Abstract:
Production of non-self-combustible gaseous product, combustible with added air or other oxygen source, by electric-arc processing of water-slurried fragmented carbonaceous feedstock (e.g., anthracite ore, or graphite ore, or carbon-rich residue) within an appropriate high-temperature reactor defining a reaction zone, as by and between spaced-apart high-temperature-resistant electrodes; also methods of compacting and slurrying such feedstock, and passing an electric arc through the compacted fragmented wetted feedstock, thus forming—and subsequently collecting from overhead—desired gaseous product; also apparatus for performing the foregoing steps and obtaining the non-self-combustible gaseous product—whose combustion effluent with added air or equivalent source of gaseous oxygen is substantially free of harmful gases, and also of liquid and/or solid particulates.

Description:
[0001]     This is a continuation-in-part of Ser. No. 10/750,393 filed Dec. 31, 2003. 
     
    
     TECHNICAL FIELD  
       [0002]     This invention concerns conversion of fragmentary carbon-rich feedstock, by electrical arcing, into non-self-combustible gas whose air-combustion effluent is free of noxious gases and particulates.  
       BACKGROUND OF THE INVENTION  
       [0003]     Underwater arcing of carbon in rod or other continuous form, to generate gaseous fuel, is disclosed in U.S. patents, as by Eldridge: U.S. Pat. No. 603,058; by Dammann: U.S. Pat. Nos. 6,183,608; 5,417,817 [et al.]; and U.S. Pat. No. 5,159,900; by Lee (et al.): U.S. Pat. No. 6,217,713; and by Richardson: U.S. Pat. Nos. 6,299,738 6,299,656 [et al.]; U.S. Pat. Nos. 6,263,838; 6,153,058; 6,113,748; 5,826,548; 5,792,435; 5,692,459; and 5,435,274. Yet such fuel and its production are rare.  
       SUMMARY OF THE INVENTION  
       [0004]     This invention enables commercially successful production of such environmentally friendly non-self-combustible gaseous fuel by exposing an aqueous slurry of fragmentary carbon-rich feedstock (e.g., anthracite ores, graphite ores, or pre-used carbon residues) to high-temperature electrical-arcing (i.e., plasma) conditions, in a suitable reaction zone, preferably water-flooded, and retrieving the resulting gaseous product, which collects thereabove.  
         [0005]     The reactor contains one or more sets of electrodes supplied with adequately high-voltage electricity, whether continuously or intermittently. Individual electrodes conduct simultaneously or in preselected or otherwise timed or random order, as may be preferred.  
         [0006]     Fragmented carbon-rich feedstock, is forwarded by a suitable (e.g., helical) conveyor to such reaction zone, where—in aqueous slurry form—it is is further compacted and wetted, then is greatly heated by and between arcing electrodes, preferably composed of tungsten or of one or more alloys thereof noted for durability under plasma-like conditions. The desired gaseous fuel evolves therefrom and collects thereabove, whence it is removed (as by pumping), such as for storage or use on-site or shipment by pipeline, truck, etc.  
     
    
     SUMMARY OF THE DRAWINGS  
       [0007]      FIG. 1A  is a block diagram of electrical equipment to implement this invention upon fragmented wetted carbon-rich feedstock; and  
         [0008]      FIG. 1B  is a block diagram of equivalent process steps thereof.  
         [0009]      FIG. 2A  is a side elevation, partly sectioned away, of means for conveying fragmented feedstock to a reaction zone in a high-temperature (electrical arcing) reactor of this invention; and  
         [0010]      FIG. 2B  is a transverse cross-section of such a reaction zone;  
         [0011]      FIG. 3A  is a front elevation of a multiple-electrode array, such as was shown transversely in  FIG. 2B ; and  
         [0012]      FIG. 3B  is a medial longitudinal section of an electrode useful in such a multiple electrode array—and/or similarly useful alone. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0013]      FIG. 1A  states (reading downward from the top) that electricity for practicing this invention is readily obtainable, as from an offsite High-Voltage A.C. Source  10  (e.g., a commercial supplier); and that such electricity therefrom or from a similarly suitable source is readily convertible, as by conventional Rectifier to D.C.  12 ; and that the output therefrom (future input to the subject feedstock) is readily provided, as in intermittent configuration, by Pulser and Shaper  14 , on the way to reaching Electrode Array(s)  15 .  
         [0014]     Pulse Timer  16  and Pulse Allotter  18  enable individual pulses of whatever predetermined size and shape to actuate (i.e., electrify or “fire”) Conducting Electrodes  20 , whether at random or according to preselected patterns—whichever may be preferred—in a designated Reaction Zone  65 .  
         [0015]      FIG. 1B  traces (also reading downward) the path of Fragmented Carbon-Rich Feedstock  30  as a related sequence of events: Add Water  31 , and—perhaps—Add Optional Ion Source  32  (e.g., acetic acid), resulting in Feedstock Aqueous Slurry  40 ; then Compress Slurry While Advancing  45  (to the reaction zone), and/or Compress Slurry While Stationary  55  (in that reaction zone).  
         [0016]      FIG. 1B  steps performed on the resulting Compressed Slurry of Feedstock  60  include Ground Slurry Electrically at One Side  70 , and then Apply Electrical Potential at Other Side  75 . These steps result in Electric Arcing (plasma) of Wet Feedstock  80 .  
         [0017]     Formation of the desired gaseous fuel product then ensues, thus enabling as further steps: Collect Gaseous Product Overhead  90 , and Discard or Recycle Feedstock Residue  99 , as may be pre-timed and/or may result from current human and/or instrumental monitoring.  
         [0018]      FIG. 2A  shows, in side elevation, hopper  1  adapted to receive fragmented feedstock  30  and guide it into the input end of conveyor housing  3 —partly sectioned away to reveal forwarding means (auger, helical rotor, or screw)  5  inside. Drive motor  6 , at left end of rotor shaft  2 , imparts axial rotation to forward the contents.  
         [0019]     The fragmented feedstock may enter the hopper wet but usually fairly dry and will be converted to an aqueous slurry  7 , as water (piped from an external source not shown) enters the conveyor via any of several adjustable inlets—such as  8   a  and  8   b —spaced along the housing top. One or more similarly adjustable outlets—such as  9 —is/are located at intervals along the conveyor underside to preclude excessive slurry fluidity. Rotation of the conveyer screw transports the feedstock slurry to, and discharges it into, such a reaction zone, an example of which is shown next.  
         [0020]     For simplicity the conveyor axis is shown as horizontal, but it might slant downward instead, so as to facilitate slurry travel to—and its discharge within—the reaction zone (seen in the next view).  
         [0021]      FIG. 2B  shows, mainly in transverse section, reaction zone  65  defined between left sidewall  24  and right sidewall  26  flanking—at their bases—floor  35 , and rising to ceiling (or other overhead cover)  85 , which here contains centrally located outlet valve  86  to enable venting and collection  90  of eventual gaseous product  100 .  
         [0022]     The reactor walls (shaded here for brick) preferably comprise brick, ceramic, stone, or other high-temperature-resistant material. Furthermore, here they prefeerably contain a network of refrigerant channels  39  connected to an external supply (not shown) to assure the structural integrity of the walls at the exceedingly high temperatures reached during electrical arcing in the reaction zone.  
         [0023]     The walls also hold water supply piping, with lateral outlet(s)  29  into reaction zone  65 , above sloping wall portions overhanging a pair of alcoves for the respective juxtaposable arcing means when at rest. Such withdrawal of array plates facilitates residue removal and also servesq to protect the electrodes from inadvertent damage.  
         [0024]     The arcing means comprise upstanding multiple-electrode array plate  61  on hollow horizontal shaft  63  (at the left) and a similar array of electrically conductive nubs  72  on grounding plate  71  on similar shaft  73  (at the right), both at least the former shaft being movable horizontally to and fro by respective external means not shown here. Such mounting enables counterposing of those respective arrays, compressing whatever feedstock is supported therebetween on floor  25 , and facilitating the desired electrical arcing. Extending leftward from hollow shaft  63  is electrical conductor cable  62 , which connects (not shown here) to a previously mentioned external high-voltage source. Such cable and the internal structure of such an electrode appear in  FIG. 3B . Both the electrode tips and the matching juxtaposable grounding nubs are arranged in the form of an extended or expanded version of a familiar domino pattern, as is illustrated and described in the next view.  
         [0025]      FIG. 3A  shows exemplary multiple-electrode array  15  housing face-on, exhibiting a pattern of thirteen electrodes A . . . to . . . M)—as though the familiar five-spotted domino were extended by adding an outer ring of three spots per edge (each corner being in two rows). Each such electrode is wired individually, to conduct electricity whenever—and so long as—is desired, as mentioned hereinabove.  
         [0026]      FIG. 3B  shows in longitudinal section, on a much larger scale, a single electrode of the multiple array of  FIG. 3A , sectioned lengthwise except at its conical tip  20 . Its tubular housing  52  surrounds insulated hot-wire  51 , whose bare end  56  seats in indentation  57  in base  59  of conducting conical electrode proper  20 , which screws (or snaps) into its surrounding housing end—as suggested by an unshaded tip portion of its housing (at lower right). Outer wall  52  of base tubing  52  has lateral outlets or “weep holes”  53  enabling water outflow therethrough (from an outside source—not shown) into adjacent slurry  60  when in use—as during electrical arcing.  
         [0027]     Both shafts are horizontally piston-actuated by conventional means (not shown) for varying interplate spacing, and compression of slurried between-plate feedstock thus facilitating and/or stimulating desired electric arcing in the feedstock therebetween. Related external components—e.g., high-pressure tubing, and fluid cooling, pumping, and storage means—are omitted here as well-known.  
         [0028]     Circulation of water into and through the individual electrodes via the hollow supporting shaft for the electrode array plate aids in cooling and stabilizing the electrode tips and also assists in maintaining fluidity of the neighboring feedstock slurry.  
         [0029]     During such ensuing electric arcing, the desired fuel gas forms and collects above the water that has flooded the feedstock itself. The fuel can be drawn off readily, as through overhead valved outlet  86 , by aid of conventional (preferably oil-free) pumping apparatus.  
         [0030]     After cessation of arcing, the respective array plates usually are retracted to their rest positions, in their respective alcoves, and unreacted residue  98  is removed from the reaction zone. Of course, such residue may undergo subsequent re-treatment in the same or another reactor—or may simply undergo some form of disposal  99 .  
         [0031]     Such removal is readily accomplished, as by sweeping residue back into the forwarding conveyor and reversing the rotation direction of its helical screw, thus converting it into an exit conveyor. Such disposal thereof may be accomplished by humans who enter the reaction zone via a door (not shown) in a side or end wall and/or by equivalent mechanical pushing or sweeping means.  
         [0032]     Refragmenting and/or re-slurrying whatever feedstock residue is left after cessation of arcing may facilitate its removal, whether by personnel or machinery, and whether for re-treatment or disposal.  
         [0033]     In the foregoing and/or equivalent arrangement(s), the resultant electrical arcing through the compressed flooded fragmented feedstock yields the desired non-self-combustible gaseous product, itself readily recoverable thereabove, as already noted, whether for immediate or future use, on-site or elsewhere. The gas itself, duly protected from contact with air or equivalent oxygen source, is quite stable and is readily and safely distributable to other user sites, as by pipeline, train, truck, or equivalent transport.  
         [0034]     Notwithstanding this description of exemplary embodiments of the present invention, useful modifications may be made in its structuring and/or operation—such as by adding, combining, deleting, or subdividing apparatus, compositions, parts, or steps—while retaining all or most of the advantages and benefits of this invention, which itself is defined most succintly in the appended claims.