Patent Application
20100050466
This invention relates generally to an apparatus and method for the heating of liquid and solid mixtures in order to remove volatile constituents therefrom. More particularly, the present invention is directed toward the effective recovery and recycling of heat energy from those same liquid and solid mixtures. Specifically, the invention provides for the recovery and recycling of heat energy by controlling and directing the flow of the liquid and solid mixture, as well as various gases, vaporized liquids and combustion products, within the apparatus, and recovering useful by-products therefrom.
In the processing of hazardous and non-hazardous wastes, such as drilling muds, ship bilge, soils contaminated by oil leaks or spills, tank bottoms, municipal solid wastes and the like, it has been a common practice to simply store the materials in, for example, land fills, lagoons and tanks. It has been long appreciated, however, that such methods of dealing with these materials are unsatisfactory for numerous and self-evident reasons. As a result of this appreciation, many industries have devoted significant time and effort to conducting research for alternative industrial processes that avoid creating the waste materials in the first place, or that limit the production of the waste materials. However, these alternative processes add significantly to the cost of the industrial process, making the overall process less profitable.
As an example, in the extraction of oil and gas from wells, there has been an increase in the use of various polymers, rather than chrome laden sulfonate additives, as widely used in the past. The polymers are more expensive and less effective. Nevertheless, the redeeming value in using these polymers is their ability to be effectively destroyed by incineration. In contrast, chrome-based muds, a known hazardous waste resulting from drilling operations that use chrome additives, when incinerated, not only produce harmful by-products during incineration, such as dioxin and nitrous oxide, but also produce a solid residue that is known to be toxic and to contain leachable metals. Hence, it has been found that destructive procedures for dealing with hazardous waste, such as incineration, are generally expensive and often involve byproducts that, in some circumstances, are as harmful as, or more harmful than, the original wastes.
In another example, materials from tank bottoms, bilge bottoms, and oil-contaminated earth are often incinerated. The incineration process is inherently expensive, because most of these wastes are essentially water. Thus, the wastes must not only be boiled, but also be raised to a proper incineration temperature (1800° F. to 2000° F.) and be held at that temperature for one to two seconds to insure nearly complete combustion. Such a procedure is expensive because additional energy is required to reach the proper temperature. Moreover, it is prone to produce further undesirable by-products as discussed hereinabove, but it also destroys (through oxidation) hydrocarbons that would otherwise be of commercial value if recovered.
Furthermore, disposing of drilling muds is difficult, particularly with known mass volume wet oxidation or even super-critical wet oxidation techniques now being used due, at least in part, to the presence and concentration of metal salts, often in excess of 5000 mg/l. It is well known that these metal salts attack the metal containment vessels used in these techniques and severely damage or destroy the metal containment apparatus of those wet chemistry vessels.
It is also a problem that many wastes are at isolated locations and/or exist in too small quantities to economically warrant a typical fixed base incineration process. As a result, these wastes must be transported at great risk and cost.
There are known processing devices that heat wastes in the absence of oxygen to bake away the hydrocarbons from the water and solids residue, but these devices generally utilize either (1) a batch process or (2) a continuous operation process that provides ineffective methodology or apparatus for the recovery of heat energy. The use of heat energy in the operation is required if the processing device is to be efficiently self sustaining. Such ineffective devices are currently used in the extraction of hydrocarbons from tar sands and oil shales. While these are not wastes per se, their processing is similar in nature to hazardous waste processing except that when compared to most hazardous waste, the sand and shale are usually lower in water and hydrocarbon content percentage to the total solid weight of the materials and the recovery of the hydrocarbon is the primary object of the process.
For example, U.S. Pat. No. 4,280,279 discloses a rotating kiln which introduces feed to an inner drum, wherein outgoing solids pass in counterflow in an exterior, concentric drum. Steam and gases are extracted and condensed separately. This, however, violates the principles of conservation of heat energy in that the coldest materials to be treated are on the interior of the device and the exiting solids, which have the highest temperatures, lose most of their heat to the outside walls of the kiln. No heat energy of the water is conserved at all, nor is the heat energy of the oil extracted. The heat necessary to supply the kiln is derived partially from the combustion of the product itself within the kiln supplemented by a burner discharging into the kiln.
Similarly, U.S. Pat. No. 4,285,773 discloses a cold feed into the interior of a rotating kiln and direct firing within the kiln chamber with extraction of the liquid and oil factions, resulting in the loss of heat therefrom, as well as loss of most of the heat from the solid faction due to its outboard placement.
U.S. Pat. Nos. 4,563,246, 4,583,468 and 4,724,777 all disclose retort devices, which lack the ability of using the heat of vaporization of the liquid water and oil factions to preheat incoming materials. Further, all use peripheral spiral chambers for return flow of solids that are known to often result in flow plugging and poor mixing of the exiting solids as necessary for proper heat extraction.
Therefore, a need exists for a retort apparatus for the baking of a liquid and solid mixture, such as for the processing of hazardous waste, sand tar, oil shale or the like, which has the ability to recover and recycle heat energy, useful by-products, and decontaminated materials from the retort process.
It will, therefore, be appreciated that one aspect of one or more embodiments of the present invention may be to provide a retort apparatus for the baking of liquid and solid mixtures that has a higher thermal efficiency than conventional retort apparatuses. To provide this higher thermal efficiency, in one or more embodiments, the retort apparatus may use the materials entering the apparatus to cool those materials exiting the apparatus. Conversely, in one or more embodiments, the materials entering retort apparatus may be preheated by the materials exiting the apparatus.
One or more other aspects of the invention may be provided by one or more embodiments of a retort apparatus that can recover hydrocarbons impregnated in a liquid and solids mixture, while maintain the high thermal efficiency described above. In one or more embodiments, the recovered hydrocarbons may be used as fuel to provide or augment the fuel needs of the process.
In one or more embodiments, another aspect of the present invention may be achieved by providing a retort apparatus that is capable of recovering liquid produced by the combustion of fuel in the process. In one or more other embodiments, useful by-products and useful decontaminated materials from the retort may be recovered.
In yet one or more other embodiments, an aspect of the invention may be provided by a retort apparatus, that is capable of supplying at least a portion of its own energy needs to facilitate making the apparatus mobile while still retaining its efficiency.
It is a still further aspect of the present invention to provide a method for the processing of liquid and solid mixtures to extract the liquid from the solid.
One or more of these aspects of the present invention, which will become apparent from the description to follow, are accomplished by the improvements hereinafter described and claimed.
In general, the present invention provides a retort apparatus for baking liquid and solid mixtures with the release of gases or vaporized liquids, and extracting and recycling heat energy from waste materials separated therein, includes a plurality of concentrically nested pipes, each pipe having a first end and a second end, an inner and an outer surface, and a substantially common longitudinal axis. The nested pipes include a first rotating pipe within a second rotating pipe which is positioned within a fixed pipe. The first and second rotating pipes are independently rotatable, in both speed and direction, about the substantially common longitudinal axis. An interior area of the first rotating pipe is bounded by the inner surface thereof. A first annulus is formed between the first and second rotating pipes, and a second annulus is formed between the second rotating pipe and the fixed pipe. A heating device or heater is positioned proximate the second end of the first rotating pipe and within the interior area thereof. A gate is provided for introducing the liquid and solid mixture into the first annulus proximate the first end of the second rotating pipe. A first conveyance is provided to move the liquid and solid mixture within the first annulus in a direction toward the second end of the first rotating pipe. A second conveyance is provided for transferring the liquid and solid mixture from the first annulus to the interior area of the first rotating pipe. A third conveyance is provided to move the liquid and solid mixture within the interior area of the first rotating pipe in a direction toward the first end of the first rotating pipe.
There is also provided according to the invention a method of retorting a liquid and solid mixture with the release of gases or vaporized liquids and extracting and recycling heat energy from materials separated therein, which includes the steps of introducing the liquid and solid mixture into the first annulus proximate the second end of the second rotating pipe, causing the liquid and solid mixture to move within the first annulus in a direction toward the first end of the first rotating pipe, and transferring the liquid and solid mixture from the first annulus to the interior area of the first rotating pipe. The method also includes the steps of causing the liquid and solid mixture within the interior area of the first rotating pipe to move in a direction toward the second end of the first rotating pipe.
One schematic representative form of a retort according to the concepts of the present invention is generally indicated by the numeral 4 in
In at least one embodiment, retort 4 includes a plurality of concentrically nested pipes. As shown in various Figures, the nested pipes may include a primary rotating pipe 8, disposed within a second rotating pipe 7, which, in turn, is further positioned within a containment casing pipe 6. Of course, the number of actual pipes employed is not a limitation of the present invention, and any plurality of pipes that will carry out the objects of the invention as discussed herein are within the scope of the invention.
In one embodiment, pipes 8, 7, and 6 are concentrically nested such that the longitudinal axis of each pipe is substantially the same. It will be understood by those skilled in the art that pipes 8, 7, and 6 may be positioned such that each pipe has the exact same longitudinal axis or positioned such that each pipe has an offset longitudinal axis from the others. All such configurations are considered to be within the scope of the present invention, and are all considered to be encompassed by language such as “substantially the same longitudinal axis” and “substantially common longitudinal axis” or the like. For the ease of this disclosure and for exemplary purposes only, the following discussion and the drawings attached hereto, represent pipes 8, 7, and 6 as having exactly the same longitudinal axis.
The primary rotating pipe 8 and second rotating pipe 7 are independently rotatable about substantially the same longitudinal axis. In one embodiment, pipe 8 may match speed and rotation with pipe 7. In one or more other embodiments, pipe 8 may move in the opposite direction of, or at a speed that is greater than or less than the speed of pipe 7, as may be prudent for cleaning and mixing of the materials to be processed. As shown in
Each pipe 8, 7, and 6 has an inner and an outer surface. As best shown in
As best illustrated in
With further reference to
In one embodiment, some treated gasses or fluids may be extracted and collected from the combustion heater 24 and delivered by conduit 37 for use as at treatment container 38 which may be configured to extract and separate, by divergent condensing temperatures or other means, a multiplicity of fluids. The remainder heated fluids and gasses may then be redistributed back to the retort apparatus 4 via conduit 39, where they reenter, between pipe 6 and pipe 7, into annulus 19. Furthermore, the fluids in annulus 19 then move in counter-flow direction to the materials in annulus 9. Again, there fluids aid in pre-heating the materials travelling through annulus 9. Of course, by transferring the heat in these fluids and gasses in annulus 19 to the materials in annulus 9, the fluids and gasses will condense. Baffles 18 divide the containment casing pipe into separate zones of differing temperatures, with the hottest zones proximate to the hot end of the pipes and the coolest zones distal to the hot end of the pipes. Any condensed fluids or liquids cooled below the dew point of targeted heat recovery gasses may exit the device 4 as at outlet 33 for further recovery and use through conduit 30. One or more other conduits, such as conduits 29a, 29b, and 29c, (and there respective outlets) may exist for extracting condensate from the general temperature of that zone of extraction between baffles 18. Any one or more of these conduits, like conduit 30, may carry non-condensed gases to a blower 26. Blower 26 then transfers the gases to a heat exchanger 27, wherein the gases are turned to liquids and received in container 28.
In
In
As can be interpreted from
In
In
A sectional end view of the heating chamber is more particularly shown in
In one embodiment, materials may enter a hopper (not shown) and travel to rotary valve 57 via conduit 56. When the rotary valve 57 is turned so that the seal surface 58 allows the charging chamber 59 to be open at the top, and materials can enter the gate 5. Once the rotary gate valve 57 is opened and has received the mixture to be processed, the valve 57 may then be turned through seal 58 so that the charging chamber 59 is opened to the annulus 9 via conduit 60 as shown in the illustrated position of
In like manner, to dispense with processed materials, the processed materials may enter a conduit 63 from annulus 11, as defined by wall 62. When the rotary valve 66 is turned through seal surface 65 so that the charging chamber 64 coincides with the conduit 63, the flow is opened to materials, and materials enter the sealed rotary gate 13. Then, once the gate is full, the rotary gate valve 66 may then be turned through seal 65 so that the charging chamber 64 is open to a discharge position as shown in the illustrated position of
One skilled in the art will appreciate that the bounds of the heating zone will vary with the heat output of a heater source, as well as with other process conditions. Furthermore, a retort having multiple heater units and hence, multiple heating zones, is within the scope of the invention. For simplicity and for exemplary purposes, the present invention will be described herein as having a singular combustion heater 24 and hence, a singular heating zone.
As the liquid and solid mixture enters the heating zone, the heat from heater 24 in fixed heating tube 14 of
In operation, it will be appreciated that heat energy transferred from components and materials within the interior annulus 11 containing the highest temperature liquid and solid mixture to components and materials in annulus 9 containing generally lower temperature portions of the liquid and solid mixture. Thus, because the higher temperature material is effectively internal of the lower temperature material, heat is not lost as readily to the surrounding environment as with the known prior retort devices. Rather, the heat is transferred to the incoming liquid and solid mixture, effecting an efficient recycle of the heat energy. That is, the incoming liquid and solid mixture is preheated, thus requiring less energy from heating tube 14 to achieve proper baking temperature. However, for even further increased efficiency, if heating tube 14 is of a combustion type, combustible gases from pipe conduit 15, such as various hydrocarbons, released as a result of the baking process discussed hereinabove, may be extracted and used as the fuel for combustion in heating chamber 24 and heating tube 14.
If the retort 4 is employed to remove combustible materials, such as for example, various hydrocarbons, these materials may be removed and stored for further use. It will be appreciated by one skilled in the art that retort 4 is energy self-sufficient to some degree, making it ideally suited, for example, to be transported to the waste material for treating the material, rather than vice versa.
With reference to
Paddles 42, 44 may be made of a laminate construction for strength, such as by providing a base layer of a heat conductive material such as aluminum, supporting a steel layer, and having a nickel interface therebetween. Anti-wear surfaces may also be provided such as those made of Stellite, a chromium-tungsten alloy available from Union Carbide, or Barberite, a suspension of carbide grit in a steel matrix that is usually stainless steel but may employ other metals depending upon the supporting metal, e.g., using a layer of nickel if the base is aluminum with Barberite over the nickel. Such surfaces may be shown as 73 and 74 on paddle 42.
In
To effect rotation of first and second rotating pipes 8 and 7, any conventional technique and apparatus may be employed. For example, one method has been shown above in
Thus it should be evident that the device and methods of the present invention are highly effective in conserving heat energy in a retort for the processing of liquid and solid mixtures. The invention is particularly suited for processing of hazardous waste sludge, oil shale, and the like, but is necessarily limited thereto. The device and method of the present invention can be used separately with other equipment, methods and the like, as well as for the separation of other materials in addition those exemplified hereinabove. Based upon the foregoing disclosure, it should now be apparent that the use of retort 4 described herein will carry out the objects set forth hereinabove. It is, therefore, to be understood that any variations evident fall within the scope of the claimed invention and thus, the selection of specific utilization of retort 4, its operating conditions and the like, can be determined without departing from the spirit of the invention herein disclosed and described. Thus, the scope of the invention shall include all modifications and variations that may fall within the scope of the attached claims.
