Apparatus for processing materials in supercritical fluids and methods thereof

• US 20060177362A1
• Filed: 01/25/2005
• Published: 08/10/2006
• Est. Priority Date: 01/25/2005
• Status: Active Grant

• Current Assignee: SL Technology Incorporated (Reliv' International, Inc.)
• Original Assignee: Momentive Performance Materials Incorporated (Momentive Performance Materials Holdings LLC)
• Inventors: Dey, Subhrajit, D'Evelyn, Mark Philip, Sharifi, Fred, Giddings, Robert Arthur, Hong, Huicong, Kapp, Joseph Alexander, Khare, Ashok Kumar
• Granted Patent: US 7,704,324 B2
• Time in Patent Office: Days
• US Class Current: 422/245.100
• CPC Class Codes: B01J 2203/0665 Gallium nitrides
• CPC Class Codes: B01J 2203/068 Crystal growth
• CPC Class Codes: B01J 2219/00135 Electric resistance heaters
• CPC Class Codes: B01J 2219/00155 using insulating materials or refractories
• CPC Class Codes: B01J 2219/00162 controlling the pressure
• CPC Class Codes: B01J 3/002 Component parts of these vessels not mentioned in B01J3/004, B01J3/006, B01J3/02 - B01J3/08; Measures taken in conjunction with the process to be carried out, e.g. safety measures
• CPC Class Codes: B01J 3/008 Processes carried out under supercritical conditions
• CPC Class Codes: B01J 3/03 Pressure vessels, or vacuum vessels, having closure members or seals specially adapted therefor
• CPC Class Codes: B01J 3/046 Pressure-balanced vessels
• CPC Class Codes: B01J 3/06 Processes using ultra-high pressure, e.g. for the formation of diamonds; Apparatus therefor, e.g. moulds or dies B01J3/04 takes precedence
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids
• CPC Class Codes: Y10T 117/10 Apparatus
• CPC Class Codes: Y10T 117/1024 for crystallization from liquid or supercritical state
• CPC Class Codes: Y10T 117/1092 Shape defined by a solid member other than seed or product [e.g., Bridgman-Stockbarger]

Abstract

An apparatus and method for processing materials in supercritical fluids is disclosed. The apparatus includes a capsule configured to contain a supercritical fluid, a high strength enclosure disposed about the capsule and a sensor configured to sense pressure difference between an interior and an exterior of the capsule. The apparatus also includes a pressure control device configured to adjust pressure difference of the capsule in response to the pressure difference sensed by the sensor. The apparatus further includes at least one dividing structure disposed within the capsule that divides the capsule into a seed growing chamber and a nutrient chamber.

Claims

1. An apparatus comprising:

a capsule configured to contain a supercritical fluid;

a pressure vessel disposed about the capsule, wherein the pressure vessel is configured to contain a pressurized gas surrounding the capsule; and

a pressure control device configured to balance an interior pressure within the capsule with a surrounding pressure of the pressurized gas within the pressure vessel in response to sensed environmental conditions within the capsule or the pressure vessel.

2. The apparatus of claim 1, comprising a pressure sensor disposed inside the capsule, wherein the pressure sensor is configured to measure the interior pressure.

3. The apparatus of claim 1, comprising a displacement measuring device configured to measure deformation of the capsule due to a pressure difference between the interior pressure and the surrounding pressure.

4. The apparatus of claim 1, comprising at least one perforated baffle plate disposed within the capsule dividing the capsule into a first chamber and a second chamber, wherein the at least one perforated baffle plate comprises a central opening and a plurality of openings disposed symmetrically around the central opening.

5. The apparatus of claim 1, comprising temperature and pressure sensors disposed inside the capsule and/or between the pressure vessel and the capsule, wherein the temperature and pressure sensors are configured to enable feedback-based control of environmental conditions within the capsule and to enable feedback-based control to balance the interior and surrounding pressures of the capsule.

6. The apparatus of claim 1, wherein the capsule is deformable, chemically inert, and substantially impermeable to the supercritical fluid.

7. The apparatus of claim 1, comprising a gallium nitride crystal having an infrared absorption peak near 3175 cm⁻

1 with an absorbance per unit thickness between about 0.01 and 200 cm<sup>−

1</sup> and wherein the gallium nitride crystal is grown in supercritical ammonia at a temperature above 550 degrees Celsius.

8. An apparatus comprising:

a high strength enclosure;

a capsule disposed inside the high strength enclosure, wherein the capsule is configured to contain one or more materials in an environment having a supercritical fluid;

a heating device disposed between the high strength enclosure and the capsule, wherein the heating device is configured to transfer heat into the environment within the capsule, such that the environment becomes heated and self-pressurized from the heat, wherein the high strength enclosure is configured to surround and bear against the capsule to counterbalance internal pressures within the capsule; and

thermal insulation disposed between the high strength enclosure and the heating device, wherein the thermal insulation is configured to retain heat within the capsule and to reduce heat transfer into the high strength enclosure.

9. The apparatus of claim 8, comprising a cooling device configured to cool the high strength enclosure.

10. The apparatus of claim 8, wherein the apparatus is configured to increase the operating conditions within the capsule to pressures exceeding 1 kbar and temperatures exceeding 550 degrees Celsius or to pressures exceeding 5 kbar and temperatures exceeding 300 degrees Celsius.

11. The apparatus of claim 8, wherein the capsule is mechanically expandable and contractible, chemically inert, and impermeable to the supercritical fluid.

12. The apparatus of claim 8, comprising a temperature control system configured to control the heating device for controlling the temperature of the capsule.

13. The apparatus of claim 8, comprising a dividing structure disposed within the capsule dividing the capsule into a first chamber and a second chamber, wherein the dividing structure comprises a central opening and a plurality of openings disposed symmetrically around the central opening.

14. The apparatus of claim 8, comprising a high temperature liner disposed between the thermal insulation and the high strength enclosure.

15. The apparatus of claim 8, comprising a plurality of radial segments disposed one after another around a circumference of the capsule inside the high strength enclosure.

16. The apparatus of claim 8, wherein the capsule comprises a sleeve having a larger thermal expansion coefficient than the heating element.

17. The apparatus of claim 8, comprising a gallium nitride crystal having an infrared absorption peak near 3175 cm⁻

1 with an absorbance per unit thickness between about 0.01 and 200 cm<sup>−

1</sup> and wherein the gallium nitride crystal is grown in supercritical ammonia at a temperature above 550 degrees Celsius.

18. An apparatus comprising:

a pressure vessel configured to process material contained in a self pressurizing capsule, wherein the pressure vessel is configured to contain a pressurized gas surrounding the self-pressurizing capsule;

a displacement measuring device configured to measure deformation of the self-pressurizing capsule due to a pressure difference between an interior pressure and a surrounding pressure of the self-pressurizing capsule; and

a pressure control device configured to balance the interior pressure within the capsule with the surrounding pressure of the pressurized gas within the pressure vessel by minimizing displacement or deformation of the self-pressurizing capsule.

19. An apparatus comprising:

a high strength enclosure;

a heating device disposed inside the high strength enclosure and configured to receive a capsule, wherein the heating device is configured to transfer heat into the environment within the capsule, such that the environment becomes heated and self-pressurized from the heat, wherein the high strength enclosure is configured to surround and bear against the capsule to counterbalance internal pressures within the capsule without significant gas pressure between the heating device and the capsule; and

thermal insulation disposed between the high strength enclosure and the heating device.

20. A method of operation of an apparatus comprising:

identifying a differential between an interior pressure within a supercritical fluid capsule and a surrounding pressure between a pressure vessel and the supercritical fluid capsule disposed within the pressure vessel; and

adjusting the interior pressure or the surrounding pressure to substantially balance the differential between the interior pressure and the surrounding pressure.

21. The method of claim 20, comprising sensing displacement of the supercritical fluid capsule caused by the differential between the interior pressure and the surrounding pressure.

22. A method of manufacturing an apparatus comprising:

providing a high strength enclosure;

providing a capsule configured to be positioned inside the high strength enclosure, wherein the capsule is configured to contain a substance including a supercritical fluid,

providing a heating device configured to be positioned between the high strength enclosure and the capsule; and

providing thermal insulation configured to be positioned between the high strength enclosure and the heating device.