Adsorbent granulate and method for the manufacture thereof

Abstract

The invention relates to a X-zeolite based adsorbent granulate with faujasite structure and a molar SiO 2 /Al 2 O 3 ratio of ≧2.1-2.5, wherein the granulate has an average transport pore diameter of >300 nm and a negligible fraction of meso-pores and wherein the mechanical properties of the granulate are at least the same as or better than the properties of an X-zeolite based granulate formed using an inert binder and the equilibrium adsorption capacities for water, CO 2 and nitrogen are identical to those of pure X-zeolite powder with a similar composition.

1 . An adsorption agent granulate based on zeolites, comprising: a faujasite structure, a molar SiO 2 /Al 2 O 3  ratio of ≧2.1-2.5, a mean transport pore diameter of >300 nm, wherein the transport pores include meso pores and macro pores and the meso-pore fraction is <10%, preferably <5% with mechanical properties which facilitate safe handling of the granulate an sufficient processability. 
     
     
         2 . The adsorption agent granulate according to  claim 1 , wherein the pressure resistance measured at a dried granulate with a diameter in a range of 1.6-2.5 mm is ≧30 N/ball. 
     
     
         3 . The adsorption agent granulate according to  claim 1 , wherein the static adsorption capacity in at least 96% of the value for a zeolite powder with the same structure and composition and the crystallinity of the zeolite portion determined through x-ray graphics is >85%. 
     
     
         4 . A method for producing an adsorption agent granulate according to  claim 1 , wherein a X-type zeolite with a molar SiO 2 /Al 2 O 3  ratio ≧2.1-2.5 provided as a dry powder, filter cake or slurry is mixed at a weight ratio of 1:1 to 1:5 with a thermally treated kaoline with a mean particle diameter in a range of ≦10 μm which may include ≦5 mass % non kaolinitic material, the mixture is then mixed with a mixture of sodium hydroxide and sodium silicate solution, the mixture is formed into a granulate the granulate is subjected to a drying process and subsequently hydrated with completely de-salinated water and treated with a sodium aluminate solution at temperatures in a range of 70° C.-90° C. over a time period of up to 24 hours, then the granulate thus treated is separated from the solution, washed, dried and tempered. 
     
     
         5 . A method according to  claim 4 , wherein the temperature for thermally treating the kaoline is in a range of 600° C. to 850° C. 
     
     
         6 . A method according to  claim 4 , wherein the ratio of washing water to granulate is in a range of 5:1 to 40:1, preferably in a range of 8:1 to 20:1. 
     
     
         7 . A method according to  claim 4 , wherein the hydrated granulate is treated with a solution including thinned sodium hydroxide solution with an addition of sodium aluminate solution. 
     
     
         8 . A method according to  claim 7 , wherein the ratio of solution to granulate is in a range of 5:1 to 40:1, preferably in a range of 8:1 to 20:1. 
     
     
         9 . A method according to  claim 4 , wherein the duration of the treatment with the sodium aluminate solution is determined by the obtained degree of conversion of non zeolitic granulate components into desired zeolite material. 
     
     
         10 . A method according to  claim 4 , wherein an aging step with sodium aluminate solution or a solution with the same ingredients but another composition, however, at a lower temperature is performed over a time period of 0.5-24 hours, preferably 1-4 hours before performing the treatment with the sodium aluminate solution. 
     
     
         11 . An adsorption agent consisting of or comprising an adsorption agent granulate produced according to  claim 4 . 
     
     
         12 . A method for using the adsorption agent according to  claim 11  in processes for oxygen enrichment, hydrogen purification, natural gas processing, energy storage and similar adsorption processes.