Low-emission compression station without a dedicated power generation island

Abstract

A low emission compression station is disclosed. The low emission compression station includes one or more compressors, each compressor coupled to an electric machine, the electric machines coupled to at least one mechanically driven gas turbine and / or at least one fuel cell, the electric machines and / or the mechanically driven gas turbine and / or the fuel cell sized to meet both the process demands and the electrical load and controlled by a monitoring system (EMS / PMS). When an electric machine is coupled to a mechanically driven gas turbine, a hybrid gas turbine can be used.

Description

Technical Field

[0001] The present disclosure relates to improvements in compressor stations, typically used in pipelines, that can improve efficiency by reducing carbon emissions. In particular, but not exclusively, the present disclosure relates to a configuration and size that can achieve very high reliability without the need for an additional power generation island dedicated to the compressor station, and one or more compressors coupled to an electromechanical machine powered by a fuel cell or mechanically driven by a gas turbine system.

Background Art

[0002] It is well known that natural gas is extracted from deep underground rock formations and needs to be transported to end users. Generally, pipeline transportation is used to transport gas when possible or economically appropriate. To compensate for pressure losses during transportation, pipelines require compressor stations configured along the pipeline at regular intervals. The compressors of these compressor stations must operate very reliably with low maintenance requirements. As a result, compressors for pipeline applications, as well as other rotating equipment for applications in the oil and gas industry, are often driven by gas turbines.

[0003] In addition, since pipelines extend over long distances and compressor stations can be located in remote locations, in the absence of a power distribution grid or where the power distribution grid is available but unreliable, compressor stations generally include a dedicated power generation island for supplying power to auxiliary systems, enabling the compressor station to operate separately from the power distribution grid or to operate even when the power distribution grid is not operating. In particular, the power generation island includes a gas turbine and / or a reciprocating engine generator drive device that operates exclusively to supply power to the auxiliary system of the compressor station.

[0004] The power capacity of a gas turbine depends on ambient conditions, namely temperature and other specific factors. The power capacity of a gas turbine is inversely proportional to the ambient temperature. To prevent power loss (in the case of a gas turbine trip) that could cause a compression station shutdown, power generation islands are generally designed to be fully redundant; that is, the power generation island includes at least two gas turbine trains, a first and a second, each sized to independently provide the power required by the compression station's auxiliary systems. If the drivability of the first gas turbine train is compromised, it can be easily replenished by the second gas turbine train, or even replaced by it. Typically, such a result is achieved by operating both gas turbine trains at 50% load, allowing for easy relay of full rotational reserve capacity when needed.

[0005] A gas turbine train operating at 50% load operates under suboptimal conditions, and this configuration with two fully redundant gas turbine trains has the disadvantage of accelerating turbine wear. In addition, under normal operation, the efficiency of two fully redundant gas turbine trains is also low, and the highest efficiency is always obtained when the endothermic machine is operating at 100% load.

[0006] Furthermore, for safety reasons, power generation islands for compression stations must generally be built a sufficient distance from the compression station itself. This involves additional costs for the associated infrastructure with turbomachinery of the same scale, along with the additional costs for the high-voltage electrical network and associated substations.

[0007] The market includes so-called hybrid mechanically driven gas turbines, in which an electromachine connected to the power grid is combined with a gas turbine to drive one or more loads such as compressors or pumps. This electromachine can operate as a motor that absorbs power from the power grid to drive (or contribute to driving) the load, or as a generator that supplies surplus power to the power grid.

[0008] In particular, electromechanical systems can be used to supplement the mechanical force to the load, to maintain a constant overall mechanical force on the load shaft when the power availability of the turbine decreases, and / or to increase the total mechanical force used to drive the load. This function of the electromechanical system is called helper mode. In helper mode, both the gas turbine and the electromechanical system supply power to the load. In this case, the electromechanical system absorbs energy from the power grid and operates as a motor, while the gas turbine also supplies energy to the load. Therefore, the power received by the load is the sum of the power generated by the gas turbine and the power generated by the electromechanical system.

[0009] When surplus mechanical power is available from the turbine, for example, when the ambient temperature drops below the design temperature and increases accordingly, or when the mechanical load required by the compressor decreases, the surplus mechanical power generated by the gas turbine is converted into electricity using an electromechanical unit as a generator. In generator mode, the gas turbine supplies energy to the load, and the electromechanical unit supplies surplus energy to the power grid. In this operating mode, the power generated by the gas turbine is effectively divided into supplying energy to the load and introducing energy into the power grid.

[0010] The electromechanical unit can also be used to provide all the mechanical power needed for the load when the turbine is not operating. This function of the electromechanical unit is called the maximum electrical mode. In the maximum electrical mode, the gas turbine may be disconnected, or even shut down, and therefore not function at all, while the electromechanical unit drives the load and thus absorbs energy from the power grid, thus the electromechanical unit acts as a motor. In this configuration, a clutch may be used to convert the train system into a zero-emission operating mode.

[0011] Finally, in the fourth operating mode, called the maximum power generation mode, the speed is kept at the minimum operating speed, so that loads such as compressors or pumps absorb the minimum torque, electromechanical units act as generators, and the gas turbine generates power. This operating mode is typically activated whenever there is a power absorption peak required by the power grid, and therefore the power generated by the turbine must be converted into electrical energy and injected into the power grid. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] However, currently, hybrid gas turbine systems are always implemented in configurations that are constantly connected to the power grid in order to achieve a high level of reliability.

[0013] Therefore, improved compression stations that can achieve a high level of reliability without requiring connection to power generation stations and / or distribution grids would be welcome in this field, as they would significantly reduce emissions and simultaneously lower both CAPEX and OPEX. More specifically, compression stations that include hybrid gas turbines, offering improved flexibility and reliability and capable of operating in fully isolated mode, would be welcome.

[0014] Within the framework of this invention, the term "bonding" is used to refer to mechanical, electrical, or magnetic connections, depending on the context.

[0015] In one embodiment, the subject matter disclosed herein relates to a low-emission compression station comprising a plurality of compressors, each compressor being coupled to an electromechanical unit, the electromechanical unit being coupled to at least one fuel cell and / or at least one mechanically driven gas turbine, along with associated electromechanical units including possible integration with a battery pack, the fuel cell and / or mechanically driven gas turbine being sized for rotational backup electrical and / or mechanical load management, and controlled / monitored by an electrical monitoring system that interfaces with digital optimizers of at least several compressor station components to ensure a complete uninterrupted power supply to the compressor station and eliminate the need for a power generation island.

[0016] In another embodiment, the subject matter disclosed herein relates to a low-emission compression station in which the compression station is integrated with components including a renewable source (e.g., solar panels or wind turbines), a gas storage, an auxiliary energy source such as a fuel cell, and an energy storage device.

[0017] In yet another embodiment, the subject disclosed herein relates to a low-emission compression station in which an electrical monitoring system is configured to manage all energy sources (batteries, emergency, and renewable sources) to align with one another.

[0018] In yet another embodiment, the subject matter disclosed herein relates to a low-emission compression station in which an electrical monitoring system is configured to manage load limits.

[0019] In another embodiment, the subject matter disclosed herein relates to a low-emission compression station that reduces the required CAPEX due to the absence of a dedicated power plant and reduces OPEX due to a smaller number of units subject to maintenance.

[0020] In another embodiment, the subject matter disclosed herein relates to a low-emission compression station that reduces the required footprint in the absence of a dedicated power plant, where the delta footprint can be used for the installation of renewable sources such as solar panels / wind turbines. Furthermore, in the case of offshore applications, the absence of a dedicated power island is beneficial not only in terms of footprint but also in terms of weight savings for such power generation services. [Brief explanation of the drawing]

[0021] Many of the disclosed embodiments of the present invention and their associated advantages will be better understood by referring to the following embodiments for carrying out the invention, and a complete understanding will be easily obtained, when considered in relation to the accompanying drawings. [Figure 1] Figure 1 is a schematic diagram of a low-emission compression station according to a first embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic diagram of a low-emission compression station according to a second embodiment of the present disclosure. [Figure 3] Figure 3 is a schematic diagram of a low-emission compression station according to a third embodiment of the present disclosure. [Figure 4] Figure 4 is a schematic diagram of a low-emission compression station according to a fourth embodiment of the present disclosure. [Modes for carrying out the invention]

[0022] Referring to Figure 1, a low-emission compression station according to a first embodiment of the present disclosure includes a mechanically driven hybrid gas turbine configuration (referenced by reference numeral 10) in such a configuration and in a particular method of turbomechanical sizing to eliminate the need for an additional power generation island dedicated to the compressor station.

[0023] In particular, the hybrid gas turbine 10 and associated electrical machinery include the possibility of integration with a battery pack 11, or another energy storage system such as, for example, a battery energy storage system (BESS), liquid air energy storage (LAES), hydrogen storage, etc. One or more other components include a renewable energy system 12, oil and gas compression station facilities 13, a power grid island 14, and an emergency power generation island 15, which are sized and controlled by an electrical monitoring system 16 to ensure a complete uninterrupted power supply to the compression station. This configuration is particularly suitable for pipelines, but is not limited to pipelines, and each compression station can be equipped with two or three gas turbines with complete redundancy for availability purposes.

[0024] The solution according to the present disclosure reduces the CAPEX of the compression station. In fact, typically, according to the prior art, a power generation island dedicated to a compressor station is composed of two generators and a gas turbine operating at a reduced load. In particular, considering that 50% of the load is required to relay the full rotational reserve capacity, the estimated dedicated power generation island includes two gas turbines (e.g., gas turbine model Nova LT (trademark) 12 (produced by Baker and Hughes), etc.) and all related infrastructure (civil engineering, piping, etc.) and installations. On the other hand, the hybrid implementation form only includes hybrid machine-driven gas turbines, and each hybrid machine-driven gas turbine is sized to fit both process requirements and electrical loads.

[0025] The proposed solution using a hybrid machine-driven gas turbine appropriately sized for rotational reserve load management also means higher efficiency since the hybrid machine-driven gas turbines operate at a higher load. In addition, by leveraging renewable power generation, the efficiency of the station can be increased and thus can be used to decarbonize the compression. This option reduces CAPEX while leveraging compression electrification.

[0026] In particular, when a single hybrid mechanically driven gas turbine is used, according to configurations not part of the present invention, the sizing of the gas turbine must take into consideration that the power generation portion of the gas turbine must have the capacity to cover 100% of the utility load. In such cases, backup power should be provided by an emergency battery pack or an emergency diesel compressor.

[0027] According to this disclosure, when two fully redundant hybrid mechanically driven gas turbines are used, the main train covers the process needs, with available surplus power covering a portion of the electrical load (typically 50%), while the standby train operates in pure power generation mode to cover only the remaining 50% of the load. One of the two gas turbines is designed to provide the maximum electrical load and ensures full power generation to the compressor station by the concept of a rotating spare, guaranteeing an uninterrupted power grid supply. If a battery pack is employed for the rotating spare, the standby unit starts when the main unit trips to provide both the process load and the power generation load.

[0028] In the case of multiple hybrid mechanically driven gas turbines, the concept is similar to the previous case with two gas turbines, but a greater degree of freedom for load distribution is available. In addition, in this case, the third / fourth train can also operate in maximum electric mode if power is available.

[0029] At peak ambient temperatures during the day, the power loss of the main compressor train can be offset by unbalancing the electrical load sharing between the two gas turbines from a typical 50%-50% to 0-100%, i.e., 100% for the gas turbine operating in pure power generation mode and 0% or even a negative value for the main compressor train, in which case the main compressor train absorbs power (the generator absorbs power in helper mode configuration and operates as a motor). If the second gas turbine operating in pure power generation mode does not have enough power to supply the main compressor train and plant consumption, the battery pack and oil and gas compression emergency systems may be required to "assist" the main compressor train. Load limiting can also be used for this purpose.

[0030] Figure 2 shows a low-emission compression station according to a second embodiment of the present disclosure. This system configuration includes a hybrid mechanically driven gas turbine 20 and associated electromechanical equipment including one or more renewable energy systems 22, oil and gas compression station equipment 23, an optional power grid island 24, and / or ultimately an emergency power island 25, which are sized and controlled / monitored by an electrical monitoring system 26 to ensure a complete uninterrupted power supply to the compressor station. In this embodiment, a hydrogen storage system 21 is present, comprising an electrolytic cell 211 for producing hydrogen, a compressor 212 and a storage tank 213, and a connection to a pipeline 214, the hydrogen of which can optionally be blended with natural gas. Hydrogen from the storage tank 213 can be sent to the hybrid mechanically driven gas turbine 20 as a blend containing up to 100% natural gas, optionally. Hydrogen sent to the pipeline via the connection 214 can also be used together with the natural gas in the pipeline to operate the hybrid mechanically driven gas turbine 20. Combustion of a blend consisting of natural gas and hydrogen also contributes to reducing CO2 emissions. The hydrogen, which is supplied to the pipeline via connection 214, can also be used as the sole fuel source to operate the hybrid mechanically driven gas turbine 20. As a result, the combustion of hydrogen minimizes CO2 emissions.

[0031] Figure 3 shows a low-emission compression station according to a third embodiment of the present disclosure. The system configuration includes a hybrid mechanically driven gas turbine 30 connected to a fuel cell 37 (such as a solid oxide fuel cell), and associated electromechanical equipment including one or more renewable energy systems 32, oil and gas compression station equipment 33, an optional power grid island 34, and / or ultimately an emergency power island 35, which are sized and controlled / monitored by an electrical monitoring system 36 to ensure a complete uninterrupted power supply to the compressor station. In addition, this embodiment includes a hydrogen storage system 31 having the same components as those already shown with reference to Figure 2, namely, an electrolytic cell 311, a compressor 312, a storage tank 313, and a connection to a pipeline 314 from which hydrogen can be blended with natural gas. The power island 35 and the fuel cell 37 are supplied with hydrogen from the hydrogen storage tank 313 and / or with hydrogen, natural gas, or a mixture of hydrogen and natural gas from the pipeline 314. Combustion of a blend consisting of hydrogen and natural gas contributes to reducing CO2 production, while combustion of hydrogen minimizes CO2 production when hydrogen is used as the sole fuel source to operate the hybrid mechanically driven gas turbine 30 and fuel cell 37.

[0032] Figure 4 shows a low-emission compression station according to a fourth embodiment of the present disclosure. This system configuration includes a compressor 40 with respective electromechanisms electrically connected to a fuel cell 47 (such as a solid oxide fuel cell). This system configuration also includes associated electromechanisms including one or more renewable energy systems 42, oil and gas compression station equipment 43, an optional power grid island 44, and / or ultimately an emergency power island 45, which are sized and controlled / monitored by an electrical monitoring system 46 to ensure a complete uninterrupted power supply to the compressor station. In addition, this embodiment includes a hydrogen storage system 41 having the same components as those already shown with reference to Figure 2, namely, an electrolytic cell 411, a compressor 412, a storage tank 413, and a connection to a pipeline 414 from which hydrogen can be blended with natural gas. Furthermore, according to this embodiment, the fuel cell 47 is supplied with hydrogen from the hydrogen storage tank 413 and / or hydrogen, natural gas, or a mixture of hydrogen and natural gas from the pipeline 414, thus reducing or minimizing CO2 production.

[0033] While the present invention has been described in relation to various specific embodiments, it will be apparent to those skilled in the art that many modifications, changes, and omissions are possible without departing from the spirit and scope of the claims. In addition, unless otherwise specified herein, the order or arrangement of any process or method step may be changed or rearranged according to alternative embodiments.

[0034] Detailed references are made to embodiments of this disclosure, and one or more of these examples are illustrated in the drawings. Each example is provided for illustrative purposes only and is not limiting to the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from the scope or spirit of the disclosure. Throughout this specification, references to “one embodiment,” “a certain embodiment,” or “some embodiments” mean that a particular feature, structure, or characteristic described in relation to a particular embodiment is included in at least one embodiment of the subject matter disclosed. Thus, where the phrases “in one embodiment,” “a certain embodiment,” or “some embodiments” appear in various places throughout this specification, they do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics can be combined in any preferred manner in one or more embodiments.

[0035] When presenting elements of various embodiments, the articles "a," "an," "the," and "said" are intended to indicate that there is one or more of the elements. The terms "comprising," "including," and "having" are intended to be non-exclusive and mean that additional elements other than those listed may exist.

Claims

1. A low-emission compression station comprising one or more compressors, each compressor coupled to an electromechanical unit, the electromechanical unit coupled to at least two hybrid mechanically driven gas turbines, the electromechanical unit and / or the hybrid mechanically driven gas turbines being sized to meet both the process requirements and electrical load of the compression station, and controlled by an EMS / PMS. The monitoring system operates each of the at least two hybrid mechanically driven gas turbines in one of a plurality of operating modes, including an operating mode that provides both process load and electrical load, and a pure power generation mode, and controls the operating mode and the proportion of electrical load distribution of each of the hybrid mechanically driven gas turbines according to the situation. Low-emission compression station.

2. The low-emission compression station according to claim 1, wherein the monitoring system is interfaced with a digital optimizer which is a component of the compression station.

3. The low-emission compression station according to claim 1, wherein the monitoring system includes a digital optimizer.

4. The low-emission compression station according to claim 1, wherein the compression station is integrated with an energy storage device.

5. The low-emission compression station according to claim 1, wherein the compression station is integrated with a battery pack.

6. The low-emission compression station according to claim 1, wherein the compression station is integrated with an auxiliary energy source.

7. The low-emission compression station according to claim 6, wherein the auxiliary energy source includes a renewable energy source.

8. The low-emission compression station according to claim 1, wherein the monitoring system is configured to manage all energy sources integrated with the compression station for alignment with each other.

9. The low-emission compression station according to claim 1, wherein the monitoring system is configured to manage load limits.

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