Method and system for preventing dry grinding and delaying self-stopping of standby engine of marine methanol fuel supply system

Abstract

The application provides a standby machine drainage dry grinding prevention and delay self-stopping control method and system of a marine methanol fuel supply system, aiming to solve the problems of high dry grinding risk of a methanol supply pump and long time idling of the system after stopping. After a standby machine command of the methanol machine is triggered, a drainage diaphragm pump and an initial drainage return valve are first started to establish a drainage cycle, the drainage diaphragm pump is stopped, the initial drainage return valve is closed and a stopping cycle return valve is started after liquid filling of a pipeline is completed, and then the methanol supply pump is started, a standby machine completion signal is fed back after a supply liquid pressure and medium temperature closed loop regulation reaches a pre-stopping machine condition; the cycle is maintained or delay self-stopping is performed according to a standby machine demand state during stopping. The standby machine, drainage, oil supply, stopping, cycle maintaining and delay self-stopping are integrated into a continuous state machine, and the safety, continuity and automation level of the methanol fuel supply system are improved.

Description

Technical Field

[0001] This invention relates to the field of marine methanol fuel supply control technology, and in particular to a backup engine diversion anti-dry grinding and delayed automatic shutdown control method and system for marine methanol fuel supply systems. Background Technology

[0002] With the development of low-carbon fuel applications in ships, the use of methanol fuel in inland waterway vessels, coastal vessels, and hybrid-powered vessels is gradually increasing. Methanol fuel has characteristics such as low flash point, high volatility, flammability, and toxicity. Marine methanol fuel supply systems typically require methanol day tanks, supply skids, methanol supply pumps, remote control valves, venting pumps, heating or cooling units, pressure sensors, temperature sensors, safety interlock systems, and local or remote human-machine interfaces. During ship operation, before the methanol engine transitions from a stopped state to a startable state, the fuel supply system needs to complete engine preparation, establishing suitable liquid pressure and temperature in the methanol fuel pipeline. Existing methanol fuel supply systems can typically perform functions such as liquid supply, supply shutdown, alarm, and purging, but they have the following shortcomings: Starting the methanol supply pump directly without sufficient flow in the pipeline or insufficient methanol medium at the pump inlet can easily cause the methanol supply pump to run dry, affecting the pump's reliability and lifespan. If the fuel supply system continues to run for a long time after the methanol engine is shut down, it will increase the ineffective operating time of pumps, valves and other actuators, and bring additional safety risks. When the status of multiple methanol engines changes, the system lacks the ability to perform differentiated control based on the status of each branch.

[0003] Therefore, there is an urgent need for a backup engine diversion method and system for preventing dry grinding and a delayed automatic shutdown control method for marine methanol fuel supply systems, in order to solve the problems existing in the prior art. Summary of the Invention

[0004] This invention provides a standby engine diversion anti-dry running and delayed automatic shutdown control method and system for marine methanol fuel supply systems. It addresses the problems of existing marine methanol fuel supply systems, such as the lack of pipeline pre-filling fluid protection before starting the methanol supply pump during the methanol engine standby process, which leads to the risk of dry running of the supply pump, and the possibility that the system may run idle for a long time due to lack of operation after all methanol engines are shut down and the standby engine is canceled.

[0005] The core technology of this invention is to decouple the methanol engine standby command from the start of the methanol supply pump. Before the supply pump starts, a drainage circulation driven by a diaphragm pump is established to complete the pipeline filling. After all methanol engines are shut down, the cycle holding or delayed automatic shutdown is executed according to the cancellation status of the standby command. Thus, standby, drainage, fuel supply, shutdown, cycle holding and delayed automatic shutdown are integrated into a continuous state machine control process that can be executed automatically.

[0006] In a first aspect, the present invention provides a method for preventing dry grinding and delaying automatic shutdown control of a marine methanol fuel supply system, which constructs a fuel supply state machine based on the standby state, fuel supply state, shutdown state, and standby cancellation state of the methanol engine, and includes the following steps: S1. When the marine methanol fuel supply system is in automatic operation, receive a standby command from at least one methanol engine; S2. According to the standby machine command, open the methanol daily use tank liquid supply remote control valve and the discharge diaphragm pump, open the initial diversion and return valve, so that methanol flows out of the methanol daily use tank, passes through the supply skid and returns to the methanol daily use tank through the return flow path, forming a diversion circulation to complete the pipeline filling and prevent the methanol supply pump from dry running. S3. After the priming cycle is completed, stop the diaphragm pump and close the initial priming return valve, open the shutdown cycle return valve and start the methanol supply pump. According to the liquid supply pressure feedback value and the medium temperature feedback value, perform closed-loop regulation of the methanol supply pump and the temperature regulation unit so that the liquid supply pressure and the medium temperature reach the pre-set machine conditions. S4. When the liquid supply pressure, medium temperature, safety interlock status and corresponding liquid supply branch leakage status all meet the pre-set equipment conditions, a standby completion signal is sent back to the corresponding methanol generator. S5. When a fuel supply command for the methanol engine is received, open the remote control valve for the liquid supply corresponding to the methanol engine to supply methanol fuel to the methanol engine. S6. When a methanol generator shutdown command or fuel cut-off command is received, close the liquid supply remote control valve corresponding to the methanol generator and stop supplying liquid to the methanol generator. S7. When all methanol generators are shut down but at least one standby generator command has not been cancelled, maintain the operation of the methanol supply pump to circulate methanol between the methanol day use tank and the supply skid. S8. When all methanol generators are in a shutdown state and all standby commands have been cancelled, close the methanol daily use tank supply remote control valve and stop the methanol supply pump. S9. After all standby commands have been cancelled, start the delay timer. If no manual system stop command is received within the set delay time, the marine methanol fuel supply system will automatically stop operating.

[0007] Furthermore, the procedure prior to step S1 includes: Receives automatic mode selection instructions and system start instructions; performs pre-start verification on the power supply, communication, valve status, pump status, sensor status, ventilation status and safety interlock status of the marine methanol fuel supply system; when the pre-start verification meets the preset conditions, the marine methanol fuel supply system enters automatic operation mode.

[0008] Furthermore, determining the completion of the drainage cycle includes: Collect backflow pressure, drainage duration, and feedback signals of the relevant valve opening position at the return flow path or supply skid. When the reflux pressure reaches the preset reflux pressure threshold, the drainage duration reaches the preset drainage duration threshold, and all relevant valves are in the fully open position, the drainage cycle is considered complete.

[0009] Furthermore, in step S3, the closed-loop adjustment includes: Based on the deviation between the setpoint and the feedback value of the liquid supply pressure, the speed of the methanol supply pump and / or the opening of the regulating valve are adjusted cycle by cycle. Based on the deviation between the medium temperature setpoint and the medium temperature feedback value, the temperature regulation unit is controlled to heat and / or cool the methanol medium, so that the methanol medium temperature is maintained within the preset temperature range.

[0010] Furthermore, the liquid supply pressure is set at 5.5 bar, with an allowable fluctuation range of ±0.3 bar; the preset temperature range is 5°C to 45°C; and the set delay time is two hours.

[0011] Furthermore, in step S4, before sending the standby completion signal to the corresponding methanol generator, it is also determined whether the following conditions are met simultaneously: The following conditions must be met: the methanol supply pressure reaches the set pressure range, the methanol medium temperature reaches the set temperature range, the methanol supply pump is running, the methanol day tank supply remote control valve is open, there is no first-level safety alarm in the marine methanol fuel supply system, and there is no leakage alarm in the corresponding supply branch; and a standby completion signal must be fed back when all the above conditions are met.

[0012] Furthermore, when the system has completed the diversion cycle and the methanol supply pump is in operation, the subsequent methanol generator will issue a standby command without repeating the diversion cycle in step S2. Instead, it will directly confirm the status of the corresponding liquid supply branch of the methanol generator and provide a standby completion signal when the branch status meets the preset standby conditions. If the corresponding liquid supply branch has been isolated or drained, or the branch status does not meet the preset conditions, the local filling or diversion confirmation of the liquid supply branch will be performed first.

[0013] Furthermore, it also includes abnormal interlocking steps: When at least one of the following abnormalities is detected: methanol leakage, excessive combustible gas concentration, excessive liquid supply pressure, excessive liquid supply temperature, ventilation failure, pump failure, valve switch timeout, or communication failure, at least one of the following actions will be performed according to the fault level: alarm, prohibit liquid supply, close the corresponding liquid supply remote control valve, stop the methanol supply pump, trigger emergency cut-off, or output a fault signal to the methanol generator.

[0014] Secondly, the present invention provides a backup engine dredging anti-dry grinding and delayed automatic stop control system for a marine methanol fuel supply system, comprising: Methanol daytime compartment; The methanol daily use tank supply remote control valve is located between the methanol daily use tank and the supply skid; The diaphragm pump is installed on a separate drainage branch; Methanol supply pump; Return path; The initial flow return valve is located between the supply skid outlet and the return flow path; The shutdown recirculation valve is located downstream of the methanol supply pump and between the recirculation path; Pressure detection unit, used to collect liquid supply pressure; Temperature detection unit, used to collect the temperature of methanol medium; Temperature control unit for heating and / or cooling the methanol medium; Multiple liquid supply remote control valves are installed on the liquid supply branches of each methanol generator; The fuel supply control unit is connected to the methanol day tank liquid supply remote control valve, the diaphragm pump, the methanol supply pump, the initial descent return valve, the shutdown circulation return valve, the pressure detection unit, the temperature detection unit, the temperature regulation unit, and each liquid supply remote control valve, and is configured to perform the above-described method.

[0015] Thirdly, the present invention provides a readable storage medium storing a computer program, the computer program including program code for controlling a process to execute the process, the process including the backup engine diversion anti-dry grinding and delayed automatic stop control method of the above-described marine methanol fuel supply system.

[0016] The main contributions and innovations of this invention are as follows: 1. Before starting the methanol supply pump, this invention first establishes a flow circulation between the methanol daily use tank, the supply skid, and the return flow path through a diaphragm pump and an independent drainage branch, so that the supply skid and related pipelines are in a methanol medium-filled state. From the control logic, this forms an anti-dry-run protection, preventing the methanol supply pump from starting when the medium is insufficient, which significantly improves the reliability and service life of the pump.

[0017] 2. This invention establishes stable liquid supply conditions before the methanol engine receives feedback that the standby engine has completed operation through closed-loop regulation of liquid supply pressure and medium temperature. This ensures that the methanol engine has the required liquid supply pressure and temperature at startup, thereby guaranteeing reliable startup and stable operation of the methanol engine.

[0018] 3. This invention adopts the overlay logic of the system's global diversion state and the corresponding branch's ready state. After the global diversion is completed, the subsequent methanol engine does not need to repeat the diversion cycle when issuing a standby command. At the same time, each liquid supply branch can respond independently according to the fuel supply and shutdown commands, which improves the control flexibility and response efficiency in multi-engine scenarios.

[0019] 4. This invention maintains circulation when all methanol engines are shut down but standby engine requirements are still maintained. After all standby engines are canceled, the supply pump stops and a delayed self-stop timer is activated. This takes into account both the need for rapid restoration of fuel supply and the need to reduce ineffective operation, and avoids the fuel supply system from running idle for a long time due to lack of operation, thereby improving the safety and economy of the system.

[0020] Details of one or more embodiments of the present invention are set forth in the following drawings and description, so that other features, objects and advantages of the invention will be more readily understood. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure and diversion circuit of the marine methanol fuel supply system of the present invention; Figure 2 This is a flowchart of the standby machine diversion anti-dry grinding and delayed automatic stop control method of the present invention; Figure 3 This is a schematic diagram of the fuel supply state machine transition of the present invention; Figure 4 This is a block diagram of the PLC signal connection and control module of the fuel supply control unit of the present invention.

[0022] In the diagram: 1. Methanol daily use compartment; 2. Daily use compartment liquid supply remote control valve; 3. Drainage diaphragm pump; 4. Supply skid; 5. Methanol supply pump; 6. Return flow path; 7. Pressure detection unit; 8. Temperature detection unit; 9. Liquid supply remote control valve; 10. Methanol engine; 11. Fuel supply control unit; 12. HMI display and operation unit; 13. Alarm interlock unit; 14. Communication interface; 15. Temperature regulation unit; 16. Return pressure tapping point; 17. Initial descent return valve; 18. Shutdown circulation return valve. Detailed Implementation

[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of this specification. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of this specification as detailed in the appended claims.

[0024] It should be noted that the steps of the corresponding methods are not necessarily performed in the order shown and described in this specification in other embodiments. In some other embodiments, the methods may include more or fewer steps than described in this specification. Furthermore, a single step described in this specification may be broken down into multiple steps in other embodiments; and multiple steps described in this specification may be combined into a single step in other embodiments.

[0025] Example 1 This embodiment provides a backup engine diversion anti-dry grinding and delayed automatic shutdown control method for a marine methanol fuel supply system. This method constructs a fuel supply state machine based on the backup engine state, fuel supply state, shutdown state, and backup engine cancellation state of the methanol engine. Through state machine control, it achieves automated processes for backup engine diversion, closed-loop regulation, fuel supply, shutdown cycle maintenance, and delayed automatic shutdown. The following is combined with… Figures 1 to 4 This embodiment will be described in detail.

[0026] Figure 1 This is a schematic diagram of the structure and diversion circuit of the marine methanol fuel supply system of the present invention. Figure 1 As shown, the marine methanol fuel supply system of this embodiment includes a methanol day tank 1, a day tank liquid supply remote control valve 2, a diaphragm pump for venting 3, a supply skid 4, a methanol supply pump 5, a return flow path 6, a pressure detection unit 7, a temperature detection unit 8, multiple liquid supply remote control valves 9, multiple methanol generators 10, a fuel supply control unit 11, an HMI display and operation unit 12, an alarm interlock unit 13, a communication interface 14, and a temperature regulation unit 15. Among these, Figure 1 The solid lines in the diagram represent methanol pipelines, while the dashed lines represent detection signals, control signals, or interlock signals.

[0027] The methanol supply remote control valve 2 is located between the methanol daily use tank 1 and the supply skid 4, and is used to control the flow of methanol from the methanol daily use tank 1 to the supply skid 4. The diaphragm pump 3 is located on a separate dredging branch, which connects the supply skid 4 and the methanol daily use tank 1. This branch is specifically used to establish a dredging circulation and remove residual gas from the pipeline before the methanol supply pump 5 is started. It is not connected in series with the normal fuel supply main pipeline, nor is it a continuously operating device on the return flow path 6. The supply skid 4 is used for filtering, heat exchange, and pressure regulation of methanol fuel. The methanol supply pump 5 is used to supply methanol fuel to the methanol engine 10. The return flow path 6 is used to return methanol from the supply skid 4 side to the methanol daily use tank 1.

[0028] This embodiment features two independently functioning reflux valves. The initial priming reflux valve 17 is located between the outlet of the supply skid 4 and the reflux path 6, used to establish a priming circulation before the methanol supply pump 5 starts. The shutdown circulation reflux valve 18 is located between the supply line downstream of the methanol supply pump 5 and upstream of the supply remote control valve 9 and the reflux path 6, used for standby circulation and shutdown circulation maintenance after the methanol supply pump 5 starts. The fuel supply control unit 11 controls the opening and closing of the two reflux valves respectively and receives corresponding valve position feedback.

[0029] Each remote-controlled methanol supply valve 9 is installed on the methanol supply branch of each methanol generator 10, and is used to independently control the on / off of the methanol supply to each methanol generator 10. The pressure detection unit 7 is used to collect the methanol supply pressure in the supply pipeline, and can be implemented using a pressure transmitter. The temperature detection unit 8 is used to collect the methanol medium temperature in the supply pipeline, and can be implemented using a temperature transmitter. The temperature control unit 15 includes a water-glycol circulating pump, a heater, and / or a heat exchanger, used to heat and / or cool the methanol medium. The fuel supply control unit 11 is connected to the above-mentioned pump, valve, detection unit, temperature control unit 15, HMI display operation unit 12, alarm interlock unit 13, and communication interface 14. The fuel supply control unit 11 can be implemented using a programmable logic controller (PLC), industrial computer, or embedded controller.

[0030] Figure 2 This is a flowchart of the standby machine diversion anti-dry grinding and delayed automatic stop control method of the present invention. Figure 3 This is a schematic diagram of the fuel supply state machine transition of the present invention. Figure 4 This is a block diagram of the PLC signal connection and control module of the fuel supply control unit of the present invention. The following is in conjunction with... Figure 2 , Figure 3 and Figure 4 The control method steps of this embodiment will be described in detail.

[0031] Step S1: The system enters automatic operation mode and receives standby instructions. First, the operator selects the automatic mode and issues a system start command via the HMI display unit 12. The fuel supply control unit 11 performs a pre-start check on the power supply, communication, valve status, pump status, sensor status, ventilation status, and safety interlock status of the marine methanol fuel supply system. After the check passes, the system enters automatic operation mode.

[0032] In automatic operation, the fuel supply control unit 11 monitors the status signals of each methanol generator 10 in real time via the communication interface 14 or passive contacts. When a standby command is received from at least one methanol generator 10, the system enters the standby command receiving state. Figure 3(In the S1 state), and then execute subsequent steps. Standby engine commands, fuel supply commands, shutdown commands, fuel cut-off commands, standby engine completion signals, and system operation signals can be transmitted via passive contact signals, RS485, Ethernet, CAN, Modbus, or other marine communication methods.

[0033] Step S2: Establish a drainage cycle According to the standby command, the fuel supply control unit 11 opens the day tank liquid supply remote control valve 2 and the diaphragm pump 3, and opens the initial diversion return valve 17, while keeping the shutdown circulation return valve 18 and the liquid supply remote control valve 9 closed. Methanol is drawn from the methanol day tank 1, enters the supply skid 4 through the day tank liquid supply remote control valve 2, then enters the return path 6 through the initial diversion return valve 17 at the outlet of the supply skid 4, and finally returns to the methanol day tank 1, forming a diversion circulation driven by the diaphragm pump 3.

[0034] This drainage circulation ensures that the supply skid 4 and related pipelines are filled with methanol medium, and discharges residual gas from the pipelines, thereby preventing the methanol supply pump 5 from starting when the medium is insufficient and causing dry grinding.

[0035] The completion of the drainage cycle is indicated by the drainage completion sign. Characterization. For example... Figure 1 As shown, a return pressure tapping point 16 is provided on the return outlet side of the supply skid 4 or on the side of the return path 6 near the supply skid 4 to collect the return pressure. The fuel supply control unit 11 calculates the diversion completion flag according to the following criteria. :

[0036] In the formula, This marks the completion of the lead generation process. To provide return pressure at the return path 6 or at the supply skid 4, Set the backflow pressure value. For the duration of traffic diversion, Minimum drainage time, This is the integrated logic value for the feedback of the opening position of the daytime use compartment liquid supply remote control valve 2, the initial drainage return valve 17, and related valves. This integrated logic value is obtained by ANDing the opening position feedback signals of each valve, that is, when all related valves are fully open. It is 1. When When the value is 1, the drainage cycle is considered complete; when... If the value is not 1, methanol supply pump 5 is not allowed to be started.

[0037] and The settings should be determined based on the supply skid 4 volume, return pipeline length, diaphragm pump 3 flow rate, and shipboard commissioning results. These values ​​are taken as typical engineering examples. A pressure of 0.05 MPa to 0.20 MPa (approximately 0.5 bar to 2.0 bar) can be used to confirm that the reflux has been established. The time can be from 30 seconds to 180 seconds, and can be extended to 3 to 5 minutes for initial commissioning or when the pipeline volume is large. The above values ​​are example ranges and do not constitute unique limitations.

[0038] Step S3: Stop the siphon pump and start the methanol supply pump for closed-loop regulation. After determining that the drainage cycle is complete (i.e.) Afterwards, the fuel supply control unit 11 first stops the diaphragm pump 3 and closes the initial drainage return valve 17, then opens the shutdown circulation return valve 18, and finally starts the methanol supply pump 5. Through the above pump and valve switching, the drainage circulation is switched to the standby circulation driven by the methanol supply pump 5. At this time, methanol enters the supply skid 4 from the methanol day use tank 1 through the day use tank liquid supply remote control valve 2, is pressurized by the methanol supply pump 5, passes through the pressure detection unit 7 and the temperature detection unit 8, and then enters the return circulation path 6 through the shutdown circulation return valve 18, returning to the methanol day use tank 1.

[0039] During the operation of methanol supply pump 5, pressure detection unit 7 operates according to the control cycle. The fuel supply control unit 11 collects the real-time feedback value of the liquid supply pressure and the real-time feedback value of the methanol medium temperature. Based on the deviation between the liquid supply pressure setpoint and the pressure feedback value, the fuel supply control unit 11 performs closed-loop regulation of the speed of the methanol supply pump 5 and / or the opening of the regulating valve; based on the deviation between the medium temperature setpoint and the temperature feedback value, it controls the temperature regulation unit 15 to perform bidirectional temperature regulation so that the liquid supply pressure and the medium temperature reach the pre-set operating conditions.

[0040] In pressure closed-loop control, the fuel supply control unit 11 operates according to the control cycle. Collect liquid supply pressure feedback value And calculate the pressure deviation. :

[0041] Furthermore, the speed command for methanol supply pump 5 is updated according to an incremental PID control law:

[0042] In the formula, Set the liquid supply pressure value. For the first The liquid supply pressure feedback value for each control cycle. For pressure deviation, The speed command for methanol supply pump 5 is given. , and These are the proportional coefficient, integral coefficient, and differential coefficient, respectively. To control the cycle.

[0043] In closed-loop control of medium temperature, temperature deviation and temperature adjustment commands They can be represented as:

[0044]

[0045] In the formula, The target temperature for the methanol medium is... For the first The methanol medium temperature feedback value for each control cycle For temperature deviation, The function is the adjustment command for the temperature control unit 15. It can be a piecewise function, a proportional adjustment function, or a lookup table function.

[0046] The temperature control unit 15 employs a two-way temperature control logic: when the methanol temperature is below the set range, it is heated via a water-glycol circulating pump, heater, or heat exchanger; when the temperature is above the set range, it is cooled or the temperature rise is suppressed via cooling water or a water-glycol cooling circuit, heat exchanger, or by reducing the heating input. Actual vessels can be configured with either a heating-only scheme or an integrated heating and cooling scheme, depending on the navigation area, ambient temperature, and methanol engine requirements.

[0047] In a preferred embodiment, the liquid supply pressure setting value is... The allowable pressure is 5.5 bar, with a fluctuation range of ±0.3 bar, i.e., the allowable pressure deviation. The pressure is 0.3 bar; the preset temperature range for the methanol medium is 5°C to 45°C, which is the lower limit of the allowable temperature. 5℃, the upper limit of permissible temperature The temperature is 45°C. In other embodiments, the supply pressure and temperature range can also be adjusted according to the model of the methanol generator 10, flow requirements, the ship's navigation area, and classification society requirements.

[0048] Step S4: Feedback of standby completion signal When the liquid supply pressure, medium temperature, safety interlock status, and corresponding liquid supply branch leakage status all meet the pre-equipment conditions, the fuel supply control unit 11 sends a standby completion signal to the corresponding methanol engine 10 through the communication interface 14 or passive contact.

[0049] To avoid using pump operation or valve opening as the sole criterion for standby completion, this embodiment includes a standby completion indicator. Before sending the standby completion signal to the corresponding methanol generator 10, the following conditions must be checked simultaneously: Traffic diversion completion sign =1; Liquid supply pressure deviation Within the allowable pressure deviation Within the range, The preferred value in this embodiment is 0.3 bar. methanol medium temperature At the lower limit of the allowable temperature With the upper limit of allowable temperature Between, among and These refer to 5℃ and 45℃ in the preferred embodiment, respectively. The system does not have a Level 1 security alarm (i.e.) ); There is no leakage alarm in the corresponding liquid supply branch (i.e.) ).

[0050] Standby completion indicator satisfy:

[0051] In the formula, To allow for pressure deviation, and These are the lower limit of the allowable temperature and the upper limit of the allowable temperature, respectively. This is a Level 1 safety alarm indicator (1 indicates an alarm is present, 0 indicates normal). This corresponds to the leak alarm indicator for the liquid supply branch (1 indicates a leak, 0 indicates normal). It applies only if... When the value is 1, the fuel supply control unit 11 sends a standby signal to the corresponding methanol engine 10.

[0052] Step S5: Fuel Supply Control When the fuel supply control unit 11 receives a fuel supply command from a methanol engine 10, it opens the corresponding liquid supply remote control valve 9 of that methanol engine 10, allowing methanol fuel to be supplied to that methanol engine 10 via the liquid supply pipeline. When multiple methanol engines 10 issue fuel supply commands simultaneously or sequentially, the fuel supply control unit 11 opens the corresponding liquid supply remote control valve 9 of each methanol engine 10, and adjusts the speed of the methanol supply pump 5 and / or the valve opening according to the total flow demand of the multiple methanol engines 10 to keep the liquid supply pressure stable.

[0053] Step S6: Shutdown or oil cut-off control When the fuel supply control unit 11 receives a shutdown command or fuel cut-off command from a methanol engine 10, it closes the remote control valve 9 corresponding to that methanol engine 10, stopping the fuel supply to that methanol engine 10. After closing, the fuel supply control unit 11 continues to monitor the valve position feedback, pressure feedback, and leakage detection signals of that fuel supply branch. If the valve position feedback, pressure, or leakage detection is abnormal, the alarm interlock unit 13 issues a corresponding alarm signal.

[0054] Step S7: Stop Cycle Hold When all methanol generators 10 are shut down, but at least one standby command remains uncancelled, the fuel supply control unit 11 closes the initial diversion return valve 17 and the corresponding liquid supply remote control valve 9 for each shut-down methanol generator 10, keeps the shutdown circulation return valve 18 open, and maintains the operation of the methanol supply pump 5. At this time, methanol flows from the methanol day use tank 1 through the day use tank liquid supply remote control valve 2 into the supply skid 4, is pressurized by the methanol supply pump 5, and then enters the return path 6 through the shutdown circulation return valve 18, returning to the methanol day use tank 1. The system maintains standby liquid supply conditions so that liquid supply can be quickly restored when the methanol generator 10 issues a new fuel supply command.

[0055] Step S8: Cancel standby unit and stop supply pump When all methanol generators 10 are in a shutdown state and all standby commands have been cancelled, the fuel supply control unit 11 closes the methanol day tank liquid supply remote control valve 2 and stops the methanol supply pump 5.

[0056] Step S9: Delayed Automatic Stop After all standby commands have been cancelled, the fuel supply control unit 11 initiates a delay timer. If the set delay time is reached... Inside, the operator clicks the system stop button on the HMI display unit 12, and the system stops running according to the manual stop command, and the delay timer immediately terminates; if the set delay time is... If no manual system stop command is received, the fuel supply control unit 11 will automatically stop the operation of the marine methanol fuel supply system.

[0057] In the delayed automatic shutdown control, the fuel supply control unit 11 calculates the automatic shutdown flag based on the number of methanol generators in operation, the number of backup generators required, and the cumulative time after the backup generators are cancelled. :

[0058] In the formula, This is the automatic shutdown indicator. This refers to the number of methanol generators that are in operation or supplying fuel. In order to maintain the number of methanol generators required for standby operation (i.e., standby orders have not been cancelled), This is the cumulative timeout after all backup units are cancelled. To set the delay time. When When the value is 1, the fuel supply control unit 11 automatically stops the operation of the fuel supply system.

[0059] In this embodiment, a delay time is set. The delay is two hours. This delay allows operators a window for manual intervention while also preventing the fuel supply system from idling for an extended period after all methanol generators have been deactivated from standby.

[0060] After automatic shutdown, the system defaults to a stop or standby state. When resuming liquid supply, the operator must first issue a restart permission on the HMI display unit 12, or the upper control system must reissue a system start or permission signal and re-perform the pre-start verification. After successful verification, the methanol generator 10 issues a standby command again, and the system enters step S1 and subsequent processes. If the ship project is equipped with an automatic wake-up function, it must be based on the premise that the automatic mode remains effective, there are no safety interlocks, and the HMI or upper control system has automatic recovery permission; the start confirmation cannot be bypassed solely by a standby command.

[0061] In this embodiment, the multi-machine standby timing overlay logic is as follows: This embodiment employs a system-wide global diversion state and corresponding branch readiness state overlay logic for scenarios where multiple methanol generators 10 alternately issue standby commands. When the system has completed global diversion, the methanol supply pump 5 is running, and the main pipeline's liquid supply pressure, medium temperature, and safety interlock status meet the pre-setup conditions, subsequent standby commands from methanol generators 10 do not require repeating the global diversion cycle of step S2. The fuel supply control unit 11 directly confirms the valve position feedback and leakage status of the corresponding liquid supply branch of the methanol generator 10 and displays the standby completion flag. When the conditions are met, a standby completion signal is sent back to the methanol generator 10. If the target liquid supply branch has been isolated or drained, or if the valve position, pressure, or leakage status does not meet the conditions, then the partial filling or drainage confirmation of that branch is performed first.

[0062] In this embodiment, the abnormal interlock control is as follows: This embodiment also includes an abnormal interlocking step. When the fuel supply control unit 11 detects at least one of the following abnormalities through the alarm interlocking unit 13: methanol leakage, excessive combustible gas concentration, excessive liquid supply pressure, excessive liquid supply temperature, ventilation failure, pump failure, valve switch timeout, or communication failure, it executes corresponding protection actions according to the fault level. Specifically, for low-level faults, an audible and visual alarm can be triggered, and manual intervention can be prompted on the HMI display operation unit 12; for high-level faults, at least one of the following actions can be executed: prohibiting liquid supply, closing the corresponding liquid supply remote control valve 9, stopping the methanol supply pump 5, triggering an emergency cut-off, or outputting a fault signal to the methanol generator 10.

[0063] In this embodiment, the state machine transition logic is as follows: like Figure 3 As shown, the fuel supply control unit 11 responds to the standby command and the diversion completion flag. Standby completion indicator Fuel supply command, shutdown command, standby unit cancellation status, delayed automatic shutdown flag The system switches between the following states: standby state S0, standby command receiving state S1, flow circulation state S2, liquid supply closed-loop regulation state S3, standby completion state S4, oil supply state S5, shutdown cycle holding state S6, standby delay cancellation state S7, automatic shutdown state S8, and fault interlock state SF.

[0064] The specific switching logic is as follows: When the system is in standby state S0 and receives the standby command from methanol generator 10, it enters standby command receiving state S1; when the main pipeline is not filled with liquid, the system enters the drainage circulation state S2 from S1; when When the value is 1, the system enters the liquid supply closed-loop regulation state S3; when When the value is 1, the system enters the standby engine completion state S4 and sends a standby engine completion signal back to methanol generator 10; when a fuel supply command is received, the system enters the fuel supply state S5; when a shutdown or fuel cut-off command is received, if there is still a standby engine demand, the system enters the shutdown cycle hold state S6; when all standby engines are cancelled, the system enters the standby engine delay cancellation state S7; when... When the value is 1, the system enters the automatic shutdown state S8; when any critical fault signal is triggered, the system enters the fault interlock state SF. After the fault is cleared and reset, the system returns to the standby state S0.

[0065] In this embodiment, the control unit module structure is as follows: like Figure 4 As shown, the fuel supply control unit 11 includes the following functional modules: automatic mode and pre-start verification module, standby engine priming anti-dry-running module, priming completion criterion module, pressure and temperature closed-loop regulation module, standby engine completion criterion module, fuel supply and shutdown branch control module, shutdown cycle holding module, time-delayed automatic stop module, and alarm interlock module. These modules can be implemented by a PLC, industrial computer, embedded controller, or a combination thereof, and the functions of each module are executed by the computer program running in the fuel supply control unit 11.

[0066] The input signals of the fuel supply control unit 11 include: standby, fuel supply, and shutdown signals for the methanol engine 10; pressure detection signals; temperature detection signals; valve position feedback signals for the daytime use tank liquid supply remote control valve 2, initial descent return valve 17, shutdown circulation return valve 18, and liquid supply remote control valve 9; pump operation feedback signals; HMI commands; and alarm interlock input signals. The output signals of the fuel supply control unit 11 include: control signals for the daytime use tank liquid supply remote control valve 2, initial descent return valve 17, shutdown circulation return valve 18, diaphragm pump 3, methanol supply pump 5, liquid supply remote control valve 9, alarm interlock output signals, and HMI or communication output signals.

[0067] Example 2 This embodiment provides an extreme operating condition application example of the method in Embodiment 1. A preferred embodiment of the invention uses a supply pressure setting of 5.5 bar, a temperature range of 5°C to 45°C, and a delay time of two hours; however, these values ​​are not the only limitations. In certain ship types or under extremely cold or high-temperature navigation conditions, the supply pressure setting may vary. The setpoint can be configured with a low limit of 4.0 bar or a high limit of 8.0 bar, with an allowable fluctuation range of ±0.5 bar; the preset medium temperature range can be set from a low limit of 0°C to a high limit of 60°C; and the delay time can be set. The setting can be set to 0.5 hours or 4 hours based on the short-term port call requirements of ships. Backflow pressure setting threshold. The pressure can be set to 0.05MPa or 0.20MPa, with a minimum drainage duration. The time limit can be set to 30s or 180s. Under such extreme parameter configurations, the state machine control architecture, anti-dry-running flow logic, and closed-loop adjustment algorithm of this invention maintain completely consistent operating logic and control stability, and the execution flow of each step S1 to S9 is the same as in Embodiment 1.

[0068] Example 3 This embodiment provides a marine methanol fuel supply control system, the hardware components and pipeline and signal connection relationships of which are as follows: Figure 1 And Embodiment 1. The fuel supply control unit 11 stores a computer program, and when the processor executes the program, it implements the control method steps of Embodiment 1 or Embodiment 2. The system also includes an HMI display operation unit 12, which is connected to the fuel supply control unit 11 and is used to receive operation commands and display the system operating status.

[0069] Example 4 This embodiment also provides a readable storage medium storing a computer program, which includes program code for controlling and executing a process, the process including the backup engine diversion anti-dry grinding and delayed automatic stop control method for a marine methanol fuel supply system according to Embodiment 1.

[0070] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0071] Generally, various embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention can be implemented in hardware, while others can be implemented by firmware or software executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the invention may be shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, by way of non-limiting example, these blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0072] Embodiments of the present invention can be implemented by computer software, which may be executable by a data processor of a mobile device, such as a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products) including software routines, applets, and / or macros can be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. The computer program product may include one or more computer-executable components configured to perform the embodiments when the program is run. The one or more computer-executable components may be at least one piece of software code or a portion thereof. Additionally, it should be noted in this respect that, as Figure 1 Any box in the logical flow can represent a program step, or interconnected logic circuits, boxes and functions, or a combination of program steps and logic circuits, boxes and functions. Software can be stored on physical media such as memory chips or blocks of storage implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, CDs, etc. The physical medium is a non-transient medium.

[0073] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system, characterized in that, Construct a fuel supply state machine based on the methanol engine's standby state, fuel supply state, shutdown state, and standby cancellation state, including the following steps: S1. When the marine methanol fuel supply system is in automatic operation, receive a standby command from at least one methanol engine; S2. According to the standby machine command, open the methanol daily use tank liquid supply remote control valve and the discharge diaphragm pump, open the initial diversion and return valve, so that methanol flows out of the methanol daily use tank, passes through the supply skid and returns to the methanol daily use tank through the return flow path, forming a diversion circulation to complete the pipeline filling and prevent the methanol supply pump from dry running. S3. After determining that the drainage cycle is completed, stop the diaphragm pump and close the initial drainage return valve, open the shutdown cycle return valve and start the methanol supply pump, and perform closed-loop regulation of the methanol supply pump and temperature regulation unit according to the liquid supply pressure feedback value and the medium temperature feedback value, so that the liquid supply pressure and the medium temperature reach the pre-set machine conditions. S4. When the liquid supply pressure, medium temperature, safety interlock status and corresponding liquid supply branch leakage status all meet the pre-set equipment conditions, a standby completion signal is sent back to the corresponding methanol generator. S5. When a fuel supply command for the methanol engine is received, open the remote control valve for the liquid supply corresponding to the methanol engine to supply methanol fuel to the methanol engine. S6. When a methanol generator shutdown command or fuel cut-off command is received, close the liquid supply remote control valve corresponding to the methanol generator and stop supplying liquid to the methanol generator. S7. When all methanol generators are in a shutdown state but at least one standby generator command has not been cancelled, maintain the operation of the methanol supply pump to circulate methanol between the methanol day use tank and the supply skid. S8. When all methanol generators are in a shutdown state and all standby commands have been cancelled, close the methanol daily use tank supply remote control valve and stop the methanol supply pump. S9. After all standby commands have been cancelled, start a delay timer. If no manual system stop command is received within the set delay time, the marine methanol fuel supply system will automatically stop operating.

2. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 1, characterized in that, Step S1 is preceded by: Receive automatic mode selection command and system start command; perform pre-start verification on the power supply, communication, valve status, pump status, sensor status, ventilation status and safety interlock status of the marine methanol fuel supply system; when the pre-start verification meets the preset conditions, enable the marine methanol fuel supply system to enter automatic operation state.

3. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 1, characterized in that, Determining the completion of the drainage cycle includes: Collect the return pressure, drainage duration, and related valve opening feedback signals at the return flow path or the supply skid. When the reflux pressure reaches a preset reflux pressure threshold, the drainage duration reaches a preset drainage duration threshold, and all relevant valves are in the fully open state, the drainage cycle is determined to be complete.

4. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 1, characterized in that, In step S3, closed-loop regulation includes: Based on the deviation between the setpoint and the feedback value of the liquid supply pressure, the speed of the methanol supply pump and / or the opening of the regulating valve are adjusted cycle by cycle. Based on the deviation between the medium temperature setpoint and the medium temperature feedback value, the temperature regulation unit is controlled to heat and / or cool the methanol medium, so that the methanol medium temperature is maintained within the preset temperature range.

5. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 4, characterized in that, The liquid supply pressure is set to 5.5 bar, with an allowable fluctuation range of ±0.3 bar; the preset temperature range is 5°C to 45°C; and the preset delay time is two hours.

6. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 1, characterized in that, In step S4, before sending the standby completion signal to the corresponding methanol generator, it is also determined whether the following conditions are met simultaneously: The following conditions must be met: the methanol supply pressure reaches the set pressure range, the methanol medium temperature reaches the set temperature range, the methanol supply pump is in operation, the methanol day tank supply remote control valve is open, the marine methanol fuel supply system has no first-level safety alarm, and the corresponding supply branch has no leakage alarm; and a standby completion signal must be fed back when all the above conditions are met.

7. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 1, characterized in that, When the system has completed the diversion cycle and the methanol supply pump is running, the subsequent methanol generator will issue a standby command without repeating the diversion cycle in step S2. Instead, the branch status of the corresponding liquid supply branch of the methanol generator will be confirmed directly, and a standby completion signal will be fed back when the branch status meets the preset standby conditions. If the corresponding liquid supply branch has been isolated or drained, or the branch status does not meet the preset conditions, the partial filling or diversion confirmation of the liquid supply branch will be performed first.

8. The method for preventing dry grinding and delaying automatic shutdown of a marine methanol fuel supply system as described in claim 1, characterized in that, It also includes abnormal interlocking steps: When at least one of the following abnormalities is detected: methanol leakage, excessive combustible gas concentration, excessive liquid supply pressure, excessive liquid supply temperature, ventilation failure, pump failure, valve switch timeout, or communication failure, at least one of the following actions will be performed according to the fault level: alarm, prohibit liquid supply, close the corresponding liquid supply remote control valve, stop the methanol supply pump, trigger emergency cut-off, or output a fault signal to the methanol generator.

9. A marine methanol fuel supply control system, characterized in that, include: Methanol daytime compartment; A methanol daily use tank supply remote control valve is installed between the methanol daily use tank and the supply skid; The diaphragm pump is installed on a separate drainage branch; Methanol supply pump; Return path; An initial flow return valve is installed between the supply skid outlet and the return flow path; A shutdown recirculation valve is installed downstream of the methanol supply pump and between the recirculation path; Pressure detection unit, used to collect liquid supply pressure; Temperature detection unit, used to collect the temperature of methanol medium; Temperature control unit for heating and / or cooling the methanol medium; Multiple liquid supply remote control valves are installed on the liquid supply branches of each methanol generator; The fuel supply control unit is connected to the methanol day tank liquid supply remote control valve, the venting diaphragm pump, the methanol supply pump, the initial drainage return valve, the shutdown circulation return valve, the pressure detection unit, the temperature detection unit, the temperature regulation unit, and each of the liquid supply remote control valves, and is configured to perform the method described in any one of claims 1 to 8.

10. A marine methanol fuel supply control system as described in claim 9, characterized in that, It also includes an HMI display operation unit, which is connected to the fuel supply control unit and is used to receive operation commands and display the system operating status.

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