DOWEX Ion Exchange Resins WATER CONDITIONING MANUAL

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Ion Exchange Resin Operational Information For packed-bed, counter-current regeneration systems, the procedure is the same as above with the following modifications: 1. The freeboard should be 5% of the total resin bed height, taking the volume of the resins in the most swollen form. For the strong base anion, this is the fully regenerated hydroxide form, and for the weak base anion, the exhausted form. 2. Before adding the weak base resin, add the floating inert resin on top of the strong base anion and then load the weak base resin on top. Reference Document: Tech Facts 177-01763 9.2.4 Loading Procedure for Regenerable Mixed-Bed Resins These procedures are specifically designed for equipment which is internally regenerated, with an interface collector between the cation and anion layers. 1. Fill vessel with sufficient water (approximately 1/3 vessel height) to allow settling and avoid resin damage. 2. Load cation resin to about 2 in. (5 cm) below final desired level. 3. Backwash cation at 5–6 gpm/ft 2 (12–15 m/h) for 30 min. 4. Settle and drain bed to 2–4 in. (5–10 cm) above resin surface and fill remaining cation resins up to the level of the central collector (if in the hydrogen form) or 1–2 in. (3–5 cm) below if in the sodium form. Carry out a second backwash for 10 min and settle. Ensure that the resin surface is even and at the correct level. 5. With 3 ft (1 m) of water above the cation resin, load anion resin. Backwash at 2 gpm/ft 2 (5 m/h) for 5 min. 6. If anion resin is in the chloride form or cation resin is in the sodium form, carry out double regeneration on both resin components. 7. Rinse resins with flow from top and bottom, with removal of rinse water through the central collector, for 30 min. 8. Reduce water level to about 2 in. (5 cm) above the resin bed and air mix for 15–20 min. Reference Document: Tech Facts 177-01757 9.2.5 Start-up Operation Start the run and monitor rinse down until the specified conductivity, silica, and TOC (if necessary) are achieved. For regenerable mixed bed, resin clumping may still be present if the required water quality is not reached. To eliminate this, the mixed bed should be run for a minimum of 5 h and then a further 15-min air mix should be carried out at the end of the service run before backwashing to optimize resin mixing. Do not try to separate new or freshly regenerated resins. 9.3 Resin Sampling A representative sample of ion exchange resins in vessels is necessary for accurate resin analyses. Ideally, a sample is taken throughout the vessel and mixed well to represent the overall bed. Several devices have been developed and used over the years to get such a core sample (Figure 20). DOWEX Ion Exchange Resins 48 Water Conditioning Manual
Ion Exchange Resin Operational Information Drained bed level Figure 20. Examples of devices for obtaining a core sample. USING GRAIN THIEF Fluidized bed level USING SIPHON HOSE Slow backwash An example procedure to obtain a representative sample of a resin bed from the top of the bed to the bottom with minimum equipment expense is as follows: 1. Build the device as shown in Figure 21. It is important that the lower stopper be rounded or it will not seat properly. A rubber ball may be substituted in place of the stopper, but its diameter must be larger than the pipe diameter. Other required equipment: • Clean 2–3 gal (approximately 10-L) plastic bucket • Plastic 1 qt (1-L) sample jars • Plastic storage bags for secondary leak containment Figure 21. Example of device for obtaining a sample from top to bottom of a resin bed. DOWEX Ion Exchange Resins 49 Water Conditioning Manual
Page 1 and 2: Dow Liquid Separations DOWEX Ion Ex
Page 3 and 4: TABLE OF CONTENTS 1 Introduction to
Page 5 and 6: TABLE OF TABLES Table 1. Terms comm
Page 7 and 8: Introduction to Ion Exchange 1 INTR
Page 9 and 10: Terms, Acronyms, And Abbreviations
Page 19 and 20: Sodium Cycle Ion Exchange Process (
Page 27 and 28: Brackish Water Softening Using H2SO
Page 29 and 30: Brackish Water Softening Resin oper
Page 31 and 32: Dealkalization: Salt Splitting Proc
Page 33 and 34: Dealkalization: Weak Acid Cation Re
Page 35 and 36: Dealkalization: Weak Acid Cation Re
Page 37 and 38: Demineralization (Deionization) Pro
Page 39 and 40: Demineralization (Deionization) Pro
Page 41 and 42: The UPCORE Counter-Current Regenera
Page 47: Ion Exchange Resin Operational Info
Page 51 and 52: Ion Exchange Resin Operational Info
Page 57 and 58: Ion Exchange Cleaning Procedures 10
Page 59 and 60: Ion Exchange Cleaning Procedures Re
Page 61 and 62: Ion Exchange Cleaning Procedures 10
Page 63 and 64: Ion Exchange Cleaning Procedures Ta
Page 65 and 66: Designing an Ion Exchange system fr
Page 67 and 68: Designing an Ion Exchange system As
Page 69 and 70: Designing an Ion Exchange system 11
Page 71 and 72: Useful Graphs, Tables, and Other In
Page 91 and 92: Index 14 INDEX A Abbreviations · 9
Page 93: Dow Liquid Separations Offices. For

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