Abstract:
A method and apparatus for processing a waste product and producing a synthesis gas is provided. The system includes a sealed, heated rotatable drum for preheating and preparing the waste material suitable for a plasma reactor, and processing the material in the reactor. The synthesis gas created by the reactor is used to preheat the waste material by circulating the hot synthesis gas around the drum. In an alternative embodiment, the hot synthesis gas flows through the drum to preheat the waste material and to clean the synthesis gas. Different methods of cooling and cleaning the synthesis gas are used. The system may comprise two plasma reactors in combination with a rotating desorber drum.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    None.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The present invention relates generally to the field of processing a waste product and producing synthesis gas (“syngas”) and useable solid products. More particularly, this invention relates to a method and apparatus for processing a waste product, secondary material, or other feedstock containing carbon by employing a heated rotatable drum and a plasma reactor.  
           [0005]    2. Background of the Invention  
           [0006]    A gasification system is generally defined as an enclosed thermal device and associated gas cleaning system or systems that does not meet the definition of an incinerator or industrial furnace, well known to those skilled in the art, and that: (1) limits oxygen concentrations in the enclosed thermal device to prevent the full oxidization of thermally disassociated gaseous compounds; (2) utilizes a gas cleanup system or systems designed to remove contaminants from the partially oxidized gas that do not contribute to its fuel value; (3) transforms inorganic feed materials into a molten, glass-like substance (“slag”) at temperatures above 2000° F.; and (4) produces a synthesis gas.  
           [0007]    Utilizing a plasma arc to gasify a material is a technology that has been used commercially for many years. Most plasma arc reactors produce a high quality syngas that can be used as a building block for other chemical manufacturing processes or as a fuel for energy production. Many feeds containing hydrocarbons, such as oil, coal, refinery residuals, and sewage sludge have all been successfully used in gasification operations. It is sometimes desirable to convert a hazardous stream of material into a useable product by gasifying the material. Upon gasification, the hazardous material, or feed, will typically be converted into a useable syngas and a useful molten material, or a molten glass-like substance called slag or vitreous frit. Since the slag is in a fused, vitrified state, it is usually found to be non-hazardous and may be disposed of in a landfill as a non-hazardous material, or sold as an ore, road-bed, or other construction material. It is becoming less desirable to dispose of waste material by incineration or desorption because of the extreme waste of fuel in the heating process and the further waste of disposing, as a residual waste, material that can be converted into a useful syngas and solid material.  
           [0008]    Generally, the gasification process consists of feeding carbon-containing materials into a heated chamber (the gasifier) along with a controlled and limited amount of oxygen and steam. At the high operating temperature created by conditions in the gasifier, chemical bonds are broken by thermal energy and by partial oxidation, and inorganic mineral matter is fused or vitrified to form a molten glass-like substance called slag or vitreous frit. With insufficient oxygen, oxidation is limited and the thermodynamics and chemical equilibrium of the system shift reactions and vapor species to a reduced, rather than an oxidized state. Consequently, the elements commonly found in fuels and other organic materials end up in the syngas.  
           [0009]    However, the carbon-containing feed materials may be difficult to manage because they are typically in an improper form for gasification. Furthermore, syngas produced by a plasma reactor is usually very hot, dirty, and difficult to manage. Therefore the industry would welcome a gasification system which is self-regulating, self-cleaning, and which produces a higher quality syngas and/or useable solid by-product.  
           [0010]    The present invention overcomes certain deficiencies of the prior art.  
         BRIEF SUMMARY OF THE PREFERRED EMBODIMENTS  
         [0011]    Disclosed is an apparatus and method for processing a waste stream wherein a heated, sealed rotatable drum preheats and prepares the waste stream for gasification within a plasma reactor. The synthesis gas (syngas) produced by the reactor is used to heat the rotatable drum and, consequently, cool the syngas. The syngas is a useable product and the molten metal, glass, and slag is useable or disposable as a non-hazardous material. The hot syngas may be blended with a colder gas and the blend used to preheat the feed. The hot syngas also may be conveyed through the inside of the rotating drum to cool and clean the gas, as well as to preheat the feed.  
           [0012]    Another embodiment described herein includes a first plasma reactor to gasify the solid material in the feed, and a second plasma reactor to treat the untreated vapors, with the heat from the first reactor, or the second reactor, used to heat the rotating drum.  
           [0013]    The disclosed devices and methods comprise a combination of features and advantages which enable them to overcome certain shortcomings of the prior art methods and apparatus. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    For a detailed description of preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:  
         [0015]    [0015]FIG. 1 shows a schematic view of a plasma reactor.;  
         [0016]    [0016]FIG. 2 shows a schematic view of an alternative plasma reactor;  
         [0017]    [0017]FIG. 3 shows a schematic view of a waste processing plant using a rotating drum in combination with a plasma reactor;  
         [0018]    [0018]FIG. 4 shows a schematic view of an alternative waste processing plant using a rotating drum in combination with a plasma reactor;  
         [0019]    [0019]FIG. 5 shows a schematic view of a waste processing plant using a rotating drum in series with two plasma reactors;  
         [0020]    [0020]FIG. 6 shows a schematic view of another version of a waste processing plant using a rotating drum in combination with a plasma reactor that gasifies only the solids and high boilers that process the waste; and  
         [0021]    [0021]FIG. 7 shows a schematic view of an alternative waste processing plant using a rotating drum in series with two plasma reactors. 
     
    
     NOTATION AND NOMENCLATURE  
       [0022]    Certain terms are used throughout the following description and claims to refer to particular system components. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Also, the terms “connects,” “connected,” and “interconnected” are intended to mean and refer to either an indirect or a direct connection between components or apparatus. Thus, for example, if a first apparatus “connects with” or is “connected to” to a second piece of equipment or apparatus, that connection may be through a direct connection of the two devices, such as by a conduit, or through an indirect connection via other devices, apparatus, conduits and other intermediate connections. As an even more specific example, a first apparatus may be connected to or interconnected with a second apparatus (by conduit or piping, for example) even where there is a third device or apparatus in between the two.  
         [0023]    Further, the present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention, including an apparatus and method for processing a waste product so that it is converted into useable gases, liquids, and solids. This exemplary disclosure is provided with the understanding that it is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. In particular, various embodiments of the present invention provide a number of different constructions and methods of operation. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.  
         [0024]    Reference to the term “waste” or “waste product” is intended to mean any feedstock which may contain carbon which will convert to syngas or other compounds which are desirable in the gas product or other elements which may contribute to the molten products. These feedstocks may be wastes, secondary materials, or raw materials for a manufacturing process. Further the term “syngas” means “synthesis gas” which is a gas manufactured by reforming compounds through conversion processes that involve thermal disassociation and partial oxidation. In the present invention, thermal disassociation and partial oxidation reactions occur between the waste feed and cooling mediums when subjected to a plasma arc. The resulting synthesis gas is commonly understood to be primarily composed of hydrogen and carbon monoxide, however, the composition of the gas produced in the presence of the plasma arc is not critical to the present invention. The gas may include any combination of elements or compounds present in the waste feed and/or cooling medium. To the extent that any term is not specially defined in this specification, the intent is that the term is to be given its plain and ordinary meaning as understood by a person of ordinary skill in the art.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    It is not intended to describe the complete operation of a plasma reactor, and the power supply used for powering and controlling the plasma torch of a plasma reactor, since a complete plasma reactor system, with power supply and controller, is known and can be purchased commercially. However, FIGS. 1 and 2 are simplified schematic drawings used to illustrate the basic operation of a typical plasma reactor.  
         [0026]    The plasma reactor of FIG. 1 is referred to as reactor  100 . Plasma torch  102  is provided with electrodes  104  that, when energized, produce arc  106 . Plasma torch reforming and cooling medium  114 , which is usually a controlled combination of air, steam, and/or oxygen, is injected to the inside of the torch via inlets  105  as shown by FIG. 1. When the reforming and cooling medium  114  contacts arc  106 , plasma  108  is produced that flows to the contacting chamber  110 , where the feed that is to be reformed  112  is injected and contacted by the plasma  108 . Plasma  108  is an ionized, conductive gas which is created by the interaction of a gas with the electric arc. Plasma  108  is at a controlled temperature, usually from 8,000° F. to 30,000° F.  
         [0027]    The molecules in the feed  112  that can be gasified are disassembled to their basic atoms and certain of the metals are melted. These atoms flow to collecting chamber  121  through opening  122  and reach a temperature, usually from 2000° F. to 3000° F., in collecting chamber  121 . The molten metals and glass  123  collect in the bottom of the collecting chamber and are drawn off through outlet  124 . The silicate slag  125  floats on top of molten metals  123  and is drawn off through outlet  126 , as shown in FIG. 1. At the lower temperature in collecting chamber  121 , the higher reactive atoms recombine and form the synthesis gas or syngas  120 . For example, one carbon atom combines with an oxygen atom and forms a carbon monoxide molecule (CO). The quantity of oxygen injected with feed  112  and reforming and cooling medium  114  is controlled since excessive oxygen combines with the carbon monoxide molecules and forms carbon dioxide (CO 2 ). Accordingly, the elements commonly found in the feed (C, H, O, S, CL) end up in the syngas  120  as CO, H 2 , H 2 O, CO 2 , N 2 , CH 4 , H 2 S, HCL with lesser amounts of COS, NH 3 , HCN, elemental carbon and trace quantities of other hydrocarbons.  
         [0028]    Syngas  120  in chamber  121  flows through outlet  128  of container  121  and to cyclone  130  through cyclone inlet  132 . Solids flow out bottom outlet  134  and cleaned syngas flows out top outlet  136 . The operation of a cyclone is well known by those familiar with the art.  
         [0029]    Referring now to FIG. 2, a simplified schematic drawing can be seen depicting the basic operation of another version of a plasma reactor. The plasma reactor of FIG. 2 is referred to as reactor  200 . The plasma torch of reactor  200  is provided with electrodes  204  that, when energized, produce arc  206 . Plasma torch reforming and cooling medium  214  flows to chamber  221  as shown by FIG. 2. When the reforming and cooling medium  214  contacts arc  206 , plasma is produced within chamber  221 . Some reactors having special graphite electrodes which may not require a cooling medium. As feed  212  enters chamber  221 , the molecules of feed  212  are disassembled to their basic atoms. The molten metals and glass  223  collect in the bottom of collecting chamber  221  and are drawn off through outlet  224 . The silicate slag, aluminates, and other salts  225  float on top of molten metals and glass  223 , and are drawn off through outlet  226 . The higher reactive atoms recombine and form the syngas  220  which flows through outlet  228  of chamber  221  to inlet  232  of cyclone  230 . Solids collected by the cyclone, mostly carbon, flow out bottom outlet  234  of cyclone  230  and syngas flows out the top outlet  236 .  
         [0030]    Referring next to FIG. 3, a process plant  300  incorporating a plasma reactor  301  is shown. The apparatus processes waste product and produces useful products including syngas, molten metals, and silicate slag that can be used for various types of construction or building material.  
         [0031]    As shown in FIG. 3, process plant  300  includes a plasma reactor  301 , such as the previously described reactors of FIGS. 1 and 2. Reactor  301  comprises a collecting chamber  321 , a contacting chamber  310 , and a plasma torch  302  with attached cooling and reforming medium supply  314  and electric supply  315 . Molten metal flows out the bottom outlet  324  of chamber  321 ; silicate slag flows out outlet  326 ; and syngas  320  flows out top outlet  328 . Syngas  320  then flows through inlet  332  of cyclone  330 . Subsequently, separated solids flow out outlet  334  of cyclone  330  and clean syngas flows out top outlet  336 . Syngas  320  then flows through inlet  342  of venturi exhauster  340 , which is known to those skilled in the art and is commercially available. Syngas  320  flows out outlet  344  to the inlet  355  of outside enclosure  362  of rotating drum  360 .  
         [0032]    Plant  300  also includes rotatable drum  360 . The operation of rotating drum  360 , as well as other features and details of drum  360 , is described in the following patents, which are hereby incorporated herein by reference: U.S. Pat. No. 5,078,836 entitled “Method and Apparatus for Retorting Material,” U.S. Pat. No. 5,227,026 entitled “Retort Heat Exchanger Apparatus,” and U.S. Pat. No. 5,523,060 entitled “Apparatus for Retorting Material.” Thus, rotating, mounting, and other means associated with drum  360  are not described herein because the components and operation of rotating drum  360  is sufficiently disclosed in the above-referenced patents.  
         [0033]    Drum  360  is attached to stationary inlet bulkhead  363  by seals  364  and attached to stationary outlet bulkhead  366  by seals  367 . Seals  364  and  367  separate the inside of the drum from the outside. The drum is configured such that feed  311  placed through the inlet bulkhead opening  365  progresses through the drum to the outlet opening  368 . Drum  360  is enclosed by stationary enclosure  362  and attached to drum  360  by seals  351 . Enclosure  362  is provided with hot syngas  320  via gas inlet  355  and gas outlet  357  so that hot syngas  320  flows from the inlet to the outlet as shown by curves  347 , thereby heating drum  360 .  
         [0034]    Material to be processed  311  flows into rotating drum  360  and is heated by the hot syngas  320  that flows between the outside of drum  360  and the inside of drum enclosure  362  as shown by flow arrows  347 . In flowing through the rotating heated drum, the waste  311  is ground to a fine powder and most of the liquids are vaporized, thereby transforming material  311  into a prepared plasma feed. Prepared plasma feed  311  flows out bulkhead outlet  368  to plasma contacting chamber  310  through chamber conduit and inlet  312 . Sorter  316 , an apparatus for sorting and removing particles that are too large to be processed by the reactor, may optionally be placed in conduit  312 . Particles that are too large may be removed through line  317  and or returned to inlet line  311  or otherwise processed.  
         [0035]    Syngas  320  flows from collecting chamber  321  out outlet  328  through cyclone  330 , venturi exhauster  340 , and drum enclosure  362  as previously described. Syngas  320  then flows through conduit  348  to inlet  352  of recirculation blower  350 . Syngas  320  flows from outlet  354  of blower  350  to driving fluid inlet  346  of exhauster  340 . Recirculation blower  350  is used to increase the flow of gas around drum  360 , thereby improving the heat transfer rate. Exhauster  340  is used to blend the hot syngas  320  coming from reactor  301  with the cooler syngas  320  coming from drum  360  so as to obtain a more manageable temperature such as, for example, between 800° F.-2000° F. Excess syngas  320  is drawn off selectively from outlet  354  by stream  337 , which is controlled by control valve  356 . Control valve  356 , well known by those familiar with the art, is usually controlled by the desired temperature of prepared feed  312  before feed  312  enters mixing chamber  310 .  
         [0036]    After being processed by rotating heated drum  360 , the prepared feed  312  consists of vapors and pulverized solids. It is necessary to pulverize the solids since the plasma reactor  301  is unable to process lumps or larger pieces of solids. The above referenced and incorporated patents teach how the rotating drum  360  is used to pulverize the solids.  
         [0037]    Referring now to FIG. 4, a schematic drawing illustrates another embodiment of the present invention combining a waste processing drum with a plasma reactor. The embodiment of FIG. 4 may be preferred because it is more economical than the embodiment of FIG. 3, depending mainly on the composition of the unprepared feed. For example, in treating a feed containing a high percentage of condensables, such as water or light hydrocarbons that do not need to be processed by the plasma reactor, the embodiment of FIG. 4 may be preferred over that of FIG. 3.  
         [0038]    The apparatus of FIG. 4 is referred to as process plant  400 . Plant  400  includes rotatable drum  460  which is attached to stationary inlet bulkhead  463  by seals  464  and attached to stationary outlet bulkhead  466  by seals  467 . Seals  464  and  467  separate the inside of drum  460  from the outside. Drum  460  is configured such that unprepared feed  411  placed through the inlet bulkhead opening  465  progresses through the drum to the outlet opening  469 .  
         [0039]    Plasma reactor  401  comprises a collecting chamber  421 , a contacting chamber  410 , and a plasma torch  402  with attached cooling and reforming medium supply  414  and electric supply  415 . Molten metal flows out the bottom outlet  424  of chamber  421 ; silicate slag flows out outlet  426 ; and syngas  420  flows out top outlet  428 . Syngas  420  flows through inlet  461  of bulkhead  466 . Syngas  420  then flows through the inside of drum  460  to the outlet opening  468  of bulkhead  463 . In flowing through drum  460 , the hot syngas  420  is cooled and the feed  411  is heated, vaporizing all of the water and light constituent portions of feed  411 . Drum  460  is also provided with outer shell  462  having seals  449 .  
         [0040]    Material to be processed  411  flows through the inside of rotating drum  460 , and is heated by the hot syngas  420  which also flows through drum  460  as shown by flow arrow  429 . After being processed by drum  460 , materials to be processed  411  exit drum  460  via outlet  469  of bulkhead  466  as prepared feed  412 . Syngas  420 , as well as other vapors vaporized from the feed  411 , exits drum  460  via outlet  468  of bulkhead  463 . This exit stream  452  flows to inlet  456  of venturi scrubber  454 . Hot streams, such as stream  452 , sometimes contain large hydrocarbon molecules which vaporize in the drum, but which also may condense and foul the conduit out of the drum. Therefore, an external rotatable auger with seal (not shown) may be installed somewhere along the stream  452  conduit which can drill and clean the conduit in a few seconds, without the need to shut down plant  400 .  
         [0041]    Syngas  420  flows from outlet  459  of venturi  454  to scrubber inlet  472  of scrubber  470 . Scrubber  470  contains demister element  478 , well known by those familiar with the art. Syngas  420  flows up the inside of scrubber  470 , as shown by arrow  474 , through demister  478 , and out outlet  479  to become product stream  436 . The liquid elements flow down the inside of scrubber  470 , as shown by arrow  476 , and out the bottom outlet  471  to the inlet  481  of pump  480 . After passing through pump  480 , the liquid elements flow out pump outlet  482 , then through air cooler  484  and out air cooler outlet  486 . The liquid stream is then divided into venturi driving stream  488  that goes to venturi driving inlet  458  and stream  491  that goes to liquid disposal stream  496 . The flow of stream  496  is controlled by control valve  492  which, in turn, is controlled by level controller  493 .  
         [0042]    The liquid in the bottom of scrubber  470  contains some hydrocarbons and solids. Side stream  490  may be drawn off and controlled by hand control valve  494 , and centrifuged by centrifuge  495 . The solids stream  497  and the hydrocarbon stream  499  flow out of centrifuge  495 , as shown, and the water stream  498  is returned to the scrubber.  
         [0043]    Recirculation blower  450 , burner  451 , and fuel and oxygen supply line  453  all assist in providing optional startup and/or additional heat to drum  460 . Burner  451  may optionally supply heat to the drum during startup and operation. When burner  451  is used, blower  450  recirculates hot gas from shell  462  via inlet  442  to burner  451  via outlet  444  as shown by arrow  440 . Exhaust gas flows to the atmosphere by exhaust stack  448 .  
         [0044]    Referring to FIG. 5, a schematic drawing shows a further embodiment of the present invention. The apparatus of FIG. 5 is referred to as process plant  500 . Plant  500  includes rotatable drum  560  that is attached to stationary inlet bulkhead  563  by seals  564  and attached to stationary outlet bulkhead  566  by seals  567 . Seals  564  and  567  separate the inside of drum  560  from the outside. The drum is configured by sloping the drum and/or having internal baffles (not shown) that lift and push the feed forward, as taught by the above-referenced and incorporated patents, such that feed  511  placed through the inlet bulkhead opening  565  progresses through the drum to the outlet opening  578 , yet hot gas flowing through nozzle  561  flows back through the drum to outlet  568 .  
         [0045]    Plant  500  also includes a plasma reactor  501 . Reactor  501  comprises collecting chamber  521 , contacting chamber  510 , and plasma torch  502  extending from contacting chamber  510  and including inlets for a cooling and reforming medium supply  514  and electric supply  515 . Molten metal flows out the bottom outlet of chamber  521  through outlet  524 ; silicate slag flows out outlet  526 ; and syngas  520  flows out top outlet  528 . Syngas  520  flows through inlet  561  of bulkhead  566 . Syngas  520  then flows through the inside of drum  560  to the outlet opening  568  of bulkhead  563 . While flowing through drum  560 , hot syngas  520  is cooled and the unprepared feed  511  is heated, vaporizing the water and light constituents.  
         [0046]    Feed  511  flows through the inside of rotating drum  560  and is heated by hot syngas  520  that flows through the drum as shown by flow arrow  529 , thereby forming prepared feed stream  512 . Syngas  520 , as well as other vapors vaporized from the feed, referred to as exit stream  552 , then flows out outlet  568  of bulkhead  563  and into cross exchanger  570 . Cross exchanger  570  preheats stream  552 , converting it to preheated stream  5122 , which then flows to contacting chamber  5102  of plasma reactor  5012 , the second plasma reactor included in plant  500 . Plasma reactor  5012  comprises collecting chamber  5212 , contacting chamber  5102 , and plasma torch  5022  extending from contacting chamber  5102  and having inlets for an electric power supply and a supply of reforming and cooling medium, not shown but similar to those of reactor  501 . Collecting chamber  5212  contains molten metal outlet  5242 , slag outlet  5262 , and syngas outlet  5282 . Syngas  5202  flows from the collecting chamber  5212  to inlet nozzle  532  of cyclone  530 . The solids collected by cyclone  530  flow out nozzle  534  and clean syngas flows out nozzle  536  and then through cross exchanger  570  to become a cooler syngas stream  538 .  
         [0047]    [0047]FIG. 6 is a schematic drawing of yet another embodiment of the present invention. The apparatus of FIG. 6 is referred to as process plant  600 . Plant  600  includes a plasma reactor  601 . Reactor  601  comprises a collecting chamber  621 , a contacting chamber  610 , and a plasma torch  602  extending from contacting chamber  610  and having inlets for a cooling and reforming medium supply  614  and electric supply  615 . Molten metal flows out the bottom outlet  624  of chamber  621 ; silicate slag flows out outlet  626 ; and syngas  620  flows out top outlet  628 . Syngas  620  flows through inlet  632  of cyclone  630 , with separated solids then flowing out outlet  634  of cyclone  630  and clean syngas flowing out top outlet  636 . Syngas  620  then flows through inlet  642  of venturi exhauster  640  and through outlet  644  to the inlet  655  of outside enclosure  662  of rotating drum  660 .  
         [0048]    Plant  600  also includes rotatable drum  660 . Drum  660  is attached to stationary inlet bulkhead  663  by seals  664  and attached to stationary outlet bulkhead  666  by seals  667 . Seals  664  and  667  separate the inside of drum  660  from the outside. Drum  660  is configured such that feed  611  placed through the inlet bulkhead opening  665  progresses through the drum to the solids outlet opening  678 , and the vapors and gases produced inside of the heated and rotating drum  660  flow out the vapor outlet  658  of inlet bulkhead  663 . Drum  660  is enclosed by stationary enclosure  662  and attached by seals  651 . Enclosure  662  is provided with hot gas inlet  655  and hot gas outlet  657  so that hot gas flows from the inlet to the outlet as shown by curves  647  and heats the drum.  
         [0049]    Feed  611  flows through the inside of rotating drum  660  and is heated by the hot syngas that flows on the outside of drum  660  and on the inside of drum enclosure  662  as shown by flow curves  647 . While flowing through the rotating heated drum  660 , the feed  611  is ground to a fine powder and most of the liquids are vaporized. The solids from this prepared plasma feed flow out outlet bulkhead nozzle  678  and the vapors flow out outlet  658  of inlet bulkhead  663 . The solids stream  612  flows to plasma contacting chamber  610 , where it reacts with the plasma and forms molten metals, silicate slag, and syngas  620  as previously described. Syngas  620  flows from collecting chamber  621  through outlet  628 , cyclone  630 , venturi exhauster  640 , and to drum enclosure  662  as previously described.  
         [0050]    Syngas  620  then flows through conduit  648  to inlet  652  of recirculation blower  650 . Syngas  620  flows from outlet  654  of blower  650  to driving fluid inlet  646  of exhauster  640 . Recirculation blower  650  is used to increase the flow of gas around drum  660  and thereby improve the heat transfer rate. Exhauster  640  is used to blend the hot syngas  636  coming from reactor  601  with the cooler syngas coming from drum  660  (via conduit  648  and blower  650 ) to obtain a more manageable temperature, such as, for example, less than 2000° F. Excess syngas is drawn off selectively from outlet stream  654  of blower  650  by stream  637 , which is controlled by control valve  656 . Control valve  656 , well known by those familiar with the art, is usually controlled by the desired temperature of prepared feed  612  before feed  612  enters mixing chamber  610 .  
         [0051]    The vapors and gases produced inside of drum  660  flow through outlet  658  of inlet bulkhead  663  to inlet  674  of venturi scrubber  670 . The vapors and gases then flow to container  693  through venturi scrubber outlet  676 , with liquids collecting in the bottom of container  693  and gases flowing out outlet  672  to inlet  679  of scrubber  675 . Gases in scrubber  675  flow through demister element  678  and out outlet  673 , and liquids collect in the bottom of scrubber  675  and are selectively drained through outlet  677 . Venturi driving fluid pump  680  pumps liquid from container  693  through pump inlet  671  and through outlet  682  to conduit  683 . From conduit  683 , the liquids pass through cooler  684  to venturi scrubber inlet  688 . A side stream  691  can be drawn from the pump outlet  682  and becomes stream  696  that is controlled by control valve  692 . Stream  696  can include hydrocarbons, dirt, and/or water, and can be removed for separation by any separation means known in the art, including but not limited to, gravity, centrifuge, or a water treating system. Clean makeup water is returned through inlet  698  of container  693 , and liquid surface  695  is maintained and controlled by control valve  699  and level controller  697 .  
         [0052]    [0052]FIG. 7 is a schematic drawing of a further embodiment of the present invention. The apparatus of FIG. 7 is referred to as process plant  700 . Plant  700  includes a first plasma reactor  701  having a collecting chamber  721 , a contacting chamber  710 , and a plasma torch  702  extending from contacting chamber  710  having inlets for a cooling and reforming medium supply  714  and electric supply  715 . Molten metal flows out the bottom outlet  724  of chamber  721 ; silicate slag flows out outlet  726 ; and syngas  720  flows out top outlet  728 . Syngas  720  flows into inlet  732  of cyclone  730 , with the separated solids flowing out outlet  734  of cyclone  730  and clean syngas flowing out top outlet  736 . Clean syngas  720  then flows through cross exchanger  770  to become cooler product syngas stream  7382 .  
         [0053]    Plant  700  also includes a second plasma reactor  7012  to process the vapors and gases formed in the drum  760 . Plasma reactor  7012  comprises a collecting chamber  7212 , a contacting chamber  7102 , and a plasma torch  7022  having an electric power supply and a supply of reforming and cooling medium (not shown). Gases to be reformed flow from outlet  758  of inlet bulkhead  763  through cross exchanger  770  and into inlet  7122  of contacting chamber  7102 . Collecting chamber  7212  includes molten metal outlet nozzle  7242 , slag outlet nozzle  7262 , and syngas outlet nozzle  7282 . Syngas  7202  flows from the collecting chamber  7212  through outlet  7282  to inlet nozzle  7322  of cyclone  7302 . The separated solids collected by cyclone  7302  flow out nozzle  7342  and clean syngas flows out nozzle  7362  to inlet  742  of venturi exhauster  740 . Plant  700  allows solids to be processed by the first plasma reactor  701  and the relatively clean gas feed to be processed by the second plasma reactor  7012 .  
         [0054]    Rotatable drum  760  of plant  700  is attached to stationary inlet bulkhead  763  by seals  764  and attached to stationary outlet bulkhead  766  by seals  767 . Seals  764  and  767  separate the inside of drum  760  from the outside. Drum  760  is configured such that feed  711  placed through the inlet bulkhead opening  765  progresses through drum  760  to the solids outlet opening  768 , and the vapors and gases produced inside of the heated and rotating drum  760  flow out the vapor outlet  758  of inlet bulkhead  763 . Drum  760  is enclosed by stationary enclosure  762  and attached by seals  751 . Enclosure  762  is provided with hot gas inlet  755  and hot gas outlet  757  so that hot gas flows from the inlet to the outlet as shown by curves  747  and heats drum  760 .  
         [0055]    Feed material  711  flows through the inside of rotating drum  760  and is heated by hot syngas  7202  that flows between the outside of drum  760  and the inside of drum enclosure  762 , as shown by flow curves  747 . While flowing through rotating heated drum  760 , waste  711  is ground to a fine powder and most of the liquids are vaporized, with the solids from this prepared plasma feed flowing out bulkhead outlet  768  and the vapors flowing out outlet  758  of inlet bulkhead  763 . The prepared solids stream  712  flows to plasma contacting chamber  710 . Syngas  720  flows from collecting chamber  721  through outlet  728  into cyclone  730 , and then via outlet  736  to cross exchanger  770  forming product stream  7382  as previously described.  
         [0056]    Syngas  7202  flowing around drum  760  according to curves  747  flows through outlet  757  and conduit  748  to inlet  752  of recirculation blower  750 . Syngas  7202  then flows from blower outlet  754  to driving inlet  746  of venturi exhauster  740  and out outlet  744  of exhauster  740 . Cooler syngas  7202  has now been blended with hot syngas  7202 , and is returned to inlet  755  of drum enclosure  762 . Recirculation blower  750  is used to increase the flow of gas around drum  760  thereby improving the heat transfer rate. Exhauster  740  is used to blend the hot syngas  7202  coming from reactor  7012  with the cooler syngas coming from drum  760  to obtain a more manageable temperature in the range of, for example, less than 2000° F. Excess blended syngas is drawn off selectively from outlet stream  744  of exhauster  740  by stream  737 , which is controlled by control valve  756 . Control valve  756 , well known by those familiar with the art, is usually controlled by the desired temperature of prepared feed stream  712  before feed  712  enters mixing chamber  710 .  
         [0057]    Although the present invention and its advantages have been described in relation to the specifically illustrated embodiments, it should be understood that various changes, substitutions and alterations can be made without departing from the spirit and scope of the invention as defined by the claims. The following are some examples of such substitutions:  
         [0058]    The hot syngas  7202  from reactor  7012  used to heat drum  760  of FIG. 7 may be substituted with syngas  720  from reactor  701 .  
         [0059]    A vessel with spray nozzles can be used to clean and/or cool the various gas streams, instead of a venturi scrubber. Also, there are many other known methods of cleaning and cooling gas streams.  
         [0060]    Gas rotary lock valves or screw conveyors in the transfer lines between the drum and the reactors are not shown in the drawings, since they may or may not be required for different feeds and different modes of operation. Gas rotary lock valves and screw conveyors are well known by those familiar with the art.  
         [0061]    Certain of the vessels in the plants described herein require internal refractory insulation and the use of particular materials to provide protection from the intense hot streams. Such methods of heat protection are well known by those familiar with the art and are not described herein.  
         [0062]    The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. While the preferred embodiments of the invention and their methods of use have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are exemplary only, and are not limiting. Many other variations and modifications of the invention and apparatus and methods disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims. In particular, unless order is explicitly recited, the recitation of steps in a claim is not intended to require that the steps be performed in any particular order, or that any step must be completed before the beginning of another step.