CN111054409B - Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane - Google Patents

Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane Download PDF

Info

Publication number
CN111054409B
CN111054409B CN201811203017.1A CN201811203017A CN111054409B CN 111054409 B CN111054409 B CN 111054409B CN 201811203017 A CN201811203017 A CN 201811203017A CN 111054409 B CN111054409 B CN 111054409B
Authority
CN
China
Prior art keywords
catalyst
temperature
catalyst precursor
activation
hours
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201811203017.1A
Other languages
Chinese (zh)
Other versions
CN111054409A (en
Inventor
张东顺
师慧敏
张作峰
冯晔
安欣
袁滨
刘玉芬
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
Original Assignee
Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sinopec Beijing Research Institute of Chemical Industry, China Petroleum and Chemical Corp filed Critical Sinopec Beijing Research Institute of Chemical Industry
Priority to CN201811203017.1A priority Critical patent/CN111054409B/en
Publication of CN111054409A publication Critical patent/CN111054409A/en
Application granted granted Critical
Publication of CN111054409B publication Critical patent/CN111054409B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/14—Phosphorus; Compounds thereof
    • B01J27/186—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J27/195—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with vanadium, niobium or tantalum
    • B01J27/198—Vanadium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/28—Phosphorising
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
    • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
    • C07D307/56—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D307/60—Two oxygen atoms, e.g. succinic anhydride

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Catalysts (AREA)

Abstract

The invention relates to an activation method of a catalyst for preparing maleic anhydride by oxidizing n-butane, which comprises the following steps: step S1, heating a VPO catalyst precursor to 380-480 ℃, wherein when the temperature is raised to 120-270 ℃, a first active atmosphere is introduced to perform first-step activation on the catalyst precursor in the first active atmosphere, wherein the first active atmosphere consists of a mixture of oxygen and nitrogen and/or air and water vapor; and step S2, keeping the VPO catalyst precursor treated in the step S1 in a first active atmosphere at 380-480 ℃ for a first time, and then keeping in a second active atmosphere at 380-480 ℃ for a second time to perform second-step activation, wherein the second active atmosphere consists of water vapor and inert gas. The activation method adopted by the invention is simple, rapid and easy to operate, and the activation efficiency and stability of the VPO catalyst are improved.

Description

Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane
Technical Field
The invention belongs to the technical field of maleic anhydride (maleic anhydride for short) catalyst prepared by oxidizing n-butane, and particularly relates to an activation method of maleic anhydride catalyst prepared by oxidizing n-butane.
Background
Maleic anhydride is a very important organic chemical raw material, and becomes the second largest organic anhydride which is only next to phthalic anhydride. The maleic anhydride is mainly used for producing 1, 4-butanediol, gamma-butyrolactone, tetrahydrofuran, fumaric acid, unsaturated polyester resin and the like, and can also be used for producing medicines and pesticides.
The maleic anhydride production abroad is mainly based on the n-butane technology, the capacity of the n-butane method in China is continuously expanded in recent years, the capacity of the maleic anhydride production in China is over 60 percent at present, and the operating rate of the maleic anhydride production is higher than that of the benzene method. Most normal butane devices in China are reconstructed or transformed from benzene method devices, so that oxidation units mainly comprise fixed bed tubular reactors, tail gas after reaction adopts a partial condensation method and water absorption; maleic anhydride was purified by azeotropic distillation. Therefore, the butane method has a mature production process, but China has no domestic catalyst application on the aspect of a core technology catalyst, so that the market price of the imported catalyst is too high, and the domestic market is monopolized.
The development of an industrialized VPO catalyst with independent intellectual property rights is of great significance. Not only can break the monopoly of foreign technologies, reduce the price of the catalyst and reduce the cost of enterprises; can also improve the technical level and innovation ability of China in the aspect of oxidation catalysts. Currently, the VPO catalysts used in industry are prepared with vanadium and phosphorus as main components, supplemented with appropriate auxiliaries. In the catalyst production process, there are two main steps, the first is the synthesis of the precursor, i.e. the synthesis of the hemihydrate compound VOHPO 4 ·0.5H 2 O; second, activation of the precursor, i.e. the hemihydrate VOHPO 4 ·0.5H 2 Conversion of O to vanadyl pyrophosphate (VO) 2 P 2 O 7 . Wherein the activation is to convert the vanadium phosphorus oxide hemihydrate precursor to a VPO catalyst having an activity and selectivity under certain conditions. Thus, the activation process is directed to the formation of vanadium phosphorus oxygenHas very important significance.
CN106540728A discloses an activation method of VPO catalyst used in preparation of maleic anhydride by oxidation of n-butane. The method for activating the catalyst includes a first activation step to a third activation step, a cooling step, and the like. In the first activation stage, the temperature of the catalyst is raised from room temperature to 200-220 ℃, the temperature rise rate is 5-60 ℃/h, and the space velocity is 1-3000h -1 The activating atmosphere is one or two of air, n-butane and water vapor, and the time is 0.5-10 hours; in the second activation stage, the temperature is raised to 360-380 ℃ at the speed of 5-60 ℃/h, and the activation is carried out for 0.5-10 hours at the temperature; and a third activation step, namely, raising the temperature to 400-500 ℃ at a speed of 5-60 ℃/h, and activating for 0.5-10 hours at the temperature, wherein the used gas is one or two of air, n-butane and water vapor. Finally, the temperature is reduced to a certain temperature in the atmosphere with the normal butane concentration of 1-2 percent to obtain the activated VPO catalyst. The activation process can obtain a catalyst with better performance, but the activation time of the process is too long, generally more than 24 hours, in some cases more than 47 hours, and the activation in a material carrying device is needed, so the operation process is more complicated.
For the hemihydrate VOHPO 4 ·0.5H 2 Conversion of O to vanadyl pyrophosphate (VO) 2 P 2 O 7 Have been extensively and extensively studied by scientists and engineers. However, the process still has many problems, and the inventor finds that the catalysts activated according to the prior art have deactivation phenomena in the using process, the normal butane conversion rate is reduced along with the prolonging of the evaluation time, and if the service life cannot reach a certain time, the activated catalysts lose the value of industrial application.
Disclosure of Invention
The present invention is based on the following findings of the inventors: in the catalyst activation process, water vapor is introduced at 120-270 ℃, which is beneficial to forming a catalyst with good crystal form. Further, the inventors found that in XRD detection, when 2 θ is 22.9 ° (crystal structure (020) plane, peak intensity is represented as I 1 ) And 28.5 ° (crystal structure (204) plane, peak intensity is noted as I 2 ) Is/are as followsRelative intensity of diffraction peaks (in I) 1 /I 2 Measured) is between 1.0 and 1.5, the catalyst has stable performance, and the service life of the catalyst is obviously prolonged.
The invention aims to improve and improve the activation method of the catalyst for preparing maleic anhydride by oxidizing n-butane, adopts a quick, simple and easy-to-operate method to activate the catalyst, and enables the catalyst to have preferred crystal face orientation, thereby being capable of keeping the stability of performance and avoiding the phenomenon of activity reduction in more than 30 days.
To this end, in a first aspect, the present invention provides a rapid, simple and easy-to-operate activation method of a catalyst for preparing maleic anhydride by oxidation of n-butane, which improves the activation efficiency and stability of a VPO catalyst, and allows the catalyst to have a preferred crystal plane orientation, and can save time and reduce production costs.
The activation method of the catalyst for preparing maleic anhydride by oxidizing n-butane provided by the invention comprises the following steps:
step S1, heating a VPO catalyst precursor to 380-480 ℃, wherein when the temperature is raised to 120-270 ℃, a first active atmosphere is introduced to perform first-step activation on the catalyst precursor in the first active atmosphere, wherein the first active atmosphere consists of a mixture of oxygen and nitrogen and/or air and water vapor;
and step S2, keeping the VPO catalyst precursor treated in the step S1 at 380-480 ℃ in a first active atmosphere for a first time, and then keeping at 380-480 ℃ in a second active atmosphere consisting of water vapor and inert gas for a second time to perform second-step activation.
According to some embodiments of the invention, in step S1, a first reactive atmosphere is introduced while raising the temperature to a temperature in the range of 150 to 250 ℃, preferably 175 to 225 ℃.
According to some embodiments of the present invention, in step S1, the temperature rise rate is 0.5-10 deg.C/min, preferably 2-10 deg.C/min, more preferably 3-8 deg.C/min.
According to some embodiments of the invention, the first activating atmosphere has a volume fraction of water vapor of 20-70% and a volume fraction of air of 80-30%; preferably, the first activating atmosphere has a volume fraction of water vapour of 40-60% and a volume fraction of air of 60-40%.
According to some embodiments of the invention, the first reactive atmosphere has a volumetric space velocity of 100 to 1500h -1 Preferably 500-1200h -1 。
According to some embodiments of the invention, in step S2, the first time is 1 to 5 hours and the second time is 3 to 8 hours.
According to some embodiments of the present invention, in the second activated atmosphere, the inert gas is nitrogen, helium, carbon dioxide, or a mixture of at least two of the three.
According to some embodiments of the invention, the volume fraction of water vapour in the second activating atmosphere is between 20 and 70%, preferably between 40 and 60%.
According to some embodiments of the invention, the method for preparing a VPO catalyst precursor comprises the steps of:
1) Mixing a vanadium compound, phosphoric acid, oxalic acid, an auxiliary agent and isobutanol, and heating and refluxing, preferably refluxing for 8-24 hours;
2) Carrying out solid-liquid separation on the mixture obtained in the step 1), and then washing the mixture by using an organic solvent to obtain a solid catalyst precursor containing a certain amount of the organic solvent;
3) Drying the solid catalyst precursor obtained in step 2), preferably at a temperature of 60-90 ℃ for a period of 12-36 hours, for example 24 hours;
4) Roasting the dried catalyst precursor obtained in the step 3), wherein the roasting temperature is preferably 200-250 ℃ and the roasting time is 3-10 hours;
5) Pressing the calcined catalyst precursor obtained in the step 4) into a certain shape to obtain the VPO catalyst precursor.
According to some embodiments of the invention, the VPO catalyst precursor is a hemihydrate VOHPO comprising 1-4% by mass of graphite 4 ·0.5H 2 O, graphite is added in powder form before or after synthesis of the VPO catalyst precursor, and the particle size is 6-20 mu m.
According to some embodiments of the invention, the VPO catalyst precursor is spherical, cloverleaf, flake, cylindrical or hollow cylindrical in shape and has a size of 2-12mm.
The activation method of the present invention can obtain a crystal structure (020) plane having a 2 θ of 22.9 ° (peak intensity is represented as I) 1 ) And 28.5 ° (crystal structure (204) plane, peak intensity is noted as I 2 ) Relative intensity of diffraction peak of (in I) 1 /I 2 Calculated) between 1.0 and 1.5 VPO catalyst.
In a second aspect, the present invention provides the use of a VPO catalyst activated according to the above activation process for the oxidation of n-butane to produce maleic anhydride.
The VPO catalyst prepared by the activation method of the invention is suitable for fixed bed tubular or tubular reactors. The VPO catalyst activated by the method is adopted in a 120mL single-tube device, the conversion rate of normal butane can reach more than 84%, the weight yield of maleic anhydride can reach more than 95%, and the method has a very good industrial application prospect.
The use of the activated catalyst of the invention has the following technical advantages:
1) The method has few steps and simple operation. In the present invention, the activation step is only two steps, and the selection of the activation atmosphere is less.
2) Short activation time and high activation efficiency. Two-step activation is adopted, so that the heating rate can be properly increased in the first-step activation stage, and the activation time is shortened; less time can be used in the second activation stage with the phase transition ensured.
3) And a plurality of gases do not need to be mixed and proportioned, so that the cost is reduced and the resources are saved. Only a few gases such as air, nitrogen, water vapor and the like are needed in the activation process, and the cost is low.
4) The performance index of the catalyst is excellent, and XRD shows that I 1 /I 2 The catalyst has good selectivity and higher stability between 1.0 and 1.5.
Drawings
FIG. 1 XRD pattern of catalyst A prepared in example 1;
FIG. 2 is a graph of the conversion of catalyst A prepared in example 1 as a function of time;
FIG. 3 XRD pattern of catalyst B prepared in example 2;
FIG. 4 is a graph of the conversion of catalyst B prepared in example 2 as a function of time;
FIG. 5 XRD pattern of catalyst C prepared in example 3;
FIG. 6 is a graph of the conversion of catalyst C prepared in example 3 as a function of time;
FIG. 7 XRD pattern of catalyst D prepared in example 4;
FIG. 8 is a graph of the conversion of catalyst D prepared in example 4 as a function of time;
FIG. 9 XRD pattern of catalyst E prepared in example 5;
FIG. 10 is a graph of the conversion of catalyst E prepared in example 5 as a function of time;
FIG. 11 XRD pattern of catalyst F prepared in comparative example 1;
FIG. 12 is a graph of the conversion of catalyst F prepared in comparative example 1 as a function of time;
FIG. 13 XRD pattern of catalyst G prepared in comparative example 2;
FIG. 14 is a graph of the conversion of catalyst G prepared in comparative example 2 as a function of time;
FIG. 15 XRD pattern of catalyst H prepared in comparative example 3;
FIG. 16 is a graph showing the change in H conversion of the catalyst prepared in comparative example 3 with time.
Detailed Description
The invention is further illustrated by the following examples. These examples are illustrative and exemplary of the present invention and are not intended to limit the scope of the present invention in any way.
Synthesis of catalyst precursor:
mixing 100g of V 2 O 5 60g of oxalic acid, 16g of ZnSO 4 Placing in a 3L three-necked flask, adding 1000mL of isobutanol, heating the mixture to reflux temperature, refluxing for 1 hour, cooling to room temperature, adding 120g of 105% phosphoric acid dropwise under stirring, refluxing for 20 hours to obtain a catalyst slurry, centrifuging the slurry, washing with anhydrous ethanol for several times,then the catalyst is dried in a 60 ℃ oven for 24 hours, and then transferred to a muffle furnace, calcined at 200 ℃ for 5 hours, and the calcined catalyst powder is mixed with 4% graphite and pressed into a cloverleaf shape to obtain a catalyst precursor.
The catalyst evaluation method comprises the following steps:
mixing the activated catalyst with stearic acid, wherein the mass fraction of the stearic acid is 2-15%, the stearic acid is used as a pore-forming agent and mainly forms macropores, and the desorption adopts a decompression low-temperature desorption mode, and the method comprises the following steps:
1) Mixing the activated catalyst precursor with stearic acid, and pressing to obtain a molded catalyst for evaluation, wherein the catalyst can be in a hollow cylindrical shape or a cloverleaf shape;
2) Putting the catalyst in a vacuum drying oven, keeping the vacuum degree of 0-0.1MPa and the temperature of 140-200 ℃ for 3-24 hours;
3) Cooling to room temperature for later use.
The catalyst is used for a fixed bed tubular reactor, a thermometer sleeve is inserted in the reaction tube to measure the temperature of a hot spot, and molten salt is adopted for heat exchange to maintain the temperature in the reaction tube within a determined range. The reaction tube had an inner diameter of 21mm and a length of 80cm, and the catalyst loading was 120mL. The volume fraction of n-butane is 1.5-1.8%, and the volume space velocity is 1500-1800h -1 The molten salt temperature was evaluated at 390-415 ℃.
In the invention, the conversion rate of the n-butane is calibrated by adopting a chromatography method, the weight yield of the maleic anhydride is measured by adopting a bypass sampling method, the concentrations of the by-products of the carbon monoxide and the carbon dioxide are calibrated by adopting a TCD method, and the concentration of the n-butane is calibrated by adopting an FID method.
Example 1
The catalyst precursor was placed in a fixed bed reactor, and the packing volume was 150mL and the packing mass was 140g.
First-step activation: the temperature of the catalyst precursor is increased from room temperature to 420 ℃, and the temperature increasing rate is 3 ℃/min; when the temperature of the single-tube bed layer rises to 180 ℃, air and steam are introduced, the introduction amount of the air and the steam is 1.0L/min, and the corresponding air is introduced at the momentThe speed is 800h -1 。
And a second step of activation: the catalyst was held at 420 ℃ for 1 hour, then air was replaced by nitrogen, the flow rate of nitrogen was also 1.0L/min, and water vapor was kept constant and held at this temperature for 6 hours.
Mixing 90g of the activated catalyst with 10g of stearic acid, pressing into a clover shape again, placing the clover shape in a vacuum drying oven, keeping the vacuum degree of the vacuum drying oven at 0.1MPa and the temperature of 160 ℃ for 10 hours, recording the catalyst as A, and displaying XRD results as shown in figure 1, wherein the results show that I is 1 /I 2 Is 1.38.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under conditions of a molten salt temperature of 400-405 ℃ and an n-butane concentration of 1.5-1.8%, and a curve of the conversion rate with time is shown in FIG. 2.
Example 2
The catalyst precursor was placed in a fixed bed reactor, and the packing volume was 150mL and the packing mass was 140g.
The first step of activation: the temperature of the catalyst precursor is raised from room temperature to 430 ℃, the temperature raising rate is 5 ℃/min, when the temperature of a single-tube bed is raised to 225 ℃, air and water vapor are introduced, the introduction amount of the air and the water vapor is 1.25L/min, and the corresponding space velocity is 1000h -1 。
The second step of activation: the catalyst was held at 430 ℃ for 1 hour, then air was replaced by nitrogen, the flow rate of which was also 1.25L/min, and water vapor was held constant and held at this temperature for 8 hours.
Mixing 90g of the activated catalyst with 10g of stearic acid, pressing into clover shape again, placing in a vacuum drying oven, keeping for 10 hours at 185 ℃ under the vacuum degree of 0.1MPa, recording the catalyst as B, and showing XRD result as shown in figure 3 1 /I 2 Was 1.09.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under conditions of a molten salt temperature of 400 to 405 ℃ and an n-butane concentration of 1.5 to 1.8%, and a curve of a change in conversion rate with time is shown in FIG. 4.
Example 3
The catalyst precursor was placed in a fixed bed reactor, and the packing volume was 150mL and the packing mass was 140g.
First-step activation: the temperature of the catalyst precursor is raised to 440 ℃ from room temperature, the temperature raising rate is 5 ℃/min, when the temperature of the single-tube bed layer is raised to 175 ℃, air and water vapor are introduced, the introduction amount of the air and the water vapor is 1.25L/min, and the corresponding space velocity is 1000h at the moment -1 。
And a second step of activation: the catalyst was kept at 440 ℃ for 1 hour, then air was replaced by nitrogen, the flow rate of nitrogen was also 1.0L/min, the flow rate of water vapor was also adjusted to 1.0L/min, and this temperature was kept for 7 hours.
Mixing 90g of the activated catalyst with 10g of stearic acid, pressing into clover shape again, placing in a vacuum drying oven, keeping at 170 ℃ for 10 hours under the vacuum degree of 0.1MPa, recording the catalyst as C, and showing XRD result as shown in figure 5, wherein I is shown 1 /I 2 Was 1.17.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under conditions of a molten salt temperature of 400 to 405 ℃ and an n-butane concentration of 1.5 to 1.8%, and a curve of a change in conversion rate with time is shown in FIG. 6.
Example 4
The catalyst precursor was placed in a fixed bed reactor, and the packed volume was 150mL and the packed mass was 140g.
First-step activation: the temperature of the catalyst precursor is increased from room temperature to 420 ℃, the temperature rising rate is 3 ℃/min, when the temperature of the single-tube bed layer is increased to 225 ℃, air and water vapor are introduced, the introduction amount of the air and the water vapor is 1.0L/min, and the corresponding space velocity is 800h -1 。
And a second step of activation: the catalyst was maintained at 420 ℃ for 1 hour, then air was replaced by nitrogen, the flow rate of nitrogen was also adjusted to 1.0L/min, the flow rate of water vapor was also adjusted to 1.0L/min, and the catalyst was maintained at this temperature for 6 hours.
Mixing 90g of the activated catalyst with 10g of stearic acid, pressing into a clover shape again,and placed in a vacuum drying oven at 160 deg.C for 10 hours under 0.1MPa of vacuum degree, the catalyst is recorded as D, the XRD result is shown in FIG. 7, and the result shows I 1 /I 2 Was 1.13.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under the conditions that the molten salt temperature was 400 to 405 ℃ and the n-butane concentration was 1.5 to 1.8%, and the curve of the conversion rate with time is shown in FIG. 8.
Example 5
The catalyst precursor was placed in a fixed bed reactor, and the packing volume was 150mL and the packing mass was 140g.
First-step activation: the temperature of the catalyst precursor is increased from room temperature to 420 ℃, the temperature rising rate is 3 ℃/min, when the temperature of the single-tube bed layer is increased to 175 ℃, air and water vapor are introduced, the introduction amount of the air and the water vapor is 1.0L/min, and the corresponding space velocity is 800h -1 。
And a second step of activation: the catalyst was maintained at 420 ℃ for 1 hour, then air was replaced with nitrogen, the flow rate of nitrogen was also adjusted to 1.0L/min, and the flow rate of water vapor was also adjusted to 1.0L/min, and maintained at this temperature for 6 hours.
Mixing 90g of the activated catalyst with 10g of stearic acid, pressing into clover shape again, placing in a vacuum drying oven, maintaining at 160 deg.C for 10 hr under 0.1MPa for use, recording as E, and showing XRD result as shown in FIG. 9 1 /I 2 Is 1.26.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under the conditions that the molten salt temperature was 400 to 405 ℃ and the n-butane concentration was 1.5 to 1.8%, and the curve of the conversion rate with time is shown in FIG. 10.
Comparative example 1
The activation method provided by patent CN103357446A is adopted for activation, and the activation is specifically carried out in 800h -1 The catalyst was purged with air at space velocity, then heated to 260 ℃ and held at that temperature for 1 hour, then heated to 405 ℃ under a purge of air and nitrogen for 30 minutes, then addedHeating to 425 ℃ for 2 hours, finally keeping the temperature at 425 ℃ unchanged, and changing the atmosphere into 50 percent by 50 percent of nitrogen: steam, held for 6 hours, then allowed to cool to room temperature, the resulting catalyst was designated F, the XRD results are shown in FIG. 11, and the results show I 1 /I 2 And was 0.689. The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under conditions of a molten salt temperature of 400 to 405 ℃ and an n-butane concentration of 1.5 to 1.8%, and a curve of a change in conversion with time is shown in FIG. 12.
Comparative example 2
The catalyst precursor was placed in a fixed bed reactor, and the packing volume was 150mL and the packing mass was 140g.
First-step activation: the temperature of the catalyst precursor is raised from room temperature to 420 ℃, the temperature raising rate is 3 ℃/min, when the temperature of a single-tube bed is raised to 110 ℃, air and water vapor are introduced, the introduction amount of the air and the water vapor is 1.0L/min, and the corresponding space velocity is 800h -1 。
The second step of activation: the catalyst was maintained at 420 ℃ for 1 hour, then air was replaced with nitrogen, the flow rate of nitrogen was also adjusted to 1.0L/min, and the flow rate of water vapor was also adjusted to 1.0L/min, and maintained at this temperature for 6 hours.
Mixing 90G of the activated catalyst with 10G of stearic acid, pressing into clover shape again, placing in a vacuum drying oven, maintaining at 160 deg.C for 10 hr under 0.1MPa for use, and marking as G, XRD result is shown in FIG. 13, and I is shown 1 /I 2 Is 0.62.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under conditions of a molten salt temperature of 400 to 405 ℃ and an n-butane concentration of 1.5 to 1.8%, and a curve of a change in conversion rate with time is shown in FIG. 14.
Comparative example 3
The catalyst precursor was placed in a fixed bed reactor, and the packing volume was 150mL and the packing mass was 140g.
First-step activation: the temperature of the catalyst precursor is raised from room temperature to 420 ℃, the temperature raising rate is 3 ℃/min, and when the temperature of the single-tube bed layer is raised toAt 280 ℃, introducing air and water vapor, wherein the introduction amount of the air and the water vapor is 1.0L/min, and the corresponding space velocity is 800h -1 。
And a second step of activation: the catalyst was maintained at 420 ℃ for 1 hour, then air was replaced with nitrogen, the flow rate of nitrogen was also adjusted to 1.0L/min, and the flow rate of water vapor was also adjusted to 1.0L/min, and maintained at this temperature for 6 hours.
Mixing 90g of the activated catalyst with 10g of stearic acid, pressing into clover shape again, placing in a vacuum drying oven, keeping at 160 deg.C for 10 hr under 0.1MPa for use, and marking as H, XRD result is shown in FIG. 15, and result shows I 1 /I 2 Is 0.58.
The catalyst from which the pore-forming agent was removed was loaded in a 120mL fixed-bed reactor and evaluated under the conditions that the molten salt temperature was 400 to 405 ℃ and the n-butane concentration was 1.5 to 1.8%, and the curve of the conversion rate with time is shown in FIG. 16.
Catalysts A, B, C, D, E, F, G and H were evaluated according to the method of this patent, and the results are shown in Table 1.
TABLE 1 evaluation results of catalysts
Figure BDA0001830481710000101
Figure BDA0001830481710000111
1. ST-temperature of molten salt, 2, C butane N-butane concentration, 3, C conv N-butane conversion, yield by weight of 4, yield by weight of Yield of Yield-maleic anhydride, selectivity of 5, sele-maleic anhydride, hot spot temperature of 6, H.T., 7, S COx CO and CO 2 Alternative, 8, C balance -carbon balance
From XRD results, it can be seen that the catalyst activated by the present patent corresponds to the XRD structure I 1 /I 2 Is between 1.0 and 1.5, and shows that the (020) crystal face as the active crystal face of the catalyst isThe main crystal face, the catalyst has good reaction activity and very good stability, and the phenomenon that the conversion rate is reduced does not occur for a long time.
It can be seen from table 1 that at a molten salt temperature of 400-405 ℃, the catalysts activated by the method of the present invention (examples 1-5) have substantially equivalent n-butane conversion, maleic anhydride selectivity of about 66%, and maleic anhydride weight yield difference of little, even better than catalyst F, compared to catalyst F (comparative example 1) prepared according to the method provided in patent CN 103357446A. In addition, comparative examples 2 and 3, using catalysts G and H activated at a temperature outside the defined temperature range (120-270 ℃ C.) of the first activation atmosphere in step S1 of the process of the present invention, showed significant reductions in n-butane conversion, maleic anhydride selectivity, and maleic anhydride weight yield. The above shows that the catalyst activated according to the present process has good reaction properties.
From the viewpoint of the service life of the catalyst, the catalyst F is activated according to the method provided in patent CN103357446A, corresponding to I in XRD structure 1 /I 2 Is 0.689. The initial molten salt temperature is 400 ℃, the conversion rate can reach more than 80% in the first two days of the reaction, and then the conversion rate is reduced to 77%; the temperature of the molten salt is continuously increased to 405 ℃, the conversion rate is increased to more than 80 percent, and then the conversion rate is reduced to 77.6 percent; the temperature of the molten salt is continuously increased to 410 ℃, the conversion rate is increased to more than 80 percent and then is reduced to 76.0 percent, and obviously, the catalyst activated by the method has the problem that the conversion rate is continuously reduced, and the long-term stability cannot be maintained. Also, the conversion of catalysts G and H prepared in comparative example 2 and comparative example 3 decreased with time and were both below 80%. The above shows that the catalyst activated according to the present process has a higher conversion.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims (17)

1. An activation method of a catalyst for preparing maleic anhydride by n-butane oxidation comprises the following steps:
step S1, heating a VPO catalyst precursor to 380-480 ℃, wherein when the temperature is raised to 120-270 ℃, a first active atmosphere is introduced to perform first-step activation on the catalyst precursor in the first active atmosphere, wherein the first active atmosphere consists of a mixture of oxygen and nitrogen and/or air and water vapor;
step S2, keeping the VPO catalyst precursor treated in the step S1 in a first active atmosphere at 380-480 ℃ for a first time, and then keeping in a second active atmosphere at 380-480 ℃ for a second time to perform second-step activation, wherein the second active atmosphere consists of water vapor and inert gas;
the VPO catalyst obtained after activation has a peak intensity of I in XRD detection of 22.9 degree when 2 theta is 22 1 ) And 28.5 ° (peak intensity is noted as I) 2 ) Relative intensity of diffraction peak of (in I) 1 /I 2 Meter) is between 1.0 and 1.5.
2. The method according to claim 1, wherein in step S1, a first reactive atmosphere is introduced while raising the temperature to a temperature in the range of 150-250 ℃; and/or in the step S1, the heating rate is 0.5-10 ℃/min.
3. The method according to claim 2, wherein in step S1, a first reactive atmosphere is introduced while raising the temperature to a temperature in the range of 170-225 ℃; and/or in the step S1, the heating rate is 2-10 ℃/min.
4. The method according to claim 3, wherein in step S1, the temperature increase rate is 3-8 ℃/min.
5. The method according to any one of claims 1 to 4, wherein the volume fraction of water vapor in the first reactive atmosphere is 20 to 70% and the volume fraction of air is 80 to 30%.
6. The method of claim 5, wherein the first reactive atmosphere has a water vapor volume fraction of 40-60% and air volume fraction of 60-40%.
7. The method according to any one of claims 1 to 4, wherein the first reactive atmosphere has a volumetric space velocity of from 100 to 1500h -1 。
8. The method of claim 7, wherein the first reactive atmosphere has a volumetric space velocity of 500 to 1200 hours -1 。
9. The method according to any one of claims 1 to 4, wherein in step S2, the first time is 1 to 5 hours and the second time is 3 to 8 hours.
10. The method according to any one of claims 1 to 4, wherein in the second reactive atmosphere, the inert gas is nitrogen or helium; and/or the volume fraction of water vapor in the second reactive atmosphere is 20-70%.
11. The method of claim 10, wherein the volume fraction of water vapor in the second reactive atmosphere is 40-60%.
12. The process according to any of claims 1 to 4, characterized in that the preparation process of the VPO catalyst precursor comprises the steps of:
1) Mixing a vanadium compound, phosphoric acid, oxalic acid, an auxiliary agent and isobutanol, and heating and refluxing;
2) Carrying out solid-liquid separation on the mixture obtained in the step 1), and then washing the mixture by using an organic solvent to obtain a solid catalyst precursor containing a certain amount of the organic solvent;
3) Drying the solid catalyst precursor obtained in the step 2);
4) Roasting the dried catalyst precursor obtained in the step 3);
5) Pressing the calcined catalyst precursor obtained in the step 4) into a certain shape to obtain the VPO catalyst precursor.
13. The method as claimed in claim 12, wherein in the step 1), the reflux is carried out for 8 to 24 hours;
and/or, in the step 3), the drying temperature is 60-90 ℃ and the drying time is 12-36 hours;
and/or, in the step 4), the roasting temperature is 200-250 ℃ and the roasting time is 3-10 hours.
14. The method as claimed in claim 13, wherein the drying time in step 3) is 24 hours.
15. The process of any of claims 1-4, wherein the VPO catalyst precursor is a hemihydrate VOHPO comprising 1-4% graphite by mass 4 ·0.5H 2 O, graphite is added in powder form before or after synthesis of the VPO catalyst precursor, and the particle size is 6-20 mu m.
16. The process of any of claims 1 to 4, wherein the VPO catalyst precursor is in the shape of spheres, cloverleaf, tablets, cylinders or hollow cylinders with dimensions of 2-12mm.
17. Use of a VPO catalyst activated by the activation process according to any one of claims 1-16 in the preparation of maleic anhydride by n-butane oxidation.
CN201811203017.1A 2018-10-16 2018-10-16 Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane Active CN111054409B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811203017.1A CN111054409B (en) 2018-10-16 2018-10-16 Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811203017.1A CN111054409B (en) 2018-10-16 2018-10-16 Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane

Publications (2)

Publication Number Publication Date
CN111054409A CN111054409A (en) 2020-04-24
CN111054409B true CN111054409B (en) 2022-12-13

Family

ID=70296574

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811203017.1A Active CN111054409B (en) 2018-10-16 2018-10-16 Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane

Country Status (1)

Country Link
CN (1) CN111054409B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114425325B (en) * 2020-09-28 2024-05-28 中国石油化工股份有限公司 Catalyst for preparing pyromellitic anhydride by oxidizing pyromellitic benzene and preparation method and application thereof
CN114797921B (en) * 2022-04-20 2023-08-08 润和催化剂股份有限公司 Maleic anhydride catalyst and preparation method and application thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000044494A1 (en) * 1999-01-29 2000-08-03 Scientific Design Company, Inc. Phosphorus/vanadium maleic anhydride catalyst preparation
CN101157048A (en) * 2007-11-20 2008-04-09 吐哈石油勘探开发指挥部石油天然气化工厂 A high performance vanadium phosphorus oxygen catalyst with nanostructure as well as its preparing method
CN104549392A (en) * 2013-10-22 2015-04-29 中国石油化工股份有限公司 Preparation method for vanadium-phosphorus oxide catalyst
CN105289743A (en) * 2015-11-20 2016-02-03 西安元创化工科技股份有限公司 Vanadium phosphorus oxide catalyst for producing maleic anhydride and preparation method for catalyst
CN106540728A (en) * 2016-10-13 2017-03-29 西安元创化工科技股份有限公司 A kind of activation method of used vpo catalyst when preparing cis-butenedioic anhydride by n butane oxidation
CN106749125A (en) * 2015-11-21 2017-05-31 中国石油化工股份有限公司 A kind of method that n butane oxidation prepares cis-butenedioic anhydride

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000044494A1 (en) * 1999-01-29 2000-08-03 Scientific Design Company, Inc. Phosphorus/vanadium maleic anhydride catalyst preparation
CN101157048A (en) * 2007-11-20 2008-04-09 吐哈石油勘探开发指挥部石油天然气化工厂 A high performance vanadium phosphorus oxygen catalyst with nanostructure as well as its preparing method
CN104549392A (en) * 2013-10-22 2015-04-29 中国石油化工股份有限公司 Preparation method for vanadium-phosphorus oxide catalyst
CN105289743A (en) * 2015-11-20 2016-02-03 西安元创化工科技股份有限公司 Vanadium phosphorus oxide catalyst for producing maleic anhydride and preparation method for catalyst
CN106749125A (en) * 2015-11-21 2017-05-31 中国石油化工股份有限公司 A kind of method that n butane oxidation prepares cis-butenedioic anhydride
CN106540728A (en) * 2016-10-13 2017-03-29 西安元创化工科技股份有限公司 A kind of activation method of used vpo catalyst when preparing cis-butenedioic anhydride by n butane oxidation

Also Published As

Publication number Publication date
CN111054409A (en) 2020-04-24

Similar Documents

Publication Publication Date Title
CN111054409B (en) Activation method of catalyst for preparing maleic anhydride by oxidizing n-butane
CN106607034B (en) A kind of method of loaded catalyst and its preparation method and application and methane dry reforming preparing synthetic gas
CN113117712B (en) Methane dry reforming reaction under microwave condition and catalyst thereof
US20130165671A1 (en) Oxidation catalyst for maleic anhydride production
TW201219113A (en) Improved VPO catalyst with low vanadium oxidation state for maleic anhydride production
CN112442001B (en) Method for preparing maleic anhydride by oxidizing n-butane
CN110449147B (en) Catalyst for phosgene synthesis and preparation method and application thereof
JP5388897B2 (en) Catalyst for producing unsaturated aldehyde and / or unsaturated carboxylic acid, and method for producing unsaturated aldehyde and / or unsaturated carboxylic acid using the catalyst
CN114408970B (en) Preparation method of hollow mesoporous carbon-doped gallium trioxide nanospheres and product thereof
JP6353553B2 (en) Catalyst arrangement with optimized surface area for the production of phthalic anhydride
CN113877560A (en) Synthesis method of methyl acrylate and solid base catalyst thereof
CN105801394A (en) Method for preparing methyl acraldehyde from tert-butyl alcohol
CN114308056B (en) Samarium-manganese-mullite-type nickel-based catalyst for autothermal reforming of acetic acid to produce hydrogen
CN104803820A (en) Method for producing isobutylene by catalyzing isobutane to dehydrogenate through carbon catalyst
JP5542557B2 (en) Catalyst for producing unsaturated aldehyde and unsaturated carboxylic acid, method for producing the same, and method for producing unsaturated aldehyde and unsaturated carboxylic acid
WO2009119416A1 (en) Catalyst for production of ethylene oxide, and process for production of ethylene oxide using the catalyst
CN114602458A (en) Mn (VO)3)2/V2O5Catalyst, preparation method and application thereof
KR102448519B1 (en) Method of conversion of sulfur trioxide and hydrogen production
CN107970935B (en) Mesoporous alumina catalyst, preparation method thereof and application of mesoporous alumina catalyst in preparation of 1, 3-butadiene through dehydrogenation of 1-butene by oxidation of carbon dioxide
CN112521281B (en) Synthesis method of methyl acrylate
WO2014024782A2 (en) Catalyst for production of acrylic acid from glycerin, and method for producing same
CN112090437A (en) Vanadium-phosphorus-oxygen catalyst for preparing maleic anhydride by n-butane oxidation and preparation method and application thereof
CN116764631A (en) Propane dehydrogenation catalyst, preparation method and application
Zhang et al. Hydrogenolysis of biomass‐derived levulinic acid to produce 1, 4‐pentanediol over Co/ZrO2 catalyst
CN114477298A (en) Composite oxide and preparation method and application thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant