Recombination of the working medium used to operate the control valve

Abstract

Recovery units configured to reinject lost or fugitive emissions back into a pipeline are disclosed. These configurations may include, for example, a pressure vessel that may hold a gas (or other fluid) that may be released to the atmosphere through a valve or similar flow control device. A pump may be coupled to the pressure vessel. In use, the pump may draw fluid from the pressure vessel, pressurize it, and inject it back into the pipeline, typically downstream of the valve. The pump may utilize upstream pressure as a power source.

Description

[Technical Field]

[0001] Flow control devices play a major role in many industrial facilities. For example, power plants and industrial processing facilities use different types of flow control devices to manage the flow of materials, typically fluids, throughout vast networks of pipes, tanks, generators, and other equipment. Oil and gas facilities may use pneumatic or electropneumatic control valves to regulate the flow of hydrocarbons, such as natural gas. These facilities may direct line pressure to the control valve as the operating or "working" medium for onboard pneumatic actuators. This feature is advantageous in remote locations, where power, such as electricity, may be scarce or in short supply. However, while convenient, flow control devices often bleed or vent this working medium directly to the atmosphere as part of normal valve operation. Summary of the Invention

[0002] The subject matter of this disclosure relates to improvements to recover most, if not all, of this "lost" working medium. Of particular interest are embodiments that can collect the working medium and reinject it back into the facility's pipeline (or other portion of the facility's system or network). These embodiments can use the pressure differential across the flow control device to increase the pressure of the working medium to a level found downstream of the flow control device. This feature can prevent product loss and reduce greenhouse gas emissions. [Brief explanation of the drawings]

[0003] This specification makes reference to the following drawings: [Figure 1] FIG. 2 is a schematic diagram of a recovery unit. [Figure 2] FIG. 1 is a schematic diagram of an example of a fluid circuit for use in a recovery unit. [Figure 3] FIG. 1 is a schematic diagram of an example of a fluid circuit for use in a recovery unit. [Figure 4]FIG. 1 is a schematic diagram of an example of a fluid circuit for use in a recovery unit. [Figure 5] FIG. 4 is a schematic diagram of an example of the fluid circuit of FIG. 3. [Figure 6] FIG. 1 is a diagram illustrating an example of a flow rate control device.

[0004] These drawings and any descriptions herein represent examples that may disclose or describe the invention. These examples, including the best mode, enable one skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The drawings are not to scale unless otherwise noted in the description. Elements in each example may appear in one or more of the figures or combinations of the figures. The figures may use like reference numerals to indicate identical or corresponding elements. Each method is merely exemplary and may be modified, for example, by reordering, adding, removing, and / or changing individual steps or steps. In this specification, such steps, as well as any parts, components, elements, or functions, may be identified in the singular using the word "a" or "an." However, this should not exclude the plural of such designation unless the specification expressly states or explains such exclusion. Similarly, reference to "one embodiment" or "one implementation" should not be interpreted as excluding the existence of additional embodiments or implementations that also incorporate the recited features. DETAILED DESCRIPTION OF THE INVENTION

[0005] Next, we will discuss features of each example shown in the figures above. These features can improve compliance and profitability for operators. Operators are eager to reduce product losses as much as possible. They are also under considerable pressure to reduce carbon or hydrocarbon (or greenhouse gas) emissions to meet local regulations or generally be good stewards of the environment. As discussed herein, each example illustrates fluid circuits that can capture fluids, such as natural gas, from various locations along an operator's pipeline network. These circuits can prevent this natural gas from the atmosphere and, in fact, reinject the natural gas back into the pipeline network as part of normal processing operations. Other embodiments are within the scope of this disclosure.

[0006] 1 shows an example of a collection unit 100. This example is typically found in a distribution network 102 designed to transport material 104 throughout a network of conduits 106. The network 102 may include a flow control device 108 having a valve body 110 connected in series with the conduits 106. The device may also have an actuator 112. A valve stem 114 may extend from the actuator 112 to position a closure member 116 adjacent to a seat 118. In one implementation, the collection unit 100 may have fluid circuits 120 coupled to the conduits 106 on either side of the flow control device 108.

[0007] Generally, capture units 100 may be configured to recapture gases that are often lost to the atmosphere. These configurations may incorporate components that can operate on this "lost" gas. These components may capture lost gases, such as fugitive emissions or gases released during normal process operation. The components may also increase the pressure of the captured gas, allowing operators to reinject the pressurized gas back into their process. These features are beneficial because they allow operators to prevent direct greenhouse gas emissions while also realizing revenue from the "reinjected" gas.

[0008] Distribution systems 102 may be configured to deliver or move resources. These configurations may embody vast infrastructures. Materials 104 may include gases, liquids, solids, or even mixtures. Conduits 106 may include pipes or pipelines that often connect to pumps, boilers, etc. Pipes may also connect to tanks or reservoirs. In many facilities, this equipment forms a complex network.

[0009] Flow control devices 108 can be configured to regulate the flow of material 104 through conduits 106 in this complex network. These configurations can include control valves and similar devices. The valve body 110 in such devices is often made of cast or machined metal. This structure can form flanges at openings I and O. Adjacent pipes 106 can be connected to these flanges. The actuator 112 can include a pneumatic cylinder that requires compressed or pressurized gas and cooperates with a piston, spring (or multiple springs), or flexible diaphragm to generate the load. The valve stem 114 can form an elongated cylinder or rod that directs this load to a closure member 116, which is often a cylindrical block or plug. The load can govern the position of the plug to prevent flow through the opening in the seat 118.

[0010] The fluid circuit 120 may be configured to couple with pressures upstream and downstream of the flow control device 108. These configurations may include devices that can hold or retain the material 104. Other devices may pressurize the material 104. Together, these devices can form a system that can flow the material 104 back into the distribution system 102.

[0011] FIG. 2 shows a schematic diagram of one example of a fluid circuit 120. This example includes components, such as a recovery circuit 122 having an interface 124 and a line 126. The components 124, 126 may direct gas from within or around the flow controller 108 to a pressure vessel 128, such as a tank or reservoir. In one implementation, the interface 124 may form an envelope around all or a portion of the flow controller 108. The envelope may capture "escaping" gas from the device, for example, from packing, exhaust ports, or other areas that may be vented to the atmosphere. This escaping gas may pass through the line 126 and enter the pressure vessel 128. A pump 130 may be coupled to an inlet line 132 that connects the pressure vessel 128 to the conduit 106 downstream of the flow controller 108. The pump 130 may require power, such as an electrical or pneumatic source. A control circuit 134 may be coupled to the pump 130. The control circuit 134 can include a power source 136, such as a battery or mains power available on-site. The power source 136 can energize the controller 138. In one implementation, the controller 138 can receive feedback defining operating parameters of the fluid circuit 120. These operating parameters can include, for example, a "tank" pressure corresponding to the pressure of the fluid in the pressure vessel 128. The controller 138 can compare the pressure to a threshold. A pressure equal to or greater than the threshold can cause the controller 138 to generate a signal P that activates the pump 130. The signal P may represent a current or a voltage. These signals can regulate the state of the pump 130. In its "on" or operating state, the pump 130 can draw escaping gas from the pressure vessel 128. The pump 130 can increase the pressure of the escaping gas, allowing it to flow back through the inlet line 132 into the conduit 106, for example, at a pressure equal to or similar to that found downstream of the flow control device 108. The controller 138 may, for example, place the pump 130 in its "off" or non-operating state in response to the tank pressure being below a threshold value, which allows escaping gas to fill the pressure vessel 128.

[0012] FIG. 3 shows a schematic diagram of another example of fluid circuit 120. Pump 130 can embody a pneumatic pump, requiring pneumatic logic 140 with flow components such as a check valve 142, a pressure regulator 144, or a valve 146. Components 144, 146 can be connected to a source line 148 that carries pressure from a conduit 106 that connects upstream of flow controller 108. The pressure can power or act to operate air pump 130. In one implementation, controller 138 can manipulate signal P in response to a relationship between tank pressure and a threshold value. This feature can change the state of valve 146 between its “open” state and its “closed” state. The open state can allow pressure to energize air pump 130, for example, to draw escaping gas from pressure vessel 128, pressurize it, and inject it back into conduit 106 through inlet line 132 at the same or similar pressure as found downstream of flow controller 108. The closed state may prevent pressure from the air pump 130. This feature may turn the pump off to allow escaping gas to fill the pressure vessel 128.

[0013] FIG. 4 shows a schematic diagram of another example of fluid circuit 120. Pump 130 can embody an ejector or similar vacuum pump. Ejector 130 can include a high-pressure inlet (HP) coupled to valve 146. A low-pressure inlet (LP) can be coupled to pressure vessel 128. In use, high-pressure flow through ejector 130 can create a vacuum that draws fluid from pressure vessel 128 into the device. This feature evacuates pressure vessel 128. The device may further be configured to mix high-pressure and low-pressure flows together. This combined flow exits ejector 130 at its intermediate-pressure outlet (IP) and is infused back into conduit 106 through inlet line 132 at the same or similar pressure as found downstream of flow controller 108.

[0014] FIG. 5 shows a perspective view of one example of the fluid circuit 120 of FIG. 3 . This example includes a sensing line 150 and an instrument line 152 with a pressure regulator 154. Both lines 150, 152 may be coupled to a valve meter 156. The sensing line 150 can couple the valve meter 156 to the conduit 106 downstream of the flow controller 108. This configuration can provide feedback regarding downstream pressure, which is important for adjusting the position of the closure member 116 to ensure proper flow of the material 104 through the device, for example. The instrument line 152 can allow pressure from upstream of the flow controller 108 to operate the actuator 112. In one implementation, the pressure regulator 154 can significantly reduce the pressure of the inlet gas, for example, from 1000 psi to approximately 120 psi, for use by the flow controller 108.

[0015] FIG. 6 shows a perspective view of an exemplary structure of the flow control device 108. The structure can include a valve movement sensor 158 affixed to a mount 160. The mount 160 can be coupled to a base 162 by fasteners F, such as screws or bolts. The base 162 can support the valve body 110. As also shown, the base 162 can support a load generator 164, which can include a spring cartridge 166 and a pneumatic cylinder 168. In one implementation, the valve instrument 156 can embody a controller that senses downstream pressure. The controller 156 can act on the pneumatic cylinder 168 to position the closure member 116 ( FIG. 1 ) in its correct position and maintain the downstream pressure at a desired or predetermined level. Other components, such as a moving scale 170, can also be secured to the base 162. The moving scale 170 can embody part of a mechanical indicator having one or more parts attached to or integrated into the base 162 as a machined feature. However, the present disclosure also contemplates the use of display technology (eg, a screen, display, etc.) that can provide some type of visual interface for an observer to perceive the movement or position of closure member 26 (FIG. 1).

[0016] In view of the above, the improvements herein reduce the amount of natural gas (or other working medium) that a flow control device vents to the atmosphere. These improvements allow operators to comply with local regulations or standards. As an added benefit, the proposed design allows for the escaped gas to be reinjected back into the facility pipeline. This feature allows operators to monetize a product that is often "lost" as part of normal process or facility operations.

[0017] The following examples include particular elements or clauses to describe embodiments contemplated within the scope of this specification. These elements may be combined with other elements and clauses to similarly describe embodiments. This specification may include and contemplate other examples that occur to those skilled in the art. These other examples are within the scope of the claims, for example, if they have structural elements that do not differ from the literal language of the claims, or if they have equivalent structural elements that differ insignificantly from the literal language of the claims.

Claims

1. a recovery unit comprising: a collection circuit having an interface for capturing fluid from the envelope disposed around the valve; a pressure vessel coupled to the recovery circuit; a pump coupled to the pressure vessel, the pump configured to draw fluid from the pressure vessel and generate a flow at a pressure corresponding to a pressure downstream of the valve.

2. 10. The recovery unit of claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit configured to generate signals to activate and deactivate the pump in response to pressure within the pressure vessel.

3. 10. The recovery unit of claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit configured to generate an electrical signal that operates the pump in response to pressure within the pressure vessel.

4. 10. The collection unit of claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit configured to generate pneumatic signals for activating and deactivating the pump in response to pressure within the pressure vessel.

5. 10. The recovery unit of claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit comprising a valve interposed between the controller and the pump.

6. 10. The recovery unit of claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit comprising: a controller; a valve interposed between the controller and the pump; and a pressure regulator coupled upstream of the controller.

7. 10. The recovery unit of claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit comprising: a controller; a valve interposed between the controller and the pump; and a pressure regulator coupled upstream of the controller.

8. 10. The collection unit of claim 1, further comprising an inlet line coupled at a first end to the pump for receiving the flow, the inlet line configured having a second end for coupling to a conduit coupled downstream of the valve.

9. The recovery unit of claim 1 , wherein the pump comprises an electric pump.

10. The recovery unit of claim 1 , wherein the pump comprises an air pump.

11. The recovery unit of claim 1 , wherein the pump includes an ejector.

12. 1. A system comprising: a pressure vessel having a connection capable of interacting with a portion of a valve, the connection configured to direct escape gas exhaust from the portion of the valve into the pressure vessel; a pump system coupled to the pressure vessel, the pump and a control circuit for operating the pump, the control circuit configured to generate a signal in response to feedback from the pressure vessel, the signal causing the pump to discharge a flow comprising fluid from the pressure vessel.

13. The system of claim 12 , wherein the signal is a pneumatic signal.

14. The system of claim 12 , wherein the signal is an electrical signal.

15. The system of claim 12 , wherein the signal causes a valve to open or close.

16. 1. A method comprising: directing the fugitive emissions from the valve into a pressure vessel; energizing a pump in response to pressure within the pressure vessel; directing flow from the pump downstream of a flow control device disposed as part of a pipeline.

17. 17. The method of claim 16, further comprising directing fluid from the upstream side of the flow control device to the pump.

18. directing fluid from the upstream side of the flow control device to the pump; 17. The method of claim 16, further comprising: actuating a valve to allow the fluid to flow to the pump.

19. 17. The method of claim 16, wherein the flow is at a pressure corresponding to the pressure of the fluid in the pipeline.

20. The method of claim 16 , wherein the pump includes an ejector.

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