JPH0220561B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a catalyst for oxidizing organic sulfur compounds and its use. More specifically,
The present invention relates to a catalyst for oxidizing carbon disulfide and/or carbonyl sulfide and/or mercaptan simultaneously with hydrogen sulfide or in the absence of hydrogen sulfide and its use. It is known to treat effluents containing organic sulfur compounds by catalytic methods. In such a method, the organic sulfur compound is hydrolyzed to convert it to hydrogen sulfide. The hydrogen sulfide produced is an extremely harmful pollutant gas and must be removed. This removal generally has to be carried out according to a Claus reaction or by thermal incineration at high temperatures. Certain industrial effluents, particularly those from Claus units, contain sulfur and/or oxidizable polluting sulfur compounds that are treated to be converted by oxidation to sulfur dioxide. Must be. The specific sulfur compounds present in such effluents are primarily hydrogen sulfide and organic sulfur compounds such as carbon disulfide and/or carbonyl sulfide and/or mercaptans. It is thus known to treat effluents containing hydrogen sulfide by burning them at high temperatures, but this method is energy-intensive and, from a technical point of view, It is not currently used due to the large amount of demand. Contact methods have also been proposed for treating gases containing hydrogen sulfide; however, such methods lack sufficient catalytic activity and cannot completely oxidize hydrogen sulfide at sufficiently low temperatures. It has drawbacks such as insufficient catalyst life. Furthermore, from French Patent Application No. 2144148, the general formula M _1x Cr _z Fe _2-z Ou (where M=Zn, Cu,
It is known that sulfur compounds contained in sulfur dioxide gas can be oxidized by catalytic rearrangement at 400 to 600°C in the presence of a catalyst containing an active phase consisting of a spinel-type hybrid oxide of Co, Ni, Mg, Mn or Cd). It is being
Apart from its unsatisfactory performance, such catalysts require a minimum
There are considerable inconveniences, such as the need for calcination at a temperature of 650°C for 4 hours. The inventors have developed a catalytic process that converts organosulfur compounds, optionally with sulfur and hydrogen sulfide, into fairly innocuous compounds in a single step. This method does not contain a spinel-type hybrid oxide in the active phase and
It involves the catalytic oxidation of organic sulfur compounds to sulfur dioxide in excellent yields in the presence of catalysts prepared at temperatures below 550°C. Thus, the catalyst has very high catalytic activity and also exhibits an exceptionally long lifetime. The present invention provides a catalyst for oxidizing an organic sulfur compound to sulfur dioxide together with sulfur and hydrogen sulfide as appropriate.
At least one containing magnesia, silica-zirconia or silica-titanium oxide as one component and selected from the group consisting of copper, silver, molybdenum, tungsten, iron, bismuth, lanthanide, chromium, rhodium, iridium, palladium, platinum and tin. The present invention relates to a catalyst characterized by containing one type of element as another component. The present invention also provides a method for vapor-phase oxidation of an organic sulfur compound to sulfur dioxide together with sulfur and hydrogen sulfide as appropriate, the method comprising silica, zirconium oxide, silica-magnesia, silica-zirconia or silica-titanium oxide as one component, and copper, silver, molybdenum,
On a catalyst containing as another component at least one element selected from the group consisting of tungsten, iron, bismuth, lanthanide, chromium, rhodium, iridium, palladium, platinum and tin, at least one organic sulfur compound and optionally It relates to a method characterized by passing a gas containing sulfur and hydrogen sulfide. The catalyst according to the invention can be manufactured by conventional methods. It is in particular a support based on silica, zirconium oxide, silica-magnesia, silica-zirconia or silica-titanium oxide that is impregnated with the catalytically active element or its precursor, or a support based on silica, zirconium oxide or silica-zirconia or It can be prepared by malaxating a powder of a silica-titanium oxide mixture with a precursor of the catalytically active component. The catalysts can also be prepared by coating refractory oxides with precursors of silica, zirconium oxide or silica-zirconia or silica-titanium oxide mixtures, and also with catalytically active elements or precursors thereof. . When the term precursor is used herein, it shall mean any compound capable of donating said element or the corresponding oxide upon heating. Whatever the method of production, the catalyst of the invention is, in the final step, calcined free of spinel-type hybrid oxides at temperatures below 550°C. Thus, calcination of such catalysts generally takes about
It is carried out at a temperature in the range 300°C to 550°C, preferably 350°C to 450°C. The zirconium oxide supported catalyst according to the invention preferably has a specific surface area of about 5 to 250 ^{m 2} /g, more preferably 20 to 150 m ² /g. Also, the silica, silica-magnesia, silica-zirconia or silica-titanium oxide supported catalyst according to the invention preferably has a
m ² /g, more preferably 80 to 500 m ² /g. The atomic ratio of catalytically active elements/silicon, zirconium, magnesium or silicon-magnesium or silicon-titanium mixtures present in the catalyst is approximately
It is in the range of 0.00005 to 0.1. The process for vapor phase oxidation of organosulfur compounds to sulfur dioxide, optionally with sulfur and hydrogen sulfide, in the presence of the catalysts of the invention can be carried out by contacting the effluent containing the compounds with a molecular oxygen-containing gas. This gas is generally air, but may optionally be oxygen-enriched air or pure oxygen. The gas thus contains an amount at least equal to, and preferably equal to, the stoichiometric or stoichiometric amount necessary to oxidize all the organic sulfur compounds and any sulfur and hydrogen sulfide to sulfur dioxide. Contains more oxygen. Advantageously, the amount of oxygen present in the gas is approximately 15-100% greater than the theoretical amount. The process of the invention is carried out at temperatures above about 150<0>C, preferably in the range of about 200-550<0>C. The composition of the gases that can be treated according to the method of the invention can vary over a wide range. Generally, industrial effluents that can be treated according to the present invention preferably contain about 0.1 to 5% by volume of sulfur compounds. The amount of catalyst used is preferably such that VVH (volume of gas treated per volume of catalyst per hour) is 1000
~30000, preferably in the range 1500-10000. The following examples are intended to illustrate the invention and are not intended to limit its scope. Example 1 A silica carrier manufactured by Rhone Poulenc was used. This support has a specific surface area of 480 m ² g ^-1 . The carrier is impregnated with a ferrous sulfate solution that has been slightly acidified with sulfuric acid. Dry this at 150℃ for 2 hours,
Calcinate at ℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 410 m ² g ^-1 Atomic ratio: Fe/Si = 0.05 Example 2 The support of Example 1 was impregnated with an ammoniacal cuprous chloride solution and heated at 110°C. Dry for 8 hours and calcinate at 450℃ for 2 hours. The catalyst has the following specific values: Specific surface area: SBE = 380 m ² g ^-1 Atomic ratio: Cu/Si = 0.04 Example 2 Silica content 70% by weight and titanium oxide 30% by weight
Uses a silica-titanium oxide support. This carrier is
It has a specific surface area of 350 m ² /g. This carrier is impregnated with an ammoniacal cuprous chloride solution, dried at 150°C, further impregnated with a ferric nitrate solution, and calcined at 400°C for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 325 m ² g ^-1 Atomic ratio: Cu + Fe / Si + Ti = 0.06, Cu / Fe = 2 Example 4 The catalyst of Example 1 was impregnated with iridium chloride solution and heated at 110°C. It is dried for 24 hours, then calcined at 400℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 379 m ² g ^-1 Atomic ratio: Cu + Ir / Si = 0.06015, Cu / Ir = 400 Example 5 The silica support used in Example 11 was impregnated with ammonium paramolybdate solution. and dried at 110℃ overnight.
Then, it is calcined at 450℃ for 2 hours. The catalyst has the following properties: Specific surface area: SBE = 370 m ² g ^-1 Atomic ratio: Mo/Si = 0.06 Example 6 A silica-magnesia support with a silica content of 60% by weight and a magnesia content of 40% by weight was used. This support has a specific surface area of 240 m ² /g. The carrier is impregnated with ammonium paramolybdate solution, dried at 150°C for 4 hours, and calcined at 400°C for 2 hours. The produced catalyst has the following characteristic values: Specific surface area: SBE = 215 m ² g ^-1 Atomic ratio: Mo / Si + Mg = 0.05 Example 7 The silica support used in Example 1 was impregnated with a nitric acid solution of bismuth nitrate and heated at 110°C. It is dried for 24 hours, then calcined at 450℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 373 m ² g ^-1 Atomic ratio: Bi / Si = 0.04 Example 8 The catalyst of Example 7 was impregnated with a rhodium chloride solution,
Dry at 110℃ for 24 hours, then calcinate at 400℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 371 m ² g ^-1 Atomic ratio: Bi + Rh / Si = 0.0401, Bi / Rh = 400 Example 9 A zirconium oxide support with a specific surface area of 82 m ² g ^-1 and nitric acid Impregnated with iron solution and dried at 150℃ for 8 hours,
Then, it is calcined at 450℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 76 m ² g ^-1 Atomic ratio: Fe / Zr = 0.04 Atomic ratio: Fe + La / Zr = 0.06, Fe / La = 1 Atomic ratio: Fe + Sn / Zr = 0.06, Fe/Sn=2

【table】

[Table] Example 13 This example, like Example 12, also shows an application example of the catalyst of the present invention obtained in Examples 1 to 11. A gas having the following volumetric composition: H ₂ S: 800 ppm COS: 100 ppm CS ₂ : 500 ppm SO ₂ : 400 ppm O ₂ : 2% H ₂ O: 30% N ₂ : 67.82% is fed into the reactor containing the catalyst. VVH is 1800 and gas inlet temperature is 380℃. The results achieved with each catalyst are listed in the table below:

[Table] Example 14 In this example, a silica-zirconia support containing 70% by weight of silica and 30% by weight of zirconia is used. Its specific surface area is 260 m ² /g. This carrier was impregnated with chromium acetate solution and heated to 400°C.
Bake for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 220 m ² g ^-1 Atomic ratio: Cr/Si + Zr = 0.05 Example 15 The silica support used in Example 1 was impregnated with a metatungstic acid solution and dried at 110°C overnight. and then 450
Calcinate at ℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 270 m ² g ^-1 Atomic ratio: W/Si = 0.07 Example 16 The silica support used in Example 1 was impregnated with a silver nitrate solution and dried at 110°C for 24 hours. , then calcined at 450℃ for 2 hours. The present catalyst has the following characteristic values: Specific surface area: SBE = 373 m ² g ^-1 Atomic ratio: Ag/Si = 0.04 Example 17 The catalyst obtained in Example 15 was impregnated with a chloroplatinic acid solution,
Dry at 110℃ for 24 hours, then calcinate at 400℃ for 2 hours. This catalyst has the following characteristic values: Specific surface area: SBE = 385 m ² g ^-1 Atomic ratio: W + Pt / Si = 0.11, W / Pt = 3 Example 18 The catalyst obtained in Example 14 was impregnated with a palladium chloride solution, ℃ for 24 hours, then calcined at 450℃ for 2 hours. The catalyst has the following characteristic values: Specific surface area: SBE = 185 m ² g ^-1 Atomic ratio: Cr + Pd / Si + Zr = 0.06, Cr / Pd = 150 Example 19 In this example, the same test conditions as described in Example 13 were followed. Each catalyst obtained in steps 14 to 18 is used. The results are shown in the table below:

【table】

【table】

Claims (1)

[Scope of Claims] 1. A catalyst for oxidizing an organic sulfur compound containing or not containing hydrogen sulfide, containing silica, zirconium oxide, silica-magnesia, silica-zirconia, or silica-titanium oxide as one component, and containing copper as one component. , silver, molybdenum, tungsten,
iron, bismuth, lanthanides, chromium, rhodium,
A catalyst characterized by containing as another component at least one element selected from the group consisting of iridium, palladium, platinum and tin. 2 Contains zirconium oxide and has a specific surface area of approximately 5~
250 m ² /g of the catalyst according to claim 1. 3 Contains silica and has a specific surface area of approximately 50 to 600 m ² /g
The catalyst according to claim 1, characterized in that: 4 The atomic ratio of the catalytically active element/silicon, zirconium, magnesium or silicon-magnesium or silicon-titanium mixture present in the catalyst is approximately
The catalyst according to claim 1, characterized in that it has a molecular weight of 0.00005 to 0.1.