Fully Automatic R O + D M Plant 10,000 LPH

Product SpecificationProces Description:RO PlantRaw water gets collected inraw water tank; the raw water feed pump feeds it to the Multi Grade Filter.The Multi Grade Filter will remove all suspended solid up to 50 micron particle size. The filtered water is then feed to the RO system through a cartridge filter.

The5 micron cartridge filterremoves all suspended solids greater than 5-micron size.Antiscalantwill be injected in the feed water at the beginning of cartridge filter to prevent precipitation of calcium carbonate salt on the membrane and prevent it from fouling. AlsoAcidwill be injected in feed water before cartridge filter to maintain feed water pH in range 6-7. At this pH, solubility of scale forming salts is increased there by minimizing membrane fouling.

The raw water will now be feed into theR. O moduleafter pressurizing it through ahigh pressure pump. The R.O. module consists of semipermeable membranes. When the pressurized water is fed to the R.O. membrane, the membrane rejects salt ions and only water is allowed to pass through the membrane. The salt ions are continuously washed out of the module (reject/concentrate stream) and the permeate stream is the desalinated product water stream. Some amount of the concentrate stream is recycled to the RO module inlet to minimize wastage / increase water recovery. The permeate stream contains free carbon dioxide and is feed to a degasser column.

In thedegasser columnwater flows in the downward direction through the bed and Raschig rings. Air is introduced from the bottom of the degasser and it passes through the bed and raschig rings in the upward direction. The raschig ring bed ensures intimate contact between air and water. The carbon dioxide in water escapes from the top of the degasser along with air. The water from degasser tower is collected in degasser sump tank. The degasified water will be pumped in product water storage tank through degasified permeate transfer pump.Process Description : DM PlantDemineralization process is used when the dissolved solids are to be almost completely removed from water. A two bed DM plant consists of a cation exchanger and anion exchanger. The cation exchanger contains strongly acidic cation exchanger resins in "H+" form. When filtered water is passed through the cation exchanger, the resin retains calcium, magnesium, and sodium ions and gives an equal number of hydrogen ions to the water.

The reactions are :

R H+ + Ca2+ =======> R Ca + H+

R H+ + Mg2+ =======> R Mg + H+

R H+ + Na+ =======> R Na + H+

When the resin is exhausted it is regenerated with hydrochloric acid or sulfuric acid.

The reactions are :

R Ca + HCl =======> R H+ + CaCl2

R Mg + HCl =======> R H+ + MgCl2

R Na + HCl =======> R H+ + NaCl

Thus the water, which comes out of the cation exchanger is slightly acidic as the mineral salts are converted to respective mineral acids.

When water passes through cation exchanger the Alkalinity gets converted into carbonic acid. The reactions are as follows :

R-H + NaHCO3 =======> R-Na + H2CO3

R-H + Ca (HCO3)2 =======> R-Ca +H2CO3

R-H + Mg (HCO3)2 =======> R-Na + H2CO3The water coming out from the cation exchenger is acidic and it contains HCL corresponding to the Chlorides present in the raw water, H2SO4 corresponding sulphate in the raw water and carbonic acid corresponding to bicarbonate in the raw water. The carbonic acid is quite unstable and breaks into carbandioxide and water.H2CO3 =======> H2O + CO2

This CO2 can be easily removed by means of degasser. In the degasser water flow in the downward direction through the bed of packed Rasching ring. Air is introduced in the bottom of the degasser and it passes through the bed and rasching ring in the upward direction. The rasching bed ensures intimate contact between the water and the air. The air scrub in the water is free of carbon dioxide escape from the top of the degasser along with the air.

The water from the degasser tower is collected in the Degasser Sump Tank. It is then transfer to the Strong Base Anion unit through a degasser transfer pump.

The anion exchanger contains strong base anion exchange resin in Hydroxyl (OH) form. In the anion exchanger the resin removes anions like chlorides, sulfates, bicarbonates, etc. and equal number of hydroxyl ions are given to water.

The reactions are as under :

R OH- + Cl- =======> R Cl + OH-

R OH- + SO42- =======> R SO4 + OH-

R OH- + HCO3- =======> R HCO3 + OH-

When the resin is exhausted it is regenerated with a dilute solution of sodium hydroxide.

The reactions are as under :

R Cl- + NaOH =======> R OH + NaCl

R SO42- + NaOH =======> R OH + Na2SO4

R HCO3-+ NaOH =======> R OH + NaHCO3

The water from the anion exchanger is passed through a Cation Polisher Unit. It acts as a Polisher and give acidic water as per user requirement. The function of Cation Polisher is same as Strong Acid Cation ExchangerElectrical conductivity is used for expressing the purity of de-mineralized water. Conductivity is proportional to the residual ionized solids in the water. Low conductance indicates water of high purity, and typical Cation polished de mineralized water has a conductivity of less than 5 mS / cm. All de-mineralizers are provided with a conductivity meter for measuring the conductivity thereby indicating the purity of the treated water.

DegasifierIntroductionIn waterdemineralisation, a degasifier, or degasser, is often used to remove dissolved carbon dioxide after cation exchange. The most common degassers are of the so-calledforced draftoratmospherictype. One is represented below:

A forced draft degasifierPrinciple and detailsAfter cation exchange, the bicarbonate and carbonate (if any) ions are converted to carbonic acid, or carbon dioxide. CO2is soluble in water (see graph below), but it tends to escape into the air, much as it does in a glass of Coca-Cola when you stir it. Using a degasser to remove CO2reduces the ionic load on the strong base anion resin, and the consumption of caustic soda is thus lower.To be effective, the degasifier must be placedafter the cation exchange column. Before cation exchange, the water is containing bicarbonate. After it, the cations in water (Ca++, Mg++and Na+principally) are converted to H+ions, which combine with the HCO3bicarbonate anions to produce carbonic acid. The reaction details are shown in the page aboutprocesses, under demineralisation.In practice, the water coming out of the cation exchange unit is introduced into a column where it is sprinkled over a bed of filling material, often polypropylene shaped as saddles to leave a maximum volume of voids in the bed. Air is introduced at the bottom of the column by a blower, and escapes at the top, loaded with carbon dioxide from the water.The solubility of CO2in pure water is high: about 1.5 g/L or more than 30 meq/L at 25C and atmospheric pressure (see graph). When you stir the water and divide it into small droplets in an atmospheric degasifier and blow air through the "rain", the gas tends to move into the air because the partial pressure of CO2in air is much below the equilibrium pressure. The residual CO2after an atmospheric degasifier is 0.20 to 0.25 meq/L (typically 10 mg/L as CO2. Therefore such degassers are used when the bicarbonate concentration plus free carbon dioxide in the feed water to separate column demineralisation systems is at least 0.6 to 0.8 meq/L.The forced draft degasifiers are the most common in industrial water treatment, although there are other types of degasifiers, e.g. Thermal degassers, allowing to strip oxygen as well as carbon dioxide, Vacuum degassers, operating under a vacuum of 1 to 5 kPa for the removal of oxygen Membrane degassers, interesting in view of their small sizeFor RO permeates with low pH and high free CO2and for small demineralisation systems, membrane degasifiers can be used: