Propane dehydrogenation catalyst, preparation method thereof and propylene production method

Abstract

The invention relates to a propane dehydrogenation catalyst, a preparation method thereof and a method for producing propylene. The catalyst contains a carrier, an active component, a first auxiliary agent, a second auxiliary agent and a third auxiliary agent, the carrier is a composite oxide containing silicon dioxide, the active component contains a gallium element, the first auxiliary agent contains a group VIII noble metal element, the second auxiliary agent contains an alkali metal element and / or an alkaline earth metal element, and the third auxiliary agent contains a lanthanide metal element. The third aid is added, so that platinum can be kept in an atomic-scale dispersion state on the catalyst, the platinum is not easy to agglomerate during propane dehydrogenation reaction, and the propane dehydrogenation catalyst has higher propane conversion rate, propylene selectivity and yield.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a propane dehydrogenation catalyst and a preparation method thereof and a method for producing propylene. Background Art

[0002] Propylene is an important organic basic chemical raw material, widely used in the production of polypropylene, acetone, acrylonitrile, propylene oxide, acrylic acid and other chemical products. In recent years, with the development of the economy, the demand for propylene downstream products has gradually increased, greatly promoting the demand for propylene. However, traditional propylene production processes such as naphtha cracking and catalytic cracking are difficult to keep up with the growing demand for propylene. As shale gas development provides abundant propane supply, the propane direct dehydrogenation to propylene (PDH) process using propane as raw material has gradually become one of the most competitive propylene production processes.

[0003] Existing propane dehydrogenation catalysts mainly include supported platinum-tin-based catalysts and chromium-based catalysts. For example, CN116059999A discloses a propane dehydrogenation catalyst and its preparation method and application, wherein the catalyst contains gallium, a first auxiliary agent, a second auxiliary agent and a composite oxide-based carrier containing silicon dioxide; the first auxiliary agent contains a noble metal of Group VIII, and the second auxiliary agent contains an alkali metal and / or an alkaline earth metal; based on the dry weight of the catalyst, the content of gallium in the catalyst is 0.01-10% by weight, the content of the first auxiliary agent is 0.001-0.045% by weight, and the content of the second auxiliary agent is 0.01-5% by weight; the ratio of the molar content of the second auxiliary agent in the catalyst to the molar content of the composite oxide-based carrier containing silicon dioxide is 1:(5-30).

[0004] However, the propane conversion rate, propylene selectivity and propylene yield of existing catalysts still need to be further improved. Summary of the invention

[0005] The object of the present invention is to provide a propane dehydrogenation catalyst and a preparation method thereof and a method for producing propylene, so as to further improve the propane conversion rate and propylene selectivity.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a propane dehydrogenation catalyst, which contains a carrier, an active component, a first auxiliary agent, a second auxiliary agent and a third auxiliary agent; the carrier is a composite oxide containing silicon dioxide, the active component contains gallium, the first auxiliary agent contains a noble metal element of Group VIII, the second auxiliary agent contains an alkali metal element and / or an alkaline earth metal element, and the third auxiliary agent contains a lanthanide metal element; in the composite oxide containing silicon dioxide, the total acid molar content is 30-160 μmol / g, and the medium-strong acid molar content is 20-110 μmol / g.

[0007] Optionally, based on the dry weight of the catalyst, the content of gallium in the catalyst is 0.1-10% by weight, the content of the first auxiliary agent is 0.001-0.050% by weight, the content of the second auxiliary agent is 0.1-5% by weight, and the content of the third auxiliary agent is 0.1-5% by weight; preferably, the content of gallium in the catalyst is 1-7% by weight, the content of the first auxiliary agent is 0.003-0.035% by weight, the content of the second auxiliary agent is 0.5-4% by weight, and the content of the third auxiliary agent is 0.5-4% by weight.

[0008] Optionally, the silicon dioxide-containing composite oxide carrier is a silicon-aluminum composite oxide, a zirconium-aluminum composite oxide, or a silicon-aluminum-zirconium composite oxide.

[0009] Optionally, based on the dry weight of the silicon-aluminum composite oxide, the SiO 2 The content of Al is 1-50% by weight, preferably 5-30% by weight. 2 O 3 The content is 50-99% by weight, preferably 70-95% by weight.

[0010] Optionally, based on the dry weight of the zirconium-aluminum composite oxide, the ZrO 2 The content of Al is 1-50% by weight, preferably 5-30% by weight. 2 O 3 The content is 50-99% by weight, preferably 70-95% by weight.

[0011] Optionally, based on the dry weight of the silicon-aluminum-zirconium composite oxide, the SiO 2 The content of Al is 0.5-30% by weight, preferably 1-20% by weight. 2 O 3 The content of ZrO is 50-90% by weight, preferably 60-80% by weight. 2 The content is 0.5-40% by weight, preferably 10-30% by weight.

[0012] Optionally, the specific surface area of ​​the composite oxide carrier containing silicon dioxide is 80-350m 2 / g, pore volume is 0.4-0.8cm 3 / g, bulk density is 0.2-0.8g / mL, total acid mole number is 50-150μmol / g, and medium-strong acid mole number is 30-100μmol / g.

[0013] Optionally, the Group VIII noble metal is selected from one or more of platinum, iridium and palladium, preferably platinum; the alkali metal is selected from one or more of lithium, sodium and potassium, the alkaline earth metal is selected from one or more of magnesium, barium and calcium; the lanthanide metal is selected from one or more of lanthanum, cerium and europium.

[0014] The second aspect of the present invention provides a method for preparing the catalyst provided in the first aspect of the present invention, the method comprising: mixing a gallium source, a precursor of a first auxiliary agent, a precursor of a second auxiliary agent, a precursor of a third auxiliary agent and a solvent to obtain an impregnation solution, and contacting the impregnation solution with a composite oxide support containing silica for impregnation, taking out the impregnated solid and optionally drying and calcining it.

[0015] Optionally, the impregnation conditions include: temperature of 20-80°C, time of 1-8 hours, and solid-liquid ratio of 1-4 g / mL; the calcination conditions include: temperature of 500-1000°C, time of 1-8 hours; preferably, temperature of 700-850°C, time of 2-8 hours; the drying conditions include: temperature of 30-200°C, time of 1-8 hours, and pressure of 0.01-0.1 MPa; preferably, temperature of 90-150°C, time of 2-6 hours, and pressure of 0.04-0.09 MPa.

[0016] Optionally, the gallium source is a soluble gallium-containing compound, preferably one or more of gallium nitrate, gallium chloride, and gallium sulfate; the precursor of the first auxiliary agent is a soluble platinum-containing compound, preferably one or more of chloroplatinic acid, ammonium chloroplatinate, and platinum chloride; the precursor of the second auxiliary agent is a soluble potassium- or calcium-containing compound, preferably one or more of potassium nitrate, potassium hydroxide, potassium chloride, potassium carbonate, calcium chloride, and calcium nitrate; the precursor of the third auxiliary agent is a soluble lanthanide metal-containing compound, preferably one or more of lanthanum nitrate, cerium nitrate, lanthanum chloride, cerium chloride, and europium nitrate; and the solvent is water.

[0017] The third aspect of the present invention provides a method for producing propylene by dehydrogenating propane, the method comprising: contacting propane with the catalyst provided by the first aspect of the present invention to carry out a dehydrogenation reaction.

[0018] Optionally, the dehydrogenation reaction is carried out in a fixed bed, moving bed or fluidized bed reactor, and the mass space velocity of the propane is 0.1-15h -1 , the temperature of the dehydrogenation reaction is 500-650℃.

[0019] Through the above technical scheme, the propane dehydrogenation catalyst of the present invention can maintain a high dehydrogenation catalytic activity while containing a low content of Group VIII noble metals. When used for a propane dehydrogenation reaction under non-hydrogen conditions, it has a high raw material conversion rate, as well as selectivity and yield for the target product, and has excellent stability and anti-sintering ability.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 is an electron microscope image of the catalyst of Example 1 of the present invention;

[0023] Figure 2 It is an electron microscope image of the catalyst of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0025] The first aspect of the present invention provides a propane dehydrogenation catalyst, which contains a carrier, an active component, a first auxiliary agent, a second auxiliary agent and a third auxiliary agent; the carrier is a composite oxide containing silicon dioxide, the active component contains gallium, the first auxiliary agent contains a noble metal element of Group VIII, the second auxiliary agent contains an alkali metal element and / or an alkaline earth metal element, and the third auxiliary agent contains a lanthanide metal element; in the composite oxide containing silicon dioxide, the total acid molar content is 30-160 μmol / g, and the medium-strong acid molar content is 20-110 μmol / g.

[0026] The present invention can reduce the occurrence of carbon deposition of the catalyst during the reaction process and improve the anti-sintering ability of the catalyst by adding the third auxiliary agent lanthanide metal element. At the same time, the noble metal of Group VIII is kept atomically dispersed on the composite oxide carrier containing silicon dioxide with a suitable acid content, and it is not easy to change from the atomically dispersed state to the agglomerated state under the conditions of the dehydrogenation reaction, so that good catalytic activity can be maintained and excellent dehydrogenation effect is achieved.

[0027] In the present invention, the content of the third auxiliary agent is calculated based on the amount of the lanthanide metal element.

[0028] According to the present invention, optionally, the content of gallium in the catalyst is 0.1-10% by weight, the content of the first auxiliary agent is 0.001-0.050% by weight, the content of the second auxiliary agent is 0.1-5% by weight, and the content of the third auxiliary agent is 0.1-5% by weight; preferably, the content of gallium in the catalyst is 1-7% by weight, the content of the first auxiliary agent is 0.003-0.035% by weight, the content of the second auxiliary agent is 0.5-4% by weight, and the content of the third auxiliary agent is 0.5-4% by weight. In the present invention, the content of the first auxiliary agent is calculated based on the amount of noble metal elements of Group VIII, and the content of the second auxiliary agent is calculated based on the total amount of alkali metal elements and alkaline earth metal elements.

[0029] According to the present invention, optionally, the ratio of the molar content of gallium in the catalyst to the molar content of silicon dioxide in the composite oxide support is 1:(0.1-30); preferably, the ratio of the molar content of gallium in the catalyst to the molar content of silicon dioxide in the composite oxide support is 1:(1-10), and more preferably 1:(3-7). The propane dehydrogenation catalyst of the present invention preferably has a molar content of gallium to the molar content of silicon dioxide in the composite oxide support of 1:(1-10), which enables the catalyst to maintain a high dehydrogenation catalytic activity while containing a low content of Group VIII noble metals, and has a high raw material conversion rate, as well as selectivity and yield for the target product when used in the propane dehydrogenation reaction. Further, in the case where the molar content of gallium to the molar content of silicon dioxide in the composite oxide support is more preferably 1:(3-7), the dehydrogenation catalyst has better catalytic activity for propane dehydrogenation and selectivity for the target product.

[0030] According to the present invention, optionally, the composite oxide carrier containing silica does not contain molecular sieves, and the composite oxide carrier containing silica may be a silicon-aluminum composite oxide, a zirconium-aluminum composite oxide, or a silicon-aluminum-zirconium composite oxide.

[0031] The composite oxide support containing silicon dioxide can be obtained by calcining an oxide mixture at a temperature of 500-1000° C. for 1-8 hours; preferably, the temperature is 700-850° C. for 2-6 hours. The oxide mixture may contain a binder, silicon oxide, and aluminum oxide and / or zirconium oxide. The binder may be at least one of aluminum sol, silica sol, and SB powder. The content of the binder in the oxide mixture may be 10-50% by weight. The content of silicon oxide, aluminum oxide, and / or zirconium oxide in the oxide mixture may be determined according to the content required in the composite oxide support containing silicon dioxide.

[0032] Optionally, based on the dry weight of the silicon-aluminum composite oxide, the SiO 2 The content of Al is 1-50% by weight, preferably 5-30% by weight. 2 O 3 The content is 50-99% by weight, preferably 70-95% by weight.

[0033] Optionally, based on the dry weight of the silicon-zirconium composite oxide, the zirconium-aluminum composite oxide contains ZrO 2 The content of Al is 1-50% by weight, preferably 5-30% by weight. 2 O 3 The content is 1-50% by weight, preferably 5-30% by weight.

[0034] Optionally, based on the dry weight of the silicon-aluminum-zirconium composite oxide, the SiO 2 The content of Al is 0.5-30% by weight, preferably 1-20% by weight; 2 O 3 The content of ZrO is 50-90% by weight, preferably 60-80% by weight. 2 The content of is 0.5-40% by weight, preferably 10-30% by weight. The specific surface area of ​​the composite oxide carrier containing silicon dioxide is 80-350m 2 / g, pore volume is 0.4-0.8cm 3 / g, the bulk density is 0.2-0.8 g / mL, the total acid mole number is 50-150 μmol / g, and the medium-strong acid mole number is 30-100 μmol / g. The specific surface area and pore volume of the composite oxide carrier containing silicon dioxide in the present invention can be obtained by BET detection, and the total acid mole number and the medium-strong acid mole number can be detected by Py-IR (pyridine infrared test), and the BET and Py-IR detection methods are well known to those skilled in the art, such as the determination of the total acid mole number and the medium-strong acid mole number using the Nicolet 6700 Fourier transform infrared spectrometer produced by Thermo Scientific, USA, and the carrier is subjected to acid analysis under the action of pyridine probe. The temperature of pyridine molecule desorption is proportional to the acid strength, generally the acid amount under 200 ℃ of conditions is used as the total acid amount, and the acid amount under 350 ℃ of conditions is used as the medium-strong acid amount, and the peak area is integrated and the acid amount is calculated. In the above embodiment, the silicon-aluminum-zirconium composite oxide has excellent specific surface area, pore size distribution, acidity and activity. The active components and additives of the present invention have high catalytic performance on the silicon-aluminum-zirconium composite oxide carrier, which can improve the selectivity and yield of the target product.

[0035] According to the present invention, optionally, the Group VIII noble metal is selected from one or more of platinum, iridium and palladium, preferably platinum; the alkali metal is selected from one or more of lithium, sodium and potassium, preferably potassium; the alkaline earth metal is selected from one or more of magnesium, barium and calcium, preferably calcium; the lanthanide metal is selected from one or more of lanthanum, cerium and europium.

[0036] The second aspect of the present invention provides a method for preparing the catalyst provided in the first aspect of the present invention, the method comprising: mixing a gallium source, a precursor of a first auxiliary agent, a precursor of a second auxiliary agent, a precursor of a third auxiliary agent and a solvent to obtain an impregnation solution, and contacting the impregnation solution with a composite oxide support containing silica for impregnation, taking out the impregnated solid and optionally drying and calcining it.

[0037] In the present invention, the feeding amount of each raw material can be adjusted so that, based on the dry weight of the catalyst, the content of gallium in the catalyst is 0.01-10% by weight, the content of the first auxiliary agent is 0.01-0.1% by weight, the content of the second auxiliary agent is 0.01-5% by weight, and the content of the third auxiliary agent is 0.01-5% by weight; the ratio of the molar content of the gallium element in the catalyst to the molar content of silicon dioxide in the composite oxide carrier is 1:(0.1-30).

[0038] According to the present invention, optionally, the conditions of the impregnation include: temperature of 20-80°C, time of 1-8 hours, solid-liquid ratio of 1-4 g / mL; preferably, temperature of 25-55°C, solid-liquid ratio of 1.2-2.5 g / mL. Preferably, the method further includes: aging the solid obtained after the impregnation and then calcining, and the aging time is 1-10 hours.

[0039] According to the present invention, optionally, the calcination conditions include: a temperature of 500-1000°C and a time of 1-8 hours; preferably, a temperature of 700-850°C and a time of 2-8 hours. Calcination is an operation well known to those skilled in the art, and the calcination can be carried out in equipment conventionally used by those skilled in the art, such as a muffle furnace or a tubular furnace. The present invention does not specifically limit the calcination atmosphere, such as an air atmosphere or an inert atmosphere, and the inert atmosphere can contain nitrogen, argon and other inert gases.

[0040] According to the present invention, optionally, the drying conditions include: temperature of 30-200°C, time of 1-8 hours, and pressure of 0.01-0.1MPa; preferably, temperature of 90-150°C, time of 2-6 hours, and pressure of 0.04-0.09MPa. The present invention does not specifically limit the drying method, for example, it can be dried at a constant temperature or vacuum dried, preferably vacuum dried.

[0041] According to the present invention, optionally, the gallium source is a soluble gallium-containing compound, preferably one or more of gallium nitrate, gallium chloride, and gallium sulfate; the precursor of the first auxiliary agent is a soluble platinum-containing compound, preferably one or more of chloroplatinic acid, ammonium chloroplatinate, and platinum chloride; the precursor of the second auxiliary agent is a soluble potassium- or calcium-containing compound, preferably one or more of potassium nitrate, potassium hydroxide, potassium chloride, potassium carbonate, calcium chloride, and calcium nitrate; the precursor of the third auxiliary agent is a soluble lanthanide metal-containing compound, preferably one or more of lanthanum nitrate, cerium nitrate, lanthanum chloride, cerium chloride, and europium nitrate; and the solvent may be water.

[0042] The third aspect of the present invention provides a method for producing propylene by dehydrogenating propane, the method comprising: contacting propane with the catalyst provided by the first aspect of the present invention to carry out a dehydrogenation reaction.

[0043] According to the present invention, optionally, the dehydrogenation reaction is carried out in a fixed bed, a moving bed or a fluidized bed reactor, and the mass space velocity of the propane is 0.1-15h -1 , the temperature of the dehydrogenation reaction is 500-650℃.

[0044] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0045] Example 1

[0046] Gallium nitrate, chloroplatinic acid (H 2 PtCl 6 ), potassium nitrate, cerium chloride and deionized water are mixed to obtain an impregnation solution; at 20°C and a liquid-to-solid ratio of 1.4 g / mL, the carrier is impregnated with the impregnated solution, the impregnated solid is rotary evaporated to dryness at 75°C and a vacuum degree of -0.08 MPa, then dried at 120°C for 6 hours, and finally calcined in a muffle furnace at 750°C for 4 hours to obtain catalyst A.

[0047] Based on the dry weight of the catalyst, the gallium content in the catalyst is 4.5 wt%, the platinum content is 0.03 wt%, the potassium content is 1.75 wt%, and the cerium content is 1.0 wt%. The carrier is a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 10% by weight 2 O 3 The content of ZrO is 80% by weight 2 The content is 10% by weight and the specific surface area is 242m 2 / g, pore volume is 0.54cm 3 / g, the bulk density is 0.75g / mL, the total acid molar amount is 128μmol / g, and the medium-strong acid molar amount is 82μmol / g.

[0048] Example 2

[0049] Catalyst B was prepared by the same method as in Example 1, except that gallium nitrate and chloroplatinic acid (H 2 PtCl 6 ), calcium nitrate, cerium chloride and deionized water are mixed to obtain an impregnation solution. Based on the dry weight of the catalyst, the gallium content in the catalyst is 3.5 weight%, the platinum content is 0.01 weight%, the calcium content is 1.5 weight%, and the cerium content is 1.5 weight%; the carrier is a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 5% by weight 2 O 3 The content of ZrO is 70% by weight 2 The content is 25% by weight and the specific surface area is 269m 2 / g, pore volume is 0.75cm 3 / g, the bulk density is 0.45g / mL, the total acid molar amount is 134μmol / g, and the medium-strong acid molar amount is 96μmol / g.

[0050] Example 3

[0051] Catalyst C was prepared by the same method as in Example 1, except that, based on the dry weight of the catalyst, the gallium content in the catalyst was 4.5 wt%, the platinum content was 0.005 wt%, the potassium content was 1.25 wt%, and the cerium content was 0.5 wt%; the carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 5% by weight 2 O 3 The content of ZrO is 65% by weight 2 The content is 30% by weight and the specific surface area is 287m 2 / g, pore volume is 0.73cm 3 / g, the bulk density is 0.34g / mL, the total acid molar amount is 143μmol / g, and the medium-strong acid molar amount is 92μmol / g.

[0052] Example 4

[0053] Catalyst D was prepared by the same method as in Example 1, except that gallium nitrate and chloroplatinic acid (H 2 PtCl 6 ), potassium nitrate, lanthanum nitrate and deionized water are mixed to obtain an impregnation solution; based on the dry weight of the catalyst, the gallium content in the catalyst is 3.5 weight%, the platinum content is 0.01 weight%, the potassium content is 2.0 weight%, and the lanthanum content is 2.0 weight%; the carrier is a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 10% by weight 2 O3 The content of ZrO is 75% by weight 2 The content is 15% by weight and the specific surface area is 261m 2 / g, pore volume is 0.69cm 3 / g, the bulk density is 0.59g / mL, the total acid molar amount is 137μmol / g, and the medium-strong acid molar amount is 66μmol / g.

[0054] Example 5

[0055] Catalyst E was prepared by the same method as in Example 1, except that, based on the dry weight of the catalyst, the gallium content in the catalyst was 4.5 wt%, the platinum content was 0.03 wt%, the potassium content was 0.5 wt%, and the cerium content was 2.5 wt%; the carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 20% by weight 2 O 3 The content of ZrO is 60% by weight 2 The content is 20% by weight and the specific surface area is 308m 2 / g, pore volume is 0.80cm 3 / g, the bulk density is 0.32g / mL, the total acid molar number is 138μmol / g, and the medium-strong acid molar number is 75μmol / g.

[0056] Example 6

[0057] Catalyst F was prepared by the same method as in Example 1, except that, based on the dry weight of the catalyst, the gallium content in the catalyst was 3.5 wt%, the platinum content was 0.01 wt%, the potassium content was 1.5 wt%, and the cerium content was 0.8 wt%; the carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 10% by weight 2 O 3 The content of ZrO is 75% by weight 2 The content is 15% by weight and the specific surface area is 261m 2 / g, pore volume is 0.69cm 3 / g, the bulk density is 0.59g / mL, the total acid molar amount is 137μmol / g, and the medium-strong acid molar amount is 66μmol / g.

[0058] Example 7

[0059] Catalyst G was prepared by the same method as in Example 1, except that, based on the dry weight of the catalyst, the gallium content in the catalyst was 3.5 wt%, the platinum content was 0.01 wt%, the potassium content was 1.5 wt%, and the cerium content was 6 wt%; the carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO2 The content of Al is 10% by weight 2 O 3 The content of ZrO is 75% by weight 2 The content is 15% by weight and the specific surface area is 261m 2 / g, pore volume is 0.69cm 3 / g, the bulk density is 0.59g / mL, the total acid molar amount is 137μmol / g, and the medium-strong acid molar amount is 66μmol / g.

[0060] Example 8

[0061] Catalyst H was prepared by the same method as in Example 1, except that gallium nitrate and chloroplatinic acid (H 2 PtCl 6 ), magnesium nitrate, europium nitrate and deionized water are mixed to obtain an impregnation solution; based on the dry weight of the catalyst, the gallium content in the catalyst is 3.5 weight%, the platinum content is 0.01 weight%, the magnesium content is 2.0 weight%, and the europium content is 0.7 weight%; the carrier is a silicon-aluminum composite oxide, wherein SiO 2 The content of Al is 30% by weight 2 O 3 The content is 70% by weight and the specific surface area is 347m 2 / g, pore volume is 0.76cm 3 / g, the bulk density is 0.28g / mL, the total acid molar amount is 135μmol / g, and the medium-strong acid molar amount is 83μmol / g.

[0062] Example 9

[0063] Catalyst I was prepared by the same method as in Example 1, except that gallium nitrate and chloroplatinic acid (H 2 PtCl 6 ), sodium nitrate, lanthanum nitrate and deionized water are mixed to obtain an impregnation solution; based on the dry weight of the catalyst, the gallium content in the catalyst is 4.5 weight%, the platinum content is 0.03 weight%, the sodium content is 1.5 weight%, and the lanthanum content is 1.2 weight%; the carrier is a zirconium aluminum composite oxide, wherein ZrO 2 The content of Al is 15% by weight 2 O 3 The content is 85% by weight and the specific surface area is 279m 2 / g, pore volume is 0.70cm 3 / g, the bulk density is 0.28g / mL, the total acid molar amount is 116μmol / g, and the medium-strong acid molar amount is 67μmol / g.

[0064] Comparative Example 1

[0065] Catalyst DA was prepared by the same method as in Example 1, except that the third auxiliary agent, cerium chloride, was not added. Based on the dry weight of the catalyst, the gallium content in the catalyst was 4.5 wt%, the platinum content was 0.03 wt%, and the potassium content was 1.75 wt%. The carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 10% by weight 2 O 3 The content of ZrO is 80% by weight 2 The content is 10% by weight and the specific surface area is 242m 2 / g, pore volume is 0.54cm 3 / g, the bulk density is 0.75g / mL, the total acid molar amount is 128μmol / g, and the medium-strong acid molar amount is 82μmol / g.

[0066] Comparative Example 2

[0067] Catalyst DB was prepared by the same method as in Example 1, except that potassium nitrate was not added as the second auxiliary agent. Based on the dry weight of the catalyst, the gallium content in the catalyst was 3.5 wt%, the platinum content was 0.03 wt%, and the cerium content was 0.5 wt%. The carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 5% by weight 2 O 3 The content of ZrO is 65% by weight 2 The content is 30% by weight and the specific surface area is 287m 2 / g, pore volume is 0.73cm 3 / g, the bulk density is 0.34g / mL, the total acid molar amount is 143μmol / g, and the medium-strong acid molar amount is 92μmol / g.

[0068] Comparative Example 3

[0069] Catalyst DC was prepared by the same method as in Example 1, except that, based on the dry weight of the catalyst, the gallium content in the catalyst was 4.5 wt%, the platinum content was 0.03 wt%, the potassium content was 1.75 wt%, and the cerium content was 1.0 wt%; the carrier was a silicon-aluminum-zirconium composite oxide, wherein SiO 2 The content of Al is 40% by weight 2 O 3 The content of ZrO is 10% by weight 2 The content is 50% by weight and the specific surface area is 504m 2 / g, pore volume is 0.86cm 3 / g, the bulk density is 0.14g / mL, the total acid molar amount is 178μmol / g, and the medium-strong acid molar amount is 135μmol / g.

[0070] Test Case

[0071] In the microreactor, 1.5 g of catalyst was loaded, propane was used as the raw material, and the mass space velocity of propane feed was 3.5 h-1 at 580 °C and 0.03 MPa. -1 The reaction was carried out under the conditions of 100 °C, and propane was introduced for 5 min before sampling. The reaction was continued for 10 h. The propane conversion and propylene selectivity were calculated. The deactivation rate constant (kd, h -1 ) to evaluate catalyst stability, deactivation rate constant (kd, h -1 ) is calculated by the following equation. in and X end are the propane conversion at the beginning and end of the reaction, respectively, and t is the reaction time. The conversion, propylene selectivity and deactivation rate constant of propane dehydrogenation reaction are shown in Table 1.

[0072]

[0073] Table 1

[0074]

[0075]

[0076] From Table 1 and Figure 1 and Figure 2 It can be seen that the present invention can keep the platinum element in an atomic-level dispersion state on the catalyst for a long time by adding the third auxiliary agent lanthanide metal element. When the propane dehydrogenation reaction is carried out under non-hydrogen conditions, the platinum is not easy to agglomerate and still has good catalytic activity, so that the propane dehydrogenation catalyst has a higher propane conversion rate, propylene selectivity and yield, and has better stability and anti-sintering ability. In Comparative Example 1, no third auxiliary agent is added. During the reaction, platinum is easy to agglomerate, which reduces the catalytic activity of the catalyst, and reduces the propane conversion rate, propylene selectivity and yield. In Comparative Example 2, no second auxiliary agent is added. The catalyst carrier is highly acidic, and side reactions are prone to occur during the reaction, which reduces the active sites of the catalyst and is prone to carbon deposition and deactivation. In Comparative Example 3, the silicon oxide and zirconium oxide content of the carrier is too high, and the acidity is too strong, so that the catalyst has almost no catalytic activity. In the case of preferably adding a more suitable amount of the third auxiliary agent, platinum is more evenly dispersed on the carrier, and the catalytic performance is greatly improved.

[0077] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0079] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A propane dehydrogenation catalyst, characterized in that: The catalyst contains a carrier, an active component, a first auxiliary agent, a second auxiliary agent and a third auxiliary agent; the carrier is a composite oxide containing silicon dioxide, the active component contains gallium, the first auxiliary agent contains a noble metal element of Group VIII, the second auxiliary agent contains an alkali metal element and / or an alkaline earth metal element, and the third auxiliary agent contains a lanthanide metal element; in the composite oxide containing silicon dioxide, the total acid molar content is 30-160 μmol / g, and the medium-strong acid molar content is 20-110 μmol / g.

2. The catalyst according to claim 1, wherein Based on the dry weight of the catalyst, the content of gallium in the catalyst is 0.1-10% by weight, the content of the first auxiliary agent is 0.001-0.050% by weight, the content of the second auxiliary agent is 0.1-5% by weight, and the content of the third auxiliary agent is 0.1-5% by weight; Preferably, the content of gallium in the catalyst is 1-7% by weight, the content of the first auxiliary agent is 0.003-0.035% by weight, the content of the second auxiliary agent is 0.5-4% by weight, and the content of the third auxiliary agent is 0.5-4% by weight.

3. The catalyst according to claim 1, wherein The silicon dioxide-containing composite oxide carrier is a silicon-aluminum composite oxide, a zirconium-aluminum composite oxide, or a silicon-aluminum-zirconium composite oxide. Based on the dry weight of the silicon-aluminum composite oxide, the content of SiO2 in the silicon-aluminum composite oxide is 1-50% by weight, preferably 5-30% by weight, and the content of Al2O3 is 50-99% by weight, preferably 70-95% by weight; Based on the dry weight of the zirconium-aluminum composite oxide, the content of ZrO2 in the zirconium-aluminum composite oxide is 1-50% by weight, preferably 5-30% by weight, and the content of Al2O3 is 50-99% by weight, preferably 70-95% by weight; Based on the dry weight of the silicon-aluminum-zirconium composite oxide, the SiO2 content in the silicon-aluminum-zirconium composite oxide is 0.5-30 weight %, preferably 1-20 weight %, the Al2O3 content is 50-90 weight %, preferably 60-80 weight %, and the ZrO2 content is 0.5-40 weight %, preferably 10-30 weight %.

4. The catalyst according to claim 1 or 3, wherein The specific surface area of ​​the composite oxide carrier containing silicon dioxide is 80-350m 2 / g, pore volume is 0.4-0.8cm 3 / g, bulk density is 0.2-0.8g / mL, total acid mole number is 50-150μmol / g, and medium-strong acid mole number is 30-100μmol / g.

5. The catalyst according to claim 1, wherein The Group VIII noble metal is selected from one or more of platinum, iridium and palladium, preferably platinum; the alkali metal is selected from one or more of lithium, sodium and potassium, the alkaline earth metal is selected from one or more of magnesium, barium and calcium; the lanthanide metal is selected from one or more of lanthanum, cerium and europium.

6. A method for preparing the catalyst according to any one of claims 1 to 5, the method comprising: A gallium source, a precursor of a first auxiliary agent, a precursor of a second auxiliary agent, a precursor of a third auxiliary agent and a solvent are mixed to obtain an impregnation solution, and the impregnation solution is contacted with a composite oxide support containing silicon dioxide for impregnation, and the impregnated solid is taken out and optionally dried and calcined.

7. The method according to claim 6, wherein: The conditions of the impregnation include: a temperature of 20-80°C, a time of 1-8 hours, and a solid-liquid ratio of 1-4 g / mL; The calcination conditions include: a temperature of 500-1000°C and a time of 1-8 hours; preferably, a temperature of 700-850°C and a time of 2-8 hours; The drying conditions include: temperature of 30-200° C., time of 1-8 hours, and pressure of 0.01-0.1 MPa; preferably, temperature of 90-150° C., time of 2-6 hours, and pressure of 0.04-0.09 MPa.

8. The method according to claim 6, wherein: The gallium source is a soluble gallium-containing compound, preferably one or more of gallium nitrate, gallium chloride, and gallium sulfate; The precursor of the first auxiliary agent is a soluble platinum-containing compound, preferably one or more of chloroplatinic acid, ammonium chloroplatinate, and platinum chloride; The precursor of the second auxiliary agent is a soluble compound containing potassium or calcium, preferably one or more of potassium nitrate, potassium hydroxide, potassium chloride, potassium carbonate, calcium chloride, and calcium nitrate; The precursor of the third auxiliary agent is a soluble compound containing a lanthanide metal, preferably one or more of lanthanum nitrate, cerium nitrate, lanthanum chloride, cerium chloride and europium nitrate; The solvent is water.

9. A method for producing propylene by dehydrogenating propane, characterized in that: The method comprises: contacting propane with the catalyst described in any one of claims 1 to 5 to carry out a dehydrogenation reaction.

10. The method according to claim 9, wherein: The dehydrogenation reaction is carried out in a fixed bed, moving bed or fluidized bed reactor, and the mass space velocity of the propane is 0.1-15h -1 , the temperature of the dehydrogenation reaction is 500-650℃.

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