CN117339607A

CN117339607A - Catalyst for preparing acrylic acid by catalyzing propane and application thereof

Info

Publication number: CN117339607A
Application number: CN202210764910.1A
Authority: CN
Inventors: 刘肖飞; 杨红强; 黄鑫; 南洋; 魏珍妮; 张丽桦; 李燕
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2022-06-29
Filing date: 2022-06-29
Publication date: 2024-01-05

Abstract

The invention relates to a catalyst for preparing acrylic acid by catalyzing propane and application thereof, wherein the catalyst is represented by the following general formula: mo (Mo) _a V _b Te _c Nb _d Ni _e B _f O _x Wherein a, b, c, d, e, f each represents an atomic number of Mo, V, te, nb, ni, B, a: b: c: d: e: f is 9.5 to 10.1:2.2 to 2.5:2.0 to 2.3:1.8 to 2.0:0.1 to 1.0:0.05 to 0.85, x being determined by the oxidation state of each element; ni is introduced through nickel molybdate, and Mo is introduced through molybdate and the nickel molybdate. The invention introduces nickel into the catalyst by using nickel molybdate, and can adjust the content of metals with different valence states on the surface of the catalyst, so that the catalystHigh valence element Mo ⁶⁺ 、V ⁵⁺ And Ni ²⁺ The content is increased, the oxidation-reduction capability of the catalyst is enhanced, and the propane conversion activity is improved.

Description

Catalyst for preparing acrylic acid by catalyzing propane and application thereof

Technical Field

The invention belongs to the technical field of catalysts, and particularly relates to a catalyst for preparing acrylic acid by catalyzing propane and application thereof.

Background

Acrylic acid is an important organic chemical raw material and an oilfield chemical auxiliary agent, is pulled by strong demands in four fields of construction, textile, sanitation and materials, is developed at a high speed in the market of China acrylic acid ester, is the largest acrylic acid consumption country and production country worldwide in China, and gradually develops to large-scale, full-industry-chaining and high-end development. At present, propylene is used as a raw material in industry, and acrylic acid is synthesized mainly by adopting a two-step reaction, namely, the propylene firstly reacts with oxygen to generate acrolein, and then the acrolein is oxidized to generate acrylic acid. The propylene demand is rapidly increased while the global propylene productivity is slowly increased, and the gap is continuously increased.

The petrochemical raw material in the 21 st century will probably be turned to be mainly based on cheaper natural gas alkanes, so the transfer of the raw material route from alkene to alkane will be one of the important points of research and development of petrochemical technology in the new century. The low-carbon alkane exists widely worldwide, and can bring great economic benefit by converting the low-carbon alkane into chemical products with high added value. Similar difficulties are faced in chemical conversion of lower alkanes: the raw materials are stable, the price is low, but the conversion is difficult, and the target product is more active and is easy to be deeply oxidized. Therefore, it is difficult to obtain high conversion rate and selectivity at the same time for the target product of chemical conversion of low-carbon alkane, and there is a high possibility that the two will have a "teeterboard" relationship. To date, only a few reactions have been carried out to produce maleic anhydride, for example, ethylene by steam cracking of ethane, propylene by dehydrogenation of propane, and selective oxidation of butane. Possible commercial alkane activation technologies in the 21 st century include ethane to acetic acid, isobutane to methacrylic acid, ethane to ethylene by catalytic dehydrogenation, propane to acrylic acid, and the like.

Propane is one of the important components of natural gas, liquefied petroleum gas, and coalbed methane. China is a country with rich propane resources, for example, about 6% of propane in oil field gas, about 60% of liquefied petroleum gas, up to 15% of wet natural gas, and a certain amount of propane is contained in refinery gas. A recent study in the world energy institute (WRI) shows that Chinese shale gas has a storage capacity of up to more than 30 trillion cubic meters, and is first in the world, almost twice as much as the United states. With the accelerated exploitation of unconventional oil gas such as shale gas, the potential supply amount of propane is more. They are generally used as fuel or burned off by emptying, and the resource waste is large. How to convert the low-carbon alkane into chemical products with high added value, reduces the dependence on petroleum, has huge economic benefit and potential social benefit of delaying the exhaustion of petroleum. Therefore, the research on the aspects of preparing propylene by oxidative dehydrogenation, preparing acrolein, acrylic acid, isopropanol and acetone by selective oxidation, dehydrogenating and aromatizing, preparing acrylonitrile by ammoxidation and the like is significant.

The selective oxidation of propane to produce acrylic acid is a complex integrated system process, and catalyst development is the core technology of the reaction process. In addition, reactor type and design, reaction condition control, product separation, etc. are all major subjects of research. To date, there are 3 catalyst systems in the production of acrylic acid by the selective oxidation of propane: (1) Catalyst for preparing maleic anhydride by selective oxidation of industrial n-butane: VPO-based catalysts; (2) alkane oxidative dehydrogenation catalyst: heteropolyacid and its salt catalyst HxCs3-xPMO12O40 (x=0-3) (HPC); (3) propane ammoxidation and alkane oxidative dehydrogenation catalysts: composite metal oxide (MMO) catalysts. The majority of the research on catalysts for the selective oxidation of propane to acrylic acid is derived from these 3 catalyst systems.

VPO catalysts were a very successful class of catalysts developed in the 70 s of the 20 th century to oxidize n-butane to maleic anhydride. In 1986, VPO catalyst was first used for the selective oxidation of propane, with acrylic acid and carbon oxides as the products, but propyleneThe yield of alkenoic acid is quite low. Cheng Hua et al added 0.01% Ce to the VPO catalyst gave an acrylic acid yield of 18.8% with selectivity as high as 68%, which is a relatively high acrylic acid yield. The microwave heating process has been reported to produce a VPO catalyst containing Ce and La. The results showed that the catalyst composition was n (P): n (V): n (La): n (Ce) =1.1: 1.0:0.04: the highest propane conversion and acrylic acid selectivity at 0.04 were achieved to 50.3% and 85.5%, respectively. CeP was considered by X-ray diffraction and laser Raman spectroscopy ₅ O ₁₄ Sum (VO) ₂ P ₂ O ₇ The synergistic effect which may be produced between the two phases maintains the catalyst stability and improves the propane conversion and acrylic acid selectivity. Although this is the best acrylic acid selectivity and yield of current VPO catalysts, the reaction temperature of this catalyst is higher, at 450 ℃. From the existing research results, the preparation of acrylic acid by using the VPO catalyst has no breakthrough progress, and the industrial production requirement is far from being met.

HPC has self advantages as a catalyst for preparing acrylic acid by selective oxidation of propane. The structure is determined, and the composition is simple. As a catalyst, HPC is both acidic and redox, and is a bifunctional catalyst. However, the catalyst has poor stability and quick activity reduction. Because Keggin type anions of the heteropoly acid catalyst are subject to structural decomposition in an air atmosphere at 400 ℃. Therefore, for HPC of propane selective oxidation, it is critical to improve its thermal stability. H prepared by Hong et al _x Cu _0.6 Cr _0.6 PMo ₁₀ V ₂ As _0.6 O ₄₀ The catalyst obtains the highest yield (14.8%) of acrylic acid on an HPCs system at present, and the breakthrough of the HPC applied to the preparation of acrylic acid by the selective oxidation of propane is not realized.

The composite metal oxide catalyst for the selective oxidation of propane is mainly a transition metal oxide catalyst. Compared with VPO and HPC catalysts, MMO catalysts have a complex structure and performance relationship. The heat stability is better because the material is roasted at high temperature in the preparation process. The currently industrially applied catalysts for the oxidation of propylene to acrolein and acrylic acid are also included in this system. In recent years, the composite metal oxide has been found to have a good catalytic effect on the reaction of producing acrylic acid by selective oxidation of propane, and is therefore regarded as a hot spot for research. At present, most of the composite metal oxides used for preparing acrylic acid by propane oxidation are transition metal oxides, and mainly comprise Mo-V-Sb, mo-V-Te-Nb, mo-V-Sb-Nb and other composite metal oxides. The most studied is Mo-V-Te-Nb and Mo-V-Sb-Nb catalysts. Although the preparation process of the catalyst is complex, the composition of byproducts is various, and the stability and reproducibility of the catalyst are still to be improved, the catalyst has higher catalytic activity than VPO and HPA catalysts, higher reaction activity and selectivity of target products, higher thermal stability, less loss of active components, less carbon deposition phenomenon in low-temperature and high-temperature reactions, and the like, so that the catalyst is more suitable for being used as a catalyst for the reaction for preparing acrylic acid by the selective oxidation of propane. Among the several main catalyst systems used for preparing acrylic acid by the selective oxidation of propane, the Mo-V-Te-Nb catalyst system is the best catalyst system for preparing acrylic acid by the selective oxidation of propane at present because of higher reactivity and target product selectivity. Many researchers have conducted intensive studies on the catalyst preparation method and conditions, catalyst bulk and surface crystal structure, catalytic kinetics, and the like. At present, no report of industrial application is seen at home and abroad for preparing acrylic acid by oxidizing propane, and the report still remains in a laboratory research stage.

The first time in 1997 that the Mo-V-Te-Nb-O system catalyst has extremely high activity and selectivity for preparing acrylonitrile by selective ammoxidation of propane, the highest acrylonitrile yield reaches nearly 50%. MoV first developed by Mitsubishi corporation of Japan _0.3 Te _0.23 Nb _0.l2 O _x The catalyst is the composite metal oxide catalyst with the best catalytic performance reported at present, and the yield of the obtained acrylic acid is 48%. But MoV prepared by different researchers _0.3 Te _0.23 Nb _0.l2 O _x The acrylic acid yields of the catalysts vary considerably. This is probably due to the fact that the catalyst has many constituent elements and the preparation process is complicated. Therefore, strict control of the catalyst preparation conditions is critical to obtaining the desired acrylic acid.

Patent number CN1596244a reports a method for producing acrylic acid from propane in the absence of molecular oxygen, and a gas mixture containing propane, steam and inert gas in the absence of molecular oxygen is passed through the catalyst reported in the patent, the use of the method reduces the problem of high content of propionic acid as a byproduct in the previous process of producing acrylic acid from propane, significantly reduces the ratio of propionic acid to acrylic acid at the outlet of the reactor, and simultaneously reduces the content of acetone as a byproduct, but the yield of acrylic acid is only 10.5%.

Patent No. CN1326378A reports a catalytic system for low temperature partial oxidation of propane with a molecular oxygen containing gas Mo-V-Ga-Pd-Nb-X (where x=la, te, etc.). The catalyst produces acrylic acid at low temperature through gas phase partial oxidation of propane, the temperature is 200-300 ℃, the pressure is normal pressure, and the reaction space velocity is 200-3000 LKg ^-1 h ^-1 Under the condition of (1) the conversion rate of propane is 10% -25% and the selectivity of acrylic acid is 20% -45%.

Patent No. CN102179261A reports that acrylic acid is prepared by catalyzing propane oxidation by Mo, V, te, nb as an active component, and the patent provides a method for preparing an acrylic acid composite metal oxide catalyst by propane selective oxidation with a periodic and regular ordered structure by a template synthesis method, which solves the problems of larger particle size, uneven structure and the like in the prior catalyst preparation process, the conversion rate of propane is 68.3 percent at most, the yield of acrylic acid is about 45 percent, but the template synthesis method leads to higher preparation cost.

Patent CN114534750A discloses a preparation method of a catalyst for preparing acrylic acid by selectively oxidizing propane, which comprises the steps of fixing the mole ratio of active components of Mo-V-Te-Nb, adding an auxiliary agent NiSb into the active components of Mo-V-Te-Nb ₂ O ₆ The method of (2) effectively improves the activity, the selectivity and the stability of the catalyst, and NiSb ₂ O ₆ The introduction of structure helps to reduce the total acid content of the catalyst surface. NiSb involved in the method ₂ O ₆ The catalyst is obtained by roasting at a high temperature of more than 800 ℃, mixing the catalyst with several active components of Mo-V-Te-Nb, granulating, forming, drying and roasting. Therefore, the catalyst can be prepared by twice roasting in the preparation process, and the preparation process is longResulting in higher manufacturing costs.

Disclosure of Invention

The invention aims to provide a catalyst for preparing acrylic acid by catalyzing propane, which solves the problems of long catalyst preparation flow and serious deep oxidation of products in the prior art and further develops the application value of a Mo-V system composite metal oxide catalyst in industry.

The invention also aims to provide the application of the catalyst for preparing the acrylic acid by catalyzing propane in the slurry bed reactor.

In order to achieve the above object, the present invention provides a catalyst for producing acrylic acid by catalyzing propane, which is represented by the following general formula:

Mo _a V _b Te _c Nb _d Ni _e B _f O _x

wherein a, b, c, d, e, f each represents an atomic number of Mo, V, te, nb, ni, B, a: b: c: d: e: f is 9.5 to 10.1:2.2 to 2.5:2.0 to 2.3:1.8 to 2.0:0.1 to 1.0:0.05 to 0.85, x being determined by the oxidation state of each element; ni is introduced through nickel molybdate, mo is introduced through molybdate and the nickel molybdate, and the nickel molybdate is prepared by coprecipitation of molybdate and nickel salt in the presence of organic acid.

The invention relates to a catalyst for preparing acrylic acid by catalyzing propane, which is prepared by the following steps:

1) Dissolving molybdate, vanadate, tellurium compound, niobium salt and boride, uniformly mixing, coprecipitating to form slurry, drying and crushing to prepare Mo-V-Te-Nb-B component; 2) Uniformly mixing organic acid, nickel salt, molybdate and deionized water, and drying, roasting and crushing to obtain a nickel molybdate component; 3) Mixing the Mo-V-Te-Nb-B component and the nickel molybdate component, dry-mixing the materials, adding the binder and deionized water, stirring to form slurry, and forming, drying and roasting to obtain the catalyst.

The roasting temperature in the step 3) is more than or equal to 600 ℃.

In the catalyst for preparing acrylic acid by catalyzing propane, in the step 2), organic acid, nickel salt, molybdate and deionized water are mixed within the pH range of 2-5.

In the step 1), the molybdate is one of ammonium heptamolybdate and ammonium tetramolybdate, the vanadate is one of ammonium metavanadate and vanadyl oxalate, the tellurium compound is one of telluric acid and tellurium dioxide, the niobium salt is one of niobium oxalate, niobium acetate and ammonium niobium oxalate, and the boride is boric anhydride or boric acid; the organic acid in the step 2) is one of oxalic acid and citric acid, and the nickel salt is one of nickel acetate, nickel nitrate and basic nickel carbonate.

The binder in the step 3) is one or more of silica sol, aluminum sol and silica-alumina sol, and preferably silica sol.

The catalyst for preparing acrylic acid by propane catalysis disclosed by the invention is characterized in that the addition amount of a binder in the step 3) is 10-20wt% of the total amount of a Mo-V-Te-Nb-B component and a nickel molybdate component, and the addition amount of deionized water is 30-40wt% of the total amount of the Mo-V-Te-Nb-B component and the nickel molybdate component.

In order to achieve the above object, the present invention also provides a use of the above catalyst in a slurry bed reactor in which a mixture of deionized water, propane, oxygen and nitrogen is bubbled through a slurry layer in which catalyst fines are suspended in a slurry bed, the slurry temperature in the slurry bed reactor being from 430 ℃ to 500 ℃.

The catalyst is applied to a slurry bed reactor, and the total mass space velocity is 1000 ml/(g.h) to 3000 ml/(g.h), the volume ratio of oxygen to propane is=1 to 5, the volume ratio of water to propane is=1 to 5, and the balance is nitrogen.

The application of the catalyst in the slurry bed reactor is that propane accounts for 5-15 vol% of the total gas amount.

The invention has the beneficial effects that:

the catalyst of the invention uses self-made nickel molybdate as an auxiliary active component, and nickel is introduced into the catalyst through the nickel molybdateThe nickel molybdate is prepared by coprecipitation of molybdate and nickel salt in the presence of organic acid, carboxyl groups in the organic acid can disperse lattice clusters, so that nickel molybdate oxide is 'fine crystallized', the content of metals with different valence states on the surface of the catalyst can be regulated, and high-valence state element Mo in the catalyst can be realized ⁶⁺ 、V ⁵⁺ And Ni ²⁺ The content is increased, the oxidation-reduction capability of the catalyst is enhanced, and thus the propane conversion activity is improved. In addition, the nickel molybdate can be mixed with the Mo-V-Te-Nb-B component to prepare the catalyst without high-temperature roasting and low-temperature drying, so that the preparation process is simplified.

In the traditional process, a tubular fixed bed reactor is adopted, the local temperatures of different positions in a catalyst bed are difficult to control, the phenomenon of 'flying temperature' is easy to occur, and the stable operation is not good. In contrast, the slurry bed has large heat capacity of the liquid medium, the heat generated by the propane oxidation reaction is uniformly distributed in the reactor, the catalyst bed is not easy to fly to temperature, and the fine particle catalyst is used, so that the problems of over high local hot spots, easy carbon deposition and the like in the tubular fixed bed reaction process are effectively solved.

In slurry bed reactors, the deep oxidation reaction of the product cannot be suppressed by adjusting the catalyst concentration of the different reaction stages, as compared with the fixed bed reaction process. In order to further improve the selectivity of the product, the selectivity of the acrylic acid is improved by means of regulating and controlling the surface acidity of the catalyst. The doping of the element B reduces the acid strength of the strong acid center and the weak acid center on the surface of the catalyst, reduces the total acid integration amount, and plays a role in inhibiting the deep oxidation of the product acrylic acid. The reasonable distribution of the Mo-V-Te-Nb-B active center and the nickel molybdate active center in the surface crystal structure can mutually and cooperatively act on reactant and intermediate product molecules, and complete the process of converting propane into acrylic acid, so that the catalyst has proper surface acidity and redox capacity, forms good redox conversion and is a necessary factor with higher catalytic activity.

Drawings

FIG. 1 is H of the catalysts obtained in example 2 and comparative example 2 ₂ TPR meterAnd (5) a sign graph.

FIG. 2 is NH of the catalyst obtained in example 2 and comparative example 1 ₃ -TPD characterization map.

Detailed Description

The present invention will be specifically described below by way of examples. It is noted herein that the following examples are given solely for the purpose of illustration and are not to be construed as limiting the scope of the invention, as many insubstantial modifications and variations of the invention will become apparent to those skilled in the art in light of the above disclosure.

Example 1

Preparation of catalyst 1

The first step: preparation of catalyst slurry 1-1 according to the invention by dissolution-Co-precipitation

141.5g of ammonium heptamolybdate, 22.2g of ammonium metavanadate, 39.9 g of telluric acid, 0.3 g of boric acid and 40ml of water are added into a No. 1 beaker, the mixture is stirred at 75-80 ℃ to be dissolved, 82.2g of niobium oxalate and 100ml of distilled water are added into a No. 2 beaker and stirred at 75-80 ℃ to be dissolved, then the solution in the No. 2 beaker is slowly dripped into the No. 1 beaker, distilled water is continuously added to 100ml, and the mixture reacts for 2 hours at normal pressure to prepare the multi-component-containing composite metal oxide catalyst slurry 1-1;

and a second step of: preparation of Nickel molybdate Components 1-2

In a beaker No. 3, 25g of oxalic acid, 12.7g of ammonium heptamolybdate and 50ml of deionized water are uniformly mixed in a beaker of 100 ml; 3.0g of nickel nitrate was dissolved in 10ml of deionized water in a beaker No. 4; then the solution in the No. 4 beaker is dripped into a No. 3 beaker, the PH value of the solution is regulated to be 2 by ammonia water, and the solution is mixed and then reacts for 2.5 hours at the temperature of 55-60 ℃ under normal pressure to obtain slurry containing nickel molybdate; drying the slurry 1-2 in an oven at 80 ℃ for 16 hours at constant temperature, continuously drying at 120 ℃ for 1.5 hours, grinding and crushing to form 50-100 mesh particles, namely the nickel molybdate component 1-2;

and a third step of: preparation of the catalyst

The slurry 1-1 is dried, crushed and ground to form 50-100 meshes of active component particles 1-3, the active component particles 1-3 are mixed with 1-2, silica sol and deionized water are added into the mixture after dry mixing for 1.0h to form a slurry material, the addition amount of the silica sol is 20% of the mass of the solid powder, the addition amount of the deionized water is 40% of the mass of the solid powder, the slurry material is subjected to spray drying at 180 ℃, roasting at 200 ℃ in air atmosphere for 3h, roasting at 650 ℃ in nitrogen atmosphere for 2h, and screening to obtain 40-80 meshes of catalyst particles, so that the catalyst 1, mo: v: te: nb: ni: b=10.1: 2.2:2.0:1.8:0.1:0.06.

fourth step: performance test of catalyst 1

The method for preparing acrylic acid by oxidizing propane comprises the following steps: 10ml of catalyst is filled into a slurry bed reactor, liquid paraffin is adopted as an inert medium, catalyst particles are suspended in the inert medium of the liquid paraffin under the condition of stirring, deionized water is vaporized by a heating pipe at 150 ℃, then is mixed with propane, oxygen and nitrogen, raw materials pass through the slurry bed reactor in a bubbling mode, oxidation reaction is carried out for 24 hours according to the conditions listed in the table 1, and the target product acrylic acid can be obtained after condensation and collection of the product, and the test results are shown in the table 2.

TABLE 1 Process parameters for the preparation of acrylic acid by the oxidation of propane

TABLE 2

Example 2

Preparation of catalyst 2

The procedure for the preparation of catalyst 2 was as in example 1.

And a second step of: preparation of Nickel molybdate Components 1-2

In a beaker No. 3, 8g of oxalic acid, 12.7g of ammonium heptamolybdate and 50ml of deionized water are uniformly mixed in a beaker of 100 ml; 3.0g of nickel nitrate was dissolved in 10ml of deionized water in a beaker No. 4; then the solution in the No. 4 beaker is dripped into the No. 3 beaker, the PH value of the solution is regulated to be 5 by ammonia water, and the solution is mixed and then reacts for 2.5 hours at the temperature of 55-60 ℃ under normal pressure to obtain slurry containing nickel molybdate; drying the slurry 1-2 in an oven at 80 ℃ for 16 hours at constant temperature, continuously drying at 120 ℃ for 1.5 hours, grinding and crushing to form 50-100 mesh particles, namely the nickel molybdate component 1-2;

and a third step of: preparation of finished catalyst 2

Drying the active component particles obtained in the first step, crushing and grinding to form 50-100 meshes of active component particles 1-3, mixing the active component particles with the nickel molybdate obtained in the second step, adding the active component particles into a kneading device, dry-mixing for 1.0h, adding deionized water and silica sol into the mixture to form a slurry material, wherein the addition amount of the silica sol is 10% of the mass of the solid powder, the addition amount of the deionized water is 30% of the mass of the solid powder, spray-drying the slurry material at 180 ℃, roasting for 2 hours in a nitrogen atmosphere at 600 ℃, screening to obtain 40-80 meshes of catalyst particles, and obtaining a catalyst 2, wherein the catalyst 2 comprises the following components: v: te: nb: ni: b=10.1: 2.2:2.0:1.8:0.1:0.06. the oxidation reaction was carried out for 24 hours according to condition 2 listed in table 1, and the test result data are shown in table 5.

Comparative example D1

The difference from example 2 is that the catalyst slurry 1-1 was prepared by the dissolution-coprecipitation method in the first step, boric acid was not added, and the addition amounts of other substances were the same; then mixing with nickel molybdate component 1-2 to prepare a comparative catalyst D1, wherein the composition of the prepared catalyst is Mo: v: te: nb: ni=10.1: 2.2:2.0:1.8:0.1. the oxidation reaction was carried out for 24 hours according to condition 2 listed in table 1, and the test result data are shown in table 5.

Comparative example D2

The same amount of catalyst slurry 1-1 was added as in example 2, the catalyst slurry prepared by the dissolution-coprecipitation method in the first step, except that the nickel molybdate prepared in the second step was not present, and the catalyst preparation method in the third step was as follows: the slurry 1-1 is dried, crushed and ground to form 50-100 mesh active component particles 1-3, silica sol and deionized water are added to form slurry materials, and the slurry materials are subjected to spray drying at 180 ℃, roasting at 200 ℃ in air atmosphere for 3 hours and roasting at 650 ℃ in nitrogen atmosphere for 2 hours, and are sieved to obtain 40-80 mesh catalyst particles, so that a comparative catalyst D2 is prepared, and the composition of the catalyst is Mo: v: te: nb: b=9.8: 2.3:2.1:1.9:0.06. the oxidation reaction was carried out for 24 hours according to condition 2 listed in table 1, and the test result data are shown in table 5.

Comparative example D3

Adding 154.2g of ammonium tetramolybdate, 28.6g of ammonium metavanadate, 54.0 g of telluric acid and 40ml of water into a No. 1 beaker, stirring the mixture at 75-80 ℃ to dissolve the mixture, adding 109.8g of niobium oxalate and 50ml of distilled water into a No. 2 beaker to dissolve the mixture, slowly dripping the solution in the No. 2 beaker into the No. 1 beaker, continuously adding distilled water to 100ml, and reacting for 2 hours at normal pressure to obtain multi-component composite metal oxide catalyst slurry;

drying the slurry, crushing and grinding to form 50-100 mesh active component particles; adding silica sol into the active component particles, wherein the addition amount of the silica sol is 20% of the mass of the active component particles, and the addition amount of water is 40% of the mass of the active component particles, and kneading to form paste; spray drying the slurry material at 180 ℃, roasting for 3 hours in an air atmosphere at 200 ℃ and roasting for 2 hours in a nitrogen atmosphere at 600 ℃, and screening to obtain 40-80-mesh catalyst particles, so as to prepare a catalyst D3, wherein Mo: v: te: nb=9.8: 2.4:2.3:2.0;

catalyst D3 was subjected to a performance test for synthesizing acrylic acid from propane, and an oxidation reaction was carried out for 24 hours under condition 2 shown in Table 1, and the test result data are shown in Table 5.

Comparative example D4

The first step is the same as in example 2, and the active ingredient particles obtained in the first step are crushed and ground after being dried, so that the whole block forms active ingredient particles 1-3 of 50-100 meshes.

And a second step of: commercial nickel molybdate (manufacturer: alfa, cat# 089938, purity 98%)

Uniformly mixing 2.2g of nickel molybdate with 1-3 active component particles prepared in the first step, adding into a kneading device, dry-mixing for 1.0h, adding deionized water and silica sol into the mixture to form a pasty material, wherein the addition amount of the silica sol is 10% of the mass of the solid powder, the addition amount of the deionized water is 30% of the mass of the solid powder, spray-drying the pasty material at 180 ℃, roasting for 2 hours in a nitrogen atmosphere at 600 ℃, screening to obtain 40-80 mesh catalyst particles, and preparing the catalyst, wherein the catalyst comprises the following components of Mo: v: te: nb: ni: b=10.0: 2.3:2.1:1.9:0.12:0.06.

the catalyst performance was evaluated according to the catalyst performance test method of example 2, and the experimental results are shown in table 5.

FIG. 1 is H of example 2 and comparative example 2 ₂ -a TPR profile; table 3 is XPS characterization data for example 2 and comparative example 2; FIG. 2 is NH of example 2 and comparative example 1 ₃ -a TPD characterization map; table 4 is the catalyst surface acid amount integration data for example 2 and comparative example 1;

as can be seen from FIGS. 1 and 3, the introduction of nickel molybdate plays a role in adjusting the content of metals with different valence states on the surface of the catalyst, so that the high valence state element Mo in the catalyst ⁶⁺ 、V ⁵⁺ And Ni ²⁺ The content is increased, and the oxidation-reduction capability of the catalyst is enhanced; as can be seen from fig. 2 and table 4, the catalyst contained two ammonia desorption peaks before B addition, whose peak top temperatures of desorption were near 190 ℃ and 450 ℃ respectively, indicating that both weak acid centers and strong acid centers were present on the catalyst surface. After B is added, the desorption temperatures of the weak acid site and the strong acid site are gradually reduced, so that the doping of B introduced elements reduces the center strength of strong acid and weak acid in the catalyst, the total acid amount of the catalyst surface is obtained through calculation (table 4), and the introduction of B elements reduces the total acid amount of the catalyst surface, so that the acrylic acid selectivity is improved.

TABLE 3 XPS test results for catalysts

TABLE 4 integration of the surface acidity of the catalysts

Example 3

Preparation of catalyst 3

The preparation procedure of catalyst 3 was the same as in example 1 in the first and third steps.

And a second step of: preparation of Nickel molybdate Components 1-2

Uniformly mixing 20g of citric acid, 12.7g of ammonium molybdate and 50ml of deionized water in a beaker No. 3 in a 100ml beaker; 3.0g of nickel nitrate was dissolved in 10ml of deionized water in a beaker No. 4; then the solution in the No. 4 beaker is dripped into a No. 3 beaker, the PH value of the solution is regulated to be 3 by ammonia water, and the solution is mixed and then reacts for 1h at the temperature of 55-60 ℃ under normal pressure to obtain slurry containing nickel molybdate; drying the slurry 1-2 at 120 ℃ for 10 hours, grinding and crushing to form 50-100 mesh particles, namely the nickel molybdate component 1-2;

the composition of the catalyst 3 prepared was: mo: v: te: nb: ni: b=10.1: 2.2:2.0:1.8:0.1:0.06.

the oxidation reaction was carried out for 24 hours according to condition 1 listed in table 1, and the test result data are shown in table 5.

Example 4

Preparation of catalyst 4

Adding 156.9g of ammonium tetramolybdate, 35.5g of vanadyl oxalate, 55.0 g of telluric acid, 4.4 g of boric anhydride and 200ml of water into a No. 1 beaker, stirring the mixture at 75-80 ℃ to dissolve the mixture, adding 61.5g of ammonium niobium oxalate and 100ml of distilled water into a No. 2 beaker, stirring the mixture at 75-80 ℃ to dissolve the mixture, then slowly dripping the solution in the No. 2 beaker into the No. 1 beaker, continuously adding distilled water to 100ml, and reacting the mixture at normal pressure for 2 hours to prepare a multi-component-containing composite metal oxide catalyst slurry 1-1;

and a second step of: preparation of Nickel molybdate Components 1-2

In a beaker No. 3, 25g of oxalic acid, 8.2g of ammonium tetramolybdate and 50ml of deionized water are uniformly mixed in a beaker of 100 ml; 15.1g nickel nitrate was dissolved in 10ml deionized water in a beaker No. 4; then the solution in the No. 4 beaker is dripped into the No. 3 beaker, the PH value of the solution is regulated to be 4 by ammonia water, and the solution is mixed and then reacts for 2.5 hours at the temperature of 55-60 ℃ under normal pressure to obtain slurry containing nickel molybdate; drying the slurry 1-2 in an oven at 80 ℃ for 16 hours at constant temperature, continuously drying at 120 ℃ for 1.5 hours, grinding and crushing to form 50-100 mesh particles, namely the nickel molybdate component 1-2;

and a third step of: preparation of the catalyst

The slurry 1-1 is dried, crushed and ground to form 50-100 meshes of active component particles 1-3, the active component particles 1-3 are mixed with 1-2, silica sol and deionized water are added into the mixture after dry mixing for 1.0h to form a slurry material, the addition amount of the silica sol is 20% of the mass of the solid powder, the addition amount of the deionized water is 40% of the mass of the solid powder, the slurry material is subjected to spray drying at 180 ℃, roasting at 200 ℃ in air atmosphere for 3h and roasting at 650 ℃ in nitrogen atmosphere for 2h, and 40-80 meshes of catalyst particles are obtained by screening, so as to obtain a catalyst, wherein Mo, V, te, nb: ni: the molar ratio of B is 10.1:2.2:2.3:1.92:0.5:0.84.

the oxidation reaction was carried out for 24 hours according to condition 4 listed in table 1, and the test result data are shown in table 5.

Example 5

Preparation of catalyst 5

Adding 156.9g of ammonium tetramolybdate, 43.7g of vanadyl oxalate, 59.4 g of telluric acid, 2.9 g of boric anhydride and 200ml of water into a No. 1 beaker, stirring the mixture at 75-80 ℃ to dissolve the mixture, adding 67.7g of ammonium niobium oxalate and 100ml of distilled water into a No. 2 beaker, stirring the mixture at 75-80 ℃ to dissolve the mixture, then slowly dripping the solution in the No. 2 beaker into the No. 1 beaker, continuously adding distilled water to 100ml, and reacting the mixture at normal pressure for 2 hours to prepare a multi-component-containing composite metal oxide catalyst slurry 1-1;

and a second step of: preparation of Nickel molybdate Components 1-2

In a beaker No. 3, 20g of oxalic acid, 9.2g of ammonium tetramolybdate and 50ml of deionized water are uniformly mixed in a beaker of 100 ml; 34.2g nickel nitrate was dissolved in 10ml deionized water in a beaker No. 4; then the solution in the No. 4 beaker is dripped into the No. 3 beaker, the PH value of the solution is regulated to be 4 by ammonia water, and the solution is mixed and then reacts for 2.5 hours at the temperature of 55-60 ℃ under normal pressure to obtain slurry containing nickel molybdate; drying the slurry 1-2 in an oven at 80 ℃ for 16 hours at constant temperature, continuously drying at 120 ℃ for 1.5 hours, grinding and crushing to form 50-100 mesh particles, namely the nickel molybdate component 1-2;

and a third step of: preparation of the catalyst

The slurry 1-1 is dried, crushed and ground to form 50-100 meshes of active component particles 1-3, the active component particles 1-3 are mixed with 1-2, silica sol and deionized water are added into the mixture after dry mixing for 1.0h to form a slurry material, the addition amount of the silica sol is 20% of the mass of the solid powder, the addition amount of the deionized water is 40% of the mass of the solid powder, the slurry material is subjected to spray drying at 180 ℃, roasting at 200 ℃ in air atmosphere for 3h and roasting at 650 ℃ in nitrogen atmosphere for 2h, and 40-80 meshes of catalyst particles are obtained by screening, so as to obtain a catalyst, wherein Mo, V, te, nb: ni: the molar ratio of B is 9.5:2.5:2.3:2.0:1.0:0.5.

Example 6

Preparation of catalyst 6

141.5g of ammonium heptamolybdate, 22.2g of ammonium metavanadate, 43.6 g of telluric acid, 1.6 g of boric acid and 200ml of water, stirring the mixture at 75-80 ℃ to dissolve the mixture, adding 93.2g of niobium oxalate into a No. 2 beaker, stirring 200ml of distilled water at 75-80 ℃ to dissolve the mixture, slowly dripping the solution in the No. 2 beaker into a No. 1 beaker, continuously adding distilled water to 100ml, and reacting for 2 hours at normal pressure to prepare the multi-component-containing composite metal oxide catalyst slurry 1-1;

and a second step of: preparation of Nickel molybdate Components 1-2

15g oxalic acid, 6.7g ammonium heptamolybdate and 50ml deionized water were mixed well in a beaker No. 3 in a 100ml beaker; 11.0g of nickel nitrate was dissolved in 10ml of deionized water in a beaker No. 4; then the solution in the No. 4 beaker is dripped into the No. 3 beaker, the PH value of the solution is regulated to be 4 by ammonia water, and the solution is mixed and then reacts for 2.5 hours at the temperature of 55-60 ℃ under normal pressure to obtain slurry containing nickel molybdate; drying the slurry 1-2 in an oven at 80 ℃ for 16 hours at constant temperature, continuously drying at 120 ℃ for 1.5 hours, grinding and crushing to form 50-100 mesh particles, namely the nickel molybdate component 1-2;

and a third step of: preparation of the catalyst

The slurry 1-1 is dried, crushed and ground to form 50-100 meshes of active component particles 1-3, the active component particles 1-3 are mixed with 1-2, silica sol and deionized water are added into the mixture after dry mixing for 1.0h to form a slurry material, the addition amount of the silica sol is 20% of the mass of the solid powder, the addition amount of the deionized water is 40% of the mass of the solid powder, the slurry material is subjected to spray drying at 180 ℃ and roasting for 2 hours in a nitrogen atmosphere at 650 ℃, and 40-80 meshes of catalyst particles are obtained by screening, so as to obtain a catalyst, wherein Mo, V, te, nb: ni: the molar ratio of B is 9.6:2.2:2.2:1.9:0.4:0.3.

the oxidation reaction was carried out for 24 hours according to condition 2 listed in table 1, and the test result data are shown in table 5.

TABLE 5

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A catalyst for the catalytic production of acrylic acid from propane, characterized in that the catalyst is represented by the general formula:

Mo _a V _b Te _c Nb _d Ni _e B _f O _x

2. The catalyst for the catalytic production of acrylic acid from propane according to claim 1, characterized in that it is prepared by the following method:

3. The catalyst for the catalytic production of acrylic acid from propane according to claim 2, wherein the baking temperature in step 3) is 600 ℃ or higher.

4. The catalyst for the catalytic production of acrylic acid from propane according to claim 2, wherein the organic acid, the nickel source, the molybdenum source and the deionized water in step 2) are mixed at a pH ranging from 2 to 5.

5. The catalyst for preparing acrylic acid by catalyzing propane according to claim 2, wherein in the step 1), the molybdate is one of ammonium heptamolybdate and ammonium tetramolybdate, the vanadate is one of ammonium metavanadate and vanadyl oxalate, the tellurium compound is one of telluric acid and tellurium dioxide, the niobium salt is one of niobium oxalate, niobium acetate and ammonium niobium oxalate, and the boride is boric anhydride or boric acid; the organic acid in the step 2) is one of oxalic acid and citric acid, and the nickel salt is one of nickel acetate, nickel nitrate and basic nickel carbonate.

6. The catalyst for preparing acrylic acid by catalyzing propane according to claim 2, wherein the binder in the step 3) is one or more of silica sol, aluminum sol and silica-alumina sol, preferably silica sol.

7. The catalyst for the catalytic production of acrylic acid from propane according to claim 2, wherein in step 3), the binder is added in an amount of 10 to 20wt% based on the total amount of Mo-V-Te-Nb-B component and nickel molybdate component, and the deionized water is added in an amount of 30 to 40wt% based on the total amount of Mo-V-Te-Nb-B component and nickel molybdate component.

8. Use of the catalyst according to any one of claims 1 to 7 in a slurry bed reactor, wherein a mixture of deionized water, propane, oxygen and nitrogen is bubbled through a slurry layer of catalyst fines suspended in the slurry bed, the slurry temperature in the slurry bed reactor being from 430 ℃ to 500 ℃.

9. Use of the catalyst according to claim 8 in a slurry bed reactor, wherein the total mass space velocity during the reaction is 1000 ml/(g.h) to 3000 ml/(g.h), oxygen/propane volume ratio = 1 to 5, water/propane volume ratio = 1 to 5, balance nitrogen.

10. Use of a catalyst according to claim 8 in a slurry bed reactor, characterized in that propane is 5-15 vol% of the total gas.