MXPA97003042A - Procedure for the preparation of a catalyst for selective oxidation of acid gases and the product results - Google Patents
Procedure for the preparation of a catalyst for selective oxidation of acid gases and the product resultsInfo
- Publication number
- MXPA97003042A MXPA97003042A MXPA/A/1997/003042A MX9703042A MXPA97003042A MX PA97003042 A MXPA97003042 A MX PA97003042A MX 9703042 A MX9703042 A MX 9703042A MX PA97003042 A MXPA97003042 A MX PA97003042A
- Authority
- MX
- Mexico
- Prior art keywords
- catalyst
- support
- present
- elemental sulfur
- constituted
- Prior art date
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000002253 acid Substances 0.000 title claims abstract description 18
- 230000003647 oxidation Effects 0.000 title claims abstract description 17
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 17
- 239000007789 gas Substances 0.000 title claims description 15
- 238000002360 preparation method Methods 0.000 title claims description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 37
- NINIDFKCEFEMDL-UHFFFAOYSA-N sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 18
- 229910000460 iron oxide Inorganic materials 0.000 claims abstract description 15
- 235000013980 iron oxide Nutrition 0.000 claims abstract description 15
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 239000012072 active phase Substances 0.000 claims abstract description 10
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 6
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 6
- 239000011148 porous material Substances 0.000 claims abstract description 6
- OZAIFHULBGXAKX-UHFFFAOYSA-N precursor Substances N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims abstract description 5
- 102000014961 Protein Precursors Human genes 0.000 claims abstract 2
- 108010078762 Protein Precursors Proteins 0.000 claims abstract 2
- 239000011149 active material Substances 0.000 claims abstract 2
- 239000012071 phase Substances 0.000 claims abstract 2
- 230000001131 transforming Effects 0.000 claims abstract 2
- 239000011593 sulfur Substances 0.000 claims description 10
- 229910052717 sulfur Inorganic materials 0.000 claims description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical class [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- 238000011084 recovery Methods 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 6
- 239000007864 aqueous solution Substances 0.000 claims description 5
- 230000001590 oxidative Effects 0.000 claims description 5
- 238000001354 calcination Methods 0.000 claims description 4
- 238000005470 impregnation Methods 0.000 claims description 4
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 4
- 239000011780 sodium chloride Substances 0.000 claims description 4
- 230000004913 activation Effects 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 159000000014 iron salts Chemical class 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- VLTRZXGMWDSKGL-UHFFFAOYSA-M Perchlorate Chemical class [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 claims description 2
- 150000001860 citric acid derivatives Chemical class 0.000 claims description 2
- 150000002823 nitrates Chemical class 0.000 claims description 2
- 150000003891 oxalate salts Chemical class 0.000 claims description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N Iron(III) oxide Chemical compound O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims 2
- 230000000737 periodic Effects 0.000 claims 1
- 230000000704 physical effect Effects 0.000 claims 1
- 229910052615 phyllosilicate Inorganic materials 0.000 description 9
- 239000000203 mixture Substances 0.000 description 5
- 230000003197 catalytic Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N AI2O3 Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000024881 catalytic activity Effects 0.000 description 2
- 150000002505 iron Chemical class 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- NPFOYSMITVOQOS-UHFFFAOYSA-K 2-hydroxypropane-1,2,3-tricarboxylate;iron(3+) Chemical compound [Fe+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NPFOYSMITVOQOS-UHFFFAOYSA-K 0.000 description 1
- HUTBITLDXCEAPZ-UHFFFAOYSA-N 2-hydroxypropane-1,2,3-tricarboxylic acid;iron Chemical compound [Fe].OC(=O)CC(O)(C(O)=O)CC(O)=O HUTBITLDXCEAPZ-UHFFFAOYSA-N 0.000 description 1
- KSECJOPEZIAKMU-UHFFFAOYSA-N [S--].[S--].[S--].[S--].[S--].[V+5].[V+5] Chemical compound [S--].[S--].[S--].[S--].[S--].[V+5].[V+5] KSECJOPEZIAKMU-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 230000001737 promoting Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory Effects 0.000 description 1
- GRUMUEUJTSXQOI-UHFFFAOYSA-N vanadium dioxide Chemical compound O=[V]=O GRUMUEUJTSXQOI-UHFFFAOYSA-N 0.000 description 1
- 229910001935 vanadium oxide Inorganic materials 0.000 description 1
Abstract
The object of the present invention is the process for obtaining a catalyst that will be used in the transformation of gas-acid to elemental sulfur, constituted by iron oxides supported on enriched silica, which can be used as a catalyst for the selective oxidation of gas-acid to elemental sulfur and Water. The present invention relates to the process for obtaining a catalyst consisting of iron oxides, which are obtained starting from different precursors and, in addition, whose active phase is highly dispersed on the support, the specific area of the relatively large catalyst being 500 at 600 m2 / g and a pore radius between 5-50 A. The catalyst generally contains at least 0.1% by weight of iron oxides, calculated with respect to the total mass of the catalyst, this phase of the material being catalytically active for selective oxidation from H2S to elemental sulfur. The catalytically active material is preferably constituted by metal oxides. The catalyst resulting from the process also forms part of the present invention. Additionally, the present invention reports the obtaining of a catalyst for selective oxidation, where an inert support is used, different to the supports for commercial use hitherto known. According to the present invention, it is reported the obtaining of a catalyst with which have reached levels of conversion of gas acid to elemental sulfur greater than 95% reported by current commercial catalysts
Description
PROCEDURE FOR THE PREPARATION OF A CATALYST FOR SELECTIVE GAS OXIDATION
ACIDS AND THE RESULTING PRODUCT
D E S C R I P C I O N
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a process for preparing an appropriate catalyst for the recovery of sulfur by selective oxidation of acid gases in a step after the Claus process. The catalyst preparation comprises the following steps: (1) activation of the support, (2) impregnation thereof with a solution containing a salt of the element that will provide the active phase of the catalyst, (3) drying and (4) calcination. By means of this process, a catalyst constituted by iron oxides supported on silica enriched with laminar phyllosilicates was obtained, the ideal oxide compositions being 0.1% to 10% by weight with respect to the total weight. The invention also relates to the high level of the resulting catalytic activity for the conversion of H2S to sulfur and water from the acid gas emissions of the Claus plants.
BACKGROUND OF THE INVENTION
The efficiency of recovery of sulfur in a typical CLAUS plant of 3 converters can reach up to 91% under optimal conditions, however the current environmental regulations require regulating the emission levels of S02 at 250 ppm / vol or its equivalent, ie a recovery overall from 99.7% to 99.9%, for which an additional process of deep sulfur recovery is necessary to achieve more than 97% recovery through the Claus process, thus reducing the emission of S02 within the permitted limits. Said additional process is applied at a later stage to the Claus process, consisting of a selective oxidation to transform the remaining acid gas to elemental sulfur and water.
US Pat. No. 4,818,740 protects the preparation of a catalyst for selective oxidation formed by Fe2? 3-Cr2? 3 / a -AI2O3 with a concentration of 4.5%) and 0.5% by weight, respectively, whereby a conversion is achieved from acid gas to sulfur greater than 90%.
US Patent No. 4,31 1, 683 protects the process of converting H 2 S to sulfur by using a Vanadium oxide and Vanadium sulfide catalyst, on a non-alkaline porous oxide.
Unlike what is claimed in US Patents No. 4,311, 683 and No.
4,818,740 the active phase used in our catalyst contains only one oxide of the group VIIIA and the support used is also different to the previously reported being in our particular case Si02 granular and a fraction of laminar phyllosilicates of high surface area.
Due to the foregoing and due to the novel characteristics and simplicity in the process for the preparation of this catalyst, the present invention is considered as an important advance in the area of the catalysts hitherto used for the selective oxidation of H2S for the recovery of sulfur. .
According to the present invention, a catalyst constituted by iron oxides supported on silica enriched with phyllosilicates has been developed, with different concentrations by weight, which has the property of not promoting the Claus equilibrium reaction and also avoids the oxidation of sulfur to S02, without modifying other gaseous compounds such as COS, CS2, H2 and C02; In addition, this catalyst is insensitive to high concentrations of water vapor and an excess of oxygen, which is why it is classified as extremely selective for the oxidation of H2S at moderate temperatures.
The present invention provides an improved process for preparing a catalyst composition for the selective oxidation of H 2 S, said process includes a preparation of the active catalyst based on iron oxides supported on silica enriched with laminar phyllosilicates.
The present invention also provides an improved catalytic composition of iron oxides supported on enriched silica which makes it possible to obtain a conversion of acid gas with high selectivity to elemental sulfur and water, equal to or greater than 95% with respect to the acid gas introduced into the charge.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an improved process for the
Preparation of a catalyst based on iron oxide supported on granular silica
enriched, where the iron oxide is in different proportion by weight, the
which can range from 0.1 to 10%.
The process for the preparation of the catalyst comprises the following steps:
(1) - Activation of the support at a temperature between 100-400 ° C, preferably 120 ° C,
for a period of 1 to 4 hours.
(2) -Impregnation at room temperature of the activated support by the addition of
an aqueous solution of a precursor agent based on organic salts of iron,
according to percentages in weight that can go from 0.1% to 10% of iron oxides,
preferably between 2.5 and 5%.
(3) -Drying at reduced pressure between 100 and 200 mmHg and at a temperature between 50 and
250 ° C, for a period of 24 to 168 hours.
(4) - Calcination in oxidizing atmosphere at a temperature between 300 and 675 ° C, preferably 500 ° C, for 1 to 10 hours. As raw materials for achieving the process of this invention, those mentioned below may be used: The active phase support is preferably an oxide, such as granular silica enriched with layered phyllosilicates or alpha-type alumina and, as precursor agents of the active phase, any of the accessible iron salts can be used, such as nitrates, sulfates, citrates, perchlorates, oxalates, etc. or another type of organic iron salts.
As novel aspects of the present invention, we can mention, on the one hand, the nature of the support, the combination with the composition of the active phase, both subjected to the specific treatment that constitutes, properly, the procedure that is described and claimed. The catalyst resulting from the claimed process is constituted by iron oxides ranging from 0.1 to 10% by weight, preferably 2.5 to 5%, based on the granular silica enriched with laminar phyllosilicates.
Some practical examples related to the described procedure are described below, without limiting the scope of the invention.
EXAMPLE 1. Using as support of the active phase a metal oxide such as silica enriched with laminar phyllosilicates, in spheres of 3/16"diameter, with a high surface area of 726 m / g, pore volume of 0.39 cm / g and a pore diameter of 21 A, a pre-treatment of drying is carried out at a temperature between 100 and
250 ° C, for 1 to 3 hours, then adding an aqueous solution of an iron salt, preferably nitrate, maintaining heating for 1 to 3 hours and then evaporating the solvent to dryness and the resulting material is dried at temperatures between 100 and 250 ° C, at reduced pressure, for a period of 24 to 120 hours and, finally, it is calcined in an oxidizing atmosphere at temperatures between 300 and 750 ° C, preferably between 450 and 550 ° C.
EXAMPLE 2. "The catalyst prepared in Example 1, gave an average conversion of H2S to sulfur of 40% at 240 ° C, with a GHSV of 1500 h" 1.
EXAMPLE 3. The procedure of example 1 is followed, with the variant that a calcination treatment of 300 to 650 ° C is applied to the support, for a period of 3 to 6 hours, prior to impregnation.
EXAMPLE 4. Following the same procedure as in Example 1, granular silica enriched with layered phyllosilicates was used, with a surface area of 733m / g, a pore volume of 0.3866 cm3 / g and a pore size of 21 A.
EXAMPLE 5. Under the same conditions of Example 2, the variant of the support based on granular silica enriched with laminar phyllosilicates was used.
EXAMPLE 6 - Using as enriched granular silica support, mentioned in examples 3 and 4, a drying treatment between 100 and 250 ° C is applied, for a period of
1-4 hours and then calcined between 300 and 650 ° C, for 3-6 hours, impregnating at room temperature with an aqueous solution containing an iron salt, preferably iron (III) citrate, in a concentration that can go from 0.1 to 10% by weight of iron in relation to the support, keeping under heating for 1 to 3 hours and, subsequently, eliminating the solvent in its entirety and drying the resulting material at temperatures between 100 and 250 ° C under reduced pressure, for a period of 24-120 hours. Finally, it is calcined in an oxidizing atmosphere between 300-750 ° C, preferably between 450-550 ° C.
EXAMPLE 7. The catalyst obtained in Example 5 was catalytically evaluated in the reaction of oxidation of acid gas to elemental sulfur, operating at 240 ° C with a GHSV of 1500 h "1, giving an average conversion of 75% during 20 hours. hours.
EXAMPLE 8.- Using the granular silica mentioned in Examples 3 and 4 as support, it is activated at 100-250 ° C, for 1 to 3 hours and then impregnated with an iron citrate solution, containing 0.1% 10% by weight of iron. The heating is maintained for 1 to 3 hours and, subsequently, all the solvent is evaporated and dried at temperatures between 100 and 250 ° C, under reduced pressure, for a period of 24 to 120 hours and, finally, it is calcined in an atmosphere oxidant at 300-750 ° C, preferably between 450-550 ° C.
EXAMPLE 9. The catalyst obtained in example 8, presents catalytic activity in the conversion of acid gas to elemental sulfur, having a conversion higher than 95% at a temperature of 240 ° C and with a GHSV of 1500 h "1.
Claims (6)
1. - Process for the preparation of a catalyst for the selective oxidation of acid gases such as H2S to elemental sulfur, characterized in that it comprises the following steps: (a) - Activation of the support at a temperature between 100-400 ° C, preferably 120 ° C , for a period of 1 to 4 hours. (b) -Impregnation at room temperature of the activated support by the addition of an aqueous solution of a precursor agent based on organic iron salts, according to percentages by weight ranging from 0.1% to 10% of iron oxides, preferably between 2.5 and 5%. (c) -Drying under reduced pressure between 100 and 200 mmHg and at a temperature between 50 and 250 ° C, for a period of 24 to 168 hours. (d) - Calcination in oxidizing atmosphere at a temperature between 300 and 675 ° C, preferably 500 ° C, for 1 to 10 hours.
2. - Process for the preparation of a catalyst according to clause 1, characterized in that the salt used to form the aqueous solution of the precursor of the active phase, is selected from the group of nitrates, sulfates, citrates, perchlorates, oxalates, and other organic salts of iron.
3. - Process for the preparation of a catalyst, obtained in accordance with clause 1, characterized in that the support of the active phase is constituted by a material selected from the group of metal oxides, constituted mainly by silica of high specific rank.
4. - A catalyst obtained according to the method of clauses 1 - 3 characterized in that it is formed by iron (III) oxide containing 0.1 to 10% by weight of the metal oxide in relation to the support preferably between 2.5 and 5%, the support is constituted by silica enriched with laminar filisilicates.
5. - A catalyst obtained in accordance with clauses 1-4 constituted by a silica support mainly, and a metal oxide of group VIIIA of the Periodic Table characterized in that it consists mainly of silica with specific physical properties.
6. - A catalyst obtained in accordance with clauses 1-5, characterized in that it has an ability to convert acid gas to elemental sulfur, greater than 95% with a sulfur recovery of at least 90%. SUMMARY The object of the present invention is the process for obtaining a catalyst that will be used in the transformation of acid gas to elemental sulfur, constituted by iron oxides supported on enriched silica, which can be used as a catalyst for the selective oxidation of gas acid to elemental sulfur and water. The present invention relates to the process for obtaining a catalyst constituted by iron oxides, which are obtained starting from different precursors and, in addition, whose active phase is highly dispersed on the support, the specific area of the catalyst being relatively large from 500 to 600 m / g and a pore radius between 5-50 A. The catalyst generally contains at least
0. 1% by weight of iron oxides, calculated with respect to the total mass of the catalyst, this phase of the material being catalytically active for the selective oxidation of H2S to elemental sulfur. The catalytically active material is preferably constituted by metal oxides. The catalyst resulting from the process also forms part of the present invention. Additionally, the present invention reports the obtaining of a catalyst for selective oxidation, where an inert support is used, different to the supports for commercial use hitherto known. According to the present invention, the production of a catalyst with which levels of conversion of acid gas to elemental sulfur greater than 95% »reported by current commercial catalysts have been achieved.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MXPA/A/1997/003042A MXPA97003042A (en) | 1997-04-25 | Procedure for the preparation of a catalyst for selective oxidation of acid gases and the product results | |
| US09/065,448 US6083473A (en) | 1997-04-25 | 1998-04-24 | Selective oxidation catalyst, preparation and use thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MXPA/A/1997/003042A MXPA97003042A (en) | 1997-04-25 | Procedure for the preparation of a catalyst for selective oxidation of acid gases and the product results |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| MX9703042A MX9703042A (en) | 1998-10-31 |
| MXPA97003042A true MXPA97003042A (en) | 1999-01-11 |
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