Looking for a Tutor Near You?

Post Learning Requirement »
x

Choose Country Code

x

Direction

x

Ask a Question

x

x
x
For better view click here
x
Hire a Tutor
DISCOVER

Water

Loading...

Published in: Mechanical
29,520 Views

Presentation on Water.

Trinity A / Chandigarh

year of teaching experience

Qualification:

Teaches: Indian National Mathematical Olympiad (INMO), Mental Maths, Olympiad Exam Preparation, Regional Mathematical Olympiad (RMO), Advanced Excel, Basic Computer, MS Office, School Level Computer, Mathematics, Statistics, Science, Social Studies, B.Tech Tuition, Drawing, Mechanical, AutoCAD Training, French, German, Study in Germany

Contact this Institute
  1. Water Its Treatment
  2. Syllabus (CU-2016) Specifications for drinking water (BIS and WHO standards), purification of domestic water, Types of hardness, unit of hardness, Determination of hardness by EDTA method; water softening (Internal Treatment) lime soda process (numerical problems), zeolite process, ion exchange process. Boiler feed water, Boiler corrosion and caustic embrittlement; Priming and Foaming, Formation of solids (scale & sludge) their causes, disadvantages & prevention. 2
  3. Introduction For the existence of all living things water is essential. Without water we cannot survive. Almost all human activities domestic, agricultural and industrial demand use of water. Water from any source has to be treated before its use. The treatment to which it is subjected depends upon its use. If it has to be used for drinking purposes, the treatment would include removal of objectionable colour, taste and pathogenic micro organisms, whereas the water for industrial use require the removal of dissolved salts if it is used for steam generation. In this section we will discuss about the analysis of water and treatment of water for its industrial and domestic use. 3
  4. Sources of water Surface water :-The water which comes from surface through rain. eg :- rain water, river water & sea water. Underground water :- This water comes from rain that falls on earths surface & then goes into the ground water & travel down the impervious (cracks) layers of earth, thus forming ground water. eg :- spring water & well water. 4
  5. Impurities in Water Silica, clay etc C02, 02, H2S Bacteria & other Micro-organisms like algae & fungi Carbonates, Bicarbonates, Chlorides & Sulphates of Ca, Mg. 5
  6. Types Of Water HARD WATER SOFT WATER
  7. HARD WATER Does not form lather with soap easily Contains dissolved salts of Ca More wastage of time & fuel as boiling temp. of water gets increased due to impurities More consumption of soap by hard water SOFT WATER Forms lather with soap easily Does not contain dissolved salts of Ca & Mg Less wastage of time & fuel Less consumption of soap by soft water 7
  8. Hardness of water Hardness is the soap consuming capacity of water Hardness of water is due to the presence of Ca and Mg salts in it. Other ions responsible for hardness are A13+ Fe3+ and Mn2+ If Ca and Mg salts are present in water then they react with the soluble sodium soap to form insoluble salts calcium and magnesium. 2C17H35COONa + caS04---» (C17H35COO)2Ca + Na2S04 Sodium stearate Insoluble salt 2C17H35COONa + MgC12---» (C17H35COO)2Mg + 2NaC1 8
  9. Types Of Hardness TEMPORARY PERMANENT
  10. Temporary Hardness Caused by the presence of dissolved bicarbonates of Ca, Mg and. This hardness is also known as alkaline hardness. Easily removed by heating : Heat cac03 1 + + c02 T Heat c02 T 10
  11. Permanent Hardness Due to the presence of sulphates and chlorides of Ca & Mg Cannot be removed simply by boiling. Special methods like lime soda process, zeolite process, ion- exchange method are used for the removal of permanent hardness. 11
  12. egree of Hardness in terms of CaC03 equivalent Hardness is expressed in terms of CaC03 equivalents. Reasons for choosing CaC03 as the reference standard for calculating hardness of water is . mol. wt. is 100 that makes mathematical calculation easier. The most insoluble salt and can be easily precipitated in water treatment process. 12
  13. How to calculate harness in terms of CaC03 equivalent Hardness in terms of CaC03 equivalents mol. mass of CaC03 = wt. of hardness producing sub. mol. mass of hardness producing sub.
  14. Units of Hardness a) b) c) d) parts per million Milligrams per litre Degree Clark Degree French ppm Mg/l OCI OFr parts of CaC03 equivalent hardness per 106 parts of water. no. of milligrams of CaC03 equivalent hardness per litre of water. parts of CaC03 equivalent hardness per 70,000 parts of water. parts of CaC03 equivalent hardness per 105 parts of water. Relation between various units of hardness Ippm = Img/l = 0.10Fr = 0.07 OCI
  15. Boiler feed water For steam generations, boilers are used o if hard water is fed to the boiler, various problems are faced by boiler : Scale and Sludge formation Priming and Foaming Boiler corrosion Caustic embrittlement 15
  16. Sludge & Scale Continous evaporation of water takes place & conc. of dissolved salts gets increased & at saturation point forms ppts. on the inner walls of the boiler. Sludges : If loose & slimy ppts formed. Scales . If sticky, hard & adhernt coat formed. precåpe.ato suspended in water (sLdge) Sludge Heat Water wat Scale Hard adherin on inner walls of bodor (scale) Heat 16
  17. Sludge 'FORMATION: Where flow of water is slow At colder region By substances which have greater solubility in the hot water. MgC03, MgC12, CaC12, MgS04 etc. 'DISADVANTAGES: Poor conductor of heat hence more consumption of time and fuel. Disturbs functioning of boiler & settles in the regions of poor water circulation. 'PREVENTION : By using soft water By using blow down pipe operation .
  18. Scale 'FORMATION : Decomposition of : CaC03 + H20 + C02 Soft Scale + C02 CaC03 + H20 Deposition of CaS04 : Soluble in cold water As temp. solubility of CaS04 hard scale Hydrolysis of Mg salts MgC12 + 2H20 Presence of (Si02) Mg (OH)2 + 2HC1 18
  19. Scale 'DISADVANTAGES O Fuel Wastage Lowering of boiler safety Decreased efficiency Danger of explosion Removal Using wire brush By using chemicals : CaC03 scales by 5-10% HCI CaS04 scales by EDTA Blow down pipe operation By giving thermal shocks 19
  20. Scale Prevention External Treatment By using soft water INTERNAL TREATMENT Colloidal conditioning : Addition of organic substances such as tannin, Agar- Agar Phosphate conditioning : o CaC12 + Na3P04 ----..-.-.-...----..--..-.--.-.-...--.-...-> Carbonate conditioning o CaS04+ Na2C03 ----.-.-.-.--.-....-...-.-..-.-....-..-.-.--.> Calgon conditioning Treatment with sodium aluminate : o NaA102 + 2 H 20 -----.-.-.-----.-.---.-..--..-.--.---> Calcium phosphate + 6NaCl caco + Na2S04 Soluble complexes of Ca ions + NaOH 20
  21. ifference between u ge Scale Sludge Soft, loose & slimy precipitates. Non-adherent deposits & can be easily removed. Formed by substances like CaC12, MgC12, MgS04 & MgC03 Formed generally at colder portions of the boiler. Decrease the efficiency of boiler but are less dangerous. Scale hard deposits. Stick very firmly to the inner surface of boiler and are very difficult to remove. Formed by substances like CaS04, cac03 & CaSi03. Formed generally at heated portions of the boiler. Decrease the efficiency of boiler & chances of explosions are also there.
  22. Priming and Foaming Priming process of making wet steam when some of liquid particles are carried along with steam a cause Presence of dissolved salts high steam velocity Sudden boiling Sudden increase in steam production Foaming Formation of bubbles in the boiler continuously a cause presence of oil that reduces the surface tension 22
  23. Priming & Foaming Disadvantages Reduce the efficiency Difficult to maintain proper pressure Wastage of fuel Actual water level can not be accessed • Prevention Removal of priming foaming substances Removal of Scale & sludges Avoid rapid changes in steaming rate Change of boiler water from time to time Using antifoaming agents e.g. castor oil Addition of a chemical NaA102 to remove water 23
  24. Boiler Corrosion The chemical or electro-chemical eating away of metal by its environment in a boiler • Cause Dissolved Oxygen 2Fe +2H20 + 02 Dissolved C02 : C02 + H20 Acids from dissolved salts : MgC12 + 2H20 + 02 + 2HC1 + H2 2(Fe203 .2H20) H2C03 FeC12 FeC12 + HCI 2H20 + 2HC1 24
  25. Boiler Corrosion Disadvantages Shortening of boiler life Leakages of joints and rivets Increased cost of repairs and maintenance Removal of boiler corroision . Removal of 02 : 2Na2S03 + 02 + 02 N2H4 Removal of C02 : 2NH40H + C02 Removal of acids : By adding alkali 2Na2S04 + 2H20 (NH4)2C03 + H20 25
  26. Caustic Embrittlement formation of brittle and incrystalline cracks in the boiler shell due to the accumulation of caustic substances • Cause Presence of alkali-metal carbonates and bicarbonates in feed water presence of sodium sulphate. Sodium carbonate is used in softening of water by lime soda process, due to this some sodium carbonate may be left behind in the water. 26
  27. •Process Na2C03 used for softening of water & some of which remain unreacted Na2C03 + H20 2NaOH + C02 As Conc. of NaOH increases, water flows into minute hair cracks by capillary action. As water evaporates, conc. of NaOH increases further and react with iron of boiler, (thereby dissolving Iron of boiler as Sodium ferroate), hence cause Embrittlement. This causes embrittlement of boiler parts such as bends, joints, reverts etc, due to which the boiler gets fail.etc. prevention : Use of Na3P04 instead of Na2C03 By adding tanin & lignin that blocks the hair cracks By adding NaS04 that also blocks the cracks 27
  28. O Softening Methods The following methods are used : Lime soda Process Zeolite softening process Ion exchange process 28
  29. Lime — Soda Process Treatment of water with calculated amount of lime Ca(OH)2 & Soda (Na2C03) which results in the formation of insoluble ppts. of Ca & Mg that can be removed by filteration. Cold Lime Soda Types Hot Lime Soda 29
  30. Cold lime soda process Driving belt Chemicals Motor (3--Rawwater feed inlet (soda + lime + coagulant) -..............-..............................+ feed inlet Wood fibre filter Stirrer paddles Stirrer Slud e outlet -........> Filtered softened water outlet Outer chamber Inner chamber Sedimented sludge CaC03, Mg(OH) 30
  31. Hot Lime Soda Process Raw water feed inlet superheated steam inlet Reaction tank Conical sedimentation tank Precipitated sludge Chemicals (lime + soda) feed inlet Softened water Sand filter Precipitated sludge outlet Fine sand layer Coarse sandlayer Gravels layers Filtered softened water outlet 31
  32. Cold Lime-soda Method Carried out at room temperature. Slow process Coagulant A12(S04) is added Dissolved gases are not removed . water obtained is of hardness 60 ppm. Hot Lime-soda Method Carried out at high temperature,almost at b.pt.of water. Fast process No need of Coagulant. Dissolved gases are removed . water obtained is soft of hardness 15-20 ppm. 32
  33. Impurity CaC12 CaS04 Mgc12 MgS04 Mol. Wt. 162 146 111 136 95 120 Requirement s s L-I-S 33
  34. 100 parts by weight of CaC03= 74 parts by weight of - 106 parts by weight of Na2C03 Total Lime Requirement 74 (bicarbonate hardness + permanent hardness due to Mg2+, (Vol. Of Water)(% purity of lime 100 Total Soda Requirement = 106 (permanent hardness due to Ca2+, Mg2+, ) (Vol. Of purity of soda) 100 34
  35. Numerical Problems Calculate the amount of lime (91 and soda (97.2%) required for softening 1 million liter of water which contains Ca(HC03)2= 30.5 ppm, Mg(HC03)2=35.5 ppm, MgS04 = 20.2 ppm, CaS04 =24.0 ppm, CaC12= 25ppm and NaCl=10 ppm. Also calculate the temporary and permanent hardness. 35
  36. Zeolite or Permutit process Na20A1203 XSi02 yH20 Where x = 2 - 10 , y = 2—6 Can be written as Na2Ze where Ze = OA1203 xSi02 yH20 exchanges reversibly its sodium ions with hardness producing ions( Ca & Mg) in water. 36
  37. Principle of Zeolite process Softening Process . Na2ze + Na2ze + Regeneration : Caze + 2 NaC1 Mgze + 2 NaC1 Caze + 2 NaHC03 Mgze + 2 NaHC03 Na2ze + CaC12 Na2ze + MgC12 37
  38. Zeolite process 1 laid water inlet— Zeolite bed Injector— NaC1 Solution C.:tavel - sink Soft v.ater outlet 38
  39. Ion Exchange or De-ionization or De- mineralisation process Hard water is allowed to pass through ion exchangers when soft water, free from all the minerals and hardness causing as well as the other ions is obtained. Cation Exchange Column represented with its H+ ions Types Anion Exchange Column represented with its OH- ions 39
  40. ocess Cation Exchange column : 2RH+ Cation exchange resin + Ca+2 Anion Exchange column : R'OH Anion exchange resin 2R'OH Anion exchange resin Regneration: S 04-2 CationExchange column : R2Ca+2 Saturated Cation exchange resin dil. acidic sol. Anion Exchange column : R2'S04-2 Saturated anion exchange resin 20H dil. Basic sol. R2Ca+2 Cation exchange resin R'CI- Anion exchange resin R2'S04-2 Anion exchange resin 2RH+ Regenerated Cation exchange resin 2R'OH Regenerated Cation exchange resin OH 20H ca+2 washings S 04-2 washings 40
  41. Ion Hard Water -..........................> Exchanger Injector —+ Cation Exchanger Bed To Sink Acid Regenerator (DIL. Acidic Solution) Gravels Anion Exchanger To Sink Alkaline Regenerator (DIL. NaOH Splution) + Injector 41
  42. Determination of hardness by EDTA method Hardness of water is estimated by complexometric titration with disodium salt of EDTA (ethyl diamine tetra acetate) Erichrome black—T (EBT) is a dye is used as indicator. EBT is added to hard water producing wine red coloured complex is titrated with EDTA solution of known strength. The colour of the complex changes from wine red to light blue indicating the end point. pH is maintained at 10 using NH CI-NH OH buffer. EDTA titration https://www.youtube.com/watch?v=hTY9JBllUVg
  43. Structure o -EDTAznd metal- EDTA complex HOOC-CH HOOC-CH2 structure of EDTA M2+ + EBT blue CiliCOOll M-EBT wine red M-EBT+ EDTA M-EDTA+ EBT wine red colorless blue
  44. Specification for drinking water •It should be bacteria free • It should not contain any suspended impurities •It should not have bad taste. • It should not contain toxic materials such as lead, arsenic, chromium and copper. •pH should be in the range 7 to 8.5 •It should be slightly alkaline •It should be free from dissolved gases like H2S, C02 etc. "Its turbidity should be less than 10 ppm. It should be cool It should be reasonably soft.
  45. Text books, references and links o Jain P C and Jain M: Engineering Chemistry (15th Edition) 2006 DhanpatRai Publishing Company, New Delhi. ChawIaShashi: A text book of Engineering Chemistry (3rd Edition) 2010 DhanpatRai Publishing Company, New Delhi. http://www.slideshare.net/textilevandana/waste-water-and- its-treatment-in-textile-industry 45

Need a Tutor or Coaching Class?

Post an enquiry and get instant responses from qualified and experienced tutors.

Post Requirement

Related PPTs

Upload PPTs

If you have your own PowerPoint Presentations which you think can benefit others, please upload on LearnPick. For each approved PPT you will get 100 Credit Points and 100 Activity Score which will increase your profile visibility.

Upload Now
Home > PowerPoint Slides > Water