Water / ethylene glycol heating-cooling system and method for LNG (Liquefied Natural Gas) system of ro-ro passenger ship

Abstract

The invention provides a water / ethylene glycol heating-cooling system and method for an LNG (Liquefied Natural Gas) system of a ro-ro passenger ship, and the ro-ro passenger ship is an LNG-diesel oil dual-fuel system and comprises a fuel treatment chamber and an LNG storage cabin; the water / ethylene glycol heating-cooling system comprises a cooling system and a heating system; the cooling system comprises a low-temperature water cooling system and a low-pressure water / ethylene glycol module; wherein the low-temperature water cooling system is connected with the low-pressure water / ethylene glycol module; the heating system comprises a high-pressure water / ethylene glycol module, a main engine cylinder sleeve water unit and a steam generator; the low-pressure water / ethylene glycol module is connected with a boil-off gas compressor unit, a BOG heater and a cooler of the fuel processing chamber, and the high-pressure water / ethylene glycol module is connected with an LNG evaporator of the fuel processing chamber. The heating system and the cooling system are additionally arranged in the LNG system, so that the LNG storage cabin can store liquid LNG, and the LNG can be directly used by the main engine and the auxiliary engine.

Description

Technical Field

[0001] The invention belongs to the technical field of ship construction, and relates to a water / ethylene glycol heating-cooling system and method of a ro-ro passenger ship LNG system. Background Art

[0002] Existing water glycol heating and cooling system for ro-ro passenger ships.

[0003] Ro-ro passenger ships are transport vessels that use their own power to transport cargo in and out of cargo holds and can carry passengers at the same time. They are mostly used for inland river ferries and medium- and short-distance shipping. At present, in order to comply with the development of environmental protection strategies, most Ro-ro passenger ships use dual-fuel engines. The dual-fuel main and auxiliary engines mainly include gas systems and fuel systems. The main fuel of the gas system is LNG (Liquefied-Natural-Gas, i.e. liquefied natural gas). LNG fuel is one of the clean energy sources currently advocated by the ship market and can meet the environmental protection needs of Ro-ro passenger ships; the main fuel of the fuel system is MGO (Marine-Gas-Oil, i.e. light diesel oil). As a mature fuel, MGO fuel has stable performance and can meet the high speed and flexibility requirements of Ro-ro passenger ships.

[0004] However, since LNG condenses into liquid at -162℃, the internal temperature of the LNG storage tank is about -170℃. Therefore, in order to keep the LNG in liquid state during storage, the LNG storage tank needs to be at a lower temperature. As a result, the temperature of LNG coming out of the LNG storage tank is very low and cannot be directly used by the main engine and auxiliary engine of the ro-pax ship. The LNG needs to be gradually heated up to meet the use requirements. Summary of the invention

[0005] The present invention provides a water / ethylene glycol heating-cooling system and method for a ro-ro passenger ship LNG system, which adopts a method of adding a heating system and a cooling system in the LNG system so that the LNG coming out of the LNG storage tank is gradually heated up to meet the use requirements, so that it can be directly used by the main engine and auxiliary engines, and the LNG storage tank can meet the liquid LNG storage requirements.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions.

[0007] In a first aspect, the present invention provides a water / glycol heating-cooling system for a ro-ro passenger ship LNG system, wherein the ro-ro passenger ship is an LNG-diesel dual-fuel system, the LNG-diesel dual-fuel system comprises a fuel processing chamber and an LNG storage tank, the fuel processing chamber comprises an LNG evaporator, and a boil-off gas compressor unit, a BOG heater and a cooler connected in sequence; the water / glycol heating-cooling system comprises a water / glycol unit, a cooling system and a heating system; wherein,

[0008] The cooling system includes a low-temperature water cooling system and a low-pressure water / ethylene glycol module; wherein the low-temperature water cooling system is connected to the low-pressure water / ethylene glycol module through a low-temperature water pipeline; the low-pressure water / ethylene glycol module includes a pressure controller and a first heat exchanger for pressure control and temperature reduction of the water / ethylene glycol solution;

[0009] The heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder jacket water unit and a steam generator; the high-pressure water / ethylene glycol module includes a pressure controller, a second heat exchanger and a third heat exchanger;

[0010] The low-pressure water / ethylene glycol module of the cooling system is connected to the boil-off gas compressor unit, BOG heater and cooler of the fuel processing chamber to cool the LNG storage tank;

[0011] The high-pressure water / ethylene glycol module of the heating system is connected to the LNG evaporator of the fuel processing chamber to heat the LNG from the LNG storage tank.

[0012] As an optional embodiment, the water / ethylene glycol unit includes a water storage tank, an ethylene glycol storage tank and a water / ethylene glycol solution storage tank.

[0013] As an optional implementation, the low-temperature water cooling system is connected to the first heat exchanger of the low-pressure water / ethylene glycol module via a low-temperature water pipeline, so as to provide a low-temperature heat exchange medium to the first heat exchanger.

[0014] As an optional implementation, in the low-temperature water cooling system, the temperature of the low-temperature water is 34-38°C.

[0015] In the present invention, the low-temperature water is cooled by seawater to achieve low temperature.

[0016] As an optional embodiment, the water / ethylene glycol storage tank is connected to the first heat exchanger via a water / ethylene glycol pipeline, so as to allow the water / ethylene glycol solution (or ethylene glycol aqueous solution) to exchange heat in the first heat exchanger, thereby reducing the temperature of the water / ethylene glycol solution.

[0017] As an optional embodiment, a water / ethylene glycol pipeline connected to the outlet of the first heat exchanger is connected to the fuel processing chamber for cooling the LNG by means of a cold water / ethylene glycol solution.

[0018] As an optional implementation, the evaporation gas compressor unit includes at least one evaporation gas compressor.

[0019] In the present invention, in the fuel processing chamber, the LNG gas in the LNG tank is continuously transported out and cooled in batches through the boil-off gas compressor unit, the BOG heater and the cooler, thereby achieving cooling of the LNG in the LNG storage tank.

[0020] As an optional implementation, the water / ethylene glycol pipeline is sequentially connected to the second heat exchanger and the third heat exchanger of the high-pressure water / ethylene glycol module, so as to allow the water / ethylene glycol solution to flow through the second heat exchanger for the first and second heating.

[0021] As an optional implementation, the main engine cylinder jacket water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module to perform a first temperature increase on the water / ethylene glycol solution flowing through the second heat exchanger.

[0022] As an optional implementation, the steam generator is connected to the third heat exchanger of the high-pressure water / ethylene glycol module via a steam pipeline, so as to heat the water / ethylene glycol solution flowing through the third heat exchanger for a second time.

[0023] As an optional embodiment, the third heat exchanger of the high-pressure water / ethylene glycol module is connected to the fuel processing chamber via a water / ethylene glycol pipeline, and is used to heat the LNG from the LNG storage tank with a heated water / ethylene glycol solution.

[0024] As an optional embodiment, the third heat exchanger of the high-pressure water / ethylene glycol module is connected to the LNG evaporator of the fuel processing chamber through a water / ethylene glycol pipeline, and is used to heat the LNG evaporator with the heated water / ethylene glycol solution, thereby heating the LNG from the LNG storage tank.

[0025] As an optional implementation, the cooling system further includes a plurality of pumps.

[0026] As an optional embodiment, the water storage tank is connected to the water / ethylene glycol storage tank via a pump, so as to pump water to the water / ethylene glycol storage tank to be mixed with ethylene glycol and stored.

[0027] As an optional implementation, the ethylene glycol storage tank is connected to the water / ethylene glycol storage tank via a pump, so as to pump ethylene glycol into the water / ethylene glycol storage tank to mix with water and store the mixture.

[0028] In the present invention, using LNG as fuel for ships can reduce operating costs and environmental pollution. Liquefied natural gas (LNG) condenses into liquid at -162°C. The internal temperature of the LNG storage tank is about -170°C, so the temperature of the LNG tank needs to be lowered.

[0029] In a second aspect, the present invention provides a water / ethylene glycol heating-cooling method for a ro-ro passenger ship LNG system, using the water / ethylene glycol heating-cooling system for the ro-ro passenger ship LNG system, the heating-cooling method comprises the following steps:

[0030] 1) Cooling of LNG:

[0031] The water-ethylene glycol solution enters the low-pressure water / ethylene glycol module for pressure control to obtain a low-pressure water / ethylene glycol solution, and then the low-pressure water / ethylene glycol solution flows through the first heat exchanger to exchange energy with cooling water from the low-temperature water cooling system to cool the water-ethylene glycol solution;

[0032] The cooled water-ethylene glycol solution enters the fuel processing chamber, flows through the boil-off gas compressor unit and the BOG heater and cooler, and absorbs the heat of the boil-off gas compressor unit and the BOG heater and cooler, thereby cooling the LNG in the LNG storage tank.

[0033] 2) Heating the LNG:

[0034] The water-ethylene glycol solution enters the high-pressure water / ethylene glycol module for pressure control to obtain a high-pressure water / ethylene glycol solution, and then the high-pressure water / ethylene glycol solution flows through the second heat exchanger to exchange heat with the main engine cylinder jacket water from the main engine cylinder jacket to achieve the first temperature increase of the water-ethylene glycol solution;

[0035] The water-ethylene glycol solution after the first heating flows through the third heat exchanger and undergoes secondary heat exchange through steam to achieve the second heating of the water-ethylene glycol solution;

[0036] The water glycol solution after the second heating enters the fuel processing chamber to heat the LNG evaporator to achieve the heating of the LNG.

[0037] In the present invention, in step 1), the water-ethylene glycol solution flows through the boil-off gas compressor unit and the BOG heater and cooler of the fuel processing chamber in sequence, and the water-ethylene glycol solution absorbs the heat of the boil-off gas compressor unit and the BOG heater and cooler to achieve cooling of the LNG in the LNG storage tank;

[0038] In the present invention, the temperature of the water-ethylene glycol solution after the second heating has reached the use requirement, and the water-ethylene glycol solution at this temperature can be used to heat the LNG evaporator.

[0039] In the present invention, the above technical features can be freely combined to form a new technical solution without conflicting with each other.

[0040] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0041] The water / ethylene glycol heating-cooling system of the LNG system of the ro-ro passenger ship provided by the present invention adopts the method of adding a heating system and a cooling system in the LNG system so that the LNG coming out of the LNG storage tank is gradually heated up to meet the use requirements, so that it can be directly used by the main engine and the auxiliary engine. In addition, the heating-cooling system can make the LNG storage tank meet the storage requirements of liquid LNG. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram showing a cooling process of a water / ethylene glycol heating-cooling system in Example 1 of the present invention;

[0043] Figure 2 A schematic diagram showing the heating process of the water / ethylene glycol heating-cooling system in Example 1 of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0046] Example 1

[0047] A water / ethylene glycol heating-cooling system for a ro-ro passenger ship LNG system, wherein the ro-ro passenger ship is an LNG-diesel dual-fuel system, the LNG-diesel dual-fuel system comprises a fuel processing room and an LNG storage tank, and the water / ethylene glycol heating-cooling system comprises a water / ethylene glycol unit, a cooling system and a heating system; wherein the fuel processing room comprises two boil-off gas compressor units, a BOG heater and cooler and an LNG evaporator; and the water / ethylene glycol unit comprises a water storage tank, an ethylene glycol storage tank and a water / ethylene glycol solution storage tank.

[0048] In this embodiment, in order to reduce operating costs and environmental pollution, the ro-ro passenger ship uses LNG as the fuel of the ship. Liquefied natural gas (LNG) condenses into liquid at -162°C, so the internal temperature of the LNG storage tank is about -170°C. In order to better keep the LNG in the LNG storage tank in liquid state, a cooling system is used to cool the LNG storage tank.

[0049] like Figure 1As shown, the cooling system includes a low-temperature water cooling system and a low-pressure water / ethylene glycol module. The low-pressure water / ethylene glycol module includes a pressure controller and a first heat exchanger for pressure control and cooling of the water / ethylene glycol solution. The low-temperature water cooling system is connected to the first heat exchanger of the low-pressure water / ethylene glycol module through a low-temperature water pipeline, and is used to provide a low-temperature heat exchange medium for the first heat exchanger of the low-pressure water / ethylene glycol module. The water / ethylene glycol storage tank is connected to the first heat exchanger through the water / ethylene glycol pipeline, and is used to cool the water / ethylene glycol solution through the first heat exchanger.

[0050] The water / ethylene glycol pipeline connected to the outlet of the first heat exchanger is connected to the fuel processing chamber, and is used to cool the LNG through the cooled water / ethylene glycol solution. Specifically, in the fuel processing chamber, two evaporation gas compressor units and the BOG heater and cooler are connected in sequence; the cooled water / ethylene glycol solution flows through the two evaporation gas compressor units and the BOG heater and cooler in sequence, absorbing the heat of the above devices, thereby cooling the LNG.

[0051] Since the temperature of LNG coming out of the LNG storage tank is very low and cannot be directly used by the main engine and auxiliary engines of the passenger and vehicle ferry, a heating system is used to gradually heat up the LNG.

[0052] like Figure 2 As shown, the heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder jacket water unit and a steam generator. Among them, the high-pressure water / ethylene glycol module includes a pressure controller, a second heat exchanger and a third heat exchanger.

[0053] The water / ethylene glycol storage tank is connected to the second heat exchanger and the third heat exchanger of the high-pressure water / ethylene glycol module in sequence through the water / ethylene glycol pipeline, so as to make the water / ethylene glycol solution flow through the second heat exchanger for the first and second heating.

[0054] Specifically, the main engine cylinder water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module to heat the water / ethylene glycol solution flowing through the second heat exchanger for the first time. The steam generator is connected to the third heat exchanger of the high-pressure water / ethylene glycol module through a steam pipeline to heat the water / ethylene glycol solution flowing through the third heat exchanger for the second time.

[0055] The third heat exchanger of the high-pressure water / ethylene glycol module is connected to the LNG evaporator of the fuel processing chamber through a water / ethylene glycol pipeline, and is used to heat the LNG evaporator of the fuel processing chamber with the heated water / ethylene glycol solution, thereby using the heated LNG evaporator to heat the LNG from the LNG storage tank.

[0056] Example 2

[0057] A water / ethylene glycol heating-cooling method for a ro-ro passenger ship LNG system, using the water / ethylene glycol heating-cooling system for the ro-ro passenger ship LNG system in Example 1, the heating-cooling method comprising the following steps:

[0058] S1. Cooling LNG:

[0059] The water-glycol solution enters the low-pressure water / glycol module for pressure control, then flows through the first heat exchanger to exchange energy with the cooling water from the low-temperature water cooling system to cool the water-glycol solution;

[0060] The cooled water-glycol solution enters the fuel processing chamber, flows through the boil-off gas compressor unit and the BOG heater and cooler, and absorbs the heat of the boil-off gas compressor unit and the BOG heater and cooler, thereby cooling the LNG in the LNG storage tank.

[0061] S2. Heating the LNG:

[0062] The water-glycol solution enters the high-pressure water / glycol module for pressure control, then flows through the second heat exchanger to exchange heat with the main engine jacket water from the main engine jacket, thereby achieving the first temperature rise of the water-glycol solution;

[0063] The water-ethylene glycol solution after the first heating flows through the third heat exchanger and undergoes secondary heat exchange through steam to achieve the second heating of the water-ethylene glycol solution;

[0064] The water glycol solution after the second heating enters the fuel processing chamber to heat the LNG evaporator, thereby achieving the heating of the LNG.

[0065] In this embodiment, in step S1, the water-ethylene glycol solution is passed through the boil-off gas compressor unit and the BOG heater and cooler of the fuel processing chamber in sequence, and the water-ethylene glycol solution absorbs the heat of the boil-off gas compressor unit and the BOG heater and cooler to achieve cooling of the LNG in the LNG storage tank;

[0066] In step S2, the temperature of the water glycol solution after the second heating has reached the use requirements, and the water glycol solution at this temperature can be used to heat the LNG evaporator so that the LNG coming out of the LNG storage tank is gradually heated to meet the use requirements of the main engine and auxiliary engines of the passenger and vehicle ferry.

[0067] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A water / ethylene glycol heating-cooling system for a ro-ro passenger ship LNG system, characterized in that: The ro-ro passenger ship is an LNG-diesel dual-fuel system, which includes a fuel processing room and an LNG storage tank. The fuel processing room includes an LNG evaporator, and a BOG compressor unit, a BOG heater and a cooler connected in sequence; the water / ethylene glycol heating-cooling system includes a water / ethylene glycol unit, a cooling system and a heating system; the water / ethylene glycol unit includes a water storage tank, an ethylene glycol storage tank and a water / ethylene glycol solution storage tank; wherein, The cooling system includes a low-temperature water cooling system and a low-pressure water / ethylene glycol module; wherein the low-temperature water cooling system is connected to the low-pressure water / ethylene glycol module through a low-temperature water pipeline; the low-pressure water / ethylene glycol module includes a pressure controller and a first heat exchanger for pressure control and temperature reduction of the water / ethylene glycol solution; The heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder jacket water unit and a steam generator; the high-pressure water / ethylene glycol module includes a pressure controller, a second heat exchanger and a third heat exchanger; The low-pressure water / ethylene glycol module of the cooling system is connected to the boil-off gas compressor unit, BOG heater and cooler of the fuel processing chamber to cool the LNG storage tank; The high-pressure water / ethylene glycol module of the heating system is connected to the LNG evaporator of the fuel processing chamber to heat the LNG from the LNG storage tank.

2. The water / glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 1, characterized in that: The low-temperature water cooling system is connected to the first heat exchanger of the low-pressure water / ethylene glycol module through a low-temperature water pipeline, and is used to provide a low-temperature heat exchange medium to the first heat exchanger.

3. The water / glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 2, characterized in that: In the low-temperature water cooling system, the temperature of the low-temperature water is 34-38°C.

4. The water / ethylene glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to any one of claims 1 to 3, characterized in that: The water / ethylene glycol storage tank is connected to the first heat exchanger via a water / ethylene glycol pipeline, and is used to allow the water / ethylene glycol solution to exchange heat in the first heat exchanger, thereby reducing the temperature of the water / ethylene glycol solution; The water / ethylene glycol pipeline connected to the outlet of the first heat exchanger is connected to the fuel processing chamber for cooling the LNG by means of a cold water / ethylene glycol solution.

5. The water / ethylene glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 1, characterized in that: The boil-off gas compressor unit includes at least one boil-off gas compressor.

6. The water / glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 1, characterized in that: The water / ethylene glycol pipeline is connected to the second heat exchanger and the third heat exchanger of the high-pressure water / ethylene glycol module in sequence, so as to allow the water / ethylene glycol solution to flow through the second heat exchanger for a first heating and a second heating; The main engine cylinder jacket water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module, and is used to heat the water / ethylene glycol solution flowing through the second heat exchanger for the first time; The steam generator is connected to the third heat exchanger of the high-pressure water / ethylene glycol module through a steam pipeline, and is used to heat the water / ethylene glycol solution flowing through the third heat exchanger for a second time.

7. The water / glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 6, characterized in that: The third heat exchanger of the high-pressure water / ethylene glycol module is connected to the fuel processing chamber through a water / ethylene glycol pipeline, and is used to heat the LNG from the LNG storage tank using the heated water / ethylene glycol solution.

8. The water / glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 7, characterized in that: The third heat exchanger of the high-pressure water / ethylene glycol module is connected to the LNG evaporator of the fuel processing chamber through a water / ethylene glycol pipeline, and is used to heat the LNG evaporator with the heated water / ethylene glycol solution, thereby heating the LNG from the LNG storage tank.

9. The water / ethylene glycol heating-cooling system of the LNG system of a ro-ro passenger ship according to claim 1, characterized in that: The cooling system also includes a plurality of pumps.

10. A water / ethylene glycol heating-cooling method for a ro-ro passenger ship LNG system, characterized in that: The heating-cooling method adopts the water / ethylene glycol heating-cooling system of the ro-ro passenger ship LNG system according to any one of claims 1-9, and the heating-cooling method comprises the following steps: 1) Cooling of LNG: The water-ethylene glycol solution enters the low-pressure water / ethylene glycol module for pressure control to obtain a low-pressure water / ethylene glycol solution, and then the low-pressure water / ethylene glycol solution flows through the first heat exchanger to exchange energy with cooling water from the low-temperature water cooling system to cool the water-ethylene glycol solution; The cooled water-glycol solution enters the fuel processing chamber, flows through the boil-off gas compressor unit and the BOG heater and cooler, and absorbs the heat of the boil-off gas compressor unit and the BOG heater and cooler, thereby cooling the LNG in the LNG storage tank. 2) Heating LNG: The water-ethylene glycol solution enters the high-pressure water / ethylene glycol module for pressure control to obtain a high-pressure water / ethylene glycol solution, and then the high-pressure water / ethylene glycol solution flows through the second heat exchanger to exchange heat with the main engine cylinder jacket water from the main engine cylinder jacket to achieve the first temperature increase of the water-ethylene glycol solution; The water-ethylene glycol solution after the first heating flows through the third heat exchanger and undergoes secondary heat exchange through steam to achieve the second heating of the water-ethylene glycol solution; The water glycol solution after the second heating enters the fuel processing chamber to heat the LNG evaporator to achieve the heating of the LNG.

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