Impregnation liquid and preparation method thereof, catalyst and preparation method and application thereof, and alkane dehydrogenation method
阅读说明：本技术 浸渍液及其制备方法和催化剂及其制备方法和应用及烷烃脱氢的方法 (Impregnation liquid and preparation method thereof, catalyst and preparation method and application thereof, and alkane dehydrogenation method ) 是由 洪学思 缪长喜 吴省 吴文海 于 2019-09-20 设计创作，主要内容包括：本发明涉及烷烃脱氢领域,公开了浸渍液及其制备方法和催化剂及其制备方法和应用及烷烃脱氢的方法,该浸渍液包括：含铬化合物、含A元素化合物、含B元素化合物、溶剂以及分散剂；所述A元素选自IIIB族、IVB和VB族元素中的至少一种,所述B元素选自IA族元素中的至少一种；所述浸渍液的表面张力为45-75mN/m。采用本发明提供的浸渍液制得的催化剂,抗积碳能力强,催化剂的稳定性好且产品收率高。(The invention relates to the field of alkane dehydrogenation, and discloses an impregnating solution, a preparation method thereof, a catalyst, a preparation method and application thereof, and an alkane dehydrogenation method, wherein the impregnating solution comprises the following components: chromium-containing compound, A element-containing compound, B element-containing compound, solvent and dispersant; the A element is selected from at least one of IIIB group, IVB group and VB group elements, and the B element is selected from at least one of IA group elements; the surface tension of the impregnation liquid is 45-75 mN/m. The catalyst prepared by the impregnation liquid provided by the invention has strong anti-carbon deposition capability, good stability and high product yield.)
1. An impregnation fluid, comprising: chromium-containing compound, A element-containing compound, B element-containing compound, solvent and dispersant;
wherein the A element is selected from at least one of IIIB group, IVB group and VB group elements, and the B element is selected from at least one of IA group elements;
wherein the surface tension of the immersion liquid is 45-75mN/m, preferably 50-65 mN/m.
2. The immersion liquid according to claim 1, wherein the content of the chromium-containing compound is 3.85X 10 in terms of chromium element-4To 9.63X 10-4mol/ml, preferably 4.82X 10-4To 8.67X 10-4mol/ml, more preferably 5.78X 10-4To 7.7X 10-4mol/ml；
Preferably, the chromium-containing compound is selected from at least one of nitrates, oxides, sulfates, oxalates, chromates, and citrates of the chromium element.
3. The impregnation solution according to claim 1, wherein the content of the compound containing the element A is 0.8 x 10 in terms of the element A- 4mol/ml or more, preferably 1X 10-4To 5X 10-4mol/ml, more preferably 1.5X 10-4To 3X 10-4mol/ml；
Preferably, the element a is selected from at least one of the elements zirconium, titanium, vanadium, yttrium, scandium, and niobium;
preferably, the compound containing the element A is selected from soluble salts of the element A, and further preferably at least one of nitrate, chloride, oxysulfate and sulfate.
4. The impregnation solution according to claim 1, wherein the content of the compound containing the B element is 0.8X 10 in terms of the B element- 4mol/ml or more, preferably 1X 10-4To 5X 10-4mol/ml, more preferably 1.5X 10-4To 3X 10-4mol/ml；
Preferably, the B element is sodium and/or potassium element;
preferably, the compound containing the element B is selected from at least one of nitrate, chloride and sulfate of the element B.
5. The impregnation solution according to any one of claims 1 to 4, wherein the dispersing agent is an organic acid, preferably at least one selected from the group consisting of citric acid, acetic acid, oxalic acid and benzoic acid, preferably citric acid;
preferably, the content of the dispersant is 1 × 10-4To 50X 10-4mol/ml, preferably 2X 10-4To 10X 10-4mol/ml；
Preferably, the pH of the impregnation solution is 0.1 to 4, preferably 0.5 to 3, more preferably 1 to 2.
6. A method of preparing an impregnation fluid according to any one of claims 1 to 5, which method comprises:
mixing a chromium-containing compound, an element A-containing compound, an element B-containing compound, a solvent and an optional dispersant;
preferably, the method comprises:
a) firstly mixing a chromium-containing compound, an element A-containing compound, an element B-containing compound and at least part of a solvent to obtain a first solution;
b) the first solution and the dispersant and optionally a portion of the solvent are subjected to a second mixing.
7. The production method according to claim 6, wherein the conditions of the first mixing include: performing ultrasonic treatment at 40-60 deg.C for 0.5-2 h;
preferably, the conditions of the second mixing include: ultrasonic treating at 30-70 deg.C for 0.2-1.5 hr, preferably at 40-60 deg.C for 0.5-1 hr.
8. A method of preparing a catalyst, the method comprising: impregnating a carrier with the impregnation liquid according to any one of claims 1 to 5, and then calcining the impregnated solid product.
9. The method of claim 8, wherein the support is a refractory inorganic oxide and/or a molecular sieve;
preferably, the carrier is selected from at least one of molecular sieves, alumina, silica, magnesia, titania and zirconia;
preferably, the impregnation solution and the carrier are used in amounts such that the resulting catalyst has a Cr content of 10 to 30 wt.%, preferably 15 to 25 wt.%, calculated as chromium oxide, based on the total amount of the catalyst.
10. A catalyst made by the process of claim 8 or 9.
11. Use of the catalyst of claim 10 in the dehydrogenation of alkanes.
12. A process for the dehydrogenation of an alkane, the process comprising: contacting an alkane with the catalyst of claim 10 under catalytic dehydrogenation conditions;
preferably, the conditions of the catalytic dehydrogenation include: the temperature is 500 ℃ and 700 ℃, and the mass space velocity of the alkane is 0.5-5h-1The pressure is 0.05-0.15MPa in terms of gauge pressure;
preferably, the alkane contains less than 6 carbon atoms, and further preferably, the alkane is at least one of propane, butane and isobutane.
Technical Field
The invention relates to the field of alkane dehydrogenation, in particular to an impregnating solution, a preparation method thereof, a catalyst, a preparation method and application thereof, and an alkane dehydrogenation method.
Background
Lower alkanes primarily refer to alkanes containing less than 6 carbon atoms. The preparation of low-carbon olefin from low-carbon alkane is the hot spot of industrial research at present. Propylene and isobutene are basic organic chemical raw materials widely applied to low-carbon olefins, have wide application and are important basic raw materials in modern petrochemical industry. Propylene is mainly used for producing polypropylene, and is also used for producing various important organic synthesis intermediates such as acrylonitrile, propylene oxide, acrylic acid, isopropanol and the like, and isobutene is mainly used for synthesizing products such as butyl rubber, polyisobutylene, methacrylonitrile, methyl tert-butyl ether and the like. Most of propylene and isobutene are obtained as byproducts from oil refining, but because petroleum reserves are limited, the propylene and the isobutene are limited by raw material sources and large-scale increase of yield is difficult, so that new routes for preparing low-carbon olefins such as propylene and isobutene are vigorously developed in various countries in the world, and particularly a method for preparing the low-carbon olefins by taking low-carbon alkanes as raw materials to perform dehydrogenation reaction is adopted.
Currently, the main research direction of low-carbon dehydrogenation includes the preparation of high-performance catalysts, and the impregnation method is a method commonly used in the preparation process of the catalysts, namely, required active components are loaded on the surface of a carrier through an impregnation solution. For example:
CN104998696A discloses an impregnation solution, its preparation and application, said impregnation solution contains cobalt-containing compound, molybdenum-containing compound, phosphorus-containing compound and citric acid. Wherein the concentration of the cobalt-containing compound is 0.01-0.1g/ml, the concentration of the molybdenum-containing compound is 0.05-0.4g/ml, the concentration of the phosphorus-containing compound is 0.005-0.10g/ml, the concentration of the citric acid is 0.05-0.5g/ml, and the ratio of the height of the peak at 517 +/-10 nm to the height of the peak at 772 +/-10 nm is less than or equal to 1 by ultraviolet-visible spectrum analysis.
CN102284295A discloses an impregnation solution of a hydrogenation catalyst and a method for preparing the hydrogenation catalyst, wherein the impregnation solution contains water-soluble IVB group metal compound, water-soluble organic acid salt of VIII group metal and water-soluble organic additive. Also provided is a preparation method of the hydrogenation catalyst, which comprises the steps of contacting the catalyst carrier with an impregnation solution of the hydrogenation catalyst and then drying. The prepared hydrogenation catalyst has obviously improved hydrogenation catalytic activity on heavy aromatics.
CN104307577A discloses an active dipping solution and a preparation method thereof, wherein the active dipping solution contains 1-5 wt% of penetration enhancer; 1-5 wt% of emulsifier; 0.2-10 wt% of surfactant; 1-10 wt% of ammonium paratungstate; 1 wt% -10 wt% of ammonium heptamolybdate; the balance of deionized water and acid; the cosolvent is acetamide. The impregnation solution has a good effect of supplementing the active ingredients of the SCR denitration catalyst, and the activity recovery rate of the supplemented SCR denitration catalyst is high.
CN107486216A discloses a preparation method of impregnation solution and the impregnation solution prepared by the method, the method comprises: (1) preparing a first solution containing at least one group VIII metal-containing compound and at least one first group VIB metal-containing compound; (2) activating the first solution at a pressure of more than 0.1MPa to less than or equal to 10MPa at 65-200 ℃ for 0.5-36 hours; (3) and after the temperature of the activated first solution is reduced to room temperature-50 ℃, introducing at least one compound containing a second VIB group metal into the first solution to obtain the impregnation solution. The hydrogenation catalyst prepared by using the dipping solution to dip the carrier has obviously improved hydrofining or hydrotreating performance.
CN108236962A discloses a preparation method of a low viscosity impregnation solution and a preparation method of a hydrogenation catalyst, the preparation method comprises (1) adding a phosphorus-containing compound, a molybdenum-containing compound and a nickel-containing compound into an aqueous solution of methanol; preparing a mixed solution; (2) stirring, heating and cooling, continuously adding a complexing agent or organic acid (3), stirring and dissolving, and continuously adding a nickel-containing compound; (4) stirring, heating and cooling, adding alkaline reagent to adjust pH of the mixed solution to 2-6, and concentrating to obtain the impregnation solution. The preparation method has the advantages of simple preparation, extremely high metal utilization rate and low cost, and the hydrogenation catalyst obtained by dipping the dipping solution has higher activity and activity stability.
When the impregnation solution containing the components is used for preparing the catalyst, the performance of the catalyst is improved, but the impregnation solution is not necessarily suitable for the low-carbon alkane dehydrogenation catalyst. At present, the main research on dehydrogenation of light alkanes is still focused on process development and high-performance catalyst development, and the traditional catalyst development is mainly focused on chromium-based and platinum-based catalysts, but at present, the research on the adoption of an impregnation solution taking Cr as an active component is insufficient, and the defects of poor catalyst stability and low product yield exist.
Disclosure of Invention
The invention aims to overcome the problems of poor stability of a catalyst in alkane dehydrogenation reaction and further improvement of product yield in the prior art, and provides an impregnation liquid and a preparation method thereof, a catalyst and a preparation method thereof, application of the catalyst and an alkane dehydrogenation method. The catalyst prepared by the impregnation liquid provided by the invention has strong anti-carbon deposition capability, good stability and high product yield.
In order to achieve the above object, a first aspect of the present invention provides an impregnation fluid comprising: chromium-containing compound, A element-containing compound, B element-containing compound, solvent and dispersant;
wherein the A element is selected from at least one of IIIB group, IVB group and VB group elements, and the B element is selected from at least one of IA group elements;
wherein the surface tension of the impregnation liquid is 45-75 mN/m.
Preferably, the surface tension of the impregnation liquid is 50-65 mN/m.
Preferably, the chromium-containing compound is contained in an amount of 3.85X 10 in terms of chromium element-4To 9.63X 10-4mol/ml, preferably 4.82X 10-4To 8.67X 10-4mol/ml, more preferably 5.78X 10-4To 7.7X 10-4mol/ml。
Preferably, the content of the compound containing the element A is 0.8X 10 in terms of the element A-4mol/ml or more, preferably 1X 10-4To 5X 10-4mol/ml, furtherThe step is preferably 1.5X 10-4To 3X 10-4mol/ml。
Preferably, the content of the compound containing B element is 0.8X 10 in terms of B element-4mol/ml or more, preferably 1X 10-4To 5X 10-4mol/ml, more preferably 1.5X 10-4To 3X 10-4mol/ml。
Preferably, the pH of the impregnation solution is 0.1 to 4, preferably 0.5 to 3, more preferably 1 to 2.
The second aspect of the present invention provides a method for preparing the impregnation fluid, including:
mixing a chromium-containing compound, an element A-containing compound, an element B-containing compound, a solvent and an optional dispersant.
Preferably, the method comprises:
a) firstly mixing a chromium-containing compound, an element A-containing compound, an element B-containing compound and at least part of a solvent to obtain a first solution;
b) the first solution and the dispersant and optionally a portion of the solvent are subjected to a second mixing.
In a third aspect, the present invention provides a method for preparing a catalyst, the method comprising: and (3) impregnating the carrier by adopting the impregnation liquid, and roasting a solid product obtained by impregnation.
In a fourth aspect, the present invention provides a catalyst prepared by the above method.
A fifth aspect of the invention provides the use of a catalyst as described above in the dehydrogenation of an alkane.
In a sixth aspect, the present invention provides a process for the dehydrogenation of an alkane, the process comprising: under catalytic dehydrogenation conditions, an alkane is contacted with the above-described catalyst provided by the present invention.
The impregnation liquid provided by the invention adopts chromium as an active component, and is matched with the element A and the element B for use, the catalyst prepared by the impregnation liquid is applied to alkane dehydrogenation, the stability of the catalyst is good, and the product yield is high. In particular, the inventor of the invention finds that the catalyst provided by the invention has better effect in the dehydrogenation reaction of low-carbon alkane with less than 6 carbon atoms, especially propane. In the embodiment of the invention, the carbon deposition rate on the catalyst after the propane dehydrogenation reaction is taken as an evaluation standard for the stability of the catalyst, and the lower the carbon deposition rate is, the stronger the carbon deposition resistance of the catalyst is, and the higher the stability is; the product yield of the catalyst was evaluated on the yield of propylene after the catalytic propane dehydrogenation reaction. As can be seen from the results of the examples of the invention, after the propane dehydrogenation reaction is carried out for 3 hours, the carbon deposition rate on the catalyst can be reduced to below 7 percent; the yield of propylene can reach 41.85 percent.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The first aspect of the present invention provides an impregnation fluid comprising: chromium-containing compound, A element-containing compound, B element-containing compound, solvent and dispersant;
wherein the A element is selected from at least one of IIIB group, IVB group and VB group elements, and the B element is selected from at least one of IA group elements;
wherein the surface tension of the impregnation liquid is 45-75 mN/m.
According to a preferred embodiment of the invention, the surface tension of the impregnation solution is between 50 and 65 mN/m. The impregnation liquid adopting the preferred embodiment is more beneficial to preparing the catalyst with better catalytic performance. In the present invention, the surface tension of the impregnation fluid may be measured by a surface tension meter.
According to the immersion liquid provided by the invention, preferably, the content of the chromium-containing compound is 3.85 × 10 in terms of chromium element-4To 9.63X 10-4mol/ml, preferably 4.82X 10-4To 8.67X 10-4mol/ml, more preferably 5.78X 10-4To 7.7X 10-4mol/ml, e.g. 5.78X 10-4mol/ml、5.98×10-4mol/ml、6.08×10-4mol/ml、6.18×10-4mol/ml、6.28×10-4mol/ml、6.5×10-4mol/ml、6.8×10-4mol/ml、7.0×10-4mol/ml、7.2×10-4mol/ml、7.5×10-4mol/ml、7.7×10-4mol/ml, and any value in the range of any two of these values.
In the present invention, the unit mol/ml of the component content indicates the number of moles of the specific component per ml of the impregnation solution, unless otherwise specified. For example, the content of the chromium-containing compound is 4.82X 10 in terms of chromium element-4To 8.67X 10- 4Expressed in mol/ml, 4.82X 10/ml of impregnation solution-4-8.67×10-4The chromium-containing compound is calculated by the mol of chromium element.
The specific kind of the chromium-containing compound is selected from a wide range so as to provide chromium element and not separate out in the content range, and specifically, the chromium-containing compound can be at least one of soluble chromium salt, chromium oxide and chromium hydroxide. The solubility means that the compound can be directly dissolved in a solvent or can be dissolved in the solvent under the action of a dispersing agent. Preferably, the chromium-containing compound is selected from at least one of nitrates, oxides, sulfates, oxalates, chromates, and citrates of the chromium element.
According to a preferred embodiment of the present invention, the content of the compound containing the element A is 0.8X 10 in terms of the element A- 4mol/ml or more, preferably 1X 10-4To 5X 10-4mol/ml, more preferably 1.5X 10-4To 3X 10-4mol/ml, e.g. 1.5X 10-4mol/ml、1.7×10-4mol/ml、1.8×10-4mol/ml、1.9×10-4mol/ml、2.0×10- 4mol/ml、2.2×10-4mol/ml、2.5×10-4mol/ml、2.8×10-4mol/ml、3.0×10-4mol/ml, and any value in the range of any two of these values.
Preferably, the element a is selected from at least one of the elements zirconium, titanium, vanadium, yttrium, scandium, and niobium, and more preferably at least one of the elements zirconium, titanium, and scandium.
The specific type of the compound containing the element A is selected from a wide range, so that the element A can be provided and the compound containing the element A is not precipitated in the content range, and specifically, the compound containing the element A can be at least one of soluble salt, oxide and hydroxide of the element A. Preferably, the A element-containing compound is selected from at least one of nitrate, chloride and sulfate of the A element, and is further preferably nitrate of the A element.
According to a preferred embodiment of the present invention, the content of the compound containing B element is 0.8X 10 in terms of B element- 4mol/ml or more, preferably 1X 10-4To 5X 10-4mol/ml, more preferably 1.5X 10-4To 3X 10-4mol/ml, e.g. 1.5X 10-4mol/ml、1.7×10-4mol/ml、1.8×10-4mol/ml、1.9×10-4mol/ml、2.0×10- 4mol/ml、2.2×10-4mol/ml、2.5×10-4mol/ml、2.8×10-4mol/ml、3.0×10-4mol/ml, and any value in the range of any two of these values.
Preferably, the B element is a sodium and/or potassium element, and more preferably a potassium element.
Preferably, the compound containing the element B is at least one selected from nitrate, chloride and sulfate of the element B, preferably sodium nitrate and/or potassium nitrate, and more preferably potassium nitrate.
According to the immersion liquid provided by the invention, the dispersing agent is used for dissolving more chromium-containing compounds, A element-containing compounds and B element-containing compounds in the solvent.
The dispersant of the invention has a wide selection range, and substances which can enable the chromium-containing compound, the element A-containing compound and the element B-containing compound with the contents to be dissolved in the solvent can be used as the dispersant of the invention. Preferably, the dispersant is an acid, more preferably an organic acid, further preferably at least one of citric acid, acetic acid, oxalic acid and benzoic acid, and particularly preferably citric acid.
According to a preferred embodiment of the invention, the content of the dispersant is 1 × 10-4To 50X 10-4mol/ml, preferably 2X 10-4To 10X 10-4mol/ml。
According to the invention, the solvent is preferably water, which may be, for example, deionized water, distilled water or pure water, preferably deionized water.
According to the invention, the pH of the impregnation solution is preferably 0.1 to 4, preferably 0.5 to 3, more preferably 1 to 2.
In the present invention, the method for producing the impregnation liquid is not particularly limited as long as the impregnation liquid can be obtained. The second aspect of the present invention provides a method for preparing the impregnation fluid, including:
mixing a chromium-containing compound, an element A-containing compound, an element B-containing compound, a solvent and a dispersant.
In the present invention, the specific embodiment of mixing the chromium-containing compound, the element a-containing compound, the element B-containing compound, the solvent, and the dispersant is not particularly limited as long as the chromium-containing compound, the element a-containing compound, and the element B-containing compound can be dissolved in the solvent.
In order to further improve the performance of the impregnation fluid, preferably, the preparation method of the impregnation fluid comprises the following steps:
a) firstly mixing a chromium-containing compound, an element A-containing compound, an element B-containing compound and at least part of a solvent to obtain a first solution;
b) the first solution and the dispersant and optionally a portion of the solvent are subjected to a second mixing.
The terms "first" and "second" in the present invention do not limit the technical solution of the present invention, but are only used to distinguish operations performed at different stages or added substances.
The ratio of the solvent used in step a) to the solvent used in step b) is not particularly limited in the present invention, and specifically, when a part of the solvent is added in step a), the remaining part of the solvent is added in step b), and when the whole solvent is added in step a), the solvent is not added in step b).
Preferably, the preparation method of the impregnation liquid comprises the following steps:
a) carrying out first mixing on a chromium-containing compound, an element A-containing compound, an element B-containing compound and a part of solvent to obtain a first solution;
b) and carrying out second mixing on the first solution, the dispersing agent and the rest part of the solvent.
The adoption of the preferred embodiment is more beneficial to the quantification of the impregnation liquid and the preparation of the subsequent catalyst.
According to a preferred embodiment of the present invention, the first mixing is performed under ultrasonic conditions, further preferably, the conditions of the first mixing include: ultrasonic treating at 40-60 deg.C for 0.5-2 hr.
According to a preferred embodiment of the present invention, the second mixing is performed under ultrasonic conditions, further preferably, the conditions of the second mixing include: ultrasonic treating at 30-70 deg.C for 0.2-1.5 hr, preferably at 40-60 deg.C for 0.5-1 hr.
In a third aspect, the present invention provides a method for preparing a catalyst, the method comprising: and (3) impregnating the carrier by adopting the impregnation liquid, and roasting a solid product obtained by impregnation.
The impregnation method of the present invention is widely selected, and various impregnation methods conventionally used in the art may be used, for example, saturation impregnation or supersaturation impregnation may be used. Specific embodiments of the saturated impregnation and the highly saturated impregnation may be performed according to the means conventional in the art.
According to the present invention, preferably, the impregnation conditions include: the temperature is 20-100 deg.C, and the time is 0.5-10 hr, preferably 40-80 deg.C, and the time is 2-6 hr.
According to the present invention, preferably, the carrier is a refractory inorganic oxide and/or a molecular sieve, more preferably at least one of a molecular sieve, alumina, silica, magnesia, titania and zirconia, and more preferably alumina and/or silica.
According to the invention, the impregnation solution and the support are preferably used in such amounts that the resulting catalyst has a Cr content of 10 to 30 wt.%, preferably 15 to 25 wt.%, calculated as chromium oxide on the total amount of the catalyst. On the basis of the present invention, the skilled person will know how to prepare a catalyst giving a Cr content in a specific range.
According to the present invention, preferably, the conditions of the firing include: the temperature is 300 ℃ and 900 ℃ and the time is 1-8 hours.
The method according to the invention may further comprise: the impregnated product is dried prior to the calcination. The drying can be carried out according to the conditions customary in the art, for example at a drying temperature of from 90 ℃ to 150 ℃ for a drying time of from 6 to 18 hours.
In a fourth aspect, the present invention provides a catalyst prepared by the above method.
The catalyst provided by the invention is used in alkane dehydrogenation reaction, and has the advantages of high product yield and good stability. Based on this, a fifth aspect of the invention provides the use of the above catalyst in the dehydrogenation of alkanes.
In a sixth aspect, the present invention provides a process for the dehydrogenation of an alkane, the process comprising: under catalytic dehydrogenation conditions, an alkane is contacted with the catalyst provided by the invention.
In the present invention, the alkane may be any alkane that can be treated by a catalytic dehydrogenation process. The invention has wide selection range of the composition and the content of the alkane, and the alkane can be a pure component or a mixture. During research, the inventors of the present invention found that the catalyst provided by the present invention is particularly suitable for dehydrogenation of alkanes with less than 6 carbon atoms.
Preferably, the alkane contains less than 6 carbon atoms, and further preferably, the alkane is at least one of propane, butane and isobutane. In the examples of the present invention and comparative examples, the dehydrogenation reaction of propane in a reactor is exemplified, and the present invention is not limited thereto.
Specifically, the contacting may be carried out at a temperature greater than 500 ℃ and the alkane is contacted with a catalyst to produce an alkene having the same number of carbon atoms and a byproduct by catalytic dehydrogenation, wherein the byproduct comprises hydrogen and at least one of the alkane and the alkene having a number of carbon atoms lower than that of the alkane.
According to a preferred embodiment of the invention, the conditions of the catalytic dehydrogenation comprise: the temperature is 500 ℃ and 700 ℃, and the mass space velocity of the alkane is 0.5-5h-1The pressure is 0.05-0.15MPa in terms of gauge pressure.
The present invention will be described in detail below by way of examples.
The surface tension of the impregnation liquids of the following examples and comparative examples was measured using a fully automatic surface tensiometer model K100 from KRUSS, germany. The test conditions for surface tension include: 30mL of the solution was poured into a measuring beaker at 20 ℃ at a distance of about 1.5 to 2.5mm from the platinum plate for a measuring time of 60 seconds.
Example 1
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of oxalic acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping fluid S1. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
an alumina carrier (a P200 type product commercially available from Sasol corporation, the same applies hereinafter) was impregnated with the impregnation liquid S1 at 80 ℃ for 4 hours, and then dried at 120 ℃ for 12 hours and calcined at 700 ℃ for 2 hours, to obtain the catalyst S1 having a Cr content of 20 wt% based on chromium sesquioxide.
Example 2
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of benzoic acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S2. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S2 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S2 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 3
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S3. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S3 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S3 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 4
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S4. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S4 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S4 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 5
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S5. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S5 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S5 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 6
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S6. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by impregnating solution S6 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S6 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 7
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S7. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S7 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S7 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 8
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S8. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S8 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S8 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 9
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 50 ℃ for 0.75h to obtain a steeping liquor S9. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S9 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S9 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 10
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of ammonium vanadate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S10. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S10 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S10 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 11
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of scandium chloride into 30ml of deionized water, and carrying out ultrasonic treatment for 1h at 50 ℃ to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S11. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S11 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S11 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Example 12
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate, a certain amount of potassium nitrate and a certain amount of titanyl sulfate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of citric acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain a steeping liquor S12. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnating solution S12 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst S12 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Comparative example 1
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of oxalic acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain an impregnation liquid D1. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnation liquid D1 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst D1 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Comparative example 2
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate and a certain amount of potassium nitrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of oxalic acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain an impregnation liquid D2. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnation liquid D2 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst D2 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Comparative example 3
Preparation of the impregnation liquid:
a) putting a certain amount of chromium nitrate nonahydrate and a certain amount of zirconium nitrate trihydrate into 30ml of deionized water, and carrying out ultrasonic treatment at 50 ℃ for 1h to obtain a solution 1;
b) adding a certain amount of oxalic acid into the solution 1, adding deionized water until the volume of the solution is 50ml, and performing ultrasonic treatment at 30 ℃ for 0.2h to obtain an impregnation liquid D3. The composition of the impregnation solution and the characterization data are shown in table 1.
Preparation of the catalyst:
the alumina carrier is impregnated by the impregnation liquid D3 for 4h at 80 ℃, then dried for 12h at 120 ℃, and calcined for 2h at 700 ℃, thus obtaining the catalyst D3 with the Cr content of 20 weight percent calculated by chromium sesquioxide.
Test example 1
Under the same conditions, catalysts S1-S12 and catalysts D1-D3 were subjected to catalytic reaction performance evaluation in an isothermal fixed bed reactor, and the reaction results are shown in Table 1. In the experimental examples, propane was contacted with a catalyst to perform catalytic dehydrogenation, and the process conditions evaluated included: the reaction pressure is normal pressure, the temperature is 600 ℃, and the mass space velocity of propane is 1h-1The reaction time is 3 h.
Wherein, the carbon deposition rate is calculated according to the following formula:
TABLE 1
Note: in Table 1, the content units of Cr, A element, B element and dispersant are all 10-4mol/ml。
The results in table 1 show that when the catalyst provided by the invention is used for propane dehydrogenation, the carbon deposition rate of the catalyst is significantly reduced, the carbon deposition rate in example 9 is as low as 0.8%, and the carbon deposition resistance of the catalyst is greatly improved, i.e., the stability of the catalyst is significantly improved when the catalyst provided by the invention is used for alkane dehydrogenation; after the catalyst prepared by the impregnation liquid provided by the invention is used for propane dehydrogenation reaction, the yield of propylene in the product can reach 41.85% to the maximum extent, so that the catalyst provided by the invention has high product yield.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
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