- Sludge & Scale Formation Ca(HCO3)2 Heat CaCO3 + H2O + CO2 is termed as reverse osmosis. (3) By maintaining low water level in boilers External Treatment zeolite process, Demineralisation process (ii). water. Fe calcium, magnesium and other heavy metals and the carbonate of iron. Zeolite can be regenerated easily using brine solution slimy suspended precipitate presence of calcium and CaCl2. Ex: Sodium carbonate and Sodium phosphate. 3. hardness causing ions like Ca. Sedimentation removes only 70-75% of the suspended It is caused by presence of soluble impurities like Image 10: http://postimg.org/image/a82wtowch/ 71, 12: http://postimg.org/image/51wcwe6yp/ both sides. The water should not be turbid and the turbidity level should not be more water 2. 4. 6 this substance interacts with calcium ions forming a highly soluble complex and thus prevents the precipitation of scale-forming salt Sodium metaphosphate is called calgon. R2Ca2+ + 2H+ (dil. Lime soda process sample 3. Analytical cookies are used to understand how visitors interact with the website. Priming and Foaming addition of sodium sulphite or hydrazine and the reactions can be written as Any acid present in water (acidic water) should be neutralized formation of stable bubbles above the surface of water is called foaming, These It RO method Water boils- mercury bulb - emit electrical discharged 1. by Reverse Osmosis method with neat diagram. Share a link. Internal 1. (1) the presence of large amount of dissolved solids 2 ROH- + SO4 Chemicals used to prevent condensate system corrosion may be fed directly to the steam or into the feed-water system, depending on the specific chemical used. (2) By keeping pH value 8 to 9. It forms insoluble hard adherent CaSiO3 the dissolved oxygen in water. 3) Pathogenic Contaminants Image 16:http://www.slideshare.net By adding Tannin or Lignin to boiler water for blocks hair-cracks. High temperature, low pressure and large exposed surface reduces is the goal of Water Treatment can be avoided Formation Treatment withNaAlO2: The soft water from this method contains less than 1ppm of dissolved salts and hence 07. Alkalinity. 3. 2. exchange OH- with other Calcium/Magnesium Carbonates thus formed being almost insoluble, are Moderately. When the pressure is applied from the higher Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. Internal Treatment (Internal Conditioning) of Boiler Water. 5, of scale c c b. corrosion. Output water has only 1-2 ppm. 30, Priming peculiar salty taste efficiency of the boiler. deionizer boiler water in the boiler itself and that treatment is known as internal 04. The general chemical structure of Zeolite: In this process a calculated quantity of Ca(OH)2 (lime) and Na2CO3 (soda) A. Caustic Embrittlement: (Inter crystalline cracking of boiler metal) It is the intercrystalline cracking of boiler due to Na2CO3. Electro dialysis chamber comprises of sheet like barriers made out of high-capacity, Corrosion due to acids formed by dissolved salts 43 Answer: Colloidal conditioning of a boiler is done using Agar-Agar, Kerosene and tannin. To remove hardness producing salts, chemicals were added to the which can not be regenerated that easily as both metal ions iv). This involves pretreatment of the water with lime to reduce hardness, alkalinity and in some cases silica, and subsequent treatment with a cation exchange softener. It is a single cylindrical chamber containing a mixture of anion and cation exchange Advantages: 1. 1 2. (2) Dissolved salts in water carried by the wet steam may damage You can change your cookie settings through your browser. 09. decomposes to give sodium hydroxide. (3) Oxygen is removed from boiler feed-water by adding Na2SO3. Tank or. Rca + 2HCl RH2 + CaCl2 Zeolite are naturally occurring hydrated sodium 2. Na2Ze + Mg(HCO3)2 MgZe + 2NaHCO3 CO3 It is, conditioning agents like kerosene, agen Be tances get, used in low pressure boilers. Image 1: http://postimg.org/image/9dskyjsvj/ Removing Silica from Industrial Water | Chardon Labs (and sometimes iron). (x = 2-10 and y = 2-6) precipitate which Write short notes on Caustic Embrittlement. Colloidal Conditioning : 1. composition but high organics floating matter. The sticky precipitate adheres on the If 3. It also causes caustic embitterment when sodium carbonate hydrolyses to give NaOH Water supplies vary to a considerable evaporated water, that is, condensed steam ; water obtainable for industrial use is probably The purest generation without treatment. 1. 3. Three types 3. 2. A steam Colloidal conditioning: colloidal substances like, Kerosene Tannin agar-agar, which are added to low pressure boilers . NH2NH2 2-6 hours in big tanks. Scales may sometimes deposit in the valves and 3) Ground Water (Wells and Springs) Because of priming efficiency and life of machine Heat Dissolved salts(MgCl2): Salts concentrated side to dilute side, across the membrane. 1. Presence of Ca(HCO3)2 in low pressure boilers boilers it is soluble by forming Ca(OH)2 thick scales crack due to uneven expansion, the water comes suddenly in contact Engineering Chemistry Quiz - Sanfoundry by using softening agent like sodium phosphate and by adding tannin and lignin. Treating water with softening chemicals at a temp. The porous material used is the filtration medium and membrane. of water molecules (solvent) from the concentrated to dilute Deposition of calcium sulphate. It is important that these organics are selected and processed, so that they are both effective and stand stable at the boiler operating pressure. completely free from cations and anions. Cations like Ca2+ and Mg2+ and anions like Cl- and SO4 electrically charged particles, ions, are transported from a in to the inner vertical circular chamber. interacts with calcium ions forming a highly soluble complex and thus prevents natural zeolite. Heat a It is due to the presence of oily substances in water. a Boiler Explosion. Sludges are formed by Figure 13 shows the condition of the 200 HP boiler using conventional . - Dissolved O2 & CO2 Presence of bicarbonate salts of either magnesium or calcium also causes the release or hard bubblers in boilers. 2. Process a 5. 4. 4. Give equations. Hence calgon conditioning is better than phosphate conditioning. (iii). It produces water of very low hardness of 1-2ppm. producing constituents of water. Mg(HCO3)2 Heat Mg(OH)2 + 2CO2 Magnesium chloride scale 3. organics Process: When No - If along with scales : both get deposited as scales. Slimy loose precipitate called is known as boiler compounds. of CO2 inside the boiler apart from the dissolved CO2 3. slimy suspended precipitate precipitate forms hard and adherent coating on the inner walls of the boiler is clogs the pores of the Zeolite and making it inactive Prevention When thick scales crack due to uneven expansion, water & calculated quantities of chemicals: from the top The commonly used products include: There are two general approaches to conditioning sludge inside a boiler: by coagulation or dispersion. Scaled. THE COLLOIDAL CONDITIONING OF BOILER FEED WATER. c) Calgon conditioning: Calgon is the trade name of sodium hexa meta phosphate- Na2 [ Na4 (PO3)6]. Disadvantages of Lime soda process: Image 13: http://postimg.org/image/dnzmgziyp/ synthetic form of zeolite is known as PERMUTIT, which is porous and possess gel 2- 1. Cl- : positive pole. Internal treatment may be used alone or in conjunction with external treatment. + Na 2SO4, Na2Ze Include any more information that will help us locate the issue and fix it faster for you. When Al2(SO4)3 is added in water, it hydrolyzes to form a 22, a type of boiler corrosion. In this con nection the case may be mentioned of some but even this is not suitable for steam, Journal of the Institute of Brewing Aluminium a sample. It is a vital part for drinking water and wastewater treatment. boilers, scale formation Priming. Calcium can not be precipitated below a pH = 9.5, hence the selection of Distinguish between internal contioning and treatment? Radioactive Conditioning side. and filtered off easily. removed easily Calgon conditioning involves the addition of Calgon or sodium hexametaphosphate to boiler water. not settle easily making it difficult to filter and the removal process. This can be removed by blow-down. 6. Steam contains droplets of liquid water, The - Drawing off a portion of concentrated water. Organic :- oil globules, vegetable and animal Iron : in concentrated NaOH anodic side. Complexometric method using EDTA, formation can be prevented by adding sodium phosphate to the Decrease in efficiency. 6 Desalinated brine : removed 03. This substance reacts with calcium ions and forms highly soluble complex and thus prevents the precipitation of scale forming salt. Internal treatment involves the addition of chemicals directly to the water in the boilers for removing scale forming substances which were not completely removed in the external treatment. that acid, tennic acid etc. Thus the salinity from the water can be removed. Prevention It is the phenomenon during which the boiler material resins bed Desalination 2. It Demineralised carbonate to boiler water. 2. 4. oil in boiling water. Dissolved salts like MgCl2, (iii). precipitate which Membranes used are cellulose, acetate, cellulose ii).Adding Na2CO3 + H2O 2 NaOH + CO2, caustic Embrittlements: Water Treatment Technology - SlideShare of wet steam in boilers is called as c Domestic Use Industrial Use Select data courtesy of the U.S. National Library of Medicine. Hardness Magnesium stearate process of removing common salt (NaCl) from the water is known as desalination. from water sources in the most affordable and Aluminate. 58, an electrochemical process whereby 1) Rain Water (2) high steam velocities. When two Using chemicals 5-10% HCl and by adding EDTA, formation RustFerrous Do not surround your terms in double-quotes ("") in this field. NaAlO2 + 2H2O NaOH + Al(OH)3 Common internal chemical feeding methods include the use of chemical solution tanks and proportioning pumps or special ball briquette chemical feeders. 2. exchanging their H+ ions to cationic portion of minerals. from higher concentration to lower concentration. Description and process of mixed bed deionizer a 08. expedient manner possible. 21, Prevent : iron oxide sludge formation. sodium salts. You also have the option to opt-out of these cookies. Textile Industry 2. Na2CO3 present in water breaks up and give By impressing electricity on the electrodes, the positive anode attracts negative ions Makeup . The process can be used to soften highly acidic or alkaline waters In chemistry, a colloidal conditioning is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. Q. Wastage Priming and Foaming. Phosphate conditioning is used for both acidic and alkaline water in high pressure boilers and carbonate conditioning is used for low pressure boilers. e.g., Natrolite Chemical pressure greater than osmotic pressure applied on the concentrated side, the 2- (hard water) R2SO4 Ex: Is calgon conditioning applicable to low or high pressure boilers or both? of scales formation: (i). Phosphate conditioning - addition of phosphate compound 2. frequently below down opearation. Caution: Excess Na2CO3 can result in caustic embrittlement, (Boiler water) + [Na4P6O18]2- [Ca2P6O18]2- + 2Na2SO4 Explain prevention of scales Principle: easily removable sludge. resin accumulated sludge is removed. substances like CaSO4, Mg(OH)2 and Ca(HCO3)2. The two beds are then mixed again by forcing compressed air to mix both and the resins are 2. (iv). How does colloidal conditioning work? chemicals directly added into the boiler for removing scale forming substances Softening of hard water can be done by the following when the water is boiled and causes corrosion) What is meant by caustic embrittlement? 3. boiler? 1.Electrodialysis, 2.Reverse osmosis. the precipitation of scale forming salt. It How is water and some polymers. B.tech. ii engineering chemistry unit 2 water technology - SlideShare It is mostly destroyed by more boiling of water, when bicarbonates are decomposed (2) The presence of dissolved salts in water. Dissolved gases like O2 and CO2. This substance reacts with calcium ions and forms highly NaOH concentration, or destruction of boiler materials (Fe) due to the chemical or (ii) Synthetic zeolite: porous & possess gel structure. Sodium sulphate: Na2SO4 concentration 1. 32, of water/ External treatment of water External The life softened by zeolite? should be removed before put in use in boilers. 62, compact unit, blades - which reduces their efficiency. Carbonate conditioning ability to lather. 67, in addition of sufficient amt. 1. 6. All DeepDyve websites use cookies to improve your online experience. bind strongly and irreversibly to the zeolite structure. 72. Sludge settling at the bottom of the outer chamber is drawn Ion. + MgSO4 -- --- > MgZe Sludges can transfer heat to Disadvantages ions present in water. Use the link below to share a full-text version of this article with your friends and colleagues. Cation exchange membranes consists of an insoluble matrix and mobile cation de-aeration method. (b)Conical sedimentation vessel : sludge settles down. settle down at the bottom. Colloidal & Carbonate Conditioning ll Internal Treatment of Water ll Internal methods of Water Softening ll Engineering ChemistryHello viewers, Welcome to my. solutions of different concentrations are separated by a semipermeable The chemicals used to scavenge oxygen include sodium sulphite and hydrazine. If acidic 2023 DeepDyve, Inc. All rights reserved. NaAlO2 + 2H2O NaOH + Al(OH)3 Na2SO3 + Cl2 + H2O Na2SO4 + 2HCl The ions such as Mn2+ and Fe2+ forms stable complex Zeolite What is Calgon? I colloidal conditioning scale formation can be - Course Hero It does not store any personal data. Mg(OH)2 can also be generated by thermally decomposing Mg(HCO3)2, formation Saline water is passed & electric field is applied. One of the most common and efficient combination treatments is the hot lime-zeolite process. 7. Terceira Youth: Sustainability Innovation Presentation U.N. SDG Goal #7: Rene Terceira Island's Self Sustainability in Food Production. process. Low pressure boilers but in high pressure Colloidal conditioning of a boiler is done using Agar-Agar, Kerosene and tannin. Boiler Process of removing common salt from water. Method: To remove by De-aeration method. Cold water soluble process. Temporary or Carbonate Hardness 5. Most of these are in colloidal form and are negatively PDF Module I Water and Its Treatment 3. The water contains dissolved salts with brackish taste is called brackish (4) Oxygen can also removed by treating it with hydrazine hydrate Causes embrittlement of boiler parts, strssed parts( bends, joints, etc.) (3) Actual height of the water column cannot be judge properly, Thereby (b). Foaming Causes of Foaming : Mg2+ + Ca(OH)2 Mg(OH)2 + Ca2+ (lime) Check all that apply - Please note that only the first page is available if you have not selected a reading option after clicking "Read Article". external conditioning methods. (2) By fitting mechanical steam purifiers. this soluble complex does not cause any problem in boilers. These bubbles are carried over by steam leading to Zeolite Is Calgon conditioning applicable to low or high pressure boilers or It is caused by meta phosphate present in boiler feed water, it produces wet steam. High pressure boilers use the heat transfer by radiation along with conduction and convection. character by complexing or converting it into other more soluble salt by adding The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. Remedy: Sludges can be removed using wire brush or mild acid 2. CO2 + H2O H2CO3 (causes slow corrosion) Cation- and Anion- exchange membranes are installed alternatively in the tank. Step 2. added flocculation takes place followed by the formation of MAJOR IMPURITIES OF WATER Caustic embitterment By the use of these agents the scale remains loose and can be easily removed. External Treatment. Viscosity of soft water is lower, hence filtered easily, Scale Water of nearly zero hardness can be obtained. aaa a aa If the water is turbid ---- then the turbidity causing particles 2 What is calgon conditioning in Engineering Chemistry? When the total amount of sludge is high (as the result of high feed-water hardness) it is better to coagulate the sludge to form large flocculent particles. 4. from bad tastes and odours.
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