| 摘要 |
<p>Process and an installation for ion exchange treatment of water which requires pretreatment in a cationic resin bed to absorb ammonia followed by normal purificn. in a mixed resin bed is described. The installation comprises a single exchanger vessel contg. a cationic resin bed resting on top of a bed of mixed anionic and cationic resins. There is no mechanical sepn. between the two beds which have a horizontal interface. Water for treatment is passed down through the two beds. - For periodic regeneration of the resin. In the upper, cationic bed, this resin is sepd. and transferred hydraulically into a regeneration vessel, leaving the mixed bed resin in the exchanger vessel. Bed resin sepn. is effected by a series of water jet nozzles around the interior of the exchanger vessel in the plane of the interface. The nozzles deliver flat narrow, horizontal jets which drive the upper bed resin into the entry of a transfer pipe to the regeneration vessel. - Before returning the regenerated, upper bed resin to its place on top of the mixed bed, the latter bed is drained of all liq. so that its resin stays in position and does not mix with the upper bed resin. - The process is used to purify power station condensate for recycling. This requires treatment which reduces concns. of sodium and chlorine to as low as about 1.5 micro-ems per litre. To achieve such low sodium concn. a cationic pretreatment bed must absorb ammonia picked up from condenser leaks. The elimination of a separator grill between upper and lower resin beds simplifies construction and reduces both capital cost and maintenance expenses.</p> |
