LNG (Liquefied Natural Gas) phase change energy storage skid-mounted gasifier and operation method thereof

Abstract

The invention discloses an LNG phase change energy storage skid-mounted gasifier and an operation method thereof, and relates to the technical field of LNG cold energy utilization, the LNG phase change energy storage skid-mounted gasifier comprises an LNG gasification module, a refrigerant liquefaction module, an NG reheating module, a phase change energy storage module and a skid-mounted integrated base; lNG is sent into the LNG gasification module and enters a pipe network after being gasified through circulating heat exchange of an intermediate medium, the phase change energy storage module stores and releases cold energy according to output load fluctuation, and a refrigerant can enter the downstream to enter the LNG cold energy utilization device for cold supply and returns to a gasifier for circulating heat exchange after being reheated through the industrial waste heat recovery device; according to the gasifier, LNG gasification is efficiently achieved, meanwhile, cold energy can be recycled and output for use, and waste of cold energy resources is avoided; cold energy dynamic adjustment is achieved through the phase change energy storage module, and output demand fluctuation is flexibly adapted; cold energy and waste heat are cooperatively utilized, and the comprehensive utilization efficiency of energy is high; the skid-mounted integrated design supports rapid deployment and expansion, and the multiple parallel devices can flexibly adapt to the capacity requirements of different scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of LNG cold energy utilization, and specifically to an LNG phase change energy storage skid-mounted gasifier and an operation method thereof, which can be applied to scenarios such as small and medium-sized LNG receiving stations, satellite stations, and gas filling stations. Background Art

[0002] Liquefied Natural Gas (LNG) is a -162°C cryogenic liquid hydrocarbon mixture formed by a multi-stage compression refrigeration process after gaseous natural gas has been pre-treated by dehydration and desulfurization. Before being supplied to downstream users, LNG needs to be heated to above 0°C through a gasification process before it can be input into the natural gas pipeline network. A large amount of cold energy will be generated during the LNG gasification process (the gasification process releases approximately 830kJ / kg of cold energy). If this cold energy can be fully utilized, it will play an important role in the implementation of relevant policies for my country's "dual carbon" goals, energy structure adjustment, energy storage peak regulation, and cold industry upgrading. Therefore, research on LNG cold energy recovery and reuse technology has become an important means to support the sustainable and healthy development of my country's LNG industry.

[0003] Currently, LNG gasification technology primarily utilizes fixed equipment such as open-frame, intermediate medium, and submerged combustion types. These are designed primarily for large-scale continuous gasification and are widely used in large LNG receiving stations. However, for small and medium-sized LNG receiving stations, satellite stations, and gas stations, fixed equipment is limited by high initial investment costs, large floor space, and long deployment cycles, making it difficult to meet the requirements for cost-effective and flexible deployment. Therefore, to address small and medium-sized gasification needs, the industry has proposed a skid-mounted gasifier technology solution. This modular integration enables rapid deployment, supports road transport, and allows for quick installation. It is particularly suitable for land-constrained suburban gas stations or emergency peak-shaving facilities.

[0004] Existing skid-mounted vaporizers mainly follow the technical route of traditional air-temperature or water-bath vaporizers. Chinese patent application CN116877916A discloses a natural gas vaporization skid with a water-bath vaporizer as the main body, which reduces the gasification energy consumption by combining a solar heating system. Chinese patent application CN109780433A discloses an enhanced reheating natural gas gasification skid with an air-temperature vaporizer as the main body, which improves the gasification efficiency through structural modification. The skid-mounted vaporizers in the above technical solutions all have the single design goal of efficiently completing LNG gasification, and their functional design has significant limitations: during the LNG gasification process, neither a cold storage structure is considered to store the released high-grade cold energy, nor is a cold energy transmission channel considered to realize the external transmission and utilization of cold energy. This one-way energy conversion design leads to a serious waste of cold energy resources and has systemic defects in energy utilization.

[0005] Furthermore, during the LNG gasification and export process, the uncertainty of downstream user demand leads to frequent fluctuations in export load, resulting in significant peak-to-valley variations in LNG cold energy output. This mismatch between supply and demand results in inefficient LNG cold energy utilization and leads to stability issues such as fluctuating operating parameters and frequent equipment startups and shutdowns in cold energy utilization equipment. Technical measures are urgently needed to achieve a dynamic balance between cold energy supply and demand, thereby improving cold energy utilization efficiency and ensuring stable equipment operation. Summary of the Invention

[0006] The purpose of the present invention is to overcome at least one of the shortcomings and deficiencies of the prior art and to provide an LNG phase change energy storage skid-mounted vaporizer and its operating method. The vaporizer is based on the structure and working principle of an integral intermediate medium vaporizer. A cold energy transmission channel between LNG and the external system is established through an intermediate medium, and cold energy is exported and utilized by the refrigerant. A phase change energy storage module is set at the refrigerant export end to form a dynamic adjustment mechanism of "cold energy capture-phase change energy storage-external utilization". When the system has an excess supply of cold energy, the phase change material absorbs the excess cold energy to complete solidification and energy storage; when the external demand for cold energy increases, the phase change material melts and releases energy, achieving a temporal and spatial matching of cold energy supply and demand, and improving the efficiency of cold energy utilization. Before returning to the vaporizer, the refrigerant can flow through an industrial waste heat recovery device to convert waste heat into power for LNG gasification, forming a closed-loop system for the coordinated utilization of cold and hot energy, further improving the comprehensive efficiency of energy utilization.

[0007] In order to achieve the purpose of the present invention, the present invention provides an LNG phase change energy storage skid-mounted vaporizer, comprising a skid-mounted integrated base and an LNG vaporization module, a refrigerant liquefaction module, an NG reheating module and a phase change energy storage module arranged on the skid-mounted integrated base;

[0008] The LNG gasification module and the refrigerant liquefaction module are connected through the E1 / E2 shell side. The E1 / E2 shell side is filled with refrigerant as an intermediate medium. The LNG gasification module is provided with spiral finned tubes. The refrigerant liquefaction module is provided with a refrigerant liquefaction tube bundle, and the spiral finned tubes are located above the refrigerant liquefaction tube bundle. The LNG gasification module is provided with an LNG inlet, a low-temperature NG outlet and an intermediate medium inlet. The LNG inlet and the low-temperature NG outlet are respectively connected to both ends of the spiral finned tubes.

[0009] The NG reheating module is provided with a low-temperature NG inlet, an NG outlet, a gaseous refrigerant inlet and an NG reheating tube bundle. The low-temperature NG inlet is connected to the low-temperature NG outlet. The two ends of the NG reheating tube bundle are respectively connected to the low-temperature NG inlet and the NG outlet. The two ends of the shell side of the NG reheating module are respectively connected to the gaseous refrigerant inlet and the refrigerant liquefaction tube bundle.

[0010] The phase change energy storage module is connected to the LNG gasification module and the refrigerant liquefaction module through a fixed end plate. The phase change energy storage module is provided with a bracket and a spiral coil, and the spiral coil is connected to the refrigerant liquefaction tube bundle and the liquid refrigerant outlet;

[0011] A spare refrigerant outlet is provided between the phase change energy storage module and the refrigerant liquefaction module, and the spare refrigerant outlet is communicated with the refrigerant liquefaction tube bundle.

[0012] Specifically, the skid-mounted integrated base includes a shock-absorbing pad, a skid-mounted plate and an integrated plate. The skid-mounted plate and the integrated plate are arranged opposite to each other, the shock-absorbing pad is located between the skid-mounted plate and the integrated plate, and the LNG gasification module, the refrigerant liquefaction module, the NG reheating module and the phase change energy storage module are arranged on the integrated plate.

[0013] Specifically, the shell side of the NG reheating module is further provided with baffles, which are installed in a vertically staggered manner on the shell side.

[0014] Specifically, the LNG gasification module is provided with a safety valve group and a pressure indicator for gas overpressure protection and pressure monitoring of the E1 / E2 shell side.

[0015] Specifically, the intermediate medium is a low-temperature working medium, the standard boiling point of which is ≤-70°C, and the latent heat of phase change in the temperature range of -150°C to -50°C is ≥180 kJ / kg.

[0016] Preferably, the cryogenic working medium is selected from at least one of alkanes, fluorocarbons or liquid carbon dioxide, and circulates between the LNG gasification module and the refrigerant liquefaction module to transfer cold energy.

[0017] Specifically, the refrigerant is a low-temperature working fluid, whose standard boiling point is ≤-50°C, and whose phase change latent heat in the temperature range of -100°C to 0°C is ≥200kJ / kg.

[0018] Preferably, the cryogenic working fluid is selected from at least one of fluorocarbons or liquid CO2, and is used to carry cold energy to a downstream LNG cold energy utilization device for providing cold energy.

[0019] Specifically, the phase change energy storage module includes a shell, a multi-layer bracket is arranged in the shell, a packaging tube is arranged on the bracket, microcapsules are encapsulated in the packaging tube, and phase change material is arranged in the microcapsule; and a spiral coil is arranged between adjacent brackets, and a refrigerant circulates in the spiral coil.

[0020] Preferably, the brackets are arranged in layers, and their side walls are provided with an array of insertion holes for fixing the packaging tubes. The gaps between the outer walls of the packaging tube group and the insertion holes are filled with thermal grease, and microcapsules are encapsulated inside.

[0021] Specifically, the spiral coil is arranged between adjacent bracket components, and refrigerant flows through the tube, forming a heat exchange and energy storage network of the phase change energy storage module with the packaged tube group.

[0022] Specifically, the shell of the microcapsule is made of at least one of high-low temperature resistant polymer materials such as polyamide, polyurethane, polyurea and polyester, to ensure that the phase change material does not leak during the energy storage and release process.

[0023] Specifically, the phase change material is an organic compound with a solid-liquid phase change temperature of -50°C to 0°C, and its phase change latent heat is greater than 150 kJ / kg.

[0024] Preferably, the organic compound is selected from at least one of alkanes, alcohols and binary mixtures thereof.

[0025] Specifically, the phase change energy storage module is connected to the downstream LNG cold energy utilization device, which includes a refrigerant distribution, circulation and recovery unit, which is configured to output cold energy to the cold energy utilization device at a cold temperature position.

[0026] Preferably, the cold energy utilization device includes but is not limited to any one of a low-temperature cold storage, a vacuum freeze dryer or an ice maker, and the cold temperature range of the cold energy utilization device is -50°C to -10°C.

[0027] Specifically, the LNG cold energy utilization device is connected to an industrial waste heat recovery device, which is in turn connected to an LNG reheating module. The industrial waste heat recovery device includes a waste heat exchanger and a heat medium circulation pump. The shell side of the waste heat exchanger is connected to an external industrial heat source pipeline, while the tube side circulates refrigerant. The heat medium circulation pump drives the heat medium and refrigerant to exchange heat.

[0028] Specifically, the LNG phase change energy storage skid-mounted gasifiers can be arranged in parallel.

[0029] The present invention provides an operating method for an LNG phase-change energy storage skid-mounted gasifier, comprising the following steps:

[0030] S1: LNG is fed into the LNG gasification module, where it exchanges heat with the gaseous intermediate medium in the E1 / E2 shell side. After initial gasification, it enters the NG reheating module, where it undergoes countercurrent reheating with the gaseous refrigerant to complete the gasification process. It can then enter the downstream natural gas pipeline network.

[0031] S2: After exchanging heat with the low-temperature LNG, the gaseous intermediate medium liquefies and falls to the refrigerant liquefaction module, where it exchanges heat with the gaseous refrigerant. The gaseous intermediate medium then vaporizes and rises again, completing the intermediate medium circulation heat exchange.

[0032] S3. When the fluctuation rate of the LNG flow entering the LNG gasification module reaches a preset value, it is considered that the LNG flow has entered a peak or valley stage. When the input LNG flow rises to near the peak value, the gaseous refrigerant exchanges heat with the liquid intermediate medium and cools down to liquefaction before entering the phase change energy storage module, where the cold energy is stored. When the input LNG flow drops to near the valley value, the cold energy in the phase change energy storage module is released to the liquid refrigerant to supplement the cooling, thereby maintaining the refrigerant's external transmission temperature and achieving energy storage peak regulation.

[0033] S4. After the liquid refrigerant achieves energy storage and peak regulation, it is sent to the downstream for cooling and then reheated to complete the refrigerant circulation and heat exchange.

[0034] Furthermore, in step S3, when the LNG load fluctuation rate is ≤5% and lasts for 2 hours or more, the liquid refrigerant outlet is closed and the backup liquid refrigerant outlet is activated to reduce the frequency of phase change material use and increase the material life.

[0035] Compared with the prior art, the present invention has the following advantages and effects:

[0036] 1. The skid-mounted vaporizer of the present invention can not only efficiently realize LNG gasification, but also recover the cold energy generated by gasification and transmit it for external utilization, effectively avoiding the direct waste of cold energy resources in scenarios such as small and medium-sized LNG receiving stations, satellite stations and gas stations, thereby improving the efficiency of cold energy utilization.

[0037] 2. The skid-mounted gasifier of the present invention couples LNG gasification with phase-change energy storage, and a phase-change energy storage module is provided in the system to realize a dynamic regulation mechanism of cold energy. It can store excess cold energy when there is excess cold energy, and release cold energy when external cooling demand increases. It can flexibly adapt to fluctuations in the demand for external cooling energy, and the system has strong dynamic response capabilities and high supply-demand matching efficiency.

[0038] 3. In the skid-mounted vaporizer of the present invention, the refrigerant flows through the industrial waste heat recovery device before returning to the vaporizer, converting industrial waste heat into LNG gasification power, realizing the simultaneous utilization of cold energy and waste heat, and having high comprehensive energy utilization efficiency.

[0039] 4. The skid-mounted gasifier of this invention utilizes an integrated skid-mounted design, enabling integrated road transport and rapid on-site deployment. This eliminates the need for complex on-site assembly, significantly shortening the project installation cycle. Furthermore, the gasifier is scalable. By operating multiple skid-mounted gasifiers in parallel, the gas supply scale can be flexibly adjusted based on actual gas demand, meeting gasification capacity requirements in various scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the overall structure of the LNG phase change energy storage skid-mounted gasifier in an embodiment of the present invention;

[0041] Figure 2 This is a schematic structural diagram of a phase change energy storage module according to an embodiment of the present invention;

[0042] Figure 3 Schematic diagram of the packaging structure of the phase change material in an embodiment of the present invention;

[0043] Figure 4 Schematic diagram of the operating method of the skid-mounted gasifier in an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the parallel operation of gasifiers according to an embodiment of the present invention.

[0045] In the figure: 1. Gaseous refrigerant inlet; 2. NG outlet; 3. Baffle; 4. Shell side; 5. Low-temperature NG inlet; 6. Fixed end plate; 7. Low-temperature NG outlet; 8. Safety valve group; 9. Pressure indicator; 10. E1 / E2 shell side; 11. Spiral finned tube; 12. LNG inlet; 13. Bracket; 14. Spiral coil; 15. Liquid refrigerant outlet; 16. Standby refrigerant outlet; 17. Intermediate medium inlet; 18. Shock-absorbing pad; 19. Refrigerant liquefaction tube bundle; 20. NG reheating tube bundle; 21. Skid plate; 22. Integrated board; 23. Cryogenic centrifugal pump; 24. LNG cold energy utilization device; 25. Industrial waste heat recovery device; 26. Encapsulation tube; 27. Microcapsule; 28. Phase change material; E1. LNG gasification module; E2. Refrigerant liquefaction module; E3. NG reheating module; E4. Phase change energy storage module DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, upper end, lower end, top, bottom...) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In the present invention, unless otherwise specified or limited, the term "connection" should be understood in a broad sense. For example, "connection" can mean fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two elements, or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0049] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include at least one such feature. Furthermore, the technical solutions of various embodiments may be combined with each other, but only on the basis that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions contradicts or cannot be implemented, it shall be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this disclosure.

[0050] like Figure 1 As shown, an embodiment of the present invention provides an LNG phase change energy storage skid-mounted vaporizer, comprising an LNG vaporization module E1, a refrigerant liquefaction module E2, an NG reheating module E3, a phase change energy storage module E4 and a skid-mounted integrated base.

[0051] The LNG gasification module E1 and the refrigerant liquefaction module E2 share a shell, which is defined as the E1 / E2 shell. The LNG gasification module E1 is arranged at the upper part of the E1 / E2 shell, and the refrigerant liquefaction module E2 is arranged at the lower part of the E1 / E2 shell. The LNG gasification module E1 and the refrigerant liquefaction module E2 are connected through the E1 / E2 shell side 10. The E1 / E2 shell side 10 can be loaded with refrigerant as an intermediate medium. A spiral finned tube 11 is arranged at the upper part of the E1 / E2 shell, and a refrigerant liquefaction tube bundle 19 is arranged at the lower part of the E1 / E2 shell. The spiral finned tube 11 is located above the refrigerant liquefaction tube bundle 19. An LNG inlet 12 and a low-temperature NG outlet 7 are arranged on the E1 / E2 shell at a position corresponding to the LNG gasification module E1. An intermediate medium inlet 17 is provided at the bottom of the E1 / E2 shell. The LNG inlet 12 and the low-temperature NG outlet 7 are respectively connected to the two ends of the spiral finned tube 11. The phase change energy storage module E4 and the NG reheating module E3 are respectively arranged on both sides of the E1 / E2 shell. A backup refrigerant outlet 16 is provided between the refrigerant liquefaction module E2 and the phase change energy storage module E4, so that the liquid refrigerant can choose to enter the phase change energy storage module E4 according to the fluctuation of the LNG flow, or choose to directly enter the downstream through the backup refrigerant outlet 16. The refrigerant liquefaction tube bundle 19 is connected to the backup refrigerant outlet 16.

[0052] The NG reheating module E3 is connected to the LNG gasification module E1 and the refrigerant liquefaction module E2 via fixed end plates 6. The shell of the NG reheating module E3 is provided with a low-temperature NG inlet 5, an NG outlet 2, and a gaseous refrigerant inlet 1. A deflector 3 is provided within the shell side 4 of the NG reheating module E3. The shell side 4 also includes an NG reheating tube bundle 20. The two ends of the NG reheating tube bundle 20 are connected to the low-temperature NG inlet 5 and the NG outlet 2, respectively. The two ends of the shell side 4 are connected to the gaseous refrigerant inlet 1 and the refrigerant liquefaction tube bundle 19, respectively. The low-temperature NG inlet 5 is connected to the low-temperature NG outlet 7. In one embodiment of the present invention, the deflector 3 is installed within the shell side 4 in a vertically staggered manner.

[0053] The phase-change energy storage module E4 is connected to the LNG vaporization module E1 and the refrigerant liquefaction module E2 via a fixed end plate 6. A bracket 13 and a spiral coil 14 are located within the housing of the phase-change energy storage module E4. The spiral coil 14 communicates with the refrigerant liquefaction tube bundle 19 and the liquid refrigerant outlet 15. A packaging tube 26 is located within the bracket 13. Microcapsules 27 are encapsulated within the packaging tube 26, and phase-change material 28 is contained within the microcapsules 27. Both the liquid refrigerant outlet 15 and the backup refrigerant outlet 16 are connected to the LNG cold energy utilization device 24 via a cryogenic centrifugal pump 23.

[0054] The spiral finned tube 11 and the spiral coil 14 are arranged in a spiral manner. Through the spiral arrangement, the internal space of the equipment can be maximized, the heat exchange area of ​​the fluid can be effectively increased, and the heat exchange efficiency can be improved.

[0055] A multi-layer bracket 13 is provided in the shell of the phase change energy storage module E4, and a spiral coil 14 is provided between any two adjacent brackets 13. The input end of each spiral coil 14 is connected to the outlet of the refrigerant liquefaction tube bundle 19, and the output end is connected to the liquid refrigerant outlet 15.

[0056] In one embodiment of the present invention, Figure 2 As shown, the brackets 13 are arranged in layers, and their side walls are provided with an array of holes for fixing the packaging tubes 26. The gap between the outer wall of the packaging tube group and the holes is filled with thermal grease. The interior of the packaging tube 26 is encapsulated with microcapsules 27, and the microcapsules 27 are provided with phase change material 28. Spiral coils 14 are provided between adjacent brackets 13. Refrigerant flows through the spiral coils 14, forming a heat exchange and energy storage network of the phase change energy storage module with the packaging tube group 26.

[0057] In one embodiment of the present invention, Figure 3 As shown, the shell of the microcapsule 27 is made of at least one of high-low temperature resistant polymer materials such as polyamide, polyurethane, polyurea and polyester, to ensure that the phase change material does not leak during the energy storage and release process.

[0058] The skid-mounted integrated base includes a skid-mounted plate 21 , a shock-absorbing pad 18 and an integrated plate 22 . The skid-mounted plate 21 and the integrated plate 22 are arranged opposite to each other, and the shock-absorbing pad 18 is located above the skid-mounted plate 21 and below the integrated plate 22 .

[0059] In one embodiment of the present invention, a safety valve group 8 and a pressure indicator 9 are provided on the E1 / E2 shell for gas overpressure protection and pressure monitoring of the E1 / E2 shell side.

[0060] like Figure 4 As shown, the LNG cold energy utilization device 24 includes a refrigerant distribution, circulation and recovery unit, which is configured to output cold energy to a cold energy utilization device at a shallow cold temperature position.

[0061] LNG is vaporized through intermediate medium circulation heat exchange and then enters the pipeline network. The phase change energy storage module stores and releases cold energy according to the fluctuation of external load. The refrigerant enters the downstream LNG cold energy utilization device 24 for cooling, and then returns to the vaporizer for circulation heat exchange after being reheated by the industrial waste heat recovery device 25.

[0062] In one embodiment of the present invention, the LNG cold energy utilization device 24 includes but is not limited to any one of a low-temperature cold storage, a vacuum freeze dryer or an ice maker, and the cold temperature range of the LNG cold energy utilization device 24 is -50°C to -10°C.

[0063] In one embodiment of the present invention, the industrial waste heat recovery device 25 includes a waste heat exchanger and a heat medium circulation pump. The shell side of the waste heat exchanger is connected to an external industrial heat source pipeline, and the refrigerant flows through the tube side; the heat medium circulation pump drives the heat medium (such as hot water, hot air, steam, etc.) to exchange heat with the refrigerant.

[0064] In one embodiment of the present invention, the shock-absorbing pad layer 18 is preferably made of rubber isolation material, which can reduce the vibration impact amplitude of the skid-mounted gasifier during transportation by 60%-70%, and at the same time reduce the noise generated by the gasifier during operation from 85-90 decibels to 65-70 decibels, significantly improving the equipment transportation reliability and operating environment comfort.

[0065] In one embodiment of the present invention, the intermediate medium is preferably ethane, which has a boiling point of -88.6°C at normal pressure, is suitable for the LNG gasification temperature zone, has a large latent heat of phase change, and can utilize the density difference between the gas and liquid phases and the action of gravity to achieve natural circulation flow without the assistance of a mechanical pump.

[0066] In one embodiment of the present invention, the safety valve group 8 is preferably a low-temperature safety valve with a set trip pressure of 0.63 MPa, which is 115% of the saturated vapor pressure of ethane at -50°C, 0.55 MPa. When overpressure is detected in the E1 / E2 shell side 10 and the duration is greater than 5s, the low-temperature safety valve is forced to open to relieve pressure, and the pressure indicator 9 simultaneously gives an audible and visual alarm. After the pressure is relieved, when the pressure drops to ≤0.4 MPa, the valve automatically resets.

[0067] In one embodiment of the present invention, the gaseous refrigerant inlet 1 is connected to the industrial waste heat recovery device 25 .

[0068] In one embodiment of the present invention, the refrigerant is preferably CO2. The latent heat of phase change of CO2 in the subcritical state is large, and it can efficiently transfer the cold energy of LNG at medium and low temperatures. Its non-flammable and non-toxic properties can reduce the safety risk of intermediate heat exchange.

[0069] In one embodiment of the present invention, the thermal grease is preferably a high-purity nano-scale filler product with a thermal conductivity coefficient of ≥3.5W / (m·K), which can control the interface temperature difference between the packaging tube 26 and the bracket 13 to within 2°C, effectively avoiding the performance degradation of the phase change material caused by uneven heat exchange.

[0070] In one embodiment of the present invention, phase change material 28 is preferably a binary mixture of n-decane and n-dodecane. This mixture is chemically stable, exhibits no supercooling, and has a long cycle life, making it suitable for long-term energy storage. When the mass fraction of n-decane in the n-decane-n-dodecane system is 77.3%, the lowest eutectic point is -33.4°C, and the latent heat of phase change is 194.1 kJ / kg, precisely matching the needs of LNG cold energy recovery and export.

[0071] In one embodiment of the present invention, the shell of the microcapsule 27 is preferably made of polyurea material. Polyurea has excellent mechanical strength, chemical stability and corrosion resistance, and can effectively block the volatilization and leakage of n-decane-n-dodecane. Its good flexibility and interfacial adhesion can adapt to the volume change of the phase change material. At the same time, it has low permeability and temperature resistance, and is suitable as a packaging shell material.

[0072] In one embodiment of the present invention, a method for operating an LNG phase change energy storage skid-mounted gasifier is provided, which can be specifically implemented by the following steps:

[0073] S1, LNG is pumped through the tank at 20000Nm 3 / h, -155°C, 6.0MPa state continuously enters the LNG gasification module E1 through the LNG inlet 12, exchanges heat with 33500kg / h, -50°C, 0.4MPa gaseous ethane in the E1 / E2 shell side 10 to complete preliminary gasification. After the temperature rises to -58°C, it enters the NG reheating module E2 and undergoes countercurrent reheating with 26000kg / h, 50°C, 1.3MPa gaseous CO2 from the industrial waste heat recovery device 25 to complete the gasification process. The temperature rises to about 5°C, and then passes through the pressure regulating and metering device to enter the downstream natural gas pipeline network;

[0074] After heat exchange with low-temperature LNG, the gaseous ethane at S2, at -50°C and 0.4MPa, is cooled to -60°C and liquefied and falls to the refrigerant liquefaction module E2, where it exchanges heat with the gaseous CO2 at -32°C and 1.3MPa, and is heated to -50°C again and vaporized and rises, completing the intermediate medium circulation heat exchange.

[0075] S3, when the LNG input flow reaches the upper limit preset value, such as 21000Nm 3 / h, that is, 105% of the average input flow rate, it is considered that the LNG input load has risen to the vicinity of the peak value, and the -32℃, 1.3MPa gaseous CO2 and -60℃, 0.4MPa liquid ethane are heat exchanged and cooled to -48℃ and liquefied before entering the phase change energy storage module E4. The cold energy is stored in the phase change material 28. The temperature range of the phase change energy storage module E4 is -48~-40℃. When the LNG input flow rate reaches the lower limit preset value, such as 19000Nm 3 / h, that is, 95% of the average input flow rate, the LNG input load is considered to have dropped to near the valley value, and 28% of the cold energy in the phase change material is released to the liquid CO2 to supplement the cooling, maintaining the external transmission temperature of the refrigerant liquid CO2 at -40℃ and 1.3Mpa, realizing energy storage peak regulation;

[0076] When the fluctuation rate of LNG flow is ≥5%, it is considered that the LNG flow has entered a peak or valley stage. The LNG gasification module input flow rate of S1 is 20000Nm 3 / h is the standard input flow rate of the equipment. When the input flow rate is 21000Nm 3 / h, (21000-20000) / 20000*100%=5%. When the input flow is 19000Nm 3 / h, (19000-20000) / 20000*100%=-5%, so the fluctuation rate of LNG flow is ≤5%. In the embodiment of the present invention, the normal fluctuation range of the equipment input flow is 19000~21000Nm 3 / h.

[0077] After S4 and liquid CO2 achieve peak energy storage and shaving, the refrigerant CO2 in phase-change energy storage module E4 is delivered to the downstream LNG cold energy ice-making device 24 via a cryogenic centrifugal pump 23 for cooling. The CO2 refrigerant's external cooling capacity is approximately 2500kW, with an ice-making capacity of approximately 400t / h and a cold energy utilization efficiency of approximately 87%. The refrigerant then enters the industrial waste heat recovery device 25 for reheating, recovering waste heat from the industrial circulating water, with a recovery capacity of approximately 480kW, completing the refrigerant heat cycle.

[0078] In the embodiment of the present invention, in step S3, when the LNG input flow rate is between 19000 and 21000 Nm 3 / h and lasts for 2 hours or more, the liquid refrigerant outlet 15 is closed and the backup refrigerant outlet 16 is activated. The energy storage cycle frequency of the phase change material 28 is reduced to 30-40% of the normal mode, and the latent heat decay rate is improved from 10-12% to 5-7%, which can significantly extend the service life of the phase change material.

[0079] like Figure 5 As shown, in one embodiment of the present invention, the maximum gasification capacity of a single gasifier is preferably 20000Nm 3 / h, for small LNG receiving stations, the gasification scale range is about 30,000 to 60,000 Nm 3 In application scenarios with large gasification scale requirements such as 1000 kW / h, a parallel operation solution can be adopted: three gasifiers of the same model are horizontally connected in parallel through a standard flange interface with a nominal diameter of DN300, and the number of starts and stops is adjusted to adapt to specific changes in gas demand.

[0080] When the gasification scale requirement is 54000Nm 3 / h, the LNG pumped from the storage tank is evenly distributed through the main pipeline at a speed of 18000Nm 3 / h of gaseous CO2 is delivered simultaneously to three parallel gasifiers. Similarly, 23,400 kg / h of gaseous CO2 from industrial waste heat recovery unit 25 is evenly distributed through the main pipeline and delivered simultaneously to the three parallel gasifiers at a flow rate of 7,800 kg / h. The three parallel gasifiers simultaneously perform LNG gasification, cold energy export utilization, and phase change energy storage. The gasified LNG is then fed into the gas gathering network for unified export, while the liquid CO2, having captured cold energy, is fed into the refrigerant main for delivery to downstream users, rapidly expanding the scale of gasification and cold energy export.

[0081] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An LNG phase change energy storage skid-mounted gasifier, characterized in that: It includes a skid-mounted integrated base and an LNG gasification module, a refrigerant liquefaction module, an NG reheating module and a phase change energy storage module arranged on the skid-mounted integrated base; The LNG gasification module and the refrigerant liquefaction module are connected through the E1 / E2 shell side, the E1 / E2 shell side is filled with refrigerant as an intermediate medium, the LNG gasification module is provided with a spiral finned tube (11), the refrigerant liquefaction module is provided with a refrigerant liquefaction tube bundle (19), and the spiral finned tube (11) is located above the refrigerant liquefaction tube bundle (19), the LNG gasification module is provided with an LNG inlet (12), a low-temperature NG outlet (7) and an intermediate medium inlet (17), and the LNG inlet (12) and the low-temperature NG outlet (7) are respectively connected to both ends of the spiral finned tube (11); The NG reheating module is provided with a low-temperature NG inlet (5), an NG outlet (2), a gaseous refrigerant inlet (1) and an NG reheating tube bundle (20); the low-temperature NG inlet (5) and the low-temperature NG outlet (7) are connected; the two ends of the NG reheating tube bundle (20) are respectively connected to the low-temperature NG inlet (5) and the NG outlet (2); the two ends of the shell side (4) of the NG reheating module are respectively connected to the gaseous refrigerant inlet (1) and the refrigerant liquefaction tube bundle (19); The phase change energy storage module is connected to the LNG gasification module and the refrigerant liquefaction module via a fixed end plate (6); the phase change energy storage module is provided with a bracket (13) and a spiral coil (14); the spiral coil (14) is connected to the refrigerant liquefaction tube bundle (19) and the liquid refrigerant outlet (15); A standby refrigerant outlet (16) is provided between the phase-change energy storage module and the refrigerant liquefaction module, and the standby refrigerant outlet (16) is communicated with the refrigerant liquefaction tube bundle (19).

2. The LNG phase change energy storage skid-mounted gasifier according to claim 1, characterized in that: The skid-mounted integrated base comprises a shock-absorbing pad layer (18), a skid-mounted plate (21) and an integrated plate (22); the skid-mounted plate (21) and the integrated plate (22) are arranged relative to each other; the shock-absorbing pad layer (18) is located between the skid-mounted plate (21) and the integrated plate (22); and the LNG gasification module, the refrigerant liquefaction module, the NG reheating module and the phase change energy storage module are arranged on the integrated plate (22).

3. The LNG phase change energy storage skid-mounted gasifier according to claim 1, characterized in that: A deflection baffle (3) is also provided in the shell side (4) of the NG reheating module.

4. The LNG phase change energy storage skid-mounted gasifier according to claim 1, characterized in that: The LNG gasification module is provided with a safety valve group (8) and a pressure indicator (9).

5. The LNG phase change energy storage skid-mounted gasifier according to claim 1, characterized in that: The intermediate medium is a cryogenic working fluid, which circulates and transfers cold energy between the LNG gasification module and the refrigerant liquefaction module. The cryogenic working fluid is selected from at least one of alkanes, fluorocarbons or liquid CO2.

6. The LNG phase change energy storage skid-mounted gasifier according to claim 1, wherein the refrigerant is a low-temperature working fluid selected from at least one of fluorocarbons or liquid CO2.

7. The LNG phase change energy storage skid-mounted gasifier according to any one of claims 1 to 6, characterized in that: The phase change energy storage module comprises a shell, wherein a multi-layer bracket (13) is arranged in the shell, a packaging tube (26) is arranged on the bracket (13), a microcapsule (27) is encapsulated in the packaging tube (26), and a phase change material (28) is arranged in the microcapsule (27); and a spiral coil (14) is arranged between adjacent brackets (13), and a refrigerant circulates in the spiral coil (14).

8. The LNG phase change energy storage skid-mounted gasifier according to claim 7, characterized in that: The shell of the microcapsule (27) is made of a low-temperature resistant polymer material, and the polymer is selected from at least one of polyamide, polyurethane, polyurea and polyester.

9. The LNG phase change energy storage skid-mounted gasifier according to claim 7, characterized in that: The LNG phase-change energy storage skid-mounted gasifiers can be arranged in parallel.

10. The method for operating an LNG phase change energy storage skid-mounted gasifier according to any one of claims 1 to 9, characterized in that: The steps include: S1: LNG is fed into the LNG gasification module, where it exchanges heat with the gaseous intermediate medium in the E1 / E2 shell side. After initial gasification, it enters the NG reheating module, where it undergoes countercurrent reheating with the gaseous refrigerant to complete the gasification process. It can then enter the downstream natural gas pipeline network. S2: After exchanging heat with the low-temperature LNG, the gaseous intermediate medium liquefies and falls to the refrigerant liquefaction module, where it exchanges heat with the gaseous refrigerant. After the heat exchange, the intermediate medium vaporizes and rises again, completing the intermediate medium circulation heat exchange. S3. When the fluctuation rate of the LNG flow entering the LNG gasification module reaches a preset value, it is considered that the LNG flow has entered a peak or valley stage. When the input LNG flow rises to near the peak value, the gaseous refrigerant exchanges heat with the liquid intermediate medium and cools down to liquefaction before entering the phase change energy storage module, where the cold energy is stored. When the input LNG flow drops to near the valley value, the cold energy in the phase change energy storage module is released to the liquid refrigerant to supplement the cooling, thereby maintaining the refrigerant's external transmission temperature and achieving energy storage peak regulation. S4. After the liquid refrigerant achieves energy storage and peak regulation, it is sent to the downstream for cooling and then reheated to complete the refrigerant circulation and heat exchange.

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