US20220196003A1

US20220196003A1 - Gas handling system and method for efficiently managing changes in gaseous conditions

Info

Publication number: US20220196003A1
Application number: US17/691,811
Authority: US
Inventors: Todd Steven Abbot Gibbs
Original assignee: Atlas Copco Comptec LLC
Current assignee: Atlas Copco Comptec LLC
Priority date: 2015-04-30
Filing date: 2022-03-10
Publication date: 2022-06-23
Also published as: CN205805860U; US20220196004A1; US20160319810A1; KR102562422B1; EP3289292A4; KR20180004198A; CN106089637A; JP6832869B2; WO2016176006A1; JP2018520306A; EP3289292A1

Abstract

A system and method is provided for efficiently managing the compression of gas depending on the operating conditions and operating mode of the compression system, wherein the system includes a booster compressor, a booster compressor bypass, a conduit connected to the booster compressor and the booster compressor bypass conduit, a means for selectively directing the flow of the gas based on current operating conditions, to the booster compressor bypass or the booster compressor and a baseline compressor connected to both the booster compressor and the booster compressor bypass conduit.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent application Ser. No. 15/091,908, filed Apr. 4, 2016, and entitled “A GAS HANDLING SYSTEM AND METHOD FOR EFFICIENTLY MANAGING CHANGES IN GASEOUS CONDITIONS ,” which claims the benefit of and priority to U.S. patent application Ser. No. 62/155129 filed on Apr. 30, 2015, entitled A GAS HANDLING SYSTEM AND METHOD FOR EFFICIENTLY MANAGING CHANGES IN GASEOUS CONDITIONS, the contents of which are hereby incorporated by reference.

FIELD OF TECHNOLOGY

The following relates to systems and methods for gas handling systems, and more specifically to liquefied natural gas (LNG) or liquefied petroleum gas (LPG) gas handling systems having a gas compression system with an increased operating efficiency and a methods for managing changes in the environmental conditions of the gas handling system.

BACKGROUND

Liquefied natural gas (LNG) and liquefied petroleum gas (LPG) may be produced by cooling natural gas or petroleum gas into a liquid state using cryogenic cooling techniques. By condensing the gas into a liquid at a cryogenic temperature, the LNG or LPG can be stored in tanks or reservoirs, maintained as a liquid and transported long distances to a desired final destination, where the LNG or LPG can be re-gasified, pressurized and used by equipment or vehicles that consume the gas.
In order to manage, use or transport the liquefied gases stored in the storage tanks and reservoirs, the LNG or LPG may need to undergo one or more compression steps in an effort to increase the LPG or LNG to an operating pressure of the system employing the LNG or LPG. Current compression methods and systems are considered to be inefficient. Inefficient systems and methods rely on a single compressor to handle the entire compression workload in order to compress the LNG or LPG to a desired pressure. Operating conditions of systems utilizing an LNG or LPG system are known to vary dramatically depending on the operation modes being utilized by these complex LNG or LPG systems, at any particular moment. Under a system that utilizes a single compressor to handle the management of the gases, a compressor must be installed that is capable of handling the expected maximum input of LNG or LPG to the compression system and compressing it to the maximum required pressure. If a compressor is employed that cannot handle all variable changes to the operating condition that may occur, the single compressor may be overwhelmed and unable to handle the most extreme changes in operating conditions, and thus fail to operate sufficiently under all conditions.
In systems that rely on a single compressor to handle larger volumes of LNG or LPG, the compressor may be very large in size and use more power to operate than smaller compressors. Moreover, when a single compressor is the only available option for every operation mode of the system, the compressor must function continuously without being able to enter a low power or energy saving state. The gaseous compression system can be particularly energy inefficient to constantly run due to the oversized, overpowered compressor operating at all times, even during normal operating conditions where a smaller, more energy efficient compressor would suffice.
Thus, a need exists for a gas handling system and method that is able to dynamically adjust the compressors being utilized based on the current operating conditions, reducing the overall operating energy requirements of the compressors in the system and increasing the efficiency of the LNG or LPG compression.

BRIEF SUMMARY

A first aspect of this disclosure relates to a gas compression system comprising a booster compressor, a booster compressor bypass conduit, a conduit connected to the booster compressor and the booster compressor bypass conduit, wherein the conduit selectively directs the flow of gas based on current operating conditions to the booster compressor bypass or the booster compressor and a baseline compressor connected to both the booster compressor and the booster compressor bypass conduit.
A second aspect of the disclosure relates to a method for compressing gas comprising the steps of providing a booster compressor, providing a booster compressor bypass, selecting an operating mode from a first operating mode or a second operating mode, wherein the first operating mode is directing the gas through the booster compressor bypass and the second operating mode directing the gas to the booster compressor, compressing the gas into a compressed gas, and for both modes providing a baseline compressor receiving the gas from either the booster compressor bypass or the compressed gas from the booster compressor and compressing, by the baseline compressor, the gas or the compressed gas.
The foregoing and other features of construction and operation will be more readily understood and fully appreciated from the following detailed disclosure, taken in conjunction with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

FIG. 1a depicts a schematic view of an embodiment of a gas compression system;

FIG. 2b depicts a schematic view of an alternative embodiment of the gas compression system of FIG. 1 a;

FIG. 2 depicts a schematic view of another alternative embodiment of a gas compression system;

FIG. 3 depicts a schematic view of yet another alternative embodiment of a gas compression system;

FIG. 4 depicts an embodiment of a computing system of a gas compression system; and

FIG. 5 depicts a schematic view of an alternative gas compression system comprising a plurality of booster compressors.

DETAILED DESCRIPTION

A detailed description of the hereinafter described embodiments of the disclosed apparatus, method, and system are presented herein by way of exemplification and not limitation with reference to the Figures. Although certain embodiments are shown and described in detail, it should be understood that various changes and modifications may be made without departing from the scope of the appended claims. The scope of the present disclosure will in no way be limited to the number of constituting components, the materials thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of embodiments of the present disclosure.
As a preface to the detailed description, it should be noted that, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
Referring to the drawings, the schematic of FIG. 1a describes a compression system 100 which may be implemented or integrated into a system for managing, controlling, utilizing, transporting or delivering gases, such as from LNG or LPG systems. The embodiments of the compression systems described below and depicted in the figures of this application may be applied to numerous different types of natural gas, LNG or LPG systems, including, but not limited to LNG or LPG carriers, including LNG/LPG carrier propulsion systems, reliquefaction systems and LPG or LNG send out systems, as well as an LNG/LPG plant's liquefaction or purification facilities. Embodiments of the compression systems described below may also be integrated into systems for other LPG or LNG vehicles having an engine powered using natural gas, petroleum gas, and filling stations or facilities used to deliver the LNG or LPG to the carriers, vehicles and consumers.
Referring to FIG. 1a , embodiments of the compression system 100 may receive a stream of compressed or uncompressed natural gas or petroleum gas via a conduit 101. The conduit 101 may transport the stream of natural gas or petroleum gas from a source such as a reservoir or storage tank. In some embodiments, the reservoir or storage tank may be filled with LNG or LPG. In other embodiments, the source of the gases entering the compression system 100 may be entering the compression system 100 from an upstream process or system that may have utilized the LNG or LPG prior to the arrival at the compression system 100, via conduit 101. As the gas enters the compression system 100 through conduit 101, the gas may reach a junction point 102, wherein the gas may enter either the booster compressor 105 or the gas may enter a booster compressor bypass 103. Gas entering the booster compressor bypass 103 may avoid the booster compressor 105.
Embodiments of the compression system 100 may employ the use of a booster compressor bypass 103 in order to avoid the use of the booster compressor 105 during certain operating conditions. For example, under operating conditions wherein the gas entering the system 100 via conduit 101 may be capable of being adequately compressed and managed by system 100 without the assistance of the booster compressor 105, the booster compressor 105 may be bypassed. Conditions that are capable of being managed by system 100 without the implementation of the booster compressor 105 or additional auxiliary equipment supplementing the compression capabilities of the default compression system 100, may be referred to as baseline conditions.
Embodiments of a baseline condition may be a user defined or system defined value, or range of values, relating to the environment of the compression system 100, wherein the system may adequately operate without employing additional auxiliary equipment, such as the booster compressor 105. Baseline conditions may vary depending on the setup of the compression system 100 embodiments and the overall capabilities of the equipment provided within the compression system. The overall capabilities of each system embodiment may change depending on the configuration of the compression system and the equipment performing the functions of the compression system.
A user may configure the baseline conditions of the embodiments of the compression systems disclosed differently, depending on the environmental conditions a compression system may be capable of operating under. Environmental conditions a user may take into account when configuring the baseline conditions may include values or ranges of values for variables including but not limited to the volume of gas entering the system 100, the temperature of the system, the temperature of the gas, the operating time, a set interval of time, the energy consumption of the default equipment within compression system and the maximum operating capacity of equipment under the baseline conditions.
Moreover, environmental conditions may be monitored and measured in the compression system 100 using one or more sensors placed within the compression system 100. For example, one or more pressure sensors, thermal sensors, or temperature sensors may be placed within the conduits of the compression system 100 to transmit the environmental condition data relating to the measurement of operating environment and conditions of the gases flowing through the system. In other embodiments, one or more sensors may be equipped or integrated into the baseline compressor 109, booster compressor 105, or heat exchangers 111, 112 in order to identify that the system 100 is operating within the baseline conditions. In some embodiments, the data received by the sensors within the compression system 100 may be transmitted to a computing system such as control panel or kiosk being used, maintained or observed by an operator or administrator of the compression system 100.
FIG. 4 illustrates a computer system 490 used for receiving the transmission of data and information relating to the environmental conditions of the gas compression system and activating one or more operating modes, in accordance with embodiments of the present disclosure. The computer system 490 may comprise a processor 491, an input device 492 coupled to the processor 491, an output device 493 coupled to the processor 491, and memory devices 494 and 495 each coupled to the processor 491. The input device 492 may be, inter alia, a keyboard, a mouse, etc. The output device 493 may be, inter alia, a printer, a plotter, a computer screen, a magnetic tape, a removable hard disk, a floppy disk, etc. The memory devices 494 and 495 may be, inter alia, a hard disk, a floppy disk, a magnetic tape, an optical storage such as a compact disc (CD) or a digital video disc (DVD), a dynamic random access memory (DRAM), a read-only memory (ROM), etc. The memory device 495 may include a computer code 497 which may be a computer program that comprises computer-executable instructions. The computer code 497 includes software or program instructions that may record and display environmental conditions inside the gas compression system and may further selectively activate one or more of the operating modes described in this disclosure in response to the environmental condition data provided to the computing system. The processor 491 executes the computer code 497. The memory device 494 includes input data 496. The input data 496 includes input required by the computer code 897. The output device 493 displays output from the computer code 497. Either or both memory devices 494 and 495 (or one or more additional memory devices not shown in FIG. 4) may be used as a computer usable storage medium (or program storage device) having a computer readable program embodied therein and/or having other data stored therein, wherein the computer readable program comprises the computer code 497. Generally, a computer program product (or, alternatively, an article of manufacture) of the computer system 490 may comprise said computer usable storage medium (or said program storage device).
While FIG. 4 depicts the computer system 490 as a particular configuration of hardware and software, any configuration of hardware and software, as would be known to a person of ordinary skill in the art, may be utilized for the purposes stated supra in conjunction with the particular computer system 490 of FIG. 4. For example, the memory devices 494 and 495 may be portions of a single memory device rather than separate memory devices.
In some embodiments, rather than being stored and accessed from a hard drive, optical disc or other writeable, rewriteable, or removable hardware memory device 495, stored computer program code 497 may be stored on a static, nonremovable, read-only storage medium such as a Read-Only Memory (ROM) device, or may be accessed by processor 491 directly from such a static, nonremovable, read-only medium. Similarly, in some embodiments, stored computer program code 497 may be stored as computer-readable firmware, or may be accessed by processor 491 directly from such firmware, rather than from a more dynamic or removable hardware data-storage device 495, such as a hard drive or optical disc.
Embodiments of the compression system 100 may include a plurality of operating modes. This plurality of operating modes may vary depending on the configurations of the equipment in the compression system. In embodiments having more complex configurations, the number of operating modes may be greater than simpler or less complex systems. The plurality of operating modes may also vary depending upon the changes or fluctuations in operating conditions experienced by the compression system. For instance, a system that experiences a wider array of operating conditions during the operation of the compression system 100, may include more operating modes to select from when a particular operating condition is present in the compression system. Likewise embodiments of compression systems 100 that experience less variation in operating conditions may be programmed with a more limited number of operating modes. In some embodiments, the computing system, control panel or kiosk receiving data from the sensors may automatically select and activate one or more of the operating modes described below in response to the changes in environmental conditions recorded by one or more of the sensors present in the gas compression system. In alternative embodiments, a user or administrator of the gas compression system may manually select of the operating modes described herein in response to the changes in the environmental conditions present in the gas compression system and transmitted to a computing system receiving and monitoring the environmental conditions recorded by one or more sensors.
In some embodiments, the default operating mode may be selected when baseline conditions are present within the system. Embodiments of the system 100 operating at baseline conditions may consider this default operating mode to be its first operating mode. In the first operating mode, the stream of compressed or uncompressed gas entering the system 100 through conduit 101 may be selectively directed to continue through the bypass 103 and avoid the booster compressor 105. By avoiding the booster compressor 105 in the first operating mode, the booster compressor 105 may remain in a low power state or in an off state, or if previously activated, the change from a second operating mode back to the first operating mode may cause the compression system to perform the step of switching the booster compressor from an activated state to a low power state. The avoidance of the booster compressor 105 under baseline operating conditions may be useful for reducing the energy consumption of the compression system 100. After exiting the bypass 103, the gas may enter conduit 107. The conduits in this application are labelled separately for discussion and identification purposes, however in some embodiments the conduits 101, 103 and 107 may be a one continuous conduit passing through each of the components of the gas compression described herein and depicted in FIGS. 1 a to 3.
The gas exiting conduit 103 and being transported along conduit 107 may enter an inlet for baseline compressor 109. A baseline compressor 109 may be any compressor operational in the compression system 100 under baseline conditions. The baseline compressor 109 may be the compressor handling the compression and discharge of gas entering and exiting the system 100 without further assistance from auxiliary equipment under baseline conditions. In some embodiments, the baseline compressor may be referred to as a low duty compressor. The low duty compressor may be a single stage or a multi-stage compressor. The type of low duty compressor present in the compression system may depend on the overall system the compression system 100 is integrated into. For example, a low-duty compressor may have one to four stages or more. For instance, in an embodiment using a steam turbine propulsion system a 1-stage low duty compressor may be present, whereas a dual fuel diesel-electric (DFDE) propulsion system, such as those used for LNG carriers, the low duty compressor may be a 2-stage or 4-stage compressor.
Referring back to FIG. 1a , the gas entering the inlet of baseline compressor 109 may undergo a pre-selected or predetermined amount compression to reach the requisite or desired pressure requirements of a LNG,LPG or any other system that the compression system 100 is a part of. Once the gas inside the baseline compressor has reached the proper compression levels, the compressed gas in conduit 110 may be discharged from the compression system 100 and further transported to the desired destination, machinery, engine or equipment for further use or storage downstream from the compression system 100. In addition, the compressed gas in conduit 110 may exit an outlet and enter an inlet of another compressor for further compression in a compression system.
Embodiments of a baseline compressor 109 may be any type of compressor utilized within LNG,LPG or other gas-utilizing systems for the purposes of compression. Examples of compressors used may include dynamic compressors such as centrifugal or axial compressors. Other compressors that may be used in the compression system 100 may include reciprocal or rotary compressors. Types of reciprocating compressors may include but are not limited to diaphragm, double acting or single acting compressors, while types of rotary compressors may include lobe, helical-screw, liquid ring, scroll or sliding vane compressors.
Embodiments of system 100 may further include a plurality of one or more additional operating modes beyond the first operating mode. Each different operating mode may be separately initiated when one or more variables describing the environmental conditions of the system's 100 baseline conditions extends above or below the value, or range of values, programmed or set by the user or system. Each of the different operating modes may be referred to by a name or number. For example, each subsequent operating mode may be referred to as a second, third, fourth, fifth, sixth, etc. or by a descriptive name, such as the booster operating mode, low power operating mode, supplementary operating mode, liquefaction operating mode, or any other descriptive title that may indicate the purpose of the operating mode being engaged by the compression system.
There may be no limit to the number of operating modes that may be programmed, selectable or activated by the compression system 100 in response to different variations in the baseline conditions or environmental conditions present in the compression system. Fluctuations in baseline operating conditions may occur frequently, infrequently or at set intervals based on the type of LNG,LPG or other gaseous system the compression system 100 is connected to. The additional systems of the LNG,LPG or other gaseous systems may continuously activate or deactivate and the effects of those additional systems may cause changes in the environmental conditions present in the compression system 100. In response to the changes, the compression system 100 may respond by triggering, activating, initiating or executing one or more of the different operating modes programmed to become activated in response to the environmental changes of the compression system.
Under circumstances where the environmental conditions inside the compression system 100 may cause another operating mode to activate, additional equipment connected to the compression system 100 may activate in a manner selected, designated or programmed by a user or by the system itself, either manually or automatically. For instance, in some embodiments, a second or subsequent operating mode may activate the booster compressor 105 to assist the baseline compressor 109 with the compression of the gases introduced into the system 100. A booster compressor 105 may refer to any type of compressor which may provide a temporary increase to the pressure in the gas compression system and additional compression beyond the capabilities of compressors operating under baseline conditions, to meet a target pressure for compressed gas exiting the gas compression system. Embodiments of the booster compressor discharge into the inlet or suction line of another compressor. Embodiments of the booster compressor 105 in the system 100 may discharge the gases compressed by the booster compressor 105 into the inlet of the baseline compressor 109 for further compression via the intermediate conduit 107.
In one or more embodiments of system 100, where an operating mode has activated, for example in response to an environmental condition present in the gas compression system 100 is outside of a pre-programmed or predetermined value or range of values, the gases arriving to the system 100 via conduit 101 may be selectively directed to travel to the booster compressor 105, instead of the booster compressor bypass 103 used in the first operating mode. As the gases enter the booster compressor 105, they may be compressed to an intermediate pressure that may be manageable by the baseline compressor 109. This preliminary compression step may assist the baseline compressor both by reducing a volume of gas going to the baseline compressor 109 and by decreasing the overall amount of compression to be performed by the baseline compressor, in order to meet the pressure requirements of the discharged compressed gas in conduit 110. Subsequently, the baseline compressor 109 receiving the intermediate compressed gas from the booster compressor 105 discharge, may further compress the gases to achieve the compression system's 100 target level of compression in conduit 110.
For example, under the baseline conditions, the first operating mode of system 100 may remain active when the system operates under a specified temperature or range of temperatures. When the temperature of the system 100 fluctuates above or below the temperature range settings programmed for the baseline conditions, a second operating mode may be initiated or activated by the gas compression system. In this example, as the temperature rises beyond the baseline conditions, the volume of the gas entering the compression system 100 may increase to a level that is beyond the capabilities of the baseline compressor 109 to properly compress on it own in order to meet the required discharge pressure in conduit 110 of the LNG, LPG or other gas system. In some embodiments, the second operating mode may initiate a second compressor, such as the booster compressor 105 to compensate for the rise in the volume of gas, due to the temperature fluctuation beyond the baseline conditions. In this embodiment, once the booster compressor 105 is activated, the booster compressor 105 may initially compress the gases entering the compression system to an intermediate pressure that is manageable by the baseline compressor. In some embodiments, the compressed gases discharged from the booster compressor 105, may have a pressure that is greater than the pressure of the gases entering the compression system 100 via conduit 101, but less than the final discharge pressure 110. The baseline compressor receiving the compressed gases discharged from the booster compressor 105 may further compress the discharged gasses from the booster compressor to further raise the pressure to a pressure required for the discharged gases in conduit 110 of the gas handling system.
Embodiments of the compression system 100 may dynamically respond to changes in the environmental conditions present within the compression system 100 at any point during the operation thereof. As described above, embodiments of the compression system 100 may enter one or more different operating modes when variables defining the environmental conditions shift outside of the values set or range of values set as the baseline conditions. This dynamic response to changes in environmental conditions of the compression system 100 may occur by both selectively activating a second or subsequent operating mode as well as the subsequent return to the first operating mode when baseline conditions are met again.
Using the temperature example above, embodiments of LNG or LPG systems may include a re-liquefaction system which may activate and deactivate as it is needed. The activation and deactivation of the re-liquefaction system at one section of the LNG or LPG system may actually cause a rise and fall in environmental temperature of the gases entering compression system 100 through conduit 101. In some embodiments of an LNG or LPG system, activation of a re-liquefaction system may cause a rise in temperature of the gases entering the compression system 100 and the rise in temperatures may exceed the baseline conditions of the first operating mode. In response to the environmental conditions containing a temperature above the range of acceptable baseline temperatures, embodiments of the system 100 may dynamically activate a second operating mode to assist the compression system. The second operation mode may utilize both the booster compressor 105 and the baseline compressor 109 together in tandem to achieve a requisite discharge pressure in conduit 110 of the gas handling system incorporating compression system 100.
Subsequently, the LNG, LPG or other gas handling system may deactivate its re-liquefaction system connected to the downstream compression system. The deactivation of the re-liquefaction system may cause the temperature of the gases reaching the compression system 100 located downstream from the reliquefaction system to decrease back to within the baseline conditions. In response to the return of the gas temperature being within an acceptable range of the preset or pre-programmed baseline conditions, the compression system 100 may cease operating in the second operating mode and return to the first operating mode which may utilize the booster compressor bypass 103 to circumvent the unneeded booster compressor 105.
Embodiments of the compression system 100 may vary depending upon the equipment employed as part of the compression system. For example, a system 100 may include varying number of valves 124, 125, 126, 128, switches or gates 121, 123 and heat exchangers or intercoolers 111, 112. The type, configuration, location, and/or number of valves, switches, gates, heat exchangers or intercoolers integrated into the compression system 100 may depend on the purpose of the LNG, LPG or other gas handling systems that the embodiments of the compression system 100 are connected with. Moreover, the size, stages and energy consumption of the booster compressor 105 or baseline compressor 109 may vary and thus the amount of compressors needed, and the amount of cooling provided by the plurality of heat exchangers or intercoolers to these compressors 105, 109 may also vary as needed to maintain proper operating conditions or selected operating modes.
In further embodiments, an operating mode may include the operation of the booster compressor 105 alone, while the baseline compressor(s) may be turned off. For example, under circumstances where the environmental conditions inside the compression system may cause this operating mode to activate, gases arriving to the system 100 via conduit 101 may travel to the booster compressor 105, instead of utilizing the booster compressor bypass 103 used in the first or other operating mode. As the gases enter the booster compressor 105, the gases may be compressed to a pressure suitable for discharge at a target level of compression producing a compressed gas in conduit 110. In such an embodiment wherein the gases bypass the low duty baseline compressor 109, the gases may exit the booster compressor 105 via conduit 107, and bypass the baseline compressor(s) via a baseline compressor bypass configured to bypass the baseline compressor 109 (which may be turned off) and reach an outlet of the compression system discharging compressed gas 110.
In an alternative embodiment of a compression system 200, as shown in Fig. lb, a compression system 200 may further include a recycling loop 201 which may be connected to an inlet and a discharge of the booster compressor 105. In some embodiments of compression system 200, a portion of the gas entering the compression system 200 via conduit 101 may enter the booster compressor 105 instead of the bypass 103 at a first junction 102. In an effort to limit the effects of the booster compression loop when the first operating mode is active, the compressed gas exiting the discharge of the booster compressor 105 may be diverted into the recycle loop 201 instead of continuing along to conduit 107. As the gas, such as an intermediate compressed gas exits the discharge of the booster compressor, the recycling loop 201 may transfer the gas exiting the discharge of the booster compressor back to an inlet of the booster compressor.
As shown in the exemplary embodiment of FIG. 1b , the gases entering via conduit 101 may be directed to either enter the booster compressor 105 or the booster compressor bypass 103. As a portion of the gases enter the booster compressor 105, the discharged gases may be prevented from accessing the conduit 107 by a control valve, such as the process control valve 124 depicted in the figure. Because the compressed gases cannot pass beyond the control valve 124, the gas may be forced into the recycling loop 201 which cycles the intermediate compressed gas back to the booster compressor 105. As the conduit transporting the gases through the booster compressor becomes pressurized, additional gas may be unable to enter the booster compressor 105 or recycling loop 201 and therefore the gases entering the compression system 200 via conduit 101 may be forced through the bypass 103 when system 200 is functioning in the first operating mode.
The bypass 103 may also comprise a control valve 125 in some embodiments. When operating in the first operating mode under baseline conditions, this control valve 125 may remain open, allowing for the gasses to pass through the bypass 103 into the second conduit 107 and further into the inlet of the baseline compressor 109. However, in an embodiment of the compression system 200, wherein the operating mode may have switched from a first operating mode to a second operating mode, the control valve 125 present in the bypass 103 may close. Likewise, as control valve 125 closes upon changing to the second operating mode, the control valves 126 and 124, present in the booster compressor 105 loop, may open. In this embodiment, when the second operating mode is initiated, control valve 126 will open, control valve 124 will open, then control valve 125 will close and direct the gas to the booster compressor 105. The control valve 125 may partially or fully close to limit or prevent the gas leaving booster compressor 105 from returning to the inlet of booster compressor 105. Thus, the gasses entering the compression system 200 may be directed through the alternative route comprising the booster compressor 105 discharging into the inlet or suction line of baseline compressor 109 via conduit 107.
As the gas that was previously trapped in the recycling loop 201 discharges from the booster compressor 105, the gas may now exit through the control valve 124 that opened when the second operating mode activated. Instead of being caught in the recycling loop 201, the gases may now enter conduit 107 under the desired intermediate pressure provided by the booster compressor 105 and may be properly pressurized by the baseline compressor to the compressed discharge pressure in conduit 110. Furthermore, embodiments of the compression system 200 may further comprise one or more valves or gates, such as check valve 121 and 123, to prevent or hinder gas in conduit 107 from flowing backwards in the system. A control valve, such as process control valve 124, may be placed proximate, next to, or otherwise near check valve 123 to allow for the booster compressor 105 to be isolated and started without affecting the system 200. As shown in FIG. 1a and 1b . the one way check valve 121 may prevent the gases travelling from the bypass conduit 103 to the conduit 107 from travelling backwards into the bypass conduit. Likewise, check valve 123 may prevent gases exiting the booster compressor into conduit 107 from flowing back into the booster compressor loop or the recycling loop 201.
In the exemplary embodiments of the compression systems described herein and pictured in FIGS. 1a, 1b , 2, and 3, the booster compressor 105 and the baseline compressor 109 may be depicted as two or more physically separate compressor units. However, in alternative embodiments, the booster compressor 105 and the baseline compressor 109 may be a single compressor unit having multiple stages of compression, including a booster compressor section and a baseline compressor section. Similar to the systems described above, the single, integrated compressor unit may operate in multiple stages depending on the environmental conditions of the compression system and be further programmed to have a plurality of selectable operating modes, similar to the previous systems discussed. Likewise, embodiments of the integrated compression unit may also contain an open bypass when operating if the first operation mode which may prevent gas from entering the booster stage of the integrated compressor, as well as a recycling loop for the booster stage in some embodiments. Moreover, much like the embodiments described above, the integrated compressor unit may dynamically switch, engage or activate the programmed operating modes to engage or disengage the booster compression stages of the integrated compressor based on the environmental conditions and the pre-set baseline conditions or ranges of conditions.
Embodiments of the compression system 100, 200 are not limited to systems having only a single booster compressor 105 and a single baseline compressor 109. In some embodiments of compression systems, there may be a plurality of baseline or booster compressors employed in the system or a integrated baseline or booster compressor having a plurality of stages. As depicted in the embodiment of compression system 300, the baseline compressor may comprise one or several stages of compression. As shown by the exemplary embodiment of FIG. 2, the baseline compressor can be configured with a preset number of stages needed to reach the discharge in conduit 110 with the desired pressure.
In some embodiments, a plurality of baseline compressors 109, 309, 311, 313 may be used for the purposes of decreasing the size of the compressors or increasing energy efficiency over a system employing a fewer number of larger or more powerful compressors. In alternative embodiments, the system may employ multiple baseline compressors, where fewer compressors may not be feasible or practical. The number of baseline compressors or number of stages a baseline compressor may have in the system 300 may vary depending on the requirements and the uses of the LNG,LPG or other gas system integrating the compression system 300.
In alternative embodiments of the compression system, a plurality of baseline compressors 109, 309, 311, 313 are not limited to only being placed in series with one another to increase the overall pressurizing capabilities or efficiency of the compression system. In some alternative embodiments, a plurality of one or more baseline compressors 109, 309, 311, 313 may be placed in parallel with a second plurality of baseline compressors 408, 409, 411, 413.
As depicted in FIG. 3, a gas entering via conduit 107 may either enter the first plurality of baseline compressors 109, 309, 311, 313 and/or the second plurality of parallel baseline compressors 408, 409, 411, 413 via conduit 407. The gas entering the first plurality of baseline compressors 109, 309, 311, 313 and second plurality of baseline compressors 408, 409, 411, 413 may be compressed by one or more of the compressors until the pressure of the gas entering the second plurality of baseline compressors is discharged at the desired target pressure at either the first discharge in conduit 110 or the second discharge in conduit 410. As depicted in the exemplary embodiment, the compressed gases in conduit 110 and conduit 410 may combine to form a single stream of gases in conduit 420 having a pressure at the requisite pressure desired by the user and the gas system integrating or utilizing the compression system 400. These combined gases in conduits 110, 410 that flow into conduit 420 may then be transported to the next downstream step of the LPG, LNG or other gas system.
As the embodiments of the compression system integrated into the LNG, LPG or other gas systems becomes more complex or includes additional equipment and arrangements, additional operation modes may be utilized. For example, the first operating mode under baseline conditions in the compression system 400 may not utilize both the first plurality of baseline compressors 109, 309, 311, 313 and the second plurality of baseline compressors 408, 409, 411, 413 in some embodiments. Instead, operating modes may select one plurality of baseline compressors over the other, or the system may dynamically increase the number of active compressors in a set of each series of compressors as needed to compensate for changes in environmental conditions and compression work load.
In alternative embodiments of the compression system 400, not all of the compressor may be utilized at all times. In one instance, the first operating mode may only employ the first plurality of baseline compressors 109, 309, 311, 313. In the second operating mode, the system 400 may initiate the second plurality of baseline compressors when the environmental conditions of the system 400 reach a preset or preprogrammed value or within a range of values or parameters defining one or more environmental conditions. Subsequently, in some embodiments, a third operating mode may be employed when a predetermined set of environmental condition or variable values may be met, wherein the booster compressor, the first plurality of compressors 109, 309, 311, 313 and the second plurality of booster compressors 408, 409, 411, 413 alone, or in combination of one another may be activated.
In yet another embodiment, a fourth operating mode may be activated under a different set of conditions that may not arise to activate the first, second or third operating mode. For example, in this alternative embodiment, when the fourth operating mode is activated, the booster compressor may be activated along with the first plurality of baseline compressors. Alternatively in other embodiments, the operating mode may activate the baseline compressor and the second plurality of baseline compressors. Moreover, in additional embodiments of the compressor systems discussed above, the compressor system 500 may include a plurality of one or more booster compressors 105, 505 as shown in FIG. 5. The booster compressors may be used simultaneously depending on the operating mode activated, or the number of booster compressors engaged may increase or decrease depending on the operating mode selected by the user or as a result of the environmental conditions.
In addition to using the compressors in different operating modes, when there are compressors arranged in parallel, such as shown in FIG. 5, the plurality of one or more baseline compressor or the plurality of booster compressors 105, 505 may be used to provide back-up in case one or more compressors fail, is out of service for maintenance or otherwise not available. In some embodiments, the booster or baseline compressors may also be used alternately to balance the number of operating hours for each of the compressors in a particular operating mode.
As shown in FIG. 5, some embodiments of system 500 may include a heat exchanger 511, a recycling loop 501 and a valve or gate 523 connected via a conduit to the baseline compressor 501. The components of the parallel booster compressor 501 pathway may operate in the same or similar manner booster compressor 105, heat exchanger 111, valve or gate 123 and recycling loop 201. For example, whereas the heat exchanger 11 receives compressed gas from booster compressor 105, which enters the recycling loop 201 unless the gate 123 is opened, the gas entering booster compressor 505 may pass through heat exchanger 511 and return back to the booster compressor 505 via recycling loop 501 unless the valve or gate 523 is in the open state.
Referring now to FIGS. 1a -5, embodiments of methods for compressing a gas using the embodiments of the systems described above may include the steps of providing one or more booster compressors, a booster compressor bypass and one or more baseline compressors. The embodiments of methods may include the step of receiving by a conduit a stream of gas, such as an uncompressed gas or compressed gas into a gas compression system. In some methods, a step of measuring the environmental conditions within the conduit may be performed, for example through the use of sensors placed within the conduit. As previously described above, the gas compression system may have a pre-programmed value or range of values. Upon measuring the environmental conditions present in the conduit, the sensors may transmit environmental condition data to a computing system comparing the collected environmental conditions with the pre-programmed or pre-set environmental conditions.
In some embodiments of the method, after collecting and comparing the data describing the environmental conditions of the gas compression system, in some methods the gas compression system or a computing system connected thereto may further perform the step of selecting an preset or programmable operating mode.
The step of selecting the operating mode may include selecting an operating mode from a plurality of operating modes. In some embodiments the step of selecting an operating mode may be performed automatically based on the values or range of values defining the operating conditions and the environmental condition within the compression system itself. In alternative embodiments, the step of selecting the operating mode may be performed manually by the user of the compression system. For example a user may be selecting the operating mode at a remote or network accessible computing system electronically or remotely connected to the compression system.
In an example of an exemplary embodiment, the step of selecting an operating mode may be made by selecting a first operating mode or a second operating. In some embodiments, when the first operating mode is selected, the compression system may proceed by directing the stream of gas entering the system through a booster compressor bypass. The directing of the gas may be performed by one or more valves provided by the compression system and placed within the booster compressor bypass conduit and/or the booster compressor loop. Alternatively, the step of selecting a second operating mode may proceed by directing the stream of gas entering the compression system to the inlet of the booster compressor, wherein the booster compressor is active and operational, compressing the incoming gas to an intermediate compressed gas, discharging the gas at an intermediate pressure and transporting the intermediate compressed gases to the baseline compressor downstream from the booster compressor for further compression.
Embodiments of the methods for further compressing a gas to a desired final pressure may further include transporting the gas discharged from the booster compressor or the booster compressor bypass to one or more baseline compressors receiving the gas through the baseline compressor inlet. In some embodiments, the baseline compressor may proceed by compressing the gas received, pressurizing the gas to a predetermined or pre-requisite pressure and discharging the gas from one or more of the baseline compressors in the system at the pressure desired by the user of the system.
In an alternative embodiment comprising one or more baseline compressors running in parallel, receiving the gas from either the booster compressor or the booster compressor bypass, the method may further include the step of combining the pressurized gas from the each of the baseline compressors, after the step of discharging the gas from the baseline compressors at the pre-set, or pre-requisite pressure.
The following software simulation examples are provided for illustrative purposes. The simulations are intended to be non-limiting and are intended to further explain and assist in clarifying the benefits and energy savings are realized when one or more of the elements of the embodiments described above are employed:

TABLE 1

Single Compressor System

Operating

Conditions	1	2	3

Gas	Nitrogen-7.41	Nitrogen-7.41	Nitrogen-7.41
Composition	Methane-92.56	Methane-92.56	Methane-92.56
(mol %)	Ethane-0.03	Ethane-0.03	Ethane-0.03
Total	100	100	100
Molecular weight	16.93	16.93	16.93
Mass Flow (kg/hr)	6000	6000	6000
Inlet Pressure	1.06	1.06	1.06
(barA)
Inlet	20	−90	−110
Temperature
(° C.)
Discharge	17	17	17
Pressure (barA)
Coupling Power	1246	1355	1571
(kW)

TABLE 2

Booster Compressor System

Operating

Conditions	1	2	3

Configuration	Booster	Baseline	Baseline only	Baseline only
			Booster-Off	Booster-Off
Gas	Nitrogen-7.41	Nitrogen-7.41	Nitrogen-7.41	Nitrogen-7.41
Composition	Methane-92.56	Methane-92.56	Methane-92.56	Methane-92.56
(mol %)	Ethane-0.03	Ethane-0.03	Ethane-0.03	Ethane-0.03
Total	100	100	100	100
Molecular	16.93	16.93	16.93	16.93
weight
Mass Flow	6000	6000	6000	6000
(kg/hr)
Inlet Pressure	1.06	2.2	1.06	1.06
(barA)
Inlet	20	46	−90	−110
Temperature
(° C.)
Discharge	2.35	17	17	17
Pressure (barA)
Coupling	319	1056	1070	1053
Power (kW)

Total Coupling	1375	1070	1053
Power (kW)
Coupling Power	+128.7 kW	−285 kW	−464 kW
Differential
(Table 2-Table 1)

As demonstrated by the simulation data presented above in Tables 1 and 2, the booster compressor system offers a significant energy savings over the single compressor system simulated in Table 1. By introducing a dynamically activated and deactivated booster compressor that may only be needed to operate under more stressful conditions, the baseline compressors of the booster compressor system simulated in Table 2 may be smaller, more energy efficient and include a lower number of stages that the compressors needed for the single compressor system provided in the simulation of Table 1. The compressors in the single stage compressor system may be larger, more complex, have an increased number of compression stages and thus require more energy to operate because the single compressor system described in the simulation of Table 1 should be designed in a manner that allows for the single compressor to handle not only colder compressed gases at lower temperatures (such as −90° C. and −110° C.), but also warmer gases having an inlet temperature of 20° C. as shown in the example. With a wider range of operation, the single compressor system may require a higher overall coupling power, whereas booster compressor system having the results of Table 2 may rely on the booster compressor for the compression of warmer gases (such as the 20° C. example) to an intermediate pressure followed by final compression with the baseline compressor.
Although temperature conditions that selectively implement an operating mode that utilizes both the booster compressor and the baseline may see an increase of coupling power to provide an adequate amount of overall compression in some embodiments, as shown in Table 2, under an operating mode that does not require the implementation of the booster compressor, a significant savings can be realized in the amount of coupling power used. As shown in the table 2 above, by being able to use a more energy efficient baseline compressor, the booster compressor system of table 2 was able to reduce coupling power for handling non-booster operating modes by 285 kW and 464 kW at temperatures of −90° C. and −110° C. respectively. A reduction in coupling power of the baseline compressor between 18 to 35%. However, depending of the configuration of the particular embodiments as described above, it is anticipated that savings in coupling power of the compressors may be a reduction of 35-50%, 50-65%, 65-85%, or 85-100%.
While this disclosure has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the present disclosure as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, as required by the following claims. The claims provide the scope of the coverage of the invention and should not be limited to the specific examples provided herein.

Claims

1. A gas compression system comprising:

a booster compressor;

a booster compressor bypass;

a conduit connected to the booster compressor and the booster compressor bypass;

a plurality of baseline compressors connected to the conduit, the plurality of baseline compressors connected to one in another in series;

wherein a stream of gas is either directed through the booster compressor or the booster compressor bypass to the plurality of baseline compressors, based on a measurement of an environmental condition present in the gas compression system.

2. The gas compression system of claim 1, wherein the conduit further comprises a sensor configured to measure the environmental conditions within the conduit and transmits data of the environmental condition to a computing system.

3. The gas compression system of claim 2, wherein the sensor measures an environmental condition selected from the group consisting of a volume of gas, temperature of gas and the temperature of the gas compression system.

4. The gas compression system of claim 1, further comprising a recycling loop connected to an inlet and a discharge of the booster compressor.

5. The gas compression system of claim 4, wherein the recycling loop returns an intermediate compressed gas that exits the discharge back to the inlet of the booster compressor.

6. The gas compression system of claim 1, wherein the booster compressor enters a low power state when the gas compression system selectively directs the flow of gas to the booster compressor bypass.

7. The gas compression system of claim 1, comprising an integrated compressor unit incorporating the booster compressor, the plurality of baseline compressors, and the booster compressor bypass into a single compressor unit having multiple stages, wherein the booster compressor is a booster stage of an integrated compressor unit, and the booster compressor bypass is a bypass that prevents gas from entering the booster stage.