WO1992013141A1

WO1992013141A1 - Method and apparatus for control of addition of modifying agent for in place treatment

Info

Publication number: WO1992013141A1
Application number: PCT/US1992/000605
Authority: WO
Inventors: Paul J. Pettit; Roberto E. Frulla
Original assignee: Halliburton Nus Environmental Corporation
Priority date: 1991-01-25
Filing date: 1992-01-24
Publication date: 1992-08-06
Also published as: AU1364892A

Abstract

A method and apparatus enable the concentration of a treating fluid (2) applied to a material (5), such as soil, sludge or waste, to be controlled in response to the directions and rates of movement of a blending tool (16) moved in at least one direction through the material (5). In particular, the flow rate of the treating fluid (2) is controlled in response to the sensed direction and/or rate of movement of the blending tool (16), the properties of such subsurface material, and/or the location of the blender (16) in reference to a map of the properties of the site being treated. Properties of the treating fluid and/or of individual modifying agents used in making the treating fluid can also be sensed and used in controlling the flow rate and/or the composition of the treating fluid.

Description

METHOD AND APPARATUS FOR CONTROL OF ADDITION

OF MODD7YING AGENT FOR IN PLACE TREATMENT

This invention relates generally to a method and apparatus for treating a volume of material in situ and more particularly, but not by way of limitation, to a method and apparatus for controlling the flow of modifying agents in response to the direction and/or rate of movement of a blender lowered into subsurface material such as contaminated soil, sludge or waste, the properties of such subsurface material and/or the location of the blender in reference to a map of the properties of the site being treated.

Environmental contaminants in unstable form exist in subsurface material, such as soil, sludge or waste products, at many industrial and commercial sites. In some cases, release of these contamin∑mts into the surrounding environment can be controlled or mitigated by mixing the material with a treating fluid containing one or more modifying agents, which treating fluid solidifies and/or stabilizes the contaminants or provides some other treatment such as chemical or physical treatment (as used herein "treating fluid" encompasses not only liquid and gaseous treating agents, but also solid or dry treating agents; such treating agents can be "flowed" and mixed into the subsurface material-where ground water or an irrigation source of water exists, the water may participate in the stabilization process). The effectiveness of such a process depends not only on the selection of the modifying agent or agents making up the treating fluid, but also on the ability to control the process variables to achieve the addition of a sufficient portion of treating fluid and to mix it with the material to obtain a prescribed concentration throughout the volume of contaminated material. Although contaminated materials can presently be treated, the treatment methodologies of which we are aware cannot control the flow or addition of the treating fluid or its constituents, in such a manner as to achieve a specific concentration of the treating fluid throughout the volume to be treated simultaneously with the in situ advancement of the mixer.

Accordingly, there is the need for an improved method .and apparatus which can conduct solidification and/or stabilization and/or other treatment in a continuous, controlled manner in contaminated material in situ. This improvement should achieve improved control of the flow of treating fluid and of its mixture in situ to obtain a prescribed concentration in the contaminated material.

The present invention overcomes the above-noted and other shortcomings of the prior art by providing a novel and improved method and apparatus for treating a volume of material. The present invention provides prescribed concentrations of treating fluid to the material, while treating the material in three dimensions, without extracting the blender through which the treating fluid is placed in the material. That is, the present invention provides continuous, controlled treatment of material simultaneously with the in situ advancement of the blender, which advancement can be through one or more directions within the volume of material. The present invention has particular application to treating subsurface contaminated soil, sludge or waste; but it is not necessity limited to this use. Another use may be for treating soil to increase its ability to support structures.

The method and apparatus for treating a volume of material in situ comprise steps of and means for moving a blender in one or more directions within the material, sensing the directions of movement of the blender in the material, sensing the rates of movement of the blender in the material, sensing the properties of the material being treated and/or sensing the location of the blender in reference to a map of the properties of the site being treated, and flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed direction of movement, rate of movement, properties, and/or location.

Therefore, from the foregoing, the present invention provides a novel and improved method and apparatus for treating a volume of material in situ to achieve a prescribed addition of treating agent(s) in all parts of the material to be treated. Other and further objects, features and advantages of the invention will be readily apparent to those skilled in the art when the following description of the preferred embodiments is read in conjunction with the accompanying drawing.

The drawing is a schematic and block diagram of a system by which the method and apparatus of the present invention can be implemented.

A system for implementing the apparatus and method of the present invention is depicted in the drawing. A source 2 of one or more modifying agents is connected to a mixer 4 (the mixer 4 may not be needed if the agents are delivered pre-mixed or if only a single agent is used). The modifying agents are conventional, as are the source 2 and the mixer 4. For example, the source 2 can be one or more trucks having storage vessels for transporting the modifying agents to the ground level site where in situ treatment of subsurface material 5 is to occur, and the mixer 4 can be a mechanical homogenizer wherein a homogeneous mixture of treating fluid is made. Examples of conventional modifying agents for treating subsurface soil contaminated by metals and organic materials include cement and fly ash.

The output of the mixer 4 is connected to a conventional pump 6, such as a centrifugal pump. The output of the pump 6 is connected to a control v ve 8, through which the flow from the pump 6 to in situ blender equipment 10 is controlled. The control valve 8 is conventional, such as a hydraulically actuated proportioning valve. The control valve 8 is automatically operated by a digital computer controller 12 such as can be implemented by a Halliburton Services UniPro Controller using a Motorola 6800 series microprocessor. The controller 12 operates the valve 8 to control the addition and portioning of the treating fluid into the subsurface material 5 as applied through the equipment 10. Thus, the pump 6, the valve 8 and the controller 12 are used to flow the treating fluid into the subsurface material 5 through the blender equipment 10.

The "treating fluid" used in this invention is not limited to liquid or gaseous material. Rather, it includes any sort of material that can be flowed and mixed into the subsurface material. Thus the treating fluid of this invention can either include, or be entirely composed of, solid or dry treating agents.

In the preferred embodiment, the in situ blender 10 is implemented by a known type of equipment which includes not only pipe 14 and a blending tool 16 through which the treating fluid is conducted and injected into the subsurface material 5, but also transportable motor device 18 for carrying and moving the pipe 14 and the blending tool 16. The pipe 14 includes the necessary hoses and drilling members for connecting to the conduit containing the valve 8 and for carrying the blending tool 16 to the desired subsurface locations. The blending tool 16 can be implemented with a conventional device such as a hollow auger having nozzle ports through which the treating fluid is ejected. Another example is a propeller or screw type of mixing or blending tool.

With the auger type of blending tool 16, the motor device 18 rotates and lowers the auger into the subsurface material 5 to move the string of pipe and blending tool into the material to be treated. During this procedure, the rotating auger cuts the material into pieces and the treating fluid is ejected out of the auger's ports while the cutting action occurs. Continued movement of the auger blends or mixes the treating fluid into the cut pieces and continues to break up the pieces to produce treated material. These components and this operation of the situ blender can in general be implemented with a Halliburton Environment Technologies' In Situ Blender 6; however, the following feature of the in situ blender 10 is unique to the present invention.

In the in situ blender 10 of the present invention, the motor device 18 is able to move the string of pipe and blending tool not only vertically but also horizontally. These movements can be simultaneous. That is, the motor device 18 is able to move the string in three dimensions while the blending tool 16 and at least part of the pipe 14 are in the subsurface material 5. Such subsurface lateral movement increases the volume of material that can be treated with a single trip into the material. Thus, the motor device 18 of the present invention rotates the blending tool 16 and moves it through at least one direction within the subsurface material. Movement of the blender can be implemented by a crane with hydraulic controls.

Another unique feature of the present invention is the technique by which a desired concentration of treating fluid in the volume of treated subsurface material is obtained. In one embodiment of the present invention, the desired concentration is obtained by controlling the valve 8 in response to the direction of movement of the subsurface blender and/or rate of movement in this direction. The control is provided through the controller 12. The direction and rate information is provided to the controller 12 by motion sensors 20, 22, 24, connected to the motor device 18 to sense its movement of the subsurface blending tool 16 along the three axes illustrated in the drawing. The sensors, 20, 22, 24 are conventional (such as optical encoders), and they are connected to the motor device 18 in a known manner. The outputs of typical motion sensors 20, 22, 24 are electrical signals encoded with the direction and rate information in a manner which can be input into the controller 12.

In response to the signals from the sensors 20, 22, 24, the controller 12 generates and outputs a control sign∑d to the valve 8 to adjust how much treating fluid is passed for injection into the subsurface material 5. Thus, the flow rate of the treating fluid is responsive to the sensed direction of movement and/or rate of movement of the blending tool 16 within the subsurface material. The speed of rotation of the blending tool 16 is sensed by a sensor 25, such as an optical encoder or magnetic pickup device, can also be used in the control of the flow rate of the treating fluid. The sensor 25 is connected in a known manner with the pipe 14 and the controller 12. A monitoring feedback signal is provided by a conventional flow sensor 26, such as a Halliburton Services' turbine flow meter. A specific implementation of the control could employ a PID (proportional, integral and derivative) automatic feedback control loop.

It is also contemplated that the flow rate of the treating fluid can be controlled in response to one or more sensed properties of the treated material (i.e., the treated subsurface material 5 in the illustrated environment). Such sensing can be done with one or more subsurface sensors 28 attached to the blending tool 16. Examples of suitable subsurface sensors are a pH meter and a Halliburton Services radioactive densimeter. This provides one or more electrical signals encoded to identify the sensed property(ies), such as the pH or density of the subsurface material 5. The one or more signals are provided to the controller 12 for use in generating the control signal for the valve 8. Signals from these instruments are to be compared to pre-established property information set into the controller 12. When a deviation is indicated by a sensor, the controller 12 automatically adjusts the quantity, rate or proportion of the treating fluid to accommodate and correct for the deviation. For example, should decreased density of the in situ material be sensed, indicating additional (unexpected) voids, the controller 12 will decrease the amount of the treating fluid added.

It is further contemplated that the flow rate of the treating fluid can be controlled in response to one or more sensed properties of the treating fluid itself. Such sensing can be done with one or more sensors 30 connected to the mixer 4 (or the discharge from the mixer 4) for sensing one or more properties of the mixture defining the treating fluid and/or with one or more sensors 32 connected for sensing one or more properties of the individual modifying agents flowing into the mixer 4. An example of a suitable sensor 30, 32 is a Halliburton Services radioactive densimeter. This provides an electrical signal encoded to identify density of the treating fluid. These signals are provided to the controller 12 for use in generating the control signal to the valve 8. These signals are used in a manner similar to those described in the preceding paragraph. For example, should the densimeter 30 sense that the density of the treating fluid declines (due to low concentration of mixed agent in it), the controller 12 will automatically increase the flow rate of the treating fluid to compensate. Thus, the product of the flow rate and concentration (density) remains constant for a constant rate of treatment.

The means for sensing the properties of the material to be treated, while preferably an integral part of the treating apparatus of this invention, can optionally be separated from the treating apparatus in time and space. A preferred embodiment of this later aspect of the invention is where the sensing means is used separately to create a map of the site to be treated indicating the properties of the materials to be treated, preferably in a three-dimensional array. An acceptable embodiment is to provide means for conducting test borings and samplings at various locations on the site to be treated, and then to provide means for analyzing the samples taken to provide information for a map of the site to be treated. The "map," as used herein, is a description of the properties of the materials of the site to be treated which is sufficient to enable the treating apparatus to regulate the treating for the different horizontal and vertical locations on the site to be treated to accomplish a desired objective. The properties of the materials being treated include, but are not limited to identity and/or concentration of chemical constituents, pH, temperature, fluidity, porosity, hardness, quantity and nature of microorganisms and nutrients for such microorganisms present. In summary, signals provided to the controller 12 for use in generating the control signal to the valve 8 may originate from a variety of sources and detect a variety of parameters. They may arise from motion sensors detecting the rate and or direction of movement. They may arise from sensors detecting one or more properties of the treating fluid and/or the material to be treated. They may arise from a system detecting the position of the blender and correlating that position with a predetermined "map" of the properties of the material to be treated. The selection and/or rate of flow of treating fluid may be responsive to one or more of these sensed parameters.

In addition to or alternatively to controlling the valve 8, and thus the flow rate of the treating fluid, in response to the aforementioned sensed parameters, the plurality of modifying agents can be mixed in response to these parameters. That is, the amounts of the modifying agents flowed into the mixer 4 can be controlled in response to these parameters. One particularly relevant parameter to use is the property or properties of the subsurface material sensed by the sensor(s) 28. Such other control is implemented by the "other input control information" and "other output control signal(s)" shown in the drawing. As another example, torque sensors indicating any additional requirement for power can be used to control speed of advancement and rate of progress of the work based on requirements of the particular blender tool being employed. Such data can be used to determine whether either a different size blender or a different rate of advancement would be desirable for the particular situation.

Also shown in the drawing is a multiple display/recorder unit 34. This can be a conventional device, such as a strip chart recorder or a nonconventional Halliburton Services Compupac computer data acquisition system, which displays or records data.

Utilizing the system illustrated in the drawing, the method of the present invention for treating a volume of subsurface material in situ can be performed. This includes moving the blending tool 16 in at least one direction within the material. For example, the blending tool 16 is lowered into the subsurface material 5 and moved laterally within the subsurface material 5 while the blending tool 16 is within the subsurface materiϊil 5. More particularly, the motor device 18 rotates the tool 16 and moves the rotating tool 16 through at least one direction within the subsurface material 5. Movement of the blending tool 16 in vertical and horizontal directions within the material can occur simultaneously.

The method further comprises sensing the direction of movement of the tool 16 in the subsurface material 5 and/or the rate of movement thereof. As previously mentioned, other parameters such as the position of the blender and one or more properties of the subsurface material, the treating fluid and/or the individual modifying agents can also be sensed.

The method still further comprises flowing the treating fluid into the subsurface material 5 through the tool 16 at a flow rate responsive to the sensed direction and/or rate of movement (and any of the other sensed parameters if desired). This flowing preferably occurs simultaneously with the movement of the blending tool 16 through the materi∑d. In the preferred embodiment, this includes pumping mixed treating fluid into the pipe 14 and the blending tool 16 at a flow rate controlled by the valve 8 as actuated by the digital computer controller 12. This is done in response to the sensed direction and/or rate of movement of the tool 16 within the subsurface material 5 so that the mixed treating fluid is ejected from the ports of the blending tool 16 to obtain a predetermined concentration of the treating fluid in the subsurface material traversed by the blending tool 16.

This controlled pumping obtained via control of the valve 8 can also be responsive to any of the other described parameters which are sensed. Additionally, the mixing of the treating fluid can be controlled in response to one or more of the sensed properties. For example, the flows of multiple modifying agents into the mixer 4 can be controlled through conventional valves in response to sensed properties of the treated subsurface material or other sensed parameters as described above.

In accordance with the foregoing, the process control implemented by the basic preferred embodiment of the present invention operates on the basis of the motion imparted to the components of the blender 10 emplaced in the material (this is to what "movement of the blender" or "blender motion", etc. refers to herein and in the claims). As the blender moves, the digital computer controller controls the addition and portioning of the treating fluid, made of one or more modifying agents, based on the rate at which the blender advances in any direction, cutting into previously uncut material which is treated as the blender advances. On this basis, the portioning of the treating fluid added and mixed into the subsurface material is controlled by the computer controller 12, in accordance with a prescribed value.

As also described, additional control can be achieved in response to sensed properties encountered in new cut material, from which information the computer controller 12 can adjust the portion and/or quality of the treating fluid to conditions pertaining to the new properties encountered. These adjustments can include control of a plurality of modifying agents used to make the treating fluid (it is to be noted that only a single modifying agent may be used in some cases so that then the single modifying agent is also the treating fluid). Additional control can be achieved by using sensors in the feeds of the modifying agents and/or treating fluid to sense their properties, which information can also be used to adjust the feed rates to compensate for variability of properties of the feeds.

Preferred embodiments of the present invention have been described hereinabove; however, such are not to be taken as necessarily limiting the present invention. Examples of variations which are contemplated as encompassed within the present invention include but are not limited to the following. The present invention is applicable to the feeding of modifying agent or treating fluid in hydraulic form or in solid and/or dry powder form. The present invention pertains to the feed of treating fluid through delivery nozzles or other delivery devices which are not necessarily an integral part of a blending tool, which blending tool can be of any suitable type and design. Such blending tools can be rotated at fixed or variable speeds. The blending tools do not necessarily have to rotate in their entirety, but they can comprise moving or rotating parts which cut the material to be treated into pieces and mix and blend the treating fluid into the cut material, which material can be soil, sludge, waste or other material through which the blending tool can be moved. The material to be treated can also include surface material as well as subsurface material. The present invention can also be used with blending tools operated from a drive shaft or from a positioning shaft which does not rotate but is used to position the blender.

While preferred embodiments of the invention have been described for the purpose of this disclosure, changes in the construction and arrangement of parts and in the performance of steps can be made by those skilled in the art, which changes are encompassed within the spirit of this invention as defined by the appended claims.

Claims

CLAIMS:

1. A method of treating a volume of material in situ, comprising: moving a blender in at least two directions within the material; sensing the directions of movement of the blender in the material; and sensing the rates of movement of the blender in the material; and flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed directions and rates of movement.

2. The method as defined in claim 1, wherein: said method further comprises sensing a property of the material; and said flowing a treating fluid is further responsive to the sensed property of the material.

3. The method as defined in claim 2, wherein: said method further comprises sensing a property of the treating fluid; and said flowing a treating fluid is further responsive to the sensed property of the treating fluid.

4. The method as defined in claim 1, wherein: said method further comprises sensing a property of the treating fluid; and said flowing a treating fluid is further responsive to the sensed property of the treating fluid.

5. The method as defined in claim 1, further comprising: sensing a property of the material; and mixing a plurality of modifying agents to make the treating fluid in response to the sensed property of the material.

6. The method as defined in claim 1, wherein said moving a blending includes lowering the blender into the material and moving the blender laterally within the material.

7. The method of treating a volume of subsurface material in situ, comprising: rotating a blending tool having ports through which to eject a treating fluid; moving the rotating blending tool simultaneously through at least two directions within the subsurface material; mixing a plurality of modifying agents to make the treating fluid; sensing the directions and rates of movement of the blending tool within the subsurface material; and pumping the mixed treating fluid into the blending tool at a rate responsive to the sensed directions and rates of movement of the blending tool within the subsurface material so that the mixed treating fluid is ejected from the ports of the blending tool to obtain a predetermined concentration of the treating fluid in the subsurface material traversed by the blending tool.

8. The method as defined in claim 7, wherein: said method further comprises sensing a property of the subsurface material; and said pumping a blended treating fluid is further responsive to the sensed property of the subsurface material.

9. The method as defined in claim 8, wherein: said method further comprises sensing a property of the blended treating fluid; and said pumping a blended treating fluid is further responsive to the sensed property of the treating fluid.

10. The method as defined in claim 9, wherein said mixing a plurality of modifying agents includes controlling the flow of the modifying agents in response to the sensed property of the subsurface material.

11. The method as defined in claim 7, wherein: said method further comprises sensing a property of the blended treating fluid; and said pumping a blended treating fluid is further responsive to the sensed property of the treating fluid.

12. The method as defined in claim 7, wherein: said method further comprises sensing a property of the subsurface material; and said mixing a plurality of modifying agents is responsive to the sensed property of the subsurface material.

13. An apparatus for treating a volume of subsurface material in situ, comprising: means for moving a blender in at least two directions within the subsurface material; means for sensing the directions of movement of the blender in the subsurface material; means for sensing the rates of movement of the blender in the subsurface material; and means for flowing a treating fluid into the subsurface material through the blender at a flow rate responsive to the sensed directions and rates of movement.

14. The apparatus as defined in claim 13, wherein: said apparatus further comprises means for sensing a property of the subsurface material; and said means for flowing a treating fluid is further responsive to the sensed property of the subsurface material.

15. The apparatus as defined in claim 14, wherein: said apparatus further comprises means for sensing a property of the treating fluid; and said means for flowing a treating fluid is further responsive to the sensed property of the treating fluid.

16. The apparatus as defined in claim 13, wherein: said apparatus further comprises means for sensing a property of the treating fluid; and said means for flowing a treating fluid is further responsive to the sensed property of the treating fluid.

17. The apparatus as defined in claim 13, further comprising: means for sensing a property of the subsurface material; and means for mixing a plurality of modifying agents to make the treating fluid in response to the sensed property of the subsurface material.

18. The method as defined in claim 1, wherein: said two directions within the material comprise a vertical direction and a horizontal direction.

19. The method as defined in claim 7, wherein: said two directions within the subsurface material comprise a vertical direction and a horizontal direction.

20. The method as defined in claim 1, wherein: said two directions within the material comprise two vertical directions.

21. The method as defined in claim 7, wherein: said two directions within the subsurface material comprise two vertical directions.

22. The method as defined in claim 1, wherein: said two directions within the material comprise two horizontal directions.

23. The method as defined in claim 7, wherein: said two directions within the subsurface comprise two horizontal directions.

24. The method as defined in claim 1, wherein: said volume of material comprises contaminated soil, sludge or waste; and said treating fluid solidifies, stabilizes and/or chemically treats said contaminated soil, sludge or waste.

25. The method as defined in claim 7, wherein: said volume of material comprises contaminated soil, sludge or waste; and said treating fluid solidifies, stabilizes and/or chemically treats said contaminated soil, sludge or waste.

26. A method of treating a volume of material in situ, comprising: moving a blender within the material in one direction; sensing the direction of movement of the blender in the material; sensing the rate of movement of the blender in the material; and flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed direction and rate of movement.

27. The method as defined in claim 26, wherein: said volume of material comprises contaminated soil, sludge or waste; and said treating fluid solidifies, stabilizes and/or chemically treats said contaminated soil, sludge or waste.

28. The method as defined in claim 26, wherein: said direction of movement of the blender in the material comprises either a horizontal or a vertical direction.

29. A method of treating a volume of material in situ, comprising: moving a blender within the material in one direction; sensing the rate of movement of the blender in the material; and flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed rate of movement.

30. The method as defined in claim 29, wherein: said volume of material comprises contaminated soil, sludge or waste; and said treating fluid solidifies, stabilizes, and/or chemically treats said contaminated soil, sludge or waste.

31. The method as defined in claim 29, wherein: said method further comprises sensing a property of the material; and said flowing a treating fluid is further responsive to the sensed property of the material.

32. A method of treating a volume of material in situ, comprising: moving a blender within the material in one or more directions; sensing the direction of movement of the blender in the material; sensing the rate of movement of the blender in the material; sensing a property of the material; and flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed direction of movement, rate of movement, and/or property of the material.

33. A method of treating a volume of material in situ, comprising: moving a blender in one or more directions within the material; sensing the direction of movement of the blender in the material; and/or sensing the rate of movement of the blender in the material; and/or sensing the properties of the materials to be treated; and/or sensing the location of the blender relative to a map of the properties of the site to be treated; flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed direction, rate of movement, properties, and/or location.

34. A method of treating a volume of material in situ, comprising: providing a map of the properties of the site to be treated; moving a blender in one or more directions within the material; sensing the location of the blender in the material; and flowing a treating fluid into the material through the blender at a flow rate responsive to the sensed location relative to said map.

35. The method as defined in claims 35, wherein: said volume of material comprises contaminated soil, sludge or waste; and said treating fluid solidifies, stabilizes and/or chemically treats said contaminated soil, sludge or waste.

36. The method as defined in claim 33, wherein: said volume of material comprises contaminated soil, sludge or waste; and said treating fluid solidifies, stabilizes and/or chemically treats said contaminated soil, sludge or waste.