Patent EA-003930-B1 (EA)
Title: Zeolite adsorbents, method for obtaining them and their use for removing carbonates from a gas stream
Inventor: GRAND-MOUGIN MARIE-THERESE
IPC: B01J20/30
Filed: 2000-10-03
Abstract: 1. Zeolite adsorbent, comprising 5-95% mixture, preferably 50-90% by weight, at least one X zeolite with Si/Al ratio equal 1.25 and 95-5%, preferably 50-10% by weight, at least one SLX zeolite with Si/Al ( 1, in which either at least 80% of summed sites of exchangeable cation of zeolite totality are occupied by sodium cations, either at least 70% of summed sites of exchangeable cation of zeolite totality are occupied by strontium cations, wherein the rest exchangeable sites may be occupied by cations, selected from IA, IIA, IIIA groups of periodic table, trivalent ions of the rare earth elements or lanthanides. 2. Zeolite adsorbent according to claim 1, characterized in that it is in the form of powder mixture of X and LSX zeolites. 3. Zeolite adsorbent according to claim 1, characterized in that further comprises a binder, comprising at least 25 mass parts, preferably at least 20 mass parts, and most preferably at least 5 mass parts per 100 mass parts of zeolite and binder mixture. 4. Zeolite adsorbent according to any one of claims 1 to 3, characterized in that moisture content of zeolite adsorbent is not more than 1% of the adsorbent total mass, preferably not more than 0.5% and, most preferably not more than 0.3%. 5. A method for obtaining adsorbent in the form of a powder as defined in claim 2 or 4, comprising mixing of X and LSX zeolites with one or plurality of possible cation exchange operations on X and/or LSX powders prior to mixing thereof or after their mixing. 6. A method for obtaining adsorbent in the form of a powder as defined in claim 3 or 4, comprising the following steps: A - agglomeration and forming the X and/or LSX powders with a binder; B - drying the product obtained in step A), at a low temperature and activation at temperature between 300 to 700 degree C, preferably from 400 to 600 degree C; C - optional zeolitization of the binder, if the binder is suitable for zeolitization; D - washing, drying and activation of the product obtained in stage C) at a temperature between 300 to 700 degree C, preferably from 400 to 600 degree C, or the product obtained after the cation exchange of the product obtained in step B); and, optionally, one or a plurality of cation exchange operations with subsequent washing with water; prior to step A), or on X and LSX powders before mixing thereof, or directly after their mixing in case of obtaining agglomerated adsorbent after step B) or D) depending on weather a binder is or not zeolitized; and/or after stage B), and/or after optional stage of zeolitization of zeolitazable binder on preliminary dried products obtained in step C) and prior to step D), wherein if neither cation exchange nor zeolitization are carried out, agglomerated adsorbent is obtained in step B). 7. Method of carbonation of gas flow, preferably air polluted with CO2, wherein being purified gas flow is reacted in the adsorption zone with at least one zeolite adsorbent such as defined in any one of claims 1 to 4, preferably agglomerated with a binder. 8. Method according to claim 7, wherein the zeolite adsorbent has total exchange rate on sodium higher than 90%, preferably higher than 98%. 9. Method according to claim 7, wherein the zeolite adsorbent has total exchange rate on strontium higher than 70%, and a majority of cation positions is occupied with sodium ions. 10. Method according to any one of claims 7 to 9, wherein operating using adsorption modulated by pressure (PSA), and, preferably adsorption modulated by pressure and temperature (PTSA). 11. Method according to any one of claims 7 to 10, wherein the adsorption pressure is between 1 to 10 bars, and desorption pressure is between 0.1 to 2 bars. 12. Method according to any one of claims 7 to 11, wherein comprises a treatment cycle comprising the steps of: a). introducing a polluted gas flow into an adsorption zone comprising an adsorption layer, wherein the adsorption layer provides separation of the polluted component or components for adsorption; b). desorption of adsorbed with CO2 by creating pressure gradient and gradual pressure lowering in said adsorption zone for recovering CO2 through an inlet into the adsorption zone; c). increasing pressure in said adsorption zone by introducing pure gas flow through an outlet from the adsorption zone. 13. The method according to claim 12, in which the zeolite adsorbent is agglomerated with zeolitized binder, in which adsorbent is regenerated in step b) at a temperature in the range of 100 to 120 degree C. 14. Method of air purification polluted with CO2 and H2O, wherein being purified gas flow is reacted in the adsorption zone with at least one drier, preferably based on aluminum oxide, and at least with one adsorbent, ( which is substantially X and LSX zeolite mixture, total exchange rate on sodium is equal or higher than 98%, ( agglomerated with a binder, and the content of residual inert binder in which is less or equal 25, preferably 20 and most preferably 5 mass parts per 100 mass parts of zeolite and binder mixture, and moisture content of which is preferably not more than 1%, not more than 0.5% of adsorbent total mass. 15. Method according to claim 14, wherein comprises a treatment cycle comprising the steps of: a). introducing a polluted gas flow into an adsorption zone comprising a drier layer and wherein an adsorption layer such as defined in claim 14; b). desorption of adsorbed with CO2 by creating pressure gradient and gradual pressure lowering in said adsorption zone for recovering CO2 through an inlet into the adsorption zone; c). increasing pressure in said adsorption zone by introducing pure gas flow through an outlet from the adsorption zone.