Abstract:
Generally, the present disclosure is related to systems and methods for separating hydrocarbons and/or other liquids from drill cuttings material. One illustrative embodiment disclosed herein is directed to a system that includes, among other things, a thermal reactor that is adapted to remove liquid from drill cuttings material by heating the drill cuttings material to at least a first temperature that is sufficiently high enough to vaporize the liquid. The illustrative system also includes a feeder system that is adapted to controllably feed a flow of the drill cuttings material to the thermal reactor, and a control system that is adapted to control the flow of the drill cuttings material from the feeder system so as to maintain a temperature in the thermal reactor at or above the first temperature.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 12/228,670, filed Aug. 14, 2008, now abandoned which is incorporated fully herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Generally, the present disclosure relates to systems and methods for separating hydrocarbons and/or other liquids from the drill cuttings material from a wellbore being drilled in the earth, and, in certain particular aspects, to such systems and methods which employ a feed apparatus for feeding drilled cuttings material to a thermal reactor. 
     2. Description of the Related Art 
     The prior art discloses a variety of systems and methods for the thermal treatment of material and thermal treatment of drilled cuttings material. For example, and not by way of limitation, the following U.S. patents present exemplary material treatment systems: U.S. Pat. Nos. 5,914,027; 5,724,751; and 6,165,349—all these patents incorporated fully herein for all purposes. 
     SUMMARY OF THE INVENTION 
     The following presents a simplified summary of the present disclosure in order to provide a basic understanding of some aspects disclosed herein. This summary is not an exhaustive overview of the disclosure, nor is it intended to identify key or critical elements of the subject matter disclosed here. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later. 
     The present invention, in certain aspects, discloses a thermal treatment system for removing liquid from drill cuttings material, the thermal treatment system having a metering screw apparatus for receiving and feeding drill cuttings material to a reactor system, including apparatus and a control system for controlling the metering screw apparatus and for insuring that the metering screw apparatus is maintained full or nearly full of material and/or for controlling the mass flow rate into a reactor of the thermal treatment system by adjusting the speed of the metering screw apparatus. 
     The present invention, in certain aspects, discloses a thermal treatment system for treating drill cuttings material in which apparatus and a control system are provided to maintain an airlock at a material inlet to a thermal reactor of the thermal treatment system by maintaining a desired amount of material in a container above a feeder system that feeds material into the thermal reactor. In one aspect in such a system apparatus and a control system provide for control of temperature in the thermal reactor by controlling the mass flow rate of material into the thermal reactor by controlling a metering screw system that feeds material into the thermal reactor. 
     One illustrative embodiment disclosed herein is directed to a system that includes, among other things, a thermal reactor that is adapted to remove liquid from drill cuttings material by heating the drill cuttings material to at least a first temperature that is sufficiently high enough to vaporize the liquid. The illustrative system also includes a feeder system that is adapted to controllably feed a flow of the drill cuttings material to the thermal reactor, and a control system that is adapted to control the flow of the drill cuttings material from the feeder system so as to maintain a temperature in the thermal reactor at or above the first temperature. 
     Also disclosed herein is a thermal treatment system that includes a thermal reactor that is adapted to remove liquid from drill cuttings material, a feeder system that is adapted to controllably feed a flow of the drill cuttings material to the thermal reactor; and a control system that is adapted to control the feeder system so as to increase the flow of the drill cuttings material to the thermal reactor when a temperature in the thermal reactor decreases. 
     Another illustrative thermal treatment system disclosed herein includes, among other things, a thermal reactor having a plurality of rotatable friction elements, wherein the thermal reactor is adapted to remove liquid from drill cuttings material. The thermal treatment system also includes an engine that is adapted to controllably rotate the plurality of rotatable friction elements, wherein the plurality of rotatable friction elements are adapted to generate heat during the controllable rotation. Furthermore, the thermal treatment system is made up of a feeder system that includes a metering screw apparatus and a container positioned above the metering screw apparatus, wherein the container is adapted to receive the drill cuttings material and the feeder system is adapted to controllably feed a flow of the drill cuttings material to the thermal reactor. Additionally, the thermal treatment system includes a control system that is adapted to control the feeder system so as to increase the flow of the drill cuttings material to the thermal reactor when a temperature in the thermal reactor decreases, and to decrease the flow of the drill cuttings material to the thermal reactor when the temperature in the thermal reactor increases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which: 
         FIG. 1A  is a schematic view of a system according to the present invention; 
         FIG. 1B  is a top view of the system of  FIG. 1A ; 
         FIG. 1C  is a partial side view of part of the system of  FIG. 1A ; 
         FIG. 1D  is a cross-section view of a feeder system of the system of  FIG. 1A ; 
         FIG. 1E  is a cross-section view of a feeder system useful in a system like the system of  FIG. 1A ; 
         FIG. 1F  is a cross-section view of a container of a feeder system according to the present invention; 
         FIG. 2A  is a side cross-section view of a feeder system according to the present invention; 
         FIG. 2B  is an end view of the system of  FIG. 2A ; 
         FIG. 2C  is a top view of the system of  FIG. 2A ; 
         FIG. 2D  is a top view of part of the system of  FIG. 2A ; 
         FIG. 2E  is an end view of a slide of the system of  FIG. 2A ; 
         FIG. 3  is a top view of a system according to the present invention; 
         FIG. 4  is a schematic view of a system according to the present invention; 
         FIG. 5  is a schematic view of a system according to the present invention; 
     
    
    
     While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     Various illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase. 
       FIGS. 1A-1D  illustrate a system  10  according to the present invention which has a thermal reactor section  12  and a feeder system  40  according to the present invention. Drill cuttings material M is fed from the feeder system  40  into a reactor vessel  14  (mounted on supports  18 ) of the thermal reactor section  12  through an inlet  13 . Treated material exits the vessel  14  through a discharge outlet  15 . An engine section  16  has an engine  17  that rotates internal rotors (or friction elements)  8  in the vessel  14 . The vessel  14  has, optionally, a plurality of inlets  7  into which drill cuttings material for treatment can be fed. Load cell apparatuses  3  in communication with a control system CS indicate the amount of material in the vessel  14 . 
       FIGS. 1C and 1D  illustrate the feeder system  40  which has a base  42  with sides  44 ,  44   a , and  44   b , and a bottom  45  within which is mounted a container  46  for holding drill cuttings material to be fed to the vessel  14 . It is within the scope of the present invention to have a container  46  with a substantially horizontal level bottom with a metering screw system beneath it which is also substantially horizontal; or, as shown in  FIG. 1D , the container  46  has an inclined bottom  48  with a trough  47  and a metering screw system  60 , which receives material from the container  46 . The system  60  inclined to correspond to the incline of the bottom  48 . Material falls into a trough  47  at the bottom of the container  46  (in which a screw  62  of the system  60  is located). The bottom of the container  46  may be any suitable shape to facilitate the flow and movement of material to the system  60 ; e.g. as shown in  FIG. 1F , walls  46   w  of a container  46   a  are inclined above a trough  47   a.    
     Drill cuttings material from a wellbore drilling operation indicated by an arrow  49  is fed by an auger apparatus  50  through an inlet  51  into the container  46 . The drill cuttings material may come from any suitable apparatus or equipment, including, but not limited to, from shale shaker(s), centrifuge(s), tank(s), cuttings storage apparatus, vortex dryer(s), hydrocyclone(s), or any solids control equipment that produces a stream or discharge of drill cuttings material. 
     Optionally drill cuttings material is introduced into the container  46  through a line  53  from a system  54  (not directly from drilling operation equipment, like shale shakers or centrifuges) that transfers and/or transports drill cuttings material (e.g., but not limited to, the known BRANDT FREE FLOW (TRADEMARK) cuttings transfer and transportation system). Optionally, the material is fed to a vortex dryer VD for processing and the solids output of the vortex dryer is fed to the container  46 . 
     A valve assembly  56  is used to selectively control the flow of free flowing material (e.g. liquids) from the system  60  into the vessel  14  as described below. Such liquids are not moved so much by the screw  62  as they flow freely past the screw  62  to the valve  56  through the system  60 . 
     Optionally, (especially for material that may be easily compacted) if additional lubricant is needed for the material to be introduced into the vessel  14 , the lubricant is injected into material in the system  60  through injection ports or nozzles  57  from a lubricant system  58  (e.g., but not limited to, a lubricant that is base oil, an oil component of a drilling fluid). In one aspect, if a load on a motor  52  which rotates the screw  62  (e.g. an hydraulic motor) is increased beyond a pre-selected set point, lubricant is injected through the nozzles  57  to facilitate material flow within the system  60  and lessen the load on the motor  52 . 
     Optionally, a pump  70  in fluid communication with the interior of the container  46  pumps free liquid from within the container  46  to reduce the liquid content of the material. This can optimize the performance of the system by insuring that the feed to the vessel  14  has a reduced amount of free liquid. Optionally, as shown in dotted line in  FIG. 1D , a pump  70   a  may be located within the container  46  (in one aspect, in the material M). 
     As shown in  FIG. 1E , a conveyor apparatus for conveying material to a vessel like the vessel  14  can have a constant pitch screw  62   s ; or, as shown in  FIG. 1D , the screw  62  of the system  60  has areas of different pitch, e.g. areas  62   a ,  62   b , (with the tightest pitch at the end near the motor  52 ) and  62   c  which reduce the likelihood of material compaction in the system  60  and facilitates material flow in the system  60 . In one particular aspect, the system  60  is about ten inches in diameter; the container  46  has a volume of about eighteen cubic meters; and the bottom  45  is about four meters long. In certain aspects, the container  46  has therein, at any given time, between three to sixteen cubic meters of material and, in one particular aspect, about sixteen cubic meters. The screw may have two, four or more areas of different pitch. 
     In one aspect, during operation of the system  10 , an amount of material is maintained in the container  46  (e.g. in one aspect, a minimum of about three cubic meters) so that an “airlock,” or sealing condition, may be created and substantially maintained at the inlet  13 , thereby substantially preventing ingress of oxygen into the vessel  14 . Additionally, by using the control system CS described below to ensure that a sufficient amount of material is maintained within the vessel  14 , an airlock, or sealing condition, may also be created and substantially maintained at the discharge outlet  15  of the system  12 . For example, in some illustrative embodiments, the system  10  may include a hopper (not shown) at the discharge outlet  15 , and the control system CS may be adapted to control the flow of drill cuttings material through the vessel  14  such that a sufficient level of material is present in the hopper so as to thereby create and/or substantially maintain the previously described airlock condition at the outlet  15 . In certain embodiments, the hopper (not shown) at the discharge outlet  15  may be, for example, a substantially vertically oriented pipe and the like, or a similar type of structure in which an appropriate level of drill cuttings material may be maintained. Furthermore, in at least some embodiments, the hopper (not shown) may include a level detection system, such as a level sensor and the like, which may provide information to the control system CS regarding the level of drill cuttings material in hopper, thereby enabling additional control of the airlock condition at the discharge outlet  15  as noted above. 
     Load cell apparatuses  72  (one, two, or more) indicate how much material (by weight) is in the container  46 . This correlates with the level of the material so that, as shown in  FIG. 1C , a level “a” can be maintained indicative of the volume of material sufficient to maintain the airlock at the inlet  13  described above. The load cell(s) is also used with the control system CS to calculate the rate of metering of material into the vessel  14  and to set and control maximum and minimum levels of material in the container  46 . In one aspect the level “a” is between 50 mm and 1000 mm and, in one particular aspect, is 500 mm. Optionally, or in addition to the load sensor(s)  72 , a level indicating apparatus  79  is used to obtain data to determine the amount of material in the container  46  and its level. In one aspect, the apparatus  79  is an ultrasonic distance measuring apparatus. 
     Personnel P can, optionally, remove free liquid from the top of material in the container  46  (e.g. from the top thereof) by manually placing an end  75   a  of a pipe  75  within a conduit  77  connected to the container  46  to pump free liquid (e.g. drilling fluid and some water, inter alia); from the container  46  thereby reducing the liquid content of material introduced into the vessel  14 . In one aspect the pipe  75  is connected to the pump  70 ; or some other pump is used. In one aspect a pump system is placed within the container  46 . 
     A control system CS controls the various operational parts and apparatuses of the system  10  as shown schematically in  FIGS. 1A ,  1 B, and  1 D. In particular aspects, the control system CS receives information from the load cell(s)  72 , and from sensors  2  on the engine  17  (e.g. torque and/or speed in rpm&#39;s) and from sensor(s)  52   a  on the motor  52  (e.g. motor speed in rpm&#39;s). The control system CS controls the operation of the engine  17 , the motor  52 , the valve  56 , the auger apparatus  50 , the system  60 , the system  58 , the system  54 , the pump  70 , and an hydraulic power supply HPP which supplies power to the motor  52  and any other hydraulically powered item. In one aspect, sensing of the load on the motor  52  is done using a pressure sensor  52   a  (shown schematically). In one aspect, thus monitoring the pressure of hydraulic fluid applied to the motor  52  provides the information needed to activate the injection of additional lubricant via the nozzles  57 . Via sensing of the temperature within the vessel  14  (using a sensor or sensors; e.g., in one aspect three sensors along the top of the vessel  14 ), the control system CS maintains the flow of material into the vessel  14  by controlling the system  40  at a sufficient rate such that the temperature within the vessel  14  is maintained at a sufficiently high level to effectively heat the drill cuttings material so that most, or substantially all, of any liquid phase(s) present in the material may be vaporized, however without exceeding a pre-defined maximum temperature—i.e., within an optimal temperature range. 
     For example, in certain illustrative embodiments, when the control system CS detects a temperature drop within the reactor vessel  14 , it may be indicative that there is insufficient drill cuttings material inside of the vessel  14  to interact with the rotating friction elements  8  so as to thereby maintain the temperature at a sufficiently high level, as previously described. Accordingly, the control system CS may operate to control the feeder system  40  in such a manner as to increase the flow of drill cuttings material to the reactor vessel  14 , thereby ensuring that there is sufficient drill cuttings material in the vessel  14  to interact with the friction elements  8 , and so that the temperature within the vessel  14  may be substantially maintained above a pre-defined minimum value. On the other hand, when the control system CS detects a temperature increase within the reactor vessel  14 , it may be indicative that, for example, the amount of drill cuttings material inside of the vessel  14  may be too great, or that the composition of the drill cuttings material being fed into the container  46  of the system  60  may have changed. In such circumstances, the control system CS may also operate to control the feeder system  40  so as to decrease the flow of drill cuttings material to the reactor vessel  14 , thereby enabling the temperature within the vessel  14  to be controlled so that it is substantially maintained below the pre-defined maximum value, as noted above. 
     In various embodiments of the thermal treatment system disclosed herein, the motor  52 , engine  17 , pump  70  and/or other powered items in these systems can be powered electrically, pneumatically, or hydraulically. 
     In certain particular aspects, the oil content of feed into the container  46  is maintained between 15% to 30% by weight and the water content is maintained between 8% to 20% by weight. 
     In other aspects, the solids content of the material introduced into the container  46  is, preferably, at least 70% solids by weight; and the liquid content of the material fed into the vessel  14  is 30% or less (liquid includes oil and water). A pump or pumps (e.g., but not limited to, the pump  70 ) reduces (and, in certain aspects, minimizes) the amount of free liquid fed to the vessel  14 . If too much liquid is fed into the vessel  14 , undesirable “wash out” may occur, a sufficient amount of solids will not be present, and, therefore, sufficient friction will not be developed to achieve a desired temperature within the vessel  14  for effective operation. In certain aspects, and depending on the specific of the material content of the solids and/or liquid phase(s), the temperature within the vessel  14  may be maintained by the control system CS between a pre-defined minimum value of approximately 250 degrees Centigrade and a pre-defined maximum value of approximately 400 degrees Centigrade. 
     It is also desirable for efficient operation that the engine  17  operate at an optimal loading, e.g. at 95% of its rated capacity. If the control system CS learns, via a speed sensor  2  on the engine  17  that the RPM&#39;s of the engine  17  are dropping off from a known maximum, this may indicate too much material is being fed into the vessel  14 . The control system CS then reduces the mass transfer rate into the vessel  14  (by controlling the system  60 ). Power generated typically drops off as the RPM&#39;s drop off, as can be seen on a typical performance curve. Insuring that the power generated is maximized provides the maximum energy available to generate the heat required within the vessel  14 . 
     Initially at start up, in one aspect, the valve  56  is opened slowly. As free flowing liquid and material flow into the vessel  14 , the temperature is maintained. If there is no dramatic drop in temperature, this indicates that the flow of material has an appropriate liquid content so that a desired operational temperature and effective operation can be achieved. Then the valve  56  is fully opened as the system  60  is controlled by the control system CS and full flow commences. 
     The container  46  may be filled continuously or in batches. 
       FIG. 1E  shows a system  10   a , like the system  10  described above, and like numerals indicate like parts. The initial feed of drill cuttings material to the container  46  is from one or more shale shakers SS (or other processing equipment) whose drill cuttings material output (e.g. off the tops of the shaker screens or from a centrifuge) is fed to a buffer apparatus BA to maintain a desired liquid content of the material in the container  46 , and, in one aspect, to minimize this liquid content. The buffer apparatus BA can be any suitable system or apparatus; e.g., but not limited to: a system according to the present invention (e.g., but not limited to a system as in  FIG. 1A ,  2 A, or  3 ); a storage system for drill cuttings material; a skip system; a cuttings containment and transfer system (e.g., but not limited to, a known system as disclosed in U.S. Pat. No. 7,195,084, co-owned with the present invention); or a transfer/transport system, e.g., but not limited to, the BRANDT FREE FLOW (TRADEMARK) systems. 
       FIG. 2A  shows a system  10   b  like the system  10  described above and like numerals indicate like parts. 
     The system  10   b  has a slider system  80  with a slider frame  82  selectively movable by a piston mechanism  84  with one part connected to the slider frame  82  and controlled by the control system CS. Power for the piston mechanism  84  is provided by an hydraulic power pack HPP (which also provides power to the motor  52 ). The slider frame  82  moves material on the bottom  48  of the container  46  to facilitate the flow of material down to the screw  62  of the system  60 . A slider frame may be used as shown in U.S. Pat. No. 7,195,084. 
     The slider frame  82  has a central beam  86 , and, optionally, beveled end edges  88 . The slider frame  82  moves material facilitating its entry into a trough  47  in which is located the screw  62 . Optionally, the slider frame  82  is smaller than shown with no central beam  86  and is movable to and from the trough  47  on both sides thereof. 
       FIG. 3  illustrates a system  10   c , like the system  10 , and like numerals indicate like parts The reactor section  12   c  has multiple material inlets  13   c  into which material is introducible into a vessel  14   c . One feeder system may be used at one inlet  13   c  or multiple feeder systems  40   c  may be used (three shown in  FIG. 3 ). 
       FIG. 4  illustrates improvements to systems of U.S. Pat. No. 5,914,027 (fully incorporated herein for all purposes) and shows a system  200  with a feeder system  210  (like any feeder system disclosed herein according to the present invention) which feeds material into a reactor chamber or vessel  201  with a rotor  202  including friction elements  203 . The rotor  202  further includes a shaft  204  sealed in the reactor with mechanical seals  205 . The friction elements  203  are pivotably mounted in rotor plates  207  (as in U.S. Pat. No. 5,914,027). Each pair of adjacent rotor plates  207  carries a number of friction elements  203 . The friction elements  203  are staggered relative to each other. The staggered arrangement may achieve turbulent action in a bed of grained solids in the vessel. The friction elements  203  are pivotably mounted in between adjacent rotor plates  207  by rods extending over the length of the rotor  202  (as in U.S. Pat. No. 5,914,027). 
     The rotor  202  is driven by a rotating source  209  which can be an electrical motor, a diesel engine, a gas or steam turbine or the like. The material is brought to the reactor from the feeder system  210  via a line  211 . Water and/or oil (e.g., base oil) can be added to the flow from the pipe  212 . Cracked hydrocarbon gases (and, in one aspect, over-saturated steam) leaves the reactor via a line  213  and, in one aspect, flows to a cyclone  214  and proceed to a condenser unit  215  which can be a baffle tray condenser, a tubular condenser or a distillation tower. The different fractions of the oil can be separated directly from the recovered hydrocarbon gases. The heat from condensation is removed by an oil cooler  216  cooled either by water or air. The recovered oil is discharged from the condenser by a pipe  217  to a tank  218 . 
     Solids leave the reactor via a rotating valve  219  and a transport device  220  which can be a screw or belt conveyor or an air transportation pipe system to a container  221 . The solids separated from the cyclone  214  are transported via a rotating valve  222  to the container  221  either by being connected to the transport device  220  or directly to the container  221  by a cyclone transport device  223 . 
     In certain illustrative embodiments, a control system, such as the control system CS of the thermal treatment system  10  shown in  FIGS. 1A-1D  above, may control the rotating valve  219  so that an airlock condition may be created and/or substantially maintained at the discharge outlet of the reactor vessel  201 , as previously described. Furthermore, in certain embodiments the rotating valve  219  may also be controlled by the control system so as to permit an increased flow of material from the reactor vessel  201  when, for example, the control system detects a reduction in the rotational speed of the rotating source  209 , which, as previously described regarding the thermal treatment system  10  above, may be an indication that too much material is present in the reactor vessel  201 . 
     Non-condensable gases exit in a pipe  224  and can flow from the pipe  224  to a filter unit or to a flare tower or are accumulated in a pressure tank—not shown. The system  200  may be operated in any way described in U.S. Pat. No. 5,914,027. The items downstream of the vessel  201  may be used with any system according to the present invention. 
       FIG. 5  illustrates that the present invention provides improvements to the systems and methods of U.S. Pat. No. 5,724,751 (fully incorporated herein for all purposes) and shows a system  300  according to the present invention with a process chamber with a rotor  302  and blades  303  driven by an engine  304 . A mass of material is fed into the process chamber (as indicated by feed arrow  305 ) by a feeder system  320  (any feeder system disclosed herein according to the present invention). The mass in the process chamber is whipped by the blades and subjected to energy or vibrations from the said blades and ribs  308 , which are sufficiently closely spaced to each other to cause turbulence during the rotation of the blades. Additional energy may be supplied in some form of heated gas from a combustion engine  309 . Gases, mist and vapors leave the process chamber  301  via an output opening via a vent fan  311  and on to either open air or to a condenser. Dried material is led through an output opening  312  via a rotating gate  313 . The system  300  may be operated in any way described in U.S. Pat. No. 5,724,751. The items downstream of the process chamber of the system  300  may be used with any system according to the present invention. 
     The present invention, therefore, provides in some, but not in necessarily all, embodiments a thermal treatment system for removing liquid from drill cuttings material, the thermal treatment system having a metering screw apparatus for receiving and feeding drill cuttings material to a reactor system, including apparatus and a control system for controlling the metering screw apparatus and for insuring that the metering screw apparatus is maintained full or nearly full of material and/or for controlling the mass flow rate into a reactor of the thermal treatment system by adjusting the speed of the metering screw apparatus. 
     The present invention, therefore, provides in some, but not in necessarily all, embodiments a thermal treatment system for treating drill cuttings material in which apparatus and a control system are provided to maintain an airlock at a material inlet to a thermal reactor of the thermal treatment system by maintaining a desired amount of material in a container above a feeder system that feeds material into the thermal reactor. 
     Any system according to the present invention may include one or some, in any possible combination, of the following: wherein apparatus and a control system provide for control of temperature in the thermal reactor by controlling the mass flow rate of material into the thermal reactor by controlling a metering screw system that feeds material into the thermal reactor; wherein the thermal treatment system has an engine that rotates friction elements within a reactor vessel of the thermal reactor and performance of said engine is optimized by controlling a metering screw system that feeds material into the reactor vessel (e.g., based on sensed speed in rpm&#39;s of said engine); a sensor or sensors or at least one load cell apparatus or two load cell apparatuses beneath the container to provide information to indicate an amount of material in the container; a sensor or sensors or at least one load cell apparatus or two load cell apparatuses beneath the thermal reactor to provide information to assist in control of the discharge rate of solids from the thermal reactor; wherein a control system controls the amount of material in the thermal reactor; wherein the control system controls said amount to maintain an airlock at the discharge from the thermal reactor; apparatus and a control system to maintain a desired temperature in the thermal reactor; a first feed of drilling cuttings material into the container; wherein the first feed is from drilling operations solids control equipment which is at least one of shale shaker, centrifuge, vortex dryer, and hydrocyclone; wherein the first feed is from a cuttings conveyance system; a secondary feed into the container from a cuttings storage or transfer system; and/or apparatus and a control system for control of temperature in the thermal reactor by controlling the mass flow rate of material into the thermal reactor by controlling a metering screw system that feeds material into the thermal reactor; the thermal treatment system having an engine that rotates friction elements within a reactor vessel of the thermal reactor and performance of said engine is optimized by controlling a metering screw system that feeds material into the reactor vessel (e.g., based on sensed speed in rpm&#39;s of said engine); at least one load cell apparatus or two load cell apparatuses beneath the container to provide information to indicate an amount of material in the container. 
     The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the method steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.