Method and system for forming plug and play oxide catalysts

Abstract

An oxide catalyst is formed by vaporizing a quantity of at least one precursor material or catalyst material thereby forming a vapor cloud. The vapor cloud is quenched forming precipitate nanoparticles. The nanoparticles are impregnated onto supports. The supports are able to be used in existing heterogeneous catalysis systems. A system for forming oxide catalysts comprises means for vaporizing a quantity of at least one precursor material or at least one catalyst material, quenching the resulting vapor cloud and forming precipitate nanoparticles. The system further comprises means for supports with the nanoparticles.

Claims

1. A supported catalyst, comprising: a. support structures, wherein the support structure comprises a porous oxide; and b. nanoparticles bonded to the support structures, wherein the nanoparticles comprise an oxide catalyst; wherein the nanoparticles are attached to the support structures by an oxide-oxide bond.

2. The supported catalyst of claim 1, wherein the oxide catalyst comprises a metal oxide.

3. The supported catalyst of claim 2, wherein the oxide catalyst comprises lanthanum iron oxide.

4. The supported catalyst of claim 1, wherein the nanoparticles are prepared using plasma.

5. The supported catalyst of claim 1, wherein the support structures are macroscopic particles.

6. The supported catalyst of claim 1, wherein the nanoparticles are about 0.5 nanometers to about 200 nanometers in diameter.

7. The supported catalyst of claim 1, wherein the nanoparticles are on the surface and in the pores of the support structures.

8. The supported catalyst of claim 7, wherein the nanoparticles are deposited on the surface and in the pores of the support structures by suspending the nanoparticles in a solution to form a suspension, and mixing the suspension with the support structures.

9. The supported catalyst of claim 8, wherein the solution further comprises a dispersant.

10. The supported catalyst of claim 8, wherein the suspension of nanoparticles mixed with the support structures is dried, then exposed to heat, pressure, or a combination of heat and pressure to calcine the nanoparticles onto the support structures.

11. The supported catalyst of claim 7, wherein the nanoparticles are deposited on the surface and in the pores of the support structures by suspending the nanoparticles in a solution to form a suspension, and mixing the suspension with a slurry having the support structures suspended therein.

12. The supported catalyst of claim 11, wherein the solution further comprises a dispersant.

13. The supported catalyst of claim 1, wherein the nanoparticles comprise a metal oxide formed from a precursor material, wherein the precursor material is selected from the group consisting of a metal, a metal oxide, a metal salt, a carbon compound, a chlorine compound, a phosphorous compound, and any combination thereof.

14. The supported catalyst of claim 1, wherein the oxide-oxide bond is formed by calcination.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is better understood by reading the following detailed description of an exemplary embodiment in conjunction with the accompanying drawings.

(2) FIG. 1 prior art illustrates an existing process for forming a useful support for use in heterogenous catalysis.

(3) FIG. 2 prior art shows a porous support generally used as a support in heterogeneous catalysis.

(4) FIG. 3 shows the preferred embodiment of a novel process for forming a support for use in heterogeneous catalysis.

(5) FIG. 4A shows an example of a nanoparticle formed as part of the process of FIG. 3.

(6) FIG. 4B shows a close up of an impregnated porous support.

(7) FIG. 4C shows a close up of an impregnated macro support.

(8) FIG. 5 shows an example of the supports being used as heterogeneous catalysts.

(9) FIG. 5A shows the hydrogenation of benzene into cyclohexane.

DETAILED DESCRIPTION OF THE INVENTION

(10) Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The drawings may not be to scale. The same reference indicators will be used throughout the drawings and the following detailed description to refer to identical or like elements. In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application, safety regulations and business related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort will be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

(11) The following description of the invention is provided as an enabling teaching which includes the best, currently known embodiment. One skilled in the relevant arts, including but not limited to chemistry and physics, will recognize that many changes can be made to the embodiment described, while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and may even be desirable in certain circumstances, and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not in limitation thereof, since the scope of the present invention is defined by the claims. The terms nanoparticle, nanoparticle powder, and nano powder are generally understood by those of ordinary skill to encompass a quantity of material comprising particles on the order of nanometers in diameter, as described herein.

(12) FIG. 3 illustrates the inventive steps for a process 300 of forming a plug and play catalyst for use in such industries as chemical manufacturing. The method begins at the step 310. A quantity of at least one precursor material 312 is loaded into a plasma gun 315. Preferably, the precursor 312 comprises any among an oxide, a metal, a metal oxide, a metal salt, a chlorine compound, phosphorous compound, or any combination thereof. Alternatively, an oxide catalyst is loaded into the plasma gun 315. Oxides are well known and studied in the field of chemistry. Many oxide combinations exist, each having applications in industry. This disclosure focuses on oxides having catalytic properties. Oxides having catalytic properties include metal oxides, nonmetal oxides, and oxide-oxide bonded particles. Particularly, some oxides are used in heterogeneous catalysis, wherein the catalyst is in a different phase than the reactants. Heterogeneous catalysts provide a surface for the chemical reaction to take place on or otherwise activate the reaction. Next, in the step 320, the plasma gun 315 vaporizes the precursor 312 to form a vapor cloud 325. By way of example, if the desired oxide catalyst is lanthanum iron oxide, multiple permutations of precursor 312 are amenable to that end. One permutation includes loading a quantity of pre-formed lanthanum iron oxide, a commercially available material, into the plasma gun 315. Another permutation includes loading a quantity of lanthanum oxide and iron into the gun 315. In still another permutation, lanthanum and iron are loaded into the plasma gun 315 and the resulting vapor cloud 325 is combined with ambient oxygen. Alternatively, oxygen or an oxygen containing compound is injected into the reaction chamber. Also, more complex oxides having multiple components are contemplated. It will be apparent to those of ordinary skill that many different permutations are amenable to the process described herein with a vast array of starting compounds.

(13) Still referring to FIG. 3, the resulting vapor cloud 325 is then put through a quenching step 330. Preferably, the quenching step occurs in a highly turbulent quench chamber to facilitate rapid, even, consistent quenching of the vapor 325 into precipitate nanoparticles 400. Such a rapid quench chamber is described in detail in U.S. patent application Ser. No. 12/151,935, filed on May 8, 2008, which published as U.S. Patent Publication No. 2008-0277267 and is hereby incorporated by reference. As the gaseous oxide particles cool, they solidify into nanoparticles 400. An example of a resulting nanoparticle 400 is shown in FIG. 4A. The particles 400 will generally be in the range of 0.5 to 200 nm in size, and can be as small as a molecular length of the catalyst material and as large as would be achievable by ball milling. The particle size is able to be varied with varying starting materials, vaporization speeds, quench speeds and plasma temperatures.

(14) In some embodiments, the process 300 continues with step 340, where the nanoparticles 400 are combined with a liquid to form a dispersion 345. Preferably, a liquid that will not react with the catalyst or precursor materials is used. Some appropriate liquids are aqueous solutions or organic solutions employing solvents such as alcohols, ethers, hydrocarbons, esters, amines, or the like. Since the nanoparticles 400 are small, other precautions are generally taken to ensure that they suspend evenly within the dispersion. To that end, an adjunct 348 is able to be added to the dispersion. The adjunct 348, also referred to commonly in the art as a surfactant or dispersant, adheres to the nanoparticles 400 and causes them to repel each other, thereby causing the nanoparticles 400 to suspend evenly in the dispersion 345. The dispersion 345 is also referred to as a suspension.

(15) Referring back to FIG. 3, it is important to note that nanoparticles 400 such as the one shown in FIG. 4 are not generally compatible with existing processes for chemical conversion. For compatibility with existing processes, the nanoparticles 400 are bonded to a support. When the nanoparticles 400 are bonded to a support, nanoparticle 400 provides a surface where reactions are able to take place or where reactions are activated. To that end, more steps are taken to bring the nanoparticles 400 to a useable form. To bring the nanoparticles 400 closer to a usable catalyst, the nanoparticles 400 are impregnated onto supports 355. The supports 355 are also known to those skilled in the relevant art as porous oxides. Alternatively, the supports 355 are also referred to as extrudates because they are generally made using an extrusion process. The supports 355 are similar to the supports 104b in FIGS. 1 and 2. Such supports have found utility due to their highly accessible and large surface area, as high as 250 m.sup.2/g. In alternative embodiments, a macroscopic support particle is able to be used. In such an embodiment, the size of the macroscopic support particle is selected to provide maximum surface area to which nanoparticles 400 are bonded or fixed. The step 350A shows the preferred embodiment of achieving the impregnation. The dispersion 345 is combined with a quantity of substantially dry porous supports 355A to form a mixture 359A. Alternatively, as shown in the step 350B, the dispersion 345 is combined with a slurry 358 having macroscopic support particles 355B suspended therein, thereby forming the mixture 359B. The slurry 358 is able to be a suspension of water, alcohol, or any suitable organic or inorganic liquid which will not react with the macroscopic supports 355B or nanoparticles 400. In the step 350A, capillary forces will draw in the dispersion 345, and in turn the nanoparticles 400, into the various voids and pores within the structure of the porous supports 355A, thereby forming impregnated porous supports 365A. To aid in the impregnation, the mixture can be agitated or subjected to heat or pressure. In the step 350B, nanoparticles 400 come to rest on the surfaces of macroscopic supports thereby forming impregnated macro supports 365B. In some embodiments, the steps 350A or 350B are repeated at least once for enhanced impregnation.

(16) Next, in the steps 360A and 360B, the impregnated porous supports 365A or macro supports 365B are allowed to dry. A close up view the impregnated porous support 365A is shown in FIG. 4B. As the liquid in the dispersion 345 evaporates, the nanoparticles 400 settle onto the surface of the support 365A and into the pores 367 within the support 365A. FIG. 4C shows an example of an impregnated macro support 365B. As the liquids in the dispersion 345 and slurry 358 dry, nanoparticles 400 settle onto the surface of the macro support 365B. When the impregnated porous supports 365A or macro supports 365B dry, electrostatic interactions and other non covalent forces between the nanoparticles 400 and the porous supports 365A or macro supports 365B effectuate some adhesion. Advantageously, such forces cause the nanoparticles 400 to stick onto the surfaces and pores 367 of the supports 365A or 365B, and effectuate transfer of the supports 365 through the remainder of the process 300. Referring back to FIG. 3, a calcining step 370A or 370B is performed to form oxide-oxide bonds between the nanoparticles 400 and the impregnated supports 365A or 365B by exposing them to heat 372, pressure 375, or a combination thereof. The calcining temperature is generally from 350 to 1000 degrees centigrade, and the pressure is on the order of ambient atmosphere to several atmospheres. Due to the physical and chemical bond between the supports 365A and 365B and the nanoparticles 400, islands of nanoparticles 400 that are bonded, fixed or otherwise pinned to the surfaces of the supports 365A or 365B will not migrate and coalesce during catalytic conversion. The surface area for catalysis remains high, and therefore the catalytic activity remains high. In effect, operations such as fine chemical plants and oil refineries will not be required to stop operations and swap out ineffective catalyst supports with fresh catalyst supports with the same frequency as existing processes, thereby increasing throughput at the plants and refineries and reducing their overall cost of operation.

(17) FIG. 5 shows an example of the impregnated porous supports 365A being used in the fine chemical industry to hydrogenate benzene into cyclohexane. Macro supports 365B are able to be used as well. Although this example details use in the fine chemical industry, it will be apparent to those of ordinary skill in the arts of chemistry, chemical engineering, or the like that any process using heterogeneous catalysis is able to benefit from this disclosure. An amount of impregnated porous supports 365A is loaded into a reactor 510. Preferably, the reactor 510 has a mesh opening 515 on one end wherein the meshing has a smaller opening pitch than the size of the supports 365 such that the supports 365 do not fall through the opening 515. Benzene is passed into the vat 511 via the conduit 520. As the benzene passes through the vat 511, the benzene fills into the voids and pores of the support 365A.

(18) FIG. 5A shows an example of a benzene molecule 525 being hydrogenated into cyclohexane 525A in a cross section of a pore 367. When the benzene molecule 525 comes into contact with the nanoparticle 400 that is bonded to the surface of the support 365A, nanoparticle 400 will effectuate hydrogenation of the benzene molecule 525 and hydrogen molecules 525B into cyclohexane 525A without losing any energy to heat or risking uncontrolled burning or combustion.