Power plant controls renewable energy use in LNG trains

Abstract

A power plant is disclosed that controls renewable energy absorbed by a hybrid powertrain (2) for driving a load, in particular a compressor for liquefied natural gas (LNG), and analyzes the health of its components that drive the load, in particular a hybrid gas turbine system.

Description

[Technical Field]

[0001] The present disclosure relates to a power plant that is operated to maximize the use of renewable energy sources in a liquefied natural gas (LNG) plant to improve efficiency, reduce overall maintenance costs, and reduce pollution introduced into the atmosphere. [Background technology]

[0002] As is well known, natural gas is one of the most important energy sources currently available on the market. It is estimated that approximately 30% of the world's energy demand is met directly or indirectly by natural gas.

[0003] Natural gas is usually delivered in gas form by pipeline. However, over the past two decades, liquefied natural gas (LNG) plants have become much more important in the energy market. LNG is expected to play a very important role in the world's transition to cleaner (greener) energy sources. This is why LNG is being strongly promoted by national governments and several public and private institutions.

[0004] LNG is natural gas in liquid form. To liquefy natural gas, its temperature must be reduced to a cryogenic temperature of approximately -160°C. As a liquid, natural gas occupies a fraction of the volume it had when extracted (approximately 1 / 600th of its volume at atmospheric pressure), and therefore its transportation and storage costs prove much lower and more practical. LNG is also easier to transport over long distances. In this regard, natural gas is often extracted in areas where pipeline transportation is not possible.

[0005] To cool the natural gas, several compressors must be driven. As is well known, a compressor is a machine driven by a gas turbine that acts on the refrigerant gas to raise the pressure head of the fluid. Several different compressors are available, including centrifugal compressors and reciprocating compressors. Generally, an array of centrifugal compressors is driven.

[0006] The centrifugal compressor array in an LNG plant is usually driven by at least one gas turbine. In recent years, even as energy demands have increased, electric motor / generators operating on the same shaft as the gas turbine have been added. The combination of a gas turbine and an electric motor / generator is also called a hybrid gas turbine system, a hybrid gas turbine train, or a hybrid powertrain.

[0007] One problem with powertrains typically used in LNG plants, including hybrid powertrains, is that they emit pollutants, particularly due to the operation of the gas turbine. This problem is overcome by hybrid powertrains, particularly because the electric motor / generator can absorb energy from the mains to which it is connected or can introduce excess energy generated by the gas turbine into the mains, reducing the rate at which pollutants are produced per watt produced.

[0008] In fact, electric motor / generators are also called electric reversible machines because they can also operate as generators. Electric motor / generators are controlled by devices known as variable frequency drives (VFDs), devices designed to drive the electric motor / generator at any different operating conditions to maximize power transfer while driving a mechanical load (either a compressor or a gas turbine, for example, to start it).

[0009] The synergy between gas turbines and electric motors / generators has been exploited over the past few years to reduce pollutants released into the atmosphere.

[0010] For example, there are available systems that control hybrid powertrains installed in LNG plants by monitoring and adjusting operating variables. These systems can monitor the overall degradation of the system's performance over time. However, not all components of a hybrid powertrain deteriorate to the same extent. Available monitoring and control systems cannot control hybrid powertrains to maximize the lifespan of their constituent parts. Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, improved hybrid powertrains that can reduce pollution and reduce maintenance costs (and therefore CAPEX) would be welcome in the art.

[0012] The subject matter disclosed herein is a power plant operated by a method for controlling a hybrid powertrain, installed in an LNG plant or other type of plant as well, while driving a load such as, for example, but not limited to, a compressor, a pump, or any other machine, that uses one or more control signals received from equipment and components of the hybrid powertrain to enable control of the fuel supplied to the gas turbine and the power generated or converted by the electric motor / generator, and to maximize the power generated, maximize the life of the gas turbine, and minimize pollutant emissions.

[0013] The disclosed subject matter relates in some embodiments to a single shaft unit rigidly connected to an electric motor / generator, particularly intended for LNG production or similar high energy intensive processes, capable of using information and variables. This power plant operation can be performed using, but is not limited to, gas turbine diagnostics and physics-based models, dry low NOx, and other similar processes. x (DLN dry low NO x; Dry combustion (where pollutant reduction is achieved by the combustor itself without water or steam injection, hence wet reduction), electrical / motor health parameters such as partial discharge, variable frequency device health parameters for predicting gas turbine power management, solar / wind farm health parameters, etc. based on specific event-based actions related to optimizing availability and generation targets.

[0014] The subject matter disclosed herein is also directed to hybrid powertrains that, when using renewable energy sources, can reduce pollution by balancing the energy obtained from renewable resources, balancing the use of renewable resources with the energy generated by the gas turbine, and maximizing the RTE (round trip efficiency; this relates to the overall efficiency of the process of charging an energy storage device and recovering and reusing energy from the storage device) of the renewables as well as the reliability and availability of the train.

[0015] The disclosed solution aims to maximize the reliability of highly energy-intensive processes, such as LNG plants with hybrid powertrains, when using renewable sources, in order to make it possible to take as much electricity as possible coming from renewable energy while optimizing LNG production. The direct use of renewable energy production plants for LNG production reduces the use of renewable energy and turbine emission pollutants (CO2, NO2). x ) to optimize usage.

[0016] In one aspect, the subject matter disclosed herein is directed to a power plant operated by a method for controlling renewable energy absorbed by a hybrid powertrain for driving a load. The hybrid powertrain includes a gas turbine and an electric motor / generator as equipment, the electric motor / generator connected to a power plant and a renewable energy source. The method for operating the power plant provides detecting input parameters of each equipment before applying a first conditional statement to determine a joint membership function. The joint membership function can have two or more qualification states as outputs to check whether the equipment operates correctly. If the equipment operates correctly, a second conditional statement is applied to a renewable energy source (such as a photovoltaic plant, a wind power plant, or a concentrated solar power system), thereby determining a membership function for the renewable energy source. The membership function for the renewable energy source has two or more qualification states as outputs, such that if the qualification states do not operate correctly, a third conditional statement is implemented to the power plant to check whether the power plant operates correctly. If so, a change in load division between the gas turbine and the electric motor / generator is implemented.

[0017] If the renewable energy source operates in the correct manner, the power generated by the gas turbine and the energy absorbed by the renewable energy source are determined according to the objective function. Otherwise, if the checked equipment does not operate correctly, load sharing between the gas turbine and the electric motor / generator is implemented.

[0018] In another aspect, the subject matter disclosed herein relates to an equipment including a variable detection device connected to an electric motor / generator, a power plant, and a renewable energy source. In the detecting step, the detected initial state is the state of the electric motor / generator and the variable detection device. The first conditional statement also includes the substeps of associating a parametric membership function with each input parameter of the electric motor / generator, combining the parametric membership function of the electric motor / generator via a truth table to obtain a health index and then an equipment membership function, associating the parametric membership function with each input parameter of a variable frequency device, and combining the parametric membership function of the variable frequency device via a truth table to obtain a health index and then an equipment membership function. Finally, the membership functions of each piece of equipment are combined to obtain a combined membership function having two or more qualification states as an output.

[0019] In another aspect, it is disclosed herein that a joint membership function can estimate a first state of qualification, a second state of qualification, and a third state of qualification. If the joint membership function estimates the first state of qualification (Bad), the load on the gas turbine is increased and the electric motor / generator is shut off. If the joint membership function estimates the second state of qualification (Medium), the load division between the gas turbine and the electric motor / generator is changed. If the joint membership function estimates the third state of qualification (Good), a second conditional statement is applied to the renewable energy source.

[0020] A further aspect of the present disclosure is to provide a gas turbine with a load that is greater than or equal to a combustor transfer threshold Pmx Load and load margin Δ Load The objective function is to minimize the use of the gas turbine to handle potential load overloads so that the load remains above the sum of

[0021] In another aspect, it is disclosed herein that the input parameter is an analog electrical signal or a digital electrical signal.

[0022] In one aspect of the disclosure, an electric power plant includes a hybrid powertrain having a through shaft, a gas turbine mechanically connected to the shaft, an electric motor / generator mechanically connected to the shaft, and a variable frequency device connected to the electric motor / generator, the power plant, and a renewable energy source. The variable frequency device is operable to enable the electric motor / generator to convert energy from the power plant and the renewable energy source to drive a load or assist in the operation of the gas turbine. The power plant also includes a load mechanically connected to the shaft and a plant control unit for controlling the hybrid powertrain to maximize the used energy coming from the renewable energy source by maximizing the driving load of the electric motor / generator.

[0023] In one aspect of the present disclosure, the load includes one or more centrifugal compressors for cooling natural gas. [Brief explanation of the drawings]

[0024] A complete understanding of the disclosed embodiments of the present invention and many of the attendant advantages thereof will be readily obtained as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings. [Figure 1] FIG. 1 is a diagram illustrating a control system for a hybrid powertrain for controlling a load to maximize the use of renewable energy sources. [Figure 2] FIG. 2 is a schematic diagram of a plant hybrid powertrain connected to an energy source and a driven load. [Figure 3] FIG. 3 is a schematic diagram of the plant control unit. [Figure 4] FIG. 4 shows a flowchart of a method for controlling the use of renewable energy according to the first embodiment. [Figure 5]FIG. 5 is a diagram showing a flowchart of a first conditional statement of the method for controlling the use of renewable energy according to the first embodiment. [Figure 6] FIG. 6 shows a set of parameter signals processed by the method for controlling the use of renewable energy according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing a set of truth tables implemented in the method for controlling the use of renewable energy according to the first embodiment. [Figure 8] FIG. 8 is a diagram showing a flowchart of a second conditional statement of the method for controlling the use of renewable energy according to the first embodiment. [Figure 9] FIG. 9 is a diagram showing a flowchart of a third conditional statement of the method for controlling the use of renewable energy according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Liquefied natural gas is an important energy source. The extracted gas needs to be liquefied. For this purpose, several compressors are used. To drive the compressors, hybrid powertrains are used. These include a gas turbine and an electric motor / generator. The electric motor / generator is a machine that can be connected, among other things, to a renewable energy plant to convert the energy produced by such a plant and use this energy to drive the compressor, minimizing the use of the gas turbine to an appropriate level and thereby reducing the pollutants released into the environment.

[0026] According to one aspect, the present subject matter is directed to a method for controlling the use of renewable energy in an LNG train that can ensure reliable operation of the LNG plant / train and avoid adverse effects on train availability when renewable sources are used to partially or fully provide the required power.

[0027] LNG production, being an energy intensive process, can be seen as a renewable storage or energy accumulator, where every watt produced can be used for production, regardless of the moment (day, night, winter or summer) and the amount it is produced, without the need for or by minimizing physical storage, and therefore at a very high RTE.

[0028] Referring to Figure 1, one embodiment of an LNG refrigeration plant is shown and designated by the reference numeral 1. The LNG refrigeration plant 1 comprises a hybrid powertrain 2 and a load 3 connected to and driven by the hybrid powertrain 2. A power plant PG, which may be mains or any conventional power generation facility, and a general renewable energy source, designated by the reference PV, are both connected to the hybrid powertrain 2, as will be explained in more detail below.

[0029] With respect to renewable energy source PV, any energy plant or system capable of producing energy from renewable sources is intended, such as photovoltaic plants, wind energy plants, concentrated solar power systems, marine or wave energy plants, etc. In the following, photovoltaic plants are intended as renewable energy source PV, without limiting the scope of protection of the solutions described. In any case, other renewable energy production plants or combinations thereof may also be considered.

[0030] The hybrid powertrain 2 includes a gas turbine 21, an electric motor / generator 22, and a variable frequency device (VFD) 23 connected to the electric motor / generator 22 and to the power plant PG and the photovoltaic plant PV. The hybrid powertrain 2 also includes a shaft 24. The gas turbine 21 and the electric motor / generator 22 are connected to the same shaft 24.

[0031] Electric power for the load 3 may come from a gas turbine 21, a power plant PG, and / or a photovoltaic plant PV.

[0032] 1 comprises two compressors 31 and 32 for compressing liquefied natural gas in the embodiment considered. Compressors 31 and 32 are mechanically connected to shaft 24. However, in other embodiments, different loads, such as pumps, can be driven by hybrid powertrain 2 without departing from the scope of protection of the disclosed solution.

[0033] Additionally, in other embodiments, there is at least one compressor, or more than two compressors, depending on the requirements of the plant.

[0034] The gas turbine 21 may be of different types, such as, for example, a two-shaft gas turbine or a single-shaft gas turbine. In other embodiments, other types of gas turbines may be installed.

[0035] The electric motor / generator 22 is adapted to operate as a motor and thus convert electrical energy obtained from the power plant PG or the photovoltaic plant PV into mechanical energy to drive the load 3, or as a helper to supply additional energy to the energy supplied by the gas turbine 21 required by the load 3, or as a starter to operate the gas turbine 21. The electric motor / generator 22 can also operate as a generator and inject any surplus energy produced by the gas turbine 21, for example into the power plant PG or the mains.

[0036] The variable frequency device 23 is a motor drive device. Variable frequency devices 23 are typically used in electromechanical drive systems to control AC motor speed and torque by varying the motor input frequency and voltage. VFDs are generally used to improve performance through advances in semiconductor switching devices, drive topologies, simulation and control techniques, and control hardware and software.

[0037] It can be seen that the commutated motor / generator 22 and variable frequency device 23 are devices that manage the combination of energy supplied to the load 3 .

[0038] As will be explained in more detail below, each component of the hybrid powertrain 2 is characterized by an appropriate health index HI. In particular, the gas turbine 21 is characterized by a health index HI gt The electric motor / generator 22 is characterized by a health index HI em The variable frequency device 23 is characterized by a health index HI vfd and the photovoltaic plant PV and power plant PG lines are characterized by their associated health indices HI pv and Health Index HI pg The health index HI of each piece of equipment i can be characterized by i Through this, it is possible to associate a state with each device and subsystem and / or combination of devices and subsystems to determine their state collectively and to determine the most appropriate energy division to be produced.

[0039] Also, as the meaning of the above-mentioned health indicators HI will be better explained below, they make it possible to check the operating status of the hybrid powertrain 2 as a function of a single device and as a plant or a fleet of devices. In other words, through the health indicators HI it is possible to track the current operation of the devices of the hybrid powertrain 2 as well as the current operation of the entire hybrid powertrain 2. Overall, the train health indicator is a function of the device health indicators and can be mathematically expressed as follows:

number

[0040] In the following, with equipment any part of the hybrid powertrain 2, namely the gas turbine 21, the electric motor / generator 22 or the variable frequency device 23, and their components, will be indented.

[0041] 2, it is shown how the hybrid powertrain 2 is controlled to maximize the use of renewable energy source(s), i.e., renewable energy coming from photovoltaic plants PV in the described embodiment. In particular, the health index H of each jth appliance is j is introduced into the health index system to be determined and processed to achieve the objective function of minimizing the use of the gas turbine 21. Such an objective function can be expressed as:

number

[0042] Gas turbine combustion systems must operate in a defined operating envelope to enable a premixed combustion mode, where the fuel and air are thoroughly mixed, resulting in a broad area premixed flame with reduced diffusion flame. This reduces NO x The formation of pollutants such as CO and CO can be significantly reduced. The premixed operating envelope is limited to medium to high GT loads, and therefore the exact threshold below which premixed mode is not possible is calculated by the engine model to provide information for controlling the minimum load at which the turbine can maintain premixed mode of operation.

[0043] In addition, the load margin Δ Load is maintained above the premixed transfer threshold to ensure that the threshold is not exceeded and that the combustion does not enter a diffusion flame operating mode that produces high pollutant content.

[0044] In some embodiments, health indicator processing may occur remotely, or locally (“edge”), or a combination of the two.

[0045] In general, the plant control unit 4 (which may be a local controller of a subsystem or may be part of one) is programmed or configured to obtain an objective function based on several constraints that are based on the performance of the plant to be controlled, i.e., in this embodiment, the hybrid powertrain 2. In the embodiment shown in Figure 2, the constraints are related to the maximum energy that the electric motor / generator 22 can produce and the power range over which the gas turbine 21 can operate, i.e.:

number

[0046] As mentioned above, the plant control unit 4 of the hybrid powertrain 2 is programmed to control the operation of the hybrid powertrain 2 based on a particular computer program, as will be explained in more detail below. The control unit 4 is also operatively connected to the gas turbine 21 and any components or equipment thereof. Similarly, the plant control unit 4 is operatively connected to the electric motor / generator 22 and the variable frequency device 23. In this case, the plant control unit 4 is also programmed to control and check the components of the electric motor / generator 22 and the variable frequency device 23.

[0047] As mentioned above, the plant control unit 4 is programmed to execute a computer program to manage variable external sources (i.e., renewable energy sources such as photovoltaic plants PV) to optimize the energy production of the gas turbine 21 as well as the availability and reliability of other equipment. Also, because the LNG refrigeration plant 1 is typically energy intensive, the program reduces the need for storage (such as increased photovoltaic storage efficiency) since power is always needed. The plant control unit 4 can be remotely or hardwired to the hybrid powertrain 2 of the LNG refrigeration plant 1.

[0048] The plant control unit 4 may be connected to one or more hybrid powertrains 2, i.e., a fleet of hybrid powertrains 2. In this connection, the control unit 4 may optimize the operation of the entire fleet.

[0049] In some embodiments, and with particular reference to FIG. 3 , the plant control unit 4 may include a processor 41, a bus 42 to which the processor 41 is connected, a database 43 connected to the bus 42 so as to be accessed and controlled by the processor 41, a computer-readable memory 44 also connected to the bus 42 and thereby accessed and controlled by the processor 41, and a transceiver module 45 connected to the bus 42 for receiving and transmitting data and signals to and from the hybrid powertrain 2.

[0050] As mentioned above, the power control unit 4 is used to optimize the energy production, the energy absorbed from renewable sources, i.e., in the described embodiment, the energy absorbed from the photovoltaic plant PV, and thus the NO x and executes a program for controlling the hybrid powertrain 2 to reduce CO2 emissions.

[0051] Referring to FIG. 4, there is shown schematically the general method on which the program executed by the plant control unit 4 for controlling the LNG plant 1 is based.

[0052] Specifically, a flow chart is shown in Figure 4. Method 5 includes a detection step 51 (see Figures 4 and 5) in which the real-time conditions of the hybrid powertrain 2 are checked. In particular, in this preliminary step, the load of the gas turbine 21 and the part load of the electric motor / generator 22 are determined.

[0053] Specifically, the plant control unit 4 is connected to the gas turbine 21, the electric motor / generator 22, and the variable frequency device 23, as described above. From each of this equipment, the plant control unit 4 receives one or more input parameters P ij where index i labels one or more pieces of equipment of hybrid powertrain 2 and index j labels a parameter. Each piece of equipment may be checked through a different parameter. In the described embodiment, the equipment checked is electric motor / generator 22 and variable frequency device 23. However, additional or different equipment may be considered for this initial checking step.

[0054] Parameter P ij are signals that represent equipment performance. There will be a total of j × i parameters, i.e. j signals times i equipment. The parameter signals allow determining the degree of equipment performance. Also, their values, shapes, or spectra are affected by the maintenance needs of any particular equipment.

[0055] Each parameter signal P ij With respect to the parametric membership function M ij is assigned (step 5211, see electric motor / generator 22). This indicates the membership function of j for equipment i. Each membership function M ijcan have different forms or shapes, as can be seen in more detail in Figure 6. The parametric membership function M ij is a logic state function, and in this embodiment, each parameter P ij As a function of the value of the signal, three possible values ​​or qualification states can be assumed: Low (the equipment under analysis is not operating in proper conditions), medium (the equipment under analysis is still operating in less than optimal conditions), and high (the equipment is operating correctly). In another embodiment, the membership function M ij can assume a different number of eligibility states.

[0056] Continuing to refer to Figure 5 and also considering Figure 7, the parametric membership function M ij is the received parameter P ij Once associated with the signal, for each piece of equipment i, a parametric membership function M ij The result is a true table T i The health index HI for each i-th device is then combined through (5221). ij , from which the equipment membership function M em (see step 5231).

[0057] Therefore, with reference to the electric motor / generator 21, the parameter P em,j From the membership function M em,j The true table T em The combination rule is expressed as a membership function M em,j Applying this to the Electric Motor / Generator 21 Health Index HI em,j to calculate the membership function M of the electric motor / generator 22 of the hybrid powertrain 2. em get.

[0058] Similarly, with reference to the electric motor / generator 22, the parameter P vfd,j From the membership function M vfd,j The true table T vfd Applying the combination rules, the health index HIvfd,j and the associated membership function M vfd,j , thereby determining the membership function M of the variable frequency drive 23 of the hybrid powertrain 2. vfd Figure 7 shows an example line of code where several instrument stages are combined appropriately (see steps 5212, 5222, 5223).

[0059] The conditional subprocess 52, i.e., the membership function of each device, i.e., M em and M vfd can estimate three different outputs, i.e., three different qualified "fuzzy" states, denoted here as "Bad," "Medium," or "Good." More specifically, the first conditional step 52 is performed by computing the combined membership function Mem+vfd This combined membership function can still estimate three different output or qualified "fuzzy" states, referred to here as "Bad," "Medium," or "Good."

[0060] Joint membership function M em+vfd estimates a value of Bad, the electric motor / generator 22 and / or the variable frequency device 23 are not operating in good technical condition. A first set of operational actions is performed by the plant control unit 4 (step 53). In particular, the load on the gas turbine 21 is increased, the electric motor / generator is shut off, and the overall process load is reduced.

[0061] Membership function M em+vfdIn the case where estimates a value of Medium, the electric motor / generator 22 and variable frequency device 23 can still operate (step 54) without unduly affecting pollution or in any way impairing the operation of the hybrid powertrain 2, but the load division between the gas turbine 21 and the electric motor / generator 22 is changed. In some cases, the processing load can also be reduced. In this case, a status process that adjusts the overall train load based on the gas turbine 21-electric motor / generator 22 load capability is also communicated by the plant control unit 4.

[0062] Finally, the membership function M em+vfd In the case where estimates a Good value, the electric motor / generator 22 and the variable frequency device 23 are operating in optimum or suitable conditions.

[0063] In this case, the second conditional statement is executed (step 55) to determine the health index HI of the photovoltaic source PV. pv,j , or in general, to determine the health index of any renewable energy source. With particular reference to Figure 8, the substeps of the conditional subprocess 55 are shown. Two or more parameters P pv,j There may be (see substep 551) parameters, which are counted by index j. For each parameter P pv,j is a specific signal and true table T pv and relates to the equipment in question, namely, photovoltaic sources PV. pv is the parameter signal P of the photovoltaic plant PV pv,j This allows the application of appropriate combination rules between the PV health index HI pv Calculate the membership function M of the photovoltaic source PV. pv This allows three qualification states to be estimated: Bad, Medium, or Good.

[0064] Membership function M for photovoltaic sources PV pvIn the case where estimates a value of Bad, the photovoltaic source PV does not operate in a proper manner, and therefore the power generation unit PG is checked by implementing a third conditional subprocess 56, also shown in Figure 9. The operation check of the power generation unit PG is performed in the same way as the operation check of the photovoltaic plant 55 from a procedural point of view.

[0065] Figure 9 shows the substeps of the third conditional statement 56. Also in this case, two or more parameters P pg,j (see substep 561), there may be photovoltaic plants PV counted by index j. pg,j is the parametric membership function M pg,j , and the particular signal and truth table T pg (step 563) for the equipment in question, i.e., the power plant PG. pg is the parameter signal P of the power plant PG pg,j It allows the application of appropriate combination rules between health indicators and pg,j Each parameter signal P pg,j Then, the membership function M of the power plant PG is calculated. pg This can estimate three qualification states: Bad, Medium, and Good.

[0066] Membership function M pg If the qualification status of is Bad, the split of the load 3 is changed (go to step 53), then the load on the gas turbine 21 is increased and the electric motor / generator is shut off, reducing the overall process load.

[0067] Membership function M pgIf the value of is Medium, step 54 is performed by the plant control unit 4, i.e., the load division between the gas turbine 21 and the electric motor / generator 22 is changed. In some cases, the processing load can also be reduced. In this case, a status process that adjusts the overall train load based on the gas turbine 21-electric motor / generator 22 load capacity is also communicated by the plant control unit 4.

[0068] Finally, the membership function M pg If the value of is Good, the load sharing is maintained according to the initial state (step 57).

[0069] Returning to step 55, i.e., second conditional statement 5, the membership function M pv If estimates a value of Medium, the load on the electric motor / generator 22 is increased up to an acceptable pre-configurable threshold to act as a helper (step 58).

[0070] Finally, the membership function M for photovoltaic plants PV pv If estimates a Good value, a reallocation or different division of the power generated by the electric motor / generator 22 and the gas turbine 21 (step 59) is achieved. Specifically, the electric motor / generator 22 is operated to maximize the load as a helper (step 591), i.e., the operation of the electric motor / generator 22 and the load of the gas turbine 21 are adjusted to the "premix" transition threshold Pmx Load (step 592). Also, the objective function of minimizing the use of the gas turbine 21 is achieved. Such an objective function can be expressed by the above-mentioned equation (F2).

[0071] An advantage of the disclosed solution is that it optimizes the efficiency of the train when the typical intermittency and periodicity of renewable energies is taken into account.

[0072] A further advantage of the disclosed solution is that it ensures that LNG train availability is optimized, analyzes the health of electric motors / generators, viable frequency devices, and gas turbines, and acts on the power balance to reduce the risk of production loss.

[0073] In addition, through the disclosed solution it is possible to optimize the emissions of pollutants, CO2 (system level + fuel generated) as well as NO x and ensuring that CO2 production (produced at combustion levels) is minimized. This is also achieved by blending renewable and conventional sources.

[0074] Furthermore, the disclosed solution allows for the optimization of the overall cost of LNG production, taking into account the cost of fuel and renewable energy. This is also achieved by recognizing the health and aging of equipment for maintenance scheduling and plant availability optimization. The analyzed equipment includes generators, motors, and variable frequency devices (i.e., partial discharge, dedicated instrumentation installed). In particular, equipment data monitoring and analysis (real-time or post-processing) allows for the recognition and optimization of operating conditions that may affect production.

[0075] Awareness of VFD and motor health for maintenance scheduling and optimize plant availability.

[0076] Gas turbine operating profile optimization to minimize pollutants in general, not limited to CO2 but also considering NOx.

[0077] A further advantage of the present disclosure is that by simply optimizing the operation of the trains, the carbon intensity of the LNG plant can be reduced by 10% to 15% without affecting productivity, availability and reliability, and flexibility in managing hot gas components can be increased.

[0078] Another advantage of the disclosed method is that it makes renewable power storage optional (the LNG process consumes the energy produced) and maximizes renewable RTE, in combination with the architecture of the train itself, through advanced control of the LNG train, to substantially optimize the RTE of renewable utilization and the CAPEX of the renewable source.

[0079] While aspects of the present invention have been described in terms of 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. Additionally, unless otherwise specified herein, the order or sequence of any process or method steps may be varied or rearranged according to alternative embodiments.

[0080] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not as a limitation of the disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. References throughout this specification to "one embodiment" or "an embodiment" or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the disclosed subject matter. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," or "in some embodiments" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0081] When presenting elements of various embodiments, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be non-exclusive and mean that there may be additional elements other than the listed elements.

Claims

1. A hybrid powertrain (2), a through shaft (24); a gas turbine (21) mechanically connected to the shaft (24); an electric motor / generator (22) mechanically connected to said shaft (24); a variable frequency device (23) connected to an electric motor / generator (22), a power plant (PG), and a renewable energy source (PV), the variable frequency device (23) operable to enable the electric motor / generator (22) to convert energy from the power plant (PG) and the renewable energy source (PV) to drive a load (3) or assist in the operation of the gas turbine (21); a plant control unit (4) operatively connected to the gas turbine (21), the electric motor / generator (22), and the variable frequency device (23); the plant control unit (4) is configured to control the hybrid powertrain (2) to maximize the used energy coming from the renewable energy source (PV) by maximizing the drive load of the electric motor / generator (22); The load is the combustor premix transition threshold (Pmx Ｌｏａｄ ) is maintained above the hybrid powertrain (2); the load (3) mechanically connected to the shaft (24); A power plant (1) comprising:

2. The load is the combustor premix transition threshold (Pmx Ｌｏａｄ ) and a constant load margin (Δ Ｌｏａｄ 2. The power plant (1) of claim 1, wherein the power supply voltage Vcc is maintained above the sum of Vcc and Vcc.

3. The plant control unit (4) A processor (41); A bus (42), wherein the processor (41) is connected to the bus (42): a database (43) connected to the bus (42) so as to be accessed and controlled by the processor (41); a computer-readable memory (44) connected to the bus (42) and thereby accessed and controlled by the processor (41); and a transceiver module (45) connected to the bus (42) for receiving and transmitting data and signals to and from the hybrid powertrain (2); a bus (42) connected to 3. The power plant (1) according to claim 1 or 2, comprising:

4. 2. The power plant (1) according to claim 1, wherein the renewable energy source is a photovoltaic plant (PV) and / or a wind power plant and / or a concentrated solar power system.

5. 2. The power plant (1) of claim 1, wherein the load comprises one or more centrifugal compressors (31, 32) for cooling natural gas.

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