US3445191A - Arc heater apparatus for chemical processing - Google Patents

Description

y 1969 A. M. BRUNING ET AL 3,445,191

ARC HEATER APPARATUS FOR CHEMICAL PROCESSING Filed July 14, 1965 3,445,191 ARC HEATER APPARATUS FOR CHEMICAL PROCESSING Armin M. Bruning, Franklin Township, Export, and Peter F. Kienast, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed July 14, 1965, Ser. No. 471,914 Int. Cl. Hb 7/18 US. Cl. 23-277 10 Claims ABSTRACT OF THE DISCLOSURE An arc heater for chemical processing has a pair of axially spaced annular electrodes producing an axially extending arc therebetween. Field coils in the electrodes set up a magnetic field which causes the arc to move substantially continuously in an annular path around the electrodes. Means is provided for admitting a process gas at a large number of peripherally spaced points whereby the process gas passes through the arc path and thence into the arc chamber and downstream toward the nozzle. Process gas may be admitted at a number of additional positions axially spaced along the arc heater, always at a large number of peripherally spaced points. A quenching gas may be admit-ted through the arc path but at a position downstream of where the process gas is admitted: a quenching gas may be admitted through a central aperture in the plug closing the upstream end of the arc chamber at a position actually upstream of the position where the process gas is admitted, but the quenching gas moves downstream before mixing occurs. Very rapid quenching in a time of the order of a fraction of a microsecond is obtainable. Additionally, fluid may be introduced at axially spaced positions at a plurality of peripherally spaced points to freeze the recombination product and prevent further undesired chemical reactions.

This invention relates to are heater apparatus for chemical processing, and more particularly to such are heater apparatus having improved means for the introduction of reactant and quenching materials.

Chemical reactions promoted by thermal energy have in the past successfully employed an arc source for heating or pyrolyzing a process gas. In many chemical reactions there is need for quenching immediately after the reactant has been heated by the are or other means. Immediate quenching enables the recovery of specific chemical products prior to their recombination or dissociation into the often times more stable but less desirable byproducts. Some reactions yield best results with quenching taking place only microseconds to milliseconds after heating, thus requiring close proximity between the quench zone and heating zone.

In the past no satisfactory way has been found of obtaining an immediate quench. For example, in British Patent 938,823 issued to E. I. du Pont de 'Nemours & Company, the first quenching material is introduced a considerable distance from the arc zone, representing a considerable elapsed time.

Our apparatus overcomes the limitations of the prior art and provides for immediate quenching, by the immediate introduction of a quenching material either gaseous or liquid, or both, within microseconds, or even a fraction of a microsecond, after the process gas is decomposed. Further, the improved apparatus of our invention provides for introducing either a gaseous or liquid quench or both at various time intervals after the decomposition takes place, as required by some particular chemical reaction or process to be carried out.

3,445,191 Patented May 20, 1969 This application is related to the copending application of C. Hirayama et al. for Method and Equipment for the Pyrolysis and Synthesis of Hydrocarbons and Other Gases and Arc Heater Apparatus for Use Therein, S.N. 446,012, filed Apr. 6, 1965, now issued Patent 3,389,189; the application of P. F. Kienast et al. for Arc Heater Apparatus for Chemical Processing, S.N. 471,-914, filed July 14, 1965; the application of A. M. Bruning et al. for Cross Flow Arc Heater Apparatus and Process for the Synthesis of Carbon, Acetylene, and Other Gases, S.N. 507,345, filed Nov 12, 1965; the application of D. A. Maniero et al. for Direct Conversion Chemical Processing Arc Heater, S.N. 527,789, filed Feb. 16, 1966 now issued Patent 3,284,782; and the application of D. A. Maniero et al. for Process for Hydrogen Cyanide and Acetylene Production in an Arc Heater Having a Rotating Arc, S.N. 657,867, filed Aug. 2, 1967, all of the aboveidentified applications being assigned to the assignee of the instant invention.

In summary, our apparatus includes means forming an arc chamber in which two substantially cylindrical electrodes spaced from each other have an arc therebetween, the two electrodes having magnetic field producing coils disposed therein for producing a magnetic field transverse to the arc path which causes the arc to move substantially continuously around the arcing surfaces of the electrodes. One end of the substantially cylindrical arcing chamber is closed by a plug or closure member, and process gas is introduced into a substantially cylindrical passageway between the plug and the inner wall of the arcing chamber. A first quenching gas or liquid may be introduced through the aforementioned plug which has a passageway therein. In addition, a ring or heat shield member spacing the aforementioned two electrodes has annular header means therein, with means for introducing a quenching material, either gaseous or liquid, through a plurality of spaced apertures around the entire periphery of the ring or spacing heat shield member. An additional and similar ring or spacer member is disposed downstream of the downstream electrode, between the downstream electrode and the nozzle, and this last-named spacer ring also has header means therein, and a plurality of apertures therearound communicating with the header means for introducing a spray or reactant into the gas as it moves past the downstream electrode toward the nozzle. Furthermore, the nozzle of the electrode has a plurality of apertures in the inner wall thereof communicating with a fluid passageway therein, for spraying a quenching material, which may be gaseous or liquid, into the process gas as it is exhausted from the nozzle. An extension to the nozzle provides for further spraying a cooling or quenching fluid into the heated gas at a fourth downstream position representing a longer elapsed time interval between the heating of the gas and the introduction of the last-named quenching fluid. In addition to process gas being introduced around the aforementioned plug which closes one end of the arcing chamber, header means are provided for introducing gas on both sides of the spacer member between the two electrodes, and on both sides of the spacer member between the downstream electrode and the nozzle, so that these last-named four annular gas headers, with a plurality of spaced bores communicating with the interior of the chamber at spaced intervals around the entire peripheries thereof, provide ample means for introducing a fluid or gaseous quenching material or materials into the chamber at a number of position with respect to the gas heating or pyrolyzing zone. In effect then a gaseous quench or a fluid quench may be introduced into the process gas after heating at almost any desired instant, and with any desired elapsed time interval be tween the decomposition of the gas and the introduction of the quench.

Accordingly a primary object of the invention is to provide new and improved arc heater apparatus especially suitable for chemical processing.

Another object is to provide new and improved arc heater apparatus having new and improved means for introducing reactant and quenching materials.

These and other objects will become more clearly apparent after a study of the following specification, when studied in connection with the accompanying drawing, in which the single figure thereof represents our invention according to the preferred embodiment thereof.

Referring now to the drawing for a more detailed understanding of the invention, there is shown an arc heater generally designated 9 which is seen to be substantially cylindrical in shape and to have an outer wall portion formed of a cylindrical upstream electrode member generally designated 11, a ring member generally designated 12, a downstream electrode generally designated 13, and an additional ring member generally designated 14 spacing the downstream electrode 13 from a downstream closure and nozzle member generally designated 15, all of these enclosing an arc chamber generally designated 10. An additional nozzle generally designated 16 is attached in a form or manner to extend the length of the nozzle and the quenching or cooling exit passageway therethrough. The other end of the arc chamber is closed by a closure member generally designated 17 which as seen is adapted to be fluid cooled from headers 171 and 176 and which also has a passageway 18 therethrough for the introduction of a quenching material into the arc chamber 10. Arc 21 is seen taking place in the chamber 10 between electrodes 11 and 13. Means for bringing a current to the arc heater apparatus generally designated 9 is securely connected to electrodes 11 and 13 and is symbolized by leads 23 and 24, which it is understood may be connected to a suitable source of direct current potential, not shown, or to a source of single phase alternating current potential, not shown for convenience of illustration.

As previously stated, the apparatus is especially constructed to permit the introduction of a reactant or process gas, and also to permit the introduction at various points and at various times in the movement of the process gas through the arc heater of other reactants or quenching materials which may be either gaseous or fluid. To this end an annular or cylindrical space 25 exists between the outer wall of the closure member 17 and the inner wall of the electrode generally designated 11. In the electrode 11 there is a fluid or gas header which is annular in shape, the header being shown at 26, having a gas inlet 27 and having a plurality of spaced radial passageways, two of these being shown at 28 and 29, communicating between heater 26 and annular space 25. The section of the arc chamber wall or electrode generally designated 11 is seen to comprise generally speaking two portions, an outer portion 31 which may be of for example, steel, and may be of ferromagnetic material, and an inner portion 32 of, for example copper. The copper portion 32 is seen to have a thin wall portion 33 adjacent the arc chamber 10, and it is seen that directly behind the thin wall portion 33 is a cylindrical passage 35 shaped generally to the contour of the wall portion 32. The passage 35, which as beforementioned is cylindrical in shape, may extend around the entire circumference of the wall portion, and is provided for the flow of cooling water or other fluid which may enter the annular or ring shaped water passage or water header 37 by way of inlet conduit 38 and exit from the annular ring-shaped water passage 36 by way of exit conduit 39. The outer chamber wall portion 31 is seen to have sealing means such as O-rings at 41, 42, 43 and 44 for providing seals between the outer section 31 and the inner section 32. Disposed in an annular recess 45 in portion 32 is a field coil 46 provided for assisting in setting up a magnetic field transverse to the arc path and to the path of current flow for providing a force on the arc in such a direction as to cause the arc to move substantially continuously in an annular path on the electrodes 11 and 13. As will be readily understood by those skilled in the art, it is necessary to continually move the arc to prevent the intensely hot are spot from burning a hole in the electrode with resulting escape of fluid into the arc chamber and possible destruction of the electrode, or explosion within the chamber. It is seen that the outer wall contour of wall portion 33 comes to a peak at 48, overhanging the annular space 120 which separates the ring generally designated 12 from the cylindrical portion 11 on the adjacent side thereof. This annular peak 48 is provided to ensure optical baflling for the insulating ring member 113 and for O-ring 30, so that direct radiation from the arc 21 in the arc chamber 10, and direct radia tion from heated gas in the vicinity of the are 21, do not fall upon the insulating member 113 or the O-ring 30. Wall surface 50 is rounded and conforms very closely to the path of the magnetic flux in this area.

As seen from the figure, the aforementioned annular or ring-shaped passageway exists between the wall of ring 12 and the adjacent wall of cylindrical electrode 11. Near this annular passageway 120 and within the electrode 11 there is disposed an annular fluid header 121, having an inlet 122, and having a plurality of passageways at spaced intervals around the entire electrode communicating between the header 121 and the ring-shaped passageway 120, two of these communicating passageways being shown at 123 and 124. This arrangement permits the introduction of gas, which may be either a portion of the process or reactant gas, or may be gas deliberately introduced to quench or cool the heated gas in the arc chamber.

The electrode member generally designated 11 is spaced from and electrically insulated from the ring member 12 by an insulating disc 19 which terminates at its inner edge in the aforementioned O-ring 30.

The aforementioned ring member 12 which may also serve as a heat shield, may include two sections composed of different materials. The inner ring portion 214 may be composed of copper; the outer ring portion 212 may have an annular passageway 215 therearound for the passage of a cooling fluid, for example water, in two substantially semicircular paths between a water inlet 221 and a water outlet 222. O-rings 217 and 218 provide a seal for the fluid in passageway 215. A series of annular groove-like passageways or fingers extend from the passageway 215 toward the surface of ring portion 214 which faces the arc chamber 10, three of these annular fingers being shown at 231, 232 and 233, each of the annular fingers having a plurality of spaced bores extending therefrom through the inner wall of the chamber around the entire periphery of ring member 12, the bores of finger 231 being designated 234, those of annular finger 232 being designated 235, and those of finger 233 being designated 236.

Spaced from the ring member generally designated 12 is the aforementioned downstream electrode generally designated 13, the electrode 13 being spaced from and electrically insulated from the ring 12 by an insulating disc 20 terminating in an O-ring 22. Disposed between the O-ring 22 and the annular or ring-shaped passageway 119 between the wall of ring 12 and the adjacent wall of electrode 13 is an insulating member 114 preferably composed of a highly heat resistant ceramic, to optically shield the O-ring 22 from direct or reflected radiation. The electrode 13 is generally similar to the aforementioned electrode 11 and includes an outer portion 51 which may be steel or ferromagnetic material, and an inner portion 52 with a thin wall portion 53. Adjacent the wall portion 53 is a cylindrical cooling passage 55, having an inlet or header at 56 connected to inlet conduit 58, and an outlet or header at 57 connected to outlet conduit 59. Sealing O-rings 61 and 62 are provided, and a field coil 66 is provided as shown in recess 65. The wall portion 53 also has a peak portion 68 for providing optical bafiling for the insulating member 114 and O-ring 22. Wall surface 60 is curved to the curvature of the magnetic field from coil 66.

An annular gas header 237 in the electrode 13 has a gas inlet 23S and a plurality of passageways from the header communicating with the annular passageway 119 between ring 12 and electrode 13 for bringing gas into the passageway at a plurality of points at spaced intervals around the entire inner wall of the arc heater, this last named gas being either a process gas or a quenching gas. Two of these passageways are shown at 239 and 240. On the other side of the electrode 13 is an additional gas header 241 having a gas inlet 242 and a plurality of passageways therefrom at spaced intervals around the periphery of the electrode communicating with the annular space 246 between the electrode 13 and the adjacent ring 14, two of the aforementioned passageways being shown at 243 and 244.

Disposed adjacent the aforementioned downstream electrode 13, and between the downstream electrode 13 and the aforementioned closure and nozzle member generally designated 15, is an additional ring member generally designated 14, which is substantially similar to the previously described ring 12. Ring 14 is spaced from and electrically insulated from the electrode 13 by insulating disc 192 terminating in an O-ring 193. Between the O-ring 193 and located in the aforementioned annular space 246 is a ceramic ring of highly heatresistant material 194. As previously stated, the ring member 14, which may also serve as a heat shield, has an outer portion 195 and an inner portion 196 composed of copper or other highly heat conductive material, the outer portion 195 having an annular fluid header or passageway 197 therein for providing two substantially semicircular paths for a fluid through the ring, the fluid header 197 communicating with a fluid inlet 198 and a substantially oppositely disposed fluid outlet 199. O-rings 201 and 202 provide sealing between the two portions of the ring, and the annular fluid header 197 has three annular fingers 203, 204, 205, extending therefrom, each of the fingers or annular passageways having a plurality of bores therefrom to the inside of the arc chamber, the bores passing through the narrow wall portion, the bores of finger 203 being designated 206, those of finger or annular passageway 204 being designated 207, and the bores of passageway 205 being designated 208.

The aforementioned closure or nozzle member 15 is generally disc-shaped, with a nozzle opening 140 substantially centrally disposed therein, member 15 being spaced from and electrically insulated from the aforementioned ring 14 by insulating disc 141 terminating in O-ring 142 with a ceramic annular wafer 143 disposed in the space 144 between the wall of ring 14 and the adjacent wall of member 15. Member 15 has an annular gas header 146 with a gas inlet thereto 147 and a plurality of small passageways communicating between the annular gas header 146 and the space 144, two of these passageways being shown at 148 and 149. An annular fluid header 151 with a fluid inlet 152 communicates by way of substantially U-shaped or cylindrical passageway 153 with a fluid outlet header, not shown for convenience of illustration, the fluid outlet header being located in the nozzle portion generally designated 16. Cylindrical passageway 153 has a plurality of spaced bores therefrom in generally ring-shaped form extending through the wall of the nozzle so that a quenching fluid may be introduced into gas passing through the nozzle. These bores are shown at 155 and may be in the pattern of axially spaced circles with a plurality of bores at spaced intervals around each circular position.

The aforementioned nozzle 16 forms in effect a continuation of the nozzle passageway 140, and includes in addition to the generally cylindrical portion 157 a flange 158 and includes an annular groove 159 for the O-ring 160.

A passageway 162 through the aforementioned electrode generally designated 11 is provided for bringing leads to the aforementioned field coil 46; it will be understood that a similar passageway, not shown because it is not in the particular cross-sectional plane selected for illustration, is provided for the aforementioned field coil 66, or leads may be made internally between the coils if desired. The leads to the coil 46 are shown at 163.

The aforementioned closure member for the lefthand end of the arc chamber 10, as seen in the figure, is generally designated 17 and comprises a flange portion 166 electrically insulated from electrode 11 by an insulating disc 167 terminating in O-ring 168; the plug member generally designated 17 as aforementioned has an axially extending passageway 18 with a flaring throat portion 169 on the inner end thereof, and is provided for bringing a quenching material, preferably a gas, into the arcing chamber very close to the exit of the anular passageway 25 through which, as aforementioned, the process gas is admitted to the chamber. As a result of passageway 18 and throat portion 169, a very short time interval of the order of a microsecond or perhaps less may elapse between the time that the process gas is pyrolyzed by the are 21, and the time that a quenching fluid or quenching gas is introduced therein, when this is desirable to obtain the desired recombination product in accordance with the process and chemicals employed. Plug 17 contains two annular water headers, one of these being shown at 171 communicating with inlet passageway 172, the water header 171 connecting with a cylindrical shaped fluid passageway 173 which extends near the surface 174 of the plug which is exposed to radiation from the arc, thereby providing for cooling the same and transferring heat flux away from the same; thence the water flows down cylindrical passageway 175 to annular water header 176 communicating with water outlet 177.

It will be understood that any convenient means, not shown for convenience of illustration, may be pro- -vided for applying clamping forces between the outer surface of the flange 166 and the flange 158 of nozzle 16 to clamp these two together and thereby apply clamping forces to the remainder of the structure. In addition, insulated clamping rings may be mounted against the outer side surface of electrode 11, and the outside annular surface of nozzle member 15, and clamped by insulating bolts or other convenient means, to hold the electrode 11, ring 12, electrode 13, ring 14 and nozzle member 15 securely together.

In the operation of the above described apparatus, process gas, for example a hydrocarbon, for example methane, may be introduced through gas inlet 27, flowing into annular gas header 26 which communicates by a number of radially extending passageways 29 with the cylindrical passageway 25, gas exiting from the cylindrical passageway 25 very near the are 21 and immediately or substantially immediately passing into the heating zone of the arc. From the general area of the are, represented by the disc-like zone traversed by the arc 21 as it moves in a circular path between the electrodes, gas flows downstream past the downstream electrode 13, past the downstream ring or heat shield 14, into the central aperture of the nozzle, and thence out the exit end of the nozzle, not shown for convenience of illustration. If it is desired to quench or cool the gas heated and dissociated by the are 21 by introducing and adding another, cooler gas to cool the entire mixture to a temperature at which some desired product is in a stable equilibrium in proportions of substantial magnitude, then the cooling gas may be introduced into the aforementioned passageway 18, or the cooling gas may be introduced through gas inlet 122 to gas header 121 and thence exit through many spaced radially extending oblique passageways 123 and 124, coming out near the peak 48 of electrode 11 and mixing with the gas heated by the are. In like manner,

gas may enter the inlet 238, pass around annular gas header 237 and out the plurality of spaced passageways 239 and 240, exiting into the gas heated zone near the aforementioned peak 168, this last named gas being introduced only a very small interval of time, in the order of a microsecond or perhaps less, after the gas introduced through passageway 120. The gas then moves further downstream in the chamber of the arc heater 10. As previously stated, the apparatus is constructed to accommodate the introduction of a fluid or liquid quench if desired, and this may be done through the passageways 231, 232 and 233 communicating with fluid header 215 and with the aforementioned holes 234, 235 and 236, bringing the fluid into the chamber at spaced intervals around the entire inner wall of the chamber.

From the area of the arc zone itself, the gas passes in a right-hand direction through the chamber 10, past the aforementioned holes 206, 207 and 208 where a further fluid quenching material may be introduced into the gas by way of inlet 198, and thence through the nozzle opening 140 where still a further fluid may be introduced by holes 155. It is also seen that there are additional places for introducing a quenching gas, for example by way of inlet 242, header 241 and passageways 243 and 244, and a short time interval later by way of gas inlet 147, header 146 and spaced passageways 148 and 149. In effect then substantially any time interval may be selected to introduce the quench gas and/or fluid into the process gas, depending upon the particular chemical composition of the gas and the particular speed at which an equilibrium condition is caused to exist at which the desired product is present in substantial proportion.

If desired, where it is not necessary or desirable to introduce a fluid quenching material into the chamber 10, the passageways 234, 235 and 236 communicating with annular fingers or passageways 231, 232 and 233 may be eliminated, as may be the bores or passageways 206, 207 and 208 communicating with fingers 203, 204 and 205, in which case fluid flowing in the annular headers 215 and 197 serves merely to cool the portions of the rings which face the intensely hot gases and radiation of the arc chamber 10.

If desired, separate inlet and outlet headers may be provided for the two portions of the nozzle, so that individual control can be maintained over the gas or fluid coming through holes 155 in the member 15, and individual control may be maintained over the gas or fluid coming into the nozzle through the corresponding holes in the nozzle generally designated 16.

The axially extending passageway 18 in member 17 may be omitted where it is not desired to introduce gas through the plug, or as will be readily understood, the left-hand end of the passageway 18 may be closed by suitable closure means, not shown for convenience of illustration, when it is not desired to use the passageway.

In like manner any of the inlets or outlets 27, 39, 38, 122, 221, 222, 238, 58, 59, 242, 199, 198, 147 or 152 may be closed or plugged by any suitable means, where it is not desired to use the particular passageways for the injection of a process or quenching material, be it a gas or a liquid.

There has been provided, then, apparatus well suited to accomplish the objects of our invention, which were to provide arc heater apparatus having means for introducing a quench either gaseous or liquid or both, at substantially any selected time interval extending from a fraction of a microsecond to a few milliseconds after the process gas is heated by the electric are 21 to a temperature at which dissociation takes place.

Whereas we have shown and described our invention with respect to apparatus which gives satisfactory results, it should be understood that changes may be made and equivalents substituted without departing from the spirit and scope of the invention.

We claim as our invention:

1. Arc heater apparatus for chemical processing having a pyrolyzing zone in which a selected process gas is decomposed at a variable temperature in accordance with variations in the are power and the mass flow rate of gas through the arc heater, and in which the pyrolyzed gas must be quenched in a predetermined time which varies with different process gases, to a predetermined temperature which varies for different desired recombination products comprising, in combination, means forming an arc chamber, the chamber forming means including first and second spaced annular electrodes each having passageways therein near the surface adjacent the arc chamber for the flow of cooling fluid, the second electrode being the downstream electrode, means connected to the first and second electrodes for producing and sustaining an arc therebetween, means for producing a magnetic field in the arc chamber of a magnitude and direction to cause the are between the first and second electrodes to move substantially continuously in an annular path around the first and second electrodes, closure means for the end of the chamber adjacent the first electrode and having a passageway therein for the flow of cooling fluid, the closure means having a passageway extending therethrough for bringing a quenching gas into the chamber, means forming a cylindrical passageway around the closure means for admitting a process gas into the chamber in a cylindrical path of substantially the same diameter as the cylindrical path of the arc, the process gas entering the chamber near the arc, a first ring member disposed between the first and second electrodes and having an annular passageway therein for the flow of cooling fluid, an exhaust nozzle member forming an exhaust vent and having a generally cylindrical passageway therein for the flow of cooling fluid, and a second ring member disposed between the second electrode and the nozzle member and having an annular passageway therein for the flow of cooling fluid, the first ring member having axially and peripherally spaced holes therein communicating with the cooling fluid passageway therein for injecting a quenching fluid into the gas in the chamber over an area substantially coextensive with that defined by the cylindrical arc path, the second ring member having axially and peripherally spaced holes therein communicating with the cooling fluid passageway therein for injecting an additional fluid into the gas in the chamber adjacent the second ring member, the nozzle member having axially and peripherally spaced holes therein communicating with the cooling fluid passageway therein for injecting a further quenching fluid into the gas mixture as it passes through the exhaust vent.

2. Are heater apparatus for chemical processing having a pyrolyzing zone in which a selected process gas is decomposed at a variable temperature in accordance with variations in the are power and the mass flow rate of gas through the arc heater, and in which the pyrolyzed gas must be quenched in a predetermined time which varies with different process gases to a predetermined temperature which varies with different desired recombination products comprising in combination, means forming an arc chamber, only two electrodes consisting of first and second spaced annular electrodes disposed in the arc chamber, the second electrode being the downstream electrode, means for producing and sustaining an are between the first and second electrodes, means for causing the arc to move substantially continuously in an annular path around and between the first and second electrodes, means for introducing a process gas into the arc chamber in a substantially cylindrical path upstream of the first electrode and near the annular arc path, said are pyrolyzing the process gas, means for introducing a quenching gas into the chamber upstream of the first electrode but at a position farther from the annular arc path than that at which the process gas is introduced, the quenching gas acting to cool the pyrolyzed gas a short time interval of the order of a microsecond after pyrolysis takes place, and nozzle exhaust means for the arc chamber.

3. Arc heater apparatus for chemical processing having a pyrolyzing zone in which a selected process gas is decomposed at a variable temperature in accordance with variations in the are power and the mass flow rate of gas through the arc heater, and in which the pyrolyzed gas must be quenched in a predetermined time which varies with different process gases to a predetermined temperature which varies for different desired recombination products comprising, in combination, means forming an arc chamber, first and second spaced annular electrodes disposed in the chamber, means for producing an arc between the first and second electrodes, means for causing the arc to move in a substantially annular closed path substantially continuously around and between the first and second electrodes, the second electrode being the downstream electrode, nozzle means disposed near the second electrode, means for introducing a process gas into the chamber near the first electrode, means for introducing a quenching gas into the chamber near the first electrode but downstream of the position whereat the process gas in introduced, means for introducing a quenching fluid into the chamber between the first and second electrodes, and means for introducing an additional quenching fluid into the gas mixture as it passes through the nozzle means.

4. Arc heater apparatus for chemical processing having a pyrolyzing zone in which a selected process gas is decomposed at a variable temperature in accordance with variations in the are power and the mass flow rate of gas through the arc heater, and in which the pyrolyzed gas must be quenched in a predetermined time which varies with different process gases to a predetermined temperature which varies for different desired recombination products comprising, in combination, means forming an arc chamber, the means including first and second spaced annular electrodes partially defining the arc chamber, means for bringing a current to the first and second electrodes to produce and sustain an arc therebetween, the chamber forming means including magnetic field producing means for producing a magnetic field which causes the arc to move substantially continuously in a substantially annular path around and between the electrodes, the second electrode being the downstream electrode, first ring and fluid header means disposed between the first and second electrodes, nozzle means including a nozzle opening, second ring and fluid header means disposed between .the second electrode and the nozzle means, plug means at the end of the chamber opposite to the nozzle means, the plug means having a passageway extending therethrough adapted for bringing a first gas into the chamber, the plug means having a passageway therearound adapted for bringing an additional gas into the chamber and introducing the additional gas into the chamber in an annular path between the plug means and the first electrode, means forming a passageway adapted for introducing other gas at a large number of peripherally spaced points between the first ring and fluid header means and the first electrode, gas inlet means forming a fourth passageway adapted for bringing further gas into the chamber and introducing the last-named gas between the first ring and a fluid header means and the second electrode at a large number of peripherally spaced points, gas introducing means forming a fifth passageway adapted for bringing still further gas into the chamber and introducing the last-named gas between the second electrode and the second ring and fluid header means at a large number of peripherally spaced points, and gas introducing means forming a sixth passageway adapted for bringing an ancillary gas into the chamber and introducing said last-named gas at a large number of peripherally spaced points in the area between the second ring and fluid header means and the nozzle means, at least two passageways spaced from each other being utilized to bring process and quenching gases into the chamber, said two passageways being selected in accordance with the composition of the process gas and the composition of the desired recombination product.

5. An arc heater for chemical processing comprising means forming an arc chamber, said means including a pair of axially spaced annular electrodes with a ring shaped heat shield therebetween, exhaust means for the arc chamber, the electrodes being adapted to be connected to terminals of opposite polarity respectively of a source of potential to produce and sustain an are therebetween, the arc extending substantially parallel to the longitudinal axis of the chamber, magnetic field coil means disposed in both electrodes and adapted to be energized to set up a magnetic field which causes the arc to rotate and form a substantially cylindrical axially extending arc path between electrodes, means for introducing a process gas at a plurality of peripherally spaced but substantially axially aligned points adjacent the upstream end of the cylindrical arc path, the arc having a predetermined power and the gas flow rate being such that the process gas is pyrolyzed by the are at a predetermined temperature, the desired recombination product being one which requires the process gas to be quenched in a time of the order of microseconds to a predetermined temperature, and means for introducing a cooling quenching gas at a plurality of peripherally spaced but substantially axially aligned points also adjacent the cylindrical arc path but downstream of the first named plurality of peripherally spaced points.

6. An arc heater for chemical processing comprising means forming an arc chamber, said means including a pair of axially spaced annular electrodes with a ring shaped heat shield therebetween, exhaust means for the arc chamber, the electrodes being adapted to be connected to terminals of opposite polarity respectively of a source of potential to produce and sustain an arc therebetween, the arc extending substantially parallel to the longitudinal axis of the chamber, magnetic field coil means disposed in both electrodes and adapted to be energized to set up a magnetic field which causes the arc to rotate and form a substantially cylindrical axially ex tending arc path between electrodes and adjacent said ring shaped heat shield, the ring shaped heat shield having a plurality of axially and peripherally spaced holes therein communicating with at least one annular fluid passageway within and extending substantially around the entire periphery of the ring shaped heat shield, one end of the arc path being the upstream end and the other end of the arc path being the downstream end, means for introducing a process gas into the arc chamber in a generally cylindrical path not farther downstream than the cylindrical arc path, the process gas being pyrolyzed by the arc, and means for introducing a quenching fluid into the arc chamber through said plurality of axially and peripherally spaced holes at positions adjacent the cylindrical arc path to quench the pyrolyzed gas to a predetermined temperature.

7. An arc heater for chemical processing comprising means forming an arc chamber, said means including a pair of fluid-cooled axially annular electrodes with a ring-shaped heat shield therebetween, the ring-shaped heat shield having an annular passageway therein for the flow of cooling fluid therein, exhaust means for the arc chamber, the electrodes being adapted to be connected to terminals of opposite polarity respectively of a source of potential to produce and sustain an arc therebetween, the are extending substantially parallel to the longitudinal axis of the chamber, magnetic field coil means so mounted with respect to the electrodes that a magnetic field is set up which causes the arc to rotate substantially continuously and form a substantially cylindrical arc path between electrodes, means for introducing a process gas at a plurality of spaced points axially within the cylindrical arc path and near the upstream end thereof, the are having a predetermined power and the gas flow rate being such that the process gas is pyrolyzed by the arc and a predetermined average pyrolyzed gas temperature produced, the desired recombination product being one which requires the process gas to be quenched in a predetermined time to a predetermined temperature, and means for introducing a cooling quenching gas at a plurality of peripherally spaced points also axially within the cylindrical arc path but near the downstream end thereof, the ring-shaped heat shield having a plurality of axially and peripherally spaced holes therein communicating from the arc chamber to the fluid flow passageway therein whereby an additional quenching material in the form of a fluid is introduced into the arc chamber over a substantial portion of the axial extent of the cylindrical arc path.

8. An arc heater for chemical processing comprising means forming an arc chamber, said means including a pair of axially spaced annular electrodes with a ringshaped heat shield therebetween, the electrodes being adapted to be connected to terminals of opposite polarity respectively of a source of potential to produce and sustain an arc therebetween, the are extending substantially parallel to the longitudinal axis of the chamber, magnetic field coil means so mounted with respect to both electrodes that a magnetic field is set up which causes the arc to rotate and form a substantially cylindrical arc path between electrodes, means for introducing a process gas into the chamber simultaneously at a large number of peripherally spaced points whereby substantially all of the process gas passes through the arc path, the dwell time of any portion of the process gas in the arc path being substantially uniform whereby the process gas is heated and pyrolyzed at a substantially uniform temperature throughout, and means for introducing a quenching fluid into the chamber at another large number of peripherally spaced points simultaneously axially selected in accordance with the rate of gas movement through the are heater whereby at least a large portion of the pyrolyzed gas is substantially uniformly cooled to a temperature at which a desired recombination product is present in substantial proportion.

9. Are heater apparatus for chemical processing according to claim 8 including in addition still further means for introducing an additional quenching fluid into the chamber simultaneously at another large number of peripherally spaced points all axially downstream of the first named means for introducing a quenching fluid, the additional quenching fluid inhibiting further chemical recombination and inhibiting the formation of undesired recombination products.

10. Arc heater apparatus for chemical processing according to claim 8 including in addition still further means for introducing an additional quenching fluid at high axial velocity upstream of the cylindrical arc path and from a position substantially at the axial center of the cylindrical arc path whereby the additional quenching fluid does not substantailly interfere with the pyrolysis of the process gas but is mixed with the pyrolyzed process gas only after pyrolysis to a uniform temperature is substantially completed.

References Cited UNITED STATES PATENTS 2,952,706 9/1960 Lipscomb 23277 X 3,149,222 9/1964 Giannini et al. 2l9-121 X JAMES H. TAYMAN, 111., Primary Examiner.

U.S. Cl. X.R.

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