Softener Calculation.docx 2u4nj

Softener Calculation Step1 :- Get the water analysis. See that all analysis is ions are given as ppm CaCO3. You can not add mg/l as ions and ppm as CaCO3. All ions should be in the same unit. If not in the same unit ,first convert all ions to ppm CaCO3 and then feed in the analysis shown below Water Analysis Cations as CaCO3 Ca Mg Na K Fe

Anions as CaCO3 HCO3 190 CO3 0 OH 0 Cl 60 SO4 30 NO3 5 Total cation 280 Total anion 280 Total Hardness as CaCO3( Ca+Mg) 110 SiO2 10 %N a/TC 0.5 CO2 5 T.AlkalinityasCaCO3(HCO3+CO3+OH) 190 EMA as CaCO3 (Cl+SO4+NO3) 95 %alkalinity/TC 67.85714 %weak acids/T.A 5.357143 %Cl 21.42857 %SiO2/TA 1.785714 85 25 140 30

Step 2 :- Decide on a Hardness leakage in the effluent and select the regeneration level Step3 :- From the regeneration level select the Exchange capacity from the graph or Table . Using correction factor you get the actual operation capacity Step 4 :- Calculate the OBR required . OBR – output between regeneration is Service flow rate *time the unit runs. There are many instances when OBR is given by the customer but the flow rate is not known then OBR/time gives the flow (M3/Hr) If you know the flow feed in the flow and service cycle duration otherwise feed the OBR . Step 5 :-Calculate Resin Quantity Resin quantity = Hardness load (ppm CaCO3)*OBR/ Operating capacity Step3 :- Decide on thevolumetric flow rate (M3/Hr) Hourly flow rate 10 M3/Hr Service Cycle hours 24 hours Total OBR between Regeneration 240 M3 Step4:- calculate resin quantity Resin quantity 471.43 liters Resin quantity 0.471 M3

10 12 120 235.71 0.236

Step6:- Finding the Area and diameter of the softener unit Area = Volume/Height ( height is here is the Bed Depth ) Since we know the volume of resin and we select 1.2 M as bed depth (Bed depth according to Resin manufacturer calculation should be between 750 mm to 2000mm .But for all practical purpose bed depth is kept between 1 to 1.5. for residential purpose smaller bed depth may be used)

Area = Volume of Resin / Bed depth Area = D2/4 Where  =3.14 Therefore /4 =3.14/4=0.785. Area=0.785D2. Or D2 = sqrt (Area/0.785). Step5 :- Calculating Softener Dimension Bed depth 1 Meter Area 0.47 Diameter 0.800 M Diameter 800 mm Area 0.5024 M2 Actual Bed depth 0.94 M

1 0.24 0.500 500.0 0.19625 1.201

M mm M2 M

Step 7 :- Calculate the Salt Quantity required for Regeneration Salt quantity in Kgs = Resin volume in M3 * regeneration Level gm/L Step 6:_Calculating salt quantity Regeneration Level Salt required

160 gm/L 75.43 Kgs

160 37.71

Step 8 :- Check linear and space Velocity Check linear velocity. The value should be in the range of 10 – 25 M3/hr/M2. A slightly lower value can be tolerated if the water is clear and slightly more if small increase in the hardness leakage in the effluent can be tolerated Linear Velocity = Flow /Area If the Linear velocity is very high, reduce flow . For a flow of 10 M3/Hr and hardness load of 110 ppm CaCO3 the linear velocity is very for a OBR of 120 M3 and service Cycle of 12 Hours .Increase service cycle this will reduce the flow rate. There are many instances where the Linear velocity is taken as a starting point for calculation ( Click Here) Taking the limit of 25 M3/Hr /M2 as Maximum velocity we can calculate the actual number of regeneration per Day. Linear Velocity = Flow /Area Number of regeneration per day = Derived Linear velocity /Maximum Linear velocity Say calculated linear velocity is 20 then Number of regeneration per day =20/25 =0.8 i.e.1 Now let us consider that calculated linear velocity is 60 Number of regeneration per day =58/25 =2.32 i.e.2 Similarly if calculated linear velocity is 75 than Number of regeneration per day =78/25 =3 .12 i.e.3 Actual Flow = (Actual Linear Velocity /N)* Actual area Step 9 Check space velocity Space velocity = Actual flowM3/Hr / calculated amount of resin in M3 Step10 Finding the correct OBR = OBR per Day in M3/Number of regeneration

Step 7:- Check Linear and Space velocity Linear Velocity 19.90 Number of regeneration 1 Flow per Hour 9.4 Actual Linear velocity 18.71 Space Velocity 19.94 Step 8 :- find OBR per regeneration 240

M3/Hr Per day M3/Hr M3/Hr/M2 M3/Hr/M3 M3

50.96 2 6 30.57 25.45 60

M3/Hr Per day M3/Hr M3/Hr/M2 M3/Hr/M3 M3

Step 11 :- Calculate regenrant flow time and flow . At 3M3/hr/M3 the regenrant flow in M3/hr is resin Quantity X Velocity. Flow in M3/hr = 3 X M3 of resin Volume in M3 Time = ------------------Flow in M3/hr There are times when the regenrant time is assumed to be 30 minutes minimum and chemical injection flow rate is calculated on this basis. Volume in M3 Volume in M3 3 Regenrant flow (M /hr) = --------------------------- = --------------------------. Time in hours 0.5 Hours Step12:- Calculate Rinse timing :- Fast rinse in normally recommended between 12 – 16 M3/hr/M3 velocity. Let us be conservative and use 12 M3/hr/M3 for calculation purpose which is normally taken by all designers. Fast Rinse flow = 12 X Resin Qty Volume of water per M3 of Resin Fast Rinse period (minutes) = -------------------------------------------Rinse Flow 3 Rinse volume is considered to be 5M /M3 of resin. (5 bed volumes) In this case = 5 X 1.071 = 5.355. 5* Resin Volume Final Rinse period = ----------------------- X 60 = Time in Minutes Rinse Flow rate Step13 :- There are many instances when Slow rinse is done after Chemical injection . This is done to flush out the excess chemical. The flow rate is same as that of injection flow rate.

TECHNICAL DATA SHEET Parameters Diameter of Vessel Diameter of vessel Area of Vessel Bed Depth Unit HOS Resin Volume Salt required Hardness in influent Output between Regeneration(OBR) Minimum Treatment Flow Maximum Treatment flow Normal flow M3/Hr Period between regeneration Regeneration flow Slow Rinse Fast Rinse Minimum pressure Maximum pressure Backwash Flow Backwash period

Unit Meter mm Sq. meter M2. Meter Meter Cubic Meter (M3) Kgs As CaCO3 M3 M3/Hr M3/Hr M3/Hr Hours M3/Hr M3/Hr M3/Hr Kg/cm2 Kg/cm2 M3/Hr minutes

Values

Note 1 There is no Backwash if the unit is upflow. 2 The direction of salt injection is from top to bottom in upflow units. 3 Minimum injection is taken as 30 minutes and regeneration flow rate is calculated on this basis. Check Step no 11.