PRODUCED IN THE DRILLING OF WELLBORES

The present invention relates to an apparatus and method for facilitating separation of hydrocarbons from hydrocarbon laden drill cuttings produced in the drilling of a wellbore .

In the drilling of a borehole in the construction of an oil or gas well, a drill bit is arranged on the end of a drill string and is rotated to bore the borehole. A drilling fluid known as "drilling mud" is pumped through the drill string to the drill bit to lubricate the drill bit. The drilling mud is also used to carry the cuttings produced by the drill bit and other solids to the surface through an annulus formed between the drill string and the borehole. The drilling mud contains expensive synthetic oil-based lubricants and it is normal therefore to recover and re-use the used drilling mud, but this requires the solids to be removed from the drilling mud. This is achieved by processing the drilling fluid. The first part of the process is to separate the solids from the solids laden drilling mud. This is at least partly achieved with a vibratory separator, such as those shale shakers disclosed in US 5,265,730, WO 96/33792 and WO 98/16328. Hydrocyclones and centrifuges may also be used to separate the drill cuttings from the drilling mud.

The separated solids are contaminated with hydrocarbons from the drilling mud or from natural oils in the formation being drilled. The solids need to be processed in order to remove the hydrocarbons therefrom. The drill cuttings can then be disposed of without harm to the surrounding environment or, for example, they can be used as aggregate for building roads or in other construction projects.

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: 5,914,027; 5,724,751; and 6,165,349 - all these patents incorporated fully herein for all purposes .

In accordance with the present invention, there is provided an apparatus for facilitating separation of hydrocarbons from hydrocarbon laden drill cuttings , the apparatus comprising a thermal treatment apparatus and a feeder apparatus, the thermal treatment apparatus comprising a reactor and the feeder apparatus comprising a metering screw for receiving and feeding drill cuttings material into the reactor, the apparatus further comprising a control system for controlling the metering screw. Preferably, the metering screw feeds directly into the reactor. Preferably, the control system ensures that the metering screw is maintained full or nearly full of material. Preferably, this can be achieved by having a container from which the metering screw draws the hydrocarbon laden drill cuttings and ensuring the container always has a supply of hydrocarbon laden drill cuttings. Advantageously, the control system controls the mass flow rate of hydrocarbon laden drill cuttings into the reactor by adjusting the speed of the metering screw apparatus . Preferably, the reactor has a material inlet and the metering screw passes therethrough, an airlock maintained between the metering screw and the material inlet. Advantageously, the hydrocarbon laden drill cuttings in the screw feeder maintains the airlock. Preferably, the apparatus further comprises at least one temperature measuring device, the control system providing for control of temperature in the reactor by controlling the mass flow rate of material into the thermal reactor by controlling the metering screw that feeds material into the thermal reactor .

Preferably, the thermal treatment apparatus has an engine rotating friction elements within the reactor and performance of the engine is optimized by controlling the metering screw that feeds material into the reactor vessel, for example, based on sensed speed in rpm's of the engine.

Advantageously, the feeder apparatus further comprises a container, the metering screw arranged therein or therebelow. Preferably, the container can store between three and eighteen cubic metres of hydrocarbon laden drill cuttings. Advantageously, the container has an open top. Preferably, the container has a lid, which is open and the interior of the container is maintained at substantially atmospheric pressure, although may be exposed to a slight increase in pressure due to the inlet from a positive pressure pneumatic conveying system introducing hydrocarbon laden drill cuttings into the container. Advantageously, the container has at least two sides which converge towards the metering screw. Preferably, the container comprises a slider mechanism for moving hydrocarbon laden solids to the metering screw. [Preferably, the metering screw is driven by a hydraulic double acting piston and cylinder to draw the frame over an interior surface of the container to move the hydrocarbon laden drill cuttings to the metering screw. Advantageously, the container has a flat, substantially bottom section, the slider frame apparatus sliding hydrocarbon laden drill cuttings on the flat bottom. The bottom section may be planar and may be horizontal. Advantageously, the apparatus further comprises at least one load cell apparatus for weighing the container to give an indication of how much hydrocarbon laden drill cuttings there is in the container. Preferably, the load cell is arranged beneath the container to provide information to indicate an amount of material in the container.

Advantageously, the reactor has a rotor therein, the apparatus further comprising a speed measuring apparatus to measure the rotational speed of the rotor and sends an indication of the speed to the control system. Preferably, if the speed of the rotor slows down, the control system slows down the metering screw to reduce the amount of hydrocarbon laden drill cuttings entering the reactor .

Preferably, the apparatus further comprises a drilling mud processing apparatus which comprises a shale shaker, centrifuge, vortex dryer, hydrocyclone or other solids control equipment.

Advantageously, the apparatus further comprises a second feeder apparatus feeding the reactor. Preferably, the apparatus further comprises a third feeder apparatus feeding the reactor .

Preferably, the metering screw is inclined upwardly towards the reactor. Most preferably, the screw feeder is inclined at an angle of between three and ten degrees and preferably about four degrees from horizontal .

Preferably, the apparatus further comprises a load cell arranged to measure the weight of the reactor to provide information to the control system to control the discharge rate of drill cuttings from the reactor.

The present invention also provides a method for facilitating separation of hydrocarbons from hydrocarbon laden drill cuttings using a thermal treatment apparatus and a feeder apparatus comprising a metering screw the method comprising the steps of the metering screw receiving and feeding drill cuttings material into the thermal treatment apparatus , the thermal treatment apparatus comprising a reactor, the method further comprising the step of a control system controlling the metering screw. Preferably, the reactor has a rotor therein, the apparatus further comprising a speed measuring apparatus to measure the rotational speed of the rotor and sends an indication of the speed to the control system. Preferably, if the speed of the rotor slows down, the control system slows down the metering screw to reduce the amount of hydrocarbon laden drill cuttings entering the reactor. Advantageously, the apparatus comprises a torque measuring device to measure the torque on the rotor and sends an indication of the torque to the control system. Preferably, if the torque of the rotor increases above a predetermined threshold, the control system slows down the metering screw to reduce the amount of hydrocarbon laden drill cuttings entering the reactor.

Advantageously, the method further comprises the step of measuring the weight of the reactor including the hydrocarbon laden drill cuttings therein and providing the measurement to the control system to control the discharge rate of drill cuttings from the reactor.

Preferably, the control system controls the amount of material in the reactor. Advantageously, the reactor comprises a rotating drum, amount of material is controlled by monitoring the speed and/or torque of rotation of the rotating drum and controlling the speed of the screw feeder in response thereto. Preferably, the control system controls the amount to maintain an airlock at the discharge from the thermal reactor. Advantageously, the control system maintains a desired temperature in the thermal reactor by adjusting the speed of the screw feeder.

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. For a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings , in which :

Figure IA is a schematic view of an system in accordance with the present invention;

Figure IB is a top view of the system shown in Figure IA;

Figure 1C is a partial side view of part of the system shown in Figure IA; Figure ID is a view in cross-section of a feeder system of the system shown in Figure IA;

Figure IE is a view in cross-section of a feeder system useful in a system like the system shown in Figure IA; Figure IF is a view in cross-section of a container of a feeder system in accordance with the present invention ;

Figure 2A is a side view partly in cross-section of a feeder system in accordance with the present invention; Figure 2B is an end view of the feeder system shown in Figure 2A;

Figure 2C is a top view of the feeder system shown in Figure 2A;

Figure 2D is a top view of part of the feeder system shown in Figure 2A;

Figure 2E is an end view of a slide of the feeder system shown in Figure 2A;

Figure 3 is a top view of a system in accordance with the present invention; Figure 4 is a schematic view of a system in accordance with the present invention; and

Figure 5 is a schematic view of a system in accordance with the present invention. Figures IA to ID illustrate a system 10 in accordance with the present invention which has a thermal reactor section 12 and a feeder system 40 in accordance with 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. The reactor vessel may be of the type disclosed in UK Patent Application Publication No. 2,337,265.

Figures 1C and ID illustrate the feeder system 40 which has a base 42 with sides 44, 44a, and 44b, and a bottom 45 within which is mounted a container 46 for holding drill cuttings material to be fed to the vessel 14. The bottom 45 may be a skid and the sides 44, 44a, 44b may be structural beams making up a frame. 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 Figure ID, 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 inclined bottom 48 may be at an incline of between one and ten degrees , preferably between three and five degrees and most preferably about four degrees from horizontal. The system 60 inclined to correspond to the incline of the bottom 48. Material falls into a trough 3 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; for example as shown in Figure IF, walls 46w of a container 46a are inclined above a trough 47a.

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 (for example, 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 (for example 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 (for example, 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 (for example 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 Figure ID, a pump 70a may be located within the container 46 (in one aspect, in the material M) . As shown in Figure IE, a conveyor apparatus for conveying material to a vessel like the vessel 14 can have a constant pitch screw 62s; or, as shown in Figure ID, the screw 62 of the system 60 has areas of different pitch, for example areas 62a, 62b, (with the tightest pitch at the end near the motor 52) and 62c 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 (for example in one aspect, a minimum of about three cubic meters) so that an airlock is maintained at the inlet 13. By insuring, using the control system CS as described below, that a sufficient amount of material is within the vessel 14, an airlock is maintained at the discharge outlet 15 of the system 12.

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 Figure 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 50mm and 1000mm and, in one particular aspect, is 500mm. Optionally, or in addition to the load sensor (s) 72, a level sensor and 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 with an integral or separate display and interface for the control system CS. Personnel P can, optionally, remove free liquid from the top of material in the container 46 (for example from the top thereof) by manually placing an end 75a of a pipe 75 within a conduit 77 connected to the container 46 to pump free liquid (for example 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.

The control system CS controls the various operational parts and apparatuses of the system 10 as shown schematically in Figures IA, IB, and ID. In particular aspects, the control system CS receives information from the load cell(s) 72, and from sensors 2 on the engine 17 (for example torque and/or speed in rpm's) and from sensor (s) 52a on the motor 52 (for example motor speed in rpm'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 a 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 52a (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; for example, 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 00 at a sufficient rate that the temperature within the vessel 14 is maintained at a sufficiently high level (without exceeding a pre-set maximum) to effectively heat liquid phase (s) in the drill cuttings material to vaporize the liquid phase (s) . 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 (for example, 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, the temperature within the vessel 14 is maintained by the control system between 250 and 400 degrees Centigrade .

It is also desirable for efficient operation that the engine 17 operates at an optimal loading, for example at 95% of its rated capacity. If the control system CS learns, via a speed sensor 2 on the engine 17 that the RPM' 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' 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 .

Figure IE shows a system 10a, 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 55 (or other processing equipment) whose drill cuttings material output (for example 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; for example, but not limited to: a system in accordance with the present invention (for example, but not limited to a system as in Figures IA, 2A, or 3) ; a storage system for drill cuttings material; a skip system; a cuttings containment and transfer system (for example, but not limited to, a known system as disclosed in U.S. Patent 7,195,084, co-owned with the present invention) ; or a transfer/transport system, for example, but not limited to, the BRANDT FREE FLOW (TRADEMARK) systems. Figure 2A shows a system 10b like the system 10 described above and like numerals indicate like parts .

The system 10b 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 a 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. Patent 7,195,084.

The slider frame 82 has a central beam 86, and, optionally, bevelled end edges 88. The slide 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.

Figure 3 illustrates a system 10c, like the system 10, and like numerals indicate like parts The reactor section 12c has multiple material inlets 13c into which material is introducible into a vessel 14c. One feeder system may be used at one inlet 13c or multiple feeder systems 40c may be used (three shown in Figure 3) . Figure 4 illustrates improvements to systems of U.S.

Patent 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 in accordance with the present invention) which feeds material into a reactor chamber or vessel 201 with a rotor 202 including friction elements 203, such as flails. 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. Patent 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. Patent 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 (for example, 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 air transportation system may be a positive pressure system moving slugs of solids slowly along the pipe or may use high speed air to transport the solids in suspension. Alternatively, a vacuum system may be used. 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. 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. Patent 5,914,027. The items downstream of the vessel 201 may be used with any system in accordance with the present invention.

Figure 5 illustrates that the present invention provides improvements to the systems and methods of U.S. Patent 5,724,751 (fully incorporated herein for all purposes) and shows a system 300 in accordance with 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 by a feeder system 320 (any feeder system disclosed herein in accordance with 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. Patent 5,724,751. The items downstream of the process chamber of the system 300 may be used with any system in accordance with 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 in accordance with 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 (for example, based on sensed speed in rpm'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 (for example, based on sensed speed in rpm'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.