A claus tail gas combustion catalyst, a preparation method and application thereof

Abstract

The application provides a Claus tail gas combustion catalyst and a preparation method and application thereof. The catalyst is prepared by loading active components scandium oxide and chromium oxide on a high-purity and ultra-low-iron-impurity-content silicon dioxide carrier; the high-purity and ultra-low-iron-impurity-content silicon dioxide has a silicon dioxide content of >99.9% and an iron oxide content of <0.01%; and the loaded active components do not contain iron oxide. The catalyst is suitable for catalytic combustion of tail gas of a sulfur recovery device, can oxidize hydrogen sulfide, elemental sulfur and organic sulfur in the gas into sulfur dioxide at a low temperature of 300-350 DEG C, avoids the problem that ordinary combustion catalysts simultaneously deeply oxidize part of the sulfur dioxide into sulfur trioxide, thereby causing a small amount of sulfur trioxide in the gas after combustion, and effectively solves the problems of serious corrosion of the device and large amount of salt-containing wastewater caused by sulfur trioxide in the next step of tail gas treatment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of natural gas, refinery gas and coal chemical gas processing, and particularly relates to a Claus tail gas incineration catalyst capable of effectively inhibiting the generation of sulfur trioxide as well as a preparation method and application thereof. BACKGROUND

[0002] The Claus sulfur recovery process technology is generally used in natural gas purification plants, oil refineries and coal chemical plants to recover sulfur from sour gas containing hydrogen sulfide. This technology can generally convert 90-97% of the hydrogen sulfide in the sour gas into sulfur. The tail gas after sulfur recovery generally contains 0.5-2% of hydrogen sulfide, 0.01-0.5% of organic sulfur, 0.02-0.1% of elemental sulfur and 0.2-1% of sulfur dioxide by volume. For those without subsequent tail gas treatment process, the tail gas is generally incinerated at 500-600℃ by adding an appropriate amount of air to oxidize the non-sulfur dioxide sulfides into sulfur dioxide before being discharged, which is the conventional incineration. For those using the oxidation absorption type tail gas treatment process (such as the Consof process), the tail gas is also incinerated by adding an appropriate amount of air to oxidize the non-sulfur dioxide sulfides into sulfur dioxide before being treated in the next step. Since there are strict requirements for the residual hydrogen sulfide and organic sulfur concentrations in the incinerated tail gas, the incineration temperature is 750-850℃, which is high-temperature incineration.

[0003] Hot incineration usually consumes a large amount of fuel gas. In order to achieve energy saving, the Claus tail gas catalytic incineration technology has been developed. By loading catalysts in the incinerator, the effect of hot incineration at 500-600℃ can be achieved at 300-350℃. The catalytic incineration catalyst usually uses silica gel or silica-alumina as the carrier and chromium oxide and iron oxide as the active components. For conventional incineration, it is generally required that the hydrogen sulfide concentration in the incinerated gas is <10 ppm by volume, the organic sulfur concentration is <20 ppm by volume, and there is no requirement for the concentration of sulfur trioxide. Both catalytic incineration and hot incineration can achieve this index, therefore, the catalytic incineration technology has been widely used in conventional incineration devices of Claus tail gas. However, for high-temperature incineration, if catalytic incineration is used to replace hot incineration, under the premise that the hydrogen sulfide concentration in the incinerated gas is <10 ppm by volume and the organic sulfur concentration is <20 ppm by volume, there is 100-200 ppm by volume of sulfur trioxide in the incinerated gas, which cannot meet the requirement of <10 ppm by volume of sulfur trioxide proposed by the subsequent tail gas treatment process, and will lead to serious corrosion of the tail gas treatment device and a large amount of salt-containing wastewater. Therefore, the catalytic incineration technology has not been applied in high-temperature incineration devices. The core problem of promoting the industrial application of catalytic incineration technology in the oxidation absorption type tail gas treatment process device is to develop a catalytic incineration catalyst that can effectively inhibit the generation of sulfur trioxide. SUMMARY

[0004] The present application aims to provide a Claus tail gas incineration catalyst capable of effectively inhibiting the generation of sulfur trioxide (a device with a detection lower limit of 1 ppm cannot detect the presence of sulfur trioxide), and a preparation method and application thereof. The catalyst is suitable for catalytic incineration of tail gas of a sulfur recovery device, and can oxidize hydrogen sulfide, elemental sulfur and organic sulfur in the gas to sulfur dioxide at a low temperature of 300-350 DEG C, while avoiding the problem that ordinary incineration catalysts simultaneously oxidize part of the sulfur dioxide to sulfur trioxide, resulting in a small amount of sulfur trioxide in the gas after incineration. The problem of severe corrosion of the device and large amount of salt-containing wastewater caused by sulfur trioxide in the next step of tail gas treatment can be effectively solved.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following three technical solutions.

[0006] In the first aspect, the present application provides a Claus tail gas incineration catalyst, wherein the catalyst is loaded with active components scandium oxide and chromium oxide on a high-purity and ultra-low-iron-impurity silica carrier.

[0007] Among the high-purity and ultra-low-iron-impurity silica, the silica content is > 99.9% and the iron oxide content is < 0.01% based on the total mass of the high-purity and ultra-low-iron-impurity silica being 100%.

[0008] Among the high-purity and ultra-low-iron-impurity silica, the silica content is > 99.9% and the iron oxide content is < 0.01% based on the total mass of the high-purity and ultra-low-iron-impurity silica being 100%.

[0009] The active components loaded do not contain iron oxide. The inventors have conducted a large amount of research on the existing Claus tail gas incineration catalyst, and believe that the main chemical reaction substance for oxidizing hydrogen sulfide, organic sulfur and elemental sulfur to sulfur dioxide at 300-350 DEG C in the existing Claus tail gas incineration catalyst is chromium oxide, and iron oxide mainly plays a role in improving the dispersion of chromium oxide on conventional silica gel or silica-aluminum carriers. Chromium oxide cannot catalyze the deep oxidation of sulfur dioxide to sulfur trioxide, but iron oxide can deep-oxidize 2-10% of sulfur dioxide to sulfur trioxide. Based on this, the inventors propose a Claus tail gas incineration catalyst with high-purity and ultra-low-iron-impurity silica as a carrier to load active components scandium oxide and chromium oxide. In the catalyst, high-purity and ultra-low-iron-impurity silica is used as a carrier to replace conventional silica gel or silica-aluminum materials, eliminating the influence of the high-iron-impurity content of conventional silica gel or silica-aluminum materials on the catalyst, and scandium oxide is used to replace iron oxide, so that chromium oxide is uniformly dispersed on the high-purity and ultra-low-iron-impurity silica carrier while not catalyzing the deep oxidation of sulfur dioxide to sulfur trioxide. Under the cooperation of high-purity and ultra-low-iron-impurity silica, scandium oxide and chromium oxide, the catalyst can effectively catalyze the Claus tail gas incineration process while avoiding the generation of sulfur trioxide (a device with a detection lower limit of 1 ppm cannot detect the presence of sulfur trioxide).

[0010] According to the preferred embodiment of the first aspect, the content of scandium oxide is 0.5-0.8% and the content of chromium oxide is 3.0-4.5% by weight based on the total mass of the catalyst.

[0011] According to the preferred embodiment of the first aspect, the high-purity and ultra-low-iron-impurity-content silicon dioxide used as the carrier is obtained by tabletting high-purity and ultra-low-iron-impurity-content silicon dioxide powder.

[0012] Further, the high-purity and ultra-low-iron-impurity-content silicon dioxide powder has a specific surface area of 100-150 m 2 / g, an average particle size of 0.2-0.5 microns, and a bulk density of 0.1-0.15 g / ml.

[0013] Further, the tabletting pressure is 10-30 MPa and the punching time is 1-2 s.

[0014] Further, the high-purity and ultra-low-iron-impurity-content silicon dioxide powder is selected from hydrophilic high-purity and ultra-low-iron-impurity-content silicon dioxide powder produced by a vapor phase method.

[0015] According to the preferred embodiment of the first aspect, the high-purity and ultra-low-iron-impurity-content silicon dioxide used as the carrier is in the form of a tablet with a diameter of 8-10 mm and a height of 2-3 mm.

[0016] In a second aspect, the present application provides a preparation method of the Claus tail gas combustion catalyst as described above, wherein the method comprises:

[0017] The high-purity and ultra-low-iron-impurity-content silicon dioxide used as the carrier is immersed in a mixed solution of scandium salt and chromium salt, and then dried and calcined to obtain the catalyst.

[0018] According to the preferred embodiment of the second aspect, the method further comprises a carrier preparation step: high-purity and ultra-low-iron-impurity-content silicon dioxide powder with a specific surface area of 100-150 m 2 / g, an average particle size of 0.2-0.5 microns, and a bulk density of 0.1-0.15 g / ml is mixed with water and then tabletted, and then the tabletted product is dried to obtain high-purity and ultra-low-iron-impurity-content silicon dioxide in the form of a tablet with a diameter of 8-10 mm and a height of 2-3 mm as the carrier; wherein the tabletting pressure is 10-30 MPa and the punching time is 1-2 s.

[0019] Further, the mass ratio of the high-purity and ultra-low-iron-impurity-content silicon dioxide powder to water is 300-400:100-130.

[0020] Further, the temperature of drying is 120-130℃, and the time of drying is 2-3h.

[0021] According to the preferred embodiment of the second aspect, the scandium salt comprises scandium nitrate and / or scandium sulfate;

[0022] Further, the scandium salt is scandium nitrate.

[0023] According to the preferred embodiment of the second aspect, the chromium salt comprises one or more of chromium nitrate, chromium chloride and chromium sulfate;

[0024] Further, the chromium salt is chromium nitrate.

[0025] According to the preferred embodiment of the second aspect, the temperature of drying after impregnation is 100-110℃.

[0026] According to the preferred embodiment of the second aspect, the temperature of calcination is 350-400℃, and the time of calcination is 2-3h.

[0027] According to the preferred embodiment of the second aspect, the method comprises:

[0028] Preparation of the carrier: 300-400 parts by weight of high-purity and ultra-low-iron-impurity-content silicon dioxide powder with a specific surface area of 100-150 m 2 / g, an average particle size of 0.2-0.5 microns and a bulk density of 0.1-0.15 g / ml is mixed with 100-130 parts by weight of water to form a tablet by tablet molding with a molding pressure of 10-30 MPa and a punching time of 1-2 s, forming a tablet with a diameter of 8-10 mm and a height of 2-3 mm, and then drying the tablet-molded product at 120-130℃ to obtain the carrier;

[0029] Preparation of the impregnation solution: scandium salt (anhydrous scandium nitrate and / or scandium sulfate, purity >98%) and chromium salt (anhydrous chromium nitrate and / or chromium chloride and / or chromium sulfate, purity >99%) are mixed with water to obtain a mixed solution of scandium salt and chromium salt with a scandium salt volume concentration of 83-130 g / L and a chromium salt volume concentration of 470-705 g / L;

[0030] Impregnation: the carrier is immersed in the mixed solution of scandium salt and chromium salt; wherein the ratio of the amount of the carrier to the mixed solution of scandium salt and chromium salt is 40-50 g: 50-80 ml;

[0031] Drying: the product after impregnation is dried at 120-130℃;

[0032] Calcination: the product after drying is calcined at 350-400℃ for 2-3h to obtain the catalyst.

[0033] In a third aspect, the present application provides the use of the Claus tail gas combustion catalyst as described above as a catalyst in a Claus tail gas combustion process.

[0034] According to a preferred embodiment of the third aspect, in the use described above, the Claus tail gas is passed into a combustion device filled with the catalyst described above for combustion.

[0035] According to a preferred embodiment of the third aspect, in the use described above, the particle size of the catalyst is 1.5-2 mm.

[0036] According to a preferred embodiment of the third aspect, in the use described above, the gas space velocity is 1000-1500 h -1 .

[0037] According to a preferred embodiment of the third aspect, in the use described above, the combustion temperature is 300-350℃.

[0038] Compared with the prior art, the technical solution provided by the present application has the following beneficial effects:

[0039] 1. The existing Claus tail gas catalytic combustion catalyst can catalyze the side reaction of deep oxidation of sulfur dioxide into sulfur trioxide. The volume concentration of sulfur trioxide in the gas after combustion is about 100-200 ppm. The catalyst of the present application can effectively inhibit the generation of sulfur trioxide, and the volume concentration of sulfur trioxide in the gas after combustion is <1 ppm.

[0040] 2. The existing Claus tail gas catalytic combustion catalyst has poor oxidation effect on organic sulfur, and can only ensure that the concentration of organic sulfur in the gas after combustion is <20 ppm. The catalyst of the present application strengthens the oxidation effect of organic sulfur, and the concentration of organic sulfur in the gas after combustion is <5 ppm.

[0041] 3. Using the catalyst provided by the present application for Claus tail gas catalytic combustion can meet the requirement of <10 ppm of sulfur trioxide volume concentration proposed by the subsequent tail gas treatment process while inhibiting the generation of sulfur trioxide, solving the problems of serious device corrosion and a large amount of salt-containing wastewater, and the concentration of organic sulfur (COS) is far lower than <20 ppm, which reduces the concentration of sulfide in the device exhaust gas, and the environmental protection benefit is significant. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Flow chart for catalyst preparation in Example 1. DETAILED DESCRIPTION

[0043] For a more clear explanation of the present application, the present application is further described below in connection with preferred embodiments. It should be understood by those skilled in the art that the specific description given below is illustrative and not restrictive and should not be taken as limiting the scope of the present application. Efforts have been made to ensure accuracy with respect to numbers (e.g. amounts, temperatures, etc.) but some errors and deviations should be construed as being within the scope of the application.

[0044] Example 1

[0045] The present example provides a Claus tail gas combustion catalyst, which is prepared by the following method (flow as shown in Figure 1

[0046] 383g of high-purity and ultra-low-iron-impurity-containing silicon dioxide powder (model OX100 produced by Degussa Company in Germany, a hydrophilic silicon dioxide produced by a gas phase method, with a silicon dioxide weight percentage of 99.96%, an iron oxide weight percentage of 0.0042%, a specific surface area of 105m 2 / g, an average particle size of 0.33 microns, and a bulk density of 0.12g / ml) is weighed into a 5L beaker, and then 125g of distilled water is added to the 5L beaker and stirred and mixed for 2min with a glass rod;

[0047] The mixed product is transferred to a rotary tablet press for tablet molding, and then dried at 120°C for 3h to obtain a carrier; the molding uses an 8mm mold, the molding pressure is 16MPa, the punching time is 1.2s, and the molded tablet has a diameter of 8.1mm and a height of 2.4mm;

[0048] 97g of anhydrous scandium nitrate (purity 98.5%) and 559g of anhydrous chromium nitrate (purity 99.2%) are weighed into another 5L beaker, and 500g of distilled water is slowly added, and stirred slowly with a glass rod until completely dissolved, and continue to add distilled water to a total solution volume of 1L to obtain a mixed solution of scandium salt and chromium salt;

[0049] The dried carrier 42g is weighed into a 1L beaker; 55ml of the mixed solution of scandium salt and chromium salt is measured and poured into the above 1L beaker; the carrier is immersed in the mixed solution of scandium salt and chromium salt for 2h;

[0050] After the immersion is complete, the carrier is filtered out and placed for 10h and then dried at 105°C for 2h;

[0051] The dried product is calcined at 380°C for 3h to obtain a Claus tail gas combustion catalyst.

[0052] The weight percentage of scandium oxide in the catalyst product is 0.66%, and the weight percentage of chromium oxide is 4.05%.

[0053] ​The Claus tail gas combustion catalyst provided in the present embodiment is crushed to a particle size of 1.5-2 mm, 20 g of the particles are weighed and loaded into a fixed bed reactor of a catalyst activity evaluation device, a gas containing 1.5% by volume of hydrogen sulfide, 0.28% of organic sulfur (COS), 0.05% of elemental sulfur, 0.88% of sulfur dioxide, 3.8% of oxygen, and the balance of nitrogen is introduced, and combustion is carried out at 330°C; wherein the gas flow is 650 ml / min, the pressure (gauge pressure) is 15 kPa (the catalyst operating space velocity is converted to 1170 h -1 ). The volume content of hydrogen sulfide, COS and sulfur trioxide in the reactor outlet gas is analyzed, and the results are shown in Table 1. The volume concentration of hydrogen sulfide is 8.5 ppm, the volume concentration of COS is 2.6 ppm, and sulfur trioxide cannot be detected (the lower limit of the analysis detection is 1 ppm).

[0054] Example 2

[0055] The present embodiment provides a Claus tail gas combustion catalyst, which is prepared by the following method:

[0056] A 355 g of high-purity and ultra-low-iron-impurity-containing silicon dioxide powder (model A120 produced by Degussa Company in Germany, a hydrophilic silicon dioxide produced by a gas phase method, the weight percentage of silicon dioxide is 99.94%, the weight percentage of iron oxide is 0.0051%, the specific surface area is 121 m 2 / g, the average particle size is 0.26 microns, and the bulk density is 0.12 g / ml) is weighed into a 5 L beaker, and then 130 g of distilled water is added to the 5 L beaker and stirred and mixed with a glass rod for 3 min;

[0057] The mixed product is transferred to a rotary tablet press for tablet molding, and then dried at 130°C for 3 h to obtain a carrier; the molding uses a 10 mm mold, the molding pressure is 19 MPa, the punching time is 1.8 s, and the diameter of the molded sheet is 9.9 mm and the height is 2.5 mm;

[0058] 105 g of anhydrous scandium nitrate (purity 98.5%) and 641 g of anhydrous chromium nitrate (purity 99.2%) are weighed into another 5 L beaker, and 500 g of distilled water is slowly added, and the mixture is slowly stirred until completely dissolved, and distilled water is continuously added to a total solution volume of 1 L to obtain a mixed solution of scandium salt and chromium salt;

[0059] 48 g of the dried carrier is weighed into a 1 L beaker; 58 ml of the mixed solution of scandium salt and chromium salt is measured and poured into the above 1 L beaker; the carrier is immersed in the mixed solution of scandium salt and chromium salt for 3 h;

[0060] After the immersion is completed, the carrier is filtered out, placed for 10 h, and then dried at 110°C for 2 h;

[0061] The dried product was calcined at 370℃ for 3h to obtain a Claus tail gas combustion catalyst.

[0062] The weight percentage of scandium oxide in the catalyst product was 0.63%, and the weight percentage of chromium oxide was 3.82%.

[0063] The Claus tail gas combustion catalyst provided in the present embodiment was crushed to particles with a particle size of 1.5-2mm, and 20g of the particles were weighed and loaded into a fixed bed reactor of a catalyst activity evaluation device; a gas containing 1.7% by volume of hydrogen sulfide, 0.17% of organic sulfur (COS), 0.06% of elemental sulfur, 0.62% of sulfur dioxide, 3.9% of oxygen, and the balance being nitrogen was introduced, and combustion was carried out at 340℃; wherein the gas flow was 720ml / min, and the pressure (gauge pressure) was 18kPa (converted to the catalyst operating space velocity as 1340h-1). -1 The volume content of hydrogen sulfide, COS and sulfur trioxide in the reactor outlet gas was analyzed, and the results are shown in Table 1. The volume concentration of hydrogen sulfide was 8.7ppm, the volume concentration of COS was 3.4ppm, and sulfur trioxide could not be detected (the lower limit of the analysis detection was 1ppm).

[0064] Example 3

[0065] The present embodiment provides a Claus tail gas combustion catalyst, which is prepared by the following method:

[0066] 327g of high-purity and ultra-low-iron-impurity-containing silicon dioxide powder (model A120 produced by Degussa Company in Germany, a hydrophilic silicon dioxide produced by a gas phase method, with a weight percentage of 99.94% of silicon dioxide, a weight percentage of 0.0051% of iron oxide, a specific surface area of 121m 2 / g, an average particle size of 0.26 microns, and a bulk density of 0.12g / ml) was weighed into a 5L beaker, and then 124g of distilled water was added to the 5L beaker and stirred and mixed with a glass rod for 1min;

[0067] The mixed product was transferred to a rotary tablet press for tablet molding, and then dried at 130℃ for 3h to obtain a carrier; a 8mm mold was used for molding, the molding pressure was 12MPa, the punching time was 2.0s, and the diameter of the molded sheet was 8.2mm and the height was 2.2mm;

[0068] 92g of anhydrous scandium nitrate (purity 98.5%) and 505g of anhydrous chromium nitrate (purity 99.2%) were weighed into another 5L beaker, and 500g of distilled water was slowly added, and stirred slowly with a glass rod until completely dissolved, and distilled water was continuously added to a total solution volume of 1L to obtain a mixed solution of scandium salt and chromium salt;

[0069] The dried carrier 44 g was weighed into a 1 L beaker; 52 ml of the mixed solution of scandium salt and chromium salt was measured and poured into the 1 L beaker; the carrier was immersed in the mixed solution of scandium salt and chromium salt for 3 h;

[0070] After the immersion, the carrier was filtered out, placed for 10 h and then dried at 110 °C for 2 h;

[0071] The dried product was calcined at 395 °C for 3 h to obtain a Claus tail gas combustion catalyst.

[0072] The weight percentage of scandium oxide in the catalyst product was 0.51%, and the weight percentage of chromium oxide was 3.36%.

[0073] The Claus tail gas combustion catalyst provided in the example was crushed to a particle size of 1.5-2 mm, 20 g of the particles were weighed and loaded into a fixed bed reactor of a catalyst activity evaluation device; a gas containing 0.83% by volume of hydrogen sulfide, 0.09% of organic sulfur (COS), 0.08% of elemental sulfur, 0.83% of sulfur dioxide, 3.1% of oxygen, and the balance being nitrogen was introduced, and combustion was carried out at 335 °C; wherein the gas flow was 800 ml / min, and the pressure (gauge pressure) was 12 kPa (converted to the catalyst operating space velocity of 1480 h -1 ). The volume content of hydrogen sulfide, COS and sulfur trioxide in the reactor outlet gas was analyzed, and the results are shown in Table 1. The volume concentration of hydrogen sulfide was 6.2 ppm, the volume concentration of COS was 2.4 ppm, and sulfur trioxide could not be detected (the lower limit of the analysis detection was 1 ppm).

[0074] Example 4

[0075] The present example provides a Claus tail gas combustion catalyst, which is prepared by the following method:

[0076] 225 g of scandium sulfate octahydrate (purity 98.5%) and 993 g of chromium chloride hexahydrate (purity 99.1%) were weighed into a 5 L beaker, and 925 g of distilled water was slowly added, and stirred slowly with a glass rod until completely dissolved. Distilled water was continuously added until the total volume of the solution was 2 L, to obtain a mixed solution of scandium salt and chromium salt;

[0077] The dried carrier 48 g in Example 3 was weighed into a 1 L beaker; 55 ml of the mixed solution of scandium salt and chromium salt was measured and poured into the 1 L beaker; the carrier was immersed in the mixed solution of scandium salt and chromium salt for 3 h;

[0078] After the immersion, the carrier was filtered out, placed for 10 h and then dried at 110 °C for 2 h;

[0079] The dried product was calcined at 395 °C for 3 h to obtain a Claus tail gas combustion catalyst.

[0080] The weight percentage of scandium oxide in the catalyst product was 0.54%, and the weight percentage of chromium oxide was 3.03%.

[0081] The Claus tail gas combustion catalyst provided in this example was crushed into particles with a particle size of 1.5-2 mm, and 20 g of the particles were loaded into a fixed bed reactor of a catalyst activity evaluation device. A gas containing 0.83% by volume of hydrogen sulfide, 0.09% of organic sulfur (COS), 0.08% of elemental sulfur, 0.83% of sulfur dioxide, 3.1% of oxygen, and the balance nitrogen was introduced, and combustion was carried out at 335°C; wherein the gas flow was 800 ml / min, and the pressure (gauge pressure) was 12 kPa (the catalyst operating space velocity was converted to 1480 h -1 ). The volume concentration of hydrogen sulfide in the reactor outlet gas was 6.7 ppm, the volume concentration of COS was 4.3 ppm, and sulfur trioxide could not be detected (the lower limit of the analysis detection was 1 ppm).

[0082] Comparative Example 1

[0083] This comparative example provides a Claus tail gas combustion catalyst

[0084] The preparation method of the catalyst provided in this comparative example is different from that of Example 1 in that the carrier is silica gel, the diameter of the formed sheet is 8.5 mm, the height is 3.2 mm, and anhydrous ferric nitrate is used instead of anhydrous scandium nitrate.

[0085] The prepared catalyst has a weight percentage of 92.43% of silicon dioxide, a weight percentage of 3.76% of chromium oxide, and a weight percentage of 2.84% of iron oxide.

[0086] The catalyst provided in this comparative example was crushed into particles with a particle size of 1.5-2 mm, and 20 g of the particles were loaded into a fixed bed reactor of a catalyst activity evaluation device. A gas containing 1.5% by volume of hydrogen sulfide, 0.28% of organic sulfur (COS), 0.05% of elemental sulfur, 0.88% of sulfur dioxide, 3.8% of oxygen, and the balance nitrogen was introduced, and combustion was carried out at 330°C; wherein the gas flow was 650 ml / min, the gas pressure (gauge pressure) was 15 kPa, and the catalyst operating space velocity was converted to 1265 h -1 . The volume content of hydrogen sulfide, COS, and sulfur trioxide in the reactor outlet gas was analyzed, and the results are shown in Table 1. The volume concentration of hydrogen sulfide was 8.3 ppm, the volume concentration of COS was 17.64 ppm, and the volume concentration of sulfur trioxide was 157 ppm.

[0087] Comparative Example 2

[0088] This comparative example provides a Claus tail gas combustion catalyst

[0089] The preparation method of the catalyst provided by the comparative example is different from that of Example 1 in that the carrier is silica gel, and the diameter of the formed sheet is 8.5 mm and the height is 3.2 mm. The preparation method of the mixed solution of the scandium salt and the chromium salt, the carrier impregnation step, and the drying time are completely the same as those of Example 1;

[0090] The weight percentage of scandium oxide in the catalyst product is 0.43%, the weight percentage of chromium oxide is 2.66%, and the weight percentage of iron oxide is 0.08%.

[0091] The catalyst provided by the comparative example is crushed to particles with a particle size of 1.5-2 mm, and 20 g of the particles are loaded into a fixed bed reactor of a catalyst activity evaluation device. A gas containing 1.5% by volume of hydrogen sulfide, 0.28% of organic sulfur (COS), 0.05% of elemental sulfur, 0.88% of sulfur dioxide, 3.8% of oxygen, and the balance of nitrogen is introduced, and incineration is carried out at 330°C; wherein the gas flow is 650 ml / min, the gas pressure (gauge pressure) is 15 kPa, and the converted catalyst operating space velocity is 1265 h-1. -1 The volume contents of hydrogen sulfide, COS, and sulfur trioxide in the reactor outlet gas are analyzed, and the results are shown in Table 1. The volume concentration of hydrogen sulfide is 7.7 ppm, the volume concentration of COS is 12.3 ppm, and the volume concentration of sulfur trioxide is 85 ppm.

[0092] Comparative Example 3

[0093] The comparative example provides a Claus tail gas incineration catalyst

[0094] The preparation method of the catalyst provided by the comparative example is different from that of Example 1 in that anhydrous iron nitrate is used instead of anhydrous scandium nitrate to prepare the mixed solution. The carrier preparation and molding, the carrier impregnation step, and the drying time are completely the same as those of Example 1;

[0095] The weight percentage of chromium oxide in the catalyst product is 3.98%, and the weight percentage of iron oxide is 2.43%.

[0096] The catalyst provided by the comparative example is crushed to particles with a particle size of 1.5-2 mm, and 20 g of the particles are loaded into a fixed bed reactor of a catalyst activity evaluation device. A gas containing 1.5% by volume of hydrogen sulfide, 0.28% of organic sulfur (COS), 0.05% of elemental sulfur, 0.88% of sulfur dioxide, 3.8% of oxygen, and the balance of nitrogen is introduced, and incineration is carried out at 330°C; wherein the gas flow is 650 ml / min, the gas pressure (gauge pressure) is 15 kPa, and the converted catalyst operating space velocity is 1265 h-1. -1 The volume contents of hydrogen sulfide, COS, and sulfur trioxide in the reactor outlet gas are analyzed, and the results are shown in Table 1. The volume concentration of hydrogen sulfide is 6.4 ppm, the volume concentration of COS is 19.3 ppm, and the volume concentration of sulfur trioxide is 255 ppm.

[0097] Table 1

[0098]

[0099] As shown in Table 1, the catalyst of the present application can effectively inhibit the generation of sulfur trioxide, and the volume concentration of sulfur trioxide in the incineration gas is less than 1 ppm, and the oxidation effect on organic sulfur is excellent, and the concentration of organic sulfur in the incineration gas is less than 5 ppm, and the environmental protection benefit is remarkable.

[0100] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. For those skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made, and it is impossible to enumerate all the implementation modes here. Any changes or variations derived from the technical solutions of the present application still fall within the protection scope of the present application.

Claims

1. A Claus tail gas combustion catalyst, wherein, The catalyst is loaded with active components scandium oxide and chromium oxide on a carrier of high-purity and ultra-low iron impurity content silicon dioxide; The high-purity and ultra-low iron impurity content silicon dioxide contains >99.9% silicon dioxide and <0.01% iron oxide, based on the total mass of the high-purity and ultra-low iron impurity content silicon dioxide. The loaded active components do not contain iron oxide.

2. The catalyst of claim 1, wherein, The amount of scandium oxide is 0.5-0.8% and the amount of chromium oxide is 3.0-4.5%, based on the total mass of the catalyst.

3. The catalyst of claim 1, wherein, The high-purity and ultra-low iron impurity content silicon dioxide used as the carrier is obtained by tabletting high-purity and ultra-low iron impurity content silicon dioxide powder; wherein the specific surface of the silicon dioxide powder of high purity and ultra-low iron impurity content is 100-150 m 2 / g, the average particle size is 0.2-0.5 microns, and the bulk density is 0.1-0.15 g / ml; The tabletting pressure is 10-30 MPa and the tabletting time is 1-2 s.

4. The catalyst of claim 1, wherein, The high-purity and ultra-low iron impurity content silicon dioxide used as the carrier is in the form of tablets with a diameter of 8-10 mm and a height of 2-3 mm.

5. The method of making a Claus tail gas combustion catalyst according to any one of claims 1 to 4, wherein, The method comprises: The high-purity and ultra-low iron impurity content silicon dioxide used as the carrier is immersed in a mixed solution of scandium salt and chromium salt, and then dried and calcined to obtain the catalyst.

6. The method of claim 5, wherein, The preparation method further comprises a carrier preparation step: high-purity and ultra-low-iron-silica powder having a specific surface of 100-150 m 2 / g, an average particle size of 0.2-0.5 microns, and a bulk density of 0.1-0.15 g / ml is mixed with water, and then tableting is performed to form a product, which is then dried to obtain a high-purity and ultra-low-iron-silica powder in the form of a tablet having a diameter of 8-10 mm and a height of 2-3 mm as a carrier; The tabletting pressure is 10-30 MPa and the tabletting time is 1-2 s.

7. The method of claim 6, wherein, The mass ratio of high-purity and ultra-low iron impurity content silicon dioxide powder to water is 300-400:100-130.

8. The method of claim 6, wherein, During the drying process of the tabletted product, the drying temperature is 120-130°C and the drying time is 2-3 h.

9. The preparation method of claim 6, wherein The scandium salt comprises scandium nitrate and / or scandium sulfate; The chromium salt comprises one or more than two combinations of chromium nitrate, chromium chloride and chromium sulfate.

10. The method of claim 5, wherein, The drying temperature after the immersion is 100-110°C.

11. The method of claim 5, wherein, The calcination temperature is 350-400°C and the calcination time is 2-3 h.

12. Use of the catalyst of any one of claims 1-4 as a catalyst in a Claus tail gas combustion process.

13. Use according to claim 12, wherein, In the above use, the Claus tail gas is fed into a combustion device filled with the catalyst of any one of claims 1-4 for combustion; The particle size of the catalyst is 1.5-2 mm. wherein the gas space velocity of the claus tail gas is 1000-1500 h -1 ; The combustion temperature is 300-350°C.

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