Recombination of the working fluid 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 an extensive network of pipes, tanks, generators, and other equipment. Oil and gas facilities may use pneumatic or electro-pneumatic control valves to regulate the flow of hydrocarbons such as natural gas. These facilities may direct line pressure to the control valve as an operating medium or "actuating" medium for an on-board pneumatic actuator. This feature is advantageous in remote locations because power such as electricity may be scarce or in short supply. However, while convenient, flow control devices often vent or release this operating 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 for recovering at least a majority, if not all, of this "lost" operating medium. Particular interest lies in embodiments that can collect the operating medium and reinject it back into the facility's pipeline (or other parts of the facility system or network). These embodiments can use the pressure differential across the flow control device to raise the pressure of the operating medium to a level seen downstream of the flow control device. This feature can prevent product loss and reduce greenhouse gas emissions.

Brief Description of the Drawings

[0003] This specification refers to the following drawings. [Figure 1] A schematic diagram of a recovery unit. [Figure 2] A schematic diagram of an example of a fluid circuit for use in a recovery unit. [Figure 3] A schematic diagram of an example of a fluid circuit for use in a recovery unit. [Figure 4]This is a schematic diagram of an example of a fluid circuit for use in a recovery unit. [Figure 5] Figure 3 is a schematic diagram of an example of a fluid circuit. [Figure 6] This figure shows an example of a flow rate control device.

[0004] These drawings and any descriptions herein represent examples that may disclose or illustrate the invention. These embodiments include best modes and enable those skilled in the art to carry out the invention, including fabricating and using any device or system and performing any incorporated methods. The drawings are not to a constant scale unless otherwise noted in the description. Elements in each example may appear in one or more of several figures, or in combination of several figures. The drawings may use similar reference numerals to indicate identical or corresponding elements. Each method is merely illustrative and may be modified, for example, by rearranging, adding, removing, and / or changing individual steps or stages. In this specification, such stages, 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 be used to exclude the plural form of such designation unless the specification expressly states or describes such exclusion. Similarly, references to “one embodiment” or “one implementation” should not be construed as excluding the existence of additional embodiments or implementations that also incorporate the enumerated features. [Modes for carrying out the invention]

[0005] Next, the features of each example shown in the above drawings will be described. These features can improve operator compliance and profitability. Operators are keen to minimize 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, in general, to be good environmental managers. As described herein, each example shows a fluid circuit that can capture a fluid such as natural gas from various locations along the operator's pipeline network. These circuits protect this natural gas from the atmosphere and, in fact, can 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] Figure 1 shows an example of a recovery unit 100. This embodiment 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 extends from the actuator 112 and can position a closing member 116 close to the seat 118. In one implementation, the recovery unit 100 may have a fluid circuit 120 coupled to the conduits 106 on both sides of the flow control device 108.

[0007] In general, the recovery unit 100 may be configured to recover gases that are often lost into the atmosphere. These configurations may incorporate components that can operate with this “lost” gas. These components can capture lost gases, such as escape emissions or gases released during normal process operation. The components may also increase the pressure of the captured gas, allowing the operator to reinject the pressurized gas back into those processes. These features are beneficial because they allow the operator to prevent direct emissions of greenhouse gases while realizing revenue from the “reinjected” gas.

[0008] The distribution system 102 may be configured to deliver or move resources. These configurations can embody extensive infrastructure. The materials 104 may also include gases, liquids, solids, or mixtures. The conduits 106 may often include pipes or pipelines connected to pumps, boilers, etc. The pipes may also be connected to tanks or reservoirs. In many facilities, this system forms a complex network.

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

[0010] The fluid circuit 120 may be configured to couple with the upstream and downstream pressures 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] Figure 2 shows a schematic diagram of an example of a fluid circuit 120. This example includes a recovery circuit 122 having components, for example, an interface 124 and a line 126. Components 124, 126 may guide gas from within or around the flow control device 108 to a pressure vessel 128, such as a tank or reservoir. In one implementation, the interface 124 can form an envelope around all or part of the flow control device 108. The envelope can capture “escape” gas from the device, for example, from a packing, exhaust port, or other area that can be vented to the atmosphere. This escape gas can enter the pressure vessel 128 through line 126. A pump 130 may connect the pressure vessel 128 to an injection line 132 that connects to a conduit 106 downstream of the flow control device 108. The pump 130 may require power, for example, an electric or pneumatic source. A control circuit 134 may be coupled to the pump 130. The control circuit 134 may include a power source 136, such as a battery or mains power supply available on-site. The power source 136 can energize the controller 138. In one implementation, the controller 138 may receive feedback defining the operating parameters of the fluid circuit 120. These operating parameters may include, for example, a “tank” pressure corresponding to the pressure of the fluid in the pressure vessel 128. The controller 138 may compare the pressure to a threshold. A pressure above the threshold may 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 adjust the state of the pump 130. When it is “on,” i.e., operating, the pump 130 can draw stoichiometric gas from the pressure vessel 128. The pump 130 may increase the pressure of the stoichiometric gas so that it can flow back into the conduit 106 through the injection line 132 at a pressure equal to or similar to the pressure seen downstream of the flow control device 108, for example. The controller 138 can, for example, turn off or disable the pump 130 in response to a tank pressure below a threshold. This allows escaping gas to fill the pressure vessel 128.

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

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

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

[0015] Figure 6 shows a perspective view of an exemplary structure of a flow control device 108. This structure may include a valve movement sensor 158 fixed 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 a valve body 110. As also shown, the base 162 may support a load generator 164, which may include a spring cartridge 166 and a pneumatic cylinder 168. In one implementation, the valve instrument 156 may embody a controller that senses the downstream pressure. The controller 156 can act on the pneumatic cylinder 168 to position the closing member 116 (Figure 1) in its correct position and maintain the downstream pressure at a desired or predetermined level. Other components, such as a movement scale 170, may also be fixed to the base 162. The movement scale 170 may embody part of a mechanical indicator having one or more parts that are mounted to or integrated with the base 162 as machined features. However, this disclosure also intends to use display technology (e.g., a screen, display, etc.) that can provide some type of visual interface for an observer to perceive the movement or position of the closing member 26 (Figure 1).

[0016] Considering the above, the improvements described herein reduce the amount of natural gas (or other working fluid) that the flow control device vents to the atmosphere. These improvements enable operators to comply with local regulations or standards. As an additional benefit, the proposed design allows escaped gas to be reinjected back into the facility pipeline. This feature enables operators to monetize products that are often "lost" as part of normal process or facility operations.

[0017] The following examples include specific elements or sections for illustrating embodiments intended within the scope of this specification. These elements may be combined with other elements and sections to similarly illustrate embodiments. This specification includes and may include other embodiments conceived by those skilled in the art. These other embodiments are within the scope of the claims, for example, if they have structural elements that are no different from the literal wording of the claims, or equivalent structural elements that are substantially different from the literal wording of the claims.

Claims

1. It is a recovery unit, A recovery circuit having an interface for capturing fluid from an envelope positioned around a first valve, A pressure vessel coupled to the recovery circuit, A pump coupled to the pressure vessel, configured to draw fluid from the pressure vessel and generate a flow at a pressure corresponding to the pressure downstream of the first valve, A control circuit coupled to the pressure vessel and the pump, comprising: a controller; a second valve inserted between the controller and the pump; and a pressure regulator coupled to the upstream side of the controller. A recovery unit equipped with a recovery unit.

2. The recovery unit according to claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit configured to generate signals for operating and stopping the pump in response to the pressure in the pressure vessel.

3. The recovery unit according to claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit configured to generate an electrical signal for operating the pump in response to the pressure in the pressure vessel.

4. The recovery unit according to claim 1, further comprising a control circuit coupled to the pressure vessel and the pump, the control circuit configured to generate pneumatic signals for operating and stopping the pump in response to the pressure in the pressure vessel.

5. The recovery unit according to claim 1, further comprising an injection line connected to the pump at a first end for receiving the flow, the injection line having a second end for connecting to a conduit connected downstream of the valve.

6. The recovery unit according to claim 1, wherein the pump includes an electric pump.

7. The recovery unit according to claim 1, wherein the pump includes an air pump.

8. The recovery unit according to claim 1, wherein the pump includes an ejector.

9. It is a system, A pressure vessel having a connecting portion that can interact with a portion of a first valve, wherein the connecting portion is configured to guide the escape gas discharge from the portion of the first valve into the pressure vessel, A pump system coupled to the pressure vessel, comprising a pump and a control circuit for operating the pump, The control circuit comprises a controller, a second valve inserted between the controller and the pump, and a pressure regulator coupled to the upstream side of the controller. The control circuit is configured to generate a signal in response to feedback from the pressure vessel, and the signal causes the pump to discharge a flow containing fluid from the pressure vessel, comprising a pump system.

10. The system according to claim 9, wherein the signal is an air pressure signal.

11. The system according to claim 9, wherein the signal is an electrical signal.

12. The system according to claim 9, wherein the aforementioned signal causes a valve to open or close.

13. It is a method, The escape discharge is guided into the pressure vessel from the flow control device equipped with the first valve, The controller energizes the pump in response to the pressure inside the pressure vessel, The flow from the pump is guided downstream of the flow control device, which is positioned as part of the pipeline. A second valve inserted between the controller and the pump, and a pressure regulator coupled to the upstream side of the controller, transport pressure from the conduit connected to the upstream side of the flow control device, Methods that include...

14. The method according to claim 13, further comprising guiding fluid to the pump from the upstream side of the flow control device.

15. The fluid is guided to the pump from the upstream side of the flow control device, The method according to claim 13, further comprising acting on a valve to allow the fluid to flow to the pump.

16. The method according to claim 13, wherein the flow is at a pressure corresponding to the pressure of the fluid in the pipeline.

17. The method according to claim 13, wherein the pump includes an ejector.

18. A method, To guide the escaped waste into the pressure vessel from the first valve, The pump is energized in response to the pressure inside the pressure vessel, The flow from the pump is guided downstream of the first valve, which is positioned as part of the pipeline. The fluid is guided from the upstream side of the first valve to the pump, Methods that include...

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