A marine methanol fuel supply system and a supply method

Abstract

The application discloses a kind of marine methanol fuel supply system and supply method, belong to marine fuel supply technical field.The marine methanol fuel supply system includes methanol storage tank, hydraulic submerged liquid pump, heat exchange unit;The pump body of hydraulic submerged liquid pump is located in the tank body of methanol storage tank and is installed at oil suction well, is driven by hydraulic oil;Heat exchange unit uses water and ethylene glycol mixture as circulating heat exchange medium, the temperature of water and ethylene glycol mixture after heat exchange through second heat exchanger is 5-15 ℃ higher than the temperature of water and ethylene glycol mixture after heat exchange through first heat exchanger.The application is applied to marine methanol fuel supply aspect, solve the technical problem that the supply system of existing marine methanol fuel is used for meeting the use requirement and adopts daily use tank and expansion tank and other structures, seriously occupies marine space, with the characteristics of saving marine space, while being able to guarantee the methanol pressure and temperature stability of supply main engine.

Description

Technical Field

[0001] This invention belongs to the field of marine fuel supply technology, and particularly relates to a marine methanol fuel supply system and supply method. Background Technology

[0002] Energy is the material foundation for human survival and development, and a crucial guarantee for the economic and social development of all countries. Currently, finding suitable alternative energy sources has become an important strategy for solving my country's energy development problems. Methanol is a clean, efficient, and low-carbon liquid fuel. Using methanol as fuel for ship engines can greatly alleviate my country's dependence on foreign energy sources and play a positive role in achieving my country's dual-carbon goals.

[0003] Chinese patent CN116816562A discloses a methanol fuel supply system for ships, including a methanol supply module, a nitrogen purging / degradation module, a thermostatic medium supply module, and a venting module. The methanol supply module includes a first methanol remote control valve, a methanol filter, a first normally open methanol ball valve, a methanol booster pump, a second normally open methanol ball valve, a methanol check valve, a first methanol shut-off valve, a methanol flow meter, a second methanol shut-off valve, a methanol thermostat, a fourth methanol shut-off valve, a double-isolation double-venting valve, and a second methanol remote control valve, all connected in series with a methanol daily storage tank. The nitrogen purging / degradation module includes a methanol pipeline purging line, a methanol thermostat purging line, and a double-isolation double-venting valve purging line. The thermostatic medium supply module includes a thermostatic medium expansion tank and a primary thermostatic medium supply line, an intermediate thermostat, and a secondary thermostatic medium supply line connected in series between the outlet of the thermostatic medium expansion tank and the thermostatic medium inlet of the methanol thermostat. The venting module is connected to both the methanol supply module and the nitrogen purging / degradation module. The ship's methanol fuel supply system is characterized by easy control, low failure rate, and more agile information feedback.

[0004] However, due to limited space on board, the aforementioned marine methanol fuel supply system adopted structures such as day tanks and expansion tanks to meet usage requirements, which seriously occupied the space on board. Summary of the Invention

[0005] Details of one or more embodiments of the present invention are set forth in the following drawings and description to make other features, objects and advantages of the present application more readily apparent.

[0006] This invention proposes a marine methanol fuel supply system and method, which solves the technical problem that existing marine methanol fuel supply systems use structures such as day tanks and expansion tanks to meet usage requirements, which seriously occupy marine space. It has the characteristics of saving marine space and ensuring stable methanol pressure and temperature supplied to the main engine.

[0007] This invention discloses a marine methanol fuel supply system, including a methanol storage tank, a hydraulic submersible pump, and a heat exchange unit. The methanol storage tank has a suction well at its bottom, and the bottom of the tank has a certain slope that converges towards the suction well. The hydraulic submersible pump is located inside the methanol storage tank and installed at the suction well, driven by hydraulic oil. The heat exchange unit uses a water and ethylene glycol mixture as the circulating heat exchange medium and includes a first heat exchanger and a second heat exchanger. In the first heat exchanger, part of the heat from the water and ethylene glycol mixture is transferred to the methanol transported to the heat exchange unit by the hydraulic submersible pump. In the second heat exchanger, part of the heat from the hot fluid is transferred to the water and ethylene glycol mixture that has been heated by the first heat exchanger. The temperature of the water and ethylene glycol mixture after heat exchange by the second heat exchanger is 5-15°C higher than the temperature of the water and ethylene glycol mixture after heat exchange by the first heat exchanger.

[0008] In some embodiments, the hydraulic submersible pump is connected to a hydraulic pump station on board via hydraulic oil pipes; the hydraulic submersible pump delivers methanol from the methanol storage tank to the first heat exchanger in the heat exchange unit for heat exchange via a delivery pipeline, and returns the methanol that has been heat-exchanged by the heat exchange unit to the methanol storage tank via a return pipeline; the return pipeline is equipped with a regulating valve.

[0009] In some embodiments, a variable frequency motor connected to the hydraulic submersible pump is also included.

[0010] In some embodiments, the heat exchange unit further includes a water-glycol pump that pressurizes the water and ethylene glycol mixture, and a filter connected to the methanol outlet of the first heat exchanger, the filter comprising two filters connected in parallel.

[0011] In some embodiments, the heat fluid in the second heat exchanger is low-temperature fresh water from the ship.

[0012] In some embodiments, a fuel valve assembly is also included that connects the heat exchange unit to the main unit, the fuel valve assembly being connected to the methanol outlet of the first heat exchanger via the filter.

[0013] In some embodiments, a methanol release chamber and an oil release chamber are also included; the methanol release chamber is connected to the methanol storage tank, the heat exchange unit, and the fuel valve group via pipelines; the oil release chamber is connected to the fuel valve group via pipelines.

[0014] In some embodiments, a first nitrogen buffer tank and a second nitrogen buffer tank are also included; the first nitrogen buffer tank is connected to the methanol storage tank, the methanol venting chamber and the oil venting chamber via pipelines; the second nitrogen buffer tank is connected to the heat exchange unit, the fuel valve group and the main unit via pipelines.

[0015] Another aspect of the present invention provides a method for supplying methanol fuel to a marine methanol fuel supply system as described in any of the above technical solutions, comprising: under the drive of hydraulic oil, the hydraulic submersible pump placed in the tank body of the methanol storage tank adjusts the methanol supply pressure to 13 bar, and transfers the methanol to the first heat exchanger in the heat exchange unit for heat exchange, wherein the temperature of the methanol after heat exchange by the first heat exchanger is any value within the range of 25-50°C.

[0016] In some embodiments, the method further includes a step of stabilizing the methanol supply pressure: when the methanol supply pressure is too high, the hydraulic oil flow rate is reduced by a variable frequency motor, and the impeller speed in the pump body is reduced, thereby reducing the methanol supply pressure; when the methanol supply pressure is too low, the hydraulic oil flow rate is increased by a variable frequency motor, and the impeller speed in the pump body is increased, thereby increasing the methanol supply pressure; and / or when the methanol supply pressure is too high, the opening of the regulating valve is increased, and more methanol flows back, thereby reducing the methanol supply pressure; when the methanol supply pressure is too low, the opening of the regulating valve is decreased, and less methanol flows back, thereby increasing the methanol supply pressure.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention provides a marine methanol fuel supply system. By improving the structure of the methanol storage tank, a hydraulic submersible pump is built into the methanol storage tank, eliminating the need for a day tank while ensuring smooth methanol delivery and saving marine space. By improving the structure of the heat exchange unit, a mixture of water and ethylene glycol is used as the circulating heat exchange medium. At the same time, by strictly controlling the temperature difference of the water and ethylene glycol mixture after heat exchange through two heat exchangers, the use of an expansion tank is eliminated while ensuring heat exchange safety, further saving marine space.

[0019] Another aspect of the present invention provides a method for supplying methanol fuel for marine use, which meets the supply demand while reducing equipment energy consumption and operating noise, and features high efficiency, energy saving and low cost. Attached Figure Description

[0020] 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:

[0021] Figure 1 This is a schematic diagram of the structure of a marine methanol fuel supply system provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the installation structure of the hydraulic submersible pump provided in an embodiment of the present invention;

[0023] Attached Figure Descriptions: 1. Methanol Storage Tank; 101. Suction Well; 2. Hydraulic Submersible Pump; 3. Heat Exchange Unit; 301. First Heat Exchanger; 302. Second Heat Exchanger; 303. Water Glycol Pump; 304. Filter; 4. Fuel Valve Assembly; 5. Main Unit; 6. Methanol Release Chamber; 7. Oil Release Chamber; 801. First Nitrogen Buffer Tank; 802. Second Nitrogen Buffer Tank; 9. Regulating Valve; 10. Hydraulic Oil Pipeline; 11. Delivery Pipeline; 12. Return Pipeline; 13. Hydraulic Pump Station. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0025] Obviously, the accompanying drawings described below are merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0026] In this invention, the reference to "embodiment" means that a specific 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 in 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 in this invention may be combined with other embodiments without conflict.

[0027] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," "an," "the," and similar words used in this invention do not indicate quantity limitation and may indicate singular or plural. The terms "comprising," "including," "having," and any variations thereof used in this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms "connected," "linked," "coupled," and similar words used in this invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "A plurality" in this invention refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships may exist; for example, "A and / or B" can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects have an "or" relationship. The terms "first," "second," and "third" used in this invention are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0028] This invention provides a marine methanol fuel supply system. Figure 1 This is a schematic diagram of a marine methanol fuel supply system according to an embodiment of the present invention. (Reference) Figure 1As shown, the marine methanol fuel supply system includes a methanol storage tank 1, a hydraulic submersible pump 2, and a heat exchange unit 3. The bottom of the methanol storage tank 1 has an oil suction well 101, and the bottom of the tank has a certain slope that converges towards the oil suction well 101. The hydraulic submersible pump 2 is located inside the methanol storage tank 1 and installed at the oil suction well 101, driven by hydraulic oil. The heat exchange unit 3 uses a mixture of water and ethylene glycol as the circulating heat exchange medium, and includes a first heat exchanger 301 and a second heat exchanger 302. In the first heat exchanger 301, part of the heat from the water and ethylene glycol mixture is transferred to the methanol transported to the heat exchange unit 3 by the hydraulic submersible pump 2. In the second heat exchanger 302, part of the heat from the hot fluid is transferred to the water and ethylene glycol mixture that has been heated by the first heat exchanger 301. The temperature of the water and ethylene glycol mixture after heat exchange by the second heat exchanger 302 is 5-15°C higher than the temperature of the water and ethylene glycol mixture after heat exchange by the first heat exchanger 301. The system includes a methanol storage tank 1 for storing methanol, and a hydraulic submersible pump 2 located inside the tank. Its main function is to transfer methanol from the tank to the heat exchange unit 3, ensuring it meets the supply pressure requirements of the main engine 5. The heat exchange unit 3 is connected to the methanol storage tank 1 via pipelines and primarily ensures the methanol supply temperature and accuracy required by the main engine 5. The first heat exchanger 301 in the heat exchange unit 3 provides heat to the methanol, while the second heat exchanger provides heat to the water and ethylene glycol mixture (preferably in a 1:1 ratio). This marine methanol fuel supply system, through improvements to the structure of the methanol storage tank 1, integrates the hydraulic submersible pump 2 within the tank, eliminating the need for a day tank while ensuring smooth methanol delivery and saving marine space. Furthermore, improvements to the heat exchange unit 3 limit the use of a water and ethylene glycol mixture as the circulating heat exchange medium. By strictly controlling the temperature difference between the water and ethylene glycol mixture after heat exchange through the two heat exchangers, the system eliminates the need for an expansion tank while ensuring heat exchange safety, further saving marine space. In addition, the design of the heat exchange unit 3 of the ship's methanol fuel supply system replaces the supply unit, reducing the size of the core skid and lowering equipment energy consumption.

[0029] It should be noted that, according to classification society regulations, methanol storage tank 1 is essential on board, while methanol day tank is not. However, in order to supply methanol to heat exchange unit 3 under suitable pressure, existing technologies require an external methanol transfer pump to pump methanol from the storage tank to the day tank, and then to the heat exchange unit 3 via a methanol supply pump in the supply unit. Therefore, existing marine methanol fuel supply systems often equip both the day tank and the methanol supply pump on the hull, resulting in space occupation. This technical solution uses a hydraulic submersible pump 2 installed inside the methanol storage tank 1 as a methanol transfer pump to pressurize the methanol and transfer it to the heat exchange unit 3. In the heat exchange unit 3, the methanol fuel exchanges heat with the ship's heat source and finally enters the fuel valve group 4 to meet the supply requirements. The hydraulic submersible pump 2 is driven by hydraulic oil, and its structure built into the methanol storage tank 1 is entirely mechanical, without any electrical components, avoiding the danger caused by methanol coming into contact with electrical components. Therefore, it can be built-in. Meanwhile, the technical solution of this invention, through improvements to the structure of methanol storage tank 1, enables the hydraulic submersible pump 2, built into the tank body, to pressurize and transport methanol. This ensures a normal supply of methanol while eliminating the use of day tanks, saving shipboard space, and reducing equipment costs. Specifically, as... Figure 2As shown, the bottom of the methanol storage tank 1 is equipped with an oil suction well 101 with a certain slope to facilitate the gravity flow of methanol to the vicinity of the oil suction well 101, which is then used to transport methanol via a hydraulic submersible pump 2 mounted on a bracket at the oil suction well 101. To facilitate the installation and maintenance of the hydraulic submersible pump 2, a manhole is also provided on the top of the methanol storage tank 1. Furthermore, this invention eliminates the use of a methanol supply pump, avoiding the overheating problem caused by a magnetic centrifugal pump and reducing operating noise. Simultaneously, the use of the hydraulic submersible pump 2 in this invention ensures supply pressure while preventing cavitation, and there are no strict requirements on the height difference between modules. In existing heat exchange units 3, to avoid dangerous situations caused by rapid expansion due to a large temperature difference before and after heat exchange, an expansion tank is often required within the heat exchange unit 3, further reducing the space within the ship's hull. This invention improves the structure of heat exchange unit 3, limiting the circulating heat exchange medium to a mixture of water and ethylene glycol. It also strictly controls the temperature difference between the water and ethylene glycol mixture passing through the two heat exchangers, preferably at 10°C. At this temperature, the lower temperature difference results in a smaller expansion rate, avoiding the expansion risk caused by drastic volume changes in the water and ethylene glycol mixture before and after heat exchange, and saving space occupied by the expansion tank. Furthermore, this temperature difference design is a crucial indicator that comprehensively considers various system operating parameters, including the flow rate of the heat exchange medium, heat exchange requirements, and supply requirements. It ensures that heat exchange and heating requirements can be met by adjusting the corresponding flow rates of each heat exchange medium, without creating operational risks due to the absence of an expansion tank. To further ensure safety, redundant pipe diameters within heat exchange unit 3 can be added to meet expansion needs, further saving space on board the ship.

[0030] In some embodiments, the hydraulic submersible pump 2 is connected to the hydraulic pump station 13 on board via hydraulic oil pipe 10; the hydraulic submersible pump 2 transports methanol from the methanol storage tank 1 to the first heat exchanger 301 in the heat exchange unit 3 for heat exchange via the delivery pipe 11, and returns the methanol that has been heat-exchanged by the heat exchange unit 3 to the methanol storage tank 1 via the return pipe 12; the return pipe 12 is equipped with a regulating valve 9. In this embodiment, the hydraulic submersible pump 2 and the regulating valve 9 on the return pipe 12 can cooperate with each other to stabilize the methanol fuel pressure and meet the requirements of the main engine 5. The specific adjustment process includes: 1) driving the methanol transfer pump (i.e., the hydraulic submersible pump 2) with hydraulic oil from the hydraulic pump station 13 to obtain a certain head, and changing the impeller speed in the pump body by adjusting the pressure and flow rate of the hydraulic oil, thereby changing the head of the methanol transfer pump and thus adjusting the methanol pressure. Simultaneously, the methanol supply pressure can be controlled by the regulating valve 9 of the return pipeline 12: when the methanol pressure is too high, the opening of the regulating valve 9 is increased, resulting in more methanol returning, thereby reducing the methanol supply pressure; when the methanol pressure is too low, the opening of the regulating valve 9 is decreased, resulting in less methanol returning, thereby increasing the methanol supply pressure. The methanol transfer pump and the regulating valve 9 can cooperate to achieve dual control to ensure the methanol pressure and temperature. In this embodiment, the heat exchange unit 3 and the methanol storage tank 1 are connected by a pipeline, which includes a delivery pipeline 11 that transports methanol from the tank of the methanol storage tank 1 to the heat exchange unit 3, and a return pipeline 12 that returns the methanol that has been heated by the heat exchange unit 3 to the tank of the methanol storage tank 1. The return pipeline 12 is equipped with a regulating valve 9, which regulates the flow rate of methanol returning from the heat exchange unit 3 to ensure stable methanol pressure. It should be noted that, since the vertical sections of the hydraulic oil pipes 10 and the delivery pipes 11 built into the methanol storage tank 1 are relatively long, they are prone to shaking when the ship hull sways, and are difficult to install. To avoid this problem, in a preferred embodiment, the hydraulic oil pipes 10 and the delivery pipes 11 built into the methanol storage tank 1 are installed in sections, with each section connected by a flange, effectively avoiding installation difficulties. At the same time, flange supports are welded and fixed on the inner wall of the methanol storage tank 1 and secured below the flanges, effectively preventing the pipes from shaking or even breaking.

[0031] To further ensure the stability of methanol supply pressure, a variable frequency motor connected to the hydraulic submersible pump 2 is also included. When the methanol pressure is too high, the variable frequency motor can reduce the hydraulic oil flow rate and the pump speed, thereby reducing the methanol supply pressure; when the methanol pressure is too low, the variable frequency motor can increase the hydraulic oil flow rate and the pump speed, thereby increasing the methanol supply pressure.

[0032] The installation structure diagram of hydraulic submersible pump 2 is shown below. Figure 2As shown, an oil suction well 101 is installed at the bottom of the methanol storage tank 1. The pump body of the hydraulic submersible pump 2 is installed at the oil suction well 101 and fixed by a bracket. The pump is driven by hydraulic oil. The hydraulic oil pipe 10 passes through the top of the methanol storage tank 1 and connects to the pump body. Then, the hydraulic oil is supplied with a fixed pressure and flow rate by the hydraulic pump station 13 equipped on the ship, thereby driving the impeller inside the pump body to rotate. The methanol in the methanol storage tank 1 is transported to the heat exchange unit 3 through the delivery pipeline 11. Since the hydraulic oil maintains a fixed pressure and flow rate, the methanol supply pressure can also be kept stable. Moreover, the hydraulic submersible pump 2 is equipped with a variable frequency motor, and the return pipeline 12 is also equipped with a regulating valve 9. The pressure stability can be ensured through dual control by the variable frequency motor and the regulating valve 9. The hydraulic oil pipe 10 and the delivery pipeline 11 are fixed by the support structure on the wall of the methanol storage tank 1. Due to the properties of methanol, electrical structures in contact with methanol must be explosion-proof. This means that centrifugal pumps, volumetric pumps, etc., cannot be built into the methanol storage tank 1. However, the hydraulic submersible pump 2 is driven by hydraulic oil, and the structures built into the methanol storage tank 1 are all mechanical structures without electrical structures, so it can be built into the tank.

[0033] In some embodiments, the heat exchange unit 3 further includes a water-ethylene glycol pump 303 that pressurizes the water and ethylene glycol mixture, and a filter 304 connected to the methanol outlet of the first heat exchanger 301. The filter 304 includes two filters 304 connected in parallel. The water-ethylene glycol pump 303 pressurizes the water and ethylene glycol mixture, ensuring sufficient pressure for complete internal circulation. By controlling the flow rate of the ship's low-temperature fresh water, a fixed heat exchange is provided, ensuring a fixed water-ethylene glycol circulation temperature and thus a stable methanol temperature. The filter 304 filters impurities from the methanol. This embodiment further specifies that the filter 304 is a parallel dual filter, with one side working and the other on standby. When one side is blocked, it can be directly switched to the other side, ensuring efficient operation of the entire system. In some embodiments, the heat fluid of the second heat exchanger 302 is the ship's low-temperature fresh water, a resource abundant on board, thus achieving full utilization of ship resources.

[0034] Furthermore, it also includes a fuel valve assembly 4 connecting the heat exchange unit 3 and the main unit 5. The fuel valve assembly 4 is connected to the methanol outlet of the first heat exchanger 301 through a filter 304. The fuel valve assembly 4 includes various valves, switches, etc. The fuel valve assembly 4 is connected to the heat exchange unit 3 and the main unit 5 through pipelines. Methanol reaches the main unit 5 after passing through the fuel valve assembly 4. The methanol is pressurized to 13 bar by the hydraulic submersible pump 2. The methanol temperature is controlled at 25-50°C by the heat exchange unit 3. The fuel valve assembly 4 controls and detects fuel temperature, pressure, etc.

[0035] In some embodiments, a methanol venting tank 6 and an oil venting tank 7 are also included. The methanol venting tank 6 is connected to the methanol storage tank 1, the heat exchange unit 3, and the fuel valve assembly 4 via pipelines. The oil venting tank 7 is connected to the fuel valve assembly 4 via pipelines. The methanol venting tank 6 collects residual methanol in the system, and the oil venting tank 7 collects fuel oil returning from the main engine 5. By adding the oil venting tank 7 to the system, the traditional day-use compartment design is eliminated, avoiding the day-use compartment occupying a large amount of hull space. Specifically, the oil venting tank 7 is connected to the fuel valve assembly 4 via pipelines. The fuel oil returning from the main engine 5 is filtered by a conical filter and then collected by the oil venting tank 7 through valves. The conical filter and valves in this embodiment are commonly used devices in the art, and their specific structure and principle will not be described in detail in this embodiment.

[0036] The system further includes a first nitrogen buffer tank 801 and a second nitrogen buffer tank 802. The first nitrogen buffer tank 801 is connected to the methanol storage tank 1, the methanol venting chamber 6, and the oil venting chamber 7 via pipelines. The second nitrogen buffer tank 802 is connected to the heat exchange unit 3, the fuel valve group 4, and the main engine 5 via pipelines. Specifically, the first nitrogen buffer tank 801 is connected to the methanol storage tank 1, the methanol venting chamber 6, and the oil venting chamber 7 via pipelines, and the nitrogen injection into the methanol storage tank 1, the methanol venting chamber 6, and the oil venting chamber 7 is controlled by control valves to ensure the inerting of the connecting pipelines and chambers. The second nitrogen buffer tank 802 is connected to the heat exchange unit 3, the fuel valve group 4, and the main engine 5 via pipelines, and the nitrogen purging and inerting of the heat exchange unit 3, the fuel valve group 4, and the main engine 5 is controlled by control valves. This marine methanol supply system can provide methanol fuel with specific flow rates, temperatures, pressures, and precision to the methanol main engine 5, ensuring the smooth operation of the methanol main engine 5, while collecting residual methanol in the system to ensure safe system operation.

[0037] Another aspect of the present invention provides a method for supplying methanol fuel to a marine methanol fuel supply system according to any of the above-mentioned technical solutions, comprising: under the drive of hydraulic oil, a hydraulic submersible pump 2 placed in the tank body of a methanol storage tank 1 adjusts the methanol supply pressure to 13 bar, and transfers the methanol to a first heat exchanger 301 in a heat exchange unit 3 for heat exchange, wherein the temperature of the methanol after heat exchange in the first heat exchanger 301 is any value within the range of 25-50°C. The method further includes a step of stabilizing the methanol supply pressure: when the methanol supply pressure is too high, the hydraulic oil flow rate is reduced by a variable frequency motor, and the impeller speed in the pump body is reduced, thereby reducing the methanol supply pressure; when the methanol supply pressure is too low, the hydraulic oil flow rate is increased by a variable frequency motor, and the impeller speed in the pump body is increased, thereby increasing the methanol supply pressure; and / or when the methanol supply pressure is too high, the opening of the regulating valve 9 is increased, resulting in more methanol flowing back, thereby reducing the methanol supply pressure; when the methanol supply pressure is too low, the opening of the regulating valve 9 is decreased, resulting in less methanol flowing back, thereby increasing the methanol supply pressure.

[0038] The specific working process of the above-mentioned marine methanol supply system is as follows: Methanol in methanol storage tank 1 is pumped to heat exchange unit 3 via hydraulic submersible pump 2 and valve. Part of the methanol in heat exchange unit 3 flows back to methanol storage tank 1 via regulating valve 9. The methanol pressure is kept stable and meets the requirements of main engine 5 through dual regulation by the frequency converter of hydraulic submersible pump 2 and regulating valve 9. The methanol in heat exchange unit 3 is cooled by heat exchanger and filtered by dual filter to meet the temperature and precision requirements of main engine 5. It then passes through valve to fuel valve group 4 and finally reaches main engine 5. Methanol flowing back from main engine 5 is directly returned to methanol storage tank 1, and fuel oil flowing back from main engine 5 is returned to oil venting tank 7 via fuel valve group 4.

[0039] 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 are 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.

[0040] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. 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 this invention patent should be determined by the appended claims.

Claims

1. A method for supplying methanol fuel to a marine fuel supply system, characterized in that, The marine methanol fuel supply system includes: A methanol storage tank, wherein an oil suction well is provided at the bottom of the tank body, and the bottom of the methanol storage tank body is provided with a certain slope and the oil flows towards the oil suction well; A hydraulic submersible pump, wherein the pump body of the hydraulic submersible pump is located inside the methanol storage tank and installed at the oil suction well, and is driven by hydraulic oil; A heat exchange unit, using a mixture of water and ethylene glycol as the circulating heat exchange medium, includes a first heat exchanger and a second heat exchanger. In the first heat exchanger, a portion of the heat from the water and ethylene glycol mixture is transferred to methanol transported to the heat exchange unit by the hydraulic submersible pump. In the second heat exchanger, a portion of the heat from the hot fluid is transferred to the water and ethylene glycol mixture that has undergone heat exchange in the first heat exchanger. The temperature of the water and ethylene glycol mixture after heat exchange in the second heat exchanger is 5-15°C higher than the temperature of the water and ethylene glycol mixture after heat exchange in the first heat exchanger. The supply method includes: Driven by hydraulic oil, the hydraulic submersible pump located inside the methanol storage tank adjusts the methanol supply pressure to 13 bar and transfers the methanol to the first heat exchanger in the heat exchange unit for heat exchange. The temperature of the methanol after heat exchange by the first heat exchanger is any value between 25-50°C.

2. The supply method according to claim 1, characterized in that, The hydraulic submersible pump is connected to the hydraulic pump station on board via hydraulic oil pipes; the hydraulic submersible pump transports methanol from the methanol storage tank to the first heat exchanger in the heat exchange unit for heat exchange via a delivery pipeline, and returns the methanol that has been heat-exchanged by the heat exchange unit to the methanol storage tank via a return pipeline; the return pipeline is equipped with a regulating valve.

3. The supply method according to claim 1, characterized in that, It also includes a variable frequency motor connected to the hydraulic submersible pump.

4. The supply method according to claim 1, characterized in that, The heat exchange unit also includes a water-glycol pump that pressurizes the mixture of water and ethylene glycol, and a filter connected to the methanol outlet of the first heat exchanger, the filter comprising two filters connected in parallel.

5. The supply method according to claim 1, characterized in that, The heat fluid in the second heat exchanger is low-temperature fresh water from the ship.

6. The supply method according to claim 4, characterized in that, It also includes a fuel valve assembly connecting the heat exchange unit and the main unit, the fuel valve assembly being connected to the methanol outlet of the first heat exchanger via the filter.

7. The supply method according to claim 6, characterized in that, It also includes a methanol release chamber and an oil release chamber; the methanol release chamber is connected to the methanol storage tank, the heat exchange unit, and the fuel valve group via pipelines; the oil release chamber is connected to the fuel valve group via pipelines.

8. The supply method according to claim 7, characterized in that, It also includes a first nitrogen buffer tank and a second nitrogen buffer tank; the first nitrogen buffer tank is connected to the methanol storage tank, the methanol venting chamber and the oil venting chamber via pipelines; the second nitrogen buffer tank is connected to the heat exchange unit, the fuel valve group and the main unit via pipelines.

9. The supply method according to claim 1, characterized in that, This also includes steps to stabilize methanol supply pressure: When the methanol supply pressure is too high, the hydraulic oil flow rate is reduced by the variable frequency motor, and the impeller speed in the pump body is reduced, thereby lowering the methanol supply pressure; when the methanol supply pressure is too low, the hydraulic oil flow rate is increased by the variable frequency motor, and the impeller speed in the pump body is increased, thereby increasing the methanol supply pressure; and / or When the methanol supply pressure is too high, the opening of the regulating valve is increased, resulting in more methanol flowing back, thereby reducing the methanol supply pressure; when the methanol supply pressure is too low, the opening of the regulating valve is decreased, resulting in less methanol flowing back, thereby increasing the methanol supply pressure.

Images