Water / glycol heating-cooling system and method for a passenger and roll-on ship LNG system

Abstract

The application provides a water / glycol heating-cooling system and method of a passenger-rolling ship LNG system, the passenger-rolling ship is a LNG-diesel dual fuel system, comprising a fuel processing chamber and an LNG storage cabin; the water / 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 / glycol module; wherein the low-temperature water cooling system is connected with the low-pressure water / glycol module; the heating system comprises a high-pressure water / glycol module, a main engine cylinder jacket water unit and a steam generator; the low-pressure water / glycol module is connected with an evaporation gas compressor unit, a BOG heater and a cooler of the fuel processing chamber, and the high-pressure water / glycol module is connected with an LNG evaporator of the fuel processing chamber. The heating system and the cooling system are added 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

[0001] This application claims priority to Chinese Patent Application No. 202411483514.7, filed on October 23, 2024, entitled "Water / Ethylene Glycol Heating-Cooling System and Method for LNG System of Ro-Ro Ship", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of shipbuilding technology and relates to a water / ethylene glycol heating-cooling system and method for a passenger roll-on / roll-off ship LNG system. Background Technology

[0003] The existing ro-ro passenger ship uses a water glycol heating and cooling system.

[0004] Ro-Ro passenger ships are self-propelled vessels that can simultaneously transport passengers and move cargo in and out of their hold. They are primarily used for inland waterway ferries and short- to medium-distance maritime transport. Currently, in order to comply with environmental protection strategies, most Ro-Ro passenger ships adopt dual-fuel engines. The dual-fuel main and auxiliary engines mainly include a gas system and an oil system. The main fuel for the gas system is LNG (Liquefied Natural Gas), which is one of the clean energy sources currently favored in the shipping market and can meet the environmental protection requirements of Ro-Ro passenger ships. The main fuel for the oil system is MGO (Marine Gas Oil), which is a mature fuel with stable performance and can meet the high-speed and flexibility requirements of Ro-Ro passenger ships.

[0005] However, since LNG condenses into a liquid at -162°C, and the internal temperature of the LNG storage tank is approximately -170°C, the LNG storage tank needs to be even colder to keep the LNG in a liquid state during storage. Consequently, the LNG exiting the storage tank is at a very low temperature and cannot be directly used by the main and auxiliary engines of the passenger / roll-on / roll-off ship. The LNG needs to be gradually heated to meet usage requirements. Summary of the Invention

[0006] This invention provides a water / ethylene glycol heating-cooling system and method for a LNG system in a passenger roll-on / roll-off ship. By adding a heating system and a cooling system to the LNG system, the LNG coming out of the LNG storage tank is gradually heated to meet the usage requirements, so that it can be directly used by the main engine and auxiliary engines, and the LNG storage tank can meet the requirements for liquid LNG storage.

[0007] To achieve the above objectives, the present invention adopts the following technical solution.

[0008] In a first aspect, the present invention provides a water / ethylene glycol heating-cooling system for a passenger ro-ro ship LNG system. The passenger ro-ro ship is an LNG-diesel dual-fuel system, which includes a fuel processing chamber and an LNG storage tank. The fuel processing chamber includes an LNG evaporator and, in sequence, an evaporative gas compressor unit, a BOG heater, and a cooler. The water / ethylene glycol heating-cooling system includes a water / ethylene glycol unit, a cooling system, and a heating system.

[0009] 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, used for pressure control and cooling of the water / ethylene glycol solution;

[0010] The heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder liner 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;

[0011] The low-pressure water / ethylene glycol module of the cooling system is connected to the evaporator compressor unit, BOG heater and cooler of the fuel processing chamber for cooling the LNG storage tank.

[0012] The high-pressure water / glycol module of the heating system is connected to the LNG evaporator in the fuel processing chamber for heating the LNG from the LNG storage tank.

[0013] As an optional implementation, the water / ethylene glycol unit includes a water storage tank, an ethylene glycol storage tank, and a water / ethylene glycol solution storage tank.

[0014] 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, and is used to provide a low-temperature heat exchange medium to the first heat exchanger.

[0015] As an optional implementation, in the low-temperature water cooling system, the temperature of the low-temperature water is 34~38℃.

[0016] In this invention, the low-temperature water is cooled by seawater to achieve the low temperature.

[0017] As an optional implementation, the water / ethylene glycol storage tank is connected to the first heat exchanger via a water / ethylene glycol pipeline, so that the water / ethylene glycol solution (or ethylene glycol aqueous solution) can exchange heat in the first heat exchanger, thereby reducing the temperature of the water / ethylene glycol solution.

[0018] As an optional implementation, a water / glycol pipeline connected to the outlet of the first heat exchanger is connected to the fuel processing chamber for cooling the LNG with a cold water / glycol solution.

[0019] As an optional implementation, the evaporator compressor unit includes at least one evaporator compressor.

[0020] In this invention, in the fuel processing chamber, the LNG gas in the LNG tank is continuously transported out and cooled in batches through the evaporative gas compressor unit, BOG heater and cooler, thereby achieving the cooling of LNG in the LNG storage tank.

[0021] 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 a first heating and a second heating.

[0022] As an optional implementation, the main engine cylinder liner water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module for the first heating of the water / ethylene glycol solution flowing through the second heat exchanger.

[0023] 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, for a second heating of the water / ethylene glycol solution flowing through the third heat exchanger.

[0024] As an optional implementation, 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 using a heated water / ethylene glycol solution.

[0025] As an optional implementation, the third heat exchanger of the high-pressure water / ethylene glycol module is connected to the LNG evaporator in the fuel processing chamber via a water / ethylene glycol pipeline, and is used to heat the LNG evaporator by contacting the heated water / ethylene glycol solution, thereby heating the LNG from the LNG storage tank.

[0026] As an optional implementation, the cooling system also includes multiple pumps.

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

[0028] As an optional implementation, the ethylene glycol storage tank is connected to the water / ethylene glycol storage tank via a pump, for pumping ethylene glycol into the water / ethylene glycol storage tank to mix with water and store it.

[0029] In this invention, using LNG as ship fuel can reduce operating costs and decrease environmental pollution. Liquefied natural gas (LNG) condenses into a liquid at -162°C. The internal temperature of an LNG storage tank is approximately -170°C, therefore the LNG tank needs to be cooled.

[0030] Secondly, the present invention provides a water / ethylene glycol heating-cooling method for a ro-ro LNG system, employing the aforementioned water / ethylene glycol heating-cooling system for a ro-ro LNG system, the heating-cooling method comprising the following steps:

[0031] 1) Cooling the LNG:

[0032] 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. Then, the low-pressure water / ethylene glycol solution flows through the first heat exchanger to exchange energy with the cooling water from the low-temperature water cooling system, thereby cooling the water-ethylene glycol solution.

[0033] The cooled water-ethylene glycol solution enters the fuel handling chamber and flows through the evaporative gas compressor unit and the BOG heater and cooler. The water-ethylene glycol solution absorbs the heat from the evaporative gas compressor unit and the BOG heater and cooler, thereby cooling the LNG in the LNG storage tank.

[0034] 2) Heating the LNG:

[0035] 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. Then, the high-pressure water / ethylene glycol solution flows through the second heat exchanger to exchange heat with the main engine cylinder liner water from the main engine cylinder liner, thereby achieving the first temperature rise of the water-ethylene glycol solution.

[0036] After the first heating, the water-ethylene glycol solution flows through the third heat exchanger and undergoes secondary heat exchange with steam, thus achieving a second heating of the water-ethylene glycol solution.

[0037] The water-glycol solution, after a second heating, enters the fuel processing chamber to heat the LNG evaporator, thus raising the temperature of the LNG.

[0038] In this invention, in step 1), the water-ethylene glycol solution flows sequentially through the evaporative gas compressor unit and the BOG heater and cooler in the fuel processing chamber, and absorbs the heat of the evaporative gas compressor unit and the BOG heater and cooler through the water-ethylene glycol solution, so as to cool down the LNG in the LNG storage tank.

[0039] In this invention, the temperature of the water-glycol solution after the second heating has reached the required level, and this temperature of water-glycol solution can be used to heat the LNG evaporator.

[0040] In this invention, the above-mentioned technical features can be freely combined to form new technical solutions, provided they do not conflict with each other.

[0041] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0042] The water / ethylene glycol heating-cooling system for LNG systems in passenger roll-on / roll-off ships provided by this invention employs a method of adding a heating system and a cooling system to the LNG system to gradually raise the temperature of the LNG coming out of the LNG storage tank to meet the usage requirements, so that it can be directly used by the main engine and auxiliary engines. In addition, this heating-cooling system enables the LNG storage tank to meet the storage requirements of liquid LNG. Attached Figure Description

[0043] Figure 1 This diagram illustrates the cooling process of the water / ethylene glycol heating-cooling system in Embodiment 1 of the present invention.

[0044] Figure 2 This diagram illustrates the heating process of the water / ethylene glycol heating-cooling system in Embodiment 1 of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0047] Example 1

[0048] 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 includes a fuel handling chamber and an LNG storage tank, and the water / ethylene glycol heating-cooling system includes a water / ethylene glycol unit, a cooling system and a heating system; wherein, the fuel handling chamber includes two evaporative gas compressor units, a BOG heater and cooler and an LNG evaporator; the water / ethylene glycol unit includes a water storage tank, an ethylene glycol storage tank and a water / ethylene glycol solution storage tank.

[0049] In this embodiment, to reduce operating costs and minimize environmental pollution, the ro-ro passenger ship uses LNG as its fuel. Liquefied natural gas (LNG) condenses into a liquid at -162°C, so the internal temperature of the LNG storage tank is approximately -170°C. To better maintain the LNG in a liquid state within the storage tank, a cooling system is used to lower the temperature of the LNG storage tank.

[0050] like Figure 1 As shown, the cooling system includes a cryogenic 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, used for pressure control and cooling of the water / ethylene glycol solution. The cryogenic water cooling system is connected to the first heat exchanger of the low-pressure water / ethylene glycol module via a cryogenic water pipeline, providing a cryogenic heat exchange medium to the first heat exchanger. The water / ethylene glycol storage tank is connected to the first heat exchanger via a water / ethylene glycol pipeline, allowing the water / ethylene glycol solution to pass through the first heat exchanger for cooling.

[0051] A water / glycol pipeline connected to the outlet of the first heat exchanger is connected to the fuel processing chamber for cooling the LNG using a cooled water / glycol solution. Specifically, in the fuel processing chamber, two evaporative gas compressor units and a BOG heater and cooler are connected in sequence; the cooled water / glycol solution flows sequentially through the two evaporative gas compressor units and the BOG heater and cooler, absorbing heat from these devices, thereby cooling the LNG.

[0052] Because the LNG coming out of the LNG storage tank is at a very low temperature, it cannot be directly used by the main and auxiliary engines of the passenger roll-on / roll-off ship. Therefore, a heating system is used to gradually raise the temperature of the LNG.

[0053] like Figure 2 As shown, the heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder liner 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.

[0054] The water / ethylene glycol storage tank is connected in sequence to the second and third heat exchangers of the high-pressure water / ethylene glycol module via water / ethylene glycol pipelines, so that the water / ethylene glycol solution can flow through the second heat exchanger for the first and second heating.

[0055] Specifically, the main engine cylinder liner water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module to provide the initial heating of the water / ethylene glycol solution flowing through the second heat exchanger. The steam generator is connected to the third heat exchanger of the high-pressure water / ethylene glycol module via a steam pipeline to provide the second heating of the water / ethylene glycol solution flowing through the third heat exchanger.

[0056] The third heat exchanger of the high-pressure water / ethylene glycol module is connected to the LNG evaporator in the fuel processing chamber via a water / ethylene glycol pipeline. It is used to heat the LNG evaporator in 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.

[0057] Example 2

[0058] A water / ethylene glycol heating-cooling method for a ro-ro LNG system, employing the water / ethylene glycol heating-cooling system of the ro-ro LNG system in Example 1, includes the following steps:

[0059] S1. Cooling the LNG:

[0060] The water-ethylene glycol solution enters the low-pressure water / ethylene glycol module for pressure control, and then flows through the first heat exchanger to exchange energy with the cooling water from the low-temperature water cooling system, thereby cooling the water-ethylene glycol solution.

[0061] After cooling, the water-ethylene glycol solution enters the fuel handling chamber and flows through the evaporative gas compressor unit and the BOG heater and cooler. The water-ethylene glycol solution absorbs the heat from the evaporative gas compressor unit and the BOG heater and cooler, thereby cooling the LNG in the LNG storage tank.

[0062] S2. Heating the LNG:

[0063] The water-ethylene glycol solution enters the high-pressure water / ethylene glycol module for pressure control, and then flows through the second heat exchanger to exchange heat with the main cylinder liner water from the main cylinder liner, thus achieving the first temperature rise of the water-ethylene glycol solution.

[0064] After the first heating, the water-ethylene glycol solution flows through the third heat exchanger and undergoes secondary heat exchange with steam, thus achieving a second heating of the water-ethylene glycol solution.

[0065] The water-glycol solution, after a second heating, enters the fuel processing chamber to heat the LNG evaporator, thus raising the temperature of the LNG.

[0066] In this embodiment, in step S1, the water-ethylene glycol solution flows sequentially through the evaporator compressor unit and the BOG heater and cooler in the fuel processing chamber. The water-ethylene glycol solution absorbs the heat from the evaporator compressor unit and the BOG heater and cooler to cool the LNG in the LNG storage tank.

[0067] In step S2, the temperature of the water-glycol solution after the second heating has reached the required level. This temperature of water-glycol solution can be used to heat the LNG evaporator so that the LNG coming out of the LNG storage tank can be gradually heated to meet the requirements of the main engine and auxiliary engines of the passenger roll-on / roll-off ship.

[0068] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A water / ethylene glycol heating-cooling system for an LNG system on a passenger roll-on / roll-off ship, characterized in that, The passenger ro-ro ship uses an LNG-diesel dual-fuel system. The LNG-diesel dual-fuel system includes a fuel handling chamber and an LNG storage tank. The fuel handling chamber includes an LNG evaporator and, in sequence, an evaporative gas compressor unit, a BOG heater, and a cooler. 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. The cooling system includes a cryogenic water cooling system and a low-pressure water / ethylene glycol module. The cryogenic water cooling system is connected to the low-pressure water / ethylene glycol module via a cryogenic water pipeline. 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 water / ethylene glycol storage tank is connected to the first heat exchanger via a water / ethylene glycol pipeline, allowing the water / ethylene glycol solution to exchange heat within the first heat exchanger, thereby lowering the temperature of the water / ethylene glycol solution. 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 using a cold water / ethylene glycol solution. The heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder liner 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 water / ethylene glycol pipeline is sequentially connected to the second and third heat exchangers of the high-pressure water / ethylene glycol module, allowing the water / ethylene glycol solution to undergo a first and second temperature increase as it flows through the second heat exchanger. The main engine cylinder liner water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module, providing a first temperature increase to the water / ethylene glycol solution flowing through it. The steam generator is connected to the third heat exchanger of the high-pressure water / ethylene glycol module via a steam pipeline, providing a second temperature increase to the water / ethylene glycol solution flowing through it. 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, allowing the heated water / ethylene glycol solution to heat the LNG from the LNG storage tank. The low-pressure water / ethylene glycol module of the cooling system is connected to the evaporator compressor unit, BOG heater and cooler of the fuel processing chamber for cooling the LNG storage tank. The third heat exchanger of the high-pressure water / ethylene glycol module of the heating system is connected to the LNG evaporator in the fuel processing chamber via a water / ethylene glycol pipeline. It is used to heat the LNG evaporator with the heated water / ethylene glycol solution, thereby heating the LNG from the LNG storage tank.

2. The water / ethylene glycol heating-cooling system for the LNG system of a passenger roll-on / roll-off 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 via a low-temperature water pipeline, and is used to provide the first heat exchanger with a low-temperature heat exchange medium.

3. The water / ethylene glycol heating-cooling system for the LNG system of a passenger roll-on / roll-off ship according to claim 2, characterized in that, In a low-temperature water cooling system, the temperature of the low-temperature water is 34~38℃.

4. The water / ethylene glycol heating-cooling system for the LNG system of a passenger roll-on / roll-off ship according to claim 1, characterized in that, The evaporator compressor unit includes at least one evaporator compressor.

5. The water / ethylene glycol heating-cooling system for the LNG system of a passenger roll-on / roll-off ship according to claim 1, characterized in that, The cooling system also includes multiple pumps.

6. A water / ethylene glycol heating-cooling method for a LNG system on a passenger roll-on / roll-off ship, characterized in that, The heating-cooling method employs the water / ethylene glycol heating-cooling system of the LNG system for passenger roll-on / roll-off ships according to any one of claims 1-5, and the heating-cooling method includes the following steps: 1) Cooling the 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. Then, the low-pressure water / ethylene glycol solution flows through the first heat exchanger to exchange energy with the cooling water from the low-temperature water cooling system, thereby cooling the water-ethylene glycol solution. The cooled water-ethylene glycol solution enters the fuel handling chamber and flows through the evaporative gas compressor unit and the BOG heater and cooler. The water-ethylene glycol solution absorbs the heat from the evaporative gas compressor unit and the BOG heater and cooler, thereby cooling the LNG in the LNG storage tank. 2) Heating the 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. Then, the high-pressure water / ethylene glycol solution flows through the second heat exchanger to exchange heat with the main engine cylinder liner water from the main engine cylinder liner, thereby achieving the first temperature rise of the water-ethylene glycol solution. After the first heating, the water-ethylene glycol solution flows through the third heat exchanger and undergoes secondary heat exchange with steam, thus achieving a second heating of the water-ethylene glycol solution. The water-glycol solution, after a second heating, enters the fuel processing chamber to heat the LNG evaporator, thus raising the temperature of the LNG.

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