DD257397A1 - BINDER FOR MOLECULAR SIEVE I - Google Patents

Abstract

The invention relates to binders for molecular sieves. It is the object of the invention to substantially improve the mechanical properties of molecular sieves pressed with binders and their release properties. The object is to use as binder such mixtures whose mineralogical composition ensures that after pressing and granulation of the molecular sieve a largely unobstructed diffusion of Adsorptivmolekuelen to and from the active sites of the zeolite is possible. The task is solved by the use of slurred clays, preferably Friedlaender Blautons or Brandiser Tons.

Description

Field of application of the invention

The invention relates to binders for molecular sieves, which lead to an improvement of the mechanical and adsorptive properties of the latter.

Characteristic of the known technical solutions

It is known to produce molecular sieves on an industrial scale such that the actually adsorbing component, the zeolite, is mixed with a binder and shaped into granules by conventional technology. The binder serves to improve the mechanical properties of the molecular sieves, in particular its abrasion resistance and compressive strength. The binders used are natural clays which are dried and ground immediately after degradation and added to the molecular sieve, which may have been subjected to a wide variety of pretreatment methods, in particular cation exchange processes.

The use of natural clays as a binder has some disadvantages. Thus, the adsorptive and mechanical properties of the resulting molecular sieve granules are different when using different clays, which is unsatisfactory for the technical user, because it ensures no quality consistency. The cause of the quality fluctuations of the molecular sieves lies in the different, due to the particular geological conditions related mineralogical composition of the clays.

Object of the invention

The invention aims to substantially improve the mechanical properties of the binder-pressed molecular sieves and their release properties, and to minimize quality variations in the binder composition.

Explanation of the essence of the invention

The invention has the object to use as binders such mixtures whose mineralogical composition ensures that after pressing and granulation of the molecular sieve, a largely unobstructed diffusion of Adsorptivmolekülen to and from the active sites of the zeolite is possible.

The invention is based on the finding that the clays to be used as binders have a different mineral composition whose most extensive separation into individual constituents is possible by sedimentation. The object is achieved in that slurried clays are used as binders in the production of molecular sieve granules.

By the clays of the clays, the desired swellable phyllosilicates accumulate, while the non-swellable constituents, such as quartz, feldspar, Fe ₂ Oe, etc., settle as soil bodies. The sludge times must be varied and optimized according to the mineralogical composition and the intended use. They are preferably within the range of 5 to 30 minutes. The enriched in swellable phyllosilicates part (slurred clay) is added to the molecular sieve as a binder in the mass ratio 80:20 to 60:40. The invention will be explained in more detail below with reference to exemplary embodiments without being limited thereto.

+ Bentonite (5) 8th 28 + Bentonite (10) 11 34 + Bentonite (20) 20 41 + Bentonite (30) 18 45

embodiments

Example 1: ·.

A sample of bentonite is slurried to a 1% suspension. After a slurry time of 5.10, 20 and 30 minutes, the suspension is separated from the sediment. The solids in the suspension are centrifuged off and dried.

The slurried bentonite thus obtained is mixed with a molecular sieve in the mass ratio of 80 to 20 and pressed.

Upon activation and annealing of the resulting rodules, compressive strength and abrasion as well as the separation factor for the propane / propene separation are determined.

Table: Mgo ^ Nao.a-A zeolite-slurried bentonite (slurry times in minutes) Sample Release factor Compressive strength Abrasion

(MPa) (%)

10 7 4 3

An optimum of the mechanical and adsorptive properties of the granules is achieved with slurried bentonite as binder after a slurry time of 20 minutes.

Example 2:

According to Example 1 Friedländer blue clay is treated at slurry times of 10,20,30 and 60 minutes and used accordingly as a binder.

Table: Mgo.aNao.eA-Zeolite-milled Friedländer blue clay (slurry times in minutes) Sample Release factor Compressive Strength Abrasion (MPa) (%)

3,

An optimum of the mechanical and adsorptive properties of the granules is achieved with slurried Friedländer blue clay as binder after a Schlämmzeit of 30 minutes.

Example 3:

According to Example 1 Brandiser clay is treated at Schlämmzeiten of 30,60,180,360 and 1440 minutes and used accordingly as a binder. From the granules obtained, the loading molecules Propen per large cavity is determined.

Table: Na4A zeolite-slurried Brandiser clay (slurry times in minutes) Sample molecules of propene per large cavity

MgO, Na _{2 o,} sA 33 29 + Blue tone (10) 29 34 + Blue tone (20) 70 23 + Blue tone (30) 38 30 + Blue tone (60)

Na4A 0.12 + Brandiser clay (30) 0.16 + Brandiser clay (60) 0.26 + BrandiserTon (360) 0.07 + Brandiser clay (1440)

A maximum of the adsorptive properties is achieved with slaked Brandiser clay, as a binder, after a slurry time of 360 minutes.

Claims (5)

1. binders for molecular sieves, characterized in that naturally occurring clays are pressed with high proportion of swellable phyllosilicates to molecular sieves. 2. Binder for molecular sieves according to item 1, characterized in that slurried natural clays are used. " 3. Binder for molecular sieves according to item 1, characterized in that slurried Friedländer blue clay is used. 4. Binder for molecular sieves according to item 1, characterized in that slurried Brandiser clay is used. 5. Binder for molecular sieves according to item 1 to 4, characterized in that the mass ratio of the binder to the zeolite of 80 to 20 to 60 to 40.