TABLE OF CONTENTS Once the resin volume is known, vessel sizes can be calculated. These sizes are not only dependent upon the service rate required but also include such factors as backwashing, regeneration, and good hydraulic design.
| (5.10) |  |
The volume of SAC resin (capacity 15.8 kgr/ft 3) needed to treat this quantity of water is 71 ft 3. Most resin suppliers recommend that a safety factor of 0.85 to 0.9 be incorporated into resin volume design. Using a 0.9 factor, the final design volume becomes:
| (5.11) |  |
A 2 GPM/ft 3 volumetric flow rate as suggested in Table 5-3 gives a bed depth of 48 inches with a tank diameter of 5 feet. This is within good design procedures.
| Guidelines for Good Hydraulic Performance of Ion Exchangers | |
|---|---|
| Parameter | Range of Value |
| Volumetric flow rate (gpm/ft 3) | 0.25 to 5 |
| Cross-sectional flow rate (gpm/ft 3) | 4 to 12 |
| Pressure drop per foot of resin (psi/ft.) [*] | 0.1 to 1.5 |
| Minimum bed depth (inches) [**] | 30 |
| [*]Pressure drop is determined by cross- sectional flow rate and water temperature. Values shown are for 4 10 gpm per sq. ft. flow rates and a temperature range of 40 F to 100 F. [**]The book Practical Principles of IonExchange Water Treatment (see Bibliography) recommends 9 feet as a maximum practical bed depth. |
Calculations for the SBA resin are similar. The capacity for the resin was determined to be 13.8 kgr/ft 3. (Anion resins usually have less capacity than...
