Use of a chemically reactive plasma for thermal-chemical processes

• US 6,153,852 A
• Filed: 02/12/1999
• Issued: 11/28/2000
• Est. Priority Date: 02/12/1999
• Status: Expired due to Term

• Current Assignee: Sequoyah Finance One Limited
• Original Assignee: Thermal Conversion Corp.
• Inventors: Tuszewski, Michel G., Vavruska, John S., Ottinger, Robert S., Blutke, Andreas S., Bohn, Edward M.
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US09/249,657
• Time in Patent Office: 655 Days
• Field of Search: 219/121.59, 219/121.56, 219/121.55, 219/121.54, 219/121.52, 219/121.48, 219/121.43, 588/900, 588/901, 110/246, 110/346, 315/111.21, 315/111.51, 356/316
• US Class Current: 219/121.59
• CPC Class Codes: F23G 2204/201 Plasma
• CPC Class Codes: F23G 2209/102 Waste oil
• CPC Class Codes: F23G 2209/142 Halogen gases, e.g. silane
• CPC Class Codes: F23G 5/085 High-temperature heating means, e.g. plasma, for partly melting the waste
• CPC Class Codes: H05H 1/30 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/28 takes precedence

Abstract

A method for optimizing the efficiency of an inductively coupled plasma (ICP) torch by varying at least one of a plasma gas flow rate and a power level applied to energize the ICP torch, and method and apparatus for efficiently using a CO₂ feed as both a reactant and for generating a thermal plasma to produce high value chemical feed stocks, such as a synthesis gas or carbon monoxide from low value feedstocks, such as methane or carbon.

Claims

1. A method for maximizing an operating efficiency of an inductively coupled plasma (ICP) torch in which a plasma is generated, comprising the steps of:

(a) specifying a gaseous fluid used to generate the plasma;

(b) as a function of the gaseous fluid used to generate the plasma, modeling the ICP torch to determine an optimal flow rate of the gaseous fluid and an optimal power level for energizing an induction coil of the ICP torch to generate the plasma; and

(c) operating the ICP torch with the optimal flow rate of the gaseous fluid, and with the optimal power level applied to energize the induction coil of the ICP torch, so that the efficiency of the ICP torch is substantially maximized.

2. The method of claim 1, further comprising the step of monitoring a parameter that is a function of the operating efficiency of the ICP torch, to produce a signal indicative of said operating efficiency.

3. The method of claim 2, further comprising the step of employing said signal indicative of the operating efficiency of the ICP torch to adjust one of the power level applied to the induction coil of the ICP torch and the flow rate of the gaseous fluid, to further maximize the operating efficiency of the ICP torch.

4. The method of claim 3, further comprising the step of employing the signal indicative of the operating efficiency of the ICP torch to adjust the other of the power level applied to the induction coil of the ICP torch and the flow rate of the gaseous fluid, to still further maximize the operating efficiency of the ICP torch.

5. The method of claim 1, wherein the gaseous fluid comprises CO₂.

6. The method of claim 1, wherein the step of modeling is also based upon fixed parameters, including a length and radius of the ICP torch, and a frequency of power applied to operate the ICP torch.

7. A method for maximizing a product yield from a reaction vessel in which plasma gas from an inductively coupled plasma (ICP) torch reacts with a feedstock material in a reaction vessel, comprising the steps of:

(a) specifying a gaseous fluid used to generate the plasma;

(b) specifying a feedstock material;

(c) as a function of a gaseous fluid used to generate the plasma, modeling the ICP torch to determine an optimal flow rate of the gaseous fluid used to generate the plasma and an optimal power level for energizing an induction coil of the ICP torch to generate the plasma;

(d) operating the ICP torch with the optimal flow rate of the gaseous fluid and with the optimal power level applied to the induction coil of the ICP torch, so that the efficiency of the ICP torch is substantially maximized; and

(e) adjusting the flow rate of the feedstock material, so that the product yield is substantially maximized.

8. The method of claim 7, further comprising the steps of adding additional gaseous fluid to the reaction vessel in which the plasma is injected, said additional gaseous fluid being supplied as necessary to completely process all of the feedstock material.

9. The method of claim 7, further comprising the step of monitoring the product temperature and yield output from the reaction vessel to produce signals indicative of said product temperature and yield.

10. The method of claim 9, further comprising the step of adjusting at least one of the power level applied to the induction coil, the flow rate of the gaseous fluid into the ICP torch, and the flow rate of the gaseous fluid into the reaction vessel, to further optimize the yield of the thermal chemical conversion process in the reaction vessel.

11. The method of claim 10, further comprising the step of selectively giving priority either to optimizing the operation of the ICP torch or optimizing the product yield of the reaction vessel.

12. A method for using CO₂ both as a chemical reactant and for producing a thermal plasma to convert a feedstock material into a tailored gas composition within a reaction vessel, comprising the steps of:

(a) providing a plasma generator, a variable CO₂ gas supply system, a variable power supply connected to energize the plasma generator, a reaction vessel having an inlet adapted to receive a thermal plasma produced by said plasma generator and an outlet from which a product is output, and a variable feedstock supply system adapted to inject said feedstock material into said reaction vessel;

(b) supplying CO₂ to the plasma generator so that the plasma generator ionizes the CO₂ to produce ionized CO₂ that is the thermal plasma;

(c) injecting the ionized CO₂ from the plasma generator into the reaction vessel to simultaneously provide heat and a reactant; and

(d) injecting the feedstock material into the reaction vessel to react with the ionized CO₂, said ionized CO₂ thus serving both as the thermal plasma, which is a reaction heat source, and as a chemical reactant for processing the feedstock material.

13. The method of claim 12, wherein the variable CO₂ gas supply provides substantially pure CO₂.

14. The method of claim 12, wherein the variable CO₂ gas supply provides a CO₂ rich gas.

15. The method of claim 12, wherein the feedstock material comprises an organic material.

16. The method of claim 15, wherein the feedstock material comprises methane.

17. The method of claim 15, wherein the feedstock material comprises carbon.

18. The method of claim 15, wherein the desired product comprises a synthesis gas.

19. The method of claim 18, further comprising the step of injecting steam into the reaction vessel to selectively vary a proportion of H₂ to CO in the synthesis gas produced.

20. The method of claim 18, further comprising the step of injecting steam into the plasma generator to selectively vary a proportion of H₂ to CO in the synthesis gas produced.

21. The method of claim 12, wherein the feedstock material comprises hydrogen.

22. The method of claim 12, wherein the feedstock material comprises a solid, particulate form.

23. The method of claim 12, wherein the feedstock material comprises a liquid before being injected into the reaction vessel.

24. The method of claim 12, wherein the feedstock material comprises a gas before being injected into the reaction vessel.

25. The method of claim 12, wherein the feedstock material comprises any combination of a solid, a liquid, and a gas before being injected into the reaction vessel.

26. The method of claim 12, further comprising the step of mixing a portion of said feedstock material with said CO₂ before ionization of the CO₂ by the plasma generator.

27. The method of claim 12, further comprising the step of mixing substantially all of said feedstock material with the CO₂ before ionization of the CO₂ by the plasma generator.

28. The method of claim 12, further comprising the step of injecting a portion of the CO₂ into the reaction vessel as a non-ionized reactant, said portion of the CO₂ being supplied in sufficient quantity to completely react said feedstock material.

29. The method of claim 12, further comprising the step of providing a controller coupled to and able to selectively control at least one of the variable CO₂ gas supply system, the variable power supply, and the variable feedstock supply system.

30. The method of claim 29, wherein the plasma generator is an inductively coupled plasma (ICP) torch.

31. The method of claim 30, further comprising the steps of:

(a) modeling the ICP torch to determine an optimal CO₂ plasma gas flow rate and power level to maximize an efficiency of the ICP torch; and

(b) with the controller, controlling said variable CO₂ gas supply system to provide said optimal CO₂ plasma gas flow rate, and controlling said variable power supply to provide said optimum power level to energize the ICP torch.

32. The method of claim 30, wherein the controller includes a processor, comprising the steps of:

(a) monitoring the ICP torch efficiency, producing a signal indicative of the ICP torch efficiency that is conveyed to the processor; and

(b) automatically varying said CO₂ plasma gas flow rate and said power level with the processor as a function of the signal, to maintain an optimal torch efficiency.

33. The method of claim 31, further comprising the steps of:

(a) injecting a portion of the CO₂ into the reaction vessel, in a non-ionized state;

(b) as a function of a reaction between the ionized CO₂ produced by the ICP torch, the feedstock material, and any non-ionized CO₂ gas injected into the reaction vessel, determining desired flow rates for the feedstock material and any non-ionized CO₂ gas flow into the reaction vessel required to substantially maximize a product yield from the reaction vessel; and

(c) controlling said feedstock material and a flow of said non-ionized CO₂ injected into the reaction vessel with the controller to provide the desired flow rates, so that the product yield from the reaction vessel is maximized.

34. The method of claim 30, wherein the controller includes a processor, further comprising the steps of:

(a) monitoring the product yield from the reaction vessel, producing a signal indicative of the product yield; and

(b) providing a software program to control the processor so that it automatically varies the feedstock material feed rate and the non-ionized CO₂ gas flow rate into the reaction vessel to optimize product yield based on the signal.

35. The method of claim 34, further comprising the steps of:

(a) as a function of the reaction between the ionized CO₂, the organic feed, and any non-ionized CO₂ gas injected into the reaction vessel, determining an optimal CO₂ plasma gas flow rate and an optimum power level that substantially maximizes a product yield from the reaction vessel; and

(b) providing a software program for execution by the processor that causes it to monitor and automatically vary the CO₂ gas flow rate and power level so as to substantially maximize the product yield from the reaction vessel, even if CO₂ gas flow rate and power level used by the processor result in a non optimal ICP torch efficiency.

36. The method of claim 35, further comprising the step of selectively giving priority to the processor for optimizing either the operating efficiency of the ICP torch, or the product yield from the reaction vessel.

37. Apparatus for converting a feedstock material into a tailored gas composition using CO₂ as both a chemical reactant with the feedstock material, and for producing a thermal plasma in a reaction vessel, comprising:

(a) a plasma generator capable of sustained production of a plasma, said plasma generator having an inlet port, an outlet port, and a heat sink that maintains an internal surface of the plasma generator below a predetermined maximum temperature, said plasma generator being connected to a variable power supply to energize the plasma generator;

(b) a variable CO₂ gas supply system that provides CO₂ gas to be ionized by the plasma generator, producing ionized CO₂ for the thermal plasma;

(c) a reaction vessel coupled to the outlet port of the plasma generator to receive the thermal plasma, said reaction vessel containing at least one injection port through which a feedstock material is injected into the thermal plasma, said at least one injection port being connected to a variable feedstock supply system; and

(d) an outlet port from said reaction vessel adapted to convey a high temperature product of a reaction between the feedstock material and the ionized CO₂ from the reaction vessel, said product being produced by a reaction between the ionized CO₂ and the feedstock material using energy from the thermal plasma to promote the reaction.

38. The apparatus of claim 37, wherein said at least one injection port into the reaction vessel is configured to produce a tangential injection pattern.

39. The apparatus of claim 38, wherein said at least one injection port into the reaction vessel further comprises at least one additional injection port, said at least one additional injection port being configured to tangentially inject a reactant in a substantially opposing direction to said tangential injection pattern produced by said at least one injection port, such that the reactant from said at least one injection port intersects the reactant from said at least one additional injection port, thereby promoting turbulence in the reaction vessel.

40. The apparatus of claim 37, wherein said at least one injection port into the reaction vessel is configured to produce a radial injection pattern.

41. The apparatus of claim 37, wherein said at least one injection port into the reaction vessel is configured to produce a countercurrent injection pattern.

42. The apparatus of claim 37, further comprising an acid removal system connected to the outlet port of the reaction vessel, to remove an acid contamination from the tailored gas composition.

43. The apparatus of claim 37, further comprising a variable steam supply system adapted to inject steam into the reaction vessel, to selectively vary a proportion of CO to H₂ in the tailored gas composition.

44. The apparatus of claim 43, further comprising a heat exchanger adapted to use heat from the tailored gas composition exiting said reaction vessel to preheat at least one of said CO₂, said feedstock material, and said steam.

45. The apparatus of claim 37, wherein said feedstock material is mixed with said CO₂ gas and supplied to the inlet port of said plasma generator.

46. The apparatus of claim 37, further comprising a member disposed in said reaction vessel to produce turbulence, said turbulence promoting thorough mixing of said feedstock material and said ionized CO₂.

47. The apparatus of claim 46, wherein the feedstock material is injected into the reaction vessel at an area of said turbulence caused by said member.

48. The apparatus of claim 37, wherein the plasma generator is an inductively coupled plasma (ICP) torch and the power supply is adapted to provide an alternating current to energize the ICP torch.

49. The apparatus of claim 48, further comprising a plurality of ICP torches connected to said reaction vessel, each of said plurality of ICP torches being coupled to the variable power supply and in fluid communication with the variable CO₂ gas supply system, to produce the ionized CO₂.

50. The apparatus of claim 49, further comprising a controller connected to selectively control the variable CO₂ gas supply system, the power supply, and the feedstock supply system.

51. The apparatus of claim 50, further comprising at least one sensor disposed at said outlet port from said reaction vessel to determine a product yield, said sensor producing a signal indicative of the product yield that is input to said controller.

52. The apparatus of claim 51, further comprising a temperature sensor disposed at said outlet port to determine a product temperature, said temperature sensor producing a signal indicative of the product temperature that is input to said controller.

53. The apparatus of claim 52, further comprising a temperature sensor disposed at said heat sink to monitor a temperature of said heat sink and produce a signal indicative thereof that is input to said controller, said temperature and a level of current supplied to energize said ICP torch by said power supply being used by the controller to determine said ICP torch efficiency.

54. The apparatus of claim 53, wherein said controller includes a processor programmed to maximize ICP torch efficiency by selectively varying at least one of the gas flow rate from said CO₂ gas supply system to the ICP torch and the level of current supplied to energize said ICP torch by said power supply.

55. The apparatus of claim 54, wherein said variable CO₂ gas supply system also injects a non-ionized CO₂ gas flow into said reaction vessel, said processor being programmed to maximize reaction efficiency by selectively varying at least one of said CO₂ gas flow rate into the ICP torch, said current supplied by the power supply to energize the ICP torch, said non-ionized CO₂ gas flow, and said organic feed provided by said organic feed supply system.

56. The apparatus of claim 55, wherein the processor is programmed to allow an operator to selectively set a priority on either maximizing the ICP torch efficiency, or maximizing the product yield from the reaction vessel, or maximizing a different selected parameter.