Gas pressure threshold adaptive turbine dual fuel switching control method

Abstract

The present application provides a turbine dual-fuel switching control method with adaptive gas pressure threshold, belonging to the technical field of turbine generator set, and applied to turbine units that have completed dual-fuel modification. The method retains the original manual oil switching function, constructs a near-point turbine inlet side and a far-point gas buffer tank double-pressure acquisition unit, adaptively calculates the oil switching pressure threshold based on the ideal gas state equation and the dynamic working condition correction model, configures a double-path trigger mechanism, and when any path meets the trigger condition, the turbine control system automatically executes the gas-to-oil switching program. The present application solves the problems of traditional manual oil switching, such as dependence on manual operation, response lag, fuel waste, etc., and the oil switching time is ≤1 min, the power fluctuation is ≤300 kW, which significantly improves the stability, economy and risk resistance of the unit operation, and is especially suitable for scenes with high requirements for power supply reliability, such as offshore platforms.

Description

Technical Field

[0001] This invention belongs to the field of turbine generator set technology, and more specifically, relates to a turbine dual-fuel switching control method with adaptive gas pressure threshold. Background Technology

[0002] Turbine generator sets are core power supply equipment for offshore platforms, natural gas power plants, and other similar applications, and their operational stability directly affects the continuity of production operations. A turbine unit on a platform in Wenchang originally operated in a single gas-fired mode, which had significant drawbacks: insufficient gas supply easily triggered low-pressure shutdowns, leading to power supply fluctuations and impacting oilfield production and drilling operations; furthermore, it could not be started with diesel fuel during black starts, resulting in extremely poor operational flexibility.

[0003] To improve this situation, the unit underwent a dual-fuel nozzle retrofit in August 2025. After the retrofit, manual switching between natural gas and oil was enabled. Testing showed that the oil switching time was consistently controlled within 1 minute, and the unit's power fluctuation during mode switching was ≤300kW, basically meeting the platform's operational requirements. However, key technical defects remain after the retrofit: the oil switching operation relies entirely on operators monitoring the gas pressure in real time and triggering the switching command manually via a button on the control cabinet. This is not only labor-intensive but also carries significant risks of response lag and operational errors. When the gas pressure drops sharply, the delay in manual intervention can easily lead to unit load fluctuations or even shutdown. Furthermore, manual operation cannot precisely control the timing of the oil switching; switching too early can cause frequent switching, grid fluctuations, and fuel waste, while switching too late may result in insufficient gas supply to the unit, further affecting power supply stability.

[0004] The existing manual fuel switching mode of dual-fuel turbine units can no longer meet the high requirements of power supply reliability and economy in scenarios such as offshore platforms. There is an urgent need for a control method that can automatically, accurately and quickly switch fuels to make up for the shortcomings of manual operation and ensure the continuous and stable operation of the unit. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a turbine dual-fuel switching control method with adaptive gas pressure threshold. This method solves the technical problems of response lag, operational errors, fuel waste, inaccurate switching timing, and impact on grid stability caused by relying solely on manual fuel switching in turbine units after dual-fuel conversion. It also meets the high requirements for power supply reliability in scenarios such as offshore platforms.

[0006] A turbine dual-fuel switching control method with adaptive gas pressure threshold is applied to turbine units that have completed dual-fuel retrofitting. It retains the original manual oil switching function and achieves automatic switching from gas to oil through dual pressure acquisition, adaptive threshold calculation, and dual-path triggering. The method includes the following steps:

[0007] S1: Construct a dual pressure acquisition unit: Set up a near-point pressure acquisition end and a far-point pressure acquisition end. The near-point pressure acquisition end acquires the pressure on the gas inlet side of the turbine unit, and the far-point pressure acquisition end acquires the pressure inside the gas buffer tank. The two acquisition signals are mutually backed up.

[0008] S2: Build an adaptive threshold calculation module: collect unit operating parameters in real time, and dynamically calculate the near-point pressure threshold P1 and far-point pressure threshold P2 based on the ideal gas equation of state and dynamic operating condition correction model. The operating parameters include the gas buffer tank volume V, the unit's real-time gas consumption Q, the near-point minimum stable operating pressure Pmin, the oil switching time tswitch, and the pipeline transmission loss ΔP between the near-point and far-point.

[0009] S3: Configure a dual-path triggering module: The near-point pressure acquisition end outputs a trigger signal through a mechanical pressure switch, and the far-point pressure acquisition end outputs a trigger signal after the pressure sensing signal is delayed and filtered.

[0010] S4: Switching control: When either path in the dual-path triggering module meets the triggering condition, the turbine control system receives the signal and executes the switching procedure from gas mode to fuel mode according to the preset timing sequence, completing the automatic fuel switch.

[0011] Preferably, in step S1:

[0012] The installation position of the near-point pressure acquisition terminal is between the external gas shut-off valve of the turbine housing and the first-stage shut-off valve inside the housing.

[0013] The remote pressure acquisition terminal is installed at the turbine gas buffer tank, and pressure acquisition is achieved using the existing pressure sensor that has been connected to the central control PCS system.

[0014] Preferably, in step S1:

[0015] The near-point pressure acquisition terminal adopts a mechanical pressure switch, and the mechanical pressure switch is connected to the turbine control system with normally closed contacts;

[0016] The remote pressure acquisition terminal uses a pressure transmitter to convert the acquired pressure signal into a 4-20mA AI signal and transmit it to the central control PCS system.

[0017] Preferably, the calculation process of the adaptive threshold calculation module in step S2 includes:

[0018] Based on the simplified model of the ideal gas law t=V×(P0-Pmin) / Q, the turbine's operating time t is calculated to ensure that t≥tswitch;

[0019] The theoretically optimal threshold P1opt for the nearest point is calculated using the formula P1opt=Pmin+(Q×tswitch) / V, and the dynamic threshold P1 is obtained after reserving a safety margin.

[0020] Combining the pipeline transmission loss ΔP=P01-P02 (where P01 is the normal operating pressure at the far point and P02 is the normal operating pressure at the near point), the dynamic threshold at the far point P2=P1+ΔP is derived.

[0021] Preferably, the triggering logic of the near-point pressure acquisition terminal in step S3 is as follows: when the near-point acquisition pressure is ≤ dynamic threshold P1, the mechanical pressure switch contact closes and outputs a DO signal to the turbine control system to trigger emergency oil switching.

[0022] Preferably, the triggering logic of the remote pressure acquisition terminal in step S3 is as follows: the central control PCS system performs delay filtering on the received AI signal to eliminate instantaneous pressure fluctuation interference. When the remote acquisition pressure is ≤ dynamic threshold P2 and the duration is ≥ 2s, the DO signal is output to the turbine control system to trigger the predictive oil switching.

[0023] Preferably, the linkage mechanism of the dual-path triggering module in step S4 is as follows: the near-point triggering signal and the far-point triggering signal are independent of each other. When either signal is valid, the turbine control system immediately starts the oil switching procedure, and the two path triggering signals do not conflict.

[0024] Preferably, the adjustment mechanism of the adaptive threshold calculation module in step S2 is as follows: when the change in the real-time operating parameters of the unit exceeds the preset threshold ±10%, the dynamic thresholds P1 and P2 are recalculated to achieve real-time adaptive updating of the thresholds.

[0025] Preferably, the retained manual oil switching function and automatic oil switching function can operate independently. The manual trigger signal is generated by the control cabinet button and input to the turbine control system in parallel with the automatic trigger signal, and there is no mechanical or logical conflict between the two when switching.

[0026] Preferably, the execution standard for the oil switching procedure in step S4 is: oil switching time ≤ 1 min, unit power fluctuation ≤ 300 kW, which is suitable for scenarios such as offshore platforms with high requirements for power supply reliability.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention employs a dual-path triggering mechanism combining a near-point mechanical pressure switch and a far-point pressure sensor, eliminating the need for manual monitoring and intervention. It automatically triggers fuel switching when gas pressure is abnormal. The near-point path exhibits strong anti-interference capabilities and can quickly respond to sudden pressure drops; the far-point path, after delay filtering, can predict pressure trends and switch fuel earlier, effectively avoiding the response lag, judgment errors, and switching delays associated with manual operation, ensuring timely and accurate fuel switching.

[0029] Based on the ideal gas law and a dynamic operating condition correction model, the switching pressure threshold is adaptively calculated. This avoids both frequent switching and excessive fuel consumption caused by premature switching and unit fluctuation risks caused by delayed switching. By precisely controlling the timing of switching, fuel consumption is minimized while ensuring stable operation, thus reducing unit operating costs.

[0030] The dual pressure acquisition units are mutually backed up, and the dual-path triggering mechanism is independently linked. If one path fails, the other path can still work normally. At the same time, the original manual oil switching function is retained, forming an "automatic + manual" dual protection mode. This effectively copes with sudden situations such as pressure fluctuations and equipment failures under complex working conditions of offshore platforms, avoids unit shutdown or power outages, and ensures the continuous operation of oilfield production and drilling operations.

[0031] This invention is based on the existing dual-fuel conversion of the unit. The remote pressure acquisition reuses the original pressure transmitter and central control PCS system. Only the near-point mechanical pressure switch and the optimized control program need to be added. There is no need to make major modifications to the unit's main unit and core pipelines. It has good compatibility with the original system, short conversion cycle, controllable cost, and is easy to promote and apply.

[0032] The control method of this invention can flexibly adjust parameters through an adaptive threshold calculation module according to parameters such as the gas buffer tank volume, rated gas consumption, and pressure operating range of different turbine units. It is not only applicable to offshore platform turbine units, but also adaptable to various scenarios with high requirements for power supply reliability, such as onshore natural gas power plants and turbine units for industrial production, making it highly practical. Attached Figure Description

[0033] Figure 1 This is a simplified diagram of the newly added program in the central control PCS of this invention;

[0034] Figure 2 This is a schematic diagram of the dual-path oil transfer logic linkage mechanism in this invention;

[0035] Figure 3 This is the gas shear oil under 5500kW operating conditions in this invention;

[0036] Figure 4 This is the gas shear oil under 3000kW operating conditions in this invention;

[0037] Figure 5 It is the gas-shearing oil under the 1500kW operating condition in this invention. Detailed Implementation

[0038] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0039] Please see Figure 1-5 This invention provides a turbine dual-fuel switching control method with adaptive gas pressure threshold. This embodiment is based on a turbine unit on a marine platform in Wenchang that has completed dual-fuel conversion, ensuring that the implementation process is repeatable and verifiable.

[0040] Implementation prerequisites and equipment preparation:

[0041] 1. Basic conditions of the unit:

[0042] The turbine unit in this embodiment has completed the dual-fuel nozzle retrofit (retrofit time: August 2025) and has the function of manual switching between gas and oil. The key parameters after the retrofit are as follows:

[0043] The gas buffer tank has a volume of V = 30 m³.

[0044] The normal operating pressure of the remote gas buffer tank is P01 = 30 MPa;

[0045] The normal operating pressure at the near point (between the external gas shut-off valve and the primary shut-off valve inside the turbine housing) is P02 = 24 MPa.

[0046] The minimum stable operating pressure of the turbine near the point of contact is Pmin = 12 MPa;

[0047] The rated gas consumption of the turbine unit is Q = 66.7 m³ / min (under standard conditions).

[0048] Manual oil switching test verification: oil switching time ≤ 1min, power fluctuation ≤ 300kW, meeting the basic requirements for platform operation.

[0049] 2. Core equipment selection and adaptation:

[0050] Equipment Name Model / Specification Installation location Functions and uses Mechanical pressure switch PS3701 (Normally Closed Contact) The nearest point (between the external gas shut-off valve and the internal primary shut-off valve of the turbine housing). Collect near-point gas pressure and output DO trigger signal. pressure transmitter Existing (already connected to the central control PCS system) Far away (gas buffer tank) Collects gas pressure at remote locations and outputs 4-20mA AI signals. Turbine control system Original unit control system (compatible with DO signal input) Inside the unit control cabinet Receive the oil switching trigger signal and execute the switching procedure. Central Control PCS System Existing (supports program extensions) Platform control room Processing remote pressure signals to implement time delay filtering and threshold judgment Signal transmission cable Shielded DO signal cable, 4-20mA AI signal cable Between the pressure acquisition terminal and the control system Ensure interference-resistant transmission of pressure signals

[0051] Dual pressure acquisition unit construction, installation and commissioning:

[0052] 1. Installation of the near-point pressure acquisition terminal:

[0053] Installation location: Strictly follow the turbine gas flow PID drawing to select the pipeline position between the external gas shut-off valve (XV3701) and the internal first-stage shut-off valve (XV3702) of the turbine housing. This position directly reflects the turbine inlet gas pressure and has a fast response speed.

[0054] Installation process: Fix the PS3701 mechanical pressure switch to the gas pipeline through the flange interface (DN25-Class300, material 022Cr22Ni5Mo3N) to ensure that the sealing performance meets the 3.5MPa pressure rating requirement, and that the pressure sensing element is in close contact with the inner wall of the pipeline with no pressure transmission delay;

[0055] Wiring configuration: The turbine control system is connected via normally closed contacts. The power supply is 24VDC, and the signal line is a shielded DO line. The terminals are securely fastened and insulated to avoid corrosion and interference in the marine environment.

[0056] 2. Remote pressure acquisition terminal adapter:

[0057] Equipment reuse: The original pressure transmitter of the gas buffer tank (already connected to the PCS system, model PIT4003) can be reused without adding new hardware equipment, and the signal can be reused only through the PCS system program expansion.

[0058] Signal verification: Check the signal transmission status of the pressure transmitter to ensure that the linearity error of its output 4-20mA AI signal is ≤±0.5%, and that it transmits stably under the rated pressure of 30MPa without drift.

[0059] Delay filtering module deployment: Add a signal processing program to the central control PCS system, set a 2-second delay filtering logic to eliminate the interference of instantaneous pressure fluctuations (such as pulse fluctuations during gas delivery) on trigger judgment. A simplified program diagram is shown below. Figure 2 As shown.

[0060] 3. Data Acquisition Unit Integration and Debugging:

[0061] Pressure signal calibration: The near-point mechanical pressure switch and the far-point pressure transmitter are calibrated using a standard pressure source to ensure that the pressure measurement error is ≤±1%;

[0062] Signal transmission test: Simulate the pressure at the near point decreasing from 24MPa to 16MPa and the pressure at the far point decreasing from 30MPa to 22MPa to verify that the DO signal and AI signal have no packet loss or delay during transmission, and that both the turbine control system and the central control PCS system can accurately receive the signals.

[0063] Adaptive threshold calculation module configuration and parameter settings:

[0064] 1. Basic parameter entry:

[0065] In the adaptive threshold calculation module of the turbine control system, input the basic parameters of the unit's operating conditions:

[0066] Fixed parameters: The volume of the gas buffer tank V = 30 m³, the minimum stable operating pressure at the near point Pmin = 12 MPa, the oil transfer duration tswitch = 1 min, and the maximum pipeline transmission loss ΔP = P01 - P02 = 6 MPa;

[0067] Dynamic parameter interface: Reserve the acquisition interface for the real-time gas consumption Q of the unit. Calculate the dynamic gas consumption in real time through the feedback signals of the unit's fuel regulating valve and gas regulating valve, and the update period is 1 s.

[0068] 2. Deployment of threshold calculation logic:

[0069] Based on the ideal gas state equation and the dynamic operating condition correction model, write a threshold calculation program in the turbine control system. The specific process is as follows:

[0070] Feasibility prediction calculation: Calculate the available operating duration t of the turbine in real time through the formula t = V×(P0 - Pmin) / Q. When t ≥ tswitch (1 min), it is determined that the current operating condition meets the automatic oil transfer condition, and the threshold calculation module is started; when t < tswitch, the system issues a warning signal to prompt the operator to check the gas supply;

[0071] Calculation of the near-point dynamic threshold P1:

[0072] Theoretical optimal threshold: Calculated through the formula P1opt = Pmin + (Q×tswitch) / V. For example, when Q = 66.7 m³ / min, P1opt = 12 + (66.7×1) / 30 ≈ 14.22 MPa;

[0073] Safety margin correction: Considering the risk of gas pressure fluctuations on the offshore platform (such as unstable gas transmission caused by wind and waves), reserve a safety margin of 1.78 MPa, and finally determine the near-point dynamic threshold P1 = 16 MPa;

[0074] Calculation of the far-point dynamic threshold P2: Combining the pipeline transmission loss ΔP = 6 MPa, deduce through the formula P2 = P1 + ΔP to determine the far-point dynamic threshold P2 = 22 MPa;

[0075] Threshold adaptive update: Set the trigger condition for changes in operating condition parameters. When the change range of the unit's real-time gas consumption Q exceeds ±10%, the threshold calculation module re-executes the above calculation process to update P1 and P2 to ensure that the threshold always adapts to the current operating condition.

[0076] 3. Threshold parameter固化 and permission setting:

[0077] Parameter固化: Enter the calculated initial thresholds P1 = 16 MPa and P2 = 22 MPa into the turbine control system and the central control PCS system, and set the parameter modification permission. Only authorized operators can perform calibration adjustments; It should be noted that the word "固化" in Chinese is not accurately translated as there may be a more appropriate term in the context of technical jargon. If there is a specific English equivalent for this term in the relevant technical field, it should be used instead. Here, it is tentatively left as "固化" for lack of more context information.

[0078] Threshold range limitation: Set threshold safety boundaries. The adjustment range of P1 is 14MPa~18MPa, and the adjustment range of P2 is 20MPa~24MPa to avoid abnormal oil switching due to incorrect parameter settings.

[0079] Dual-path triggering module and switching control execution:

[0080] 1. Implementation of the nearest emergency oil transfer route:

[0081] Triggering logic: The PS3701 mechanical pressure switch adopts a normally closed contact design. When the near-point gas pressure is higher than P1 (16MPa), the pressure will open the switch contact and there will be no signal output; when the pressure is ≤16MPa, the contact will close and output a DO signal to the turbine control system.

[0082] Response mechanism: After receiving the DO signal, the turbine control system immediately starts the emergency fuel switch procedure, skips the delay judgment, and performs the switch from gas mode to fuel mode according to the preset sequence. The specific sequence is as follows: gas shut-off valve (XV3701, XV3702) closes → fuel purge shut-off valve (XV4002) opens → fuel ring pipe is filled (filling time is about 25s) → fuel injector starts → gas mode exits. The entire fuel switch time is ≤1min.

[0083] 2. Implementation of far-point predictive oil switching path:

[0084] Signal processing: The pressure signal collected by the gas buffer tank pressure transmitter is converted into a 4-20mA AI signal and then transmitted to the central control PCS system. After a 2s delay and filtering, instantaneous fluctuation interference is eliminated.

[0085] Triggering logic: When the central control PCS system detects that the remote pressure is ≤P2 (22MPa) and the duration is ≥2s, it outputs a DO signal to the turbine control system;

[0086] Response mechanism: After receiving the signal, the turbine control system initiates a predictive oil switching procedure, which follows a smooth switching logic of "gradually decreasing gas supply → gradually increasing fuel oil supply" to avoid excessive power fluctuations and ensure that the unit's power fluctuation is ≤300kW.

[0087] 3. Dual-path linkage and manual function compatibility:

[0088] Linkage mechanism: The near-point trigger signal and the far-point trigger signal are independent of each other. When either signal is valid, the turbine control system immediately executes the oil switching procedure, and the two path signals do not conflict (when the two signals are triggered at the same time, the timing of the near-point emergency oil switching path is executed first).

[0089] Manual function retained: The original manual oil switching button on the control cabinet is retained. The manual trigger signal and the automatic trigger signal are input to the turbine control system in parallel. The signal priority is set (manual signal has higher priority than automatic signal). When the operator triggers the manual oil switching, the automatic oil switching function is temporarily disabled. It will be automatically restored after the switch is completed, ensuring that there is no mechanical or logical conflict between manual and automatic modes.

[0090] Functional testing and verification:

[0091] 1. Test Condition Design:

[0092] With sufficient grid backup, tests were conducted under three typical operating conditions: 1500kW, 3000kW, and 5500kW. The tests simulated two scenarios: natural gas pressure drop and sudden gas pressure drop. Each scenario was tested three times, and indicators such as oil switching time, power fluctuation, and trigger accuracy were recorded.

[0093] 2. Test process and results:

[0094] Test conditions Simulation scenario Trigger path Turnaround time Power fluctuation Trigger accuracy 1500kW Gas pressure drops naturally Remote pressure sensing 52s 210kW 100% 1500kW Gas pressure drops sharply Near-point mechanical pressure switch 48s 250kW 100% 3000kW Gas pressure drops naturally Remote pressure sensing 55s 280kW 100% 3000kW Gas pressure drops sharply Near-point mechanical pressure switch 50s 290kW 100% 5500kW Gas pressure drops naturally Remote pressure sensing 58s 295kW 100% 5500kW Gas pressure drops sharply Near-point mechanical pressure switch 53s 300kW 100%

[0095] Test results show that the automatic oil switching function can be accurately triggered under all three operating conditions, with an oil switching time of ≤1min and a power fluctuation of ≤300kW, meeting the platform operation requirements; the dual-path triggering is conflict-free, and the adaptive threshold can be automatically fine-tuned according to the slight changes in gas consumption (within ±5%), ensuring the economy and safety of the oil switching timing.

[0096] 3. Manual-Automatic Switching Test:

[0097] Triggering the manual oil switching button temporarily disables the automatic oil switching function. After the manual oil switching is completed (oil switching time 56s, power fluctuation 270kW), the system automatically restores the automatic oil switching function without any logical conflict. When the manual oil switching is triggered during the simulation of automatic oil switching, the system immediately switches to manual control to ensure operational flexibility.

[0098] Operation, maintenance, and threshold calibration:

[0099] 1. Regular maintenance cycle and content:

[0100] Daily inspection: Check the installation and sealing of the near-point mechanical pressure switch, the connection status of the signal line, and verify the stability of the remote pressure signal in the central control PCS system;

[0101] Weekly calibration: The near-point mechanical pressure switch and the far-point pressure transmitter are calibrated using a standard pressure source to ensure threshold trigger accuracy;

[0102] Monthly threshold review: Based on actual unit operating data (such as gas consumption trends and gas pressure fluctuation patterns), review the rationality of the adaptive threshold and make manual fine-tuning when necessary.

[0103] 2. Fault handling mechanism:

[0104] Signal loss handling: When the pressure signal at the near point or far point is lost, the system automatically switches to the other path to work independently and issues a fault warning; when both path signals are lost, the system locks the automatic oil switching function and forces a switch to manual mode to avoid accidental triggering.

[0105] Threshold anomaly handling: When the adaptive threshold calculation result exceeds the safety boundary (P1<14MPa or P1>18MPa, P2<20MPa or P2>24MPa), the system retains the previous valid threshold and issues an early warning to prompt the operator to check the operating condition parameter acquisition interface.

[0106] This embodiment is based on an offshore platform turbine unit, but the control method of the present invention is also applicable to other scenarios with high requirements for power supply reliability (such as onshore natural gas power plants, turbine units for industrial production, etc.). It can be quickly adapted by simply re-entering the basic parameters through the adaptive threshold calculation module according to the target unit's gas buffer tank volume, rated gas consumption, pressure operating range, and other parameters, without the need for major adjustments to the hardware structure.

[0107] Through the above specific implementation methods, the present invention realizes the adaptive adjustment of the gas pressure threshold of the turbine unit and the automatic oil switching of dual paths, which solves the problems of traditional manual oil switching relying on manual labor, delayed response, and fuel waste. At the same time, the manual function is retained as a backup, which greatly improves the stability, economy and reliability of the unit operation.

[0108] This invention is implemented based on a turbine unit on a marine platform in Wenchang that has already undergone dual-fuel conversion. Through systematic hardware adaptation, software development, and joint debugging and testing, the feasibility, stability, and superiority of the turbine dual-fuel switching control method with adaptive gas pressure threshold are fully verified. The entire implementation process focuses on solving industry pain points, optimizing operational efficiency, and lowering the application threshold. It fully reuses existing equipment resources and breaks through the limitations of the traditional manual fuel switching mode through precise technological innovation, providing a complete solution for fuel switching control of turbine generator units that is both scientific and practical.

[0109] From a technological innovation perspective, the core breakthrough of this invention lies in constructing a closed-loop control system of dual acquisition, self-adaptation, and dual triggering, completely changing the traditional mode that relies on manual judgment. The design of the dual pressure acquisition unit embodies the collaborative logic of near-point response and far-point prediction.

[0110] The near-point mechanical pressure switch, installed at a critical node on the turbine inlet side, can quickly detect emergency scenarios such as sudden pressure drops. It directly outputs a trigger signal through normally closed contacts, achieving millisecond-level emergency fuel switching and effectively avoiding the risk of unit shutdown due to gas supply interruptions. The remote-point pressure transmitter reuses existing equipment and, after delay filtering by the central control PCS system, can accurately identify pressure trends and initiate predictive fuel switching in advance. This avoids fuel waste caused by premature switching and power fluctuations caused by delayed switching. This dual-path independent linkage mechanism not only ensures the timeliness and accuracy of fuel switching but also enhances the system's fault tolerance through signal backup. Even if one path experiences signal loss or equipment failure, the other path can still independently complete the triggering task, building a solid safety barrier for unit operation.

[0111] The development and deployment of the adaptive threshold calculation module is a key support for achieving "precise oil switching and economical operation." This invention abandons the rigid mode of traditional fixed thresholds, constructs a simplified model based on the ideal gas law, and dynamically adjusts the pressure threshold in conjunction with the real-time operating parameters of the unit, achieving real-time matching between the threshold and the operating state. The feasibility of oil switching is ensured by calculating the turbine's operational duration, the near-point threshold is determined by calculating the theoretically optimal threshold and combining it with safety margin correction, and the far-point threshold is derived by combining it with pipeline transmission losses. The entire calculation process balances scientific rigor and scientific accuracy, while also fully considering the pressure fluctuation characteristics of complex scenarios such as offshore platforms. When the real-time gas consumption of the unit changes by more than ±10%, the system automatically recalculates the threshold to ensure that the timing of switching to fuel oil can be accurately controlled under different load conditions. In tests of three typical operating conditions of 5500kW, 3000kW, and 1500kW, the switching time to fuel oil was controlled within 1 minute, and the power fluctuation did not exceed 300kW. This not only met the platform's stringent requirements for power supply stability but also minimized fuel consumption. Calculations show that this can reduce fuel waste by about 15%-20%, significantly improving the economic efficiency of the unit's operation.

[0112] In terms of compatibility and promotional value, this invention demonstrates strong practical advantages. The entire control method is based on the existing dual-fuel conversion of the unit, requiring no major modifications to key equipment such as the turbine main unit and core pipelines. The remote pressure acquisition directly reuses the original pressure transmitter and central control PCS system, requiring only the addition of a near-point mechanical pressure switch and optimized control program. The conversion cycle is short (in this embodiment, it only took 15 days from equipment installation to commissioning), and the cost is controllable (the cost of the new hardware is less than 5% of the total investment in the unit conversion). It has excellent compatibility with the original system and can be quickly applied to various turbine units that have completed dual-fuel conversion. At the same time, the design of retaining the manual oil switching function fully considers the operating habits and emergency response needs of operators. The manual and automatic modes operate independently in parallel without mechanical or logical conflicts, and the manual signal has higher priority than the automatic signal. This ensures a smooth transition to intelligent upgrades and reserves operational space for manual intervention in emergency scenarios, improving the operability and acceptability of the method.

[0113] From the implementation results, the application of this invention has completely solved many pain points of the traditional manual oil switching mode. Test data shows that the trigger accuracy of automatic oil switching reaches 100% under three typical operating conditions, the oil switching time is stably controlled between 48s and 58s, and the maximum power fluctuation does not exceed 300kW, fully meeting the requirements of offshore platforms for the continuity and stability of power supply. Compared with manual oil switching, the automatic switching mode does not require operators to monitor pressure data in real time, significantly reducing labor intensity, eliminating the risks caused by human judgment errors and response delays, and effectively avoiding problems such as grid fluctuations, fuel waste, or unit shutdowns caused by improper oil switching timing. In the actual operation of offshore platforms, this method has successfully coped with complex scenarios such as gas transmission fluctuations caused by wind and waves and pipeline pressure pulse interference, ensuring the continuous operation of oilfield production and drilling operations. Its "automatic + manual" dual guarantee mode provides a higher level of reliability support for power supply in critical scenarios.

[0114] The value of this invention extends beyond applications on single offshore platforms, possessing broad applicability and significant industry-wide implications. Beyond offshore platforms, this control method can be rapidly adapted to various scenarios with high power supply reliability requirements, such as onshore natural gas power plants and industrial turbine units, by adjusting basic parameters (e.g., gas buffer tank volume, minimum stable operating pressure, pipeline transmission losses). Its core control logic can be migrated to dual-fuel turbine units of different power levels and fuel types, making it particularly suitable for operating environments with unstable gas supply and significant load fluctuations. Furthermore, the technical approach of this invention provides valuable insights for the intelligent upgrading of turbine generator sets. Through a combination of lightweight hardware modifications and intelligent software optimization, it achieves efficiency improvements in traditional equipment, aligning with the current trend of intelligent and energy-efficient industrial equipment development.

[0115] In terms of operation, maintenance, and sustainability, this invention establishes a comprehensive support system. A regular maintenance mechanism, including daily inspections, weekly calibrations, and monthly threshold verifications, ensures the measurement accuracy and signal transmission stability of the pressure acquisition equipment. For fault scenarios such as signal loss and abnormal thresholds, a clear emergency handling procedure is designed. The system can automatically switch operating modes and issue early warnings, reducing the impact of faults on operation. This combination of precise control and standardized maintenance not only ensures the long-term stable operation of the method but also extends the equipment's lifespan, further reducing the unit's total life-cycle operating costs.

[0116] In summary, the gas pressure threshold adaptive dual-fuel switching control method for turbines addresses industry pain points through technological innovation, ensures operational efficiency through precise implementation, and lowers the barriers to adoption through compatible design. Its significant advantages in stability, economy, and reliability make it the preferred solution for fuel switching control of dual-fuel turbine units. The successful implementation and promotion of this invention will not only provide more reliable power supply for offshore platforms, natural gas power plants, and other scenarios, but will also drive the development of turbine generator control technology towards intelligence and adaptability, injecting new impetus into the efficient and low-carbon operation of the energy industry. In the future, with further technological optimization, it can be combined with technologies such as the Internet of Things and big data analysis to achieve advance prediction of operating parameters and accurate forecasting of thresholds, further improving the intelligence level of fuel switching and providing more comprehensive support for the safe, economical, and stable operation of turbine units.

[0117] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A turbine dual-fuel switching control method with adaptive gas pressure threshold, applied to turbine units that have completed dual-fuel retrofitting, characterized in that, The original manual fuel switching function is retained, and automatic switching from natural gas to fuel is achieved through dual pressure acquisition, adaptive threshold calculation, and dual-path triggering, including the following steps: S1: Construct a dual pressure acquisition unit: Set up a near-point pressure acquisition end and a far-point pressure acquisition end. The near-point pressure acquisition end acquires the pressure on the gas inlet side of the turbine unit, and the far-point pressure acquisition end acquires the pressure inside the gas buffer tank. The two acquisition signals are mutually backed up. S2: Build an adaptive threshold calculation module: collect unit operating parameters in real time, and dynamically calculate the near-point pressure threshold P1 and far-point pressure threshold P2 based on the ideal gas equation of state and dynamic operating condition correction model. The operating parameters include the gas buffer tank volume V, the unit's real-time gas consumption Q, the near-point minimum stable operating pressure Pmin, the oil switching time tswitch, and the pipeline transmission loss ΔP between the near-point and far-point. S3: Configure a dual-path triggering module: The near-point pressure acquisition end outputs a trigger signal through a mechanical pressure switch, and the far-point pressure acquisition end outputs a trigger signal after the pressure sensing signal is delayed and filtered. S4: Switching control: When either path in the dual-path triggering module meets the triggering condition, the turbine control system receives the signal and executes the switching procedure from gas mode to fuel mode according to the preset timing sequence to complete the automatic fuel switch. The calculation process of the adaptive threshold calculation module in step S2 includes: Based on the simplified model of the ideal gas law t=V×(P0-Pmin) / Q, the turbine's operating time t is calculated to ensure that t≥tswitch; The theoretically optimal threshold P1opt for the nearest point is calculated using the formula P1opt=Pmin+(Q×tswitch) / V, and the dynamic threshold P1 is obtained after reserving a safety margin. Combining the pipeline transmission loss ΔP=P01-P02, the dynamic threshold at the far point is derived as P2=P1+ΔP.

2. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, In step S1: The installation position of the near-point pressure acquisition terminal is between the external gas shut-off valve of the turbine housing and the first-stage shut-off valve inside the housing. The remote pressure acquisition terminal is installed at the turbine gas buffer tank, and pressure acquisition is achieved using the existing pressure sensor that has been connected to the central control PCS system.

3. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, In step S1: The near-point pressure acquisition terminal adopts a mechanical pressure switch, and the mechanical pressure switch is connected to the turbine control system with normally closed contacts; The remote pressure acquisition terminal uses a pressure transmitter to convert the acquired pressure signal into a 4-20mA AI signal and transmit it to the central control PCS system.

4. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, The triggering logic of the near-point pressure acquisition terminal in step S3 is as follows: when the near-point acquisition pressure is less than or equal to the dynamic threshold P1, the mechanical pressure switch contacts close and output a DO signal to the turbine control system to trigger an emergency oil switch.

5. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, The triggering logic of the remote pressure acquisition terminal in step S3 is as follows: the central control PCS system performs delay filtering on the received AI signal to eliminate instantaneous pressure fluctuation interference. When the remote acquisition pressure is ≤ dynamic threshold P2 and the duration is ≥ 2s, the DO signal is output to the turbine control system to trigger the predictive oil switching.

6. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, The linkage mechanism of the dual-path triggering module in step S4 is as follows: the near-point triggering signal and the far-point triggering signal are independent of each other. When either signal is valid, the turbine control system immediately starts the oil switching procedure, and the two path triggering signals do not conflict.

7. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, The adjustment mechanism of the adaptive threshold calculation module in step S2 is as follows: when the change in the real-time operating parameters of the unit exceeds the preset threshold ±10%, the dynamic thresholds P1 and P2 are recalculated to achieve real-time adaptive updating of the thresholds.

8. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, The retained manual and automatic oil switching functions can operate independently. The manual trigger signal is generated by the control cabinet button and input to the turbine control system in parallel with the automatic trigger signal, and there is no mechanical or logical conflict between the two when switching.

9. The turbine dual-fuel switching control method with adaptive gas pressure threshold according to claim 1, characterized in that, The execution standard for the oil switching procedure in step S4 is: oil switching time ≤ 1 min, unit power fluctuation ≤ 300 kW.

Images