Low current plasmatron fuel converter having enlarged volume discharges
A novel apparatus and method is disclosed for a plasmatron fuel converter (“plasmatron”) that efficiently uses electrical energy to produce hydrogen rich gas. The volume and shape of the plasma discharge is controlled by a fluid flow established in a plasma discharge volume. A plasmatron according to this invention produces a substantially large effective plasma discharge volume allowing for substantially greater volumetric efficiency in the initiation of chemical reactions within a volume of bulk fluid reactant flowing through the plasmatron.
1. A plasmatron fuel converter for producing a hydrogen rich gas, comprising:
a first electrode comprising an electrically conductive structure;
a second electrode disposed with respect to the first electrode as to create at least two boundaries of a plasma discharge volume;
a power supply connected to the first and second electrodes to provide voltage and current sufficient to generate a plasma discharge within the plasma discharge volume to initiate a reaction of an injected reactive mixture; and
means for establishing a fluid flow through the plasma discharge volume;
wherein the fluid flow continually stretches and extinguishes the plasma discharge generated within the plasma discharge volume; and
wherein the plasma discharge is continually and substantially reestablished randomly across the plasma discharge volume.
2. The plasmatron fuel converter of claim 1 wherein generation, extinction and reestablishment of the plasma discharge produces a quasi-continuous plasma discharge that is substantially equally distributed throughout the plasma discharge volume.
3. The plasmatron fuel converter of claim 2 wherein the quasi-continuous plasma discharge initiates chemical reactions substantially throughout the plasma discharge volume.
4. The plasmatron fuel converter of claim 3 wherein the chemical reactions are partial oxidation reactions selected for operation between stoichiometric partial oxidation and full combustion.
5. The plasmatron fuel converter of claim 1 wherein the plasma discharge is reestablished after extinction in a time of less than 100 nanoseconds.
6. The plasmatron fuel converter of claim 1 further comprising an injection mechanism for injecting said injected reactive mixture into said plasma discharge volume.
7. The plasmatron fuel converter of claim 6 wherein said injection mechanism comprises:
means for providing fuel;
means for providing air assist to mix with said fuel and to form a fuel/oxidant mixture; and
a nozzle for controlling injection of said fuel/oxidant mixture into said plasma discharge volume.
8. The plasmatron fuel converter of claim 6 wherein said injection mechanism and said fluid flow are adapted to provide an enlarged volumetric contact of said plasma discharge and said injected reactive mixture within said plasma discharge volume.
9. The plasmatron fuel converter of claim 1 wherein a flow direction of said injected reactive mixture is perpendicular to a flow direction of said fluid flow.
10. The plasmatron fuel converter of claim 1 wherein said injected reactive mixture and said fluid flow are the same flow.
11. The plasmatron fuel converter of claim 1 wherein the fluid flow comprises an oxidant.
12. The plasmatron fuel converter of claim 11 wherein the oxidant comprises air.
13. The plasmatron fuel converter of claim 11 wherein the oxidant comprises an exhaust gas containing free oxygen.
14. The plasmatron fuel converter of claim 1 wherein the fluid flow comprises a fuel/oxidant mixture.
15. The plasmatron fuel converter of claim 1 wherein said injected reactive mixture comprises a fuel/oxidant mixture.
16. The plasmatron fuel converter of claim 1 wherein said injected reactive mixture comprises fuel.
17. The plasmatron fuel converter of claim 1 wherein the current provided by the power supply is limited so as to prevent non-arcing-to-arc breakdown.
18. The plasmatron fuel converter of claim 1 wherein said power supply is an adjustable frequency power supply.
19. The plasmatron fuel converter of claim 18 wherein said adjustable frequency power supply is adapted to be adjusted from 100 Hz to 2 MHz.
20. The plasmatron fuel converter of claim 1 wherein said power supply provides voltage in the range of approximately 300 volts to 60 kilovolts and current in the range of approximately 10 milliamperes to 2 amperes to generate said plasma discharge within the plasma discharge volume.
21. The plasmatron fuel converter of claim 1 wherein said first electrode and said second electrode are hollow cylindrical electrodes disposed to form a channel containing the plasma discharge volume.
22. The plasmatron fuel converter of claim 1 wherein said first electrode and said second electrode are ring electrodes positioned in a vertical configuration.
23. The plasmatron fuel converter of claim 1 wherein said first electrode and said second electrode are rod electrodes positioned in a horizontal configuration.
24. The plasmatron fuel converter of claim 1 wherein said first electrode and said second electrode are cylinders positioned in a co-axial configuration.
25. The plasmatron fuel converter of claim 1 wherein the fluid flow is introduced upstream from the plasma discharge volume.
26. The plasmatron fuel converter of claim 1 wherein said fluid flow is adapted to provide an enlarged volumetric contact of said plasma discharge and said injected reactive mixture within said plasma discharge volume.
27. The plasmatron fuel converter of claim 1 further comprising:
a reactor having a reaction extension region adapted to receive an ignited reactive mixture from said plasma discharge volume.
28. The plasmatron fuel converter of claim 27 wherein the reactor is a metallic or ceramic cylinder.
29. The plasmatron fuel converter of claim 27 wherein an interior of the reactor is covered with thermal insulation.
30. The plasmatron fuel converter of claim 27 wherein an exterior of the reactor is covered with thermal insulation.
31. The plasmatron fuel converter of claim 27 wherein the reaction extension region contains a catalytic structure.
32. The plasmatron fuel converter of claim 31 wherein the catalytic structure is a metallic or ceramic honeycomb catalytic structure.
33. The plasmatron fuel converter of claim 31 wherein the catalytic structure is coated with one or more catalyst selected from the group consisting of ruthenium, rhodium, cobalt, iron, nickel, palladium, rhenium, osmium, and platinum.
34. The plasmatron fuel converter of claim 27 wherein a turbulizer is disposed within the reaction extension region to receive and deflect the ignited reactive mixture exiting the plasma discharge volume.
35. The plasmatron fuel converter of claim 27 further comprising:
a heat exchanger adapted to receive the hydrogen rich gas output from said reactor.
36. The plasmatron fuel converter of claim 35 wherein the heat exchanger is adapted to preheat the injected reactive mixture or said fluid flow.
37. The plasmatron fuel converter of claim 1 wherein the injected reactive mixture is selected for operation between stoichiometric partial oxidation and full oxidation.
38. The plasmatron fuel converter of claim 1 wherein an oxygen to carbon ratio of the injected reactive mixture is between 1.2 and 2.0.
39. The plasmatron fuel converter of claim 1 wherein said oxygen to carbon ratio of the reactive mixture is less than 1.2.
40. The plasmatron fuel converter of claim 1 wherein said plasmatron fuel converter operates at full combustion and wherein an output of said plasmatron fuel converter is a hot gas that is no longer hydrogen-rich.