Plate-fin heat exchange device for quickly starting and stopping liquid air energy storage system

Abstract

The utility model discloses a plate-fin heat exchange device for quick start and stop of a liquid air energy storage system. The plate-fin heat exchange device comprises a plate-fin heat exchanger core arranged in the plate-fin heat exchange device. The hot end of the plate-fin heat exchanger core is provided with a hot end heat conduction and heat exchange unit, the cold end of the plate-fin heat exchanger core is provided with a cold end heat conduction and heat exchange unit, and fluid channels are arranged in the hot end heat conduction and heat exchange unit and the cold end heat conduction and heat exchange unit. A hot end temperature sensor is arranged at the hot end of the plate-fin heat exchanger core body, and a cold end temperature sensor is arranged at the cold end of the plate-fin heat exchanger core body. The cold end heat conduction and heat exchange unit and the hot end heat conduction and heat exchange unit are additionally arranged at the cold end and the hot end of the plate-fin heat exchanger core body respectively, so that the temperature range of the cold end and the hot end under the normal operation working condition is maintained in the shutdown period of a liquid air energy storage system, the requirement of NB / T 47006 is met, direct starting in the next energy storage period is facilitated, and the energy storage efficiency is improved. And the response time of the liquid air energy storage system is shortened.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid air energy storage, and more specifically to a plate-fin heat exchange device capable of rapid start and stop. Background Art

[0002] As my country proposes to build a new power system with new energy as the main body, the scale of new energy installed capacity has grown rapidly. However, due to the intermittent and volatile nature of renewable energy, as the proportion of grid access increases, it will affect the stable operation of the power grid. Energy storage, as a highly flexible regulating resource in the power grid, has the dual functions of power supply and load, and will become a key support for the new power system.

[0003] Among many energy storage technologies, liquid air energy storage is a new type of large-scale grid energy storage technology with outstanding advantages such as high energy storage density, site selection not restricted by geographical conditions, high safety and long life. It is expected to become one of the most promising new energy storage technologies. The air liquefaction link is one of the most important links in the entire liquid air energy storage system, and the plate-fin heat exchanger, as the core equipment of this link, has a great impact on the electricity-to-electricity conversion efficiency of the entire system. Due to its excellent heat transfer performance, the plate-fin heat exchanger is widely used in low-temperature heat exchange fields such as air separation industry and natural gas liquefaction. However, unlike liquid air energy storage, the application of plate-fin heat exchangers in the field of liquid air energy storage should match the operating characteristics of frequent start and stop of energy storage. According to the requirements of NB / T 47006, when cooling and heating, the plate-fin heat exchanger shall not exceed 1°C / min, the cooling or heating speed shall not exceed 30°C / h, and the instantaneous temperature difference between the working fluid and the system shall not exceed 30°C. After stopping during normal operation, the plate-fin heat exchanger will gradually become consistent due to its good thermal conductivity, which is better than aluminum. At the beginning of the next energy storage cycle, if NB / T 47006, the startup time of the heat exchanger alone may exceed 1 hour. At the same time, this process requires pre-cooling and preheating of the working fluid, which will also affect the efficiency of the energy storage system and does not meet the flexible response characteristics of the energy storage system's frequent start and stop. If it is started directly, a large alternating cold and hot stress will be generated inside the heat exchanger, affecting the service life of the plate-fin heat exchanger. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system, so as to maintain the temperature of the cold and hot ends of the plate-fin heat exchanger to meet the requirements during the shutdown of the liquid air energy storage system, thereby shortening the startup time of the liquid air energy storage system.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows.

[0006] A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system, comprising a plate-fin heat exchanger core arranged inside the plate-fin heat exchanger; a hot end of the plate-fin heat exchanger core is provided with a hot end heat conduction heat exchange unit for exchanging heat with the hot end of the plate-fin heat exchanger, a cold end of the plate-fin heat exchanger core is provided with a cold end heat conduction heat exchange unit for exchanging heat with the cold end of the plate-fin heat exchanger, and fluid channels for heat exchange are provided in both the hot end heat conduction heat exchange unit and the cold end heat conduction heat exchange unit; a hot end temperature sensor for collecting the hot end temperature of the plate-fin heat exchanger core is provided at the hot end of the plate-fin heat exchanger core, and a cold end temperature sensor for collecting the cold end temperature of the plate-fin heat exchanger core is provided at the cold end of the plate-fin heat exchanger core.

[0007] To further optimize the technical solution, the hot-end heat conduction heat exchange unit and the cold-end heat conduction heat exchange unit are respectively arranged inside the plate-fin heat exchange device through a hot-end head and a cold-end head.

[0008] To further optimize the technical solution, the hot-end heat conduction and heat exchange unit is provided with a hot-end fluid inlet end and a hot-end fluid outlet end for exchanging heat at the hot end of the plate-fin heat exchanger core, and the hot-end fluid inlet end and the hot-end fluid outlet end are respectively connected to the fluid channel in the hot-end heat conduction and heat exchange unit.

[0009] To further optimize the technical solution, the cold-end heat conduction heat exchange unit is provided with a cold-end fluid inlet end and a cold-end fluid outlet end for heat exchange at the cold end of the plate-fin heat exchanger core, and the cold-end fluid inlet end and the cold-end fluid outlet end are respectively connected to the fluid channel in the cold-end heat conduction heat exchange unit.

[0010] To further optimize the technical solution, the flow directions of the fluid in the hot-end heat transfer unit and the cold-end heat transfer unit are respectively perpendicular to the axial direction of the plate-fin heat exchanger core.

[0011] To further optimize the technical solution, a plurality of temperature sensors for collecting the temperature inside the plate-fin heat exchanger core are axially arranged inside the plate-fin heat exchanger core.

[0012] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0013] The utility model provides a plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system. A cold end heat conduction heat exchange unit and a hot end heat conduction heat exchange unit are respectively added to the cold end and the hot end of the plate-fin heat exchanger core. During the shutdown of the liquid air energy storage, cold and hot fluids are introduced to enable the cold end heat conduction heat exchange unit and the hot end heat conduction heat exchange unit to achieve heat conduction with the heat exchange core, so that the liquid air energy storage system maintains the temperature range of the cold and hot ends under normal operating conditions during the shutdown period, meets the requirements of NB / T 47006, avoids the time spent on re-establishing the temperature gradient when starting next time, facilitates direct startup of the next energy storage cycle, shortens the response time of the liquid air energy storage system, and reduces the impact of frequent start and stop of the liquid air energy storage system on the plate-fin heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the utility model;

[0015] Figure 2 This is the air liquefaction flow chart of the utility model.

[0016] Among them: 1. hot end heat conduction heat exchange unit, 2. hot end head, 3. cold end heat conduction heat exchange unit, 4. cold end head, 5. plate-fin heat exchanger core, 6. hot end temperature sensor, 7. cold end temperature sensor, 8. temperature sensor, 9. gas-liquid separator, 10. low-temperature throttle valve, 101. cold end fluid inlet, 102. cold end fluid outlet, 201. hot end fluid inlet, 202. hot end fluid outlet, 11. compression unit air, 12. reflux gas, 13. cold storage system air. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] A plate-fin heat exchange device for rapid start and stop of liquid air energy storage system, combined with Figure 1 As shown, it includes a plate-fin heat exchanger core 5 arranged in a plate-fin heat exchange device, a hot end heat conduction heat exchange unit 1 is arranged at the hot end of the plate-fin heat exchanger core 5, which is used to exchange heat at the hot end of the plate-fin heat exchanger, and a cold end heat conduction heat exchange unit 3 is arranged at the cold end of the plate-fin heat exchanger core 5, which is used to exchange heat at the cold end of the plate-fin heat exchanger, and the hot end heat conduction heat exchange unit 1 and the cold end heat conduction heat exchange unit 3 are respectively attached and contacted with the hot end face and the cold end face of the plate-fin heat exchanger core 5. The hot end of the plate-fin heat exchanger refers to the end of the plate-fin heat exchanger with a higher temperature under normal operating conditions, and the cold end of the plate-fin heat exchanger refers to the end of the plate-fin heat exchanger with a lower temperature under normal operating conditions.

[0019] The hot end heat conduction heat exchange unit 1 is arranged inside the plate-fin heat exchange device through the hot end head 2, and the cold end heat conduction heat exchange unit 3 is arranged inside the plate-fin heat exchange device through the cold end head 4. The hot end heat conduction heat exchange unit 1 and the cold end heat conduction heat exchange unit 3 are respectively located between the plate-fin heat exchanger core 5 and the hot end head and the cold end head, and are in contact with the hot end and the cold end of the plate-fin heat exchanger core, so that heat conduction between the hot end heat conduction heat exchange unit of the plate-fin heat exchanger and the plate-fin heat exchanger core and heat conduction between the cold end heat conduction heat exchange unit of the plate-fin heat exchanger and the plate-fin heat exchanger core can be achieved.

[0020] The hot end heat conduction heat exchange unit 1 and the cold end heat conduction heat exchange unit 3 do not interfere with the internal fluid channel of the plate-fin heat exchanger. The hot end heat conduction heat exchange unit 1 and the cold end heat conduction heat exchange unit 3 are both provided with fluid channels for exchanging heat between the hot end and the cold end of the plate-fin heat exchanger core.

[0021] The hot end heat transfer unit 1 is provided with a hot end fluid inlet 201 and a hot end fluid outlet 202, which are respectively connected to the fluid channel in the hot end heat transfer unit 1, so as to exchange heat at the hot end of the plate-fin heat exchanger core 5.

[0022] The cold end heat transfer unit 3 is provided with a cold end fluid inlet 101 and a cold end fluid outlet 102, which are respectively connected to the fluid channel in the cold end heat transfer unit 3 for heat exchange at the cold end of the plate-fin heat exchanger core 5.

[0023] The flow direction of the fluid in the hot end heat transfer unit 1 and the cold end heat transfer unit 3 is perpendicular to the axis direction of the plate-fin heat exchanger core, and the hot end heat transfer unit 1 and the cold end heat transfer unit 3 do not operate simultaneously with other channel fluids in the plate-fin heat exchanger.

[0024] A hot end temperature sensor 6 is provided at the hot end of the plate-fin heat exchanger core 5 for collecting the hot end temperature of the plate-fin heat exchanger core. A cold end temperature sensor 7 is provided at the cold end of the plate-fin heat exchanger core 5 for collecting the cold end temperature of the plate-fin heat exchanger core. A plurality of temperature sensors 8 are axially provided inside the plate-fin heat exchanger core 5 for collecting the temperatures at different positions inside the plate-fin heat exchanger core, and the number of temperature sensors can be adjusted according to the actual length of the plate-fin heat exchanger core.

[0025] During operation, the utility model adds a cold end heat transfer unit and a hot end heat transfer unit to the cold end and the hot end of the plate-fin heat exchanger core respectively, and uses the heat conduction method to enable the plate-fin heat exchanger to maintain the temperature gradient under normal operating conditions after parking, so as to facilitate rapid startup at the next start, improve the response time of the liquid air energy storage system, and effectively reduce the influence of fatigue stress on the plate-fin heat exchanger. The utility model includes the following steps:

[0026] S1. Set the temperature of the cold end of the plate-fin heat exchanger under normal operating conditions, take the arithmetic mean of the temperatures of each stream, and record it as T1; take the arithmetic mean of the temperatures of each stream at the hot end, and record it as T2; the temperature of the cold end of the plate-fin heat exchanger after parking is recorded as T 1n , the temperature of the hot end is recorded as T 2n , cold end temperature difference ΔT1=T 1n -T1, hot end temperature difference ΔT2 = T 2n -T2;

[0027] S2. When the plate-fin heat exchanger operates normally, the hot-end heat transfer unit and the cold-end heat transfer unit do not operate;

[0028] S3. After the plate-fin heat exchanger stops, determine whether to start the heat transfer unit according to the values ​​of ΔT1 and ΔT2;

[0029] S4. For the cold end of the plate-fin heat exchanger, when ΔT1 is greater than 30°C, the heat transfer unit of the cold end of the plate-fin heat exchanger starts to work, and the cold fluid flows in from the cold end fluid inlet 101 and flows out from the cold end outlet 102. When ΔT1 is between 0 and 30°C, the operation can be stopped according to the actual situation;

[0030] For the hot end of the plate-fin heat exchanger, when ΔT2 is greater than 30°C, the heat transfer unit at the cold end of the plate-fin heat exchanger starts to work, and the cold fluid flows in from the hot end fluid inlet 201 and flows out from the hot end fluid outlet 202. When ΔT2 is between 0 and 30°C, the operation can be stopped according to actual conditions.

[0031] The following is an illustration of the real-time effect of a 10MW / 40MWh liquid air energy storage system. The schematic diagram of the air liquefaction process is as follows: Figure 2 As shown, the compression unit air 11 from the air compression unit enters the plate-fin heat exchanger, and is liquefied by heat exchange and cooling with the reflux gas 12 in the gas-liquid separator 9 and the cold storage system air 13 from the cold storage system. The cooled high-pressure liquid air is depressurized by the low-temperature throttle valve 10, and is stored in the liquid air storage tank through the gas-liquid separator 9. The temperature of the liquid air storage tank is -167.98°C.

[0032] During the steady-state operation of the system, the normal operating temperatures of each stream in the plate-fin heat exchanger are shown in Table 1.

[0033] Table 1 Normal operating parameters of each stream of the plate-fin heat exchanger of the liquid air energy storage system

[0034] parameter unit Flow 11 Flow 12 Flow 13 Inlet temperature ℃ 34.13 -164.98 -155.34 Outlet temperature ℃ -160 23.35 36.24

[0035] A cold end heat conduction heat exchange unit and a hot end heat conduction heat exchange unit are added at both ends of the plate-fin heat exchanger core. At the same time, a temperature transmitter for measuring the cold end and hot end core temperatures is provided on the plate-fin heat exchanger. According to the normal operating temperature of each stream in the plate-fin heat exchanger, the average temperature of the cold end is determined to be -160.11°C, and the average temperature of the hot end is 31.24°C.

[0036] At the same time, the inlet fluid of the cold-end heat transfer unit is set to the low-temperature air evaporated from the liquid air storage tank, with a temperature of -167.98°C; the inlet stream 201 of the hot-end heat transfer unit is set to the normal temperature air in the cold storage system, with a temperature of 36.24°C.

[0037] When the liquid air energy storage system is shut down, the temperature value measured by the cold-end temperature sensor is subtracted from the average temperature of each stream during the cold-end operation process, -160.11°C, and the temperature difference is recorded as ΔT1. When the calculated ΔT1>30°C, the cold-end heat transfer unit starts working and stops working when ΔT1 meets any value less than 30°C.

[0038] Similarly, the temperature value measured by the hot-end temperature sensor is subtracted from the average temperature of each stream during the hot-end operation process, 31.24°C. The absolute value of the temperature difference is recorded as ΔT2. When the calculated ΔT2>30°C, the hot-end heat transfer unit starts to work and stops working when ΔT2 meets any value less than 30°C.

[0039] According to the above method, the temperature of the cold end and the hot end of the plate-fin heat exchanger are maintained within 30°C of the normal operating temperature, meeting the requirements of NB / T 47006. When the plate-fin heat exchanger is cooled and heated, in order to prevent thermal shock, the temperature change rate shall not be greater than 1°C / min, the cooling or heating rate shall not exceed 30°C / h, and the instantaneous temperature difference between the working fluid and the system shall not be greater than 30°C. When the next energy storage cycle is started, the working fluid can be directly introduced into each channel without preheating or precooling.

Claims

1. A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system, comprising a plate-fin heat exchanger core (5) arranged inside the plate-fin heat exchange device; characterized in that: The hot end of the plate-fin heat exchanger core (5) is provided with a hot end heat conduction heat exchange unit (1) for performing heat exchange on the hot end of the plate-fin heat exchanger, and the cold end of the plate-fin heat exchanger core (5) is provided with a cold end heat conduction heat exchange unit (3) for performing heat exchange on the cold end of the plate-fin heat exchanger. Fluid channels for heat exchange are provided in both the hot end heat conduction heat exchange unit (1) and the cold end heat conduction heat exchange unit (3); the hot end of the plate-fin heat exchanger core (5) is provided with a hot end temperature sensor (6) for collecting the hot end temperature of the plate-fin heat exchanger core, and the cold end of the plate-fin heat exchanger core (5) is provided with a cold end temperature sensor (7) for collecting the cold end temperature of the plate-fin heat exchanger core.

2. A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system according to claim 1, characterized in that: The hot end heat conduction heat exchange unit (1) and the cold end heat conduction heat exchange unit (3) are arranged inside the plate-fin heat exchange device through a hot end head (2) and a cold end head (4), respectively.

3. A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system according to claim 1, characterized in that: The hot end heat transfer unit (1) is provided with a hot end fluid inlet (201) and a hot end fluid outlet (202) for performing heat exchange on the hot end of the plate-fin heat exchanger core (5); the hot end fluid inlet (201) and the hot end fluid outlet (202) are respectively connected to a fluid channel in the hot end heat transfer unit (1).

4. A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system according to claim 1, characterized in that: The cold end heat transfer unit (3) is provided with a cold end fluid inlet (101) and a cold end fluid outlet (102) for heat exchange at the cold end of the plate-fin heat exchanger core (5); the cold end fluid inlet (101) and the cold end fluid outlet (102) are respectively connected to the fluid channel in the cold end heat transfer unit (3).

5. A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system according to claim 1, characterized in that: The flow directions of the fluid in the hot-end heat conduction heat exchange unit (1) and the cold-end heat conduction heat exchange unit (3) are respectively perpendicular to the axis direction of the plate-fin heat exchanger core.

6. A plate-fin heat exchange device for rapid start and stop of a liquid air energy storage system according to claim 1, characterized in that: A plurality of temperature sensors (8) for collecting the temperature inside the plate-fin heat exchanger core (5) are arranged along the axial direction inside the plate-fin heat exchanger core.

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