Non-agglomerating mixed bed ion exchangers

a technology of ion exchangers and mixed beds, which is applied in the direction of ion exchangers, ion exchange columns/bed processes, chemistry apparatus and processes, etc., can solve the problems of poor flow behaviour, unsatisfactory performance of such mixed beds, and agglomeration,

Inactive Publication Date: 2008-01-10
LANXESS DEUTDCHLAND GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0008]Surprisingly, the sole treatment of the anion exchange component according to the invention produces a non-agglomerating readily separable mixed bed having excellent desalting performance.
[0010]These condensates are generally in the form of their alkali metal, alkaline earth metal or ammonium salts and are accompanied by “neutral salts” from synthesis-specific neutralization reactions. The use of these condensates can, but need not, proceed in the form of their low-salt formulations, the production of which is described, for example, in EP-A 0 816 406. Quite in contrast, salt additions can obviously improve the take-up behaviour of the condensates, which is demonstrated in measurably improved desalting performance (Example 5, FIG. 3). In a preferred embodiment, therefore salt is added to the anion exchange component, particularly preferably alkaline earth metal salts. Use is made particularly preferably of calcium chloride.

Problems solved by technology

Surface interactions between the cationic and anionic components of the mixture lead to the formation of agglomerates (“clumping”) and thereby to poor flow behaviour.
Furthermore, the performance of such mixed beds is unsatisfactory.
In addition the agglomeration prevents effective regeneration of the ion exchange resins for which the mixture must be fractionated as completely as possible into its components.
The above processes all have the disadvantage that the polyvinylaromatic acids or ammonium compounds are only accessible in the suitable molar mass range with relative difficulty and that to achieve good separability in the mixed bed both charge components must be treated.

Method used

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  • Non-agglomerating mixed bed ion exchangers
  • Non-agglomerating mixed bed ion exchangers

Examples

Experimental program
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Effect test

example 1

[0026]The anion exchange resin to be treated (LEWATIT® MonoPlus M 500) was charged in a glass beaker with the specified amount of condensate as a 0.1% strength solution. The mixture was stirred for 20 min and then allowed to stand for a further 10 min. Thereafter it was dewatered and washed with 2 BV (bed volumes) of deionized water.

[0027]50 ml of the anion exchange resin thus treated were shaken under water on a vibrating bench to constant volume and mixed with the same volume (shaken under water) of a strongly acidic cation exchanger (LEWATIT® MonoPlus S 200) by stirring in a glass beaker. Subsequently the mixture was shaken under water on the vibrating bench. The volume of the mixture was determined. Results with different condensates in different application rates may be found in Table 1.

example 2

[0028]The anion exchange resin to be treated (LEWATIT® MonoPlus M 500) was admixed in a glass beaker with 1.5 g / (litre of resin) of the NSS condensate 2, dissolved in demineralized water, with stirring. The mixture was then allowed to stand for 10 min. Thereafter it was dewatered and washed with 2 BV of deionized water. Regeneration proceeds via treatment with 300 g of NaOH 100% / l of resin as 5% strength solution which was passed through the bed.

[0029]250 ml of the anion exchange resin thus treated were shaken under water on a vibrating bench to constant volume and mixed with 160 ml (shaken under water) of a strongly acidic cation exchanger (LEWATIT® MonoPlus S 200) by stirring in a glass beaker. Subsequently the mixture was transferred to an exchange column and charged with 10 BV of drinking water.

[0030]By water flowing in at the column bottom, the bed was then extended for the regeneration to about three times its height. After approximately 2 min the flow of the influent water wa...

example 3

[0032]The anion exchange resin to be treated (LEWATIT® MonoPlus MP 500) was charged in a glass beaker with 1.5 g / (litre of resin) of naphthalenesulphonic acid condensate 1 as 0.1% strength solution or with 1.25 g / (litre of resin) of sulphonated polystyrene (Versa® TL 130). The mixture was stirred for 20 min and then allowed to stand for a further 10 min. Thereafter it was dewatered and washed with 10 BV of deionized water.

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Abstract

The invention relates to a process for producing non-agglomerating mixed bed ion exchangers or mixed bed components.

Description

[0001]The invention relates to a process for producing non-agglomerating mixed bed ion exchanges or mixed bed components.BACKGROUND OF THE INVENTION[0002]The use of mixed bed ion exchangers is prior art in the desalting of aqueous solutions. Surface interactions between the cationic and anionic components of the mixture lead to the formation of agglomerates (“clumping”) and thereby to poor flow behaviour. Furthermore, the performance of such mixed beds is unsatisfactory. In addition the agglomeration prevents effective regeneration of the ion exchange resins for which the mixture must be fractionated as completely as possible into its components.[0003]To prevent the unwanted clumping in mixed beds, diverse methods have been described such as, for example a) the treatment with water-insoluble ion exchange particles in U.S. Pat. No. 4,347,328 where high amounts used and high washwater volumes are required in order to remove excess ion exchange particles again or else b) the treatment ...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): C08J5/20
CPCB01J41/12B01J47/04B01J47/006B01J47/016
InventorZARGES, WOLFGANGHILGER, STEFANVANHOORNE, PIERREWEDEMEYER, HANS-JURGEN
OwnerLANXESS DEUTDCHLAND GMBH