TWI863311B - Gas reforming catalyst assembly - Google Patents

Abstract

A gas reforming catalyst assembly includes a catalyst carrier and a catalyst. The catalyst carrier includes a first surface and a second surface, and the distance between the first surface and the second surface is 5 to10mm. A plurality of holes are formed on the catalyst carrier, and the holes extends along a direction from the first face towards the second face, the distance between an end portion each hole near the second face and the second face is 0.5 to 1mm. The catalyst carrier accounts for 90 to 98wt%, containing zinc oxide, and having a porosity of 20 to 65%. The catalyst is on the first surface of the catalyst carrier and in the holes, and the catalyst is cerium oxide and nickel oxide. Using zinc oxide as the catalyst carrier can reduce the particle growth of the catalyst under high temperature operation. In addition, the design of the holes facilitates the transmission of gas and increases the contact area to achieve a better catalytic effect.

Description

Gas reforming catalyst assembly

The present invention relates to the field of hydrogen energy, and in particular to a gas reforming catalyst assembly for reforming biomass fuel gas.

Solid-state batteries/fuel cells are devices that convert chemical energy into electrical energy. They have the advantages of high energy conversion efficiency and low environmental impact. The main fuel used in solid-state batteries is hydrogen. Although hydrogen has the advantage of being clean, its volume density and safety cause problems in transportation and storage.

In the transition period before solving these problems, liquid hydrocarbon fuels such as methanol and ethanol are usually used. Methanol and ethanol can be obtained from plant seeds or biomass such as starch. Because this type of alcohol can be regenerated, it is called "bioalcohol". The hydrogen obtained by cracking and transforming bioalcohol into small molecule fuels is called green hydrogen. This hydrogen is chemically converted into electricity through solid batteries/fuel cells. At the same time, the heat and carbon dioxide generated can be recycled to improve economic efficiency. The generated electricity has the highest carbon rights in the carbon economy and is a green product that future electric vehicles and green economy attach great importance to.

The process of converting hydrocarbon fuel gas into hydrogen and carbon monoxide is called "gas reforming". It is usually carried out in a reformer in a high-temperature furnace. In order to accelerate the reaction rate, a catalyst is usually placed on the gas pipeline of the reformer. The catalyst is usually placed on a catalyst carrier, and the catalyst carrier is preferably a ceramic oxide. The most commonly used commercial material today is transient alumina. This alumina is sintered at 1000 degrees Celsius to produce porous spheres with a diameter of 3 to 5 mm and a high specific surface area. When the sphere is immersed in a catalyst precursor solution, such as a precursor chemical solution of nickel oxide or potassium oxide, and then calcined, nano-scale nickel oxide and potassium oxide submicron particles can be obtained to serve as a catalyst.

However, high specific surface area is also prone to side effects. At higher operating temperatures of solid-state batteries, the alumina particles of the catalyst carrier and the catalyst particles will grow, causing the surface area to gradually decrease, thus losing the original advantage of high specific surface area, and thus reducing the rate of the catalytic reaction. In addition, in the reforming of biomass fuels, in the lower temperature section, there is usually an incomplete reaction, and methane or other free carbon is produced, which is easy to accumulate on the surface of the catalyst carrier, which also reduces the catalytic reaction rate.

To solve the above problems, in some embodiments, a gas reforming catalyst assembly is provided. The gas reforming catalyst assembly includes a catalyst carrier and a catalyst. The catalyst carrier includes a first surface and a second surface, and the distance between the first surface and the second surface is 5 to 10 mm. The catalyst carrier has a plurality of holes extending from the first surface to the second surface, and the distance between the end of each hole close to the second surface and the second surface is 0.5 to 1 mm, and the catalyst carrier accounts for 90 to 98 wt%, includes zinc oxide (ZnO), and has a porosity of 20 to 65%. The catalyst is located on the first surface of the catalyst carrier and the wall of the hole, and the catalyst is caesium oxide (CeO ₂ ) and nickel oxide (NiO ₂ ).

In some embodiments, the gas reforming catalyst assembly further includes a surface coating, the surface coating is located on the surface of the catalyst carrier, and the surface coating is copper oxide (CuO), accounting for a weight percentage of less than 1wt%.

In some embodiments, the catalyst carrier further comprises yttrium oxide (Y ₂ O ₃ ) or aluminum oxide (Al ₂ O ₃ ), and the content of yttrium oxide or aluminum oxide is less than 1 wt %.

In some embodiments, the catalyst carrier has a diameter of 5 to 40 cm.

In some embodiments, the distance between holes is greater than 1 mm.

In some embodiments, the hole diameter on the first side is larger than the hole diameter at the end.

More specifically, in some embodiments, the aperture of the hole tapers from the first surface toward the end.

Furthermore, in some embodiments, the hole has a stepped slope from the first surface toward the end.

In some embodiments, the catalyst carrier has a porosity of 30 to 60%.

Preferably, in some embodiments, the porosity of the catalyst carrier is 45 to 58%.

As described in the above embodiment, the gas reforming catalyst assembly uses zinc oxide to replace the traditional aluminum oxide. Under high temperature operation, the growth rate of the catalyst particles is reduced, while maintaining the effect of the catalyst, avoiding the production of byproducts such as methane, and avoiding the poisoning phenomenon caused by carbon deposition. In addition, under the premise of maintaining rigidity, the design of holes is conducive to the transmission of gas, so that the contact area between gas and catalyst can be increased, achieving a better gas reforming effect.

1: Gas reforming catalyst assembly

10: Catalyst carrier

11: First page

13: Second side

15: Holes

151: End

17: Micropores

20: Catalyst

30: Surface coating

D1: The distance between the first and second surfaces

D2: Distance from the end to the second surface

Figure 1 is a three-dimensional diagram of an embodiment of a gas reforming catalyst assembly.

Figure 2 is a partially enlarged cross-sectional view of an embodiment of a gas reforming catalyst assembly.

Figure 3 is a partially enlarged cross-sectional view of another embodiment of the gas reforming catalyst assembly.

Figure 4 is a partially enlarged cross-sectional view of another embodiment of the gas reforming catalyst assembly.

It should be understood that when an element is referred to as being "disposed" on another element, it can mean that the element is directly located on the other element, or there can be an intermediate element through which the element and the other element are connected. Conversely, when an element is referred to as being "directly disposed on another element" or "directly disposed to another element", it can be understood that this clearly defines that there is no intermediate element.

In addition, the terms "first", "second", and "third" are only used to distinguish one element, component, region, or part from another element, component, region, layer, or part, rather than to indicate a necessary order of precedence. In addition, relative terms such as "lower" and "upper" may be used herein to describe the relationship between one element and another element, and it should be understood that the relative terms are intended to include different orientations of the device other than the orientation shown in the figure. For example, if a device in an accompanying figure is flipped, the element described as being on the "lower" side of the other elements will be oriented on the "upper" side of the other elements. This only indicates a relative orientation relationship, not an absolute orientation relationship.

FIG1 is a three-dimensional diagram of an embodiment of a gas reforming catalyst assembly. FIG2 is a partially enlarged cross-sectional diagram of an embodiment of a gas reforming catalyst assembly. As shown in FIG1 and FIG2, the gas reforming catalyst assembly 1 includes a catalyst carrier 10 and a catalyst 20. The catalyst carrier 10 includes a first surface 11 and a second surface 13, and the distance D1 between the first surface 11 and the second surface 13 is 5 to 10 mm. The catalyst carrier 10 has a plurality of holes 15. Here, FIG2 only shows a single hole 15 to show that the hole 15 extends from the first surface 11 to the second surface 13. The distance D2 between the end 151 of each hole 15 close to the second surface 13 and the second surface 13 is 0.5 to 1 mm.

The catalyst carrier 10 accounts for 90 to 98 wt %, preferably 94 to 97 wt %, of the gas reforming catalyst assembly 1. The catalyst carrier 10 contains zinc oxide and has a porosity of 20 to 65%. Preferably, the porosity of the catalyst carrier 10 is 30 to 60%. More preferably, the porosity of the catalyst carrier 10 is 45 to 58%.

The catalyst 20 is located in the first surface 11 of the catalyst carrier 10 and the wall gap of the hole 15. The catalyst 20 is tantalum oxide and nickel oxide. The catalyst 20 is mainly prepared by immersing the porous catalyst carrier 10 in a catalyst precursor and then calcining it. Under a microscope, the catalyst 20 is a nano-scale powder particle with a particle size of 0.02μm to 0.8μm. Based on actual experiments, zinc oxide was used as the catalyst carrier 10 and tadalafil/nickel oxide powder was used as the catalyst 20. After heat treatment at 650 degrees Celsius for 100 hours, the average particle size of tadalafil/nickel oxide particles on the surface of the catalyst carrier 10 only grew from 0.3μm to 0.6μm. In other words, replacing the existing commercial aluminum oxide with zinc oxide as the catalyst carrier 10 can slow down the growth rate of the catalyst 20, thereby extending the use time of the catalyst 20 and maintaining a better catalytic reaction effect.

Furthermore, by using doping to increase the efficiency of electron transfer and exchange, the speed of the catalytic reaction can be increased, so doping can be performed in ZnO, mainly doping with trivalent elements such as aluminum and yttrium. Therefore, the catalyst carrier 10 can be determined to contain oxides such as yttrium oxide ( _{Y2O3 )} and aluminum oxide ( _{Al2O3 )} by X-ray diffraction, and the content of the dopant is less than 1wt%.

The catalyst carrier 10 is mainly installed in the pipeline, and the diameter of the catalyst carrier 10 is 5 to 40 cm. However, in FIG1 , the catalyst carrier 10 is only exemplified as a disc, and is not intended to be limiting. In some embodiments, the catalyst carrier 10 may also be a flat plate.

Referring to FIG. 2 again, the gas reforming catalyst assembly 1 further includes a surface coating 30, which is copper oxide and accounts for less than 1wt% by weight. The surface coating 30 is usually formed after the catalyst 20 is placed on the catalyst carrier 10, and then immersed or sprayed in a copper-containing precursor liquid, such as copper acetate, copper nitrate, etc., and then heat-treated to coat the surface of the catalyst carrier 10 and the catalyst 20. The surface coating 30 prevents smaller carbon particles from being deposited on the surface of the gas reforming catalyst assembly 1, and can maintain a longer-lasting catalytic effect. Similarly, the surface coating 30 is actually observed under a microscope and is also nano-scale powder particles with a particle size of 0.02μm to 0.8μm.

Here, the first surface 11 is mainly the air inlet surface, receiving the biomass gas transported by the pipeline. Therefore, the hole 15 is used to increase the area of the catalyst 20 attachment and the surface area for the subsequent reaction between the biomass gas and the catalyst 20. At the same time, the catalyst carrier 10 needs to have a certain thickness, that is, the distance D1 between the first surface 11 and the second surface 13, to maintain the overall rigidity and strength to avoid damage caused by the impact of the gas transport. In addition, in order to maintain an effective catalytic effect, the distance between the holes 15 is designed to be greater than 1mm. The biomass gas then enters the hole 15 for reaction, and the converted hydrogen and carbon monoxide are gradually discharged through the fine pores of the catalyst carrier 10 itself.

Referring to FIG. 2 again, in some embodiments, the hole 15 has a diameter greater than the hole 15 at the end 151. That is, in the figure, the cross section of the hole 15 may be needle-shaped or cone-shaped, but this is only an example and not intended to be limiting. In fact, in other embodiments, the hole 15 may have the same diameter from the first surface 11 to the end 151.

Further, referring to FIG. 2 again, the enlarged view of the A region in FIG. 2 shows that the catalyst carrier 10 has a plurality of tiny micropores 17 between the end 151 and the second surface 13. In fact, the catalyst carrier 10 is a porous ceramic body, and the entire region, whether on the surface or inside, has micropores 17, and the micropores 17 can be interconnected. The pore diameter range of the micropores 17 is 20 to 100 nm. When the porous catalyst carrier 10 is immersed in the catalyst precursor, the catalyst precursor will enter the micropores 17, so that after calcination, the wall of the micropore 17 has a catalyst 20. In addition, after calcination, the catalyst 20 may precipitate in the form of sub-micron particles and form on the wall of the hole 15 and the micropore 17.

FIG3 is a partially enlarged cross-sectional view of another embodiment of the gas reforming catalyst assembly. FIG4 is a partially enlarged cross-sectional view of another embodiment of the gas reforming catalyst assembly. In the embodiments of FIG3 and FIG4, the structural design of the catalyst carrier 10 is mainly changed, so the catalyst 20 and the surface coating 30 are omitted. Similarly, only a single hole 15 is used to present different structural designs. As shown in FIG3, in some embodiments, the aperture of the hole 15 gradually decreases from the first surface 11 toward the end 151.

As shown in FIG. 4 , in some embodiments, the hole 15 has a stepped slope from the first surface 11 toward the end 151. This design can increase the attachment area of the catalyst 20 and also increase the area of the catalytic reaction.

In summary, the gas reforming catalyst assembly 1 uses zinc oxide to replace the traditional aluminum oxide. Under high temperature operation, the growth rate of the catalyst 20 particles is reduced, while maintaining the effect of the catalyst 20, reducing the production of byproducts such as methane, and avoiding the catalyst poisoning caused by carbon deposition. In addition, under the premise of maintaining rigidity and strength, the design of the hole 15 is conducive to the transmission of gas, and at the same time, the contact area between the gas and the catalyst 20 can be increased, achieving a better gas reforming effect.

Although the technical content of the present invention has been disclosed as above with the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with the ceramic process technology can make various thin-sheet-shaped catalyst carriers by appropriately making additives. Any slight changes and modifications made without departing from the spirit of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the attached patent application.

1: Gas reforming catalyst assembly

10: Catalyst carrier

11: First page

13: Second side

15: Holes

151: End

17: Micropores

20: Catalyst

30: Surface coating

D2: Distance from the end to the second surface

Claims (10)

A gas reforming catalyst assembly comprises: a catalyst carrier, comprising a first surface and a second surface, the distance between the first surface and the second surface is 5 to 10 mm, the catalyst carrier has a plurality of holes extending from the first surface to the second surface, the distance between each hole at an end close to the second surface and the second surface is 0.5 to 1 mm, and the catalyst carrier accounts for 90 to 98 wt%, contains zinc oxide, and has a porosity of 20 to 65%; and a catalyst, located on the first surface of the catalyst carrier and the wall of the holes, the catalyst is tantalum oxide and nickel oxide. The gas reforming catalyst assembly as described in claim 1 further comprises a surface coating, the surface coating is located on the surface of the catalyst carrier, and the surface coating is copper oxide, accounting for less than 1wt% by weight. The gas reforming catalyst assembly as described in claim 1, wherein the catalyst carrier further comprises yttrium oxide (Y ₂ O ₃ ) or aluminum oxide (Al ₂ O ₃ ), and the content of yttrium oxide or aluminum oxide is less than 1 wt %. A gas reforming catalyst assembly as described in claim 1, wherein the diameter of the catalyst carrier is 5 to 40 cm. A gas reforming catalyst assembly as described in claim 1, wherein the distance between the holes is greater than 1 mm. A gas reforming catalyst assembly as described in claim 1, wherein the hole diameters of the holes on the first side are larger than the hole diameters of the holes on the end side. A gas reforming catalyst assembly as described in claim 6, wherein the pores have a diameter that tapers from the first surface toward the end. A gas reforming catalyst assembly as described in claim 7, wherein the holes are stepped from the first surface to the end surface. A gas reforming catalyst assembly as described in claim 1, wherein the porosity of the catalyst carrier is 30 to 60%. A gas reforming catalyst assembly as described in claim 9, wherein the porosity of the catalyst carrier is 45 to 58%.

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