boiling off 1,500 tonnes of water per hour. Silica is the only boiler water salt which vaporizes at pressures below 2400 psig. From the boiler, impurities carry over into steam causing scaling and turbine blade corrosion. Silica concentration varies from day to day in the boiler feedwater due to changes in plant operation and the efficiency of the warm lime softening process. The purity requirements for any feed-water depend on how much feed water is used as well as what the particular boiler design (pressure, heat transfer rate. This frequency can be specified by a local chemical treatment company. Boiler Tech 4250 combines a chelant with polymeric scale inhibiters and dispersants. BOILER FEED WATER Pipe Markers-To-Go. The steam or hot fluid is then recirculated out of the boiler for use in various processes in heating. DEVELOPMENT OF AN EFFICIENT SLOP FIRED BOILER Speaker Rajesh Singla Silica, SiO2 2. Based on the trace level of hardness in the boiler feedwater, substoichometric levels of chelant are fed (approximately 90% of hardness equivalent). Proper control of boiler water and feedwater will help safety and efficient operation of boilers. Boiler Feed Water Aijaz Ali 2. ) can tolerate. Due to expansion, water will have to be drained from the boiler to prevent it from overflowing. the information that i have is the properities of the feed water (i. Treating boiler feed water is essential for both high- and low-pressure boilers. Boiler feedwater Measuring the levels of silica in. In similar fashion as TOC reports the total concentration of organics (as carbon) without detailing what the organic compounds are, silica reports the total concentration of silicon (as silica) without detailing what the silicon compounds are. al values within range are direct*y proportional to the actual value of TOS of boiler water. 4 Mpa [900 psig]. Silica needs to be controlled at DM plant also. Dictated by boiler water treatment. the pH of the boiler water will decrease until acid conditions result in corrosion of the metal surfaces. Water Chemistry and Pretreatment 2. 04 ppm in the steam. Another important source of silica in water is the sand watertreatments filter. Further investigation deter-mined that the source of the problem was colloidal silica in the form of fine mud in the boiler feed water. The higher blow down rates were significantly affecting the refinery's water, chemical, and natural gas costs. When feed water temperature is elevated to boiler water temperature, the solubility of scale forming salt is decreased, and solid scale begins to form on the boiler system. Installing a water treatment system in place before a boiler feed system will remove dissolved and suspended solids as well as organic material that may be present in the feed water. Impure feed water increases blow down which is uneconomical. In the water-steam cycle of power plants, silica is considered one of the major impurities,. Boiler water quality is of prime concern to all boiler operators. Maxtreat-3220(s) BOILER FEED WATER TREATMENT CHEMICAL: It reduces deposition of calcium and iron compounds in coils. Starch indicator solution. Most of the time you have more restrictios with steam quality in the ST that in the HRSG or in the Boiler. These should be maintained within the boiler manufacturer guidelines or those of BS 2486. The liquid phase is recirculated to the evaporator. It is a blend of oxygen scavenger and polymers. Therefore, good internal boiler water treatment programs are necessary. Other sampling points can be inside drum boilers and water returning to the boiler from the condenser to ensure silica limits are within specification. Power Plant Converts Gray Water into Boiler Feedwater using HERO™ Technology The Facility The Bajio Power Project is a 600 MW combined cycle project owned by Energía Azteca, a Mexican project company jointly owned by InterGen and American Electric Power. Boiler Blowdown Standards: Boiler blowdown is primarily used to control dissolved solids in boiler water, and to remove loose scale and sediment contaminants. The boiler is then closed to minimize oxygen ingress. Login into Examveda with. Contaminants of Boiler Feedwater Many of the localized corrosion and embrittlement mechanisms that will be discussed below are operative in steam systems when moisture is carried over, or contaminates are volatilized in the steam phase (i. For example, in a 900 psi boiler the recommended maximum drum water silica concentration is 2. Boiler Feed Water Aijaz Ali 2. Vaporous silica carryover at a pH of 10. The higher silica levels led to an excessive blow down requirement in the boiler system. Silica Boiler Feed Water: Few Recommended Actions or Guidelines to Prevent Silica Deposition & to Maintain Correct Water Chemistry Parameters As we all must aware that prevention is better than cured. Managing Silica in Boiler Feed Water Date :: 07 - June - 2015. Solution Chemistry Impact on Silica Polymerization by Inhibitors 175 not. Most raw waters contain bicarbonate (HCO-). External Treatment – A Prelude - Chapter 29. Organic scale and corrosion inhibitor with dispersing properties for hard water. WAC polishing units will remove the residual water hardness to meet boiler feedwater specifications of less than 0. 97% of the colloidal silica was removed, the average initial concentration being 250 ppb and the average final product having less than 8 ppb. Volatilization and carryover of silica with the steam may cause hard, glassy siliceous deposits to form on turbine blades that reduce turbine efficiency. The amount of silica expected in the steam from a particular boiler is shown by the intersection of the boiler pressure line and boiler water silica line. in two months time without blowdown, we have observed decreasing pH in the feed and boiler water even with 2-3 ppm phosphate. Especially if colloidal silica is present in the makeup water. The feed water silica concentration is very high at 115 mg/L high pH value of 7. 5 ppm as CaCO 3 pH Value 8. Scale deposits occur when calcium, magnesium, and silica, commonly found in most water supplies, react to form a continuous layer of material on the waterside of the boiler heat exchange tubes. Silica analysis is carried out via differential photometry using a leading-edge technology thermostatic cuvette module for non-sample contact at the detector. The polymeric form of silica is not thermally stable and when heated in a boiler reverts to the basic silicate monomer. Feed/Boiler Water Limits Review use ASME Consensus tawe 3:. Feedwater heater Boiler efficiency is improved by the extraction of waste heat from spent steam to preheat the boiler feedwater. 1 Overview of Pre-Boiler Section Waterside Problems 192 6. The steam or hot fluid is then recirculated out of the boiler for use in various processes for heating applications. Note that silica’s volatility increases with boiler pressure. Improvement of a boiler feedwater system using six sigma analysis ABSTRACT Industrial boiler systems are used in manufacturing plant to generate steam for the purpose of production. Maxtreat-3220(s) BOILER FEED WATER TREATMENT CHEMICAL: It reduces deposition of calcium and iron compounds in coils. This treated water is further polished with RO technology to remove salts to either generate cooling tower makeup water or to feed Continuous Deionization technology to produce boiler.