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Purpose: To lay down operating procedure for regeneration of demineralized water plant.
Scope: This procedure is applicable for …………….
Responsibility: Production Chemist
To supervise the activity
EQUIPMENTS USED:
1. Portable Deioniser
a) For anions & cations (Model CA-60 U)
b) For Mixed bed (Model MB-25)
PROCEDURE:
A. Regeneration of cations:
1. Acid Preparation:
a) Take 22 ltr of DM water in an anticorrosive container .
b) Add 10 ltr. HCL into it & stir well.
c) Pour this solution into the regenerate container.
2. Acid injection:
a) Open valve B fully.
b) Open & adjust raw water supply valve to get a flow of 1.25 ltr/min.
3. Acid Downflow Rinse:
a) Pour 16 ltr. of DM water into the regenerate container & connect to raw water supply valve. Open B fully.
b) Open & adjust raw water supply valve to give a flow of 2.5 liter/min.
c) Repeat the step a) for another 16 ltr. of DM water.
4. Acid up Rinse:
a) Reconnect raw water inlet tube to the raw water supply valve.
b) Close the diaphragm valve.
c) Open valve C & D. Open & adjust raw water supply valve to give a Flow of 5.0 liter/ minute.
d) After 20 min., close valve C & D & raw water supply valve.
B. Regeneration of anions:
1. Soda preparation:
a) Take 32 ltr. of DM water in an anticorrosive container.
b) Add 2.4 kg of caustic soda, stir to dissolve & allow to cool.
2. Soda injection;
a) Take 16 ltr. of soda solution in a regenerate container & Connect the tubing at the top to raw water supply valve.
b) Close the diaphragm valve.
c) Open valve A&D. Open & adjust raw water supply valve to give flow rate of 1.25liter/minute.
d) Repeat the procedure for another 16 ltr. of soda solution.
3. Caustic Rinse:
a) Pour 16 liter of demineralized water into regenerate container after ensuring that it has thoroughly drained.
b) open valve A & D. Open raw water supply valve & adjust to give a flow of 2.5 liter/minute.
4. Final rinse:
a) Open raw water supply valve & diaphragm valve.
b) Open valve C & adjust to give a flow of 10 liter/ minute.
c) Maintain the flow till conductivity falls to an acceptable limit.
Regeneration of Mixed Bed
1. Backwash :
a) Open valve D fully.
b) Open & adjust valve B to get the backwash flow of 4.5 ltr./min.
c) Maintain the flow for 10 min.
2. Settle:
Close all valves for 10 min.
3. Soda injection:
a) Prepare a solution of 0.750 kg caustic soda in 12 ltr of DM water & pour into the regenerate container.
b) Open valve E fully.
c) Adjust valve G to maintain the flow within 10 min.
d) Close E & G.
4. Soda Rinse:
a) Open valve E fully.
b) Open & adjust valve G such that the rinse water is emptied in 10 minutes..
c) Close E & G.
5. Acid injection:
a) Prepare a solution of 1.8 ltr. HCl in 7.5 ltr. D.M.water.
b) Open F fully.
c) Adjust valve H such that solution flows out in 10 minutes.
6. Acid Rinse:
a) Flush out excess acid with 7.5 ltr. DM water.
b) Open F fully & adjust H such that solution flows out in 10 mins.
c) Close F&H.
7. Air-mix:
a) Open D & H fully.
b) Connect PVC tube to the air blower & switch it on.
c) Carry out air mix for 10 minute at minimum pressure of 1 kg/cm².
8. Settle after Air-mix
a) Disconnect air inlet tube from air blower.
b) Open valves A,C & raw water supply valve to give maximum possible flow.
c) Close D & H.
d) Switch off the air blower.
e) After 1 minute, open valve D to release any air that may be entrapped inside the unit.
9. Final rinse:
a) Close valve D & adjust raw water supply valve to maintain the flow of 4.5 ltr./min.
b) Continue rinse for 10 min.
c) Switch on the conductivity indicator.
d) If conductivity does not fall below 1 microsiemen /cm, repeat step7,8&9.
e) Check the pH of the water as it should be in the range of 5.5 to 7.5.
f) If it is found within limits, connect the raw water supply & collect the final water for use.
10. Sampling:
a) Intimate the QA Dept. for sampling for chemical & microbiological Testing.
Precautions:
1. The regeneration procedure must be continuous.
2. While carrying out steps 3,4,5& 6 of mixed bed regeneration , never allow the regenerate container to drain fully. Close the specified valves to prevent air locks.
3. Place the air blower at a height above the top of unit to avoid chance of water flowing into the blower.
4. Avoid contact of acid & alkali with eyes, skin & clothing.
5. Always wear goggles & gloves while handling the chemicals.
6. When diluting acids, always add acids to water slowly & carefully.
