Patent Publication Number: US-2022234009-A1

Title: Chemical injection and mixing device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present disclosure relates to mixing different substances by automatically combining and controlling the substances when one of their flows is at a rate adequate to result in a designated degree of dispersion, and not combining the substances when both flows are less than the rate. 
     2. Description of Prior Art 
     Fluids handling systems generally include vessels, motive devices (such as pumps and compressors), and lengths of pipe for carrying the fluids. Chemicals are sometimes injected into one or more points in the fluids handling systems, which is commonly known as chemical injection. Some reasons for chemical injection are to condition a fluid within the handling system, or remove or neutralize undesirable components in the fluid. One removal technique involves injecting a demulsifier to break an emulsion inside the fluid and facilitate removal of water from crude oil at a gas oil separation plant. The injected chemical is sometimes used to treat the pipe and includes one or more of a scale inhibitor, a corrosion inhibitor, and biocide. These fluid handling systems are sometimes found in gas oil separation plants, crude oil production platforms, crude oil transmission pipelines, chemical and/or petrochemical processing facilities, oil refineries, and well sites for oil production. Uniform and maximum mixing of the chemical into the process fluid generally increases the effectiveness of the injected chemical and reduces operating cost costs. 
     For many injection applications an injection quill is used to inject the chemical into the process stream, but which does not guarantee that adequate mixing occurs so that the injected chemical is effective. In some instances inadequate mixing of an injection chemical into a flow of fluid, such as crude, results in not meeting the product specifications, equipment failure, operation interruption, high chemical consumption, and consequently high operating cost equipment corrosion. 
     SUMMARY OF THE INVENTION 
     Disclosed herein is an example of a method of mixing a primary fluid with an injection chemical that includes directing the primary fluid and the injection chemical to a mixer, flowing the primary fluid and the injection chemical through the mixer to create a combined fluid in the mixer when a velocity of the combined fluid is at least a threshold magnitude so that the combined fluid forms a mixed fluid with a designated heterogeneity, and blocking flow through the mixer when the velocity of the combined fluid is less than the threshold magnitude. In an example, the primary fluid is directed to an entrance of a passage that extends through the mixer and the injection chemical is directed in the mixer where sidewalls of the passage diverge away from one another. Alternatively, the injection chemical is directed in the mixer where sidewalls of the passage converge towards one another. An example of blocking flow through the mixer involves using a valve inside the mixer that is responsive to a velocity of the combined flow. In this example, blocking flow through the mixer the valve is selectively actuated into a configuration so that a portion of the valve contacts sidewalls of a passage inside the mixer and at a location where ports intersect the passage. In an alternative, flowing the primary fluid and the injection chemical through the mixer includes spacing the portion of the valve away from the sidewalls of the passage so that the injection chemical flows through the ports into the passage and the combined fluid flows along a path between the portion of the valve and the sidewalls. Alternatives of the primary fluid are a fluid such as water, oil, a process fluid, and combinations, and for the injection chemical are a substance such as a demulsifier, a scale inhibitor, a corrosion inhibitor, a biocide, and combinations. In an example, inside the mixer a flow path of the combined fluid transitions to a greater cross sectional area to increase heterogeneity of the mixed fluid. The mixer is optionally equipped with multiple passages that each have an end in communication with the primary fluid and an opposite end in communication with the mixed fluid. 
     Also disclosed herein is a mixer that is made up of a body, a passage formed through the body, a port in a sidewall of the passage that is in communication with an injection chemical, the passage has an end in communication with a primary fluid, the primary fluid being selectively combined with the injection chemical to create a combined fluid when a velocity of the combined fluid is at least at a threshold magnitude so that the combined fluid becomes a mixed fluid having a designated heterogeneity. The mixer of this embodiment also includes a valve in the passage that is selectively moveable to a blocking configuration when the velocity is below the threshold level and defines a barrier to flow of the combined fluid through the passage, and when the velocity is at least at the threshold magnitude the valve is moveable to a flowing configuration and that permits a flow of the combined fluid through the passage. The valve is optionally fixed within the passage and comprises a base, a spring, and a disk. In an alternative, the valve includes a valve disk having a lateral surface that extends along a path that is oblique to an axis of the passage, and wherein sidewalls of the passage are oblique to the axis. In an embodiment, the disk is biased from the base by the spring and into the blocking configuration when the velocity is below the threshold level. The spring is alternatively compressed when a spring force of the spring is exceeded by a force exerted onto the disk from the flow of the combined fluid when the velocity is at least at the threshold magnitude. In an example, when the spring is compressed the disk is moved adjacent to the base, and wherein an area of a rearward surface of the disk exceeds an area of a front surface of the base, so that when the disk is a discontinuity is formed along an interface between the disk and base that increases mixing of the primary fluid and injected chemical. In an embodiment, sidewalls of the passage converge towards one another along a converging portion of the passage and diverge away from one another along a diverging portion of the passage, and wherein a throat is defined in the passage between the converging and diverging portions. The port is optionally located upstream or downstream of the throat. In an example, a plurality of ports are disposed around a circumference of the passage. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic example of a fluids handling circuit having a mixer. 
         FIG. 2  is a side sectional view of an example of the mixer of  FIG. 1  in a non-flowing state. 
         FIG. 3  is a side sectional view of an example of the mixer of  FIG. 2  in a flowing state. 
         FIG. 4  is a side sectional view of an alternate example of the mixer of  FIG. 1  in a non-flowing state. 
         FIG. 5  is a side sectional view of an example of the mixer of  FIG. 4  in a flowing state. 
         FIG. 6  is a side sectional view of an alternate example of the mixer of  FIG. 1  in a non-flowing state. 
         FIG. 7  is a side sectional view of an example of the mixer of  FIG. 6  in a flowing state. 
         FIG. 8  is a side sectional view of an alternate example of the mixer of  FIG. 1  in a non-flowing state. 
         FIG. 9  is a side sectional view of an example of the mixer of  FIG. 8  in a flowing state. 
     
    
    
     While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF INVENTION 
     The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/−5% of a cited magnitude. In an embodiment, the term “substantially” includes +/−5% of a cited magnitude, comparison, or description. In an embodiment, usage of the term “generally” includes +/−10% of a cited magnitude. 
     It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. 
     Shown schematically in  FIG. 1  is an example of a fluids handling circuit  8  that includes a mixer  10  shown in communication with a fluid source  12  via line  14 , and in communication with an injection chemical supply  16  via line  18 . A discharge or exit of mixer  10  is in communication with a mixed fluid destination  20  via line  22 . In an example, the fluid handling circuit  8  is part of a larger installation in which fluids (or substances in other states) are handled or processed, non-limiting examples include a refinery, a chemical processing plant, a water purification system, an oil field production system, and the like. Examples of the fluid source  12  include water, oil, a process fluid, and combinations. Examples of the injection chemical supplies  16  include a system that supplies a demulsifier, a scale inhibitor, a corrosion inhibitor, a biocide, and combinations. In a non-limiting example, mixer  10 , a fluid from fluids source  12  and an injection chemical from an injection chemical supply  16  are combined and then mixed so that the fluid and the injection chemical are dispersed within one another to a degree of heterogeneity that is at least at a designated heterogeneity. An example of a designated heterogeneity is that when examining or analyzing a portion of the mixed fluid, a dispersion of the fluid and injection chemical within that sample are substantially uniform, and so that the portion is substantially homogeneous. In this example, the quantity or size of the sample is optionally variable, so that an analysis of different amounts or volumes of the combination of the fluid and injection chemical yield a different degree of heterogeneity. In a non-limiting example, an analysis of a smaller quantity or sample of mixed fluid yields a lower degree of heterogeneity than an analysis of a larger amount quantity of the same mixed fluid. 
     Shown in  FIG. 2  is a side sectional view of an embodiment of mixer  10  between line  14  and line  22  and coupled to lines  14 ,  22  with flanged connections. Mixer  10  of  FIG. 2  includes an outer housing  24  shown as a generally tubular member. Inside housing  24  is a generally solid body  26  intersected by a passage  28  shown extending along an axis A X  of mixer  10 . In the example shown, passage  28  provides fluid commination between line  14  and line  22 . Sidewalls  30  of passage  28  are profiled and shown substantially paralleled with axis A X  along a first Section  32   1  of passage  28 . Along a second section  32   2  sidewalls  30  converge towards one another and downstream of second section  32   2  is a third section  32   3  in which the sidewalls  30  diverge away from one another. A throat  33  is defined along an interface of the second and third sections  32   2 ,  32   3 , the cross sectional area within passage  28  is at a minimum value at throat  33 . A fourth section  324  of passage  28  extends between third section  32   3  and exit of passage  28 . For purposes of illustration, the first section  32   1  has a length shown as L 1 , the second section  32   2  has a length shown as L 2 , the third section  32   3  length L 3  and the forth section  324  has a length L 4 . In this example L 2  is greater than L 3  and L 4  is greater than L 1 , additional embodiments exist in which the lengths L 1-4  are not limited to the illustrations shown and each have magnitudes different from those shown. Further shown is that the diameter D of passage  28  is substantially constant in first section  32   1  and also in fourth section  324  that varies along the axis A X  within the second and third sections  32   2 ,  32   3 . 
     The mixer  10  of  FIG. 2  includes a valve assembly  34  shown within second and third sections  32   2 ,  32   3  of passage  28 . Included with valve assembly  34  is a valve base  36  shown having a frusto-conical shape with a back surface  38  that is substantially perpendicular with axis A X  and on a side of valve base  38  proximate line  22 . A side surface  40  of valve base  36  is on its outer radial portion and which tapers radially inward with distance from its front surface  42  towards its back surface  38 . Front surface  42  of valve base  36  is on an end of valve base  36  opposite from back surface  38  and is intersected by an opening  44  that is formed within the valve base  36  and also has a frusto-conical configuration. Shown radially disposed between opening  44  and the side surface  40  are walls  46 , which similar to side surface  40  are oblique to axis A X . A spring  48  which is shown as coil spring, has an end inserted into opening  44 . In the configuration of  FIG. 2  spring  48  is in an uncompressed state. Elongated struts  50  project obliquely from side surface  40  and attach to the sidewall  30 , and that provide an example manner of securing valve base  36  within passage  28 . 
     Still referring to  FIG. 2 , also included with the valve assembly  30  is a valve disk  52  shown coupled to an end of spring  48  opposite from valve base  36 . Valve disk  52  includes a forward surface  54  on a side facing away from valve base  36 , and a lateral surface  56  that extends obliquely away from forward surface  54  and towards valve disk  36 . In the example of  FIG. 2 , the contour of the lateral surface  56  is substantially the same as the contour of the sidewall  30  in the third section  32   3  of passage  28 . In this example, the sidewalls  30  in this section  32   3  and the lateral surface  56  are each oriented oblique to axis A X . A rearward surface  58  of the valve disk  52  is shown spaced away from and facing the valve base  36  and having an opening  60  formed through the rearward surface  58 . A chamber  62  is formed within the valve disk  52 , an end of spring  48  opposite from valve disk  36  projects through opening  60  and into the chamber  62 . Valve assembly  34  of  FIG. 2  is shown in a blocking configuration, and which is a barrier to a flow of fluid F from line  14  through passage  28 . Also in the blocking configuration valve disk  52  is adjacent ports  64  show intersecting side wall  30 . Leads  66  are shown extending from ports  64  through body  26  into a plenum  68 , which in the example shown is formed in body  26  and circumscribes at least a portion of passage  28 . Line  18 , plenum  68 , lead  66  and port  64  provide a communication path between injection chemical supply  16  and passage  28 , and for the introduction of injection chemical  70  from injection chemical supply  16  into passage  28  for being combined with fluid F. Embodiments exist in which fluid F is one or more of a primary fluid, a dispersed fluid, a solvent, and a solute and injection chemical  70  is respectively one or more of a dispersed fluid, a primary fluid, a solute, and a solvent. In addition to preventing flow of additional fluid F into passage  28 , the valve assembly  34  when in the blocking configuration provides a barrier to flow of injection chemical  70  into passage  28 . 
     In one embodiment of  FIG. 2 , the valve assembly  34  automatically is configured into the blocking configuration at a time when the flow of the fluid F or the primary fluid is such that when combined with the injection chemical  70  the resulting combination undergoes an amount of mixing that is below a designated amount of heterogeneity. Not to be bound by theory, but heterogeneity of the combination of the injection chemical and fluid is dependent at least in part on the velocity of the fluid F being directed into passage  28 . At lesser flowrates of the fluid F and/or injection chemical  70 , which necessarily result in a lower velocity of fluid F and/or injection chemical  70  flowing inside mixer  10  so that the resulting perturbations generated in the combined flow due to kinematic affects are insufficient to produce the level of mixing required to achieve the designated level of heterogeneity. It is believed it is within the capabilities of one skilled to determine a threshold of velocity of the fluid F and/or injection chemical  70  within the mixer  10  required to achieve the designated level of heterogeneity. 
     In a non-limiting example of use, valve assembly  34  automatically reconfigures from the blocking configuration of  FIG. 2  into a flowing configuration as shown in the side sectional view of  FIG. 3 . In this example of a flowing configuration of the valve assembly  34 , the valve disk  52  has been biased axially within passage  28  and moved adjacent valve base  38  so that a combined flow CF of the fluid F and injection chemical  70  flows in an annular space  71  between the sidewalls  30  and the lateral surface  56  of valve disk  52 . In the example of  FIG. 3 , the velocity and or pressure of the fluid F being introduced into passage  28  at a level so that the conditions of the combined flow CF result into a mixed flow MF (schematically illustrated within line  22  and downstream of passage  28 ), where the mixed flow MF has at least the designated degree of heterogeneity. Characteristics of the combined flow CF for producing the sufficiently mixed (e.g. the designated level of heterogeneity) include velocity, pressure, and resulting Reynolds number (Re) of the combined flow. Further shown in  FIG. 3  is that the diameter of the valve disk  52  along its rearward surface  58  is greater than the diameter of the front surface  42  of the valve base  36 . The difference in diameter of these surfaces  56 ,  42  results in a discontinuity  72  with a downstream facing ledge at the outer periphery of the rearward surface  58 . In the example shown, eddy currents  74  are generated downstream of the discontinuity  72  and that redirect a portion of the combined flow CF radially inward. Redirecting the direction of the combined flow CF increases interaction between the fluid F and injection chemical  70  to further promote mixing between the fluid F and injection chemical  70 , and which increases the degree of heterogeneity in the combined fluid CF and to ensure the mixed fluid MF achieves the designated degree of heterogeneity. 
     Further illustrated in  FIG. 3  is an example of a packet  75  of the injection chemical  70  dispersed within the fluid F. Embodiments exist in which the packet  75  has a diameter ranging from a micron or smaller scale to a millimeter or more. The diameter of the packet  75  is optionally adjusted by varying the spring constant of spring  48  and to alter perturbations in the flow of combined fluid CF. Yet further optionally, different dimensions of packet  75  are obtained by altering the shape and/or dimensions of valve disk  52 . In the example of  FIG. 3 , the mixed fluid MF is shown flowing into line  22  and towards its mixed fluid destination  20  and where the advantages of treating the fluid F with the injection chemical  70  to create the mixed fluid F are realized; such by reducing scale, reducing corrosion, emulsifying constituents within the fluid F and preventing emulsions flowing within a line, as well as other benefits that are realized with that injection chemical. 
     In  FIGS. 4 and 5  in side sectional views are an alternate example of a mixer  10 A with multiple passages  28 A 1-4  formed at spaced apart locations within a housing  24 A and through a body  26 A of mixer  10 A. In each of the passages  28 A 1-4  are valve assemblies  34 A 1-4  similar in construction and operation to the valve assembly  34  of  FIGS. 2 and 3 . Also in the embodiment of  FIGS. 4 and 5  are plenums  68 A 1-4  circumscribing each of the passages  28 A 1-4 . Between adjacent passages  28 A 1-4  the plenums  68 A 1-4  are separated by boundaries  76 A 1-3 . The boundaries  76 A 1-3  are not barriers between different plenums  68 A 1-4  but illustrate that injection chemical  70 A is shared between these adjacent plenum  68 A 1-4 . In the example of  FIG. 5  fluid F is shown entering the passages  28 A 1-4  and having a designated velocity and/or pressure to cause springs  48 A 1-4  within each of the valve assembly  34 A 1-4  to automatically change into flowing configurations and allow mixing of the injected chemical  70  with the fluid F and produce a mixed fluid MF shown entering line  22 A. Examples exist where springs  48 A 1-4  have different spring constants so that some open at pressures or velocities of fluid F while others remain closed so that fluid not flowing to each of the passages  28 A 1-4  at each variations of conditions of the fluid F. 
     Another alternate example of mixer  10 B is shown in  FIGS. 6 and 7 . As shown, mixer  10 B is equipped with a single passage  28 B and made up of sections  32 B 1-4  with configurations similar to the sections  32   1-4  of  FIGS. 2 and 3 . Also similar is the valve assembly  34 B and which has shown in a blocking configuration and that operates as a barrier to flow through passage  28 B. In the example of  FIGS. 6 and 7  sections  32 B 1-4  have lengths LB 1-4  respectively. Ports  64 B are provided for communicating injection chemicals  70 B into the passage  28 B, in example shown ports  64 B project through sidewalls  30 B and in the second section  32 B 2  to an upstream of throat  33 B. The blocking configuration of the valve assembly  34 B blocks fluid flow through passage  28 B and prohibits injection of fluid F into passage  28 B as well as the injection chemical  70  through the ports  64 B. In an alternative, a check valve or valves (not shown) are provided within leads  66 B or alternatively within line  18 B. The check valves prevent backflow of fluid F into the plenum  68 B or line  18 B. Similar to the example of  FIGS. 2 and 3 , the fluid F is at a pressure and or velocity that is below the value or threshold for sufficiently mixing the injection chemical  70  and fluid F for achieving a designated level of heterogeneity in a mixed fluid or combined fluid downstream of mixture  10 B. Referring now to  FIG. 7 , the valve assembly  34 B has automatically (due to compression of the spring  48 B) reconfigured into a flowing configuration and that allows the flow of the injection chemical  70 B into the passage  28 B via port  64 B; and the increased velocity across the annular space  71 B produces the mixed flow MF due to the valve assembly  34 B opening when the flow of the fluid F is sufficient to achieve the designated level of heterogeneity. In the example of  FIG. 7 , it is noted that the dimensions of the rearward surface  58 B and front surface  42 B are generally similar and so that a continuous surface  78 B is formed along the interface between the lateral surface  56 B and side surface  40 B. Unlike the configuration of  FIGS. 2 and 3  that include a discontinuity  72 , in the configuration of  FIGS. 6 and 7  the valve base  38 B and the frusto-conical shape increase the cross sectional area inside the passage  28 B downstream of the continuous surface  78 B. The increased cross sectional are generates eddy currents  74 B that as described above promote mixing of the combined fluid CF so that a mixed fluid MF is formed having a level of mixing that is at least that of a designated level of heterogeneity. 
     Shown in side sectional view in  FIGS. 8 and 9  is another alternate example of a mixer  10 C having an outer housing  24 C and multiple passages  28 C 1-4  axially through the body  26 C. In this example valve assemblies  24 C 1-4  are provided within the passages  28 C 1-4  and where the valve assemblies  34 C 1-4  are similar to the valve assembly  34 B of  FIGS. 6 and 7 . Additionally, injection chemical  70  is introduced into the passage is  28 C 1-4  at ports  64 C 1-4  that are within the second section  32 C 2  of the respective passages  28 C 1-4 ; and similar to the configuration of  FIGS. 4 and 5 , plenums  68 C 1-4  circumscribe passages  28 C 1-4  and adjacent plenums  68 C 1-4  interface along boundaries  76 C 1-3 , but the injection chemical  70 C 1-3  is flowable across the boundaries  76 C 1-3 . As depicted in  FIG. 9 , the valve assemblies  34 C 1-4  are in a flowing configuration and which provides for a flow of the injection chemical  70  and fluid F through the passages  28 C 1-4  to produce a mixed fluid MF exiting the passages  28 C 1-4  and into the line  22 C downstream of the mixer  10 C. Alternatively, springs  48 C 1-4  within the valve assemblies  34 C 1-4  are changeable between the blocking and flowing configurations at different values of velocity or pressure within the passages  28 C 1-4 . 
     The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.