Tapered fluidized bed reactor and process for its use

• US 10,105,669 B2
• Filed: 08/26/2013
• Issued: 10/23/2018
• Est. Priority Date: 08/29/2012
• Status: Active Grant

• Current Assignee: Hemlock Semiconductor | Hemlock Semiconductor Operations LLC
• Original Assignee: Hemlock Semiconductor | Hemlock Semiconductor Operations LLC
• Inventors: Bucci, John V., Cocco, Raymond Anthony, Dehtiar, Max E., Harder, Patrick J., Karri, S. B. Reddy, Knowlton, Ted M., Molnar, Michael J.
• Primary Examiner(s): Do, An
• Application Number:
  US14/423,271
• Publication Number:
  US 20150217252A1
• Time in Patent Office: 1,884 Days
• Field of Search: 702 22, 702 29, 702 30, 422129, 422139
• CPC Class Codes: B01J 2208/00672 Particle size selection
• CPC Class Codes: B01J 2208/00752 Feeding
• CPC Class Codes: B01J 2208/00761 Discharging
• CPC Class Codes: B01J 2208/00902 Nozzle-type feeding elements
• CPC Class Codes: B01J 2208/00938 Flow distribution elements
• CPC Class Codes: B01J 2208/00982 Particulate material
• CPC Class Codes: B01J 2208/00991 Disengagement zone in fluidised-bed reactors
• CPC Class Codes: B01J 8/1827 the fluidising gas being a reactant
• CPC Class Codes: B01J 8/1836 Heating and cooling the reactor B01J8/42 takes precedence
• CPC Class Codes: B01J 8/1872 Details of the fluidised bed reactor B01J8/1836 takes precedence
• CPC Class Codes: B01J 8/24 according to "fluidised-bed" technique B01J8/20 takes precedence
• CPC Class Codes: B01J 8/44 Fluidisation grids
• CPC Class Codes: C01B 33/027 by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
• CPC Class Codes: C01B 33/03 by decomposition of silicon halides or halosilanes or reduction thereof with hydrogen as the only reducing agent
• CPC Class Codes: G01N 15/0255 with mechanical, e.g. inertial, classification, and investigation of sorted collections with centrifuges G01N15/042

Abstract

A fluidized bed reactor includes a gas distributor, a tapered section above the gas distributor, and an expanded head above the tapered section. The gas distributor defines a plurality of inlets surrounding a product withdrawal tube, which extends away from the fluidized bed reactor. The fluidized bed reactor is useful in a process for fluidizing relatively large particles, such as Geldart Group B particles and/or Geldart Group D particles, where said particles are in a bubbling fluidized bed residing, in whole or in part, in the tapered section. The fluidized bed reactor and process may be used for manufacturing polycrystalline silicon.

Claims

1. A fluidized bed reactor comprising:

a conical gas distributor having a top edge,

a product withdrawal tube mounted to the gas distributor,

a plurality of feed inlets defined by the conical gas distributor between the top edge and

the product withdrawal tube;

a tapered section above the conical gas distributor, where the tapered section of the fluidized bed reactor expands upward and outward from the top edge of the conical gas distributor; and

an expanded head above the tapered section, wherein a diameter of the expanded head is larger than a diameter of the tapered section; and

wherein the slope of the expanded head with respect to the horizontal plane of the transition point is at least 40 degrees.

2. The fluidized bed reactor of claim 1, further comprising at least one straight section selected from:

a lower straight section located above the conical gas distributor and below the tapered section,

an upper straight section located above the tapered section and below the expanded head, or

both the lower straight section and the upper straight section.

3. The fluidized bed reactor of claim 1, where the tapered section expands upward and outward at a cone angle ranging from 2.5°

to 10.0°

from vertical.

4. The fluidized bed reactor of claim 1, further comprising a plurality of gas inlets, where the gas inlets are defined by the conical gas distributor, and the gas inlets are located between the feed inlets and the top edge of the conical gas distributor.

5. The fluidized bed reactor of claim 1, further comprising a heater oriented to the fluidized bed reactor, so as to provide heat to the tapered section when the heater operates, a supplemental heater oriented to the fluidized bed reactor so as to provide heat at the conical gas distributor when the supplemental heater operates, and a straight section heater oriented to the fluidized bed reactor, so as to provide heat to the at least one straight section when the straight section heater operates.

6. The fluidized bed reactor of claim 1, further comprising a bubbling fluidized bed comprising Geldart Group D particles residing at least in part in the tapered section, where the particles are silicon particles.

7. The fluidized bed reactor of claim 6, further comprising an accelerometer coupled to the fluidized bed reactor for measuring vibrations of the fluidized bed reactor to determine a Sauter mean particle size distribution of the particles.

8. A fluidized bed reactor of claim 1, further comprising at least one row of gas injection ports defined by the tapered section to add additional feed gas, etching gas or diluent gas.