Safe energy-saving system suitable for LNG receiving station

Abstract

The invention relates to a safe energy-saving system suitable for an LNG receiving station. The safe energy-saving system comprises a photovoltaic photo-thermal integrated system and a refrigerant expansion power generation system. The photovoltaic and photo-thermal integrated system comprises a photovoltaic power generation device and a heat storage liquid circulation loop, a heat exchange part is arranged between the heat storage liquid circulation loop and the photovoltaic power generation device and is used for absorbing heat generated in the power generation process of the photovoltaic power generation device and heating the heat storage liquid; the refrigerant expansion power generation system is provided with a refrigerant circulation loop, and a heat exchange part is also arranged between the refrigerant circulation loop and the heat storage liquid circulation loop so as to absorb heat of the heat storage liquid to enable the refrigerant to expand and be used for expansion power generation. A heat exchange part is further arranged between the refrigerant circulation loop and the LNG conveying pipeline of the LNG receiving station and used for cooling the expanded refrigerant so that the refrigerant can be recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG receiving stations, and in particular to a safety and energy-saving system suitable for LNG receiving stations. Background Art

[0002] LNG (Liquefied Natural Gas) is an ultra-low temperature clean energy. LNG receiving stations use gasification technology to convert liquid into natural gas and then transport it to downstream users.

[0003] Research has found that the LNG gasification process can release more than 800kJ / kg of cold energy, but the current cold energy utilization rate is only 10%, resulting in huge cold energy waste. At the same time, there is also a large amount of carbon emissions during the LNG gasification process.

[0004] Therefore, it is necessary to develop energy-saving systems that can be applied to LNG receiving stations to reduce energy waste and reduce carbon emissions. Summary of the invention

[0005] The present invention provides a safe and energy-saving system suitable for LNG receiving stations. The system makes full use of LNG cold energy and waste heat from the back of photovoltaic panels, and adopts intermediate medium heat exchange expansion to generate electricity. It can provide power for production and life in the LNG receiving station, and can directly gasify LNG, thereby extending the life of photovoltaic panels, reducing the possibility of spontaneous combustion due to excessive backplane temperature, improving the utilization of LNG cold energy and photovoltaic power generation efficiency, solving the problem of energy waste, and reducing the production cost of the receiving station.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present application provides a safe and energy-saving system applicable to an LNG receiving station, comprising: a photovoltaic-thermal integrated system and a refrigerant expansion power generation system;

[0008] The photovoltaic-thermal integrated system comprises: a photovoltaic power generation device and a thermal storage liquid circulation loop; a heat exchange part is provided between the thermal storage liquid circulation loop and the photovoltaic power generation device, which is used to absorb the heat generated during the power generation process of the photovoltaic power generation device and heat the thermal storage liquid;

[0009] The refrigerant expansion power generation system has a refrigerant circulation loop, and a heat exchange part is also provided between the refrigerant circulation loop and the thermal storage liquid circulation loop to absorb the heat of the thermal storage liquid to expand the refrigerant for expansion power generation;

[0010] The refrigerant circulation loop also has a heat exchange portion between the LNG transmission pipeline of the LNG receiving station, which is used to cool the expanded refrigerant for circulating the refrigerant.

[0011] In one implementation, the photovoltaic power generation device includes a solar photovoltaic panel;

[0012] The heat exchange part between the photovoltaic power generation device and the thermal storage liquid circulation loop is located at the back plate of the solar photovoltaic panel.

[0013] In one implementation, the thermal storage liquid circulation loop has a plurality of continuous U-shaped pipes at the back plate of the solar photovoltaic panel, and the U-shaped pipes are clamped on the back plate by a clamp.

[0014] In one implementation, the thermal storage liquid circulation loop further includes a thermal storage tank, and an in-tank pump is provided in the thermal storage tank.

[0015] In one implementation, the thermal storage fluid is water.

[0016] In one implementation, the refrigerant circulation loop includes: a refrigerant cold storage tank, a refrigerant delivery pipeline, and an expansion generator.

[0017] In one implementation, the refrigerant delivery pipeline is led out from the refrigerant cold storage tank, and after passing through the heat exchange part with the heat storage liquid circulation loop, it is divided into two parallel first branches and second branches through a three-way valve, and the other ends of the first branch and the second branch are connected to the refrigerant cold storage tank.

[0018] In one implementation, the first branch has a first expansion generator; the second branch has a second expansion generator.

[0019] In one implementation, the first branch and the second branch each have an independent heat exchange portion with the LNG delivery pipeline.

[0020] In one implementation, one end of the LNG transmission pipeline is connected to the LNG receiving storage tank, and the other end outputs natural gas to the user end.

[0021] Compared with the prior art, the technical solution of the present invention, a safe and energy-saving system that comprehensively utilizes LNG cold energy and photovoltaic waste heat, can indirectly utilize the cold energy of LNG, absorb the waste heat from the back of the photovoltaic panel, and improve the safety of photovoltaic operation. At the same time, it realizes the cogeneration of cold and heat and the generation of clean electricity, which helps to reduce the production cost of the receiving station, promotes the application scenarios of the comprehensive utilization of photovoltaic waste heat and LNG cold energy, and improves the energy saving and safety efficiency of the LNG receiving station. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a process diagram of a safe and energy-saving system that comprehensively utilizes LNG cold energy and photovoltaic waste heat;

[0023] Figure 2 This is a schematic diagram of the structure of a photovoltaic panel cooling and heat exchange device;

[0024] Figure 3It is the power generation process and control diagram based on waste heat recovery from photovoltaic backplane and LNG cold energy;

[0025] Among them, 1-solar photovoltaic panel; 2-photovoltaic panel cooling and heat exchange device; 3-heat extraction device outlet control valve; 4-heat extraction device outlet pipeline; 5-hot water thermal storage tank; 6-hot water thermal storage tank internal pump; 7-hot water thermal storage tank outlet control valve; 8-hot water thermal storage tank outlet pipeline, hot water-refrigerant heat exchanger hot flow side inlet pipeline; 9-hot water-refrigerant heat exchanger; 10-hot water-refrigerant heat exchanger hot flow side outlet pipeline; 11-hot water-refrigerant heat exchanger cold flow side outlet control three-way valve; 12-second expander generator set inlet pipeline; 13-first expander generator set inlet pipeline; 14 first expander generator set; 15-first expander generator set outlet pipeline, first LNG-refrigerant heat exchanger hot flow side inlet pipeline; 16-first LNG-refrigerant Heat exchanger; 17-first LNG-refrigerant heat exchanger hot flow side outlet pipeline; 18-second expander generator set; 19-second LNG-refrigerant heat exchanger; 20-second LNG-refrigerant heat exchanger hot flow side inlet pipeline; 21-second LNG-refrigerant heat exchanger hot flow side outlet pipeline; 22-refrigerant cold storage tank; 23-refrigerant cold storage tank internal pump; 24-refrigerant cold storage tank outlet control valve; 25-first LNG-refrigerant heat exchanger cold flow side inlet pipeline; 26-first LNG-refrigerant heat exchanger cold flow side outlet pipeline, second LNG-refrigerant heat exchanger cold flow side inlet pipeline; 27-second LNG-refrigerant heat exchanger cold flow side outlet pipeline, NG external transmission pipeline; 31-photovoltaic panel cooling and heat exchange device fixture; 31-photovoltaic panel cooling and heat exchange device fixture. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0027] In view of the defects and problems of the prior art, the present application provides a safe and energy-saving system suitable for an LNG receiving station, including: a photovoltaic and thermal integrated system and a refrigerant expansion power generation system;

[0028] The photovoltaic-thermal integrated system comprises: a photovoltaic power generation device and a thermal storage liquid circulation loop; a heat exchange part is provided between the thermal storage liquid circulation loop and the photovoltaic power generation device, which is used to absorb the heat generated during the power generation process of the photovoltaic power generation device and heat the thermal storage liquid;

[0029] The refrigerant expansion power generation system has a refrigerant circulation loop, and a heat exchange part is also provided between the refrigerant circulation loop and the thermal storage liquid circulation loop to absorb the heat of the thermal storage liquid to expand the refrigerant for expansion power generation;

[0030] The refrigerant circulation loop also has a heat exchange portion between the LNG transmission pipeline of the LNG receiving station, which is used to cool the expanded refrigerant for circulating the refrigerant.

[0031] The above method is described below in a more detailed embodiment in conjunction with the accompanying drawings of the present application.

[0032] See also Figures 1 to 3 In a more detailed embodiment, a safe and energy-saving system for comprehensively utilizing LNG cold energy and photovoltaic waste heat is provided, including a photovoltaic-thermal integrated system and a refrigerant expansion power generation system.

[0033] The photovoltaic-thermal integrated system includes a solar photovoltaic power generation device, a photovoltaic panel cooling and heat exchange device, a hot water storage tank, water pipelines and control instrument valves.

[0034] The solar photovoltaic power generation device is a solar photovoltaic panel, which is used to convert solar energy into electrical energy and thermal energy;

[0035] The photovoltaic panel cooling heat exchange device is used to transfer the heat energy of the solar photovoltaic backplane to water to increase the temperature of the water. There are mounting clips on both sides of the heat exchange device to fix the heat exchange device on the solar panel. The main body of the heat exchange device is composed of a coil. A water inlet is provided on one side of the heat exchange device, and a water outlet is provided on the other side. The power generation efficiency of the solar photovoltaic panel is limited. Part of the solar energy is converted into backplane heat and dissipated. Normal temperature water enters the water inlet of the heat exchange device through a water pump, enters the coil, and flows through the photovoltaic backplane. The normal temperature water exchanges heat with the photovoltaic backplane, lowering the temperature of the photovoltaic backplane while increasing the water temperature in the pipe, avoiding the solar photovoltaic panel temperature from being too high, resulting in poor power generation efficiency, and at the same time avoiding the risk of photovoltaic spontaneous combustion caused by excessive temperature.

[0036] The hot water thermal storage tank is used to collect hot water that has absorbed the waste heat from the photovoltaic back panel. The inlet at the bottom of the tank is connected to the water outlet of the photovoltaic panel cooling and heat exchange device. The top of the tank is provided with a water outlet. There is a water pump in the tank for circulating hot water. A hot water pressure and temperature detection device is provided at the water outlet. The hot water thermal storage tank is provided with a U-shaped liquid level gauge.

[0037] The water pipeline is used for hot water circulation, connecting the outlet of the photovoltaic panel cooling heat exchange device and the inlet of the hot water heat storage tank, the outlet of the hot water heat storage tank and the inlet of the hot flow side of the hot water-refrigerant heat exchanger, and the outlet of the hot flow side of the hot water-refrigerant heat exchanger and the inlet of the photovoltaic cooling device.

[0038] The refrigerant expansion power generation system is connected to the LNG pipeline, and is used to gasify the refrigerant at the water-refrigerant heat exchange device, generate electricity from the refrigerant at the expander generator set, and exchange heat with LNG at the LNG-refrigerant heat exchange device to liquefy the refrigerant and return it to the cold storage tank.

[0039] The refrigerant expansion power generation system includes a refrigerant cold storage tank, a refrigerant circulation pump, a water-refrigerant heat exchange device, an expander, an LNG-refrigerant heat exchange device, an LNG pipeline, a refrigerant pipeline and control instrument valves.

[0040] The cold storage tank is used to store low-temperature liquid refrigerant, and contains a refrigerant pump inside. The bottom is connected to a refrigerant inlet pipe, and the top is connected to a refrigerant outlet pipe.

[0041] The refrigerant circulation pump is installed at the bottom of the refrigerant cold storage tank and is used to pressurize the liquid refrigerant and transport the refrigerant to the circulation pipeline.

[0042] The water-refrigerant heat exchange device is used for heat exchange between hot water and refrigerant, so that the refrigerant absorbs heat from the hot water and undergoes a gasification phase change. The water-refrigerant heat exchange device connects the refrigerant pipeline and the hot water pipeline.

[0043] The expander is connected to the outlet of the water-refrigerant heat exchange device and is used for expanding the vaporized refrigerant gas to generate electricity.

[0044] The LNG-refrigerant heat exchange device is connected to the outlet of the expander and is used for the gaseous refrigerant to absorb the internal heat of the LNG and exchange heat with the LNG, thereby reducing the temperature and causing liquefaction.

[0045] In an optional example, the refrigerant expansion power generation system includes a refrigerant cold storage tank (including an in-tank pump), two expander generator sets, two LNG-refrigerant heat exchangers, a refrigerant pipeline and an LNG pipeline.

[0046] The outlet of the refrigerant cold storage tank is split through the refrigerant pipeline and connected to the inlet of the first expander generator set and the outlet of the second expander generator set, the outlet of the first expander generator set is connected to the hot flow side inlet of the first LNG-refrigerant heat exchanger; the hot flow side outlet of the first LNG-refrigerant heat exchanger is connected to the inlet of the refrigerant cold storage tank; the hot flow side outlet of the second LNG-refrigerant heat exchanger is connected to the inlet of the refrigerant cold storage tank; the LNG from the receiving station flows through the LNG pipeline to the cold flow side inlet of the first LNG-refrigerant heat exchanger, and the cold flow side outlet of the first LNG-refrigerant heat exchanger is connected to the cold flow side inlet of the second LNG-refrigerant heat exchanger through the LNG pipeline.

[0047] Specific as Figure 1, a safe and energy-saving system, which uses flowing hot water to absorb the waste heat of the photovoltaic backplane, and then uses the hot water to heat the liquid low-temperature refrigerant, causing it to gasify and expand in volume, and generate electricity in the expansion unit. Low-temperature LNG is introduced, and the gaseous refrigerant in the heat exchanger undergoes two step heat exchanges to liquefy the refrigerant, realizing the recycling of the refrigerant.

[0048] The photovoltaic-thermal integrated system is connected to the refrigerant expansion power generation system, and is used to convert solar energy into electrical energy, and at the same time to absorb the waste heat of the photovoltaic panels, so that the photovoltaic panels are cooled and the circulating water is heated;

[0049] The refrigerant expansion power generation system is connected to the LNG pipeline, and is used to gasify the refrigerant at the water-refrigerant heat exchange device, generate electricity with the refrigerant at the expander generator set, and exchange heat with LNG at the LNG-refrigerant heat exchange device to liquefy the refrigerant and return it to the cold storage tank.

[0050] Photovoltaic panel cooling and heat exchange device as attached Figure 2 As shown, it is fixed on the photovoltaic backboard with a clamp, and water is used as the medium to extract heat. It enters the hot water storage tank through the control valve 3. The storage tank is equipped with a U-shaped liquid level gauge, pressure and temperature sensors. When the hot water tank is over-pressured, the PSV will work and burst to release the pressure. An in-tank pump is set at the bottom of the tank to pressurize the hot water, so that it enters the heat exchanger for contact heat exchange with the refrigerant, and ensures the circulation of the hot water in the photovoltaic and thermal integration system.

[0051] like Figure 3 The refrigerant expansion power generation system includes a first expander and a second expander, a first LNG-refrigerant heat exchanger and a second LNG-refrigerant heat exchanger, which are used to fully utilize the LNG cold energy.

[0052] The refrigerant cold storage tank is used to store low-temperature liquid refrigerant, and is equipped with a U-shaped liquid level gauge and a regulating control valve. When the liquid level is too high, it can be emptied. There is an in-tank pump at the bottom of the refrigerant cold storage tank, which is used to pressurize the liquid refrigerant so that it circulates in the refrigerant expansion power generation system. After being pressurized by the in-tank pump, the low-temperature refrigerant enters the 9-hot water-refrigerant heat exchanger to exchange heat with hot water to obtain a gaseous refrigerant. After passing through the three-way regulating valve 11, the first gaseous refrigerant enters the first expansion machine 14, and the second gaseous refrigerant enters the second expansion machine 18 to expand and generate electricity.

[0053] The low-temperature LNG from the storage tank of the LNG receiving station is transmitted to the first LNG-refrigerant heat exchanger through the 25 pipeline to exchange heat with the first gaseous refrigerant, so that it is cooled and liquefied, and then circulated back to the 23 refrigerant cold storage tank; then the LNG flowing out of the first LNG-refrigerant heat exchanger enters the second LNG-refrigerant heat exchanger to exchange heat with the second gaseous refrigerant, so that the refrigerant is cooled and liquefied, flows through the 21-second LNG-refrigerant heat exchanger hot flow side outlet pipeline, and circulates back to the 23 refrigerant cold storage tank;

[0054] The LNG from the receiving station enters the first LNG-refrigerant heat exchanger and the second LNG-refrigerant heat exchanger in turn, and after the gaseous refrigerant is liquefied, it is transported to the high-pressure export pump of the receiving station through the 27-receiving station NG export pipeline.

[0055] In summary, the present invention discloses a safe and energy-saving system that comprehensively utilizes LNG cold energy and photovoltaic waste heat, including a solar photovoltaic power generation device, a photovoltaic panel cooling and heat exchange device, a hot water heat storage tank, a refrigerant cold storage tank, a water-refrigerant heat exchange device, an expander generator set, an LNG-refrigerant heat exchange device, an LNG pipeline, a water pipeline and a refrigerant pipeline. By transforming the photovoltaic panel cooling and heat exchange device to the photovoltaic backboard, circulating water is used to absorb and store the waste heat of the photovoltaic backboard. At the same time, the LNG cold energy resources of the receiving station are utilized, and the refrigerant is used to absorb hot water for heat storage, expand and generate electricity, and then exchange cold with LNG for liquefaction, and pressurize and circulate. This safe and energy-saving system that comprehensively utilizes LNG cold energy and photovoltaic waste heat realizes the absorption of photovoltaic backboard waste heat, reduces the temperature of the photovoltaic panel, and avoids the risk of spontaneous combustion. At the same time, LNG cold energy is used to realize the joint production and supply of cold, heat and electricity, thereby improving the utilization efficiency of LNG cold energy, reducing the risk of photovoltaic operation, and achieving the purpose of safety and energy saving.

[0056] In the several embodiments provided by the present invention, it should be understood that the disclosed method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the above units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0057] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A safety and energy-saving system suitable for an LNG receiving station, characterized in that: include: Photovoltaic and thermal integrated system and refrigerant expansion power generation system; The photovoltaic-thermal integrated system comprises: a photovoltaic power generation device and a thermal storage liquid circulation loop; a heat exchange part is provided between the thermal storage liquid circulation loop and the photovoltaic power generation device, which is used to absorb the heat generated during the power generation process of the photovoltaic power generation device and heat the thermal storage liquid; The refrigerant expansion power generation system has a refrigerant circulation loop, and a heat exchange part is also provided between the refrigerant circulation loop and the thermal storage liquid circulation loop to absorb the heat of the thermal storage liquid to expand the refrigerant for expansion power generation; The refrigerant circulation loop also has a heat exchange portion between the LNG transmission pipeline of the LNG receiving station, which is used to cool the expanded refrigerant for circulating the refrigerant.

2. The safety and energy-saving system applicable to LNG receiving stations according to claim 1 is characterized in that: The photovoltaic power generation device includes a solar photovoltaic panel; The heat exchange part between the photovoltaic power generation device and the thermal storage liquid circulation loop is located at the back plate of the solar photovoltaic panel.

3. The safety and energy-saving system applicable to LNG receiving stations according to claim 2 is characterized in that: The thermal storage liquid circulation loop has a plurality of continuous U-shaped pipes at the back plate of the solar photovoltaic panel, and the U-shaped pipes are clamped on the back plate by a clamp.

4. The safety and energy-saving system applicable to LNG receiving stations according to claim 3 is characterized in that: The thermal storage liquid circulation loop also includes a thermal storage tank, and an in-tank pump is arranged in the thermal storage tank.

5. The safety and energy-saving system applicable to LNG receiving stations according to claim 4 is characterized in that: The thermal storage fluid is water.

6. The safety and energy-saving system applicable to LNG receiving stations according to claim 1 is characterized in that: The refrigerant circulation loop includes: a refrigerant cold storage tank, a refrigerant delivery pipeline and an expansion generator.

7. The safety and energy-saving system applicable to LNG receiving stations according to claim 6 is characterized in that: The refrigerant delivery pipeline is led out from the refrigerant cold storage tank, and after passing through the heat exchange part with the heat storage liquid circulation loop, it is divided into two parallel first branches and second branches through a three-way valve. The other ends of the first branch and the second branch are connected to the refrigerant cold storage tank.

8. The safety and energy-saving system applicable to LNG receiving stations according to claim 7 is characterized in that: The first branch has a first expansion generator; the second branch has a second expansion generator.

9. The safety and energy-saving system applicable to LNG receiving stations according to claim 8 is characterized in that: The first branch and the second branch each have an independent heat exchange portion with the LNG delivery pipeline.

10. The safety and energy-saving system applicable to LNG receiving stations according to claim 1, characterized in that: One end of the LNG transmission pipeline is connected to the LNG receiving tank, and the other end outputs natural gas to the user end.

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