Automatic control system for ammonia fuel supply

Abstract

This invention provides an automatic control system for ammonia fuel supply, belonging to the field of intelligent equipment operation monitoring technology. The system includes: an unloading arm, an unloading compressor, a liquid ammonia storage tank, a low-pressure pump, a high-pressure pump, a first heat exchanger, a dual filter, and a controller. The unloading arm is connected to the filling port of the liquid ammonia storage tank, and the unloading compressor is connected to the gas outlet of the liquid ammonia storage tank. The low-pressure pump, the high-pressure pump, the first heat exchanger, and the dual filter are sequentially connected to the liquid ammonia outlet of the liquid ammonia storage tank via pipelines, and an outlet valve is provided at the liquid ammonia outlet of the liquid ammonia storage tank. The controller is used to control the operating modes of the low-pressure pump, the high-pressure pump, the first heat exchanger, and the dual filter to adjust the pressure, temperature, and purity of the output ammonia fuel to the target range. This invention can achieve the purpose of providing ammonia fuel with the required pressure, temperature, and purity to the target equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent device operation monitoring, and particularly relates to an automatic control system for ammonia fuel supply. BACKGROUND

[0002] Ammonia fuel has broad application prospects in the shipping industry, especially in the context of achieving zero carbon emission targets. Ammonia fuel has the potential to become an important fuel choice for the shipping industry. With technological advancements and changes in international shipping regulations, the use of ammonia fuel will become more widespread. Continued research at home and abroad will contribute to the green transformation of the global shipping industry. Ammonia is one of the most promising new energy fuels in the current decarbonization roadmap for the shipping industry. Under the premise of safety, how to efficiently and conveniently store and use ammonia fuel on ships is a major challenge facing the shipping industry.

[0003] With the application and promotion of dual-fuel engines and new energy fuels, pollution emissions are reduced while ship operating costs are significantly reduced. Due to the special physical and chemical properties of ammonia, existing fuel supply systems such as diesel, LNG, and methanol are not suitable, so it is necessary to design and develop an ammonia fuel supply system to provide ammonia fuel with pressure, temperature, and purity that meet the requirements of the target device. SUMMARY

[0004] Therefore, it is necessary to provide an automatic control system for ammonia fuel supply to achieve the purpose of providing ammonia fuel with pressure, temperature, and purity that meet the requirements of the target device.

[0005] To solve the above problems, the present application provides an automatic control system for ammonia fuel supply, comprising: an unloading crane pipe, an unloading compressor, a liquid ammonia storage tank, a low-pressure pump, a high-pressure pump, a first heat exchanger, a double filter, and a controller.

[0006] The unloading crane pipe is in communication with the filling port of the liquid ammonia storage tank, and the unloading compressor is in communication with the gas outlet of the liquid ammonia storage tank.

[0007] The low-pressure pump, the high-pressure pump, the first heat exchanger, and the double filter are sequentially connected by pipelines at the liquid ammonia outlet of the liquid ammonia storage tank, and an outlet valve is arranged at the liquid ammonia outlet of the liquid ammonia storage tank.

[0008] The controller is used to control the working mode of the low-pressure pump, the high-pressure pump, the first heat exchanger, and the double filter, so as to adjust the pressure, temperature, and purity of the output ammonia fuel to the target range.

[0009] In one possible implementation, the automatic control system for ammonia fuel supply further comprises: a glycol expansion tank, a glycol pump, a heater, a cooler, and a water chiller.

[0010] The heater and the cooler are both communicated with the first heat exchanger through the glycol pump, and the glycol expansion tank is communicated with the first heat exchanger;

[0011] The water chiller is communicated with the cooler.

[0012] In a possible implementation, the glycol pump comprises a first glycol pump and a second glycol pump;

[0013] The input ends of the first glycol pump and the second glycol pump are communicated with each other, and the output ends are communicated with each other, forming a first loop;

[0014] The heater and the cooler are both communicated with the first heat exchanger through the first loop.

[0015] In a possible implementation, the automatic control system of ammonia fuel supply further comprises a first pressure sensor arranged between the first loop and the heater and the cooler;

[0016] The controller is further configured to receive the glycol outlet pressure collected by the first pressure sensor, and control the high-pressure pump, the low-pressure pump, the first glycol pump and the second glycol pump to stop working when the glycol outlet pressure is greater than a first target pressure threshold.

[0017] In a possible implementation, a filling valve is arranged on the pipeline between the unloading crane and the liquid ammonia storage tank, and a gas-phase pipeline valve is arranged on the pipeline between the unloading compressor and the gas outlet of the liquid ammonia storage tank;

[0018] The controller is further configured to control the filling valve and the gas-phase pipeline valve to be opened in the unloading mode.

[0019] In a possible implementation, the low-pressure pump comprises a first low-pressure pump and a second low-pressure pump, and the high-pressure pump comprises a first high-pressure pump and a second high-pressure pump; the input ends of the first low-pressure pump and the second low-pressure pump are communicated with each other, and the output ends are communicated with each other, forming a second loop; the input ends of the first high-pressure pump and the second high-pressure pump are communicated with each other, and the output ends are communicated with each other, forming a third loop;

[0020] The second loop, the third loop, the first heat exchanger and the double filter are sequentially communicated and then communicated with the liquid ammonia outlet of the liquid ammonia storage tank;

[0021] Further, the output end of the second loop is further communicated with the input end of the first heat exchanger through a bypass backflow valve;

[0022] The controller is also used to control the opening of the filling valve, the outlet valve and the bypass reflux valve after controlling the low-pressure pump to start, and to adjust the liquid ammonia flow rate by controlling the bypass reflux valve.

[0023] In one possible implementation, the automatic control system for ammonia fuel supply includes a dual filter comprising: a first dual filter and a second dual filter.

[0024] The input ends of the first dual filter and the second dual filter are both connected to the output end of the first heat exchanger, and the output ends of the first dual filter and the second dual filter are provided with a second pressure sensor.

[0025] The controller is also configured to receive the liquid ammonia pressure difference between the output of the first dual filter and the second dual filter collected by the second pressure sensor, and issue a reminder to replace the dual filter element when the liquid ammonia pressure difference is greater than the second target pressure threshold.

[0026] In one possible implementation, the automatic control system for ammonia fuel supply further includes: an injector cooling water module consisting of a cooling water tank, a second heat exchanger, and a cooling water pump connected in sequence, the injector cooling water module being used to supply cooling water to the ammonia injector.

[0027] In one possible implementation, the automatic control system for ammonia fuel supply also includes: an ammonia collection tank and a first scrubbing cabinet;

[0028] The input end of the ammonia collection tank is connected to the liquid ammonia storage tank via a vent valve, and the output end of the ammonia collection tank is connected to the first washing cabinet.

[0029] In one possible implementation, the automatic control system for ammonia fuel supply also includes: a gas-liquid separator and a second scrubbing tank.

[0030] The input end of the gas-liquid separator is connected to the output end of the low-pressure pump, and the output end of the gas-liquid separator is connected to the second washing cabinet.

[0031] The beneficial effects of the above implementation method are as follows: The automatic control system for ammonia fuel supply provided by the present invention adds liquid ammonia fuel to the filling port of the liquid ammonia storage tank through the unloading arm. During the addition of liquid ammonia fuel, the operation of the unloading compressor ensures that the pressure inside the liquid ammonia storage tank is within a suitable range, thereby ensuring that the unloading arm smoothly adds liquid ammonia fuel to the liquid ammonia storage tank. When the liquid ammonia storage tank outputs ammonia fuel, the working modes of the low-pressure pump and the high-pressure pump are controlled to adjust the pressure of the output ammonia fuel, so that the pressure of the output ammonia fuel meets the requirements. The first heat exchanger is used to exchange heat with the output ammonia fuel, so that the temperature of the output ammonia fuel meets the requirements. The dual filter is used to filter the ammonia fuel, so that the purity of the output ammonia fuel meets the requirements. Therefore, the automatic control system for ammonia fuel supply provided by the present invention can achieve the purpose of providing the target equipment with ammonia fuel that meets the requirements in terms of pressure, temperature and purity. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic block diagram of an embodiment of the automatic control system for ammonia fuel supply provided by the present invention;

[0034] Figure 2 A partial structural schematic diagram of another embodiment of the automatic control system for ammonia fuel supply provided by the present invention;

[0035] Figure 3 This is a partial structural schematic diagram of yet another embodiment of the automatic control system for ammonia fuel supply provided by the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0038] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0039] The naming or numbering of steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effect can be achieved.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0041] like Figure 1 As shown, the present invention provides an automatic control system for ammonia fuel supply, including: unloading arm 101, unloading compressor 102, liquid ammonia storage tank 103, low-pressure pump 104, high-pressure pump 105, first heat exchanger 106, dual filter 107 and controller (not shown in the figure).

[0042] The unloading arm 101 is connected to the filling port of the liquid ammonia storage tank 103, and the unloading compressor 102 is connected to the gas outlet of the liquid ammonia storage tank 103.

[0043] The low-pressure pump 104, the high-pressure pump 105, the first heat exchanger 106 and the dual filter 107 are sequentially connected to the liquid ammonia outlet of the liquid ammonia storage tank 103 through pipelines, and an outlet valve is provided at the liquid ammonia outlet of the liquid ammonia storage tank 103.

[0044] The controller is used to control the operating modes of the low-pressure pump 104, the high-pressure pump 105, the first heat exchanger 106, and the dual filter 107 to adjust the pressure, temperature, and purity of the output ammonia fuel to the target range.

[0045] It is understood that the controller provided by this invention can be a PLC (Programmable Logic Controller).

[0046] The unloading arm 101 is connected to the filling port of the liquid ammonia storage tank 103, and liquid ammonia fuel can be added to the liquid ammonia storage tank 103 through the unloading arm 101. The unloading compressor 102 is connected to the gas outlet of the liquid ammonia storage tank 103. When adding liquid ammonia fuel, the unloading compressor 102 can be controlled to start working to ensure the internal gas pressure of the liquid ammonia storage tank 103 when adding liquid ammonia fuel, thereby successfully realizing the addition of liquid ammonia fuel.

[0047] The controller ensures that the pressure of the liquid ammonia delivered from the liquid ammonia storage tank 103 meets the requirements by controlling the operation of the low-pressure pump 104 and the high-pressure pump 105. It also ensures that the temperature of the ammonia fuel output from the liquid ammonia storage tank 103 meets the requirements by controlling the operation of the first heat exchanger 106. Finally, it ensures that the purity of the ammonia fuel meets the requirements by controlling the operation of the dual filter 107. Thus, the controller ensures that the pressure, temperature and purity of the supplied ammonia fuel meet the requirements.

[0048] This invention analyzes the characteristics of ammonia fuel and designs a complete ammonia fuel supply system for novel ammonia fuel engines. Furthermore, it develops an automatic control and monitoring system for ammonia fuel supply based on a PLC and a host computer. This system includes ammonia fuel filling, storage, transportation, and supply systems. Each subsystem has its corresponding high-frequency sensors for temperature, pressure, and flow, as well as control valves such as solenoid valves, bypass valves, and safety valves. This achieves automatic control and comprehensive monitoring of each process and subsystem, improving the system's convenience and efficiency while strictly ensuring system safety.

[0049] In some embodiments, such as Figure 2 As shown, the automatic control system for ammonia fuel supply also includes: an ethylene glycol expansion tank, an ethylene glycol pump, a heater, a cooler, and a chiller unit.

[0050] The heater and the cooler are both connected to the first heat exchanger 106 via the ethylene glycol pump, and the ethylene glycol expansion tank is also connected to the first heat exchanger 106.

[0051] The chiller unit is connected to the cooler.

[0052] Understandably, the ethylene glycol heat exchange system comprises an expansion tank, ethylene glycol pump, heater, cooler, and chiller unit. This system operates in both heating and cooling modes, and the control system automatically switches modes based on a comparison between the heat exchanger inlet temperature and the set temperature. When the ethylene glycol level is low, the high-pressure pump 105, low-pressure pump 104, and the ethylene glycol pump can be shut down. When the ethylene glycol level is high, a liquid ammonia leak warning can be displayed.

[0053] In some embodiments, the ethylene glycol pump includes: a first ethylene glycol pump and a second ethylene glycol pump;

[0054] The input terminals of the first ethylene glycol pump and the second ethylene glycol pump are connected to each other, and their output terminals are also connected to each other, forming a first circuit;

[0055] Both the heater and the cooler are connected to the first heat exchanger 106 through the first circuit.

[0056] Understandably, the outlets of the first and second ethylene glycol pumps are connected to the heater and cooler, and pressure sensors are installed between the first and second ethylene glycol pumps and the heater and cooler. These pressure sensors can be used to monitor the ethylene glycol outlet pressure, trigger an alarm when the ethylene glycol outlet pressure is high, and control the high-pressure pump 105, the low-pressure pump 104, and the ethylene glycol pump to stop working.

[0057] In some embodiments, the automatic control system for ammonia fuel supply further includes: a first pressure sensor disposed between the first circuit and the heater and the cooler;

[0058] The controller is also configured to receive the ethylene glycol outlet pressure collected by the first pressure sensor, and control the high-pressure pump 105, the low-pressure pump 104, the first ethylene glycol pump and the second ethylene glycol pump to stop working when the ethylene glycol outlet pressure is greater than the first target pressure threshold.

[0059] It is understandable that when the ethylene glycol outlet pressure is high, it indicates that there may be a malfunction in the ethylene glycol heat exchange system. In this case, it is necessary to control the high-pressure pump 105, the low-pressure pump 104, the first ethylene glycol pump and the second ethylene glycol pump to stop working in order to avoid the temperature of the supplied ammonia fuel not meeting the requirements.

[0060] In some embodiments, a filling valve is provided on the pipeline between the unloading arm 101 and the liquid ammonia storage tank 103, and a gas phase valve is provided on the pipeline between the unloading compressor 102 and the gas outlet of the liquid ammonia storage tank 103.

[0061] The controller is also used to control the opening of the filling valve and the gas phase pipe valve in the unloading mode.

[0062] Understandably, in unloading mode, the controller controls the opening of the filling valve and the gas phase pipe valve, and the unloading arm 101 begins to fill the liquid ammonia storage tank 103 with liquid ammonia fuel. At the same time, it ensures that the gas pressure inside the liquid ammonia storage tank 103 meets the requirements, so that the liquid ammonia fuel can be successfully filled into the liquid ammonia storage tank 103.

[0063] In some embodiments, the low-pressure pump 104 includes a first low-pressure pump 104 and a second low-pressure pump 104, and the high-pressure pump 105 includes a first high-pressure pump 105 and a second high-pressure pump 105; the input terminals of the first low-pressure pump 104 and the second low-pressure pump 104 are interconnected and their output terminals are interconnected to form a second circuit, and the input terminals of the first high-pressure pump 105 and the second high-pressure pump 105 are interconnected and their output terminals are interconnected to form a third circuit;

[0064] The second circuit, the third circuit, the first heat exchanger 106 and the dual filter 107 are connected in sequence and then connected to the liquid ammonia outlet of the liquid ammonia storage tank 103;

[0065] Furthermore, the output of the second circuit is also connected to the input of the first heat exchanger 106 via a bypass reflux valve;

[0066] The controller is also used to control the opening of the filling valve, the outlet valve and the bypass reflux valve after the low-pressure pump 104 is started, and to adjust the liquid ammonia flow rate by controlling the bypass reflux valve.

[0067] Understandably, when the low-pressure pump 104 is turned on in the host computer control interface, the control program automatically starts after the low-pressure pump 104 is started. Figure 2 The liquid ammonia storage tank 103 shown has a top filling valve ESV001 and a tank outlet valve ESV003. The bypass reflux valve PSV001 is then opened to regulate the liquid ammonia flow rate. Ammonia fuel is cooled or heated by heat exchanger E101, with precise temperature control based on the main unit's fuel requirements. The temperature setpoint can be changed and displayed in real-time on the control interface. The ethylene glycol heat exchange system has both heating and cooling modes. The control system automatically compares the heat exchanger inlet temperature with the set temperature and automatically switches modes. The control interface can select and control the high-pressure pump 105, automatically opening the bypass reflux valve.

[0068] In some embodiments, the dual filter 107 includes: a first dual filter 107 and a second dual filter 107;

[0069] The input ends of the first dual filter 107 and the second dual filter 107 are both connected to the output end of the first heat exchanger 106, and the output ends of the first dual filter 107 and the second dual filter 107 are provided with a second pressure sensor.

[0070] The controller is also configured to receive the liquid ammonia pressure difference between the output of the first dual filter 107 and the second dual filter 107 collected by the second pressure sensor, and issue a reminder to replace the filter element of the dual filter 107 when the liquid ammonia pressure difference is greater than the second target pressure threshold.

[0071] It is understood that if the liquid ammonia pressure difference is greater than the second target pressure threshold, either the filter element of the first dual filter 107 or the filter element of the second dual filter 107 may be faulty. In this case, it is necessary to manually identify the faulty filter element and replace it.

[0072] In some embodiments, the automatic control system for ammonia fuel supply further includes: an injector cooling water module consisting of a cooling water tank, a second heat exchanger, and a cooling water pump connected in sequence, the injector cooling water module being used to supply cooling water to the ammonia injector.

[0073] Understandably, the primary purpose of the injector cooling water module is to cool the ammonia injectors when the engine is running in diesel mode. When the engine is running in diesel mode, ammonia injector cooling water circulates from the ammonia injector cooling water buffer tank to the ammonia injectors and then returns to the cooling water buffer tank in a closed loop. Additionally, injector cooling water is used during purging to remove vapors after liquid purging.

[0074] The injector cooling water system is a closed-loop circulating water system with an independent electronic control system. During operation, the injector cooling pump supplies cooling water to the engine according to the control command. During the process, the pressure is controlled by the injector cooling pump and the bypass return flow according to the pressure requirements. The system automatically executes the pressure replenishment and depressurization program of the cooling water tank according to the set value. All remote control valves and pumps in the system can be selected to operate in manual mode and can be manually operated separately on the control interface.

[0075] In some embodiments, the automatic control system for ammonia fuel supply further includes: an ammonia collection tank and a first scrubbing cabinet;

[0076] The input end of the ammonia collection tank is connected to the liquid ammonia storage tank 103 via a vent valve, and the output end of the ammonia collection tank is connected to the first washing cabinet.

[0077] Understandably, when the first washing tank is running, the spray tower sprays fresh water, with the fresh water flow controlled by a control valve, and sensors measuring and reporting the actual flow rate. (Reference) Figure 3 As shown, TIT501 monitors the temperature of the gas-liquid separator tank, and activates the water spray when the temperature is higher than the alarm; PIT501 / 502 control and monitor the pressure of the gas-liquid separator tank respectively; LIT501 monitors the liquid level of the gas-liquid separator tank, and opens Q301 when the liquid level is higher and closes Q301 when the liquid level is lower; LIT502 monitors the liquid level of the washing cabinet, and reminds the user to discharge ammonia water when the alarm is higher than the alarm, and reminds the user to add fresh water when the alarm is lower than the alarm.

[0078] In some embodiments, the automatic control system for ammonia fuel supply further includes: a gas-liquid separator and a second scrubbing tank;

[0079] The input end of the gas-liquid separator is connected to the output end of the low-pressure pump 104, and the output end of the gas-liquid separator is connected to the second washing cabinet.

[0080] Understandably, after fuel switching or emergency shutdown, nitrogen is used to purge the main unit, requiring the collection and treatment of the gas-liquid mixture returning from the main unit. The designed residual liquid collection and treatment system for the ammonia fuel station mainly consists of a gas-liquid separator and an ammonia scrubbing unit. The gas-liquid separator collects the liquid ammonia purged from the first stage of the main unit's operation and uses high-pressure nitrogen to nitrogen-seale it, maintaining its liquid state. At high liquid levels, the liquid ammonia is output to the inlet of high-pressure pump 105 for recycling.

[0081] In some embodiments, the structural design and sensor placement of the automatic control system for ammonia fuel supply are as follows: Figure 2 and Figure 3 As shown below, the functional composition, control logic, and monitoring description of each subsystem are described in detail.

[0082] Ammonia Fuel Refueling and Storage System: The main function of the refueling and storage system is to transfer and safely store ammonia fuel from the refueling station to the storage tank. Its main components include the unloading arm 101, the unloading compressor 102, the ammonia fuel storage tank (i.e., liquid ammonia storage tank 103), solenoid valves, and safety valves. Liquid ammonia is transported by tank truck. After connecting to the unloading arm 101 on-site, the four-way valve of the unloading compressor 102 is switched to unloading mode on the host computer control interface. The bottom refueling valve ESV002 and the vapor phase pipe valve ESV006 of the storage tank are opened, followed by opening the main refueling valves ESV005 and ESV004 of the storage tank. The vapor phase pipe valves of the tank truck remain unobstructed, and the unloading operation is completed by pressurizing the tank truck using the unloading compressor 102.

[0083] The relevant sensors, such as LIT001, PIT001, PIT002, TIT001, TIT002, and TIT003, are displayed in real time on the host computer interface, and a pop-up alarm will be triggered when the range is exceeded. LIT001 is a liquid ammonia storage tank 103 level sensor, providing high, low, higher, and lower level alarms. A high level alarm automatically shuts off the main filling valve ESV004 and the compressor, while a lower level alarm automatically stops the pressure pump. PIT001 is a pressure sensor monitoring the tank pressure, providing high, low, higher, and lower pressure alarms. A higher pressure alarm automatically shuts off the main filling valve, unloading compressor 102, and high / low pressure pump 104, while a lower pressure alarm automatically shuts off high / low pressure pump 104. PIT002 monitors the compressor outlet pressure; a higher pressure alarm automatically stops the compressor to prevent excessive pressure and accidents. TIT is a temperature sensor monitoring the liquid ammonia storage tank 103 temperature, providing high, low, higher, and lower temperature alarms. A higher temperature alarm automatically activates the water spray system.

[0084] Ammonia Fuel Supply System: The ammonia fuel supply system mainly consists of a low-pressure pump 104, a high-pressure pump 105, an electric heater, a heat exchanger, an ethylene glycol pump, a dual filter 107, a bypass valve, and a solenoid valve. Based on the main unit's inlet fuel requirements, the ammonia fuel pressure, temperature, and purity are adjusted to the range specified by the main unit. The power booster equipment is configured with one unit in operation and one in standby; in the event of a failure of one unit, it automatically switches to the standby unit. The low-pressure pump 104 is turned on via the host computer control interface. After the low-pressure pump 104 starts, the control program automatically opens the top filling valve ESV001 and the outlet valve ESV003 of the liquid ammonia storage tank 103, and then opens the bypass return valve PSV001 to regulate the liquid ammonia flow rate. The ammonia fuel is cooled or heated by the heat exchanger E101, with precise temperature control based on the main unit's fuel requirements. The temperature setpoint can be changed and displayed in real time on the control interface. The ethylene glycol heat exchange system has two modes: heating and cooling. The control system automatically compares the heat exchanger inlet temperature with the set temperature and automatically switches modes accordingly. The control interface allows selection of the high-pressure pump 105 and control of its start and stop, and automatically opens the bypass return valve.

[0085] The corresponding sensors of the liquid ammonia conveying and supply system are displayed in real time on the host computer interface, and a pop-up alarm will be triggered when the range is exceeded. High, higher, low, and lower correspond to different logic. PIT011 monitors the outlet pressure of low-pressure pump 104; PIT012 displays the pressure on the control interface and allows setting the outlet pressure of low-pressure pump 104; TIT011 monitors the inlet temperature of high-pressure pump 105; PIT013-PIT001 are the inlet pressure difference of high-pressure fuel pump; PIT014 monitors the outlet pressure of high-pressure pump 105, and fully opens the bypass valve PCV011 when a higher pressure alarm occurs; TIT013 / 014 are temperature sensors at the outlet of the liquid ammonia heat exchanger, used to control and monitor the outlet temperature respectively; DPIT011 is the pressure difference of the dual filter 107, reminding to replace the filter element when a higher pressure alarm occurs; FIT011 is a mass flow meter; TIT015 monitors and controls the ethylene glycol outlet temperature; TIT016 monitors the ethylene glycol return water temperature; PIT015 monitors the ethylene glycol outlet pressure, and automatically stops the high and low pressure pumps 104 and the ethylene glycol pump when a higher pressure alarm occurs. The LS011 monitors the ethylene glycol level. When the level is too low, it stops the high and low pressure pumps 104 and the ethylene glycol pump. When the level is too high, it alerts the host computer interface to a liquid ammonia leak.

[0086] Ammonia Fuel Valve Unit: This unit is equipped with a piping system to safely purge and degas each fuel tank, and to refuel with ammonia after purging. The FVU (Fuel Valve Unit) is used to regulate and ensure system safety, and mainly consists of solenoid valves, filters, flow meters, safety valves, and various sensors. The valve unit is divided into normally closed and normally open valves. Before each ammonia supply, a leak test is required for the valve unit. Upon receiving a signal from the control system, the corresponding valve is closed. The test is passed if the pressure does not exceed the set value within a specified time. The control interface has a separate debugging interface. In debugging mode, the valves can be manually controlled, and each valve can be individually opened and closed. The control interface also needs to display the open / closed status of each valve. When the pneumatic valve position feedback is inconsistent with the command, the control system triggers a valve fault alarm, causing the FVU to enter its initial state.

[0087] PIT021 / 022 monitor the inlet and outlet pressures of the supply pipe, respectively; TIT021 / 022 monitor the inlet temperature of the supply pipe and return pipe, respectively; when the system is running normally, all valves are in the initial state. Before each ammonia supply, the system will perform a leak test. Q102 / 103 / 104 are closed. If the pressure change of PIT2601 does not exceed the set value within a specified time, the system is considered to have good sealing performance. Then Q102 / 103 is opened to start ammonia supply; when the main unit is shut down in emergency mode in ammonia fuel mode, or when switching from ammonia fuel to other fuels, Q108 / 110 is opened and Q109 is closed, and the nitrogen system starts to purge the FVU pipeline and the main unit; when the main unit is running in diesel mode, Q118 / 119 / 122 / 123 are opened, and the cooling water system cools the ammonia injector.

[0088] Nitrogen Supply System: In the event of an emergency stop of the engine in ammonia fuel mode, or a sudden engine shutdown during ammonia fuel mode operation, measures should be taken to purge the exhaust pipe before restarting the engine. The purge gas should be properly treated. The purpose of the designed inert gas supply system is to provide inert gas for the ammonia storage and supply system. When the main engine switches from ammonia fuel mode to fuel oil mode or vice versa, the nitrogen purging of the main engine and supply pipeline is mainly accomplished by controlling different valve groups in the FVU.

[0089] The system provided by this invention has two nitrogen supply devices, located in the ammonia station area and the valve unit area respectively. The nitrogen supply system in the ammonia station area needs to monitor pressure, while the valve unit system, in addition to pressure monitoring, also needs to adjust the pressure value and nitrogen heater according to the host requirements, and open and close different valves according to different needs. When a strong nitrogen purging command is received, Q201 is opened to supply nitrogen until the strong nitrogen purging command is withdrawn; when a weak nitrogen supply command is received, Q202 is opened to supply weak nitrogen until the weak nitrogen purging command is withdrawn; when a coolant tank pressurization command is received, Q203 is opened to supply nitrogen until the coolant tank pressurization command is withdrawn; when an engine nitrogen supply command is received, Q204 is opened to supply nitrogen until the engine nitrogen supply command is withdrawn. TIT031 monitors the nitrogen purging temperature, and PIT031 / 032 monitor the FVU nitrogen supply pressure and the ammonia station area nitrogen supply pressure, respectively.

[0090] Ammonia Injector Cooling Water System: The designed ammonia injector cooling water system (AICWS) includes an ammonia injector cooling water buffer tank with a heat exchanger (cooling element) and an ammonia injector cooling water supply pump. It, along with the interface valves, piping system, and fuel injection system, constitutes the ammonia injector cooling water system. The primary purpose of the ammonia injector cooling water system is to cool the ammonia injectors when the engine is running in diesel mode. When the engine is running in diesel mode, ammonia injector cooling water circulates from the ammonia injector cooling water buffer tank to the ammonia injectors and then returns to the cooling water buffer tank in a closed loop. Additionally, injector cooling water is used during purging to remove vapors after liquid purging.

[0091] The injector cooling water system is a closed-loop circulating water system with an independent electronic control system. During operation, the injector cooling pump supplies cooling water to the engine according to control commands. Pressure is controlled based on pressure requirements through the injector cooling pump and bypass return flow. The system automatically executes the coolant tank pressure replenishment and relief procedures according to set values. All remote-controlled valves and pumps within the system can be manually operated via the control interface. LIT041 monitors the coolant tank level; if a high / low level alarm occurs, the system automatically stops. PIT041 monitors the coolant tank pressure; if a high / low pressure alarm occurs, the system automatically stops. TIT041 monitors the coolant tank temperature. TIT042 monitors the water cooler outlet temperature. PIT042 monitors the system outlet pressure. FS041 monitors the coolant flow rate and automatically stops the system when a lower flow rate alarm occurs.

[0092] Ammonia Residual Liquid Collection and Treatment System: After fuel switching or emergency shutdown, nitrogen is used to purge the main unit. The system requires the collection and treatment of the gas-liquid mixture returning from the main unit. The designed ammonia fuel station residual liquid collection and treatment system mainly consists of a gas-liquid separator and an ammonia scrubbing unit. The gas-liquid separator collects the liquid ammonia purged from the first stage of the main unit purge and uses high-pressure nitrogen to nitrogen-seale it, maintaining its liquid state. At high liquid levels, the liquid ammonia is output to the inlet of high-pressure pump 105 for recycling.

[0093] The gas-liquid separator mainly controls the Q301 liquid ammonia output valve, the Q302 nitrogen replenishment valve, and the Q303 ammonia vent valve. The ammonia scrubbing unit consists of two scrubbing containers, three ammonia pumps, and two heat exchangers. During operation, the ammonia-containing gas to be scrubbed enters, triggering a flow switch and activating the scrubbing unit. The gas-liquid separator has two functions: nitrogen pressurization and pressure relief via the vent valves. When the pressure exceeds the upper limit or falls below the lower limit, the program is automatically executed according to the set values. The scrubbing zone consists of scrubbing containers, ammonia pumps, and heat exchangers. During operation, a spray tower sprays fresh water, with the fresh water flow controlled by a control valve and the actual flow measured and fed back by sensors. TIT501 monitors the temperature of the gas-liquid separator; if the temperature is too high, the water spray will be activated. PIT501 and PIT502 control and monitor the pressure of the gas-liquid separator, respectively. LIT501 monitors the liquid level of the gas-liquid separator; if the liquid level is too high, Q301 will be turned on, and if the liquid level is too low, Q301 will be turned off. LIT502 monitors the liquid level of the washing cabinet; if the liquid level is too high, the alarm will remind the user to discharge ammonia water, and if the liquid level is too low, the alarm will remind the user to add fresh water.

[0094] PLC and Host Computer Introduction: Based on the overall design scheme and control strategy of the ammonia fuel supply system, hardware design and software selection were carried out. The TIA Portol software was used to design the PLC automatic control system; therefore, the Siemens S7 series PLC was selected. The corresponding S7-1500 PLC was selected according to the number of input / output points, memory capacity, and functions. Additional AI, AQ, DI, and DQ signal input / output modules were added. The specific hardware configuration is shown in the attached diagram. The PLC program mainly realizes communication control with the HMI, control of various valves, components, and areas of the ammonia fuel supply system, and equipment fault alarms. WinCC software and a desktop computer were used to control and monitor the overall supply system. The overall operating status of the supply system was fed back to the HMI interface in real time through variables. Operators could monitor the supply system status in real time through the HMI and issue commands to control the supply system. The supply system could monitor and record alarms in real time, and stop system operation when necessary, facilitating subsequent equipment maintenance and repair. The specific HMI interface is shown in the attached diagram.

[0095] Due to the unique physicochemical properties of ammonia, existing supply systems for diesel, LNG, and methanol cannot be used. In accordance with national standards and classification society regulations, a supply system suitable for ammonia fuel has been developed to ensure the stable storage and safe transportation of ammonia fuel. Furthermore, a fully automated control system for the supply system has been developed based on PLC and WinCC, covering all aspects of fuel filling, storage, transportation, and supply. This system can monitor in real time and automatically adjust the temperature, flow rate, and pressure of the fuel according to the host's requirements, ensuring the stability and efficiency of the ammonia fuel system.

[0096] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0097] The automatic control system for ammonia fuel supply provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An automatic control system for ammonia fuel supply, characterized in that, include: Unloading arm, unloading compressor, liquid ammonia storage tank, low-pressure pump, high-pressure pump, first heat exchanger, dual filter and controller; The unloading arm is connected to the filling port of the liquid ammonia storage tank, and the unloading compressor is connected to the gas outlet of the liquid ammonia storage tank. The low-pressure pump, the high-pressure pump, the first heat exchanger, and the dual filter are sequentially connected to the liquid ammonia outlet of the liquid ammonia storage tank via pipelines, and an outlet valve is provided at the liquid ammonia outlet of the liquid ammonia storage tank. The controller is used to control the operating modes of the low-pressure pump, the high-pressure pump, the first heat exchanger, and the dual filter to adjust the pressure, temperature, and purity of the output ammonia fuel to the target range. The automatic control system for ammonia fuel supply also includes: an ethylene glycol expansion tank, an ethylene glycol pump, a heater, a cooler, and a chiller unit; Both the heater and the cooler are connected to the first heat exchanger via the ethylene glycol pump, and the ethylene glycol expansion tank is connected to the first heat exchanger. The chiller unit is connected to the cooler; The ethylene glycol pump includes: a first ethylene glycol pump and a second ethylene glycol pump; The input terminals of the first ethylene glycol pump and the second ethylene glycol pump are connected to each other, and their output terminals are also connected to each other, forming a first circuit; Both the heater and the cooler are connected to the first heat exchanger through the first circuit; The automatic control system for ammonia fuel supply further includes: a first pressure sensor disposed between the first circuit and the heater and the cooler; The controller is also configured to receive the ethylene glycol outlet pressure collected by the first pressure sensor, and control the high-pressure pump, the low-pressure pump, the first ethylene glycol pump and the second ethylene glycol pump to stop working when the ethylene glycol outlet pressure is greater than the first target pressure threshold.

2. The automatic control system for ammonia fuel supply according to claim 1, characterized in that, A filling valve is installed on the pipeline between the unloading arm and the liquid ammonia storage tank, and a gas phase valve is installed on the pipeline between the unloading compressor and the gas outlet of the liquid ammonia storage tank. The controller is also used to control the opening of the filling valve and the gas phase pipe valve in the unloading mode.

3. The automatic control system for ammonia fuel supply according to claim 2, characterized in that, The low-pressure pump includes a first low-pressure pump and a second low-pressure pump, and the high-pressure pump includes a first high-pressure pump and a second high-pressure pump; the input terminals of the first low-pressure pump and the second low-pressure pump are interconnected and their output terminals are interconnected to form a second circuit, and the input terminals of the first high-pressure pump and the second high-pressure pump are interconnected and their output terminals are interconnected to form a third circuit. The second circuit, the third circuit, the first heat exchanger, and the dual filter are connected in sequence and then connected to the liquid ammonia outlet of the liquid ammonia storage tank. Furthermore, the output of the second circuit is also connected to the input of the first heat exchanger via a bypass reflux valve; The controller is also used to control the opening of the filling valve, the outlet valve and the bypass reflux valve after controlling the low-pressure pump to start, and to adjust the liquid ammonia flow rate by controlling the bypass reflux valve.

4. The automatic control system for ammonia fuel supply according to claim 1, characterized in that, The dual filter includes: a first dual filter and a second dual filter; The input ends of the first dual filter and the second dual filter are both connected to the output end of the first heat exchanger, and the output ends of the first dual filter and the second dual filter are provided with a second pressure sensor. The controller is also configured to receive the liquid ammonia pressure difference between the output of the first dual filter and the second dual filter collected by the second pressure sensor, and issue a reminder to replace the dual filter element when the liquid ammonia pressure difference is greater than the second target pressure threshold.

5. The automatic control system for ammonia fuel supply according to claim 1, characterized in that, Also includes: The injector cooling water module consists of a cooling water tank, a second heat exchanger, and a cooling water pump connected in sequence. The injector cooling water module is used to provide cooling water to the ammonia injector.

6. The automatic control system for ammonia fuel supply according to claim 1, characterized in that, Also includes: Ammonia collection tank and first washing cabinet; The input end of the ammonia collection tank is connected to the liquid ammonia storage tank via a vent valve, and the output end of the ammonia collection tank is connected to the first washing cabinet.

7. The automatic control system for ammonia fuel supply according to any one of claims 1-6, characterized in that, It also includes: a gas-liquid separator and a second washing cabinet; The input end of the gas-liquid separator is connected to the output end of the low-pressure pump, and the output end of the gas-liquid separator is connected to the second washing cabinet.

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