1. Ion-exchange process (softener plant) Water passes through bed of natural zeolite of synthetic resin to remove hardness Calcium (Ca) and magnesium (Mg) replaced with sodium (Na) ions Does not reduce TDS External Water Treatment 1

2. Softener Plant 2

3. DM System 3

4. 4

5. Osmosis Solutions of differing concentrations Separated by a semi-permeable membrane Water moves to the higher concentration External Water Treatment 5

6. Reversed Osmosis (RO) Higher concentrated liquid pressurized Water moves in reversed direction External Water Treatment 6

7. RO System 7

8. 8

9. Electrodialysis 9

10. Electrodialysis for Water Treatment 10

11. External Water Treatment& Internal Water Conditioning 11

12. Prevention of internal scale by forming deposits in sludge shape Injection of chemicals Different chemicals for different water impurities Conditions: For low amounts of feed water impurities For low pressure boilers, TDS content has higher limits Internal treatment alone not recommended Internal Water Conditioning 12

13. Scale control Injection of chemical additives Minerals (Na 2 CO 3, Na 3 PO 4, Na 2 HPO 4, NaH 2 PO 4, (NaPO 3 ) 6,…) Organics (Chelants, Lignins, Starches, Tannins, …) Minerals + Organics Chelants (NTA, EDTA, …) Internal Water Conditioning 13

14. De-aeration Removal of various dissolved gases from water (O 2, CO 2, …) These gases are corrosive. De-aerator can decrease amount of dissolved gases in water. External Water Treatment 14

15. External Water Treatment Steam Storage Section De-aerated Boiler Feed Water Scrubber Section (Trays) Boiler Feed Water Vent Spray Nozzles O 2 and CO 2 removed by heating feed water Economical treatment process Vacuum type can reduce O 2 to 0.02 mg/L Pressure type can reduce O 2 to 0.005 mg/L Mechanical de-aeration 15

16. Removal of Dissolved Oxygen Trace Pitting Corrosion control Sodium sulphite: Increases TDS: increased blow down Hydrazine Does not increase TDS: used in high pressure boilers 16

17. Mechanical (Boiler design) High level of water in drums Deficiency on separator operation Sudden increasing boiler load (reduction of pressure) Chemical High TDS High alkalinity Oil and organic impurities Causes of Carry Over 17

18. Corrosion & scale control Acid (H + ) attack Adjustment of water pH based on manufacturer recommendation Water Conditioning 18

19. Caustic embrittlement control Adjustment of water NaNO 3 /NaOH ratio depending to boiler pressure (According to manufacturer recommendation) Water Conditioning 19

20. Controls TDS of the boiler water Boiler sludge conditioning Blows off water and replaces it with feed water Conductivity measured as indication of TDS levels Boiler Blow Down 20

21. Benefits Lower pretreatment costs Reduced maintenance downtime Increased boiler life Lower consumption of chemicals Boiler Blow Down 21

22. Types of blow down Batch (Periodic) Manually operated valve reduces TDS Large short-term increases in feed water Substantial heat loss Continuous Ensures constant TDS and steam purity Heat lost can be recovered Common in high-pressure boilers Boiler Blow Down 22

23. Application of proper external treatment Application of accurate internal conditioning Amounts of used chemical Amounts of produced wastes/sludge Amounts of wasted water (blow down) Cost of monitoring & Control Economy of water treatment/conditioning Recirculation of used steam Water/Chemical Economics / Optimization 23

24. THANKS FOR YOUR ATTENTION