Patent Document

This is a continuation in part application of U.S. patent application Ser. No. 09/272,674 filed Mar. 19, 1999, U.S. Pat. No. 6,105,275 that claims priority to U.S. Provisional Patent Application Ser. No. 60/078,554 filed Mar. 19, 1998. 
    
    
     SPECIFICATION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus for use in eliminating or significantly reducing emissions to the atmosphere from retort off-vapor by loading contaminated material into a rotary vacuum retort and continuously unloading one or more volatile contaminants and decontaminated material out of the rotary vacuum retort at high temperature and vacuum while minimizing the introduction of low boiling point gases. 
     2. Background of the Invention 
     Various thermal treatment systems have been, and continue to be, used to separate volatile from non-volatile substances. For example, thermal desorption units are commonly used to remove substances such as mercury and volatile organics from solids. The use of vacuum retorts for this purpose is known. 
     The use of a vacuum decreases the boiling point of volatile substances and decreases the number of molecular collisions per unit of space in time. By minimizing these molecular collisions, chemical reactions and decompositions can be decreased so that vaporization and separation process can be efficiently and productively utilized. 
     For example, U.S. Pat. No. 5,569,154 (Navetta) discloses an indirectly heated continuous non-rotating vacuum retort with an internal rotating screw feeder. Navetta teaches to load the system at ambient temperature through a rotary airlock or triple dump valve to maintain negative system pressure. An internal hollow screw feeder is used to mix and transport the material being treated through the vessel. Hot gases are passed through the hollow screw feeder to indirectly heat the material being treated within the retort. The hot processed solids exit the opposite end of the screw feeder through a second rotary airlock or triple dump valve to again maintain the negative system pressure. The evolved retort gases diffuse and/or are swept with purge gases into the off-gas treatment system where they are condensed. 
     Additionally, U.S. Pat. No. 5,433,562 (Swanstrom) discloses an indirectly heated batch non-rotating vacuum retort with an internal screw mixer. Swanstrom teaches to load the retort at ambient pressure and temperature, seal the vessel and internally mix the stationary vessel contents with a screw mixer while indirectly heating the vessel and applying medium to high vacuum. Once the process is complete, the heat is turned off, the vacuum released, and the material removed with a screw feeder at ambient pressure. The evolved retort off-gases diffuse and/or are swept with purge gases into the off-gas treatment system for removal from the gas phase. 
     These non-rotating systems employ stationary vessels with internal moving flights or screws. Difficulty in uniformly heating the flights and stationary vessel often occurs, leading to metallurgical failures and reduced equipment life. Often, these systems are operated at a lower temperature than the rotary vessel systems to minimize thermal stresses. The rotating retort evenly distributes the indirect heat allowing the use of higher temperatures with less thermal stress. In addition, the mixing dynamics are different between the non-rotating retort and rotating retort systems. Moreover, particle size reduction is extremely important, especially in ambient and low vacuum systems. In a high vacuum environment, the large pressure gradient between the interior of the particle and the vacuum space drives the volatilization of substances within the particles thereby reducing the need for extensive particle size reduction. The reasons these systems do not employ a rotating retort to overcome these problems is because of the difficulty in maintaining a high vacuum on a hot rotating vessel. The seals on a non-rotating system are simple and straightforward gaskets. 
     Several prior art systems disclose either heated rotating vessels under slight vacuums of less than 1 inch of mercury or heated non-rotating vessels operated at high vacuums of over 28 inches of mercury. The slight vacuum employed in these rotating systems is to prevent leakage of environmentally-regulated substances out of the retort and off-gas treatment system, while the high vacuum in non-rotating systems serves to shorten process times. Although the technology is well known, there are several drawbacks and limitations. 
     First, in the prior art low vacuum rotating systems, complex off-gas treatment equipment is required to remove contaminated particulates and regulated chemicals prior to discharge of the treated gases to the atmosphere. This complex off-gas treatment equipment is very large and expensive compared to the system&#39;s processing rate. Due to ever more stringent air emission regulations and the need to protect human health and the environment, these off-gas treatment systems continue to become even more sophisticated and costly. One of the primary reasons that the off-gas processing systems associated with these prior art thermal units are so complex and expensive is because of the high volume of contaminated particulates and combustion, sweep, and/or leakage gases exhausted from the retort during operation. 
     To reduce the size and complexity of the off-gas treatment systems, indirectly fired retort vessels are often used. Heat is applied to the outside of the retort or applied with resistance heaters. These systems reduce the amount of particulates and eliminate the combustion gases exiting the retort. The prior art systems, however, do not entirely eliminate the carry out of particulates from the retort and still require a relatively large amount of sweep gas to move the vaporizing chemicals out of the retort. Therefore, even though an improvement, prior art indirectly fired retorts still require relatively large and expensive off-gas treatment systems. 
     Additionally, there are many cases in that one or more of the components of the matrix and/or the substances to be separated are thermally sensitive. That is, one or more of the substances break down to unwanted substances and/or the stricture of one or more of the matrix components are altered that adversely affects subsequent treatment or reuse. Prior art systems employing heat and vacuum can be used for these situations. The use of vacuum lowers the boiling point of substances and, depending upon the substances involved, may allow the separation of volatile from non-volatile substances at below critical temperatures. 
     Additionally, the smaller the particle size, the greater the particle surface area, the faster the processing time, and the better the ultimate removal of the volatile species. The rotating retort is better in reducing particle size during processing and minimizing the production of clinkers compared to non-rotating systems employing internal mixing devices. Steel balls, chains, and similar devices can be added to the rotating retort to further improve particle size reduction capabilities during processing. 
     Moreover, U.S. Pat. No. 5,628,969 (Aulbaugh) discloses an indirectly heated batch rotary vacuum retort. Aulbaugh teaches to load the retort at rest at ambient pressure and temperature, seal the vessel and rotate the vessel to mix the contents while indirectly heating the vessel and applying medium to high vacuum. Once the process is complete, the heat is turned off, the vacuum released, and the material removed with a screw feeder at ambient pressure. The evolved retort off-gases diffuse into the off-gas treatment system for removal from the gas phase. 
     In addition, U.S. Pat. No. 5,517,004 (Blonk) discloses an inductively heated continuous rotary vacuum retort operating at below 3 millibar pressure. Blonk teaches to load the retort continuously from one of two vacuum chambers with dry bulk solids. When one chamber is empty, that chamber&#39;s discharge valve is closed and the full chamber&#39;s valve is opened. The retort vessel rotates to move the solids to the discharge point while heating the solids and applying a vacuum of zero pressure absolute to 3 millibar. The processed solids are continuously discharged at processing temperature into one of two evacuated chambers. When one chamber is full, that chamber&#39;s valve is closed and the empty chamber&#39;s valve is opened. The evolved retort off-gases are swept into the off-gas treatment system with carrier gases for removal from the gas phase. Blonk teaches a complicated and expensive method for loading dry bulk solids into a vacuum rotary retort and unloading hot processed solids from a rotary vacuum retort while processing at temperature under a very high vacuum. This system requires four stationary vacuum vessels, two for the load end and two for the unload end of the process, does not handle wet materials, must operate at extremely low pressures, and uses swept or purge gases to transport the volatile contaminants out of the retort. 
     The vacuum systems of the prior art allow or purposefully introduce air and very low boiling point inert purge gases, such as nitrogen, into their systems. Purge gases are often introduced to flush vapors out of the retort and into an off-gas treatment system. These gases, after commingling with the pollutant vapors, are introduced into treatment systems that attempt to separate the pollutant vapors from the gases. Air enters these systems when the vessels are loaded and unloaded and/or enters through the metallic rotary airlock and triple dump valves during processing. All off-gas treatment systems are designed to remove pollutants from a gas stream that will eventually be exhausted to the atmosphere. As the amount of the pollutant in the gas stream decreases, it is increasingly difficult and expensive to continue to remove it. 
     The vacuum in these prior art systems must be maintained by use of one or more vacuum pumps with a rated cfm capacity higher than the influx rate of the gases. After establishing a vacuum in these prior art systems, if the vacuum pump is turned off, the influx of gases and the production of vapors would soon allow the system pressure to return to ambient conditions. The presence of significant volumes of gases that ultimately pass through the off-gas treatment system acts in many ways to transport pollutants through the off-gas treatment system and dramatically increase the size and complexity of the system designed to reach ever more stringent air pollution control limits. Additionally, these gases impart a large amount of momentum to pollutant vapors and continuously push them through the treatment system as the gases rush in and through treatment system to the exhaust stack. 
     The consequences of the presence of significant amounts of these gases in the system are staggering. The prior art teaches mass collection for shipment to alternate location for disposal. Off-gas treatment equipment is extremely large, complicated, and costly and pollutants are still continuing to be spewed into the air at rates detrimental to human health and the environment. In addition, the prior art does not attempt to separate the volatile substances collected into different fractions to be collected and recycled. A thermal processing system is needed to overcome the vast limitations of prior art thermal systems by dramatically reducing system costs and complexity and decreasing pollutant emissions to the lowest level practically achievable. 
     Therefore, a simplified, far more versatile, and economical indirectly heated continuous rotary vacuum retort that minimizes off-gas treatment equipment and produces near zero retort off-vapor emissions is needed to process solids of widely varying particle size, liquid content and shape at higher temperatures and under wider vacuum conditions than currently exists. 
     Additionally, there exists a need to recover and reuse the resources comprising these off-vapor emissions by collection and separation of the off-vapor emissions into useful and productive components so that the economic value of these otherwise wasted resources can be realized while offering a reduction in emissions to the lowest level practically achievable. 
     SUMMARY OF THE INVENTION 
     The present invention is drawn to an apparatus and a method of using the apparatus. In the invention, solid and/or slurried materials to be treated of varying size and liquid content are loaded from an area of ambient pressure into a heated, rotating retort operating under negative pressure or a vacuum. In the preferred embodiment, a combination piston and pinch valve arrangement is used and allows the feeding of wet, sticky, or dry solids that contain objects capable of periodically clogging and causing air leakage in other airlock systems. When closed, the pinch valves can completely seal around solids and the piston shaft to insure the integrity of the system vacuum. The pinch valves are preferably elastomers to avoid the creation of gaps, thereby causing an influx of air and a loss of system vacuum. 
     By feeding solids or slurried materials to be treated of varying size and liquid content in this manner, the present invention overcomes the difficulties of the prior art and provides a simplified, continuous method of removing and separating volatile substances from non-volatile substances, such as soil. 
     The preferred embodiment employed herein utilizes elastomeric pinch valve airlocks to isolate the system from the atmosphere and conveying material through the airlocks. Moreover, by using elastomeric seals between the rotating and non-rotating components at the rotating to/from non-rotating junctions, the vacuum loss associated with these interfaces is significantly reduced or eliminated. Furthermore, the inclusion of at least one material transfer device aids in the movement of material. Finally, through the use of a dryer prior to and a heat exchanger after the rotary retort process, heat can be recaptured and reused, the contaminated material or material to be treated can be dried, and the decontaminated material or treated material cooled and efficiently passed through a low temperature airlock arrangement to discharge. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustrating a preferred embodiment of the invention. 
     FIG. 2 is a cut away close-up of a preferred embodiment of the vapor transfer pipes. 
     FIG. 3 is a flow chart of a preferred embodiment of the off-vapor treatment system. 
     FIG. 4 is a side view of an alternative embodiment of an airlock to be used in the present invention. 
     FIG. 5 is a side view of an alternative embodiment of an airlock to be used in the present invention. 
     FIG. 6 is a side view of an alternative embodiment of an airlock to be used in the present invention. 
     FIG. 7 is a side view of an alternative embodiment of an airlock to be used in the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Gases including, but not limited to, oxygen, nitrogen, and carbon dioxide affect the collection of vapors and similar substances. As used herein, “vapors and similar substances” refer to substances near their condensation temperature at ambient conditions of temperature and pressure. The following preferred apparatus and method of its use separates these vapors and similar substances, also referred to as volatile contaminants, from the material being treated, also referred to as contaminated material, to create decontaminated or treated material wherein the volatile contaminants have been minimized. By initially removing gases, especially very low boiling point gases, prior to treatment in the retort described herein, the apparatus and method of its use efficiently capture virtually all of the vapors and volatile contaminants generated in the retort and dryer. As the contaminated material proceeds through the apparatus and is heated, some volatile contaminants vaporize. The apparatus will draw and collect these vapors from the material being treated for off-vapor treatment. 
     As set forth in FIG. 1, material to be treated is loaded into storage container  1 . Piston  6  movably attached to storage container  1  pushes the material to be treated toward airlock  4  preferably comprising a plurality of pinch valves  2  and  3 . As depicted in FIG. 1, piston  6  pushes the material to be treated toward pinch valve  2 . As the material to be treated approaches pinch valve  2 , pinch valve  2  opens to allow the material to be treated and piston  6  to enter airlock compartment  4  area. Once the material to be treated and piston  6  have entered airlock compartment  4 , pinch valve  2  is closed. At this point, airlock compartment  4  is evacuated by vacuum port  5 . Any device capable of generating a vacuum may evacuate the gases such that the vacuum may preferably approach zero pressure absolute. 
     A vacuum is pulled in airlock compartment  4  with the ambient temperature gas being exhausted to the atmosphere, passing into its own treatment system, or passing into a dryer and/or retort off-gas treatment system. Ideally, storage container  1  can be filled such that piston  6  will push and nearly fill airlock compartment  4  with material to be treated, thus eliminating or at least significantly reducing the amount of ambient temperature vapors or gasses to be removed. 
     Moreover, pinch valves  2  and  3  located at the beginning of this process and a plurality of pinch valves  35  and  36  that will be discussed in more detail herein are most preferably elastomeric pinch valves. Rubber, Viton®, or similar components are especially acceptable to provide the efficient protection of the reduced pressure environment demonstrated herein. Moreover, though metal valves may prove to be less efficient in this configuration, their use should be evident to those skilled in the art. The usage of non-elastomeric pinch valves merely requires additional maintenance of the vacuum and the associated treatment of gases contained therein. 
     Returning to the process, once the material to be treated has been collected within airlock compartment  4 , pinch valve  2  has been sealed, and the pressure has been reduced through vacuum port  5 , if necessary, pinch valve  3  is opened and piston  6  pushes the material to be treated such that it may move down airlock  4  to dryer pathway  15  and enter dryer  7 . 
     A dryer screw feeder  13  comprising a spiral thread is used in the most preferred embodiment to convey the material being treated through dryer  7 . As dryer screw feeder  13  rotates, the material being treated moves through dryer  7 . As material being treated moves, hot gases passing from dryer gas pathway  11  spiral about dryer spiral gas pathway  9  formed by the dryer fin spiral arrangement  8  arranged about the exterior of dryer  7  and within insulated firebox  17 . The dryer spiral arrangement  8  comprises a continuous barrier that approaches the firebox  17  such that gases are encouraged to travel about dryer  7  in a spiraled fashion. This arrangement effectively lengthens the path about dryer  7  and allows more of the heat within the gases to transfer to dryer  7 . Hot gases from retort dryer gas pathway  11  spirally traverse dryer spiral gas pathway  9  and exit through exhaust port  10 . As the material being treated moves through dryer  7 , heat is transferred from the hot gases passing about the exterior of dryer  7  into the material being treated. Moreover, the spiraling hot gases create a temperature gradient along dryer  7  and rotary retort  20 . This temperature gradient allows the selective separation and collection of substances with progressively higher boiling points along the length of rotary retort  20  as described below and shown in a preferred embodiment and method of use in FIG.  2 . 
     As the material being treated moves through the full extent of dryer  7 , dryer screw feeder  13  displaces the material being treated such that it falls through dryer retort pathway  16 . In the preferred embodiment, vapor discharge pipe  14  allows water vapor and low boiling point substances to be removed from the system and treated, if desired. 
     A retort screw feeder  24  axially rotates and effectively displaces the material being treated in a similar fashion as dryer screw feeder  13 . As the material being treated enters rotary retort  20  it is ushered forward to rotary retort spiral flighting  22  formed about the interior of rotary retort  20 . Hot off-gases are directed about rotary retort  20  along rotary retort spiral gas pathway  19  that is defined by a series of rotary retort fins  21  formed in the exterior of rotary retort  20  and firebox  17 . In a similar fashion as with dryer  7 , rotary retort  20  is heated by these gases. This configuration uses the same gases to heat both rotary retort  20  and dryer  7 . 
     Additionally, the creation of a temperature gradient along the axis of dryer  7  and/or rotary retort  20  not only maximizes the contact of the hot combustion gases passing through pathways  9 ,  11 ,  19 , and  25 , but allows the selective volatilization of substances with different boiling points. Though many methods of providing the preferable temperature gradient will be evident to those skilled in the art, including, but not limited to wrapping the vessels in electrical resistance tape, heating the vessels by electrical induction, and subjecting the vessels to heated or super heated steam, the preferred embodiment utilizes burner  12  to heat the gases that are spirally propelled about dryer  7  and rotary retort  20  within firebox  17 . 
     As the material being treated moves through rotary retort  20  and interacts with spiral flighting  22 , vapors separate from the material being treated. Transfer pipe  23  extends within the rotary retort and provides a preferred location for maintaining the vacuum or reduced pressure on the overall system by using vacuum generator  28  shown in FIG. 3 or similar pressure reducing device. Additionally, transfer pipe  23  provides a conduit for drawing the vapors from the material being treated during the separation process. In the preferred embodiment and method of use, vacuum generator  28  maintains between 2.25 mm Hg and 735 mm Hg pressure. A condensable vapor can be bled into retort  7  at port  27 . By issuing a small, constant amount of condensable vapor, preferably steam, at this point, the substances volatizing from the material being treated will be ushered along into transfer pipe  23 . This bleeding of condensable vapor effectively creates a condensable vapor shield that minimizes substances volatizing from the material being treated from traveling down retort to heat exchanger pathway  29  and reassociating with the treated material as it is cooled in heat exchanger  30 . 
     Referring to FIG. 2, a bundle of transfer pipes  23   a ,  23   b ,  23   c , and  23   d  with variable entrances  26   a ,  26   b ,  26   c , and  26   d , respectively, can be longitudinally positioned within rotary retort  20  such that the temperature gradient caused by the heat transferred from the hot gases spiraling about the exterior of rotary retort  20  allow substances with different boiling points to vaporize at different points along the length of rotary retort  20 . As shown, a substance with a relatively low boiling point will vaporize earlier from the material being treated as it traverses rotary retort  20 . This vapor would be drawn into the entrance  26   a  of transfer pipe  23   a  while a substance with a higher boiling point would vaporize farther along rotary retort  20  and be drawn into entrance  26   d  of transfer pipe  23   d , for example. This selective capture of vapors with increasing boiling points insures that low boiling point substances are not exposed to higher temperatures that could provide sufficient thermal energy to break chemical bonds. 
     Referring to FIG. 3, transfer pipe  23  may lead to an off-vapor treatment system that may comprise a plurality of impingers, condensers, and similar devices known to those skilled in the art. In the most preferred embodiment, it is envisioned that one or more condensers operating at different temperatures can be helpful in selectively separating vapors and gases collected. Additionally, the use of impinger solutions with different chemistries, such as aqueous solutions of different pH levels and organic solutions with different polarities, may also be helpful. Moreover, the present invention may be used in conjunction with adsorbents and molecular sieves to provide further separation and classification. 
     Additionally, the vacuum generator  28 , capable of maintaining the vacuum on the system, is in communication with transfer pipe  23 , normally via at least one separator as depicted in FIG.  3 . The use of a vapor compression device in conjunction with the vacuum generator  28  is envisioned to allow the pressurization of the vapors being collected from the system. Moreover, the use of cryogenic cooling at this point allows the condensation of substances that remain after the interaction with the impingers, condensers, and similar devices and may be passed onto a vapor compression unit. Effectively, pollutant emissions are reduced to near zero by virtually eliminating the amount of oxygen, nitrogen, carbon dioxide, and similar gases from the system, and condensing all vapors in the off-vapor treatment system. Similarly, the vacuum or pressure reduction occurring in airlocks  5  and  37  may collect trace vapors or gases that may be treated similarly. In the preferred method of use, however, these gases arc treated separately from the vapors drawn from the material being treated in the dryer  7  and rotary retort  20 . 
     As shown in a preferred embodiment of the off-vapor treatment system in FIG. 3, at least one separator  41 ,  42 ,  43 , or  44  is in communication with transfer pipe  23  and vacuum generator  28 . Those skilled in the art will recognize that any plurality of separator can effectuate this system. As shown, a plurality of separators  41 ,  42 ,  43 , and  44  are arranged to effect separations of the vapors into different groups based upon properties including, but not limited to, solubility in organic and aqueous solutions of different pH levels and polarity, boiling points, condensation points, and ionic strength. Other chemical and physical property differences that could be used as a basis for separation are evident to those skilled in the art. Preferably, the arrangement of separators  41 ,  42 ,  43 , and  44  economically separates various volatile substances that have been drawn from the material being treated. In practice, the fractional distillation treatment method used by petrochemical plants to produce various boiling point range condensates from crude oil is but one representative example of the separation technology that may be drawn upon in adapting, reconfiguring, or otherwise substituting components in this system. 
     In the arrangement depicted in FIG. 3, numerous pipes or similar conduits interlink any and all components either directly or indirectly. Some of these pipes further comprise valves  51 ,  52 ,  53 ,  54 ,  55 ,  56 ,  57 ,  58 ,  59 ,  60 ,  61 ,  62 ,  63 ,  64 ,  65 , and  66  to limit or stop flow therethrough. As vapors enter transfer pipe  23 , the vapors will travel to valve  51 . Vapors drawn from rotary retort  20  via transfer pipe  23  with specific chemical properties will be retained at one separator  41 ,  42 ,  43 , or  44  while the remaining vapors will continue. As depicted, separator  41  is a condenser operated at 350° C. The majority of vapors entering separator  41  with boiling points above 350° C. will condense to liquid while lower boiling point substances will pass through as vapors. 
     A plurality of valves  51 ,  52 ,  53 ,  54 ,  55 ,  56 ,  57 ,  58 ,  59 ,  60 ,  61 ,  62 ,  63 ,  64 ,  65 , and  66  afford a large degree of flexibility to route vapors to any series of separators  41 ,  42 ,  43 , and/or  44  as desired. Separators  41 ,  42 ,  43 , and  44  represent any number and combination of impingers, condensers, molecular sieves, ion exchange columns, precipitation chambers, reactors, or any of a number of other commercially available vapor and liquid separators known to those skilled in the art. 
     Though vacuum generator  28 , ultimately in communication with and drawing vapors from the rotary retort  20  via transfer pipe  23 , may reduce the pressure to nearly zero pressure absolute, the preferred embodiment and method of use of vacuum generator  28  maintains between 2.25 mm Hg and 735 mm Hg vacuum in all of the apparatus including rotary retort  20 , dryer  7 , if present, heat exchanger  30 , if present, this off-vapor treatment system, and any and all connectors that interlink these components. Though the off-vapor treatment system comprises separators on the vacuum side of the vacuum generator, separators may also be in communication with the system on the outlet or pressure side of the vacuum generator. 
     Vapor compressors  45  and  46  can be operated at different levels of compression and temperature. In fact, in an optimum vapor treatment system, all vapors could be passed through a series of vapor compressors operating at gradually increasing pressures and gradually decreasing temperatures to sequentially condense and separate the vapors into fairly small boiling point range fractions. If high enough pressure and low enough temperatures are used, and the combined vapor and gas volume is very small, even the nitrogen and oxygen can be condensed to liquid. However, attempting to approach the condensation conditions for nitrogen and oxygen will most likely cause all organic substances to condense or solidify. Finally, adsorbents  47 , preferably activated carbon, are typically inserted as a final safeguard to insure that only atmospheric gases, if present, pass through to the atmosphere  48 . 
     This treatment system can be substituted, reconfigured, or otherwise replaced or rearranged except that any vapor compressor,  45  and  46  herein, must be in communication with the system on the “pressure side” or outlet of vacuum generator  28 . As depicted in this embodiment, separator  41  comprises an aqueous impinger, separator  42  comprises an organic impinger, and separator  43  comprises an ice water condenser. Vapor compressors  45  and  46  arc vapor condensers operated at different temperatures and pressure and are preferably used in series. 
     Moreover, the employment of multiple transfer pipes  23   a ,  23   b ,  23   c , and/or  23   d , as depicted in FIG.  2  and discussed herein, can be used in conjunction with this system or similar separation arrangements. In fact, employing a plurality of staggered length transfer pipes  23   a ,  23   b ,  23   c , and/or  23   d  to selectively draw vapors at different points along rotary retort  20  may help decrease the number of separations, thus requiring less separators, that must be performed. 
     As the treated material moves through the end of rotary retort  20 , now unburdened with the volatile substances that have been removed by rotary retort  20 , the treated material passes down retort to heat exchanger pathway  29 . As the treated material enters heat exchanger  30 , preferably a cooling means known to those skilled in the art such as a heat exchanger screw feeder  32  that rotates and moves the treated material along the length of heat exchanger  30 . The outer exterior of heat exchanger  30  comprises heat exchanger spiral gas pathway  31  similar to spiral gas pathways  9  and  19  depicted around dryer  7  and rotary retort  20 . Cooler gases, preferably air from heat exchanger gas entrance  33  enter and travel about heat exchanger spiral gas pathway  31  and exit through heat exchanger gas exit  34  and the hot air goes to burner  12 . In the alternative, heat exchanger  30  may employ a cold water jacket or similar heat exchange means known to those skilled in the art to aid in the cooling of the treated material. 
     Heat contained within the treated material transfers from the treated material to the gases traveling about heat exchanger  30 . By effectively cooling the treated material in this fashion, the treated material will be sufficiently cool at the end of heat exchanger  30  to allow the use of elastomeric pinch valves  35  and  36  like the ones depicted as pinch valves  2  and  3 . Pinch valves  35  and  36  forming second airlock chamber  37  are preferably elastomeric pinch valves, thus requiring cooling of treated materials by heat exchanger  30  and/or supplemental cooling of the pinch valves  35  and  36 . The vacuum may be maintained by a vacuum generator or similar pressure reducer, in communication with the vacuum port  38 , that preferably further comprises a particulate filter on its pressure or output side. Though many particulate filters are known in the art, a high efficiency particulate air filter (HEPA) is preferred. 
     By using alternative pinch valves, the use of heat exchanger  30  may not be necessary. For example, the use of metal valves in the place of pinch valves  35  and  36  may withstand higher heat. In the preferred embodiment, however, by cooling the treated material with heat exchanger  30 , elastomeric pinch valves  35  and  36  can provide a more efficient seal and thus reduce the influx of air and more efficiently maintain the reduced pressure environment of the system as depicted in FIG.  1 . Heat exchanger  30  also recovers the heat from the treated material. Moreover, the present invention and its method of use may include the introduction of water or similar cooling substances to cool the treated material prior to interaction with the airlock, most preferably elastomeric pinch valves. A cool water jacket or similar heat exchange means surrounding the pinch valve can be used to lower the temperature of the pinch valves sufficiently to permit the use of elastomeric pinch valves. The same technology can be used to lower the temperature of the seals at the interfaces of the rotating and non-rotating components to permit the use of elastomeric seals. 
     As the treated material is ushered along the length of heat exchanger  30 , preferably by a rotary heat exchanger, the treated material drops from heat exchanger  30  to exit airlock pathway  39  and collects above pinch valve  35 . Prior to opening pinch valve  35  to allow the treated material to collect within airlock compartment  37 , vacuum as low as zero pressure absolute is drawn on airlock  37 . The gases withdrawn from airlock  37  are typically filtered, preferably with the high efficiency particulate air filter previously discussed, before being expelled into the atmosphere. Once airlock  37  is evacuated of gases, pinch valve  35  is opened and airlock  37  is filled with falling, treated material. Pinch valve  35  closes and pinch valve  36  may be opened to allow the treated material to exit from the system. 
     Returning to the gas pathways, the now heated air exiting heat exchanger gas exit  34  may be heated and directed to burner  12 . Additionally, numerous other methods of heating and cooling the treated material to produce the same results will be evident to those skilled in the art such as spraying cool water on the treated material to cool and rehydrate the treated material. 
     Though the preferred method and embodiment comprise the use of dryer  7  and heater exchanger  30 , these components are optional. Moreover, the addition of components to aid in the separation and collection process, for example the use of heat insulating tape about transfer pipe  23  to insure vapors remain in the vapor phase until off-vapor treatment and collection is possible, fall well within the scope of providing a continuous process for the removal of volatile from nonvolatile substances as depicted herein. Additionally by example, the altering of the chemical composition of the material to be treated with chemical additives may enhance the efficiency of the system by changing the chemical properties of one or more substances leading to more efficient capture and separation. By providing a system that offers versatility and compactness, the present invention provides the method and apparatus capable of significantly reducing processing costs and capturing virtually all of the emissions of substances of concern. 
     An example of the alternatives that are within the scope of the invention is an alternative configuration for at least one airlock. For example as shown in FIG. 4, an airlock  40  is included in the front end  41  of either a continuous rotary retort apparatus or a dryer or similar heat exchanger disposed before the retort. During processing, the vacuum hopper  42  includes valve  43  such as a slide gate inserted or otherwise disposed such that a vacuum tight piston  44  may be isolated from the rest of the hopper  42 . In FIG. 4, piston  44  is in a retracted position as compared to the extended position as shown in FIG.  5 . 
     Piston  44  pushes an auger  45  or similar material transfer device known to those skilled in the art at least partially into the front end  41 , which may be a dryer or a retort, such that the piston head  46  may at least partially clear the valve  43  capable of isolating the vacuum hopper  42  from the auger assembly  45 . As shown, front end  41  may include an interface with wall  47  such as a ring seal  41   a  or similar junction between rotating and non-rotating components of the present invention. When in the position shown in FIG. 5, the piston head  46  and a second piston head  50  form vacuum tight seals to the wall  47  such that virtually no air may escape into the front end  41 . It is envisioned that this function may be improved by incorporating at least one inflatable head piston in either or both of these piston heads to help maintain the seal by producing a vacuum tight seal with the wall  47 . 
     Similarly, it is envisioned that a similar airlock may be configured after the retort. As shown in FIG. 6, an airlock  60  is formed in hopper  61 . At the top of hopper  61 , nearest the end  62  of cooler or retort, a valve  63 , such as a vacuum tight valve, may seal the system from the introduction of ambient pressure into the end  62  of the retort or cooler. A second valve  64 , such as a vacuum tight valve, is secured or otherwise disposed at the bottom of hopper  61  to form airlock  60 . A vacuum pump  65  may be in communication with airlock  60  to maintain the pressure level of the system. In operation, materials being emptied from the end  62  will fall through an open valve  63  and fall into hopper  61 , collecting upon closed valve  64 . As hopper  61  is nearly full, valve  63  will be closed and valve  64  will be opened, allowing the materials to fall into an ambient pressure storage container  66  disposed below the hopper  61 . Once hopper  61  has emptied, valve  64  is closed, vacuum pump  65  evacuate the air that has entered airlock  60 , and valve  63  may be reopened without introducing ambient pressure into the system. 
     Referring to FIGS. 4 and 5, in a preferred method of using airlock  40 , the vacuum hopper  42  may be brought to atmospheric pressure by at least partially opening a vacuum tight valve  48  secured or otherwise disposed on the top of the hopper  42 . In use, the hopper  42  is unsealed as described and may be rapidly filled. Once the vacuum hopper  42  is filled, the vacuum tight valve  48  at the top of the hopper  42  is closed and the air removed with a vacuum pump  49  as described herein until the pressure within the vacuum hopper  42  approximates that of the processing system. The vacuum tight piston  44  is retracted to its original position, pulling the auger  47  back out of the front end  41 , and into its home position. The valve  43  may be opened and the auger  47  begins to feed the waste into the front end  41  of the dryer or retort. This process is repeated when the vacuum hopper  42  is empty. This configuration creates an airlock  40  that can periodically be partitioned or isolated into at least two areas in which different pressures can be established. 
     An alternative embodiment for airlock  40  is shown in FIG.  7 . This airlock  40  may be included in the front end  41  or rear end (not shown) of the continuous rotary retort apparatus. As described herein, the inclusion of a ring seal  41  a or similar seal at the junction of the rotating and non-rotating components of the present invention is preferable. During processing, the vacuum hopper  42  includes valve  43  such as a pinch valve inserted or otherwise disposed such that a material transfer device such as a worm pump, conveyor, auger, screw feeder, or similar device known to those skilled in the art may operate below valve  43 . This configuration allows this material transfer device to be isolated from the hopper  42  prior to opening valve  48  to receive additional material to be treated. Those skilled in the art will recognize that material transfer device  45  may be driven, turned, or otherwise activated by any motor, engine, or similar activating device that may be attached, secured, otherwise place in mechanical communication with material transfer device  45 . The connection point  70  should be sealed or otherwise isolated to insure that the pressure integrity of the system is maintained. Plugs, seals, or similar devices may be in vacuum tight communication with the wall  47  at point  70  to aid in maintaining this integrity. 
     Material transfer device  45  may be configured to translate into front end  41  (or rear end) to aid in the movement of material to be treated or the removal of treated material if included at the rear end (not shown). As previously discussed, an airlock of this configuration benefits from a vacuum generator  49  to help maintain the pressure of the system in airlock  40 . Though described with relation to transferring material to be treated, this device is equally useful on material that has been treated and is being removed from the system. 
     Though this disclosure describes the preferred embodiment and its method of use, it will be evident to those skilled in the art that many modifications in the above-described preferred embodiment of the apparatus and method of its use may be incorporated to provide a system and method of use within the scope and vision of inventive concepts herein.

Technology Category: b