阅读说明：本技术 附聚的odh催化剂 (Agglomerated ODH catalysts ) 是由 Y.金 V.西曼真科夫 高效良 D.沙利文 M.巴尼斯 R.安塞乌 Y.斯泰尔斯 于 2018-07-31 设计创作，主要内容包括：用于将低级链烷烃转化成烯烃(例如乙烷转化成乙烯)的氧化脱氢催化剂,在作为附聚物制备时,优选与选自TiO<Sub>2</Sub>、ZrO<Sub>2</Sub>、Al<Sub>2</Sub>O<Sub>3</Sub>、AlO(OH)及其混合物的浆的载体一起挤出,所述催化剂具有得到25%转化率时的较低温度。(For converting lower alkanes to olefins(e.g., ethane to ethylene) oxidative dehydrogenation catalysts, when prepared as agglomerates, are preferably admixed with a catalyst selected from the group consisting of TiO 2 、ZrO 2 、Al 2 O 3 AlO (OH), and mixtures thereof, having a lower temperature at which 25% conversion is obtained.)

1. An agglomerated catalyst, comprising:

10 to 95 wt% of a catalyst of the formula:

Mo_1.0V_{0.12 -0.49}Te_0.6-0.16Nb_0.15-0.20O_d

wherein d is a number satisfying the valence of the oxide; and

5 to 90 wt% of a binder selected from TiO₂、ZrO₂、Al₂O₃AlO (OH) and mixtures thereof, provided that ZrO is present₂Not in combination with an adhesive comprising aluminum.

2. The agglomerated catalyst of claim 1, the agglomerated catalyst having a BET determination of less than 35m²Cumulative surface area in g.

3. The agglomerated catalyst of claim 2, the agglomerated catalyst having a cumulative pore volume of from 0.05 to 0.50cm 3/g.

4. The agglomerated catalyst of claim 2, the agglomerated catalyst having a pore size distribution of less than 4% having a pore width dimension of less than 150 angstroms.

5. The agglomerated catalyst of claim 2, the agglomerated catalyst having a percent pore area distribution of less than 40% and a corresponding percent pore volume of less than 20%.

6. The agglomerated catalyst of claim 2, which is in the shape of a sphere, rod, ring, or saddle having a size of about 1.3mm to 5 mm.

7. The agglomerated catalyst of claim 6, wherein the binder is an acidified binder.

8. The agglomerated catalyst of claim 6, wherein the binder is a base-treated binder.

9. The agglomerated catalyst of claim 7, wherein the binder is selected from the group consisting of TiO₂、Al₂O₃、ZrO₂AlO (OH) and mixtures thereof, with the proviso that ZrO₂Not mixed with the aluminium-based binder.

10. The agglomerated catalyst of claim 8, wherein the binder is selected from the group consisting of TiO₂、Al₂O₃、ZrO₂AlO (OH) and mixtures thereof, with the proviso that ZrO₂Not mixed with the aluminium-based binder.

11. The agglomerated catalyst of claim 9, which is in the shape of a rod, has an aspect ratio of from 1 to 5/1.3, and has a crush strength of up to 100N/mm.

12. The agglomerated catalyst of claim 10, which is in the shape of a rod, has an aspect ratio of from 1 to 5/1.3, and has a crush strength of up to 100N/mm.

13. The agglomerated catalyst of claim 9, which is in the shape of a sphere having a crush strength of up to 100N.

14. The agglomerated catalyst of claim 10, which is in the shape of a sphere having a crush strength of up to 100N.

15. The agglomerated catalyst of claim 6, wherein the catalyst has the empirical formula:

Mo_1.0V_0.25-038Te_0.10-0.16Nb_0.15-0.19O_d

wherein d is a number satisfying the valence of the oxide.

16. The agglomerated catalyst of claim 6, wherein the catalyst has an empirical formula determined by PIXE:

Mo_1.0V_0.22-033Te_0.10-0.16Nb_0.15-0.19O_d

wherein d is a number satisfying the valence of the oxide.

17. The agglomerated catalyst of claim 6, wherein the catalyst has an empirical formula determined by PIXE:

Mo_1.0V_0.12-0.19Te_0.14-0.16Nb_0.15O_d

wherein d is a number satisfying the valence of the oxide.

18. The agglomerated catalyst of claim 6, having an empirical formula determined by PIXE:

Mo_1.0V_0.17-0.20Te_0.06-0.07Nb_0.19-0.20O_d

wherein d is a number satisfying the valence of the oxide.

19. The agglomerated catalyst of claim 6, having an empirical formula determined by PIXE:

Mo_1.0V_0.12-0.19Te_0.14-0.16Nb_0.15O_d

wherein d is a number satisfying the valence of the oxide.

20. A method of preparing the catalyst of claim 1, comprising:

i) forming an aqueous catalyst slurry or paste comprising up to 10 to 95 (check) wt% catalyst;

ii) adding up to 5 to 90% by weight of TiO selected from the group consisting of TiO to the slurry or paste₂、ZrO₂And Al₂O₃AlO (OH) and mixtures thereof in the form of an acidic, neutral or basic colloidal suspension having a pH of at most 12, with the proviso that ZrO is present₂Not used in combination with an aluminum-based binder;

iii) if desired, reducing the water content of the resulting slurry or paste to less than 30% by weight;

iv) extruding the reduced water slurry or paste to form a rod, ring or saddle having a size of about 1.3mm to 5 mm;

v) drying the particles at a temperature of from 90 ℃ to 115 ℃ in an oxygen-containing atmosphere; and

vi) calcining the resulting particles at a temperature of up to 600 ℃.

21. The process of claim 20 wherein in step vi) the particles are re-calcined at a temperature of less than 350 ℃.

22. The method of claim 20, further comprising spheroidizing the rod-shaped agglomerated particles at a temperature of up to 300 ℃, the resulting spheres then being further calcined at a temperature of up to 600 ℃.

23. A composition for the treatment of a mammal comprising oxygen and one or more C_2-4A process for the oxidative dehydrogenation of a mixture of alkanes, the process comprising subjecting the mixture to 500hr at a temperature of 340 ℃ to less than 420 ℃, a pressure of 172.3kPag (25psig) to 689kPag (100psig)^-1To 3000hr^-1And a residence time of from 0.002 to 20 seconds through the extruded agglomerated catalyst of claim 1.

24. The process of claim 23, comprising increasing the amount of binder in the extruded catalyst in the range of 5 to 50 wt% binder in the catalyst and increasing the gas flow rate through the catalyst bed by a proportional amount while maintaining a bed temperature of less than 420 ℃, preferably less than 395 ℃, preferably less than 285 ℃, and maintaining selectivity within ± 3%.

Technical Field

The present invention relates to the conversion of paraffins (usually C)_2-4Preferably ethane) to the corresponding olefin. Such reactions can be carried out in fixed bed or fluidized bed reactors. It is desirable to form catalyst particles with sufficient strength to avoid attrition during use. By selecting a suitable binder for the catalyst particles, the activity of the catalyst can be improved in terms of temperature to achieve 25% conversion without significant (e.g., less than 5%) reduction in selectivity.

Background

U.S. patent 4,524,236 assigned to Union Carbide Corporation, granted to McCain at 18.6.1985, teaches a catalyst for the oxidative dehydrogenation of ethane to ethylene comprising Mo_aV_bNb_cSb_dX_eThe calcined composition of (a), wherein:

x = at least one of L i, Sc, Na, Be, Mg, Ca, Sr, Ba, Ti, Zr, Hf, Y, Ta, Cr, Fe, Co, Ni, Ce, L a, Zn, Cd, Hg, Al, Tl, Pb, As, Bi, Te, U and W, and

a =0.5 to 0.9

b =0.1 to 0.4

c =0.001 to 0.2

d =0.001 to 0.1

e =0.001 to 1.0

a. The values of b, c, d and e constitute the relative number of gram atoms of the elements Mo, V, Nb, Sb and X in the catalyst, respectively. These elements are present in combination with oxygen in the form of various oxides.

The patent teaches that the catalyst may be used with or without a support. The catalyst is prepared as a solution, dried and calcined. The patent teaches that suitable supports for the catalyst include silica, alumina, silicon carbide, zirconia, titania and mixtures thereof. When used on a support, the supported catalyst typically comprises from about 10% to 50% by weight of the catalyst composition, with the remainder being the support. The patent teaches impregnation of the support with a catalyst (column 4, lines 38 to 43).

European patent application 0262264 (corresponding to CA 1262556), published on 30.3.1988 and assigned to Union Carbide Corporation in the name of Manyik et al, teaches a process for the dehydrogenation of ethane to ethylene using the catalyst of U.S. patent 4,524,236 issued to McCain on 18.6.1985. This patent application teaches impregnation (i.e., incipient wetness method) of a support with a catalyst solution (page 7, lines 30-35). The support has a surface area of less than about 1 square meter per gram and a relatively large median pore diameter of greater than 10 microns. The patent does not teach agglomerated catalysts. Incipient wetness impregnation requires a solution of dissolved catalyst with a controlled type (improved adsorption into pores) and volume of solvent to minimally wet the support. The pore size, composition of the support (hydrophobic or hydrophilic), and type and amount of solvent limit the absorption and placement of the active catalyst within the supported catalyst. The agglomeration process is carried out by blending a dispersion of binder and carrier, and optionally reducing the solvent/diluent, extrusion and final drying. The agglomeration process provides a wider window for binder to catalyst ratio and also improves control of pore volume, size and distribution.

U.S. Pat. No. 7,319,179, assigned to Conseio Superior inventigilance catalysts and Universal polar De Valencia, to L opez Nieto et al, 1/15.2008, teaches a five-component metal oxide catalyst for the oxidative dehydrogenation of ethane which teaches that the catalyst can be a mixed oxide supported on a solid such as silica, alumina, titania and mixtures thereof in a preferred manner, silica as a solid support is present in a proportion of 20 to 70% by weight relative to the total weight of the catalyst.

U.S. patent application 20140121433, assigned to Siluria, published on 5/1 2014 in the name of Cizeron et al, teaches a catalyst for the oxidative coupling of methane. The terms binder and diluent appear to be used interchangeably in this disclosure. The oxidative coupling catalyst for methane (OCM) is a nanowire. The patent also teaches catalysts [357 and 358] that can be used for the oxidative dehydrogenation of ethane. "diluents" are discussed in paragraphs [0146 to 0153 ]. These appear to be inert. In any case, the present invention does not consider nanowire composites.

U.S. patent 8,846,996 assigned to NOVA Chemicals (International) s.a. issued 9/30 in 2014 in the name of Kustov et al teaches the co-mulling (wet or dry milling, column 5, line 50) of an oxidative dehydrogenation catalyst equivalent to the present invention with an inert support selected from oxides of titanium, zirconium, aluminum, magnesium, yttrium, lanthanum, silicon and mixed compositions thereof or carbon matrices to produce particles of 1 to 100 microns in size and to shape the resulting particles into 0.1 to 2mm size pellets. The present invention eliminates the co-milling step. In addition, the product of the co-grinding step is shaped into pellets and crushed to obtain the appropriate particle size (column 5, line 55).

U.S. patent application 20170008821, assigned to King Fahd University of petroleum and Minerals, published in 2017 on 12.1.7, teaches an oxidative dehydrogenation process conducted in a circulating stirred bed reactor in the absence of gaseous oxygen. The catalyst comprises lattice oxygen. When oxygen is depleted from the catalyst, it is recycled to the oxidation reactor where it is replenished with lattice oxygen. The catalyst is supported on an alumina-based support which has been used for incipient wetness ZrO₂Processing (paragraph 64). The catalyst is then supported on the treated support also in an incipient wetness process. The catalyst was prepared without extrusion.

The present invention seeks to provide an (extruded) agglomerated catalyst for the oxidative dehydrogenation of ethane that can be extruded into various shapes with improved activity. Extruding the catalyst into a mixture selected from TiO₂、ZrO₂、Al₂O₃AlO (OH) and mixtures thereof on an acid support with the proviso that ZrO₂Not with adhesives containing aluminum.

Summary of The Invention

The present invention provides an agglomerated, preferably extruded, catalyst comprising:

from 10 to 95, preferably from 25 to 80, ideally from 30 to 45 wt% of a catalyst of the formula:

Mo_1.0V_{0.12 -0.49}Te_0.6-0.16Nb_0.15-0.20O_dwherein d is a number satisfying the valence of the oxide; and

5 to 90, preferably 20 to 75, ideally 55 to 70% by weight of a binder selected from TiO₂、ZrO₂、Al₂O₃AlO (OH) and mixtures thereof, provided that ZrO is present₂Not in combination with an adhesive comprising aluminum.

In another embodiment, the agglomerated catalyst has a particle size of less than 35m as determined by BET²Cumulative surface area per gram, or less than 20m²A,/g, or less than 3m²/g。

In another embodimentIn which the agglomerated catalyst has a cumulative pore volume of from 0.05 to 0.50cm³/g。

In another embodiment, the agglomerated catalyst has a pore size distribution such that less than 4% of the pores have a pore width dimension of less than 150 angstroms.

In another embodiment, the agglomerated catalyst has a percent pore area distribution of less than 40% and a corresponding percent pore volume of less than 20%.

In another embodiment, the agglomerated catalyst has the shape of a sphere, rod, ring, or saddle of about 1.3mm to 5mm size.

In another embodiment, the adhesive is an acidified adhesive.

In another embodiment, the binder is an alkali treated binder.

In another embodiment, the binder is selected from TiO₂、Al₂O₃、ZrO₂AlO (OH) and mixtures thereof, with the proviso that ZrO₂Not mixed with the aluminium-based binder.

In another embodiment, the agglomerated catalyst is in the shape of a rod, having an aspect ratio of 1 to 5/1.3, and having a crush strength of up to 100N/mm.

In another embodiment, the agglomerated catalyst is in the shape of spheres, having a crush strength of up to 100N.

In another embodiment of the agglomerated catalyst, the catalyst has the empirical formula:

Mo_1.0V_0.25-038Te_0.10-0.16Nb_0.15-0.19O_d

wherein d is a number satisfying the valence of the oxide.

In another embodiment of the agglomerated catalyst, the catalyst has an empirical formula of Mo as determined by PIXE_1.0V_0.22-033Te_0.10-0.16Nb_0.15-0.19O_d

Wherein d is a number satisfying the valence of the oxide.

In another embodiment of the agglomerated catalyst, the catalyst has an empirical formula determined by PIXE:

Mo_1.0V_0.12-0.19Te_0.14-0.16Nb_0.15O_d

wherein d is a number satisfying the valence of the oxide.

In another embodiment of the agglomerated catalyst, the catalyst has an empirical formula determined by PIXE:

Mo_1.0V_0.17-0.20Te_0.06-0.07Nb_0.19-0.20O_d

wherein d is a number satisfying the valence of the oxide.

In another embodiment of the agglomerated catalyst, the catalyst has an empirical formula determined by PIXE:

Mo_1.0V_0.12-0.19Te_0.14-0.16Nb_0.15O_d

wherein d is a number satisfying the valence of the oxide.

In another embodiment, the present invention provides a method of preparing the above catalyst, the method comprising:

i) forming an aqueous catalyst slurry or paste comprising up to 10 to 95 wt% catalyst;

ii) adding to the slurry or paste up to 5 to 90% by weight of TiO selected from the group consisting of₂、ZrO₂And Al₂O₃AlO (OH) and mixtures thereof, in the form of an acidic, neutral or basic colloidal suspension having a pH of at most 12, usually 1 to 12, with the proviso that ZrO is present₂Not used in combination with an aluminum-based binder;

iii) if desired, reducing the water content of the resulting slurry or paste to less than 30% by weight;

iv) extruding the reduced water slurry or paste to form a rod, ring or saddle having a size of about 1.3mm to 5 mm;

v) drying the particles at a temperature of from 90 ℃ to 115 ℃ in an oxygen-containing atmosphere; and

vi) calcining the resulting particles at a temperature of up to 600 ℃.

In another embodiment of step vi), the particles are re-calcined at a temperature of less than 350 ℃.

In another embodiment, the rod-shaped agglomerated particles are spheroidized at a temperature of up to 300 ℃, and the resulting spheres are then further calcined at a temperature of up to 600 ℃.

The invention further provides a process for the preparation of a composition comprising oxygen and one or more C' s_2-4A process for the oxidative dehydrogenation of a mixture of alkanes, the process comprising subjecting the mixture to 500hr at a temperature of 340 ℃ to less than 420 ℃, a pressure of 172.3kPag (25psig) to 689kPag (100psig)^-1To 3000hr^-1And a residence time of from 0.002 to 20 seconds through the extruded agglomerated catalyst of claim 1.

In another embodiment, the oxidative dehydrogenation process comprises increasing the amount of binder in the extruded catalyst in the range of 5 to 50 wt% binder in the catalyst and increasing the gas flow rate through the catalyst bed by a proportional amount while maintaining a bed temperature of less than 420 ℃, preferably less than 395 ℃, preferably less than 385 ℃, and maintaining the selectivity within ± 3%.

Brief Description of Drawings

Figure 1 is a plot of the percent pore area of the binderless catalyst as a function of pore width (sample 13) as determined by BET (pore width distribution in terms of percent pore area).

Figure 2 is a plot of the percent pore area of the catalyst with TiO2 binder as a function of pore width (sample 5) as determined by BET (pore width distribution in terms of percent pore area).

FIG. 3 is a plot of the percent pore area of an extruded catalyst with TiO2 binder as a function of pore width as determined by BET (sample 25).

Figure 4 is a plot of the percent pore area of unextruded catalyst having 60% alo (oh) binder (pore width distribution in terms of percent pore area) as a function of pore width as determined by BET (sample 14).

FIG. 5 shows a graph with 60% Al₂O₃The percent pore area of the binder without extruded catalyst is plotted as a function of pore width (sample 19) as determined by BET (pore width distribution in percent pore area).

Description of the embodiments

Other than in the operating examples, or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

It should also be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10, i.e., having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the numerical ranges disclosed are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this specification are approximations.

All compositional ranges expressed herein are in practice limited to and do not exceed 100% (volume percent or weight percent) in total. Where multiple components may be present in the composition, the sum of the maximum amounts of each component may exceed 100%, and it is understood, and as will be readily appreciated by those skilled in the art, that the amounts of the components actually used should correspond to a maximum of 100%.

The binder means a material added to the catalyst t to increase the cohesive force between catalyst particles and optionally improve the adhesive force between the catalyst and the support (if present).

In the specification, the phrase "temperature at 25% conversion of ethane to ethylene" is determined by: the temperature at which there is 25% conversion of ethane to ethylene is determined by plotting the conversion to ethylene against temperature (typically with data points below and above 25% conversion) or fitting the data to a formula. In some cases, in the examples, the data must be extrapolated to determine the temperature at which 25% conversion occurs.

In the specification, the phrase "selectivity at 25% conversion" is determined by plotting the selectivity as a function of temperature, or fitting to a formula. Then, where the temperature at which 25% conversion occurs has been calculated, the selectivity at that temperature can be determined from a graph or from a formula.

There are a number of methods for correlating surface area to volume of gas that can be incorporated into the agglomerated carrier.

One method is cumulative pore volume (cm)³Per g) and cumulative surface area (m)²/g)。

The second method is the pore width distribution versus surface area percentage (e.g., what surface area of the catalyst has a pore size of a certain diameter). In fig. 4, 4% of the aperture area has an aperture width (diameter) range of 5-150A. The remaining 96% of the pore area has a pore width (diameter) greater than 150A.

The third method comprises the following steps:

first determining the cumulative surface area as a function of cumulative pore volume;

second, the cumulative surface area and cumulative pore volume are normalized to yield a percentage of the total distribution; and

third, the percent surface area is plotted as a function of percent pore volume.

For low (C)_2-4) Oxidative dehydrogenation of alkanes (e.g., ethane) results in treated and product molecules having diameters of about 2.5-4 angstroms (0.25-0.40 nm). The molecular diameter, pore size and pore surface area affect the probability of the molecule interacting with the catalyst (on the pore walls or surfaces). For example, large diameter pores, low internal surface area and large pore volume will have the lowest potential for molecular contact with the internal surface of the material (catalyst), thereby leading toResulting in lower conversion.

Useful for lower alkanes (e.g. C)_2-4Alkane, especially ethane) oxydehydrogenation to C_2-4One catalyst family of olefins, particularly ethylene, is that of mixed oxides of molybdenum, vanadium, tellurium, niobium and optionally other components for the oxidative dehydrogenation of ethane to ethylene, such as Pt, Pd, Ta, Ti, W, Hf, Zr, Sb Zn, Sc, Y, L a, Ce, Ta, Cr, W, U, Te, Fe, Co and Ni.

Can be used for alkane (especially lower C)_2-4Alkane) oxidative dehydrogenation has the formula:

Mo_1.0V_{0.12 -0.38}Te_0.6-0.16Nb_0.11-0.20O_d

wherein d is a number satisfying the valence of the oxide.

The composition of the catalyst may vary within the above formula depending on how the catalyst is prepared.

Thus, such catalysts and their precursors are generally prepared by hydrothermal processes.

Typically, in a hydrothermal process, the precursor is prepared by:

i) forming an aqueous solution of ammonium heptamolybdate (tetrahydrate) and telluric acid at a temperature of 30 ℃ to 85 ℃ and adjusting the pH of the solution to 6.5 to 8.5, preferably 7 to 8, most preferably 7.3 to 7.7, with a nitrogenous base to produce a soluble salt of the metal;

ii) preparing an aqueous solution of vanadyl sulfate at a temperature of from room temperature to 80 ℃ (preferably from 50 ℃ to 70 ℃, most preferably from 55 ℃ to 65 ℃);

iii) mixing together the solutions from steps i) and ii);

iv) preparation of niobium monoxide (NbO (C) oxalate₂O₄H)₃) Is slowly (dropwise) added to the solution of step iii) to form a slurry; and is

v) heating the resulting slurry in an autoclave under an inert atmosphere at a temperature of 150 ℃ to 190 ℃ for not less than 6 hours.

The resulting solid from step v) is filtered, washed with deionized water, and the washed solid is dried at a temperature of 70 to 100 ℃ for a period of 4 to 10 hours.

In another embodiment, the precursor is calcined in an inert atmosphere at a temperature of 200 ℃ to 600 ℃ for 1 to 20 hours.

The above is a typical hydrothermal process for preparing the precursor and the final oxidative dehydrogenation catalyst.

If the catalyst is prepared by conventional hydrothermal methods, the catalyst may have the formula:

Mo_1.0V_0.25-0.45Te_0.10-0.16Nb_0.15-0.19O_d

wherein d is a number satisfying the valence of the oxide.

In some preparation methods the dried catalyst precursor is treated with a peroxide, usually hydrogen peroxide. The hydrogen peroxide treatment can be carried out at atmospheric pressure and at room temperature (e.g., 15 ℃ to 30 ℃) to about 80 ℃, in some cases 35 ℃ to 75 ℃, and in other cases 40 ℃ to 65 ℃. The concentration of hydrogen peroxide in water may be from 10 to 30 wt%, in some cases from 15 to 25 wt%. The treatment time may be 1 to 10 hours, in some cases 2 to 8 hours, in other cases 4 to 6 hours. With 0.3-2.8ml (in some embodiments 0.3-2.5ml) of 30 wt.% H per gram of precursor₂O₂The equivalent weight of the aqueous solution treats the catalyst precursor. The treatment should be in a slurry (e.g., at least partially suspending the precursor) to provide uniform H₂O₂Distributing and controlling the temperature rise. For with H₂O₂Post-calcination treatment of (2) with H₂O₂There is a sudden delay in the violent reaction. This results in a more controlled and safe transient response.

The treated catalyst precursor is then subjected to calcination to produce an active oxidative dehydrogenation catalyst. The treated precursor can be calcined in an inert atmosphere at a temperature of 200 ℃ to 600 ℃ for a time period of 1 to 20 hours. The purge gas used for calcination is an inert gas comprising nitrogen, helium, argon, CO₂(preferred is>90% high purity) comprising less than 1% by volume of hydrogen or air at 200-. The calcination step may take from 1 to 20 hours, in some cases from 5 to 15, in other cases from about 8 to 12 hours, typically about 10 hours. The resulting mixed oxide catalyst is generally water insolubleIs a brittle solid. Typically, the calcined product has a bulk density of 1.20 to 1.90 g/cc. The bulk density is based on the weight of 1.5ml of extruded and crushed catalyst.

When treated with peroxide, the catalyst may have the formula as determined by PIXE:

Mo_1.0V_0.22-033Te_0.10-0.16Nb_0.15-0.19O_d

wherein d is a number satisfying the valence of the oxide.

In some methods, the hydrothermal treatment may be performed at a controlled low pressure of 10psi to 190psi (960kPa to 1300 kPa). This can be achieved by having a vent to the autoclave and some suitable pressure control means (e.g. a regulator) or in some cases a column of liquid (e.g. water) through which the vent gas must escape. In such a process, the duration of the hydrothermal treatment can be extended up to 72 hours.

When prepared by this method, the catalyst may have the formula:

Mo_1.0V_0.32-049Te_0.10-0.17Nb_0.14-0.17O_d

wherein d is a number satisfying the valence of the oxide.

In some processes, the pressure in the hydrothermal reactor can be reduced even further to a pressure in the range of 1 to 8psig (6.89kPag to 55.1kPag), preferably less than 5psig (34.4kPag), above atmospheric pressure. Under these conditions, the catalyst may have an empirical formula determined by PIXE:

Mo_1.0V_0.12-0.19Te_0.14-0.16Nb_0.15O_d

wherein d is a number satisfying the valence of the oxide.

The present invention encompasses the use of mixtures or combinations of the above materials.

According to the invention, from 10 to 95% by weight, preferably from 25 to 80% by weight, ideally from 30 to 45% by weight, of the catalyst is agglomerated (extruded) together with from 5 to 90% by weight, preferably from 20 to 75% by weight, ideally from 55 to 70% by weight, of one or more binders selected from the group consisting of acidic TiO₂、ZrO₂、Al₂O₃AlO (OH) and mixtures thereof, with the proviso that ZrO₂Not mixed with an aluminum compound.

The agglomerated catalyst may be prepared by methods known to those skilled in the art. In one embodiment, the calcined catalyst is suspended in a diluent, typically water, and an acidic, neutral or basic suspension of the prepared or purchased binder is added to the catalyst suspension in the amounts described above.

The binder may be selected from TiO₂、ZrO₂、Al₂O₃And AlO (OH) and mixtures thereof. In some embodiments, ZrO₂Not mixed with the aluminium-based binder.

The binders are commercially available or prepared as acidic, neutral or alkaline pastes, slurries or suspensions containing from about 3 to 90 weight percent binder, in some embodiments from 20 to 80 weight percent binder, typically from about 40 to 60 weight percent binder. The balance of the binder is a volatile diluent, typically water. Other additives may be present in the binder solution for improving binder adhesion to the active phase. The paste, slurry, or suspension of the binder may have a pH of about 0.5 to 12, in some embodiments 3 to 6. The paste, slurry or suspension of the binder may be acidified with a conventional acid selected from the group consisting of hydrochloric, hydrobromic, hydroiodic, perchloric, sulfuric, nitric and organic acids, and mixtures thereof. The alkaline paste, slurry or suspension of the binder may be treated with a common base, preferably a volatile base, such as a lower di-C_1-6Alkyl amines, pH from 7.5 to 12, in some embodiments from 8 to 10.

A slurry of a binder is added to a slurry of a catalyst to form a paste, slurry or slurry (hereinafter referred to as mud). The mud is prepared without co-mulling the catalyst and binder. The diluent is typically separated from the suspension portion by drying, but other means such as filtration or application of vacuum may also be suitable. The diluent (water) content of the resulting mud is typically reduced to less than 30 wt%, preferably less than 25 wt%, and in some embodiments less than 20 wt%. Typically, the blend is heated at a temperature of about 90 to 100 ℃ at atmospheric pressure. As mentioned above, in some cases, a vacuum may be applied, thereby lowering the temperature accordingly to remove the diluent. It is important that the partially dried mixture be sufficiently fluid that it can flow through the extruder under normal operating conditions.

In order to improve the flow properties of the mixture or slurry, it may be desirable to include one or more flow improvers and/or extrusion aids in the mixture prior to extrusion. Suitable additives to be included in the mixture include cellulose or derivatives thereof, fatty amines, quaternary ammonium compounds, polyvinylpyridines, polyvinyl alcohols, sulfoxonium, sulfonium, phosphonium and iodonium compounds, alkylated aromatic compounds, acyclic monocarboxylic acids, fatty acids, sulfonated aromatic compounds, alcohol sulfates, ether alcohol sulfates, sulfated greases, phosphonates, polyoxyethylene alkylphenols, polyoxyethylene alcohols, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyacrylamides, polyols and acetylenic diols. Some additives are sold under the trademarks Nalco and Superfloc.

The compaction pressure in the extruder was adjusted to produce a structure having an average (side) crush strength of up to 100N (22.5 lb).

The resulting product (mud) has the consistency of a paste or thick paste (e.g., mud). The paste is extruded through a cutter to form a shaped product such as a sphere, rod (including trilobe rods), ring or saddle, and then dried. The particles (typically rod-shaped) may be spheronized to produce spheres up to about 5mm (typically about 2 to 3mm) in diameter.

Growth agglomeration (stirring method)

The extruded particles may agglomerate with each other in the fluid flow system. This is usually done in the presence of a liquid and a binder. Particle size increase occurs by coalescence or aggregation based on capillary forces (snowballing). In several exceptional cases, the primary cohesive force is van der waals. Typically, the agglomerates are spherical and have a diameter between 0.5 and 20 mm. Typical equipment types include drums, cones, pans, paddle mixers and plowshare mixers.

The extruded/agglomerated product may have a diameter of about 0.5 to 5mm, typically 1.3 to 2.5mm, ideally 1.35 to 1.45mm, and a length of up to 8mm, typically less than 5 mm. The aspect ratio of the particles may be 1 (e.g., spheres) to 5/1.3.

Many variations occur as the slurry passes through the extruder. The extruder may help reduce the level of diluent (e.g., water) in the product. Depending on the pressure in the extruder, it will collapse some of the interstitial voids within the slurry. Thus, the surface area of the extruded and dried particles may be less than 35m as determined by BET²/g, or less than 20m²A/g, or less than 3.0m²(ii) in terms of/g. At high loadings of binder greater than 20 wt%, the surface area of the agglomerated catalyst may increase, in some embodiments, up to about 250m at high loadings of binder (e.g., 60 wt%)²/g。

Thus, the agglomerated and dried particles may have a pore volume range of about 0.05 to 0.50cm 3/g. The resulting shaped product is then dried in air at a temperature of from about 80 ℃ to about 150 ℃, typically less than 120 ℃, in some embodiments less than 110 ℃. The dried particulate catalyst is then calcined at a temperature of from 300 ℃ to 600 ℃, in some embodiments from 350 ℃ to 500 ℃. The agglomerated catalyst is calcined for a period of not less than 1 hour, usually up to about 4 hours.

The crush strength of the final particles should be sufficient to withstand the operating conditions in the ODH reactor. The crush strength can range up to 100N/mm, in some embodiments 10N/mm (2.25lb) or less (e.g., for rods). The resulting agglomerated catalyst may have a pore size distribution of less than 4% having a pore width dimension of less than 150 angstroms. Alternatively, the resulting agglomerated catalyst may have a cumulative pore volume of 0.05 to 0.50cm 3/g.

Oxidative dehydrogenation reaction

Typically, Oxidative Dehydrogenation (ODH) processes involve passing a mixed feed of ethane and oxygen at a temperature of less than 420 ℃, in some cases less than 410 ℃, in some cases less than 400 ℃, in some cases less than 390 ℃, and in some cases less than 380 ℃. The catalyst of the invention can be used at temperature(s) of not less than, desirably not less than 1500hr^-1(preferably at least 3000 hr)^-1) Is passed through the fixed bed or beds at a pressure of from 0.8 to 1.2 atmospheres. In some casesIn embodiments, the catalyst of the present invention allows for an oxidative dehydrogenation reactor at 500hr^-1To 3000hr^-1The space velocity of (a) is operated at a temperature generally from 300 ℃ to 450 ℃, in some cases from 330 ℃ to 380 ℃, and in some embodiments from 340 ℃ to 360 ℃.

The outlet pressure from the ODH reactor can be 105kPa (15psi) to 172.3kPa (25psi), while the inlet pressure can be higher than the pressure drop across the bed, depending on a number of factors, including reactor configuration, particle size in the bed, and space velocity. Typically, the pressure drop may be less than 689kPa (100psi), preferably less than 206.7kPa (30 psi).

One or more alkanes (usually C) in the reactor_2-4Alkane) is 0.002 to 20 seconds.

The feed to the oxidative dehydrogenation reactor includes oxygen in excess of the upper explosive/combustion limit. For example, for oxidative dehydrogenation of ethane, the oxygen is generally present in an amount of not less than about 16 mole percent, preferably about 18 mole percent, e.g., about 22 to 27 mole percent, or 23 to 26 mole percent, in the feed stream comprising primarily oxygen and ethane. Too high an excess of oxygen is undesirable as it may result in reduced selectivity from combustion of the feed or the final product. In addition, too high an excess of oxygen in the feed stream may require an additional separation step at the downstream end of the reaction. In some cases, feed gases with low reactivity such as nitrogen, argon, helium, CO may be used₂CO, steam to dilute the feed stream.

In some embodiments, the percentage of alkane may be up to 40 mole%. For the case where the gas mixture prior to ODH contains 25 mol% oxygen and 40 mol% alkanes, the balance must be made up with an inert diluent (e.g., nitrogen, carbon dioxide or steam). The inert diluent should be present in the gaseous state under the conditions within the reactor and should not increase the flammability of the hydrocarbon added to the reactor, a characteristic that the skilled person would understand when deciding which inert diluent to use.

The goal is 100% conversion of alkanes while leaving minimal unreacted alkanes and oxygen out of the ODH reactor and producing minimal carbon monoxide or carbon dioxide. In one embodiment of the invention, the product stream exiting the ODH reactor comprises less than 5% unreacted lower alkanes, preferably less than 2.5%, most preferably less than 1%. In another embodiment of the invention, the product stream exiting the ODH reactor comprises less than 2% oxygen, preferably less than 1.5% oxygen, and most preferably less than 1% oxygen.

In another embodiment of the invention in the oxidative dehydrogenation process, the amount of binder in the extruded catalyst is increased in the range of 5 to 50 weight percent and the gas flow rate through the catalyst bed is increased by a proportional amount (e.g., 10 percent increase in binder amount, up to 10 percent increase in gas flow rate) while maintaining a bed temperature of less than 420 ℃, preferably less than 395 ℃, preferably less than 285 ℃, and maintaining a selectivity within ± 3.

This improves the economics of the reaction, similar to increasing productivity.

The invention will now be illustrated by the following non-limiting examples.