Cold energy power generation system suitable for LNG receiving station

Abstract

The invention discloses a cold energy power generation system suitable for an LNG receiving station. The system comprises a BOG-air energy cascade recovery processing system and a Brayton cycle power generation system, a turbo expander and an air compressor are of a horizontal structure, and the Brayton cycle power generation system and the BOG-air energy cascade recovery processing system are integrated; the Brayton cycle system is used for recovering LNG cold energy, the double-work exchanger is used for recovering pressure energy, and efficient gradient utilization of energy is achieved through cooperation of multiple devices. The device disclosed by the invention is simple in structure and high in practicability, realizes effective utilization of LNG cold energy and pressure energy in the BOG treatment process, realizes efficient utilization of energy, and has the characteristics of integration and low energy consumption. The purposes of saving energy, reducing consumption and improving efficiency are achieved, and good economic benefits and environmental protection benefits can be brought to production and operation of the LNG receiving station.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cold energy utilization, and particularly relates to a cold energy power generation system suitable for an LNG receiving station. BACKGROUND

[0002] With the rapid development of social economy and the increasing demand for energy, the optimization of industrial structure aiming at carbon peak and carbon neutrality, it is urgent to promote the development of green and low-carbon energy. Under the background of energy structure transformation to low carbon, LNG (liquefied natural gas) as a clean, efficient and low-pollution energy, its consumption continues to grow. Its advantages are increasingly valued, among which LNG is easy to transport and store, and its proportion in the energy market is increasing. LNG receiving station as an important link in LNG industry chain, the efficient use of energy in its operation process becomes the research focus. LNG cold energy is a high-quality clean energy, and one ton of LNG can release about 240kW·h of cold energy when it is gasified, but the utilization efficiency of cold energy for power generation in the traditional process is not high, and it is of great significance to fully and efficiently utilize LNG cold energy.

[0003] In the LNG receiving station, due to the influence of equipment heat leakage and other factors, evaporation gas (BOG) will inevitably be produced. If the BOG in the storage tank is not treated in time, it will cause overpressure of the storage tank and cause danger, and the treatment method of BOG is related to the recycling effect of resources. However, most of the existing BOG treatment systems have problems such as high energy consumption and serious waste of cold energy. Among them, the BOG compressor as the core equipment of the BOG treatment system usually adopts motor drive, which needs to consume a lot of electric energy.

[0004] In view of the above situation, by combining the Brayton cycle power generation system and the BOG-air energy cascade recovery treatment system, the BOG is put into the mixed gas system, and after accurate control by the inlet flow regulating valve, it is mixed with the cold energy exchanged medium pressure natural gas in proportion, and the pressure energy is recovered (replaces part of the compressor energy consumption) in the work exchanger, and its low temperature characteristics (-140℃) can assist cooling circulating air, realizing the cascade utilization of "pressure energy-cold energy", avoiding the high energy consumption and cold energy waste of the traditional system from the root, achieving the purpose of energy saving and efficiency improvement. SUMMARY

[0005] To address the aforementioned issues of BOG processing and LNG cold energy waste at LNG receiving terminals, this invention proposes a cold energy power generation system suitable for LNG receiving terminals. By incorporating BOG into the mixed gas regulation system and utilizing an independent flow regulating valve group to dynamically mix it with cold natural gas, the system recovers its pressure energy in the power exchanger to compensate for system energy consumption, replacing the traditional motor-driven BOG compressor. This significantly reduces electricity consumption. Relying on the linkage between a horizontal turbine expander and a centrifugal compressor, the system converts LNG cold energy into the power energy of air circulation, realizing the transformation of cold energy from "direct emission" to "cascade utilization," ultimately achieving efficient synergy between BOG processing and cold energy recovery.

[0006] The technical solution adopted in this invention is as follows:

[0007] A cold energy power generation system suitable for LNG receiving terminals, comprising a BOG-air energy cascade recovery system and a Brayton cycle power generation system.

[0008] The BOG-Air Energy Cascade Recovery and Processing System includes an LNG storage tank, BOG pipeline, first mixer, first heat exchanger, second heat exchanger, first distributor, second mixer, low-pressure natural gas export unit, first power exchanger, second power exchanger, second distributor, air input unit, third mixer, and fourth mixer.

[0009] The Brayton cycle power generation system includes a first buffer tank, an air compressor, a third heat exchanger, a seawater pump, a turboexpander, an electric motor, a second buffer tank, and a third distributor.

[0010] Furthermore, the LNG storage tank includes a BOG outlet and an in-tank pump. The BOG outlet is connected to the inlet of the first mixer via a BOG pipeline, and the cold flow outlet of the first heat exchanger is connected to the inlet of the first mixer. The outlet of the first mixer is connected to the cold flow inlet of the second heat exchanger, and the cold flow outlet of the second heat exchanger is connected to the inlet of the first distributor. The first branch of the first distributor is connected to the natural gas inlet of the first power exchanger, and the second branch of the first distributor is connected to the natural gas inlet of the second power exchanger. The first branch of the second mixer is connected to the natural gas outlet of the first power exchanger, and the second branch of the second mixer is connected to the natural gas outlet of the second power exchanger. The first branch of the air input unit is connected to the air inlet of the first power exchanger, and the second branch of the air input unit is connected to the air inlet of the second power exchanger. The first branch of the third mixer is connected to the air outlet of the first power exchanger, and the second branch of the third mixer is connected to the air outlet of the second power exchanger.

[0011] Furthermore, the heat outlet of the first heat exchanger is connected to the inlet of the fourth mixer; the heat outlet of the second heat exchanger is connected to the inlet of the fourth mixer; and the outlet of the third mixer is connected to the inlet of the fourth mixer.

[0012] Furthermore, the outlet of the fourth mixer is connected to the inlet of the first buffer tank, the outlet of the first buffer tank is connected to the inlet of the air compressor, the outlet of the air compressor is connected to the cold flow inlet of the third heat exchanger, the cold flow outlet of the third heat exchanger is connected to the inlet of the turbine expander, the outlet of the turbine expander is connected to the outlet of the second buffer tank; the outlet of the second buffer tank is connected to the inlet of the third distributor; the first branch of the third distributor is connected to the hot flow inlet of the first heat exchanger, and the second branch of the third distributor is connected to the hot flow inlet of the second heat exchanger.

[0013] Furthermore, a first flow regulating valve is installed on the BOG pipeline, and a second flow regulating valve is installed between the cold flow outlet of the first heat exchanger and the inlet of the first mixer; the outlet of the first flow regulating valve and the outlet of the second flow regulating valve merge and are connected to the inlet of the first mixer.

[0014] Furthermore, a pressure regulating valve is installed between the cold flow outlet of the second heat exchanger and the inlet of the first distributor; a first butterfly valve is installed on the first branch of the first distributor, and a third butterfly valve is installed on the second branch of the first distributor; a second butterfly valve is installed on the first branch of the second mixer, and a fourth butterfly valve is installed on the second branch of the second mixer; the outlet of the second mixer is connected to a low-pressure natural gas export unit.

[0015] Furthermore, a sixth butterfly valve is installed on the first branch of the air input unit, and an eighth butterfly valve is installed on the second branch of the air input unit; a fifth butterfly valve is installed on the first branch of the third mixer, and a seventh butterfly valve is installed on the second branch of the third mixer.

[0016] Furthermore, a third flow regulating valve is installed between the outlet of the third mixer and the inlet of the fourth mixer; a fourth flow regulating valve is installed between the heat outlet of the second heat exchanger and the inlet of the fourth mixer; a fifth flow regulating valve is installed between the heat outlet of the first heat exchanger and the inlet of the fourth mixer; the outlet of the third flow regulating valve, the outlet of the fourth flow regulating valve, and the outlet of the fifth flow regulating valve are combined and then connected to the inlet of the fourth mixer.

[0017] Furthermore, an automatic venting valve is installed between the outlet of the turbine expander and the outlet of the second buffer tank.

[0018] Furthermore, the heat inlet of the third heat exchanger is connected to the seawater pump; the turboexpander is connected to the electric motor via a coupling; both the turboexpander and the air compressor are horizontal structures.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] This invention relates to a cold energy power generation system suitable for LNG receiving terminals. The power converter directly converts the pressure energy of the mixture of BOG (Boiled Gas) and cold natural gas into mechanical work, assisting in driving the air circulation system. This system works in conjunction with the cold energy recovered by the turbine expander to compensate for the power consumption of air compression, replacing the energy consumption of the motor drive in traditional BOG compressors. This system has a reasonable structure and strong practicality, achieving the dual goals of energy saving and system efficiency improvement while efficiently recovering LNG cold energy and BOG pressure energy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a cold energy power generation system suitable for LNG receiving terminals according to the present invention.

[0022] In the diagram: 1 is the LNG storage tank, 2 is the BOG pipeline, 3 is the first flow control valve, 4 is the first mixer, 5 is the in-tank pump, 6 is the first heat exchanger, 7 is the second flow control valve, 8 is the second heat exchanger, 9 is the pressure control valve, 10 is the first distributor, 11 is the first butterfly valve, 12 is the second butterfly valve, 13 is the third butterfly valve, 14 is the fourth butterfly valve, 15 is the second mixer, 16 is the low-pressure natural gas export unit, 17 is the first power exchanger, 18 is the second power exchanger, 19 is the fifth butterfly valve, 2 0 is the sixth butterfly valve, 21 is the seventh butterfly valve, 22 is the eighth butterfly valve, 23 is the second distributor, 24 is the air input unit, 25 is the third mixer, 26 is the third flow control valve, 27 is the fourth flow control valve, 28 is the fifth flow control valve, 29 is the fourth mixer, 30 is the first buffer tank, 31 is the air compressor, 32 is the third heat exchanger, 33 is the seawater pump, 34 is the turbine expander, 35 is the electric motor, 36 is the automatic exhaust valve, 37 is the second buffer tank, and 38 is the third distributor. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] The following is combined Figure 1The specific embodiments of the present invention are described below.

[0026] This invention provides a cold energy power generation system suitable for LNG receiving terminals, which includes a BOG-air energy cascade recovery system and a Brayton cycle power generation system.

[0027] The BOG-Air Energy Cascade Recovery and Processing System includes an LNG storage tank 1, a BOG pipeline 2, a first mixer 4, a first heat exchanger 6, a second heat exchanger 8, a first distributor 10, a second mixer 15, a low-pressure natural gas export unit 16, a first power exchanger 17, a second power exchanger 18, a second distributor 23, an air input unit 24, a third mixer 25, and a fourth mixer 29.

[0028] The Bretton cycle power generation system includes a first buffer tank 30, an air compressor 31, a third heat exchanger 32, a seawater pump 33, a turbine expander 34, an electric motor 35, a second buffer tank 37, and a third distributor 38.

[0029] LNG storage tank 1 includes a BOG outlet and an in-tank pump 5. The vaporized gas (i.e. gaseous natural gas) of LNG storage tank 1 is discharged through the BOG outlet, and the liquefied natural gas of LNG storage tank 1 is discharged through the outlet of the in-tank pump 5.

[0030] The BOG outlet of LNG storage tank 1 is connected to the inlet of the first mixer 4 through BOG pipeline 2, and the cold flow outlet of the first heat exchanger 6 is connected to the inlet of the first mixer 4.

[0031] Furthermore, a first flow regulating valve 3 is installed on the BOG pipeline 2, and a second flow regulating valve 7 is installed between the cold flow outlet of the first heat exchanger 6 and the inlet of the first mixer 4; the outlet of the first flow regulating valve 3 and the outlet of the second flow regulating valve 7 are connected to the inlet of the first mixer 4 after they merge.

[0032] The outlet of the first mixer 4 is connected to the cold flow inlet of the second heat exchanger 8, and the cold flow outlet of the second heat exchanger 8 is connected to the inlet of the first distributor 10.

[0033] Furthermore, a pressure regulating valve 9 is provided between the cold flow outlet of the second heat exchanger 8 and the inlet of the first distributor 10.

[0034] The first branch of the first splitter 10 is connected to the natural gas inlet of the first power exchanger 17, and the second branch of the first splitter 10 is connected to the natural gas inlet of the second power exchanger 18.

[0035] Furthermore, a first butterfly valve 11 is provided on the first branch of the first diverter 10, and a third butterfly valve 13 is provided on the second branch of the first diverter 10.

[0036] The first branch of the second mixer 15 is connected to the natural gas outlet of the first power exchanger 17, and the second branch of the second mixer 15 is connected to the natural gas outlet of the second power exchanger 18.

[0037] Furthermore, a second butterfly valve 12 is provided on the first branch of the second mixer 15, and a fourth butterfly valve 14 is provided on the second branch of the second mixer 15.

[0038] The outlet of the second mixer 15 is connected to a low-pressure natural gas export unit 16.

[0039] The first branch of the air input unit 24 is connected to the air inlet of the first power exchanger 17, and the second branch of the air input unit 24 is connected to the air inlet of the second power exchanger 18.

[0040] Furthermore, a sixth butterfly valve 20 is provided on the first branch of the air input unit 24, and an eighth butterfly valve 22 is provided on the second branch of the air input unit 24.

[0041] The first branch of the third mixer 25 is connected to the air outlet of the first power exchanger 17, and the second branch of the third mixer 25 is connected to the air outlet of the second power exchanger 18.

[0042] Furthermore, a fifth butterfly valve 19 is provided on the first branch of the third mixer 25, and a seventh butterfly valve 21 is provided on the second branch of the third mixer 25.

[0043] The outlet of the third mixer 25 is connected to the inlet of the fourth mixer 29.

[0044] Furthermore, a third flow regulating valve 26 is provided between the outlet of the third mixer 25 and the inlet of the fourth mixer 29.

[0045] The heat outlet of the second heat exchanger 8 is connected to the inlet of the fourth mixer 29.

[0046] Furthermore, a fourth flow regulating valve 27 is provided between the heat outlet of the second heat exchanger 8 and the inlet of the fourth mixer 29.

[0047] The heat outlet of the first heat exchanger 6 is connected to the inlet of the fourth mixer 29.

[0048] Furthermore, a fifth flow regulating valve 28 is provided between the heat outlet of the first heat exchanger 6 and the inlet of the fourth mixer 29.

[0049] The outlet of the third flow regulating valve 26, the outlet of the fourth flow regulating valve 27, and the outlet of the fifth flow regulating valve 28 are connected to the inlet of the fourth mixer 29.

[0050] The outlet of the fourth mixer 29 is connected to the inlet of the first buffer tank 30, the outlet of the first buffer tank 30 is connected to the inlet of the air compressor 31, the outlet of the air compressor 31 is connected to the cold flow inlet of the third heat exchanger 32, the cold flow outlet of the third heat exchanger 32 is connected to the inlet of the turbine expander 34, and the outlet of the turbine expander 34 is connected to the outlet of the second buffer tank 37.

[0051] Furthermore, an automatic exhaust valve 36 is provided between the outlet of the turbine expander 34 and the outlet of the second buffer tank 37.

[0052] The outlet of the second buffer tank 37 is connected to the inlet of the third distributor 38.

[0053] The first branch of the third splitter 38 is connected to the heat inlet of the first heat exchanger 6, and the second branch of the third splitter 38 is connected to the heat inlet of the second heat exchanger 8.

[0054] Furthermore, the heat inlet of the third heat exchanger 32 is connected to the seawater pump 33.

[0055] Furthermore, the turbine expander 34 and the air compressor 31 are horizontal structures.

[0056] Furthermore, the turbine expander 34 is connected to the electric motor 35 via a coupling.

[0057] Furthermore, the working fluid in a Brayton cycle power generation system is air.

[0058] The liquefied natural gas in LNG storage tank 1 exchanges heat with the air in the first branch of the third splitter 38 in the first heat exchanger 6. The liquefied natural gas after heat exchange merges with the evaporated gas (i.e., gaseous natural gas) in LNG storage tank 1 at the inlet of the first mixer 4. The merged natural gas exchanges heat with the air in the second branch of the third splitter 38 in the second heat exchanger 8.

[0059] A portion of the heat-exchanged natural gas enters the first power exchanger 17 through the first branch of the first distributor 10, where it exchanges heat with the air entering the first power exchanger 17 through the first branch of the air input unit 24, and then flows out through the natural gas outlet of the first power exchanger 17. The other portion of the heat-exchanged natural gas enters the second power exchanger 18 through the second branch of the first distributor 10, where it exchanges heat with the air entering the second power exchanger 18 through the second branch of the air input unit 24, and then flows out through the natural gas outlet of the second power exchanger 18. The outflowing natural gas converges at the inlet of the second mixer 15, and then flows through the second mixer 15 to the low-pressure natural gas export unit 16, completing the natural gas supply.

[0060] After heat exchange in the first heat exchanger 17 and the second heat exchanger 18, the air converges at the inlet of the third mixer 25 and then flows to the fourth mixer 29. Air in the first branch of the third splitter 38, after heat exchange in the first heat exchanger 6, also flows to the fourth mixer 29. Air in the second branch of the third splitter 38, after heat exchange in the second heat exchanger 8, also flows to the fourth mixer 29. In other words, the three streams of heat-exchanged air converge at the inlet of the fourth mixer 29 and then enter the first buffer tank 30.

[0061] Air exiting from the first buffer tank 30 enters the air compressor 31 for pressurization. The pressurized air then flows from the air compressor 31 to the third heat exchanger 32, where it exchanges heat with seawater supplied by the seawater pump 33. The heat-exchanged air then enters the turboexpander 34 to perform work and drive a generator to produce electricity, which in turn provides power to the air compressor 31.

[0062] The air exiting the turbine expander 34 enters the second buffer tank 37, and then enters the first heat exchanger 6 and the second heat exchanger 8 through the branch of the third distributor 38 for the next round of heat cycle.

[0063] The present invention relates to a cold energy power generation system suitable for LNG receiving terminals, which can effectively handle BOG generated by LNG receiving terminals. The cold energy power generation system directly recovers BOG pressure energy through a power converter (conversion efficiency of over 85%). Combined with staged heat exchange by the first heat exchanger 6 and the second heat exchanger 8, the LNG cold energy recovery rate is increased to 65%-85%, representing a 15-35 percentage point improvement in energy savings compared to the traditional system's 20%. The cold energy power generation system integrates the air compressor 31, turbo expander 34, and independent flow regulating valve group in a modular layout, eliminating the need for a complex electrical control system, resulting in a more compact structure and a 10%-20% reduction in operation and maintenance costs. Through a "no phase change throughout the gaseous working fluid" design, the cold energy power generation system avoids heat loss caused by phase changes in traditional systems, and can still operate stably under BOG flow fluctuations of ±30%, making it more practical. Overall, this cold energy power generation system not only achieves deep energy savings by reducing electricity consumption by 30%-50%, but also reduces carbon emissions by about 25% through the synergistic recovery of cold energy and pressure energy, bringing more significant economic benefits and environmental value to LNG receiving terminals.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A cold energy power generation system suitable for LNG receiving terminals, the system comprising a BOG-air energy cascade recovery system and a Brayton cycle power generation system; characterized in that: The BOG-air energy cascade recovery system includes an LNG storage tank (1), a BOG pipeline (2), a first mixer (4), a first heat exchanger (6), a second heat exchanger (8), a first distributor (10), a second mixer (15), a low-pressure natural gas export unit (16), a first power exchanger (17), a second power exchanger (18), a second distributor (23), an air input unit (24), a third mixer (25), and a fourth mixer (29). The Brayton cycle power generation system includes a first buffer tank (30), an air compressor (31), a third heat exchanger (32), a seawater pump (33), a turbine expander (34), an electric motor (35), a second buffer tank (37), and a third distributor (38).

2. A cold energy power generation system suitable for LNG receiving terminals according to claim 1, characterized in that: The LNG storage tank (1) includes a BOG outlet and an in-tank pump (5). The BOG outlet is connected to the inlet of the first mixer (4) via the BOG pipeline (2). The cold flow outlet of the first heat exchanger (6) is connected to the inlet of the first mixer (4). The outlet of the first mixer (4) is connected to the cold flow inlet of the second heat exchanger (8). The cold flow outlet of the second heat exchanger (8) is connected to the inlet of the first distributor (10). The first branch of the first distributor (10) is connected to the natural gas inlet of the first power exchanger (17). The second branch of the first distributor (10) is connected to the natural gas inlet of the second power exchanger (18). The first branch of the second mixer (15) is connected to the natural gas outlet of the first power exchanger (17), and the second branch of the second mixer (15) is connected to the natural gas outlet of the second power exchanger (18); the first branch of the air input unit (24) is connected to the air inlet of the first power exchanger (17), and the second branch of the air input unit (24) is connected to the air inlet of the second power exchanger (18); the first branch of the third mixer (25) is connected to the air outlet of the first power exchanger (17), and the second branch of the third mixer (25) is connected to the air outlet of the second power exchanger (18).

3. A cold energy power generation system suitable for LNG receiving terminals according to claim 2, characterized in that: The heat outlet of the first heat exchanger (6) is connected to the inlet of the fourth mixer (29); the heat outlet of the second heat exchanger (8) is connected to the inlet of the fourth mixer (29); and the outlet of the third mixer (25) is connected to the inlet of the fourth mixer (29).

4. A cold energy power generation system suitable for LNG receiving terminals according to claim 3, characterized in that: The outlet of the fourth mixer (29) is connected to the inlet of the first buffer tank (30), the outlet of the first buffer tank (30) is connected to the inlet of the air compressor (31), the outlet of the air compressor (31) is connected to the cold flow inlet of the third heat exchanger (32), the cold flow outlet of the third heat exchanger (32) is connected to the inlet of the turbine expander (34), the outlet of the turbine expander (34) is connected to the outlet of the second buffer tank (37); the outlet of the second buffer tank (37) is connected to the inlet of the third distributor (38); the first branch of the third distributor (38) is connected to the hot flow inlet of the first heat exchanger (6), and the second branch of the third distributor (38) is connected to the hot flow inlet of the second heat exchanger (8).

5. A cold energy power generation system suitable for LNG receiving terminals according to claim 4, characterized in that: A first flow regulating valve (3) is provided on the BOG pipeline (2), and a second flow regulating valve (7) is provided between the cold flow outlet of the first heat exchanger (6) and the inlet of the first mixer (4); the outlet of the first flow regulating valve (3) and the outlet of the second flow regulating valve (7) are connected to the inlet of the first mixer (4) after they merge.

6. A cold energy power generation system suitable for LNG receiving terminals according to claim 4, characterized in that: A pressure regulating valve (9) is provided between the cold flow outlet of the second heat exchanger (8) and the inlet of the first distributor (10); a first butterfly valve (11) is provided on the first branch of the first distributor (10), and a third butterfly valve (13) is provided on the second branch of the first distributor (10); a second butterfly valve (12) is provided on the first branch of the second mixer (15), and a fourth butterfly valve (14) is provided on the second branch of the second mixer (15); the outlet of the second mixer (15) is connected to the low-pressure natural gas export unit (16).

7. A cold energy power generation system suitable for LNG receiving terminals according to claim 4, characterized in that: The first branch of the air input unit (24) is provided with a sixth butterfly valve (20), and the second branch of the air input unit (24) is provided with an eighth butterfly valve (22); the first branch of the third mixer (25) is provided with a fifth butterfly valve (19), and the second branch of the third mixer (25) is provided with a seventh butterfly valve (21).

8. A cold energy power generation system suitable for LNG receiving terminals according to claim 4, characterized in that: A third flow regulating valve (26) is provided between the outlet of the third mixer (25) and the inlet of the fourth mixer (29); a fourth flow regulating valve (27) is provided between the heat outlet of the second heat exchanger (8) and the inlet of the fourth mixer (29); a fifth flow regulating valve (28) is provided between the heat outlet of the first heat exchanger (6) and the inlet of the fourth mixer (29); the outlet of the third flow regulating valve (26), the outlet of the fourth flow regulating valve (27), and the outlet of the fifth flow regulating valve (28) are connected to the inlet of the fourth mixer (29).

9. A cold energy power generation system suitable for LNG receiving terminals according to claim 4, characterized in that: An automatic exhaust valve (36) is provided between the outlet of the turbine expander (34) and the outlet of the second buffer tank (37).

10. A cold energy power generation system suitable for LNG receiving terminals according to claim 4, characterized in that: The heat inlet of the third heat exchanger (32) is connected to the seawater pump (33); the turbine expander (34) is connected to the electric motor (35) via a coupling; both the turbine expander (34) and the air compressor (31) are horizontal structures.

Images