Water / ethylene glycol heating-cooling system and method for ro-ro ship LNG system

Abstract

Provided in the present application are a water / ethylene glycol heating-cooling system and method for a Ro-Ro ship LNG system. The Ro-Ro ship is an LNG-diesel dual-fuel system, and comprises a fuel treatment chamber and an LNG storage tank; 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; the low-temperature water cooling system is connected to the low-pressure water / ethylene glycol module; the heating system comprises a high-pressure water / ethylene glycol module, a main engine jacket water unit and a steam generator; the low-pressure water / ethylene glycol module is connected to an boil-off gas compressor unit, a BOG heater and a cooler of the fuel treatment chamber; the high-pressure water / ethylene glycol module is connected to an LNG evaporator of the fuel treatment chamber.

Description

Water / ethylene glycol heating-cooling system and method for LNG systems in passenger roll-on / roll-off ships

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202411701203.3, filed on November 26, 2024, and incorporates the disclosure of the aforementioned patent application as part of this application. Technical Field

[0003] This application 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

[0004] The existing ethylene glycol heating and cooling system for passenger roll-on / roll-off ships is shown below.

[0005] 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.

[0006] 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

[0007] This application provides a water / ethylene glycol heating-cooling system and method for a LNG system of a passenger roll-on / roll-off ship. The method involves adding a heating system and a cooling system to the LNG system so that the LNG coming out of the LNG storage tank gradually heats up 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.

[0008] To achieve the above objectives, this application adopts the following technical solution.

[0009] In a first aspect, this application provides a water / ethylene glycol heating-cooling system for a ro-ro passenger ship's LNG system. The ro-ro passenger ship uses an LNG-diesel dual-fuel system, which 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.

[0010] 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;

[0011] 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;

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] As an optional implementation, in the low-temperature water cooling system, the temperature of the low-temperature water is 34~38℃.

[0017] In this application, the low-temperature water is cooled by seawater to achieve the low temperature.

[0018] 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.

[0019] 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.

[0020] As an optional implementation, the evaporator compressor unit includes at least one evaporator compressor.

[0021] In this application, 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] As an optional implementation, the cooling system also includes multiple pumps.

[0028] 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.

[0029] 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.

[0030] In this application, 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.

[0031] Secondly, this application 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 includes the following steps:

[0032] 1) Cooling the LNG:

[0033] 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.

[0034] 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.

[0035] 2) Heating the LNG:

[0036] 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.

[0037] 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.

[0038] 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.

[0039] In this application, in step 1), the water-ethylene glycol solution flows sequentially through the evaporator gas compressor unit and the BOG heater and cooler in the fuel processing chamber, and absorbs the heat of the evaporator 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.

[0040] In this application, the temperature of the water-glycol solution after the second heating has reached the required level, and the water-glycol solution at this temperature can be used to heat the LNG evaporator.

[0041] In this application, the above-mentioned technical features can be freely combined to form new technical solutions, provided that they do not conflict with each other.

[0042] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0043] The water / ethylene glycol heating-cooling system for the LNG system of the passenger roll-on / roll-off ship provided in this application adopts the method of adding a heating system and a cooling system to the LNG system so that the LNG coming out of the LNG storage tank gradually heats up to meet the usage requirements, so that it can be directly used by the main engine and auxiliary engines. In addition, the heating-cooling system enables the LNG storage tank to meet the storage requirements of liquid LNG. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 shows a schematic diagram of the cooling process of the water / ethylene glycol heating-cooling system in Embodiment 1 of this application;

[0046] Figure 2 shows a schematic diagram of the heating process of the water / ethylene glycol heating-cooling system in Embodiment 1 of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application 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 application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] 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.

[0049] Example 1

[0050] A water / ethylene glycol heating-cooling system for a passenger ro-ro LNG system is disclosed. 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 water / ethylene glycol heating-cooling system includes a water / ethylene glycol unit, a cooling system, and a heating system. In this embodiment, the fuel handling chamber includes two evaporative gas compressor units, a BOG (boil-off gas) 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.

[0051] 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.

[0052] As shown in Figure 1, the cooling system includes a cryogenic water cooling system and a low-pressure water / ethylene glycol module. In this embodiment, 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, used to provide a cryogenic heat exchange medium to 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 via a water / ethylene glycol pipeline, used to allow the water / ethylene glycol solution to be cooled by passing through the first heat exchanger.

[0053] 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.

[0054] 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.

[0055] As shown in Figure 2, the heating system includes a high-pressure water / ethylene glycol module, a main engine cylinder liner water unit, and a steam generator. In this embodiment, the high-pressure water / ethylene glycol module includes a pressure controller, a second heat exchanger, and a third heat exchanger.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Example 2

[0060] 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:

[0061] S1. Cooling the LNG:

[0062] The water-ethylene glycol solution enters the low-pressure water / ethylene glycol module for pressure control (specifically, the water-ethylene glycol solution enters the low-pressure water / ethylene glycol module for pressure control of the low-pressure water / ethylene glycol module), 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.

[0063] 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.

[0064] S2. Heating the LNG:

[0065] The water-ethylene glycol solution enters the high-pressure water / ethylene glycol module for pressure control (specifically, the water-ethylene glycol solution enters the high-pressure water / ethylene glycol module for pressure control of the low-pressure water / ethylene glycol module), and then 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;

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] The above are preferred embodiments of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

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 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; 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 low-pressure water / glycol module of the cooling system is connected to the evaporative gas compressor unit, BOG heater, and cooler in the fuel processing chamber for cooling the LNG storage compartment; and 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.

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 any one of claims 1-3, characterized in that, 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 in the first heat exchanger, thereby lowering the temperature of the water / ethylene glycol solution; and 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.

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 evaporator compressor unit includes at least one evaporator compressor.

6. 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 water / ethylene glycol pipeline is connected in sequence 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. The main engine cylinder liner water unit is connected to the second heat exchanger of the high-pressure water / ethylene glycol module, and is used to initially heat the water / ethylene glycol solution flowing through the second heat exchanger; and The steam generator is connected to the third heat exchanger of the high-pressure water / ethylene glycol module via a steam pipeline, and is used to heat the water / ethylene glycol solution flowing through the third heat exchanger for the second time.

7. The water / glycol heating-cooling system for a ro-ro LNG system 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 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.

8. The water / glycol heating-cooling system for a ro-ro LNG system 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 in the fuel processing chamber via a water / ethylene glycol pipeline. It is used to heat the LNG evaporator by contacting the heated water / ethylene glycol solution, thereby heating the LNG from the LNG storage tank.

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

10. A water / ethylene glycol heating-cooling method for an 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 1-9, and the heating-cooling method includes the following steps: 1) Cooling the LNG: A water-ethylene glycol solution enters a low-pressure water / ethylene glycol module for pressure control, resulting in a low-pressure water / ethylene glycol solution. This low-pressure water / ethylene glycol solution then flows through a first heat exchanger, exchanging energy with cooling water from a low-temperature water cooling system to cool 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. The water-ethylene glycol solution, after its initial heating, flows through a third heat exchanger where it undergoes secondary heat exchange with steam, achieving a second heating of the 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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