Zeolitic adsorbent for the separation of hydrocarbon isomers
The present invention concerns a zeolitic adsorbent agglomerate comprising at least one zeolite of faujasite type comprising barium and/or potassium, of porosity between 25% and 45%, and having a standard deviation σ of crystal size distribution in said agglomerate of less than 0.30 μm. The invention also concerns the use of the zeolitic adsorbent agglomerate for the separation of hydrocarbon mixtures, and the process for separating hydrocarbon mixtures using said zeolitic adsorbent agglomerate.
1 . An agglomerated zeolitic adsorbent comprising at least one faujasite FAU-X zeolite of Si/Al atomic ratio between 1.00 and 1.50, limits included, and comprising barium and optionally potassium,
wherein particle porosity of the absorbent is between 25% and 45%, limits included,
wherein the standard deviation σ of crystal size distribution in the agglomerate is between 0.05 and 0.30 μm, limits included, and
wherein the adsorbent comprises zeolite crystals of number mean diameter less than 1200 nm.
2 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the adsorbent comprises zeolite crystals of number mean diameter between 100 nm and 1200 nm.
3 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the adsorbent is in the form of beads of mean diameter between 100 μm and 1000 μm, limits included.
4 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the at least one FAU-X zeolite has a Si/Al atomic ratio of between 1.05 and 1.50, limits included.
5 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the adsorbent comprises barium with a content of barium oxide (BaO) higher than 10%, relative to the total weight of the adsorbent.
6 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the adsorbent comprises potassium with a content of potassium oxide K 2 O lower than 25%, relative to the total weight of the adsorbent.
7 . The agglomerated zeolitic adsorbent according to claim 1 , wherein no zeolitic structure other than the faujasite structure is detected by X-ray diffraction.
8 . The adsorbent according to claim 1 wherein the weight fraction of FAU zeolite is higher than or equal to 80% relative to the total weight of the adsorbent.
9 . A process comprising separating para-xylene from aromatic isomer fractions having 8 carbon atoms, using as a para-xylene adsorption agent an agglomerated zeolitic adsorbent according to claim 1 , in liquid phase or in gas phase.
10 . The process comprising separating para-xylene from isomer fractions of aromatic hydrocarbons having 8 carbon atoms according to claim 9 , in liquid phase further comprising adsorption of para-xylene in the presence of a desorbent.
11 . The process according to claim 9 of simulated moving bed type.
12 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the particle porosity of the absorbent is between 30% and 45%, limits included.
13 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the particle porosity of the absorbent is between 36% and 45%, limits included.
14 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the standard deviation σ of crystal size distribution in the agglomerate is between 0.1 μm and 0.28 μm, limits included.
15 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the standard deviation σ of crystal size distribution in the agglomerate is between 0.1 μm and 0.25 μm, limits included.
16 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the adsorbent comprises zeolite crystals of number mean diameter between 600 nm and 1200 nm.
17 . The agglomerated zeolitic adsorbent according to claim 1 , wherein the at least one FAU-X zeolite has a Si/Al atomic ratio of between 1.10 and 1.40, limits included.
18 . The agglomerated zeolitic adsorbent according to claim 1 wherein the weight fraction of FAU-X zeolite is higher than or equal to 80% relative to the total weight of the adsorbent.