Sealing oil system for methanol fuel of marine low-speed diesel engine

Abstract

A sealing oil system for methanol fuel of a marine low-speed diesel engine comprises a sealing oil tank which is connected with and conveys high-pressure sealing oil to a methanol injector through a sealing oil way and seals the methanol fuel in the methanol injector; the pressure pump is used for pumping out the sealing oil from the sealing oil cabinet, pressurizing and heating the sealing oil to be above the boiling point of methanol, evaporating methanol fuel mixed in the sealing oil into steam, discharging the steam, and then sending the steam back to the sealing oil cabinet; the exhaust pipeline is used for exhausting methanol steam in the sealed oil tank; the hydrocarbon sensor is mounted on the exhaust pipeline and is used for monitoring the concentration of the methanol gas and realizing alarming and operation mode switching when the concentration exceeds the standard. According to the invention, the sealing of the methanol fuel for the ship, the removal and separation of methanol mixed in the sealing oil and the monitoring and alarming of the methanol gas concentration are realized, and the normal operation of the low-speed methanol diesel engine for the ship and the safety of the ship and personnel are ensured.

Description

Technical Field

[0001] The invention relates to a fuel system of a low-speed marine diesel engine, in particular to a sealing oil system of methanol fuel for a low-speed marine diesel engine, belonging to the technical field of marine diesel engines. Background Art

[0002] Under the current situation where the development of clean energy and the reduction of carbon emissions have become the goals of the industry, methanol has gradually changed from a chemical raw material to a clean energy fuel. In the field of marine low-speed diesel engines, methanol has gradually replaced diesel as a clean fuel for marine low-speed engines. Methanol has the advantages of being economical, environmentally friendly, and having high combustion efficiency, but at the same time, methanol is easy to volatilize and methanol gas is toxic, which can cause harm to personnel and cause ship fires; and methanol gas is colorless and smells like alcohol, which can easily lead to misjudgment, so it is necessary to seal the methanol gas, strengthen exhaust ventilation, and take safety monitoring measures during the use of methanol fuel.

[0003] In view of the volatile, flammable and toxic characteristics of methanol fuel and the small space and poor ventilation of the ship hull, a safety system for sealing and monitoring methanol fuel and methanol gas must be established on the ship's low-speed methanol diesel engine to ensure the safety of the ship and its crew. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a sealing oil system for methanol fuel of a marine low-speed diesel engine, in view of the fact that methanol fuel is volatile and toxic and poses a potential safety hazard. The sealing oil is used to seal the methanol fuel and remove the methanol leaked into the sealing oil. At the same time, the methanol gas is exhausted and monitored to ensure the safety of the ship and the ship's crew.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0006] A sealing oil system for methanol fuel of a low-speed marine diesel engine, the low-speed marine diesel engine comprising a control system, a methanol injector and a ship ventilation system; the sealing oil system comprises:

[0007] A sealing oil tank, used for storing sealing oil, connected to and conveying high-pressure sealing oil to the methanol injector through a sealing oil line, so as to seal the methanol fuel in a non-injection state in the methanol injector;

[0008] A pressure pump is connected to the sealing oil tank through a pressurized and heated pipeline, extracts the sealing oil from the sealing oil tank, pressurizes and heats it to above the boiling point of methanol, evaporates the methanol fuel mixed in the sealing oil into methanol vapor and discharges it, and then returns the sealing oil to the sealing oil tank;

[0009] An exhaust pipeline connects the upper part of the sealed oil tank with the ship ventilation system, and is used to discharge the methanol vapor in the sealed oil tank and enter the ship ventilation system for dilution before being discharged to the outside.

[0010] As a further improvement, a hydrocarbon sensor is installed in the exhaust pipeline to monitor the methanol gas concentration in the exhaust pipeline. When the methanol gas concentration exceeds the standard, an alarm signal is sent to the control system, and the control system switches the operating mode of the marine low-speed diesel engine from methanol mode to diesel mode.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1. The pressure difference between high-pressure sealing oil and low-pressure methanol fuel is used to seal the methanol fuel in the methanol injector, reducing the safety hazards caused by volatile, flammable and toxic methanol fuel to ships and personnel.

[0013] 2. For methanol fuel mixed in the sealing oil, the sealing oil temperature is raised to above the ignition point of methanol, so that the methanol evaporates and separates from the sealing oil, and then exhaust ventilation treatment is performed to remove the methanol gas, further reducing the safety risk.

[0014] 3. The sealing oil system is equipped with a hydrocarbon sensor to monitor the methanol gas concentration in the system. Once it exceeds the standard, a danger signal will be transmitted, and the diesel engine operation mode will be switched through the control system to ensure the safety of the ship and personnel.

[0015] In summary, the present invention realizes the sealing of methanol fuel for ships, the removal and separation of methanol mixed in the sealing oil, and the monitoring and alarm of methanol gas concentration, ensuring the normal operation of the ship's low-speed methanol diesel engine and the safety of the ship and personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a system principle diagram of the present invention.

[0017] In the figure,

[0018] 1—methanol injector, 2—sealed oil circuit, 3—sealed oil cabinet, 4—boosting pump, 5—pressurization and heating pipeline, 6—exhaust pipeline, 7—hydrocarbon sensor. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings in order to more clearly understand the structure and use of the present invention, but this is not intended to limit the scope of protection of the present invention.

[0020] The invention is used for sealing methanol fuel of a low-speed marine diesel engine. The marine diesel engine comprises a control system, a methanol injector and a marine ventilation system.

[0021] See also Figure 1 The sealing oil system includes a sealing oil tank 3, a booster pump 4, an exhaust pipeline 6 and a hydrocarbon sensor 7.

[0022] The sealing oil tank 3 is used to store sealing oil. The sealing oil is drawn out from the sealing oil tank 3 through the sealing oil circuit 2, pressurized into high-pressure sealing oil and sent to the methanol injector 1. This high-pressure sealing oil utilizes the pressure difference between the high-pressure sealing oil and the low-pressure methanol fuel to seal the methanol fuel in the non-injection state in the methanol injector 1 to prevent methanol leakage.

[0023] Since the sealing oil may come into contact with methanol, for example, when the methanol injector 1 injects methanol, the methanol pressure will be briefly higher than the sealing oil pressure, causing methanol fuel to mix into the sealing oil. A very small amount of methanol may enter the sealing oil tank 3 along the sealing oil line 2, so the sealing oil needs to be de-methanoled.

[0024] In order to remove the methanol flowing into the sealed oil tank 3, the sealed oil tank 3 is equipped with a pressurized temperature-raising pipeline 5, see Figure 1 The booster pump 4 is connected to the sealing oil tank 3 through the pressurizing and heating pipeline 5, and the sealing oil is extracted from the sealing oil tank 3, pressurized and heated to above the boiling point of methanol. Since methanol and sealing oil are immiscible and methanol has a low boiling point, after the sealing oil temperature is raised to above the ignition point of methanol, the methanol fuel mixed in the sealing oil will evaporate into methanol vapor, which promotes the separation of methanol vapor and sealing oil. The sealing oil after methanol separation is then sent back to the sealing oil tank 3. After returning to the sealing oil tank 3, the sealing oil is stored in the lower part of the sealing oil tank 3, and the methanol vapor is stored in the upper part of the sealing oil tank 3.

[0025] See also Figure 1 An exhaust pipe 6 is installed above the sealed oil tank 3 to perform exhaust ventilation treatment, remove methanol gas, and discharge methanol vapor from the upper part of the sealed oil tank 3 out of the sealed oil tank 3. The exhaust pipe 6 connects the upper part of the sealed oil tank 3 to the ship ventilation system, and the methanol vapor enters the ship ventilation system from the sealed oil tank 3 through the exhaust pipe 6 for dilution and then is discharged to the outside.

[0026] See also Figure 1 A hydrocarbon sensor 7 is installed on the exhaust pipeline 6 to monitor the methanol gas concentration in the exhaust pipeline 6; when the hydrocarbon sensor 7 finds that the methanol gas concentration exceeds the standard, an alarm signal is sent to the control system, and the control system switches the operating mode of the marine low-speed diesel engine from the methanol mode to the diesel mode to ensure the safety of the ship and personnel.

[0027] The specific working process of the present invention is as follows:

[0028] The high-pressure sealing oil in the sealing oil system performs a pressure differential seal on the low-pressure methanol fuel to prevent methanol leakage; however, during the sealing process, a small amount of methanol fuel may enter the sealing oil system and enter the sealing oil tank 3 along with the sealing oil. In order to prevent the methanol mixed in the sealing oil tank 3 from accumulating, another oil circuit circulation is performed in the sealing oil tank 3. In the circulation of this pressurized and heated pipeline 5, the sealing oil in the sealing oil tank 3 is pressurized and heated to above the boiling point of methanol. When the methanol is heated to the boiling point, an evaporation effect will occur, and it will be converted into methanol vapor and gathered in the upper cavity area of ​​the sealing oil tank 3; when the gas in the sealing oil tank 3 is exhausted, the methanol gas is discharged from the sealing oil tank 3 into the ship's ventilation system, and then diluted and discharged; the methanol gas concentration is monitored by the hydrocarbon sensor 7 in the exhaust pipeline 6, and the diesel engine operation mode is switched when the methanol gas concentration exceeds the standard.

[0029] In view of the characteristics of methanol fuel, the present invention establishes a methanol sealing oil system for ensuring safety on a low-speed methanol diesel engine, effectively seals the methanol fuel, and at the same time, if the methanol gas exceeds the standard, the operation mode of the low-speed methanol diesel engine will be switched, the diesel mode will be started, and the methanol mode will be suspended to achieve the purpose of ensuring safety. In short, the sealing oil system of methanol fuel for a marine low-speed diesel engine can not only achieve the sealing of methanol fuel, but also remove the methanol mixed in the sealing oil, and at the same time, the monitoring of methanol gas is also achieved, and the safety of the ship and the staff is finally ensured.

[0030] The above are only preferred embodiments of the present invention. It must be pointed out that all equivalent modifications, changes and amendments made by technicians in the relevant field according to the application content of the present invention should fall within the protection scope of the present invention.

Claims

1. A sealing oil system for methanol fuel of a marine low-speed diesel engine, the marine low-speed diesel engine comprising a control system, a methanol injector and a ship ventilation system; characterized in that: The sealing oil system comprises: A sealing oil tank, used for storing sealing oil, connected to and conveying high-pressure sealing oil to the methanol injector through a sealing oil line, so as to seal the methanol fuel in a non-injection state in the methanol injector; A pressure pump is connected to the sealing oil tank through a pressurized and heated pipeline, extracts the sealing oil from the sealing oil tank, pressurizes and heats it to above the boiling point of methanol, evaporates the methanol fuel mixed in the sealing oil into methanol vapor and discharges it, and then returns the sealing oil to the sealing oil tank; An exhaust pipeline connects the upper part of the sealed oil tank with the ship ventilation system, and is used to discharge the methanol vapor in the sealed oil tank and enter the ship ventilation system for dilution before being discharged to the outside.

2. The sealing oil system for methanol fuel of a marine low-speed diesel engine according to claim 1, characterized in that: A hydrocarbon sensor is installed on the exhaust pipeline to monitor the methanol gas concentration in the exhaust pipeline. When the methanol gas concentration exceeds the standard, an alarm signal is sent to the control system, and the control system switches the operating mode of the marine low-speed diesel engine from the methanol mode to the diesel mode.

Images