Apparatus and Method for Making Spherical Catalyst Beads

Abstract

Apparatuses and methods for making uniform spherical beads are disclosed. Specifically, the uniform spherical beads are made by dropping droplets on a droplet rolling part, creating beads by rolling the droplets on the droplet rolling part from one spot to another spot, and collecting the beads by a beads collector.

Claims

1. An apparatus for making spherical beads from a liquid suspension, comprising: a droplet generating device for generating droplets; a droplet rolling part comprising at least one omniphobic-coated plate; and a beads collector, wherein the droplets move from one spot of the droplet rolling part to another spot before reaching the beads collector.

2. The apparatus according to claim 1, wherein the droplet generating device comprises a fluid reservoir and a tip.

3. The apparatus according to claim 1, wherein the size of the droplets is adjustable by adjusting the volume of the liquid suspension in the droplet generating device.

4. The apparatus according to claim 1, wherein the at least one omniphobic-coated plate is inclined.

5. The apparatus according to claim 4, wherein the angle between the omniphobic-coated plate and the horizontal plane is between 0 and 90 degrees.

6. The apparatus according to claim 1, wherein the droplet rolling part further comprises at least one heating element.

7. The apparatus according to claim 6, wherein the droplet rolling part is heated to a temperature between about 80 C. and about 120 C.

8. The apparatus according to claim 1, wherein the at least one omniphobic-coated plate comprises a super-omniphobic coating layer on the surface.

9. The apparatus according to claim 1, wherein the at least one omniphobic-coated plate is superhydrophobic, superoleophobic, thermal stable and durable.

10. The apparatus according to claim 1, wherein the beads collector comprises a omniphobic-coated plate for collecting spherical beads.

11. The apparatus according to claim 1, wherein the beads collector further comprises at least one heating element.

12. A method of making spherical beads from a liquid suspension, comprising: supplying droplets of a liquid suspension; dropping the droplets on one spot of a droplet rolling part, wherein the droplet rolling part comprises at least one omniphobic-coated plate; creating beads by rolling the droplets on the droplet rolling part from one spot to another spot; and collecting the beads by a beads collector.

13. The method according to claim 12, wherein the rolling step further comprises heating the droplet rolling part.

14. The method according to claim 13, wherein the droplet rolling part is heated to a temperature between 80 C. and 120 C.

15. The method according to claim 12, wherein the beads collector is heated to a temperature between 80 C. and 120 C.

16. The method according to claim 12, wherein the beads have an average diameter in a range of 100 microns (m) to 12 millimeters (mm).

17. The apparatus according to claim 12, wherein the at least one omniphobic-coated plate comprises a super-omniphobic coating on the surface.

18. The apparatus according to claim 12, wherein the at least one omniphobic-coated plate is superhydrophobic, superoleophobic, thermal stable and durable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several embodiments described below.

[0014] FIG. 1 illustrates embodiments of an apparatus for making spherical catalyst beads including heating elements.

[0015] FIGS. 2A-2C illustrate embodiments of an apparatus including a droplet rolling part of: (A) three omniphobic-coated plates, (b) funnel design, and (c) spiral design.

[0016] FIG. 3 illustrates the spherical Aluminum catalyst beads formed according to some embodiments of the present disclosure.

[0017] FIG. 4 illustrates the spherical aluminum oxide beads formed according to some embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0018] Before describing several exemplary embodiments, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following disclosure. The disclosure provided herein is capable of other embodiments and of being practiced or being carried out in various ways.

[0019] Embodiments of the present disclosure provide apparatuses and methods for making spherical beads, preferably spherical catalytic beads, having an average diameter in a range of 100 microns (m) to 12 millimeters (mm).

[0020] FIG. 1 is a brief schematic of an apparatus 100 for making spherical beads. The apparatus 100 has three parts. The first part is the droplet generating device 10. The droplet generating device 10 includes a fluid reservoir 11, and a tip 12 , from which the droplets can be dispensed. In some examples, the droplet generating device 10 is a micro-pipette, from which droplets of micro-liter volume are dispensed through the pipette tip.

[0021] The second part is a droplet rolling part 20, which includes at least one omniphobic-coated plate 21. As used herein, the term omniphobic means repellent to both watery and oily liquids. The omniphobic-coated plate 21 can have three layers: a metal panel 22 (such as an Aluminum plate), a omniphobic coating layer on the surface of the metal panel 23, and at least one heating element attached to the other surface of the metal panel 24. In some examples, the at least one omniphobic-coated plate 21 is inclined, and the angle between the at least one omniphobic-coated plate 21 and the horizontal plane can be between 0 and 90 degrees. In some other examples, the droplet rolling part is heated to a temperature not capable of causing deformation of the omniphobic coating layer 23. The temperature is preferably between about 80 C. and about 120 C. In another example, the omniphobic coating layer is a super-omniphobic coating layer. As used herein, the term super-omniphobic means superhydrophobic (offering low surface tension), superoleophobic, thermal stable and durable. The coatings super-hydrophobicity provides the surface with a low surface energy, so that the water based suspension will not stick to it. Similarly, an oil-based liquids suspension will not adhere to the super-oleophobic surface. In certain examples, the terms omniphobic and super-omniphobic have the same meaning and can be used interchangeably. The omniphobic or super-omniphobic coating layer can withstand a temperature without deformation of at least 100 C.

[0022] The third part is a beads collector 30, which includes a omniphobic-coated plate 31 for collecting the spherical beads 32. The omniphobic-coated plate 31 has three layers: a metal panel 32 (such as an Alumina plate), a omniphobic coating layer 33on the surface of the metal panel, and at least one heating element 34attached to the other surface of the metal panel.

[0023] A liquid suspension containing a solvent and at least one metal/metalloid oxide compound such as aluminum hydroxide or silicon oxide, serving as a catalyst or catalyst carrier, is dispensed dropwise onto the heated omniphobic-coated plate 21 to form hardened spherical beads. The liquid suspension may also comprise other metal/metalloid oxide, or carbonate compounds, such as calcium carbonate, titanium dioxide, and aluminum silicate. A omniphobic coating layer 23 can prevent the liquid droplets from adhering to the plate surface and retain the droplets spherical shape in air, prior to hardening. With a slight tilt of the plate, the droplets roll to produce nearly spherical shaped and uniform catalyst beads comprising of the at least one metal/metalloid oxide compound or carbonate compounds. It should be pointed out that the disclosed methods can be applied to manufacture other spherical particles such as catalytic carriers, abrasives, or adsorbents with metal/metalloid oxide, or carbide compound.

[0024] The liquid catalyst suspension is stored in the fluid reservoir 11. When the apparatus is in use, the droplets are formed and dropped from the tip of the tip 12. In some examples, the droplets drop on one spot of the droplet rolling part 20. The droplets then move to another spot of the droplet rolling part 20 before dropping onto the beads collector 30. When the omniphobic-coated plate 21 is inclined, gravity can drive the movement of the droplets. In other examples, the droplets can move by other mechanisms, e.g., by vacuum force, blowing, or through a mechanical movement. The vertical distance between the tip 12 and the dropping position of the omniphobic-coated plate 21 is between 0 to 3 centimeters. The liquid droplets then roll along the length of the plate into the collector plate. During the rolling, the liquid encompassing the droplets is evaporated, and the droplets form dried spherical beads. The spherical beads are accumulated in the beads collector 30. The beads collector 30 is preferably heated for further drying and collection. The rolling time can be adjusted by adjusting the vertical distance and/or the angle between the omniphobic-coated plate 21 and the horizontal plane.

[0025] In some embodiments, the beads collector 30 is a part of the droplet rolling part 20, wherein the omniphobic-coated plate 21 comprises an inclined part for rolling the beads and a horizontal part for collecting the beads.

[0026] FIGS. 2A-2C illustrate various embodiments of the droplet rolling part 20. In FIG. 2A, the droplet rolling part 20 has three omniphobic-coated plates 21a, 21b, and 21c. In some examples, the three omniphobic-coated plates have different tilt angles in order to adjust the droplet rolling speed or for other purposes. FIGS. 2B and 2C illustrate two more configurations of the droplet rolling part 20. FIG. 2B is a funnel structure, wherein the omniphobic coating layer 23 is on the funnel inside surface. The beads collector 30 is placed under the stem of the funnel. The at least one heating element is outside of the funnel. Similarly, FIG. 2C illustrates a spiral structure located in a temperature controlled chamber.

[0027] According to one or more embodiments, the omniphobic-coated plate can be made by coating an omniphobic material on the metal panel. US Patent Pub. Nos. 20170260420, 20160339625, 20140023852, and 20140011013, and U.S. Pat. Nos. 9,823,174 and 9,108,880, and pending U.S. patent application Ser. No. 15/891,870 provide methods to make the omniphobic coating layer and the omniphobic-coated plate.

[0028] The disclosure also provides methods of making spherical beads. In one or more embodiments, the method comprises supplying droplets of a liquid suspension; dropping the droplets on one spot of a droplet rolling part; creating beads by rolling the droplets on the droplet rolling part from one spot to another spot; and collecting the beads by a beads collector. In some embodiments, the droplet rolling part comprises at least one omniphobic-coated plate. In some further embodiments, the rolling step further comprises heating the droplet rolling part. The temperature can be between 80 C. and 120 C. In still further embodiments, the beads collector is heated to a temperature between 80 C. and 120 C. Heating can evaporate water in the droplets and facilitate hardening of the droplets to form beads. The beads have an average diameter in a range of 100 microns (m) to 12 millimeters (mm).

Embodyment 1

[0029] A super-omniphobic coating was coated on aluminum (Al) plates as shown in FIG. 2. The super-omniphobic coating plates are prepared using the method disclosed in the co-pending patent application Ser. No. 15/891,870. The plates were heated to an average temperature of 90 C. (temperature range of 85-95 C.) by the heating elements before making spherical catalyst beads. The liquid catalyst suspension comprised AlO.sub.2, hexamethylenetetramine for gelling, and water. An automated micro-pipette dispensing systems pipette tip was used as the droplet generating device. The droplet was about 10 l of the liquid catalyst suspension (AlO.sub.2). After dropping, the AlO.sub.2 liquid catalyst suspension droplet traveled vertically about 1-13 cm to the dropping position on the super-omniphobic coated plate, rolled down through the super-omniphobic coating plates, and dropped into the beads collector.

[0030] The low surface energy of the super-omniphobic coating resulted in the liquid catalyst suspension forming and retaining its spherical shape along the plate. The water used in the AlO.sub.2 liquid catalyst suspension was slowly evaporated off by the heated plates, and the AlO.sub.2 catalyst material solidified into nearly uniform spherical beads. The average diameter of the 10 l solution of AlO.sub.2 liquid catalyst suspension was about 3.55 mm. 10 l solution of AlO.sub.2 liquid catalyst suspension formed a 2.67 mm diameter uniform sphere after drying. An image of a sphere is shown in FIG. 4. The catalyst beads dried/gelled within at least two to five minutes after dropping. Additional heat treatment such as calcination was needed to fully harden the beads. FIG. 5 shows the spherical catalyst beads

Embodyment 2

[0031] The plates were heated to an average temperature of 90 C. by the heating elements before making spherical catalyst beads. The droplets were each about 5 l of the liquid catalyst suspension (AlO.sub.2). The average diameter of the 5 l solution of AlO.sub.2 liquid catalyst suspension was about 2.77 mm. 5 l solution of AlO.sub.2 liquid catalyst suspension formed a 2.02 mm diameter uniform sphere after drying.

Embodyment 3

[0032] The plates were heated to an average temperature of 90 C. by the heating elements before making spherical catalyst beads. The droplets were each about 2.5 l of the liquid catalyst suspension (AlO.sub.2). The average diameter of the 2.5 l solution of AlO.sub.2 liquid catalyst suspension was about 2.14 mm. 2.5 l solution of AlO.sub.2 liquid catalyst suspension formed a less than 2 mm diameter uniform sphere after drying.

Embodyment 4

[0033] The plates were heated to an average temperature of 90 C. by the heating elements before making spherical catalyst beads. The droplets were each about 1 l of the liquid catalyst suspension (AlO.sub.2). The average diameter of the 1 l solution of AlO.sub.2 liquid catalyst suspension was about 1.54 mm. 1 l solution of AlO.sub.2 liquid catalyst suspension formed a less than 1 mm diameter uniform sphere after drying.

[0034] The diameter of spherical catalyst beads

TABLE-US-00001 Liquid Diameter catalyst Diameter (solid suspension (liquid AlO.sub.2 AlO.sub.2) Volume (L) sol) (mm) (mm) 10 3.55 2.67 +/ 0.176 5 2.77 2.02 +/ 0.04 2.5 2.14 <2.00 1 1.54 <1.00