| 摘要 |
1,261,042. Ion exchange. CRANE CO. 22 Jan., 1969 [23 Jan., 1968], No. 3627/69. Heading B1J. Ion exchange apparatus containing a fixed bed of ion exchange material during at least service flow is operated according to a method which is designed to reduce leakage from the ion exchange material during service flow of ions which have been exchanged on to the ion exchange material during previous service flow but which have not been removed from bed of ion exchange material, after regeneration thereof; such method comprises the steps of (a) recycling a plurality of time through the bed of ion exchange material, after regeration thereof and in the direction of service flow, a composition which removes by mass action from the ion exchange material at the. service flow exit end of the bed the ions liable to such leakage and which relocates these ions on the ion exchange material at the service flow inlet end of the bed and (b) thereafter rinsing the bed to remove the composition which has been recycled therethrough. The composition, which may be recycled through the bed at a temperature exceeding the temperature of normal service flow, may be provided by dilution of the regenerant used for regeneration of the ion exchange material of the bed. As exemplified, ion exchange apparatus is operated in a manner such that service flow and rinsing after recycling each is effected by downward flow through a bed of ion exchange material and regeneration is effected either by downward flow through the bed, see Figure 1 (not shown) or by upward flow through the bed, the regenerant being removed from the bed at a level below the top of the bed, see Figure 2 (not shown), the composition which is to be recycled being provided in each case by dilution of regenerant by the addition thereto of diluent water prior to the passage thereof through the bed. Reference also is made to various other modes of operation in respect of the direction of flow through the bed during service flow, regeneration and rinsing after recycling. |
