Cold and heat utilization system in process of converting marine LNG (liquefied natural gas) into NG (natural gas)

Abstract

The invention discloses a cold and heat utilization system in the process of converting marine LNG into NG, and relates to the technical field of LNG ships, the cold and heat utilization system comprises an LNG vaporization heat exchange system, a gas engine tail gas heat exchange system, a temperature regulation and control system and a medium storage system; according to the scheme, cold energy generated in the ship LNG gasification heating process and heat energy generated by combustion of the gas engine are utilized, heat exchange is conducted through the heat exchange device (the surface air cooler) to replace an air conditioner, energy consumption is reduced, and refrigeration in summer and heating in winter are achieved. In the process, heat balance needs to be emphatically controlled, heat needed by LNG gasification heat exchange is met, and meanwhile cold energy and heat energy are fully utilized. The electric energy required by the heat exchange device (surface air cooler) is less and is far lower than the working energy consumption of an air conditioner, so that the energy consumption can be reduced and saved.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG ships, and more specifically to the technical field of a cold and heat utilization system for a process of converting ship-used LNG into NG. Background Art

[0002] Liquefied Natural Gas (LNG), whose main component is methane, is recognized as the cleanest fossil energy on earth. It is colorless, odorless, non-toxic and non-corrosive. Its volume is about 1 / 625 of the volume of the same amount of gaseous natural gas, and its mass is only about 45% of the same volume of water. Its manufacturing process is to purify the natural gas produced by the gas field, liquefy it through a series of ultra-low temperature processes, and then transport it by LNG ship. After burning, liquefied natural gas causes very little air pollution and releases a lot of heat, so liquefied natural gas is a relatively advanced energy source.

[0003] The patent with the publication number CN113405018A and the patent name "A LNG-powered ship" discloses the following content: A LNG-powered ship includes a hull and a fuel supply device detachably connected to the hull. A delivery pipeline is provided on the hull. The fuel supply device includes a frame, a tank body, at least one cold box, and a gas supply mechanism arranged one-to-one with the cold box. The frame has a storage space inside; the frame is detachably connected to the hull; the tank body is arranged in the storage space; the tank body is used to load LNG; the cold box is arranged in the storage space and is arranged in sequence with the tank body along the length direction of the frame; the gas supply mechanism includes a buffer tank, and a gasification and boosting unit, a pressure regulating unit, a filling pipeline, a connecting pipeline and a gas supply pipeline arranged in the cold box, the gasification and boosting unit is connected to the connecting pipeline, the pressure regulating unit is arranged downstream of the gasification and boosting unit, the buffer tank is arranged in the storage space, and the buffer tank is arranged downstream of the gasification and boosting unit, the gas supply pipeline is arranged downstream of the buffer tank to transport NG outward, and the gas supply pipeline is detachably connected to the delivery pipeline.

[0004] The patent with the publication number CN114109658B and the patent name "An Integrated Utilization System of Waste Heat from the Main Engine of LNG-Powered Ships and LNG Vaporization Cold Energy" discloses the following contents: including the NG evaporation side, LNG is sequentially pressurized, first-stage heat exchanged, second-stage pressurized, second-stage heat exchanged and third-stage heat exchanged to form a gaseous state; the first-stage Rankine cycle power generation unit, the second-stage Rankine cycle power generation unit and the third-stage transcritical Rankine cycle power generation unit are transversely nested, and the cold source of each unit is formed by the step-by-step heat exchange of LNG, and the flue gas is used as the heat source to form a two-stage pressurized, three-stage transversely nested Rankine cycle full power generation system. The system of the present invention has a compact structure, can meet the main engine intake pressure requirements and has a high system efficiency, reducing the operating cost of the ship.

[0005] In the above patents and the existing LNG ship industry, LNG can only be used by the engine after it is gasified and heated to NG at room temperature. A large amount of cold energy is released during the heat exchange process and is directly discharged to the outside through the heat exchange medium. At the same time, the heat generated by the combustion of the gas engine is directly discharged into the atmosphere through the exhaust gas, resulting in energy waste. Summary of the invention

[0006] The purpose of the present invention is to solve the technical problems of the cold energy generated by the existing LNG ship during the LNG gasification and heating process and the heat energy taken away by the tail gas emission. The present invention provides a cold and heat utilization system for the ship's LNG to NG process. At the same time, new equipment is replaced to reduce energy consumption and improve system operating costs.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] A cold and heat utilization system for the process of converting marine LNG into NG, comprising an LNG vaporization heat exchange system, a gas engine exhaust heat exchange system, a temperature control system and a medium storage system;

[0009] The air inlet of the gas engine exhaust heat exchange system is connected to the gas engine exhaust emission pipeline, and the air outlet of the gas engine exhaust heat exchange system is connected to the atmosphere;

[0010] The hot medium outlet of the gas engine exhaust heat exchange system is divided into two pipelines, one pipeline is connected to the hot medium inlet of the LNG vaporization heat exchange system, and the other pipeline is connected to the medium inlet of the temperature control system. The cold medium outlet of the LNG vaporization heat exchange system is connected to the medium inlet of the temperature control system and the medium return port of the medium storage system, and the medium outlet of the temperature control system is connected to the medium return port of the medium storage system;

[0011] The medium outlet of the medium storage system is connected to the cold medium inlet of the gas engine exhaust heat exchange system through a pipeline;

[0012] Each pipeline is equipped with a control valve.

[0013] Specifically, this solution utilizes the cold energy generated by the ship's LNG gasification heating process and the heat energy generated by the combustion of the gas engine, and uses a heat exchanger (surface cooler) to replace air conditioning, thereby reducing energy consumption and achieving cooling in summer and heating in winter. This process requires the focus on controlling the heat balance to meet the heat required for LNG gasification heat exchange, while making full use of cold energy and heat energy. Since the heat exchanger (surface cooler) requires less electrical energy to work, which is much lower than the working energy consumption of the air conditioner, it can reduce energy consumption. The cold capacity can be provided by other cryogenic liquids (such as liquid nitrogen, liquid oxygen) as a medium.

[0014] In one embodiment, the LNG vaporization heat exchange system includes a heat exchange tank shell, a coil arranged in the heat exchange tank shell, the heat exchange tank shell is provided with an LNG inlet (port A) and an NG outlet (port B) connected to both ends of the coil, the heat exchange tank shell is provided with a hot medium inlet (port C) and a cold medium outlet (port D) connected to the interior of the heat exchange tank shell, and a temperature transmitter is provided on the cold medium outlet (port D).

[0015] In one embodiment, the gas engine exhaust heat exchange system includes a plurality of heat source devices arranged in parallel, each heat source device includes an external shell and a coil arranged inside the external shell, the external shell is provided with an exhaust inlet and an exhaust outlet connected to both ends of the coil, and the external shell is provided with a cold medium inlet and a hot medium outlet connected to the inside of the external shell;

[0016] The outer shell is provided with a drain pipe which is in communication with the inside of the outer shell, and the drain pipe is provided with a drain valve;

[0017] Switch control valves are provided on both the cold medium inlet and the hot medium outlet.

[0018] In one embodiment, the gas engine exhaust heat exchange system further includes a steam pressure relief system, which includes a pressure relief pipe, and both ends of the pressure relief pipe are respectively connected to the interior of the external shell and the interior of the medium storage system.

[0019] In one embodiment, the medium storage system includes an expansion water tank, a medium inlet, a medium return port, a medium outlet, a steam return port, and a terrace area exhaust port, and the medium inlet, the medium return port, the medium outlet, the steam return port, and the terrace area exhaust port are all connected to the inside of the expansion water tank;

[0020] The medium inlet is connected to the gravity water tank, the medium outlet is connected to a water outlet pipe, a pump is provided on the water outlet pipe, and the water outlet pipe is connected to the cold medium inlet of the gas engine exhaust heat exchange system or the hot medium inlet (C port) of the heat exchange tank shell.

[0021] In one embodiment, the temperature control system includes a plurality of coolers arranged in parallel, each cooler includes a cooler body, a cooler medium inlet, a cooler medium outlet and a heat exchange device, the cooler medium inlet and the cooler medium outlet are respectively connected to the interior of the cooler body, and the heat exchange device is arranged at the bottom of the cooler body.

[0022] In one embodiment, the temperature control system includes two surface coolers arranged in parallel, the surface coolers include a first surface cooler and a second surface cooler, the medium inlet (E port) of the first surface cooler and the medium inlet (G port) of the second surface cooler are connected to the ninth pipe (L9 pipeline) through a pipeline, the ninth pipe (L9 pipeline) is divided into an eighth pipeline (L8 pipeline) and a seventh pipeline (L7 pipeline), and the eighth pipeline (L8 pipeline) and the seventh pipeline (L7 pipeline) are respectively provided with a second manual stop valve and a third manual stop valve;

[0023] The eighth pipeline (L8 pipeline) and the seventh pipeline (L7 pipeline) are connected to the cold medium outlet (D port) and the hot medium outlet of the gas engine exhaust heat exchange system respectively;

[0024] The medium outlet (F port) of the first cooler and the medium outlet (H port) of the second cooler are connected to the eleventh pipe (L11 pipeline) through pipelines.

[0025] In one embodiment, the gas engine exhaust heat exchange system includes two first heat source devices and a second heat source device arranged in parallel;

[0026] The medium outlet of the expansion water tank is connected to a twelfth pipeline (L12 pipeline), and a pump is arranged on the twelfth pipeline (L12 pipeline);

[0027] The outlet of the twelfth pipeline (L12 pipeline) is connected to the first pipeline (L1 pipeline) and the second pipeline (L2 pipeline), and the first pipeline (L1 pipeline) is connected to the cold medium inlet of the first heat source device and the second heat source device through the fourth pipeline (L4 pipeline) and the fifth pipeline (L5 pipeline) respectively;

[0028] The heat medium inlet of the first heat source device and the second heat source device is connected to the heat medium inlet (C port) of the heat exchange tank shell through the third pipeline (L3 pipeline), the second pipeline (L2 pipeline) is connected to the third pipeline (L3 pipeline), and a temperature control valve is provided at the connection between the third pipeline (L3 pipeline) and the second pipeline (L2 pipeline);

[0029] The heat medium inlets of the first heat source device and the second heat source device are also connected to the ninth pipe (L9 pipeline) through the seventh pipeline (L7 pipeline).

[0030] In one embodiment, it further includes a tenth pipeline (L10 pipeline) connected to the eighth pipeline (L8 pipeline) and the eleventh pipeline (L11 pipeline), and a first manual stop valve is provided on the tenth pipeline (L10 pipeline).

[0031] In one embodiment, the terrace area exhaust port of the expansion tank is connected to a thirteenth pipeline (L13 pipeline)

[0032] In this embodiment, the gas engine exhaust heat exchange system includes two first heat source devices and a second heat source device arranged in parallel; the temperature control system includes two surface coolers arranged in parallel, and the surface coolers include a first surface cooler and a second surface cooler. The specific practical process is as follows:

[0033] How summer cooling works:

[0034] LNG is heated and vaporized by the coils in the LNG vaporization heat exchange system and becomes NG for use by ship engines. The high-temperature medium (such as water, ethylene glycol or other refrigerants) that exchanges heat with LNG enters from the C port of the heat exchanger and exits from the D port. After absorbing the cold energy of LNG vaporization, the temperature decreases. At this time, the low-temperature medium flows in from the E port and G port of the heat exchange device (the first cooler and the cooler) through the L8 pipeline and the L9 pipeline, and flows out from the F port and H port, exchanges heat with the heat exchange device (the first cooler and the second cooler), and absorbs heat in the air through the heat exchange device (cooler fan), thereby reducing the indoor air temperature of the ship.

[0035] The medium in the pipeline is powered by the pump and circulates in the system. As the ship continues to consume NG during navigation, LNG is continuously vaporized and heated to provide cold energy, thus reducing the air temperature in each cabin of the ship.

[0036] When the indoor temperature continues to drop and reaches equilibrium, the indoor air no longer exchanges heat, the heat exchange device (surface cooler) cannot provide thermal energy, and the medium temperature for LNG heat exchange is insufficient. At this time, heating is required by the first heat source device or the second heat source device to provide the heat required for LNG vaporization.

[0037] During this process, the third stop valve is always closed. When one or more of the heat exchange devices (the first cooler and the second cooler) are operating normally, the opening of the first stop valve needs to be adjusted; if all the heat exchange devices (the first cooler and the second cooler) are faulty or closed, the first stop valve needs to be fully opened.

[0038] Winter heating working principle:

[0039] The heat for LNG gasification heating can only be obtained through the first heat source device or the second heat source device; at this time, the second stop valve needs to be closed and the third stop valve needs to be opened, and the heat required by the heat exchange device (the first surface cooler and the second surface cooler) is directly obtained from the first heat source device or the second heat source device.

[0040] Heat balance principle:

[0041] The pump is a variable frequency pump, which can adjust the medium flow and flow rate by adjusting the frequency of the pump;

[0042] When the temperature sensor detects that the NG gas does not meet the engine gas temperature, the temperature control valve is used to adjust the opening and closing degree to adjust the medium flow to pipelines L1 and L2 to achieve heat balance.

[0043] The gas generated in the first heat source device or the second heat source device is transported to the expansion water tank through the pipeline L6, and is led to the open-air area through the pipeline L13.

[0044] The beneficial effects of the present invention are as follows:

[0045] 1. This solution utilizes the cold energy generated by the ship's LNG gasification heating process and the heat energy generated by the combustion of the gas engine. At the same time, heat exchange is performed through a heat exchange device (surface cooler) instead of air conditioning, reducing energy consumption and achieving cooling in summer and heating in winter. This process requires the focus on controlling the heat balance to meet the heat required for LNG gasification heat exchange, while making full use of cold energy and heat energy. Since the amount of electricity required for the operation of the heat exchange device (surface cooler) is small, it is much lower than the operating energy consumption of the air conditioner, which can reduce energy consumption.

[0046] 2. A heat exchange device (surface cooler) and a heat source device are introduced to carry out heat exchange and achieve energy balance.

[0047] 3. The air supply temperature can be precisely controlled by adjusting the electric temperature control valve. The cold and heat energy in the heat exchange process can be fully recycled to achieve energy saving.

[0048] 4. In the heat exchange system of LNG gasification, by adding heat exchange devices (surface coolers), pipes and valves, the air conditioners in the ship's buildings can be replaced to achieve low energy consumption operation and low system cost. This system can be appropriately configured with the number of heat exchange devices (surface coolers) according to the amount of LNG required for the operation of the ship's main engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 It is a schematic diagram of the structure of the present invention;

[0051] Figure 2 It is a structural diagram of the LNG vaporization heat exchange system;

[0052] Figure 3 It is a schematic diagram of the structure of the expansion tank;

[0053] Figure 4 is a schematic diagram of the structure of the heat source device;

[0054] Figure numerals: 1-first surface cooler, 2-second surface cooler, 3-LNG vaporization heat exchange system, 4-first heat source device, 5-second heat source device, 6-pump, 7-expansion water tank, 8-first manual stop valve, 9-second manual stop valve, 10-third manual stop valve, 11-temperature control valve, 12-temperature transmitter. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and technical effects of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0056] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0057] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0058] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0059] Example 1

[0060] like Figure 1 As shown, this embodiment provides a cold and heat utilization system for the process of converting marine LNG into NG, including an LNG vaporization heat exchange system 3, a gas engine exhaust heat exchange system, a temperature control system and a medium storage system;

[0061] The air inlet of the gas engine exhaust heat exchange system is connected to the gas engine exhaust emission pipeline, and the air outlet of the gas engine exhaust heat exchange system is connected to the atmosphere;

[0062] The hot medium outlet of the gas engine exhaust heat exchange system is divided into two pipelines, one pipeline is connected to the hot medium inlet of the LNG vaporization heat exchange system 3, and the other pipeline is connected to the medium inlet of the temperature control system. The cold medium outlet of the LNG vaporization heat exchange system 3 is connected to the medium inlet of the temperature control system and the medium return port of the medium storage system, and the medium outlet of the temperature control system is connected to the medium return port of the medium storage system;

[0063] The medium outlet of the medium storage system is connected to the cold medium inlet of the gas engine exhaust heat exchange system through a pipeline;

[0064] Each pipeline is equipped with a control valve.

[0065] Specifically, this solution utilizes the cold energy generated by the ship's LNG gasification heating process and the heat energy generated by the combustion of the gas engine, and uses a heat exchanger (surface cooler) to replace air conditioning, thereby reducing energy consumption and achieving cooling in summer and heating in winter. This process requires the focus on controlling the heat balance to meet the heat required for LNG gasification heat exchange, while making full use of cold energy and heat energy. Since the heat exchanger (surface cooler) requires less electrical energy to work, which is much lower than the working energy consumption of the air conditioner, it can reduce energy consumption. The cold capacity can be provided by other cryogenic liquids (such as liquid nitrogen, liquid oxygen) as a medium.

[0066] Example 2

[0067] like Figure 1 As shown, this embodiment provides a cold and heat utilization system for the process of converting marine LNG into NG, including an LNG vaporization heat exchange system 3, a gas engine exhaust heat exchange system, a temperature control system and a medium storage system;

[0068] The air inlet of the gas engine exhaust heat exchange system is connected to the gas engine exhaust emission pipeline, and the air outlet of the gas engine exhaust heat exchange system is connected to the atmosphere;

[0069] The hot medium outlet of the gas engine exhaust heat exchange system is divided into two pipelines, one pipeline is connected to the hot medium inlet of the LNG vaporization heat exchange system 3, and the other pipeline is connected to the medium inlet of the temperature control system. The cold medium outlet of the LNG vaporization heat exchange system 3 is connected to the medium inlet of the temperature control system and the medium return port of the medium storage system, and the medium outlet of the temperature control system is connected to the medium return port of the medium storage system;

[0070] The medium outlet of the medium storage system is connected to the cold medium inlet of the gas engine exhaust heat exchange system through a pipeline;

[0071] Each pipeline is equipped with a control valve.

[0072] The LNG vaporization heat exchange system 3 includes a heat exchange tank shell, a coil arranged in the heat exchange tank shell, an LNG inlet (port A) and an NG outlet (port B) connected to both ends of the coil are arranged on the heat exchange tank shell, a hot medium inlet (port C) and a cold medium outlet (port D) connected to the inside of the heat exchange tank shell are arranged on the heat exchange tank shell, and a temperature transmitter 12 is arranged on the cold medium outlet (port D).

[0073] The gas engine exhaust heat exchange system includes a plurality of heat source devices arranged in parallel, each heat source device includes an external shell and a coil arranged inside the external shell, the external shell is provided with an exhaust gas inlet and an exhaust gas outlet connected to both ends of the coil, and the external shell is provided with a cold medium inlet and a hot medium outlet connected to the inside of the external shell;

[0074] The outer shell is provided with a drain pipe which is in communication with the inside of the outer shell, and the drain pipe is provided with a drain valve;

[0075] Switch control valves are provided on both the cold medium inlet and the hot medium outlet.

[0076] The gas engine exhaust heat exchange system also includes a steam pressure relief system, which includes a pressure relief pipe, and both ends of the pressure relief pipe are respectively connected to the inside of the external shell and the inside of the medium storage system.

[0077] The medium storage system includes an expansion water tank 7, a medium inlet, a medium return port, a medium outlet, a steam return port, and a terrace area exhaust port, and the medium inlet, the medium return port, the medium outlet, the steam return port, and the terrace area exhaust port are all connected to the inside of the expansion water tank 7;

[0078] The medium inlet is connected to the gravity water tank, and the medium outlet is connected to a water outlet pipe, on which a pump 6 is provided. The water outlet pipe is connected to the cold medium inlet of the gas engine exhaust heat exchange system or to the hot medium inlet (C port) of the heat exchange tank shell.

[0079] The temperature control system includes a plurality of surface coolers arranged in parallel, each surface cooler includes a surface cooler body, a surface cooler medium inlet, a surface cooler medium outlet and a heat exchange device, the surface cooler medium inlet and the surface cooler medium outlet are respectively connected to the inside of the surface cooler body, and the heat exchange device is arranged at the bottom of the surface cooler body.

[0080] Example 3

[0081] This embodiment is further optimized on the basis of Embodiment 2, specifically:

[0082] The temperature control system includes two surface coolers arranged in parallel, the surface coolers include a first surface cooler 1 and a second surface cooler 2, the medium inlet (E port) of the first surface cooler 1 and the medium inlet (G port) of the second surface cooler 2 are connected to the ninth pipe (L9 pipeline) through a pipeline, the ninth pipe (L9 pipeline) is divided into an eighth pipeline (L8 pipeline) and a seventh pipeline (L7 pipeline), and the eighth pipeline (L8 pipeline) and the seventh pipeline (L7 pipeline) are respectively provided with a second manual stop valve 9 and a third manual stop valve 10;

[0083] The eighth pipeline (L8 pipeline) and the seventh pipeline (L7 pipeline) are connected to the cold medium outlet (D port) and the hot medium outlet of the gas engine exhaust heat exchange system respectively;

[0084] The medium outlet (F port) of the first condenser 1 and the medium outlet (H port) of the second condenser 2 are connected to the eleventh pipe (L11 pipeline) through pipelines.

[0085] In one embodiment, the gas engine exhaust heat exchange system includes two first heat source devices 4 and second heat source devices 5 arranged in parallel;

[0086] The medium outlet of the expansion water tank 7 is connected to a twelfth pipeline (L12 pipeline), and a pump 6 is arranged on the twelfth pipeline (L12 pipeline);

[0087] The outlet of the twelfth pipeline (L12 pipeline) is connected to the first pipeline (L1 pipeline) and the second pipeline (L2 pipeline), and the first pipeline (L1 pipeline) is connected to the cold medium inlet of the first heat source device 4 and the second heat source device 5 through the fourth pipeline (L4 pipeline) and the fifth pipeline (L5 pipeline) respectively;

[0088] The heat medium inlet of the first heat source device 4 and the second heat source device 5 is connected to the heat medium inlet (C port) of the heat exchange tank shell through the third pipeline (L3 pipeline), the second pipeline (L2 pipeline) is connected to the third pipeline (L3 pipeline), and a temperature control valve 11 is provided at the connection between the third pipeline (L3 pipeline) and the second pipeline (L2 pipeline);

[0089] The heat medium inlets of the first heat source device 4 and the second heat source device 5 are also connected to the ninth pipe (L9 pipeline) through the seventh pipeline (L7 pipeline).

[0090] In one embodiment, it further includes a tenth pipeline (L10 pipeline) connected to the eighth pipeline (L8 pipeline) and the eleventh pipeline (L11 pipeline), and a first manual stop valve 8 is provided on the tenth pipeline (L10 pipeline).

[0091] The terrace area exhaust port of the expansion water tank 7 is connected with a thirteenth pipeline (L13 pipeline).

[0092] In this embodiment, the gas engine exhaust heat exchange system includes two first heat source devices 4 and second heat source devices 5 arranged in parallel; the temperature control system includes two surface coolers arranged in parallel, and the surface coolers include a first surface cooler 1 and a second surface cooler 2. The specific practical process is as follows:

[0093] How summer cooling works:

[0094] LNG is heated and vaporized by the coil in the LNG vaporization heat exchange system 3 and becomes NG for use by the ship's engine. The high-temperature medium (such as water, ethylene glycol or other refrigerant) that exchanges heat with LNG enters from the C port of the heat exchanger and exits from the D port. After absorbing the cold energy of LNG vaporization, the temperature decreases. At this time, the low-temperature medium flows into the E port and G port of the heat exchange device (the first cooler 1 and the cooler) through the L8 pipeline and the L9 pipeline, and flows out from the F port and H port, exchanges heat with the heat exchange device (the first cooler 1 and the second cooler 2), and absorbs heat in the air through the heat exchange device (cooler fan), thereby reducing the indoor air temperature of the ship.

[0095] The medium in the pipeline is circulated in the system by the power provided by the pump 6. As the ship continues to consume NG during navigation, LNG is continuously gasified and heated to provide cold energy, thereby reducing the air temperature in each cabin of the ship.

[0096] When the indoor temperature continues to drop and reaches equilibrium, the indoor air no longer exchanges heat, and the heat exchange device (surface cooler) cannot provide thermal energy. The medium temperature for LNG heat exchange is insufficient. At this time, it is necessary to heat the medium through the first heat source device 4 or the second heat source device 5 to provide the heat required for LNG vaporization.

[0097] During this process, the third stop valve is always closed. When one or more of the heat exchange devices (the first cooler 1 and the second cooler 2) are operating normally, the opening of the first stop valve needs to be adjusted; if all the heat exchange devices (the first cooler 1 and the second cooler 2) are faulty or closed, the first stop valve needs to be fully opened.

[0098] Winter heating working principle:

[0099] The heat for LNG gasification heating can only be obtained through the first heat source device 4 or the second heat source device 5; at this time, the second stop valve needs to be closed and the third stop valve needs to be opened, and the heat required by the heat exchange device (the first surface cooler 1 and the second surface cooler 2) is directly obtained from the first heat source device 4 or the second heat source device 5.

[0100] Heat balance principle:

[0101] The pump 6 is a variable frequency pump 6, and the medium flow rate and flow rate are adjusted by adjusting the frequency of the pump 6;

[0102] When the temperature sensor detects that the NG gas does not meet the engine gas temperature, the temperature control valve 11 is used to adjust the opening and closing degree to adjust the medium flow to the pipelines L1 and L2 to achieve heat balance.

[0103] The gas generated in the first heat source device 4 or the second heat source device 5 is transported to the expansion water tank 7 through the pipeline L6, and is led to the open-air area through the pipeline L13.

Claims

1. A cold and heat utilization system for converting marine LNG into NG, characterized in that: It includes an LNG vaporization heat exchange system (3), a gas engine exhaust heat exchange system, a temperature control system, and a medium storage system; The air inlet of the gas engine exhaust heat exchange system is connected to the gas engine exhaust emission pipeline, and the air outlet of the gas engine exhaust heat exchange system is connected to the atmosphere; The hot medium outlet of the gas engine exhaust heat exchange system is divided into two pipelines, one pipeline is connected to the hot medium inlet of the LNG vaporization heat exchange system (3), and the other pipeline is connected to the medium inlet of the temperature control system. The cold medium outlet of the LNG vaporization heat exchange system (3) is connected to the medium inlet of the temperature control system and the medium return port of the medium storage system, and the medium outlet of the temperature control system is connected to the medium return port of the medium storage system. The medium outlet of the medium storage system is connected to the cold medium inlet of the gas engine exhaust heat exchange system through a pipeline; Each pipeline is equipped with a control valve.

2. The cold and heat utilization system for converting marine LNG into NG according to claim 1, characterized in that: The LNG vaporization heat exchange system (3) comprises a heat exchange tank shell, a coil arranged in the heat exchange tank shell, the heat exchange tank shell is provided with an LNG inlet and an LNG outlet connected to both ends of the coil, the heat exchange tank shell is provided with a hot medium inlet and a cold medium outlet connected to the inside of the heat exchange tank shell, and the cold medium outlet is provided with a temperature transmitter (12).

3. The cold and heat utilization system for converting marine LNG into NG according to claim 2, characterized in that: The gas engine exhaust heat exchange system comprises a plurality of heat source devices arranged in parallel, each of the heat source devices comprises an outer shell and a coil arranged inside the outer shell, the outer shell is provided with an exhaust gas inlet and an exhaust gas outlet connected to both ends of the coil, and the outer shell is provided with a cold medium inlet and a hot medium outlet connected to the inside of the outer shell; The outer shell is provided with a drain pipe communicating with the interior of the outer shell, and the drain pipe is provided with a drain valve; The cold medium inlet and the hot medium outlet are both provided with switch control valves.

4. The cold and heat utilization system for converting marine LNG into NG according to claim 3, characterized in that: The gas engine exhaust heat exchange system further includes a steam pressure relief system, and the steam pressure relief system includes a pressure relief pipe, and two ends of the pressure relief pipe are respectively connected to the interior of the external shell and the interior of the medium storage system.

5. The cold and heat utilization system for converting marine LNG into NG according to claim 4, characterized in that: The medium storage system comprises an expansion water tank (7), a medium inlet, a medium return port, a medium outlet, a steam return port and a terrace area exhaust port, wherein the medium inlet, the medium return port, the medium outlet, the steam return port and the terrace area exhaust port are all in communication with the interior of the expansion water tank (7); The medium inlet is connected to a gravity water tank, the medium outlet is connected to a water outlet pipe, a pump (6) is provided on the water outlet pipe, and the water outlet pipe is connected to a cold medium inlet of a gas engine exhaust heat exchange system or to a hot medium inlet of a heat exchange tank shell.

6. The cold and heat utilization system for converting marine LNG into NG according to claim 5, characterized in that: The temperature control system includes a plurality of coolers arranged in parallel, each of the coolers includes a cooler body, a cooler medium inlet, a cooler medium outlet and a heat exchange device, the cooler medium inlet and the cooler medium outlet are respectively connected to the interior of the cooler body, and the heat exchange device is arranged at the bottom of the cooler body.

7. The cold and heat utilization system for converting marine LNG into NG according to claim 6, characterized in that: The temperature control system comprises two surface coolers arranged in parallel, the surface coolers comprising a first surface cooler (1) and a second surface cooler (2), the medium inlet of the first surface cooler (1) and the medium inlet of the second surface cooler (2) are connected to a ninth pipe through a pipeline, the ninth pipe is divided into an eighth pipe and a seventh pipe, and the eighth pipe and the seventh pipe are respectively provided with a second manual stop valve (9) and a third manual stop valve (10); The eighth pipeline and the seventh pipeline are respectively connected to the cold medium outlet and the hot medium outlet of the gas engine exhaust heat exchange system; The medium outlet of the first cooler (1) and the medium outlet of the second cooler (2) are connected to the eleventh pipe via a pipeline.

8. The cold and heat utilization system for converting marine LNG into NG according to claim 7, characterized in that: The gas engine exhaust heat exchange system comprises a first heat source device (4) and a second heat source device (5) which are arranged in parallel; The medium outlet of the expansion water tank (7) is connected to a twelfth pipeline, and a pump (6) is provided on the twelfth pipeline; The outlet of the twelfth pipeline is connected to the first pipeline and the second pipeline, and the first pipeline is connected to the cold medium inlet of the first heat source device (4) and the second heat source device (5) through the fourth pipeline and the fifth pipeline respectively; The heat medium inlets of the first heat source device (4) and the second heat source device (5) are connected to the heat medium inlet of the heat exchange tank shell through a third pipe, the second pipe is connected to the third pipe, and a temperature control valve (11) is provided at the connection between the third pipe and the second pipe; The heat medium inlets of the first heat source device (4) and the second heat source device (5) are also connected to the ninth pipe through the seventh pipe.

9. The cold and heat utilization system for converting marine LNG into NG according to claim 8, characterized in that: It also includes a tenth pipeline connected to the eighth pipeline and the eleventh pipeline, and a first manual stop valve (8) is arranged on the tenth pipeline.

10. The cold and heat utilization system for converting marine LNG into NG according to claim 9, characterized in that: The terrace area exhaust port of the expansion water tank (7) is connected to a thirteenth pipeline.

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