Mixed-type effect filters are used for elimination of hydrated salts from processed water.
TECHNOLOGICAL PROCESS SCHEME
TECHNOLOGICAL PROCESS DESCRIPTION
The working principle of the mixed-type effect filter is based on water filtration through grain material (cationite and anionite mixture). Monodispersed ionites having small dispersion in gravimetric contents are used to load mixed-type effect filters
Cationite, with larger grains than anionite grains, is used to loosen and further reduce the water supply. Cationite settles at the bottom and the anionite layer locates to the top.
Mixed-type effect filters essentially differ from single-layer load units (cationite or anionite filters). Firstly, anionite and cationite are used in one and the same case. Both resins are mixed with compressed air flow immediately before utilization. Thus grains of different resins are located close to each other. Overall, this load works as an infinite number of anionite and cationite filters working successively.
Water purified with mixed-type effect filters has neutral medium and low salt content.
The working process of mixed-type effect filters consists of 3 main stages: filtration, loosening and regeneration.
Water is demineralized during filtration:
Separate regeneration of cationite and anionite by acid and alkali solutions when cationes or aniones passes over, respectively.
Loosening process is performed from bottom to top with separating cationite and anionite due to density difference. Cationite as the more compact material forms the bottom layer. Anionite as the lighter material forms the higher layer. The end of the cationite and anionite separation process can be visually observed in inspection windows.
Cationite and anionite are regenerated seperately. Cationite is regenerated with hydrochloric acid solution. Anionite is regenerated with sodium hydroxide solution. After regeneration layers are washed and mixed once again using compressed air.
Ionite regeneration can be performed either in a working mixed-type effect filter (mixed-type effect filter with internal regeneration) or in special regenerators. In the latter case, working filters where water is processed are called mixed-type effect filters with external regeneration. The ionite regeneration type predetermines the construction of a mixed-type effect filter.
In a mixed-type effect filter with internal regeneration, the acid solution is fed in through the bottom drainage unit and disposed through the intermediate distribution system. Simultaneously to prevent acid from getting into anionite demineralized water is passed through it from top downward disposing it also from intermediate collector. Washing of cationite with acid solution after regeneration is combined with anionite regeneration provided that alkali solution is fed in through top distribution unit located over the anionite layer and disposed through the intermediate distribution system. Demineralized water for washing cationite is supplied in the same way as acid solution (from the bottom upwards). Then the anionite is washed. Afterwards ionites in the filter are mixed by compressed air and finally washed from regeneration products.
In a mixed-type effect filter with external regeneration using hydro-transferring (water flow) cationite and anionite mixture is transferred from the working filter into the first filter-regenerator where the mixture is separated for cationite and anionite. Then anionite using hydro-transferring is directed to the second filter-regenerator. Afterwards separate regeneration cationite and anionite are transported into the working filter, mixed by compressed air, additionally washed and included in the work.
The organization of external ionite regeneration excludes the entry of regeneration acid and alkali solutions into purified water.
- any productivity (customized)
- utilization of advanced materials
- easy maintenance and high work reliability