Energy exchange compressor for carbon capture

Abstract

A system for evacuating gases from a pig trap to a low pressure destination within a pipeline system is based on an energy exchange compressor that is driven by high pressure gas from a high pressure supply segment of the pipeline system. The energy exchange compressor can be constructed as a two-stage reciprocating compressor that includes a drive section and a control section in fluid communication with the high pressure supply segment through a high pressure intake line.

Description

[0001] ENERGY EXCHANGE COMPRESSOR FOR CARBON CAPTURE

[0002] Related Applications

[0003]

[0001] The present application claims the benefit of United States Provisional Patent Application Serial No. 63 / 523,576 filed June 27, 2023 and entitled, "Energy Exchange Compressor for Pipeline Pumpdown Operations,” the disclosure of which is herein incorporated by reference.

[0004] Field of the Invention

[0005]

[0002] The subject matter disclosed herein relates to greenhouse gas emissions control devices, and more particularly to systems and methods designed to mitigate greenhouse gas emissions from pigging and other pipeline operations.

[0006] Background

[0007]

[0003] Pipelines are often used to carry petroleum fluids over long distances. Devices referred to as “pigs” or “scrapers” are used on a periodic basis to examine pipelines for corrosion and damage, and to clean the pipeline of accumulated deposits from the petroleum products. The pig typically resembles a piston with an outer diameter that closely matches the inner diameter of the pipeline. Pressurized fluids - including the petroleum products flowing through the pipeline - can be used to push the pig through the pipeline.

[0008]

[0004] Often, the pigging process involves deploying a pig into the pipeline through a “pig launcher” that is connected as an adjacent component to the pipeline. The pig is retrieved from the pipeline at a receiving station, which is sometimes called a “pig receiver” or “pig trap.” In some applications, the launcher and receiver are configured to both launch and receive the pig.

[0005] It will be appreciated that the pig launcher and the pig receiver are isolated from the pressurized fluids in the pipeline during the process of loading the pig into the pig launcher and removing the pig from the pig receiver. Pressurized fluids are earned into the launcher through a “kicker” line that extends from the pipeline to the launching station. By opening and closing valves on the pipeline, kicker line and launching station, pressurized fluids can be diverted from the operational pipeline into the launching station to push the pig out of the launching station and through the pipeline. Similarly, the receiving station is connected to the pipeline through a series of valves that can be opened to temporarily divert the flow of fluids from the pipeline into the receiving station as the pig enters the receiving station. Once the pig has been captured within the receiving station, the valves can be manipulated to return flow to the pipeline.

[0009]

[0006] When the pig arrives at the receiving station the pressurized petroleum fluids are captured within the receiving station. To allow the pig to be safely removed through a door in the receiving station, the pressurized fluids are typically vented to the atmosphere. Once the pressure inside the receiving station has been equalized with the atmosphere, the door in the receiving station can be opened to permit the removal of the pig.

[0010]

[0007] Fugitive emission of petroleum fluids may also arise from compressor operations, where pressurized greenhouse gases may traverse packing glands and seals within the compressor before being vented to atmosphere through lower pressure areas of the compressor, such as the crankcase.

[0011]

[0008] In each case, the practice of venting pressurized petroleum fluids into the atmosphere presents an environmental concern. Petroleum fluids may include aggressive greenhouse gases such as carbon dioxide, methane (natural gas) or selected hydrocarbon species that are regulated as volatile organic compounds. There is, therefore, a need for an improved system for controlling hydrocarbon emissions from pipeline pigging and compressor operations.

[0012] SUMMARY OF THE INVENTION

[0013]

[0009] Embodiments disclosed herein are generally directed at a system for evacuating gases from a pig trap to a low pressure destination within a pipeline system using an energy exchange compressor that is driven by high pressure gas from a high pressure supply segment of the pipeline system. The energy exchange compressor can be constructed as a two-stage reciprocating compressor that includes a drive section and a control section in fluid communication with the high pressure supply segment through a high pressure intake line.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015]

[0010] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0016] [OH] FIG. 1 is a diagram illustrating the placement of an embodiment of the energy exchange compressor between high pressure and lower pressure pipeline segments.

[0017]

[0012] FIG. 2 provides a close-up diagram of the energy exchange compressor of FIG. 1 in which the energy exchange compressor includes a piston valve based control section.

[0018]

[0013] FIGS. 3A-3D depict the operation of the energy exchange compressor of FIG. 2.

[0019]

[0014] FIGS. 4A-4E depict the operation of an embodiment of the energy exchange compressor with a slide valve based control section.

[0015] FIG. 5 is a process flow diagram for a method for transferring captured gases within a pig trap.

[0020] WRITTEN DESCRIPTION

[0021]

[0016] The present disclosure is generally directed at systems and methods for transferring gases trapped in a pipeline segment, such as a pig catcher, to another pipeline or pipeline segment for downstream processing. The systems and methods disclosed herein reduce or eliminate the release or production of greenhouse gases that would otherwise be vented to atmosphere during routine pipeline maintenance operations. It will be appreciated however, that the embodiments disclosed herein can also be used to transfer gases from a low pressure source to a higher pressure destination, including fugitive gases from compressor operations. Gases trapped in crankcases, packing vents, and other low pressure regions in or around the compressor can be gathered and pressurized with an energy exchange compressor that is powered by high pressure gases produced by the intended operation of the compressor. Thus, in exemplary' embodiments, systems and methods disclosed herein find particular utility' in capturing and pressurizing hydrocarbon gases from a low pressure origin using available high pressure hydrocarbon gases so that the captured hydrocarbon gases can be reintroduced into the pipeline, compressor or other destination in a manner that is more environmentally responsible than venting the captured hydrocarbon gases to the atmosphere.

[0022]

[0017] Turning to FIG. 1, shown therein is an energy' exchange compressor 100 constructed and deployed in accordance with an exemplary embodiment. The energy exchange compressor 100 is generally used to transfer gases captured in a low pressure origin segment 102 to a destination segment 104, which may also be at a low pressure. It will be appreciated that the low pressure origin segment 102 can be a pig catcher, a pig launcher, or another pipeline segment, compressor, vessel or chamber that includes an isolated volume of gas. The energy exchange compressor 100 is driven by pressurized gases from a high pressure supply segment 106. The low pressure origin segment 102, low pressure destination segment 104 and high pressure supply segment 106 can each be part of the same pipeline system or each part of multiple, separate pipelines or vessels.

[0023]

[0018] As used herein in the context of a pipeline, the term “segment” refers to a portion of a pipeline that is separated from adjacent portions of the pipeline by a fluid isolation mechanism, such as a valve, compressor, or other intervening mechanism or chamber. The term generally “low pressure” refers to pressures below 300 pounds per square inch (gauge)(“psig”). The term generally “high pressure” refers to pressures above about 700 psig. It will be understood that the energy exchange compressor 100 can be connected to pipeline systems operating between and beyond these pressure ranges.

[0024]

[0019] In the embodiment depicted in FIG. 1, the low pressure origin segment 102 is connected to the low pressure destination segment 104 with an equalization line 108 that can be selectively opened, closed or throttled with one or more equalization valves 110. Although the equalization line 108 is shown connecting the low pressure origin segment 102 to a similar pig trap or launcher on the low pressure destination segment 104, it will be appreciated that the equalization line 108 can be connected to any low pressure pipeline segment, such as a suction line to a compressor. The equalization line 108 may also include a vent 112 that can be opened to release gases from the equalization line 108 to the atmosphere.

[0025]

[0020] The low pressure origin segment 102 is separated from the high pressure supply segment 106 with an isolation valve 114. A high pressure intake line 116 connects the high pressure supply segment 106 to the energy exchange compressor

[0026] 100. A low pressure inlet line 118 connects the low pressure origin segment 102 to the energy exchange compressor 100. An exhaust line 120 connects the energy exchange compressor 100 to the low pressure destination segment 104. A low pressure discharge line 122 also connects the energy exchange compressor 100 to the low pressure destination segment 104. In exemplary embodiments, the low pressure destination segment 104 is sized or configured such that its pressure remains relatively constant during the evacuation operation. As shown in FIG. 1, it may be useful to connect the low pressure discharge line 122 and the exhaust line 120 to different parts of the low pressure destination segment 104 that are separated by a valve or other barrier.

[0027]

[0021] Turning to FIG. 2, shown therein is an enlarged view of a first embodiment of the energy exchange compressor 100. The energy exchange compressor 100 includes a drive section 124, a control section 126, a first stage section 128, a second stage section 130 and a common shaft 132 that extends through each of the sections 124, 126, 128 and 130. The common shaft 132 can include a unitary' shaft or a plurality' of interconnected shaft segments. Each of the sections 124, 126, 128 and 130 of the energy exchange compressor 100 is generally configured as a cylinder in which a piston (sections 124, 128 and 130) or valve (section 126) reciprocates. Each section 124, 126, 128 and 130 is separated from adjacent sections by cylinder ends, as depicted in FIG. 2.

[0028]

[0022] The energy' exchange compressor 100 may further include a heat exchanger 134, an intake control valve 136 and an exhaust control valve 138 (depicted in FIG. 1). The heat exchanger 134 is configured to transfer the heat of compression with cooler high pressure gas, thereby reducing gas temperatures entering the second stage section 130. The intake control valve 136 can be manually or automatically adjusted to control the flow of high pressure drive gas from the high pressure supply segment 106 to the energy exchange compressor 100. The exhaust control valve 138 can be manually or automatically adjusted to control the flow of exhaust gas from the energy exchange compressor 100 to the low pressure segment 104.

[0029]

[0023] The control section 126 includes a high pressure inlet 140, a switching valve 142, a pair of control section drive line connectors 144a. 144b, and a pair of exhaust outlets 146a, 146b. The high pressure intake line 116 is connected to the high pressure inlet 140. A collar 148 secured to the shaft 132 inside the slide valve 142 pushes the switching valve 142 back and forth within the control section 126 as the shaft 132 reciprocates between first and second positions.

[0030]

[0024] The switching valve 142 is a piston that slides back and forth within the control section 126 to selectively couple the high pressure intake line 116 to one of the control section drive line connectors 144a, 144b, while simultaneously coupling the other of the control section drive line connectors 144a, 144b to the exhaust line 120 through one or both of the exhaust outlets 146a, 146b located on opposite sides of the piston switching valve 142. In this way, the high pressure gas from the high pressure intake line 116 enters the control section 126 and is directed around the outside of the piston switching valve 142 to one of the drive lines 150a, 150b, while the other drive line 150a, 150b communicates the discharge from the drive section 124 to the exhaust line 120 through one or both of the exhaust outlets 146a, 146b. The exhaust line 120 is connected to the low pressure destination segment 104. The exhaust control valve 138 can be used to throttle or block the passage of gases from the control section 126 to the low pressure destination segment 104.

[0025] The drive section 124 includes drive line connectors 152a, 152b and a drive piston 154 that is connected to the shaft 132. The drive line connectors 152a, 152b are located on opposite sides of the drive piston 154. The drive section 124 is in fluid communication with the control section 126 through drive lines 150a. 150b that extend from the control section drive line connectors 144a, 144b to the drive section drive line connectors 152a, 152b, respectively. Through cooperation with the switching valve 142, the drive piston 154 is forced to reciprocate back and forth within the drive section 124 as the high pressure gas from the high pressure supply segment 106 is switched between the first and second drive lines 150a, 150b.

[0031]

[0026] In this way, the drive piston 154 forces the shaft 132 between the first and second positions, which moves the switching valve 142 between first and second positions to sequentially and continuously reverse the flow of high pressure gas to the opposite side of the drive piston 154. When the switching valve 142 connects one of the drive lines 150a, 150b to the lower pressure exhaust line 120. the drive piston 154 forces the gases out of the drive section 124, through the interior of the control section 126 and into the exhaust line 120. The output of the drive piston 154 can be controlled by adjusting one or both of the intake and exhaust control valves 136. 138.

[0032]

[0027] The first stage section 128 includes a first stage piston 156 and a pair of first stage inlets 158a, 158b. The first stage inlets 158a, 158b are positioned on opposite sides of the first stage piston 156 and connected to the low pressure inlet line 118. The first stage inlets 158a, 158b each include a one-way first stage inlet check valve 160 that is configured to permit the unidirectional flow of gas into the first stage section 128, while preventing the passage of gas out of the first stage section 128. In some embodiments, the first stage inlet check valves 160 are configured to open when the pressure differential across the first stage inlet check valves 160 reaches about 5 psig.

[0028] The first stage section 128 also includes a pair of first stage outlets 162a, 162b on opposite sides of the first stage piston 156 that each include a first stage outlet check valve 164. The first stage outlet check valves 164 are configured to permit the unidirectional flow of gas out of the first stage section 128, while preventing the passage of gas back into the first stage 128. In some embodiments, the first stage outlet check valves 164 are configured to open when the pressure differential across the first stage outlet check valves 164 reaches about 90 psig.

[0033]

[0029] The first stage piston 156 is fixed in position on the shaft 132. As the shaft 132 reciprocates back and forth, the first stage piston 156 compresses the gas on alternating sides of the first stage piston 156. When the first stage piston 156 moves in a first direction, the first stage piston 156 compresses the gas on a first side of the first stage piston 156 until the pressure exceeds the opening pressure for the first stage outlet check valve 164 for the first stage outlet 162a. At the same time, the first stage piston 156 draws gas in through the first stage inlet 158b. When the direction of the shaft 132 changes, the first stage piston 156 compresses the gas on the second side of the first stage piston 156 while drawing in gas through the first stage inlet 158a. When the gas on the second side of the first stage piston 156 exceeds the opening force of the first stage outlet check valve 164, the gas is expelled through the first stage outlet 162b. In this way, the first stage section 128 is configured as a double-acting reciprocating compressor.

[0034]

[0030] In exemplary embodiments, the first stage section 128 and the first stage piston 156 are larger in diameter than the drive section 124 and drive piston 154. The larger surface area of the first stage piston 156 permits the first stage section 128 to operate efficiently under the lower pressures of the gas from the low pressure origin segment 102.

[0031] The second stage section 130 includes a second stage piston 166 and a pair of second stage inlets 168a, 168b positioned on opposite sides of the second stage piston 166. The second stage inlets 168a, 168b are connected to the first stage outlets 162a, 162b with an interstage hne 170. The second stage inlets 168a. 168b each include a second stage inlet check valve 172 that permits the flow of gas from the interstage line 170 into the second stage section 130, while prohibiting the flow of gas from the second stage section 130 back into the interstage line 170. In some embodiments, the second stage inlet check valves 172 are configured to open at about 90 psig.

[0035]

[0032] The second stage section 130 also includes a pair of second stage outlets 174a, 174b that each include a second stage outlet check valve 176. The second stage outlets 174a, 174b are positioned on opposite sides of the second stage piston 166. In some embodiments, the second stage outlet check valves 176 can be configured to open at about 300 psig to permit the flow of gas from the second stage section 130 into the low pressure discharge line 122, while prohibiting flow from the low pressure discharge line 122 back into the second stage section 130. The second stage piston 166 is smaller than the first stage piston 156 to accommodate the step-up in pressure between the first and second stage sections 128, 130.

[0036]

[0033] The second stage piston 166 is fixed to the shaft 132 and configured as a double-acting reciprocating compressor. During use, the second stage piston 166 reciprocates between first and second positions as the shaft 132 is driven back and forth. In a first direction, the second stage piston 166 compresses gas inside the first side of the second stage section 130 until the pressure meets or exceeds the line pressure in the low' pressure destination segment 104 and the gas is expelled through the second stage outlet 174a, 174b. While the second stage piston 166 is moving in the first direction, the second stage inlet check valve 172 for the second stage inlet 168b opens to admit gas from the interstage line 170 into the second stage section

[0037] 130. When the direction of the second stage piston 166 changes, the second stage piston 166 compresses the gas on the second side of the second stage section 130 until the pressure exceeds the opening pressure of the applicable second stage outlet check valve 176 and the gas is expelled through the second stage outlet 174b. The second stage outlets 174a. 174b are connected to the low pressure discharge line 122, which is in turn connected to the low pressure destination segment 104.

[0038]

[0034] FIGS. 3A-3D depict various states or positions of an embodiment of the energy exchange compressor 100 as the common shaft 132 and connected components reciprocate. In this embodiment, the switching valve 142 resembles the piston switching valve 142 of FIG. 2, except that the switching valve 142 is moved between first and second positions by a shuttle 149 that includes inboard and outboard collars 148a, 148b. The shuttle 149 is attached to the shaft 132 and reciprocates the switching valve 142 within a valve chamber 151 that includes ports that place the high pressure intake line 116 into fluid communication with one drive lines 150a, 150b depending on the position of the switching valve 142.

[0039]

[0035] In FIG. 3 A, the piston switching valve 142 is in a first, outboard position and the high pressure gas from the high pressure intake line 116 is directed around the annular space between the piston switching valve 142 and the cy lindrical body of the control section 126 to the drive line 150b. The high pressure gas enters the drive section 124 through the drive line connector 152b and forces the drive piston 154 in an inward direction, as depicted in FIG. 3B. As the drive piston 154 reaches the end of its inward stroke (as depicted in FIG. 3C), the outboard collar 148b pulls the piston switching valve 142 inward to couple the high pressure intake line 116 to the drive line 150a. The high pressure gas then pushes the drive piston 154 and common shaft 132 outward as depicted in FIG. 3D. Once the drive piston 154 approaches the end of its outward stroke, the inboard collar 148a returns the piston switching valve 142 to its initial position, depicted in FIG. 3A.

[0040]

[0036] Turning to FIGS. 4A-4E. shown therein is an embodiment of the energy exchange compressor 100 in which the switching valve 142 is a slide valve. In this embodiment, the control section 126 includes the high pressure inlet 140. the pair of control section drive line connectors 144a, 144b. and a single exhaust outlet 146. A collar 148 secured to the shaft 132 inside the slide valve 142 pushes the switching valve 142 back and forth within the control section 126 as the shaft 132 reciprocates between first and second positions.

[0041]

[0037] In this embodiment, the slide valve switching valve 142 alternately connects one of the drive lines connectors 144a, 144b with a single exhaust outlet 146. The slide valve 142 includes an interior that is hermetically isolated from the high pressure gases surrounding the slide valve 142 in the control section 126. In the first position, the slide valve 142 connects the exhaust outlet 146 to the first control section drive line connector 144a, such that pressurized gas from the high pressure inlet 140 can only pass through the second control section drive line connector 144b. In the second position, the switching valve 142 connects the exhaust outlet 146 to the second control section drive line connector 144b, while opening the first control section drive line connector 144a to the pressurized gas inside the control section 126 from the high pressure inlet 140.

[0042]

[0038] In FIG. 4A, the slide valve switching valve 142 is in a first position that couples the high pressure intake line 116 to the drive line 150a, while simultaneously coupling the drive line 150b to the exhaust line 120. As the high pressure gas enters the drive section 124 through the drive line connector 152a, the drive piston 154 is pushed outward, as depicted in FIG. 4B. As the movement of the drive piston 154 and shaft 132 continue outward, the collar 148 contacts the switching valve 142 and pushes the switching valve 142 to outward, as depicted in FIG. 4C. In this second position, the switching valve 142 couples the high pressure intake line 116 to the drive line 150b, while coupling the drive line 150a to the exhaust line 120. The high pressure gas from the high pressure intake line 116 then forces the drive piston 154 inward, as depicted in FIG. 4D. The drive piston 154. shaft 132 and other components connected to the shaft 132 continue the inward movement until the collar 148 shifts the switching valve 142 back to the first position, as depicted in FIG. 4E. The shaft 132, drive piston 152. first stage piston 156, and second stage piston 166 are thus reciprocated back and forth in response to the changing position of the switching valve 142.

[0043]

[0039] The optional heat exchanger 134 can be configured to reduce the temperature of the gas leaving the first stage outlets 162a, 162b before entering the second stage inlets 168a, 168b. As depicted in FIG. 2, the heat exchanger 134 is configured to transfer heat between the exhaust line 120, the low pressure discharge line 122, and the interstage line 170. The heat exchanger 134 can be a ty pical shell and tube design.

[0040] In the embodiments depicted in FIGS. 1-4. the first stage section 128 and drive section 124 are positioned between the control section 126 and the second stage section 130, with the drive section 124 positioned between the control section 126 and the first stage section 128. It will be appreciated that the particular arrangement of the various sections 124-130 can be rearranged in other embodiments. In some embodiments, the energy' exchange compressor 100 includes a single stage driven by the drive section 124 with an appropriately sized piston. In other embodiments, the energy' exchange compressor 100 includes three or more stages.

[0041] In some embodiments, the energy exchange compressor 100 includes one or more position sensors 180 that detect the reciprocating movement of the energy exchange compressor 100. For example, as depicted in FIG. 3 A, a pair of position sensors 180 can be located on opposite ends of the drive section 124 to detect the speed or frequency at which the drive piston 154 reciprocates within the drive section 124. The speed of the reciprocating movement of the various components connected to the shaft 132 can be used to assist with the control and operation of the energy exchange compressor 100.

[0044]

[0042] Thus, in exemplary embodiments, the energy exchange compressor 100 is configured to transfer gas from the lower pressure origin segment 102 (e.g., the pig trap) to the destination segment 104 (e.g., a suction line to a pipeline compressor) using energy (e.g., drive gas) from the high pressure supply segment 106. Turning to FIG. 5, shown therein is a process flowchart for an exemplary method 200 for transferring captured gases from a pig trap 102 to a low pressure destination segment 104. The method begins at step 202 when the pig trap 102 is isolated from the high pressure supply segment 106 by closing the isolation valve 114. Next, at step 204, the equalization valve 110 is opened and the pressure between the pig trap 102 is equalized with the low pressure destination segment 104. The equalization valve 110 is then closed.

[0045]

[0043] At step 206, the energy exchange compressor 100 is activated by opening the intake control valve 136 and exhaust control valve 138 to allow high pressure gas from the high pressure supply segment 106 to impart energy into the drive section 124 as the high pressure gas passes through the energy exchange compressor 100. Initially, the pressure differential between the pig trap 102 and the low pressure destination segment 104 is small and little energy is needed by the drive section 124 to reciprocate the first and second stage sections 128, 130. The exhaust control valve

[0046] 138 can be throttled to build sufficient back pressure to prevent the slide valve 142, drive piston 154, first stage piston 156 and second stage piston 166 from slamming into the ends of their respective cylinders or strokes per minute speed exceeding the design limitations.

[0047]

[0044] At step 208, the energy exchange compressor 100 draws gas out of the pig trap 102 and the pressure differential between the pig trap 102 and the low pressure destination segment 104 increases. Additional energy is then required to operate the energy exchange compressor 100. The intake and exhaust control valves 136, 138 can be automatically or manually adjusted to increase the throughput of gas from the high pressure intake line 116. In some embodiments, the intake and exhaust control valves 136, 138 are automatically actuated in response to the measured pressure differential between the low pressure inlet line 118 and the low pressure discharge line 122.

[0048]

[0045] Once the pressure inside the pig trap 102 falls below a threshold level (e.g., 5 psig). the energy exchange compressor 100 can be turned off by closing the intake and exhaust control valves 136, 138 to isolate the energy exchange compressor 100 from the high pressure intake line 116 and low pressure destination segment 104. At step 210, residual low pressure gas in the pig trap 102 can be vented to atmosphere or otherwise removed to a container through the vent 112. At step 212, the pig trap 102 can be opened to remove the pig or otherwise service the pig trap 102.

[0049]

[0046] In this way, exemplary' embodiments make use of an energy exchange compressor 100 that can be driven by a source of high pressure gas from an adjacent or nearby pipeline rather than relying on external sources of energy. Studies have shown that the energy exchange compressor 100 can reduce greenhouse gas emissions by more than 99.5% compared to the conventional method of venting the pig trap 102 to atmosphere. Compared to evacuation systems that rely on external internal combustion-powered generators, the energy exchange compressor 100 can reduce greenhouse gas emissions by more than 73%. Accordingly, the energy exchange compressor 100 provides an efficient and environmentally sound system for removing greenhouse gases from a pig trap 102 or other low pressure origin segment of a pipeline or vessel.

[0050]

[0047] It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.

Claims

What is claimed is:

1. A system for transferring gases from a pig trap or other low pressure origin segment to a destination segment, the system comprising: a high pressure supply segment that includes high pressure natural gas; and an energy exchange compressor connected between the high pressure supply segment and the destination segment, wherein the energy exchange compressor is driven by the high pressure natural gas from the high pressure supply segment and wherein the energy exchange compressor comprises: a drive section; a control section; a first stage section; a second stage section; a common shaft extending through the drive section, the control section, the first stage section and the second stage section; and wherein the control section comprises a switching valve connected to the common shaft.

2. The system of claim 1, wherein the high pressure supply segment is separated from the pig trap by an isolation valve.

3. The system of claim 1, wherein the switching valve is a sliding valve.

4. The system of claim 1, wherein the switching valve is a piston valve.

5. The system of claim 1. wherein the drive section includes a drive piston connected to the shaft.

6. The system of claim 5, wherein the drive section is connected to the control section with one or more drive lines.

7. The system of claim 1, wherein the control section is connected to the high pressure supply segment with a high pressure intake line.

8. The system of claim 7. wherein the second stage section is connected to the destination segment with a low pressure discharge line.

9. The system of claim 8, wherein the first stage is connected to the second stage with an interstage line.

10. The system of claim 9 further comprising a heat exchanger, wherein the heat exchanger is connected on the interstage line and the high pressure intake line.

11. The system of claim 10, wherein the first stage section includes a first stage piston and the second stage section includes a second stage piston that is smaller than the first stage piston.

12. The system of claim 11, wherein the drive section includes a drive piston that is larger than the second stage piston and smaller than the first stage piston.

13. The system of claim 11, further comprising an exhaust line connected between the control section and the low pressure destination segment.

14. The system of claim 13 further comprising an exhaust control valve on the exhaust line.

15. The system of claim 14 further comprising an intake control valve on the high pressure intake line.

16. The system of claim 1, wherein the drive section is located between the control section and the first stage section.

17. The system of claim 16, wherein the first stage section is located between the drive section and the second stage section.

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