A gas turbine combustor gas-liquid dual fuel mixed combustion test system and a working method thereof

Abstract

The present application relates to the field of gas turbine, in particular to a gas turbine combustion chamber gas-liquid dual fuel mixed combustion test system and working method thereof, comprising: a combustion cavity unit, a combustion state monitoring unit, a liquid fuel supply unit, a gas fuel supply unit, a main air supply unit and a central control unit; the combustion cavity unit comprises a test shell, a flame tube, a dual fuel nozzle and an igniter, the flame tube is installed in the inner cavity of the test shell and is fixed by the head and tail support. The present application sets up a test system by setting a dual fuel nozzle and a flame tube in a unique test shell, and configuring an igniter, a pressure pulsation sensor and other structures, combined with a central control computer to ensure that the combustion chamber outlet temperature remains unchanged, through precise control of the gas fuel and liquid fuel flow, the dual fuel mixed combustion characteristic curve under each working condition is automatically obtained.

Description

Technical Field

[0001] This invention relates to the field of gas turbines, and more specifically to a gas turbine combustion chamber gas-liquid dual-fuel co-firing test system and its working method. Background Technology

[0002] Dual-fuel gas turbines offer advantages such as multi-fuel compatibility, high power density, rapid start-up, and good maintainability, making them widely used in marine engineering, distributed energy generation, and fuel gas pipeline drives. The gaseous fuels used are typically natural gas, liquefied petroleum gas, hydrogen, and ammonia, while the liquid fuels are typically diesel, aviation kerosene, and methanol. The operation of dual-fuel gas turbines involves online switching between gaseous and liquid fuels. Currently, the commonly used method of calculating the target fuel quantity based on the calorific value can generally achieve switching between two fuels within a specified time. However, this method suffers from inaccurate initial target fuel quantities, leading to significant fluctuations in turbine speed and gas turbine output power—a problem known as poor dual-fuel switching stability. This instability hinders the design and finalization of new dual-fuel gas turbines and can cause grid fluctuations, which is unacceptable to users, especially when dual-fuel switching is frequent. Therefore, poor dual-fuel switching stability is one of the main technical bottlenecks currently limiting the rapid design and further widespread application of dual-fuel gas turbines.

[0003] The dual-fuel switching process is essentially a superposition of multiple operating states of mixed combustion of gaseous and liquid fuels. Poor stability during dual-fuel switching is primarily due to significant fluctuations in the combustion chamber outlet temperature during the mixed combustion of gaseous and liquid fuels. During dual-fuel switching, given an inaccurate initial target fuel quantity, corrections must be made within a very short time using the fuel flow rate change rate. This often results in adjustments to gas turbine control parameters within a large range, leading to significant power fluctuations and prolonged or even exceeded switching completion times. Even highly precise fuel switching control strategies cannot effectively reduce power fluctuations and thus control dual-fuel switching stability. This is mainly because different operating conditions, such as varying heat dissipation, initial fuel operating states, and combustion efficiencies, make it difficult to maintain combustion chamber outlet temperature stability simply by using the method of converting the target fuel flow rate to equal calorific value. Therefore, there is an urgent need to develop a test system and its operating method that can improve the combustion stability of the gas-liquid fuel mixed combustion process, thereby maintaining high efficiency and stability of combustion during dual-fuel switching in gas turbines, reducing turbine speed and power fluctuations during the process, and ensuring successful online dual-fuel switching within specified timeframes. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a gas turbine combustor gas-liquid dual-fuel co-firing test system and its working method.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a gas turbine combustion chamber gas-liquid dual-fuel co-firing test system, comprising: a combustion chamber unit, a combustion state monitoring unit, a liquid fuel supply unit, a gas fuel supply unit, a main air supply unit, and a central control unit; The combustion chamber unit includes a test shell, a flame tube, a dual-fuel nozzle, and an igniter. The flame tube is installed in the internal cavity of the test shell and is fixed by head and tail supports. The dual-fuel nozzle is fixed to the nozzle mounting slope of the test shell and the injection end of the dual-fuel nozzle extends into the combustion chamber of the flame tube. The igniter is fixed to the surface of the upper cover plate of the test shell and the ignition end of the igniter is inserted into the flame tube inlet of the flame tube. The combustion state monitoring unit includes a pressure pulsation sensor, a first total temperature probe, a second total temperature probe, a third total temperature probe, a fourth total temperature probe, and a fifth total temperature probe. The first total temperature probe, the second total temperature probe, the third total temperature probe, the fourth total temperature probe, and the fifth total temperature probe are all installed in the exhaust section of the test housing. The pressure pulsation sensor is fixed to the surface of the upper cover plate of the test housing, and the probe axis of the pressure pulsation sensor is coaxial with the center line of the main combustion hole of the flame tube. The liquid fuel supply unit includes a liquid fuel system, the outlet of which is connected to the liquid fuel inlet pipe of the dual fuel nozzle. The gas fuel supply unit includes a gas fuel system, the outlet of which is connected to the gas fuel inlet pipe of the dual fuel nozzle.

[0006] In a preferred embodiment, it further includes: The main air supply unit includes a main air system, the main air outlet of the main air system is connected to the air inlet pipe of the test housing, and the gas outlet of the test housing is connected to the exhaust pipe of the main air system. The central control unit includes a central control computer, which is electrically connected to the igniter, the combustion status monitoring unit, the liquid fuel supply unit, the gas fuel supply unit, and the main air supply unit.

[0007] In a preferred embodiment, the test shell is a reflux-type shell structure with a fan-shaped cross-section. The test shell is integrally provided with a nozzle mounting slope, a top cover plate, an air inlet section, and an exhaust section. An air inlet is provided at the end of the air inlet section, and an exhaust section is provided at the end of the exhaust section. The flame tube is a near-cylindrical structure and is integrally formed by a left straight section and a right converging section. An ignition tube and a main combustion hole are provided on the side wall of the straight section of the flame tube, and an arc-shaped mounting seat is provided at the tail converging section of the flame tube.

[0008] In a preferred embodiment, the dual-fuel nozzle is provided with a first liquid fuel inlet, a second liquid fuel inlet, a first gas fuel inlet, a second gas fuel inlet, a connector, and a mounting flange. The connector of the dual-fuel nozzle is inserted into the central hole of the cyclone separator at the head of the flame tube, and the mounting flange is fixed to the nozzle mounting ramp of the test housing by fasteners.

[0009] In a preferred embodiment, the first total temperature probe, the second total temperature probe, the third total temperature probe, the fourth total temperature probe, and the fifth total temperature probe are uniformly installed circumferentially inside the exhaust section cavity of the test housing; The combustion status monitoring unit also includes a sampling probe and a flue gas analyzer. The sampling probe is installed inside the exhaust section cavity of the test housing. The outlet end of the sampling probe is connected to the inlet of the flue gas analyzer through an air duct. The flue gas analyzer is electrically connected to the central control computer. The liquid fuel system includes a first liquid fuel subsystem and a second liquid fuel subsystem that are independent of each other. The liquid fuel branch outlet of the first liquid fuel subsystem is connected to the first liquid fuel inlet pipe of the dual fuel nozzle, and the liquid fuel branch outlet of the second liquid fuel subsystem is connected to the second liquid fuel inlet pipe of the dual fuel nozzle.

[0010] In a preferred embodiment, the first liquid fuel subsystem includes a liquid fuel branch, a liquid fuel source, a liquid booster pump, a liquid filter, a liquid regulating valve, a liquid shut-off valve, a liquid mass flow meter, a liquid bypass valve, and a liquid check valve. The outlet of the liquid fuel source is connected in sequence to the liquid booster pump, liquid shut-off valve, liquid filter, liquid regulating valve, liquid mass flow meter, and liquid check valve before being connected to the outlet of the liquid fuel branch. The inlet end of the liquid bypass valve is connected to the pipeline between the liquid shut-off valve and the liquid filter, and the outlet end of the liquid bypass valve is connected to the vent. The second liquid fuel subsystem includes a liquid fuel branch, a liquid fuel source, a liquid booster pump, a liquid filter, a liquid regulating valve, a liquid shut-off valve, a liquid mass flow meter, a liquid bypass valve, and a liquid check valve. The outlet of the liquid fuel source is connected sequentially along the fuel flow direction to the liquid booster pump, the liquid shut-off valve, the liquid filter, the liquid regulating valve, the liquid mass flow meter, and the liquid check valve, and finally connected to the outlet of the liquid fuel branch. The inlet end of the liquid bypass valve is connected to the main pipeline between the liquid shut-off valve and the liquid filter, and the outlet end of the liquid bypass valve is connected to the fuel vent.

[0011] In a preferred embodiment, the gaseous fuel system includes a gaseous fuel source, a first shut-off valve, a filter, a water bath heater, a bypass valve, and a gaseous fuel main line. The outlet of the gaseous fuel source is connected sequentially to the first shut-off valve, the filter, and the water bath heater along the fuel flow direction before entering the gaseous fuel main line. The inlet end of the bypass valve is connected to the main pipeline between the water bath heater and the gaseous fuel main line, and the outlet end of the bypass valve is connected to the fuel vent. The gaseous fuel main line is divided into four independent branches downstream of the water bath heater, namely, gaseous fuel branch one, gaseous fuel branch two, gaseous fuel branch three, and gaseous fuel branch four.

[0012] In a preferred embodiment, the gaseous fuel branch line is connected in series with a second shut-off valve, a first regulating valve, a mass flow meter, and a first check valve along the fuel flow direction, and the outlet of the gaseous fuel branch line is connected to the first gaseous fuel inlet pipeline of the dual fuel nozzle. The second gas fuel branch is connected in series with a third shut-off valve, a second regulating valve, a second mass flow meter, and a second check valve along the fuel flow direction. The outlet of the second gas fuel branch is connected to the second gas fuel inlet pipeline of the dual fuel nozzle. The three gas fuel branches are connected in series with the fourth shut-off valve, the third regulating valve, the third mass flow meter, and the third check valve along the fuel flow direction. The outlet of the three gas fuel branches is connected to the main pipeline downstream of the liquid fuel check valve and upstream of the first liquid fuel inlet of the dual fuel nozzle. The four gas fuel branches are connected in series along the fuel flow direction, consisting of a fifth shut-off valve, a fourth regulating valve, a fourth mass flow meter, and a fourth check valve. The outlet of the four gas fuel branches is connected to the main pipeline downstream of the liquid two-way check valve and upstream of the second liquid fuel inlet of the dual fuel nozzle.

[0013] In a preferred embodiment, the main air system includes a main air path, a main air source, a heater, a bypass valve, a regulating valve, a mass flow meter, a pressure sensor, and a temperature sensor; The outlet of the main air source is connected to the heater, regulating valve, and mass flow meter in sequence along the airflow direction and then connected to the outlet of the main air path. The inlet end of the bypass valve is connected to the main pipeline between the heater and the regulating valve, and the outlet end of the bypass valve is connected to the air vent. Both the pressure sensor and the temperature sensor are installed on the main pipeline between the mass flow meter and the air inlet on the main air line. The heater, bypass valve, and regulating valve are all connected to the central control computer via signal transmission, as are the mass flow meter, pressure sensor, and temperature sensor.

[0014] The present invention also provides a method for operating a gas turbine combustor gas-liquid dual-fuel co-firing test system, comprising the following steps: S1. Ignition preparation and combustion chamber ignition: The main air system is started by controlling the central control computer, adjusting the temperature, pressure and flow rate of the main air to the required values ​​for ignition conditions and maintaining stability, controlling the igniter to start, and simultaneously controlling the liquid fuel system to supply liquid fuel according to the preset mode to complete the successful ignition of the combustion chamber. S2. Stable target operating conditions: The main air temperature, pressure, and flow parameters of the main air system are adjusted by the central control computer, and the liquid fuel supply parameters of the liquid fuel system are adjusted synchronously to the target operating conditions, so that the combustion chamber can stably burn in the full liquid fuel mode, and at the same time, the gas supply parameters of the gas fuel system are pre-adjusted and prepared. S3. Liquid-to-Gas Dual-Fuel Co-firing Test: Taking the current stable operating time of all liquid fuel as time t0, the central control computer collects the detection data from the first to the fifth total temperature probes, calculates and determines the average temperature at the combustion chamber outlet at time t0 as the target stable temperature, and presets the allowable temperature fluctuation range and the combustion chamber pressure pulsation limit value; taking the total liquid fuel flow rate at time t0 as the initial value, the liquid fuel supply is gradually reduced and the gas fuel supply is correspondingly increased according to the set step size until the liquid fuel flow rate drops to a certain level. During the test, the central control computer records the fuel flow rate data, real-time combustion chamber outlet temperature, and measured pressure pulsation data at each steady-state co-firing operating point in real time; S4. Safety and stability determination of the liquid-to-gas conversion process: During the liquid-to-gas co-firing test, the central control computer executes over-limit logic judgment in real time. If the real-time average temperature at the combustion chamber outlet exceeds the preset allowable fluctuation range, or the measured value of pressure pulsation exceeds the preset limit, the test is immediately interrupted and reset to the stable working state of all-liquid fuel at time t0. The steps are then re-executed after reducing the fuel flow change step size. If the real-time average temperature at the combustion chamber outlet does not exceed the allowable fluctuation range and the measured value of pressure pulsation does not exceed the limit, the liquid-to-gas co-firing test continues to be completed. S5. Plotting the liquid-to-gas co-firing characteristic curve; After the liquid-to-gas co-firing test is completed, the central control computer shuts down the liquid fuel system and maintains the combustion chamber in stable operation in full gas fuel mode. Based on the recorded data of each steady-state co-firing working point, the conversion coefficient between the change in liquid fuel flow rate and the change in gas fuel flow rate at each working point is calculated, and the liquid-gas co-firing characteristic curve LG under this working condition is plotted. S6. Gas-to-liquid dual-fuel co-firing test: Taking the current stable working time of all gas fuel as the new t0 time, the average temperature of the combustion chamber outlet at this time is determined by the central control computer as the target stable temperature. Taking the total gas fuel flow rate at t0 time as the initial value, the gas fuel supply is gradually reduced and the liquid fuel supply is correspondingly increased according to the set step size until the gas fuel flow rate drops to the minimum. During the test, the fuel flow rate data, real-time temperature of the combustion chamber outlet, and measured pressure pulsation data of each steady-state co-firing working point are recorded in real time by the central control computer. S7. Safety and stability determination of the gas-to-liquid conversion process; During the gas-to-liquid co-firing test, the central control computer executes over-limit logic judgment in real time. If the real-time average temperature at the combustion chamber outlet exceeds the preset allowable fluctuation range, or the measured value of pressure pulsation exceeds the preset limit, the test is immediately interrupted, reset to the stable working state of all gas fuel at the current time t, and the steps are re-executed after reducing the fuel flow change step size. If the real-time average temperature at the combustion chamber outlet does not exceed the allowable fluctuation range and the measured value of pressure pulsation does not exceed the limit, the gas-to-liquid co-firing test continues to be completed. S8. Plotting the gas-liquid co-firing characteristic curve; After the gas-liquid co-firing test is completed, the central control computer shuts down the gas fuel system and maintains the combustion chamber in stable operation in full liquid fuel mode. Based on the recorded data of each steady-state co-firing working point, the conversion coefficient between the change in gas fuel flow rate and the change in liquid fuel flow rate at each working point is calculated, and the gas-liquid co-firing characteristic curve GL under this working condition is plotted. S9. Establishment of a database of co-firing characteristics under all operating conditions: Adjust the test conditions through the central control computer, repeat the steps until all target operating conditions are met, complete the liquid-gas and gas-liquid bidirectional co-firing tests, obtain the conversion coefficient of the flow rate change of bidirectional fuel switching under all operating conditions, and finally establish a database of dual-fuel co-firing characteristic curves under all operating conditions in the combustion chamber.

[0015] The beneficial effects of this invention are as follows: By setting up a dual-fuel nozzle and flame tube in an independent test housing, and configuring an igniter, pressure pulsation sensor, total temperature probe, sampling probe, flue gas analyzer, liquid fuel system, main air system and gas fuel system as the test system, combined with a central control computer to ensure that the combustion chamber outlet temperature remains constant, the dual-fuel co-firing characteristic curve under each working condition is automatically obtained by precisely controlling the flow rate of gas fuel and liquid fuel. The optimal relative fuel change ratio of this type of combustion chamber under all working conditions is obtained accurately and reliably. High-precision parameter values ​​of all working conditions within a wide parameter range can be obtained with relatively small work input. The dual-fuel switching test of the whole machine is fully technically understood, reducing uncertainty and significantly reducing the development investment and test cost of the combustion chamber. The design fully considers the fluctuations in output power and turbine speed during dual-fuel switching of gas turbines. Under the condition of precise control of combustion chamber outlet temperature, flame stability is monitored by pressure pulsation measurement to determine the target fuel flow rate. This significantly reduces the power fluctuations caused by fuel changes determined by the equal calorific value method, and solves the dilemma of difficult design finalization of dual-fuel combustion chambers for gas turbines and the lack of scientific test systems and working methods. The experimental system is simple and its operating method is clear. It can be extended to the development of gas turbines using gas-gas dual-fuel or liquid-liquid dual-fuel systems with different calorific values. This enables more stable power output during the switching between any two fuels, providing strong technical support for the design and finalization of new dual-fuel combustors for gas turbines, and has high application value. Moreover, it allows for multiple fuel branches for a single fuel, broadening its application range and meeting the future development needs of low-emission combustors, thus strongly supporting the development of stable dual-fuel switching technology for gas turbines. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the working method of the present invention; Figure 3 This is a schematic diagram of the co-firing characteristics of Ne1 liquid fuel converted into gaseous fuel.

[0017] In the diagram: 1. Test housing; 1-3. Nozzle mounting ramp; 1-5. Top cover; 1-6. Air inlet section; 1-6A. Air inlet; 1-7. Exhaust section; 1-7A. Gas outlet; 2. Flame tube; 3. Dual-fuel nozzle; 3-1. First liquid fuel inlet; 3-2. Second liquid fuel inlet; 3-3. First gaseous fuel inlet; 3-4. Second gaseous fuel inlet; 4. Igniter; 5. Pressure pulsation sensor; 6-1. First total temperature probe; 6-2. Second total temperature probe; 6-3. Third total temperature probe; 6-4. Fourth total temperature probe; 6-5. Fifth total temperature probe; 7. Sampling probe 8. Flue gas analyzer; 9. Central control computer; AB. Liquid fuel system; A. First liquid fuel subsystem; A0. Liquid fuel branch line; A1. Liquid fuel source for branch line; A2. Liquid booster pump for branch line; A3. Liquid filter for branch line; A4. Liquid regulating valve for branch line; A5. Liquid shut-off valve for branch line; A6. Liquid mass flow meter for branch line; A7. Liquid bypass valve for branch line; A8. Liquid check valve for branch line; B. Second liquid fuel subsystem; B0. Liquid fuel branch line 2; B1. Liquid fuel source for branch line 2; B2. Liquid booster pump for branch line 2; B3. Liquid filter for branch line 2; B4. Liquid regulating valve for branch line 2; B 5. Liquid two-way shut-off valve; B6. Liquid two-way mass flow meter; B7. Liquid two-way bypass valve; B8. Liquid two-way check valve; C. Gas fuel system; C0. Gas fuel main line; C0-1. Gas fuel branch line; C0-2. Gas fuel branch line 2; C0-3. Gas fuel branch line 3; C0-4. Gas fuel branch line 4; C1. Gas fuel source; C2. Water bath heater; C3. Filter; C4-1. First regulating valve; C4-2. Second regulating valve; C4-3. Third regulating valve; C4-4. Fourth regulating valve; C5. First shut-off valve; C5-1. Second shut-off valve; C5- 2. Third shut-off valve; C5-3. Fourth shut-off valve; C5-4. Fifth shut-off valve; C6-1. Mass flow meter; C6-2. Second mass flow meter; C6-3. Third mass flow meter; C6-4. Fourth mass flow meter; C7. Second bypass valve; C8-1. First check valve; C8-2. Second check valve; C8-3. Third check valve; C8-4. Fourth check valve; K. Main air system; K0. Main air path; K1. Main air source; K2. Heater; K3. First bypass valve; K4. Regulating valve; K6. Mass flow meter; K9. Pressure sensor; K10. Temperature sensor. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] As attached Figure 1-3 As shown, this embodiment provides a gas turbine combustor gas-liquid dual-fuel co-firing test system, including a combustion chamber unit, a combustion state monitoring unit, a liquid fuel supply unit, a gas fuel supply unit, a main air supply unit, and a central control unit.

[0020] The combustion chamber unit is the core carrier of combustion in the combustion chamber, comprising a test housing 1, a flame tube 2, a dual-fuel nozzle 3, and an igniter 4. The test housing 1 is a fan-shaped annular reflux shell structure, made of high-temperature resistant alloy material, and integrally formed with a nozzle mounting ramp 1-3, an upper cover plate 1-5, an air inlet section 1-6, and an exhaust section 1-7. The air inlet section 1-6 has an air inlet 1-6A at its end for receiving combustion air, and the exhaust section 1-7 has a gas outlet 1-7A at its end for discharging combusted gas. The housing contains a flame tube mounting support structure and also provides mounting interfaces for sensors and probes. All interfaces are sealed to ensure the airtightness of the chamber.

[0021] The flame tube 2 has a near-cylindrical structure, welded from high-temperature alloy plates. It consists of a straight section on the left and a contracting section on the right, and is installed as a whole in the internal cavity of the test shell 1. It is fixedly connected to the inner wall of the test shell 1 through a head locator and a tail arc-shaped mounting seat, and a thermal expansion gap is reserved to allow free expansion at high temperatures. A vortex generator is welded to the left head of the flame tube 2 to achieve air and fuel mixing and flame stabilization. The side wall of the straight section is provided with a flame ignition tube and multiple sets of main combustion holes and mixing holes. The main combustion holes are used to introduce main combustion air and also serve as observation windows for pressure pulsation detection. The flame ignition tube is used to connect to the ignition end of the igniter 4. The tail contracting section is provided with an arc-shaped mounting seat for installation and thermal expansion displacement compensation.

[0022] The dual-fuel nozzle 3 is a centrifugal nozzle that can be used for both liquid and gas fuel atomization and gas fuel injection. It is equipped with a first liquid fuel inlet 3-1, a second liquid fuel inlet 3-2, a first gas fuel inlet 3-3, a second gas fuel inlet 3-4, a connector, and a mounting flange. The connector is inserted into the center hole of the cyclone separator at the head of the flame tube 2, and the injection end extends into the combustion chamber of the flame tube 2. The mounting flange is fixed to the nozzle mounting ramp 1-3 of the test housing 1 with high-strength bolts. A metal sealing gasket is provided between the flange and the ramp to ensure airtight connection. The two liquid fuel inlets and the two gas fuel inlets are independent of each other, which can realize the independent supply of single or multiple fuels to meet the combustion requirements of different working conditions.

[0023] Igniter 4 is a high-energy electric spark igniter. The main body is fixedly installed on the surface of the upper cover plate 1-5 of the test housing 1 by bolts. The ignition end and the discharge end are correspondingly inserted into the inlet of the flame tube 2. Ignition can be started and stopped under the control of the central control computer 9, providing a reliable ignition source for combustion chamber ignition.

[0024] The combustion status monitoring unit is used to collect combustion status parameters of the combustion chamber in real time, including pressure pulsation sensor 5, first total temperature probe 6-1, second total temperature probe 6-2, third total temperature probe 6-3, fourth total temperature probe 6-4, fifth total temperature probe 6-5, sampling probe 7, and flue gas analyzer 8.

[0025] The pressure pulsation sensor 5 is a high-frequency piezoelectric pressure sensor. The main body is fixedly installed on the surface of the upper cover plate 1-5 of the test housing 1 by threads. The probe axis of the sensor is coaxial with the center line of the main combustion hole of the flame tube 2. The probe end extends into the interior of the test housing 1 and faces the main combustion hole of the flame tube 2. It can detect the combustion pressure pulsation signal inside the flame tube 2 in real time. The signal is transmitted to the central control computer 9 through a shielded cable for judging the flame stability.

[0026] The first total temperature probe 6-1, the second total temperature probe 6-2, the third total temperature probe 6-3, the fourth total temperature probe 6-4, and the fifth total temperature probe 6-5 are all uniformly installed circumferentially inside the exhaust section 1-7 cavity of the test housing 1. The sensing end of the probe is directly downstream of the fan-shaped cross-section outlet of the flame tube 2, and can collect the gas temperature data at different positions of the combustion chamber outlet in real time. The data is transmitted to the central control computer 9 through a shielded cable, and the central control computer 9 calculates the real-time average temperature of the combustion chamber outlet.

[0027] The sampling probe 7 is a stainless steel flue gas sampling probe, which is installed inside the exhaust section 1-7 chamber of the test housing 1, and is on the same cross section as the five total temperature probes. The sampling port is directly facing the direction of the gas flow. The outlet end of the sampling probe 7 is connected to the inlet of the flue gas analyzer 8 through a heated air tracing pipe. It can extract the gas sample from the combustion chamber outlet and transport it to the flue gas analyzer 8 to prevent water vapor in the flue gas from condensing.

[0028] The flue gas analyzer 8 is an infrared flue gas analyzer that can detect the concentration of flue gas components. By being electrically connected to the central control computer 9, the detected flue gas emission data can be transmitted to the central control computer 9 in real time for storage and analysis, and is used to monitor combustion efficiency and emission characteristics.

[0029] The liquid fuel supply unit is used to provide the combustion chamber with liquid fuel with precise and controllable flow rate. It includes a liquid fuel system AB, which includes a first liquid fuel subsystem A and a second liquid fuel subsystem B, which are independent of each other. The two subsystems have completely identical structures and can work independently or simultaneously to meet the fuel supply requirements of different operating conditions.

[0030] The first liquid fuel subsystem A includes a liquid fuel branch line A0, a liquid fuel source A1, a liquid booster pump A2, a liquid filter A3, a liquid regulating valve A4, a liquid shut-off valve A5, a liquid mass flow meter A6, a liquid bypass valve A7, and a liquid check valve A8.

[0031] In some other specific embodiments, the outlet of the liquid fuel source A1 is connected sequentially along the fuel flow direction to the liquid booster pump A2, the liquid shut-off valve A5, the liquid filter A3, the liquid regulating valve A4, the liquid mass flow meter A6, and the liquid check valve A8 via a stainless steel high-pressure pipeline, and finally connected to the outlet of the liquid fuel branch line A0. The outlet pipeline of the liquid fuel branch line A0 is connected to the first liquid fuel inlet 3-1 of the dual fuel nozzle 3. The inlet end pipeline of the liquid bypass valve A7 is connected to the main pipeline between the liquid shut-off valve A5 and the liquid filter A3, and the outlet end is connected to the fuel vent, forming an independent venting channel.

[0032] The liquid booster pump A2, liquid regulating valve A4, liquid shut-off valve A5, and liquid bypass valve A7 are all electrically connected to the central control computer 9 via control cables to receive control commands and complete the action adjustment; the liquid mass flow meter A6 is electrically connected to the central control computer 9 via a signal cable to provide real-time feedback of fuel flow data.

[0033] The second liquid fuel subsystem B includes a liquid fuel branch B0, a liquid fuel source B1, a liquid booster pump B2, a liquid filter B3, a liquid regulating valve B4, a liquid shut-off valve B5, a liquid mass flow meter B6, a liquid bypass valve B7, and a liquid check valve B8. Its pipeline connections, component parameters, and control connection methods are completely consistent with those of the first liquid fuel subsystem A. The outlet pipeline of the liquid fuel branch B0 is connected to the second liquid fuel inlet 3-2 of the dual fuel nozzle 3, which will not be described in detail here.

[0034] The gas fuel supply unit is used to provide the combustion chamber with gas fuel with precise and controllable flow rate. It includes a gas fuel system C, which includes a gas fuel source C1, a first shut-off valve C5, a filter C3, a water bath heater C2, a second bypass valve C7, and a gas fuel main line C0. The downstream of the gas fuel main line C0 is divided into four independent branches, namely gas fuel branch C0-1, gas fuel branch C0-2, gas fuel branch C0-3, and gas fuel branch C0-4.

[0035] In some other specific embodiments, the outlet of the gaseous fuel source C1 is connected to the first shut-off valve C5, filter C3, and water bath heater C2 in sequence through a stainless steel high-pressure pipeline along the fuel flow direction, and then connected to the gaseous fuel main line C0; the inlet end pipeline of the second bypass valve C7 is connected to the main pipeline between the water bath heater C2 and the gaseous fuel main line C0, and the outlet end is connected to the fuel vent, forming the main line venting channel.

[0036] The specific connection relationships, component parameters, and control connections of the four branch circuits are as follows: A gaseous fuel branch line C0-1 is connected in series with a second shut-off valve C5-1, a first regulating valve C4-1, a mass flow meter C6-1, and a first check valve C8-1 along the fuel flow direction. The branch line outlet is connected to the first gaseous fuel inlet 3-3 pipeline of the dual fuel nozzle 3, which is the first main gas supply branch line.

[0037] The second gas fuel branch C0-2 is connected in series with the third shut-off valve C5-2, the second regulating valve C4-2, the second mass flow meter C6-2, and the second check valve C8-2 along the fuel flow direction. The branch outlet is connected to the second gas fuel inlet 3-4 pipeline of the dual fuel nozzle 3, which is the second main gas supply branch.

[0038] The gas fuel branch C0-3 consists of a fourth shut-off valve C5-3, a third regulating valve C4-3, a third mass flow meter C6-3, and a third check valve C8-3 connected in series along the fuel flow direction. The branch outlet is connected to the main pipeline downstream of the liquid fuel check valve A8 and upstream of the first liquid fuel inlet 3-1 of the dual fuel nozzle 3. This is the first auxiliary gas supply branch, which can be used for pipeline purging and auxiliary combustion stabilization.

[0039] The gaseous fuel branch C0-4 is connected in series with the fifth shut-off valve C5-4, the fourth regulating valve C4-4, the fourth mass flow meter C6-4, and the fourth check valve C8-4 along the fuel flow direction. The branch outlet is connected to the main pipeline downstream of the liquid two-way check valve B8 and upstream of the second liquid fuel inlet 3-2 of the dual fuel nozzle 3, which is the second auxiliary gas supply branch.

[0040] The main air supply unit is used to provide combustion air with precise and controllable temperature, pressure, and flow rate to the combustion chamber. It includes a main air system K, which includes a main air path K0, a main air source K1, a heater K2, a first bypass valve K3, a regulating valve K4, a mass flow meter K6, a pressure sensor K9, and a temperature sensor K10.

[0041] In some other specific embodiments, the outlet of the main air source K1, along the airflow direction, is connected sequentially through a pipeline to a heater K2, a regulating valve K4, and a mass flow meter K6 before being connected to the outlet of the main air path K0. The outlet pipeline of the main air path K0 is connected to the air inlet 1-6A of the test housing 1, and the gas outlet 1-7A of the test housing 1 is connected to the exhaust pipeline of the main air system K, ultimately connecting to the exhaust gas treatment system. The inlet pipeline of the first bypass valve K3 is connected to the main pipeline between the heater K2 and the regulating valve K4, and the outlet is connected to the air vent, forming a bypass venting channel. The pressure sensor K9 and the temperature sensor K10 are both installed on the main pipeline between the mass flow meter K6 and the air inlet 1-6A on the main air path K0, respectively, for real-time detection of the air pressure and temperature entering the combustion chamber.

[0042] The heater K2, the first bypass valve K3, and the regulating valve K4 are all electrically connected to the central control computer 9 via control cables to receive control commands and complete parameter adjustments; the mass flow meter K6, the pressure sensor K9, and the temperature sensor K10 are all electrically connected to the central control computer 9 via signal cables to provide real-time feedback of air parameter data.

[0043] The central control unit is the core control and data processing unit of the test system, including the central control computer 9. The central control computer 9 is an industrial control computer, equipped with analog input / output modules, digital input / output modules, and communication modules. It is electrically connected to all the sensing elements of the igniter 4, the combustion status monitoring unit, the liquid fuel supply unit, the gas fuel supply unit, and the main air supply unit, respectively.

[0044] This application also provides a method for operating a gas turbine combustor gas-liquid dual-fuel co-firing test system, including the following steps: S1. Ignition preparation and combustion chamber ignition: The main air system K is started by the central control computer 9, so that the main air source K1, regulating valve K4 and first bypass valve K3 start working, adjust the temperature, pressure and flow of the main air to the required values ​​for ignition conditions and maintain stability, use heater K2 to heat the main air, use temperature sensor K10, pressure sensor K9 and mass flow meter K6 to measure relevant parameter values, control the start of igniter 4, and simultaneously control the liquid fuel system AB to supply liquid fuel according to the preset mode, and complete the successful ignition of the combustion chamber. S2. Target operating condition is stable; the main air temperature, pressure and flow parameters of the main air system K are adjusted by the central control computer 9, and the liquid fuel supply parameters of the liquid fuel system AB are adjusted to the target operating condition to make the combustion chamber burn stably in the full liquid fuel mode, while completing the pre-adjustment and preparation of the gas supply parameters of the gas fuel system C. S3. Liquid-to-Gas Dual-Fuel Co-firing Test: Taking the current stable operating time of all liquid fuel as time t0, the central control computer 9 collects the detection data from the first total temperature probe 6-1 to the fifth total temperature probe 6-5, calculates and determines the average temperature T30 at the combustion chamber outlet at time t0 as the target stable temperature, and presets the allowable temperature fluctuation range and the combustion chamber pressure pulsation limit value; taking the total liquid fuel flow rate at time t0 as the initial value, the liquid fuel supply is gradually reduced and the gas fuel supply is correspondingly increased according to the set step size until the liquid fuel flow rate drops to 0. During the test, the central control computer 9 records the fuel flow rate data, real-time combustion chamber outlet temperature, and measured pressure pulsation data at each steady-state co-firing operating point in real time; Specifically, S3, through the central control computer 9, clicks to start the co-firing test, and this moment is recorded as time t0. At this time, the central control computer 9 begins to monitor the measured value RMS of the combustion chamber pressure pulsation sensor 5 in real time. 实测 And through the downstream of the combustion chamber outlet (i.e., downstream of the fan-shaped section outlet of flame tube 2, such as...) Figure 1 (As shown in the H-direction view) Five total temperature probes were installed to collect the average combustion chamber outlet temperature T30 at time t0. This average temperature was used as the target temperature for maintaining a stable average combustion chamber outlet temperature. Before the test, the allowable fluctuation range was set to ±ΔT, meaning the test objective was to maintain the real-time average combustion chamber outlet temperature T30 during the dual-fuel co-firing process. 实测 Within the range of T30±ΔT, and RMS 实测 ≤RMS 限定 To demonstrate good flame stability, under the target experimental conditions, the liquid fuel flow rate FL0 at the initial time t0 of the current operating condition was used as the initial value. The flow rate was then gradually reduced according to a step size KL (the change in liquid fuel flow rate ΔFL, the reduction compared to the previous steady-state co-firing point), with corresponding increases in gaseous fuel, until the actual liquid fuel flow rate FL... 实测To reduce the number of steady-state co-firing operating points to 0, during this process, the number of steady-state co-firing operating points is set to nL. For each steady-state co-firing operating point, the central control computer records the values ​​of each parameter (including the measured flow rate of liquid fuel FL) through the central control computer. 实测 Liquid fuel flow rate change ΔFL (i.e., step size KL), gaseous fuel flow rate change ΔFG, and measured pressure pulsation value RMS. 实测 Real-time average temperature T3 at the combustion chamber outlet 实测 Other monitoring parameters), where the initial all-liquid fuel operating point (i.e., time t0) and the all-gaseous fuel operating point after co-firing (referred to as time tL) are each recorded as one steady-state co-firing operating point; S4. Safety and stability determination of the liquid-to-gas conversion process; During the liquid-to-gas co-firing test, the central control computer 9 executes over-limit logic determination in real time. If the real-time average temperature at the combustion chamber outlet exceeds the preset allowable fluctuation range, or the measured value of pressure pulsation exceeds the preset limit, the test is immediately interrupted and reset to the stable working state of all-liquid fuel at time t0. After reducing the fuel flow change step size, step S3 is executed again. If the real-time average temperature at the combustion chamber outlet does not exceed the allowable fluctuation range and the measured value of pressure pulsation does not exceed the limit, the liquid-to-gas co-firing test is completed. Specifically, during the co-firing test (i.e., from time t0 to tL in step S3), the real-time average temperature T3 at the combustion chamber outlet is... 实测 When the temperature exceeds the required limit range T30±△T or the measured RMS value of combustion chamber pressure pulsation. 实测 If the conditions exceed the limits (i.e., the actual temperature exceeds the limit or the temperature exceeds the limit due to flame fluctuations predicted by the flame stability), the co-firing test is interrupted, the state is reset to the new t0 time state, the step size KL value is reduced, and the test is carried out again according to step S3. During the co-firing test (i.e., from time t0 to tL in step S3), the real-time average temperature T3 at the combustion chamber outlet is... 实测 The temperature limit T30±△T was not exceeded and the measured value of combustion chamber pressure pulsation RMS was not exceeded. 实测 If the conditions do not exceed the limits (i.e., there is no risk of actual temperature exceeding the limit or temperature exceeding the limit due to flame fluctuations), then proceed to the next step of the test; S5. Plotting the liquid-to-gas co-firing characteristic curve; After the liquid-to-gas co-firing test is completed, the central control computer 9 controls the shutdown of the liquid fuel system AB, maintains the combustion chamber in stable operation in the all-gas fuel mode, and calculates the conversion coefficient between the change in liquid fuel flow rate and the change in gas fuel flow rate at each working point based on the recorded data of each steady-state co-firing working point, and plots the liquid-gas co-firing characteristic curve LG under this working condition. Specifically, when the liquid fuel is completely converted to gaseous fuel, the liquid fuel is shut off, maintaining stable combustion chamber conditions and average combustion chamber outlet temperature. Using the parameters automatically recorded by the central control computer, the ratio of liquid to gaseous fuel flow rate changes at each steady-state co-firing point is calculated and stored. The test data is then organized according to a set mode. The percentage of real-time liquid fuel flow rate to initial liquid fuel flow rate is plotted on the x-axis, and the ratio of liquid fuel flow rate change ΔFL to gaseous fuel flow rate change ΔFG (e.g., in condition Ne1, the conversion coefficient is β-LG-Ne1) is plotted on the y-axis to create the dual-fuel co-firing characteristic curve LG under this liquid-to-gas conversion condition. (See diagram below.) Figure 3 As shown; S6. Gas-to-liquid dual-fuel co-firing test: Taking the current stable working time of all gas fuel as the new t0 time, the average temperature T30 of the combustion chamber outlet at this time is collected and determined by the central control computer 9 as the target stable temperature. Taking the total gas fuel flow rate at t0 time as the initial value, the gas fuel supply is gradually reduced and the liquid fuel supply is correspondingly increased according to the set step size until the gas fuel flow rate drops to 0. During the test, the fuel flow rate data, real-time temperature of the combustion chamber outlet, and measured pressure pulsation data of each steady-state co-firing working point are recorded in real time by the central control computer 9. S7. Safety and stability determination of the gas-to-liquid process; During the gas-to-liquid co-firing test, the central control computer 9 executes over-limit logic determination in real time. If the real-time average temperature at the combustion chamber outlet exceeds the preset allowable fluctuation range, or the measured value of pressure pulsation exceeds the preset limit, the test is immediately interrupted and reset to the stable working state of all gas fuel at the current time t0. After reducing the fuel flow change step size, step S6 is executed again. If the real-time average temperature at the combustion chamber outlet does not exceed the allowable fluctuation range and the measured value of pressure pulsation does not exceed the limit, the gas-to-liquid co-firing test is completed. Specifically, during the co-firing test (i.e., from time t0 to tG in step S6), the real-time average temperature T3 at the combustion chamber outlet... 实测 When the temperature exceeds the required limit range T30±△T or the measured RMS value of combustion chamber pressure pulsation. 实测 If the conditions exceed the specified limits (i.e., the actual temperature exceeds the limit or the temperature exceeds the limit due to flame fluctuations predicted based on flame stability), the co-firing test is interrupted, reset to the new state at time t0, the step size KG is reduced, and the test is restarted according to step S6; during the co-firing test (i.e., from time t0 to time tG in step S6), the real-time average temperature T3 at the combustion chamber outlet is... 实测 The temperature limit T30±△T was not exceeded and the measured value of combustion chamber pressure pulsation RMS was not exceeded. 实测 If the conditions do not exceed the limits (i.e., there is no risk of actual temperature exceeding the limit or temperature exceeding the limit due to flame fluctuations), then proceed to the next step of the test; S8. Plotting the gas-to-liquid co-firing characteristic curve; After the gas-to-liquid co-firing test is completed, the central control computer 9 controls the shutdown of the gas fuel system C to maintain the combustion chamber in stable operation in the all-liquid fuel mode. Based on the recorded data of each steady-state co-firing working point, the conversion coefficient between the change in gas fuel flow rate and the change in liquid fuel flow rate at each working point is calculated, and the gas-liquid co-firing characteristic curve GL under this working condition is plotted. Specifically, when the gaseous fuel is completely converted to liquid fuel, the gaseous fuel is shut off, and the combustion chamber operating conditions and the average temperature at the combustion chamber outlet are kept stable. The central control computer automatically records the values ​​of various parameters, calculates the ratio of the change in gaseous and liquid fuel flow rates at each steady-state co-firing point, stores the data, and organizes the test data according to the set mode. The percentage of the real-time gaseous fuel flow rate to the initial gaseous fuel flow rate is used as the abscissa, and the ratio of the change in gaseous fuel flow rate ΔFG to the change in liquid fuel flow rate ΔFL (if the operating condition is Ne1, then the conversion coefficient β-GL-Ne1) is used as the ordinate to plot the dual-fuel co-firing characteristic curve GL under the gas-to-liquid state of this operating condition. S9. Establishment of a database of co-firing characteristics under all operating conditions: Adjust the test conditions through the central control computer 9, repeat steps S2 to S8, complete the liquid-gas and gas-liquid bidirectional co-firing tests under all target operating conditions, obtain the conversion coefficient of flow rate change under all operating conditions, and finally establish a database of dual-fuel co-firing characteristic curves under all operating conditions in the combustion chamber.

[0045] It should be noted that in step S1, the liquid fuel branch operates in a single liquid fuel branch A0 mode, using a relatively small nozzle to achieve good fuel atomization and help the combustion chamber ignite successfully.

[0046] In step S2, the liquid fuel branch operates in either a single liquid fuel branch A0 or both liquid fuel branch A0 and liquid fuel branch B0 operate simultaneously to maintain the target operating condition stability.

[0047] In step S3, the relationship between the number of dual-fuel steady-state co-firing operating points nL and the liquid fuel flow rate change step size KL (i.e., the liquid fuel flow rate change ΔFL) is KL=FL0 / (nL-1), and the selected initial value nL≥8 should be satisfied to ensure the test accuracy and the test results are reliable.

[0048] In step S5, the operation of the gas fuel is maintained. The operating mode may be that only one gas fuel branch C0-1 is working, or only one gas fuel branch C0-2 is working, or both gas fuel branches C0-1 and C0-2 are working simultaneously.

[0049] In step S6, the relationship between the number of dual-fuel steady-state co-firing operating points nG and the gas fuel flow rate change step size KG (i.e., gas fuel flow rate change ΔFG) is KG=FG0 / (nG-1), and the selected initial value nG≥8 should be satisfied to ensure experimental accuracy and reliable experimental results.

[0050] In steps S3 and S6, the absolute value of the combustion chamber outlet temperature fluctuation deviation range ΔT∈[0, 15℃] is set to ensure that the temperature fluctuation is within an acceptable range, and the combustion chamber pressure pulsation limit value RMS is set. 限定 The value is δ×Pair, where Pair is the main air pressure, and δ≤0.4%.

[0051] In step S1, the liquid fuel branch includes, but is not limited to, liquid fuel branch A0 and liquid fuel branch B0, and there may be more branches; in step S2, the gaseous fuel branch includes, but is not limited to, gaseous fuel branch C0-1 and gaseous fuel branch C0-2, and there may be more branches.

[0052] In step S1, selecting a suitable liquid fuel branch operating mode can flexibly switch to a suitable gas fuel operating mode, supplying gas fuel, and achieving successful combustion chamber ignition.

[0053] In steps S3 and S6, each steady-state co-firing operating point records other monitoring parameters through the central control computer 9, which may also include co-firing emission data obtained through sampling probe 7 and flue gas analyzer 8, providing data for monitoring low-emission status.

Claims

1. A gas turbine combustion chamber gas-liquid dual-fuel co-firing test system, characterized in that, include: Combustion chamber unit, combustion status monitoring unit, liquid fuel supply unit, gaseous fuel supply unit, main air supply unit, and central control unit; The combustion chamber unit includes a test housing (1), a flame tube (2), a dual-fuel nozzle (3), and an igniter (4). The flame tube (2) is installed in the internal cavity of the test housing (1) and is fixed by the head and tail. The dual-fuel nozzle (3) is fixed on the nozzle mounting slope (1-3) of the test housing (1) and the injection end of the dual-fuel nozzle (3) extends into the combustion chamber of the flame tube (2). The igniter (4) is fixed on the surface of the upper cover plate (1-5) of the test housing (1) and the ignition end of the igniter (4) is inserted into the flame tube inlet of the flame tube (2). The combustion state monitoring unit includes a pressure pulsation sensor (5), a first total temperature probe (6-1), a second total temperature probe (6-2), a third total temperature probe (6-3), a fourth total temperature probe (6-4), and a fifth total temperature probe (6-5). The first total temperature probe (6-1), the second total temperature probe (6-2), the third total temperature probe (6-3), the fourth total temperature probe (6-4), and the fifth total temperature probe (6-5) are all installed in the exhaust section (1-7) of the test housing (1). The pressure pulsation sensor (5) is fixed to the surface of the upper cover plate (1-5) of the test housing (1), and the probe axis of the pressure pulsation sensor (5) is coaxial with the center line of the main combustion hole of the flame tube (2). The liquid fuel supply unit includes a liquid fuel system (AB), the outlet of which is connected to the liquid fuel inlet pipe of the dual fuel nozzle (3), and the gas fuel supply unit includes a gas fuel system (C), the outlet of which is connected to the gas fuel inlet pipe of the dual fuel nozzle (3).

2. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 1, characterized in that, Also includes: The main air supply unit includes a main air system (K), the outlet of the main air path (K0) of the main air system (K) is connected to the air inlet (1-6A) pipe of the test housing (1), and the gas outlet (1-7A) of the test housing (1) is connected to the exhaust pipe of the main air system (K); The central control unit includes a central control computer (9), which is electrically connected to the igniter (4), the combustion status monitoring unit, the liquid fuel supply unit, the gas fuel supply unit, and the main air supply unit.

3. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 1, characterized in that, The test housing (1) is a reflux-type housing structure with a fan-shaped cross-section. The test housing (1) is integrally provided with a nozzle mounting slope (1-3), an upper cover plate (1-5), an air intake section (1-6), and an exhaust section (1-7). An air inlet (1-6A) is provided at the end of the air intake section (1-6), and an (1-7A) is provided at the end of the exhaust section (1-7). The flame tube (2) is a near-cylindrical structure and is integrally formed by a left straight section and a right converging section. An ignition tube and a main combustion hole are provided on the side wall of the straight section of the flame tube (2), and an arc-shaped mounting seat is provided at the tail converging section of the flame tube (2).

4. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 1, characterized in that, The dual-fuel nozzle (3) is provided with a first liquid fuel inlet (3-1), a second liquid fuel inlet (3-2), a first gas fuel inlet (3-3), a second gas fuel inlet (3-4), a connector and a mounting flange. The connector of the dual-fuel nozzle (3) is inserted into the center hole of the cyclone separator at the head of the flame tube (2). The mounting flange is fixed to the nozzle mounting ramp (1-3) of the test housing (1) by fasteners.

5. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 4, characterized in that, The first total temperature probe (6-1), the second total temperature probe (6-2), the third total temperature probe (6-3), the fourth total temperature probe (6-4), and the fifth total temperature probe (6-5) are uniformly installed circumferentially inside the exhaust section (1-7) cavity of the test housing (1); The combustion state monitoring unit also includes a sampling probe (7) and a flue gas analyzer (8). The sampling probe (7) is installed inside the exhaust section (1-7) cavity of the test housing (1). The outlet end of the sampling probe (7) is connected to the inlet of the flue gas analyzer (8) through an air inlet pipe. The flue gas analyzer (8) is electrically connected to the central control computer (9). The liquid fuel system (AB) includes a first liquid fuel subsystem (A) and a second liquid fuel subsystem (B) that are independent of each other. The outlet of the liquid fuel branch (A0) of the first liquid fuel subsystem (A) is connected to the first liquid fuel inlet (3-1) of the dual fuel nozzle (3), and the outlet of the liquid fuel branch (B0) of the second liquid fuel subsystem (B) is connected to the second liquid fuel inlet (3-2) of the dual fuel nozzle (3).

6. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 5, characterized in that, The first liquid fuel subsystem (A) includes a liquid fuel branch line (A0), a liquid fuel source (A1), a liquid booster pump (A2), a liquid filter (A3), a liquid regulating valve (A4), a liquid shut-off valve (A5), a liquid mass flow meter (A6), a liquid bypass valve (A7), and a liquid check valve (A8). The outlet of the liquid fuel source (A1) is connected in sequence to the liquid booster pump (A2), the liquid shut-off valve (A5), the liquid filter (A3), the liquid regulating valve (A4), the liquid mass flow meter (A6), and the liquid check valve (A8) before being connected to the outlet of the liquid fuel branch line (A0). The inlet end of the liquid bypass valve (A7) is connected to the pipeline between the liquid shut-off valve (A5) and the liquid filter (A3), and the outlet end of the liquid bypass valve (A7) is connected to the vent. The second liquid fuel subsystem (B) includes a liquid fuel branch (B0), a liquid fuel source (B1), a liquid booster pump (B2), a liquid filter (B3), a liquid regulating valve (B4), a liquid shut-off valve (B5), a liquid mass flow meter (B6), a liquid bypass valve (B7), and a liquid check valve (B8). The outlet of the liquid fuel source (B1) is connected sequentially along the fuel flow direction to the liquid booster pump (B2), the liquid shut-off valve (B5), the liquid filter (B3), the liquid regulating valve (B4), the liquid mass flow meter (B6), and the liquid check valve (B8), and finally connected to the outlet of the liquid fuel branch (B0). The inlet end of the liquid bypass valve (B7) is connected to the main pipeline between the liquid shut-off valve (B5) and the liquid filter (B3), and the outlet end of the liquid bypass valve (B7) is connected to the fuel vent.

7. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 2, characterized in that, The gas fuel system (C) includes a gas fuel source (C1), a first shut-off valve (C5), a filter (C3), a water bath heater (C2), a second bypass valve (C7), and a gas fuel main line (C0). The outlet of the gas fuel source (C1) is connected to the first shut-off valve (C5), the filter (C3), and the water bath heater (C2) in sequence along the fuel flow direction before entering the gas fuel main line (C0). The inlet end of the second bypass valve (C7) is connected to the main pipeline between the water bath heater (C2) and the gas fuel main line (C0). The outlet end of the second bypass valve (C7) is connected to the fuel vent. The gas fuel main line (C0) is divided into four independent branches downstream of the water bath heater (C2), namely, gas fuel branch 1 (C0-1), gas fuel branch 2 (C0-2), gas fuel branch 3 (C0-3), and gas fuel branch 4 (C0-4).

8. The gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 7, characterized in that, The gas fuel branch line (C0-1) is connected in series with the second shut-off valve (C5-1), the first regulating valve (C4-1), the mass flow meter (C6-1), and the first check valve (C8-1) along the fuel flow direction. The outlet of the gas fuel branch line (C0-1) is connected to the first gas fuel inlet (3-3) pipeline of the dual fuel nozzle (3). The gas fuel branch (C0-2) is connected in series with the third shut-off valve (C5-2), the second regulating valve (C4-2), the second mass flow meter (C6-2), and the second check valve (C8-2) along the fuel flow direction. The outlet of the gas fuel branch (C0-2) is connected to the second gas fuel inlet (3-4) pipeline of the dual fuel nozzle (3). The gas fuel three-branch line (C0-3) is connected in series with the fourth shut-off valve (C5-3), the third regulating valve (C4-3), the third mass flow meter (C6-3), and the third check valve (C8-3) along the fuel flow direction. The outlet of the gas fuel three-branch line (C0-3) is connected to the main pipeline downstream of the liquid one-branch check valve (A8) and upstream of the first liquid fuel inlet (3-1) of the dual fuel nozzle (3). The gas fuel four-branch (C0-4) is connected in series with the fifth shut-off valve (C5-4), the fourth regulating valve (C4-4), the fourth mass flow meter (C6-4), and the fourth check valve (C8-4) along the fuel flow direction. The outlet of the gas fuel four-branch (C0-4) is connected to the main pipeline downstream of the liquid two-way check valve (B8) and upstream of the second liquid fuel inlet (3-2) of the dual fuel nozzle (3).

9. A gas turbine combustor gas-liquid dual-fuel co-firing test system according to claim 2, characterized in that, The main air system (K) includes a main air path (K0), a main air source (K1), a heater (K2), a first bypass valve (K3), a regulating valve (K4), a mass flow meter (K6), a pressure sensor (K9), and a temperature sensor (K10). The outlet of the main air source (K1) is connected to the heater (K2), regulating valve (K4), and mass flow meter (K6) in sequence along the airflow direction, and then connected to the outlet of the main air path (K0). The inlet end of the first bypass valve (K3) is connected to the main pipeline between the heater (K2) and the regulating valve (K4), and the outlet end of the first bypass valve (K3) is connected to the air exhaust port. The pressure sensor (K9) and temperature sensor (K10) are both installed on the main air line (K0) between the mass flow meter (K6) and the air inlet (1-6A); The heater (K2), the first bypass valve (K3), and the regulating valve (K4) are all connected to the central control computer (9) via signal. The mass flow meter (K6), the pressure sensor (K9), and the temperature sensor (K10) are all connected to the central control computer (9) via signal.

10. A method for operating a gas turbine combustor gas-liquid dual-fuel co-firing test system, applied to a gas turbine combustor gas-liquid dual-fuel co-firing test system as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Ignition preparation and combustion chamber ignition; The central control computer (9) controls the start of the main air system (K), adjusts the temperature, pressure and flow rate of the main air to the required values ​​for ignition conditions and maintains stability, controls the start of the igniter (4), and simultaneously controls the liquid fuel system (AB) to supply liquid fuel according to the preset mode, thus completing the successful ignition of the combustion chamber; S2, target operating conditions are stable; adjust the main air temperature, pressure and flow parameters of the main air system (K) through the central control computer (9), and simultaneously adjust the liquid fuel supply parameters of the liquid fuel system (AB) to the target operating conditions, so that the combustion chamber can burn stably in the full liquid fuel mode, and at the same time complete the pre-adjustment and preparation of the gas supply parameters of the gas fuel system (C); S3, Liquid-to-Gas Dual-Fuel Co-firing Test: Taking the current stable working time of all liquid fuel as time t0, the detection data of the first total temperature probe (6-1) to the fifth total temperature probe (6-5) are collected by the central control computer (9), and the average temperature T30 of the combustion chamber outlet at time t0 is calculated and determined as the target stable temperature. The temperature fluctuation range and the pressure pulsation limit of the combustion chamber are preset. Taking the total flow rate of liquid fuel at time t0 as the initial value, the liquid fuel supply is gradually reduced and the gas fuel supply is correspondingly increased according to the set step size until the liquid fuel flow rate drops to 0. During the test, the fuel flow rate data, real-time temperature of the combustion chamber outlet, and measured pressure pulsation data of each steady-state co-firing working point are recorded in real time by the central control computer (9). S4. Safety and stability determination of liquid-to-gas process; During the liquid-to-gas co-firing test, the central control computer (9) performs over-limit logic determination in real time. If the real-time average temperature at the combustion chamber outlet exceeds the preset allowable fluctuation range, or the measured value of pressure pulsation exceeds the preset limit value, the test is immediately interrupted and reset to the stable working state of all liquid fuel at time t0. After reducing the fuel flow change step size, step S3 is executed again. If the real-time average temperature at the combustion chamber outlet does not exceed the allowable fluctuation range and the measured value of pressure pulsation does not exceed the limit value, the liquid-to-gas co-firing test is completed. S5. Plotting the liquid-to-gas co-firing characteristic curve; After the liquid-to-gas co-firing test is completed, the central control computer (9) controls the liquid fuel system (AB) to shut down and maintain the combustion chamber in stable operation under the full gas fuel mode. Based on the recorded data of each steady-state co-firing working point, the conversion coefficient between the change in liquid fuel flow rate and the change in gas fuel flow rate at each working point is calculated, and the liquid-gas co-firing characteristic curve LG under this working condition is plotted. S6. Gas-to-liquid dual-fuel co-firing test: The current stable working time of all gas fuel is taken as the new t0 time. The average temperature T30 of the combustion chamber outlet at the time is collected and determined by the central control computer (9) as the target stable temperature. The total gas fuel flow rate at t0 time is taken as the initial value. The gas fuel supply is gradually reduced and the liquid fuel supply is correspondingly increased according to the set step size until the gas fuel flow rate drops to 0. During the test, the fuel flow rate data, real-time temperature of the combustion chamber outlet, and measured data of pressure pulsation at each steady-state co-firing working point are recorded in real time by the central control computer (9). S7. Safety and stability assessment of the gas-to-liquid conversion process; During the gas-to-liquid co-firing test, the central control computer (9) performs over-limit logic judgment in real time. If the real-time average temperature at the combustion chamber outlet exceeds the preset allowable fluctuation range, or the measured value of pressure pulsation exceeds the preset limit, the test is immediately interrupted and reset to the stable working state of all gas fuel at the current time t0. After reducing the fuel flow change step size, step S6 is executed again. If the real-time average temperature at the combustion chamber outlet does not exceed the allowable fluctuation range and the measured value of pressure pulsation does not exceed the limit, the gas-to-liquid co-firing test is completed. S8. Plotting the gas-liquid co-firing characteristic curve; After the gas-liquid co-firing test is completed, the central control computer (9) controls the gas fuel system (C) to shut down and maintain the combustion chamber in a stable working mode under full liquid fuel. Based on the recorded data of each steady-state co-firing working point, the conversion coefficient between the change in gas fuel flow rate and the change in liquid fuel flow rate at each working point is calculated, and the gas-liquid co-firing characteristic curve GL under this working condition is plotted. S9. Establishment of a database of co-firing characteristics under all working conditions: Adjust the test conditions through the central control computer (9), repeat steps S2 to S8, complete the liquid-gas and gas-liquid bidirectional co-firing tests under all target working conditions, obtain the conversion coefficient of the flow rate change of bidirectional fuel switching under all working conditions, and finally establish a database of dual-fuel co-firing characteristic curves under all working conditions of the combustion chamber.

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