Multicomponent fluid feed apparatus with preheater and mixer for a high temperature chemical reactor

• US 5,935,528 A
• Filed: 01/14/1997
• Issued: 08/10/1999
• Est. Priority Date: 01/14/1997
• Status: Expired due to Fees

• Current Assignee: Molten Metal Technology Incorporated
• Original Assignee: Molten Metal Technology Incorporated
• Inventors: Everitt, David A., Stephenson, Michael J., Haas, Paul A.
• Primary Examiner(s): Tran, Hien
• Application Number:
  US08/783,512
• Time in Patent Office: 938 Days
• Field of Search: 422/159, 422/173-174, 422/198-199, 423/260-261, 423/253, 423/659, 588/19, 252/636, 366/146, 366/178.1, 366/178.2, 366/178.3, 48/86 R
• US Class Current: 422/159
• CPC Class Codes: B01J 12/02 for obtaining at least one reaction product which, at normal temperature, is in the solid state
• CPC Class Codes: B01J 19/26 Nozzle-type reactors, i.e. the distribution of the initial reactants within the reactor is effected by their introduction or injection through nozzles
• CPC Class Codes: B01J 2219/00099 the reactor being immersed in the heat exchange medium
• CPC Class Codes: B01J 2219/00119 Heat exchange inside a feeding nozzle or nozzle reactor
• CPC Class Codes: B01J 2219/00135 Electric resistance heaters
• CPC Class Codes: B01J 2219/00159 controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
• CPC Class Codes: B01J 8/1827 the fluidising gas being a reactant
• CPC Class Codes: C01G 43/01 Oxides; Hydroxides
• CPC Class Codes: C01G 43/025 Uranium dioxide

Abstract

A multicomponent fluid feed apparatus is disclosed that independently preheats and then mixes two or more fluid streams being introduced into a high temperature chemical reactor to promote more rigorous and complete reactions using assemblies of inert tubular elements and an integral mixing orifice plate. The design allows use of ceramic and speciality alloy materials for high temperature service with particularly corrosive halide feeds such as UF₆ and HF. Radiant heat transfer to the tubular elements from external means gives the necessary system high temperatures without excessive temperatures to cause material failure. Preheating of the gaseous reactants in a separate step prior to mixing and injecting the gaseous reactants into a high temperature chemical reactor was found to provide an improved thermal conversion of UF₆ to uranium oxides.

Claims

1. In combination with a high temperature chemical reactor for conversion of UF₆ to uranium oxide solids and HF including a reaction chamber, at least one feed port for receiving fluids to be reacted therein, a heating means in relationship to said reaction chamber for heating incoming fluids, and an exit port for removing reaction products from said reaction chamber, a multicomponent fluid feed apparatus, to the at least one feed port, for preheating and mixing at least two fluid streams being injected into said high temperature chemical reactor, said multicomponent fluid apparatus comprising:

an inner tubular flow member having first and second ends, said first end thereof disposed for receiving one of said at least two fluid streams to flow therethrough;

at least one outer tubular flow member having first and second ends concentrically disposed about and spaced from said inner tubular flow member to form at least one fluid stream flow annulus about said inner tubular member for separately receiving another one of said at least two fluid streams into said annulus for flow therethrough;

an orifice mixing plate sealably connected to said at least one outer tubular flow member at said second end thereof and having an opening therein in fluid communication with said second ends of said inner and said at least one outer tubular flow member, said opening being sufficiently tapered inwardly toward the concentric axis of said inner and outer tubular flow members to provide turbulent mixing of said fluid streams passing therethrough from the second ends of said inner and outer tubular flow members into said chemical reactor;

a heating means disposed about said at least one outer tubular member for heating all of said fluid streams flowing through said inner and outer tubular members to a selected temperature approximating the reaction temperature of the fluid streams in the high temperature reactor prior to mixing and injecting into said chemical reactor.

2. The combination as set forth in claim 1 wherein said at least one outer tubular flow member includes a plurality of outer tubular flow members concentrically disposed about said inner tubular flow member in a radially outward direction from the concentric axis of orientation of said tubular flow members to form a plurality of parallel flow annuli about said inner tubular flow member in fluid communication with said opening in said orifice mixing plate.

3. The combination as set forth in claim 1 wherein said chemical reactor is a thermal chemical reactor for conversion of UF₆ gas into uranium oxides and HF, further including a first fluid supply means for supplying a first fluid stream formed of UF₆ or a mixture of UF₆ and O₂ gases to one of said inner or outer tubular flow members and a second fluid supply means for supplying a second fluid stream formed of a combination of gases containing hydrogen selected from the group consisting of H₂, H₂ O, NH₃, and CH₄ and oxygen in a combined form selected from the group consisting of H₂ O and CO₂ to the other of said inner or outer tubular flow members.

4. The combination as set forth in claim 3 wherein said first fluid supply means is connected in fluid communication with said inner tubular member and said second fluid supply means is connected in fluid communication with said outer tubular member.

5. The combination as set forth in claim 4 wherein said tubular members are formed of materials that are essentially chemically inert to the respective streams of gases flowing therethrough at said selected preheating temperature.

6. The combination as set forth in claim 5 wherein said inner tubular member and said outer tubular members are formed of ceramic material suitable for corrosive gas operation at preheating temperatures in the range of from about 500 to 1000°

C.

7. The combination as set forth in claim 6 wherein said inner tubular member, said outer tubular members and said orifice plate are formed from a ceramic material selected from the group consisting of Al₂ O₃, CaF₂, yttria stabilized ZrO₂, LaB₆ and spinel (MgO·

Al₂ O₃).

8. The combination as set forth in claim 1, wherein said chemical reactor is a thermal chemical reactor for conversion of UF₆ gas into uranium oxides and HF wherein said at least one outer tubular flow member includes two outer tubular flow members, thereby forming first and second separate annular fluid flow channels about said inner tubular flow member and further including a first fluid supply means for supplying a first stream of gases formed of UF₆ to said inner tubular flow member, a second fluid supply means for supplying a second stream of gases formed of O₂ to said first annular fluid flow channel and a third fluid supply means for supplying a third stream of gases formed of a combination of gases containing hydrogen selected from the group consisting of H₂, H₂ O, NH₃, and CH₄ and oxygen in a combined form selected from the group consisting of H₂ O and CO₂ to said second annular fluid flow channel.

9. The combination as set forth in claim 1, wherein said chemical reactor is a thermal chemical reactor for conversion of UF₆ gas into uranium oxides and HF wherein said at least one outer tubular flow member includes two outer tubular flow members, thereby forming first and second separate annular fluid flow channels about said inner tubular flow member and further including a first fluid supply means for supplying a first stream of gases formed of a combination of gases containing hydrogen selected from the group consisting of H₂, H₂ O, NH₃, and CH₄ and oxygen in a combined form selected from the group consisting of H₂ O and CO₂ to said inner tubular flow member, a second fluid supply means for supplying a second stream of gases formed of UF₆ and O₂ to said first annular fluid flow channel and a third fluid supply means for supplying a third stream of gases formed of a combination of gases containing hydrogen selected from the group consisting of H₂, H₂ O, NH₃, and CH₄ and oxygen in a combined form selected from the group consisting of H₂ O and CO₂ to said second annular fluid flow channel.

10. The combination as set forth in claim 1, wherein said chemical reactor is a thermal chemical reactor for conversion of UF₆ gas into uranium oxides and HF wherein said at least one outer tubular flow member includes two outer tubular flow members, thereby forming first and second separate annular fluid flow channels about said inner tubular flow member and further including a first fluid supply means for supplying a first stream of gases formed of UF₆ to said inner tubular flow member, a second fluid supply means for supplying a second stream of gases formed of H₂ O to said first annular fluid flow channel and a third fluid supply means for supplying a third stream of gases formed of H₂ to said second annular fluid flow channel.

11. The combination as set forth in claim 1, wherein said heating means extends over substantially the entire length of said tubular flow members and wherein said tubular flow members are of a length sufficient to provide said selected temperature of said process fluids passing therethrough prior to injection into said reactor.

12. The combination as set forth in claim 1, wherein said second end of said inner tubular flow member extends into said tapered opening of said orifice mixing plate a selected distance depending on the selected location of mixing of said fluids passing through said tapered opening in said orifice mixing plate.

13. The combination as set forth in claim 1, wherein said at least one outer tubular flow member includes two outer tubular flow members, thereby forming first and second separate annular fluid flow channels about said inner tubular flow member.

14. The combination as set forth in claim 13, wherein said second ends of said inner tubular flow member and said first annular flow channel extends into said tapered opening of said orifice mixing plate a selected distance depending on the selected location of mixing of said fluids passing through said tapered opening in said orifice mixing plate.