Patent EA-001894-B1 (EA)
Title: Catalyst based on ferrierite/iron for catalytic reduction of nitrous oxide content in gases, method for obtaining same and application
Inventor: NEVEU BERNARD
IPC: B01J29/88
Filed: 1998-12-16
Abstract: 1. A composition zeolite ferrierite/iron comprising ferrierite containing 1-6% by weight of iron, preferably 2-4% by weight of iron. 2. Ferrierite/iron as claimed in claim 1, wherein comprises 0,5-1% of potassium as ions in the position of exchange. 3. Catalyst of N2O conversion formed by agglomerates from 0-90% of ferrierite as claimed in claims 1 or 2, and 20-10% of argillaceous, silicate or alumina bond of agglomeration. 4. A method for reducing of nitrous oxide content in gases, N2O content in which comprises from 500 ppm to 50%, N2O from 0,05 to 5 % and NO from 50 to 2000 ppm, providing passing said gases through a catalyst bed raised to a temperature 350/600 degree C, wherein the catalyst is an agglomerate such as claimed in claim 3. 5. The method as claimed in claim 4, wherein said gases are gases generated by installations producing nitric acid comprising  N2O: from 500 to 1500 ppmv; NOx: from 50 to 2000 ppmv; N2O: from 0,5 to 5%; oxygen: about 2%, wherein remaining (up to 100%) is essentially nitrogen  6. The method as claimed in claim 4, wherein said gases are gases generated by installations producing organic substances by oxydation with nitric acid which, to eventual dilution with air, comprise: N2O: 20-50% ppmv; NOx: from 50 to 5000 ppmv; N2O: 0,5-5%; oxygen: 1-4% CO2: about 5%; wherein remaining (up to 100%) is essentially nitrogen  7. A method for preparing a catalyst of the N2O conversion as claimed in claim 3, wherein  agglomerating ferrierite powder with a bond comprising argillaceous, silicate or alumina bonds; forming a corresponding paste in extrudes, filaments comprising 80-90% of ferrierite and 20-10% of bond per w/w % of dry substance; firing at a temperature of about 400 degree C; ion-exchanging at least once with aqueous solution of an iron salt, wherein the ferrierite subjected to the ion exchange comprises 1-6%, and preferably 2-4% by weight of iron. the agglomerate, subjected to the ion exchange, is dried. 8. The method for preparing a catalyst of the N2O conversion as claimed in claim 3, wherein  subjecting a ferrierite power to the ion exchange at least once with the aqueous solution of the iron salt, wherein the ferrierite subjected to said ion exchange comprises 1-6%, and preferably 2-4% by weight of iron; agglomerating the ferierite powder subjected to the ion exchange with a bond selected from the group comprising argillaceous, silicate or alumina bonds; forming a corresponding paste in extrudes, filaments comprising 80-90% of ferrierite and 20-10% of bond per w/w % of dry substance; the agglomerate, subjected to the ion exchange, is dried and, if necessary fired at a temperature of about 400 degree C. 9. The method as claimed in claims 7 and 8, wherein the agglomerating bond is clay selected individually as a mixture from the group comprising kaolinite, attapulgite, bentonite and halloysite. 10. The method as claimed in claims 7 and 8, wherein the agglomerating bond is alumine peptized oxide. 11. The method as claimed in claims 7 to 10, wherein the iron salt is ferrous iron. 12. The method as claimed in claims 7 to 10, wherein the iron salt is ferric iron. 13. The method as claimed in claims 8 to 112, wherein prior to the agglomerating the ferrierite powder is subjected to one or several ion exchanges with aqueous solution of ammonium salt. 14. The method as claimed in any of claims 7 or 9 to 12, wherein prior to the ion exchange with the iron salt solution, the agglomerates are subjected to one or several ion exchanges with aqueous solution of ammonium salt.