Molten salt heat exchange system and control method thereof

Abstract

The invention belongs to the technical field of fused salt heat exchange systems, and provides a fused salt heat exchange system and a control method thereof.The fused salt heat exchange system comprises a hot fused salt storage tank, a hot fused salt pump outlet pump valve subsystem arranged on the hot fused salt storage tank, a cold fused salt storage tank and a hot tank accident inversion subsystem; the hot tank accident dumping subsystem comprises a hot molten salt tank dumping pipeline of which the two ends are respectively connected with the hot molten salt pump outlet pump valve subsystem and the cold molten salt storage tank, and a hot molten salt tank dumping shut-off valve arranged on the hot molten salt tank dumping pipeline; when an accident occurs in the hot molten salt tank, the hot molten salt tank pouring shut-off valve is opened, and molten salt enters the cold molten salt tank through the hot molten salt tank pouring pipeline, so that the molten salt in the hot molten salt tank is poured into the cold molten salt tank, the leakage of the molten salt is prevented, on one hand, the economic loss is reduced, and on the other hand, the personal injury caused by the leakage of the molten salt is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of molten salt heat exchange systems, and in particular relates to a molten salt heat exchange system and a control method thereof. Background Art

[0002] Solar thermal power generation generally uses molten salt as a heat absorption, heat storage and heat exchange medium. The heat exchange process of solar thermal power generation is to extract hot molten salt at about 565℃ from the hot salt tank and exchange heat through the steam generation system to produce water vapor, which then enters the steam turbine power generation system to generate power.

[0003] When the hot molten salt tank is damaged or molten salt leaks, the current molten salt heat exchange system cannot effectively handle it, resulting in molten salt leakage, causing economic losses, and even personal injury caused by molten salt leakage. In addition, the current molten salt heat exchange system cannot effectively utilize the valley electricity of the power grid and the electricity of abandoned wind and solar power. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a molten salt heat exchange system and a control method thereof. When an accident occurs in the hot molten salt tank, the molten salt can enter the cold molten salt tank through the hot molten salt tank pouring pipe, thereby pouring the molten salt in the hot molten salt tank into the cold molten salt tank to prevent the leakage of the molten salt. On the one hand, it reduces economic losses, and on the other hand, it reduces personal injuries caused by the leakage of molten salt.

[0005] In order to achieve the above objectives, in a first aspect, the present invention provides a molten salt heat exchange system, which adopts the following technical solution:

[0006] A molten salt heat exchange system comprises a hot molten salt storage tank, a hot molten salt pump outlet pump valve subsystem arranged on the hot molten salt storage tank, a cold molten salt storage tank, and a hot tank accident tank tipping subsystem;

[0007] The hot tank accident tank dumping subsystem comprises a hot molten salt tank dumping pipe having two ends respectively connected to the hot molten salt pump outlet pump valve subsystem and the cold molten salt storage tank, and a hot molten salt tank dumping shut-off valve arranged on the hot molten salt tank dumping pipe; when an accident occurs to the hot molten salt tank, the hot molten salt tank dumping shut-off valve is opened, and the molten salt enters the cold molten salt tank through the hot molten salt tank dumping pipe.

[0008] Furthermore, the molten salt pump outlet pump valve subsystem includes a molten salt pump, and a molten salt pump outlet branch pipe connected to the molten salt pump; the molten salt pump outlet branch pipe is connected to the molten salt pump outlet main pipe, and the molten salt pump outlet main pipe is provided with a first flow meter; the molten salt pump outlet main pipe is located on the side of the first flow meter away from the molten salt pump, and is connected to the molten salt pump outlet main pipe recycling pipeline through a fourth tee; the molten salt pump outlet main pipe recycling pipeline is provided with a molten salt pump outlet main pipe recycling valve.

[0009] Furthermore, a check valve and a shut-off valve are sequentially arranged on the outlet branch of the molten salt pump along the flow direction of the pump outlet; the outlet branch of the molten salt pump is connected with a minimum flow recirculation branch of the molten salt pump through a tee; the minimum flow recirculation branch of the molten salt pump is connected to the molten salt storage tank; the minimum flow recirculation branch of the molten salt pump is provided with a minimum flow recirculation branch regulating valve of the molten salt pump; the tee connecting the outlet branch of the molten salt pump and the minimum flow recirculation branch of the molten salt pump is located between the check valve and the shut-off valve on the outlet branch of the molten salt pump.

[0010] Furthermore, a thermostatic pump outlet pump valve subsystem is provided on the cold molten salt storage tank; the thermostatic pump outlet pump valve subsystem includes a thermostatic pump, and a thermostatic pump outlet branch pipe connected to the thermostatic pump; the thermostatic pump outlet branch pipe is connected to the thermostatic pump outlet main pipe, and a second flow meter is provided on the thermostatic pump outlet main pipe; a thermostatic pump outlet main pipe recirculation pipeline is connected to the thermostatic pump outlet main pipe, located on the side of the second flow meter away from the thermostatic pump; a thermostatic pump outlet main pipe recirculation valve is provided on the thermostatic pump outlet main pipe recirculation pipeline.

[0011] Furthermore, a cold salt temperature control subsystem is arranged between the hot molten salt pump outlet pump valve subsystem and the temperature control pump outlet pump valve subsystem; the cold salt temperature control subsystem includes a cold salt temperature control branch pipe, and a temperature control cold salt regulating valve and a temperature control shut-off valve arranged on the cold salt temperature control branch pipe; the temperature control cold salt regulating valve is close to the temperature control pump outlet pump valve subsystem, and the temperature control shut-off valve is close to the hot molten salt pump outlet pump valve subsystem.

[0012] Furthermore, the outlet branch of the thermostatic pump is connected to a minimum flow recirculation branch of the thermostatic pump through a tee; the minimum flow recirculation branch of the thermostatic pump is provided with a regulating valve; the minimum flow recirculation branch of the thermostatic pump is connected to the minimum flow recirculation main pipe of the thermostatic pump; the minimum flow recirculation main pipe of the thermostatic pump is connected to the cold molten salt storage tank. Furthermore, a valley electric heating subsystem is provided between the outlet pump valve subsystem of the thermostatic pump and the hot molten salt storage tank; the valley electric heating subsystem includes a valley electric heating inlet main pipe connected to the outlet pump valve subsystem of the thermostatic pump, a valley electric heating inlet shut-off valve, a valley electric heating regulating valve, a fifth flowmeter and an external molten salt electric heater arranged on the valley electric heating inlet main pipe in sequence, a valley electric heating outlet main pipe connected to the external molten salt electric heater arranged on the valley electric heating inlet main pipe, and a valley electric heating outlet shut-off valve arranged on the valley electric heating outlet main pipe; the valley electric heating outlet main pipe is connected to the hot molten salt storage tank.

[0013] Furthermore, a steam generating subsystem is arranged between the hot molten salt pump outlet pump valve subsystem and the cold molten salt storage tank; the steam generating subsystem includes a superheater branch and a reheater branch connected to the hot molten salt pump outlet pump valve subsystem; a superheater, a third flowmeter and a superheater branch regulating valve are arranged in sequence on the superheater branch; a reheater, a fourth tube flowmeter and a reheater branch regulating valve are arranged in sequence on the reheater tube.

[0014] In order to achieve the above object, in a second aspect, the present invention also provides a molten salt heat exchange system control method, which adopts the following technical solution:

[0015] A molten salt heat exchange system control method uses the molten salt heat exchange system as described in the first aspect, including: when an accident occurs in the hot molten salt tank, the hot molten salt tank inverting shut-off valve is opened, and the molten salt enters the cold molten salt tank through the hot molten salt tank inverting pipe.

[0016] Furthermore, when the hot molten salt tank is in an accidental tank dumping operation, the hot molten salt pump is started; the shut-off valve on the outlet branch of the hot molten salt pump is closed, and the regulating valve on the minimum flow recirculation branch of the hot molten salt pump is opened, and the molten salt at the outlet of the hot molten salt pump enters the minimum flow recirculation main pipe of the hot molten salt pump; the hot molten salt tank dumping shut-off valve is opened, and the isolation valve of the minimum flow recirculation main pipe of the hot molten salt pump is closed, and the molten salt enters the cold molten salt tank through the hot molten salt tank dumping pipeline, so that the molten salt in the hot molten salt tank is poured into the cold molten salt tank;

[0017] When the cold molten salt tank is in an accidental tank dumping operation, start the thermostatic pump; open the shut-off valve on the outlet branch of the thermostatic pump, close the superheater branch regulating valve, the reheater branch regulating valve and the shut-off valve on the outlet branch of the hot molten salt pump; open the thermostatic cold salt regulating valve, the thermostatic shut-off valve and the hot molten salt pump outlet main pipe recirculation valve, and the molten salt at the outlet of the thermostatic pump enters the hot molten salt pump outlet main pipe recirculation pipeline through the cold salt thermostatic branch pipe, and enters the hot molten salt tank through the hot molten salt pump outlet main pipe recirculation pipeline.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention is provided with a hot tank accident dumping subsystem. When an accident occurs in the hot molten salt tank, the hot molten salt tank dumping shut-off valve is opened, and the molten salt enters the cold molten salt tank through the hot molten salt tank dumping pipeline, thereby pouring the molten salt in the hot molten salt tank into the cold molten salt tank to prevent leakage of the molten salt, which reduces economic losses on the one hand and personal injuries caused by leakage of molten salt on the other.

[0020] 2. In the present invention, by using the cold salt temperature control subsystem in conjunction with the hot molten salt pump outlet main pipe recirculation pipeline, when an accident occurs in the cold molten salt tank, the molten salt at the outlet of the temperature control pump can be controlled and adjusted accordingly to enter the hot molten salt pump outlet main pipe recirculation pipeline, and then enter the hot molten salt tank through the hot molten salt pump outlet main pipe recirculation pipeline, so that the heat exchange system also has the function of tank dumping in the event of a cold tank accident.

[0021] 3. The design temperature of the valve of the pump and valve subsystem near the outlet of the hot molten salt pump is higher than the design temperature of the valve of the pump and valve subsystem of the thermostatic pump outlet. The price of the regulating valve at the same pressure and temperature is higher than that of the shut-off valve. Based on this, in the present invention, the thermostatic cold salt regulating valve is arranged at one end near the thermostatic pump outlet pump and valve subsystem, and the thermostatic shut-off valve is arranged at one end near the outlet of the hot molten salt pump. The design temperature of the thermostatic cold salt regulating valve can be reduced, thereby reducing the investment cost of the valve group. The present invention is conducive to reducing investment through the arrangement sequence of the thermostatic cold salt regulating valve and the thermostatic shut-off valve.

[0022] 4. In the present invention, a valley electric heating subsystem is provided, and the valley electric heating subsystem includes a valley electric heating inlet main pipe connected to the temperature regulating pump outlet pump valve subsystem, a valley electric heating inlet shut-off valve, a valley electric heating regulating valve, a fifth flowmeter and an external molten salt electric heater arranged in sequence on the valley electric heating inlet main pipe, a valley electric heating outlet main pipe connected to the external molten salt electric heater arranged on the valley electric heating inlet main pipe, and a valley electric heating outlet shut-off valve arranged on the valley electric heating outlet main pipe; the valley electric heating outlet main pipe is connected to the hot molten salt storage tank; the valley electric heating outlet main pipe can effectively utilize the valley electricity of the power grid and the abandoned wind and solar power.

[0023] 5. Through the present invention, no matter an accident occurs in the cold molten salt tank or the hot molten salt tank, the tank can be reversed. During normal operation, when the temperature of the molten salt in the cold molten salt tank drops to a certain value, a part of the hot molten salt in the hot molten salt tank can be poured into the cold molten salt tank through the hot tank accident reverse tank subsystem of the hot molten salt tank to heat the cold molten salt and prevent the cold molten salt from solidifying. On the one hand, this saves the power consumption of the anti-condensation electric heater located in the cold molten salt tank, and on the other hand, it can also cancel the anti-condensation electric heater (including but not limited to the immersion anti-condensation electric heater) set inside the cold molten salt tank in the traditional solution, thereby reducing project investment.

[0024] 6. The present invention only needs to set a flow meter on the outlet main pipe of the hot melt salt pump, and does not need to set a flow meter on each outlet branch pipe of the hot melt salt pump. Similarly, it only needs to set a flow meter on the outlet main pipe of the thermostatic pump, and does not need to set a flow meter on each outlet branch pipe of the thermostatic pump, thereby saving expensive flow meter investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings in the specification that constitute a part of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments of this embodiment and their descriptions are used to explain this embodiment and do not constitute improper limitations on this embodiment.

[0026] Figure 1 This is a schematic diagram of a molten salt heat exchange system according to Example 1 of the present invention;

[0027] Figure 2 It is a schematic diagram of the arrangement of the outlet pipeline of the hot molten salt pump of the present invention;

[0028] Figure 3 It is a schematic diagram of the arrangement of the pipeline system from the outlet of the hot molten salt pump to the outlet main pipe flow meter of the hot salt pump of the present invention;

[0029] Figure 4a This is a diagram of the outlet pipeline system of the hot molten salt pump with a valley electric heating subsystem with a vacuum breaking hole added thereto of the present invention;

[0030] Figure 4b This is a diagram of the outlet pipeline system of the hot molten salt pump without the valley electric heating subsystem and with the vacuum breaking hole added;

[0031] Figure 5 The structure of the vacuum breaking hole of the present invention is set;

[0032] Figure 6 This is a system diagram of the present invention after the valley electric heating subsystem is eliminated;

[0033] Figure 7a This is a hot molten salt pump outlet piping system diagram (with valley electric heating subsystem) with a recirculation main pipe flow meter added to the present invention;

[0034] Figure 7b This is a hot molten salt pump outlet piping system diagram with a recirculation main pipe flowmeter added to the present invention (without the valley electric heating subsystem);

[0035] Among them, 1A is the first molten salt pump; 1B is the second molten salt pump; 1C is the third molten salt pump; 2A is the first check valve; 2B is the second check valve; 2C is the third check valve. 3A, first shut-off valve; 3B, second shut-off valve; 3C, third shut-off valve; 4A, first regulating valve; 4B, second regulating valve; 4C, third regulating valve; 5, superheater; 6, reheater; 7A, first evaporator; 7B, second evaporator; 8, preheater; 9A, superheater branch pipe regulating valve; 9B, reheater branch pipe regulating valve; 10, preheater outlet shut-off valve; 101, hot molten salt tank tank inversion shut-off valve; 102, fifth three-way; 103, hot molten salt tank tank inversion pipeline; 11, hot molten salt pump outlet main pipe recirculation valve; 12, hot molten salt pump minimum flow recirculation main pipe isolation valve; 16A, first three-way; 16B, second three-way; 16C, third three-way; 21, first flowmeter; 22, second flowmeter; 23, third flowmeter; 24, fourth flowmeter; 25, fifth flowmeter;

[0036] 31A, first thermostatic pump; 31B, second thermostatic pump; 32A, fourth check valve; 32B, fifth check valve; 33A, fourth shut-off valve; 33B, fifth shut-off valve; 34A, fourth regulating valve; 34B, fifth regulating valve; 35, thermostatic pump outlet main pipe recirculation valve;

[0037] 41. Valley electric heating inlet shut-off valve; 42. Valley electric heating regulating valve; 43. External molten salt electric heater; 44. Valley electric heating outlet shut-off valve; 45. Valley electric heating inlet mother pipe; 46. Valley electric heating outlet mother pipe; 51. Temperature-adjusting cold salt regulating valve; 52. Temperature-adjusting shut-off valve; 53. Cold salt temperature-adjusting branch pipe;

[0038] 61A, outlet branch of the first hot molten salt pump; 61B, outlet branch of the second hot molten salt pump; 61C, outlet branch of the third hot molten salt pump; 62, outlet main pipe of the hot molten salt pump; 63, temperature mixing main pipe; 64A, superheater branch pipe; 64B, reheater branch pipe; 65, front main pipe of evaporator; 66A, first evaporator branch pipe; 66B, second evaporator branch pipe; 67, front main pipe of preheater; 68, outlet main pipe of preheater;

[0039] 71A, outlet branch of the first thermostatic pump; 71B, outlet branch of the second thermostatic pump; 72A, minimum flow recirculation branch of the first thermostatic pump; 72B, minimum flow recirculation branch of the second thermostatic pump; 73, minimum flow recirculation main pipe of the thermostatic pump; 74, recirculation pipeline of the thermostatic pump outlet main pipe; 75, thermostatic pump outlet main pipe;

[0040] 81A, minimum flow recirculation branch of the first hot molten salt pump; 81B, minimum flow recirculation branch of the second hot molten salt pump; 81C, minimum flow recirculation branch of the third hot molten salt pump; 82, minimum flow recirculation main pipe of the hot molten salt pump; 83, recirculation pipeline of the hot molten salt pump outlet main pipe; 91, fourth tee; 92, fifth tee;

[0041] N1, first interface; N2, second interface; N3, third interface; N4, fourth interface; N5, fifth interface; N11, sixth interface; N12, seventh interface; N13, eighth interface; N14, ninth interface; N15, tenth interface; N16, eleventh interface; N6, twelfth interface. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0044] Embodiment 1:

[0045] Solar thermal power generation generally uses molten salt as a heat absorption, heat storage and heat exchange medium. The heat exchange process of solar thermal power generation is to extract hot molten salt at about 565℃ from the hot salt tank, and use the steam generation system to exchange heat between the molten salt and water to generate water vapor, and then the water vapor enters the steam turbine power generation system to generate power.

[0046] When the CSP power station is not generating electricity, the steam generation system enters the shutdown state. If it is a short shutdown, the molten salt will be stored in the steam generation system; if it is a long shutdown, in order to reduce the heat loss of the entire system and prevent the solidification of the molten salt equipment and pipelines and cause safety accidents, the molten salt in the entire steam generation system, including the superheater, reheater, evaporator, and preheater, will be drained into the molten salt tank or salt draining tank, and the entire system will be emptied. The system will be refilled with salt the next day and enter the normal operation mode. The steam generation system of the solar thermal power generation unit often repeats the process of salt filling and salt draining.

[0047] In order to complete the debugging and operation of the molten salt pump in one system, including single-unit debugging, pump startup, parallel operation of multiple pumps, daily salt charging and salt removal of the steam generation system, etc., it is necessary to design a scientific, economical and reasonable outlet pipeline system of the molten salt pump in the solar thermal power station and its debugging and operation method.

[0048] On the one hand, when starting up, a venting system needs to be set up at the highest point of the pipeline layout, and the venting system includes a venting valve, a venting pipeline, etc.; on the other hand, when stopping operation, a salt release system needs to be reasonably set up at the low point of the pipeline layout, and the salt release system includes a salt release valve, a salt release pipeline, etc. However, the venting pipeline and the salt release pipeline are both pipelines with smaller diameters. During normal operation, when the venting valve and the salt release valve are closed, there is a flow dead zone between the valves on the venting pipeline and the salt release pipeline and the main pipeline, which objectively increases the risk of molten salt solidification in this dead zone during operation.

[0049] In order to measure the flow rate of molten salt, expensive ultrasonic flowmeters are usually configured. The use of different combinations of pipeline equipment (such as valves, flowmeters, etc.) at the outlet of the molten salt pump, as well as different pipeline layout methods, plays a critical and decisive role in the functional realization of the molten salt pump outlet pipeline system of the CSP power station. In order to reduce the project investment of the CSP power station, the number of pipeline equipment should be minimized while ensuring that the required functions can be achieved. In the past, the outlet pipeline system of the molten salt pump of a CSP power station was relatively complex, and failed to combine the combination of pipeline equipment and pipeline layout of the outlet of the molten salt pump well. Therefore, multiple sets of expensive valves and flowmeters were set up, resulting in a high investment cost of the CSP power station, which in turn led to poor economic efficiency of the CSP power station project.

[0050] In order to solve at least one of the above problems, Figure 1 As shown, this embodiment provides a molten salt heat exchange system, including a hot molten salt storage tank, a hot molten salt pump outlet pump valve subsystem connected to the hot molten salt storage tank, a cold molten salt storage tank, a temperature control pump outlet pump valve subsystem connected to the cold molten salt storage tank, a cold salt temperature control subsystem, a steam generation subsystem, and a hot tank accident tank tipping subsystem, etc.

[0051] In the outlet pump valve subsystem of the thermostatic pump, there are two recirculation pipelines connected to the cold molten salt storage tank, one is the minimum flow recirculation main pipe of the thermostatic pump, and the other is the outlet main pipe recirculation pipeline of the thermostatic pump. In the outlet pump valve subsystem of the hot salt pump, there are two recirculation pipelines connected to the hot molten salt storage tank, one is the minimum flow recirculation main pipe of the hot molten salt pump, and the other is the outlet main pipe recirculation pipeline of the hot molten salt pump.

[0052] The molten salt pump outlet pump valve subsystem includes a molten salt pump, a check valve, a shut-off valve, a minimum flow recirculation branch of the molten salt pump, a regulating valve of the minimum flow recirculation branch of the molten salt pump, a molten salt pump outlet main pipe 62 and a first flow meter 21; the number of the molten salt pumps is greater than or equal to one, and is not limited to the three given in this embodiment.

[0053] Taking three hot-melt salt pumps as an example, optionally, the hot-melt salt pump outlet pump valve subsystem includes a first hot-melt salt pump 1A, a second hot-melt salt pump 1B and a third hot-melt salt pump 1C. The first hot-melt salt pump 1A is connected to the hot-melt salt storage tank through a first interface N1, and the first hot-melt salt pump 1A is connected to a first hot-melt salt pump outlet branch 61A, and the first hot-melt salt pump outlet branch 61A is provided with a first check valve 2A and a first shut-off valve 3A. The second hot-melt salt pump 1B is connected to the hot-melt salt storage tank through a second interface N2, and the second hot-melt salt pump 1B is connected to a second hot-melt salt pump outlet branch 61B, and the second hot-melt salt pump outlet branch 61B is provided with a second check valve 2B and a second shut-off valve 3B. The third molten salt pump 1C is connected to the molten salt storage tank via a third interface N3, and a third molten salt pump outlet branch pipe 61C is connected to the third molten salt pump 1C, and a third check valve 2C and a third shut-off valve 3C are provided on the third molten salt pump outlet branch pipe 61C.

[0054] The first hot molten salt pump outlet branch pipe 61A, the second hot molten salt pump outlet branch pipe 61B and the third hot molten salt pump outlet branch pipe 61C are connected to the hot molten salt pump outlet main pipe 62, and the first flow meter 21 is arranged on the hot molten salt pump outlet main pipe 62.

[0055] The first hot molten salt pump outlet branch 61A is connected to the first hot molten salt pump minimum flow recirculation branch 81A through the first tee 16A, and the first hot molten salt pump minimum flow recirculation branch 81A is provided with a first regulating valve 4A. The second hot molten salt pump outlet branch 61B is connected to the second hot molten salt pump minimum flow recirculation branch 81B through the second tee 16B, and the second hot molten salt pump minimum flow recirculation branch 81B is provided with a second regulating valve 4B. The third hot molten salt pump outlet branch 61C is connected to the third hot molten salt pump minimum flow recirculation branch 81C through the third tee 16C, and the third hot molten salt pump minimum flow recirculation branch 81C is provided with a third regulating valve 4C.

[0056] The first molten salt pump minimum flow recirculation branch 81A, the second molten salt pump minimum flow recirculation branch 81B and the third molten salt pump minimum flow recirculation branch 81C are connected to a molten salt pump minimum flow recirculation main pipe 82; the molten salt pump minimum flow recirculation main pipe 82 is connected to the molten salt storage tank through a fourth interface N4. A molten salt pump minimum flow recirculation main pipe isolation valve 12 is provided between the molten salt pump minimum flow recirculation main pipe 82 and the fourth interface N4.

[0057] The hot molten salt pump outlet main pipe 62 is located on the side of the first flowmeter 21 away from the hot molten salt pump, and is connected to the hot molten salt pump outlet main pipe recirculation pipeline 83 through the fourth three-way 91. The hot molten salt pump outlet main pipe recirculation pipeline 83 is provided with a hot molten salt pump outlet main pipe recirculation valve 11; the hot molten salt pump outlet main pipe recirculation valve 11 is connected to the hot molten salt storage tank through the fifth interface N5. Specifically, the outlet point of the hot molten salt pump outlet main pipe recirculation pipeline 83 from the hot molten salt pump outlet main pipe 62 is located at the highest point of the hot molten salt pump outlet main pipe 62. Therefore, the hot molten salt pump outlet main pipe recirculation pipeline 83 also serves as a venting pipeline, and the hot molten salt pump outlet main pipe recirculation valve 11 also serves as a venting valve.

[0058] The cold salt temperature regulating subsystem includes a cold salt temperature regulating branch pipe 53, a temperature mixing main pipe 63, a temperature regulating cold salt regulating valve 51 and a temperature regulating shut-off valve 52. The cold salt temperature regulating branch pipe 53 is connected to the hot molten salt pump outlet main pipe 62 and the temperature mixing main pipe 63 through components such as a tee. On the cold salt temperature regulating branch pipe 53, the temperature regulating cold salt regulating valve 51 and the temperature regulating shut-off valve 52 are arranged in sequence from away from the temperature mixing main pipe 63 to the temperature mixing main pipe 63. The advantage of the above arrangement is that the price of the regulating valve under the same pressure and temperature is higher than that of the shut-off valve, and the design temperature of the valve close to the temperature mixing main pipe 63 is higher than that of the valve far from the temperature mixing main pipe 63, thereby reducing the investment cost of the valve group. For example, the design temperature of the temperature-adjusting shut-off valve 52 is 575°C, and due to the shut-off function of the temperature-adjusting shut-off valve 52, the design temperature of the temperature-adjusting cold salt regulating valve 51 can be reduced to 375°C, that is, the design temperature is taken according to the working condition of the cold salt before temperature mixing, rather than the design temperature according to the working condition of the hot salt after temperature mixing, thereby reducing the investment cost of the valve group.

[0059] The thermostatic pump outlet pump valve subsystem includes a thermostatic pump, a check valve, a shut-off valve, a regulating valve of the minimum flow recirculation branch of the molten salt pump, a second flow meter 22, and a thermostatic pump outlet main pipe 75. The number of the thermostatic pumps is greater than or equal to one, and is not limited to the two given in this embodiment.

[0060] Taking two thermostatic pumps as an example, optionally, the thermostatic pump outlet pump valve subsystem includes a first thermostatic pump 31A and a second thermostatic pump 31B. The first thermostatic pump 31A is connected to the cold molten salt storage tank through the sixth interface N11, and the first thermostatic pump 31A is connected to the first thermostatic pump outlet branch 71A; the first thermostatic pump outlet branch 71A is provided with a fourth check valve 32A and a fourth shut-off valve 33A. The second thermostatic pump 31B is connected to the cold molten salt storage tank through the seventh interface N12, and the second thermostatic pump 31B is connected to the second thermostatic pump outlet branch 71B; the second thermostatic pump outlet branch 71B is provided with a fifth check valve 32B and a fifth shut-off valve 33B.

[0061] The outlet branch pipe 71A of the first thermostatic pump is connected to the minimum flow recirculation branch pipe 72A of the first thermostatic pump through a tee; the minimum flow recirculation branch pipe 72A of the first thermostatic pump is provided with a fourth regulating valve 34A. The outlet branch pipe 71B of the second thermostatic pump is connected to the minimum flow recirculation branch pipe 72B of the second thermostatic pump through a tee; the minimum flow recirculation branch pipe 72B of the second thermostatic pump is provided with a fifth regulating valve 34B. The minimum flow recirculation branch pipe 72A of the first thermostatic pump and the minimum flow recirculation branch pipe 72B of the second thermostatic pump are connected to the minimum flow recirculation main pipe 73 of the thermostatic pump; the minimum flow recirculation main pipe 73 of the thermostatic pump is connected to the cold molten salt storage tank through the eighth interface N13.

[0062] The first temperature control pump outlet branch pipe 71A and the second temperature control pump outlet branch pipe 71B are connected to the temperature control pump outlet main pipe 75; the second flow meter 22 is arranged on the temperature control pump outlet main pipe 75. The temperature control pump outlet main pipe 75 is connected to the cold salt temperature control branch pipe 53.

[0063] The thermostatic pump outlet main pipe 75 is located on the side of the second flowmeter 22 away from the thermostatic pump, and is connected to a thermostatic pump outlet main pipe recirculation pipeline 74; the thermostatic pump outlet main pipe recirculation pipeline 74 is provided with a thermostatic pump outlet main pipe recirculation valve 35; the thermostatic pump outlet main pipe recirculation pipeline 74 is connected to the cold molten salt storage tank through the ninth interface N14. Specifically, the lead-out point of the thermostatic pump outlet main pipe recirculation pipeline 74 from the thermostatic pump outlet main pipe 75 is located at the highest point of the thermostatic pump outlet main pipe 75, so the thermostatic pump outlet main pipe recirculation pipeline 74 also serves as a venting pipeline, and the thermostatic pump outlet main pipe recirculation valve 35 also serves as a venting valve.

[0064] The steam generation subsystem includes a superheater 5, a reheater 6, a first evaporator 7A, a second evaporator 7B, a preheater 8 and the like.

[0065] The superheater 5 and the reheater 6 are connected to the temperature mixing main pipe 63 through the superheater branch pipe 64A and the reheater branch pipe 64B, respectively. The outlet pipe of the superheater 5 is provided with a third flowmeter 23 and a superheater branch pipe regulating valve 9A; the outlet pipe of the reheater 6 is provided with a fourth flowmeter 24 and a reheater branch pipe regulating valve 9B; the outlet pipes of the superheater 5 and the outlet pipes of the reheater 6 are connected to the evaporator front main pipe 65. The first evaporator 7A and the second evaporator 7B are connected to the evaporator front main pipe 65 through the first evaporator branch pipe 66A and the second evaporator branch pipe 66B, respectively. The first evaporator 7A and the second evaporator 7B are connected to the preheater 8 through the preheater front main pipe 67. The preheater 8 is connected to the cold molten salt storage tank via the preheater outlet main pipe 68 and the tenth interface N15; the preheater outlet main pipe 68 is provided with a preheater outlet shut-off valve 10.

[0066] Specifically, the third flowmeter 23 is located at the outlet of the superheater 5 instead of at the inlet of the superheater 5, which can reduce the design temperature of the third flowmeter 23, thereby reducing the investment cost of the third flowmeter 23. The fourth flowmeter 24 is located at the outlet of the reheater 6 instead of at the inlet of the reheater 6, which can reduce the design temperature of the fourth flowmeter 24, thereby reducing the investment cost of the fourth flowmeter 24.

[0067] The hot tank accident tank dumping subsystem is connected to the hot molten salt pump minimum flow recirculation main pipe 82 through the hot molten salt tank dumping pipe 103 and the fifth three-way 102; the hot molten salt tank dumping pipe 103 is connected to the cold molten salt storage tank through the eleventh interface N16. A hot molten salt tank dumping shut-off valve 101 is provided on the hot molten salt tank dumping pipe 103. The hot molten salt pump minimum flow recirculation main pipe isolation valve 12 is located between the fifth three-way 102 and the fourth interface N4.

[0068] like Figure 2 and Figure 3 As shown, the molten salt heat exchange system also includes a piping system arrangement used in conjunction with the hot molten salt pump outlet pump valve subsystem.

[0069] The outlet pipe of the molten salt pump is connected in the horizontal direction, and then a check valve and a tee connected to the minimum flow recirculation branch of the molten salt pump are arranged in sequence on the horizontal pipe. The third end of the tee is connected to the minimum flow recirculation branch of the molten salt pump in the horizontal direction. The minimum flow recirculation branch of the molten salt pump is inserted downward into the molten salt storage tank after passing through at least one elbow.

[0070] From the hot molten salt pump outlet to the steam generation system, a horizontal "H" type The type of arrangement is: starting from the outlet of the hot molten salt pump, as the pipe section is extended, the elevation of each pipe section gradually increases or at least remains horizontal until a certain high point (called the first high point of the pipeline system), at the location of the first high point of the pipeline system, at least one pipe section is connected in the horizontal direction, and then it extends downward to a certain low point (called the first low point of the pipeline system), and then at least one pipe section is connected in the horizontal direction at the location of the low point, and then it extends upward to connect to the superheater or reheater inlet. Among them, extending downward from the first high point of the pipeline system to the first low point of the pipeline system, at least one pipe section is connected in the horizontal direction at the location of the first low point of the pipeline system, and then extending upward, a U-shaped bend is formed.

[0071] The entire piping system at the outlet of the hot molten salt pump is divided into two parts by the first high point of the piping system. The first half is the part between the hot molten salt pump and the first high point of the piping system, which is arranged in an "inverted U" pattern; the second half is the part between the first high point of the piping system and the steam generation system (including the steam generation system), which is arranged in a "positive U" pattern. The connection between the "inverted U" and the "positive U" constitutes a horizontal "self" type. The layout type.

[0072] A fourth three-way 91 for venting the hot molten salt pump outlet main pipe 62 is arranged on the pipe section where the first high point is located, and the fourth three-way 91 for venting the hot molten salt pump outlet main pipe 62 is connected to the hot molten salt pump outlet main pipe recirculation pipeline 83. A hot molten salt pump outlet main pipe recirculation valve 11 is arranged on the hot molten salt pump outlet main pipe recirculation pipeline 83. The hot molten salt pump outlet main pipe recirculation valve 11 is the valve with the highest arrangement height position, and therefore, it also has the function of a venting valve for the entire pipeline system of the hot molten salt pump outlet. The fourth three-way 91 for venting the hot molten salt pump main pipe is located at the end of the first flowmeter 21 away from the hot molten salt pump. Therefore, when the superheater branch pipe regulating valve 9A, the reheater branch pipe regulating valve 9B, and the temperature regulating shut-off valve 52 are closed, and the hot molten salt pump outlet main pipe recirculation valve 11 is opened, the flow on the hot molten salt pump outlet main pipe recirculation pipeline 83 can be read by the first flowmeter 21.

[0073] A hot molten salt pump outlet main pipe salt discharge pipeline is arranged on the pipe section where the first low point is located. A hot molten salt pump outlet main pipe salt discharge valve is arranged on the hot molten salt pump outlet main pipe salt discharge pipeline. Among all the valves between the first high point and the superheater inlet, the hot molten salt pump outlet main pipe salt discharge valve is the valve with the lowest arrangement height position, and therefore, it also has the function of salt discharge of the entire pipeline system of the hot molten salt pump outlet. Furthermore, the hot molten salt pump outlet main pipe salt discharge pipeline is connected to the salt discharge tank.

[0074] From the tee connecting the minimum flow recirculation branch of the molten salt pump to the molten salt storage tank, a "step-by-step" layout is adopted, that is: starting from the tee connecting the minimum flow recirculation branch of the molten salt pump, as the pipe section is extended, the elevation of each pipe section is gradually reduced or at least maintained horizontal until it is connected to the molten salt storage tank.

[0075] A plurality of molten salt pump minimum flow recirculation branch pipes are aggregated into a molten salt pump minimum flow recirculation mother pipe 82; from the tee connected to the molten salt pump minimum flow recirculation branch pipe to the molten salt pump minimum flow recirculation mother pipe 82, and then to the molten salt storage tank, a "step-by-step" layout is adopted, that is: starting from the tee connected to the molten salt pump minimum flow recirculation branch pipe, as the pipe section is extended, the elevation of each pipe section is gradually reduced or at least kept horizontal until it is connected to the molten salt storage tank.

[0076] On the hot molten salt pump outlet main pipe recirculation pipeline 83, from the hot molten salt pump outlet main pipe recirculation valve 11 to the hot molten salt storage tank, a "step-by-step" layout is adopted, that is: starting from the hot molten salt pump outlet main pipe recirculation valve 11, as the pipe section is extended, the elevation of each pipe section is gradually reduced or at least maintained horizontal until it is connected to the hot molten salt storage tank.

[0077] According to the above arrangement, among all the valves between the outlet of the molten salt pump and the first high point, the regulating valve on the minimum flow recirculation branch of the molten salt pump is the valve with the lowest arrangement height. Therefore, the regulating valve on the minimum flow recirculation branch of the molten salt pump also serves as a salt discharge valve of the pipeline system between the outlet of the molten salt pump and a certain high point. In other words, the minimum flow recirculation branch of the molten salt pump also has the function of a salt discharge pipeline.

[0078] When a molten salt pump stops running, the interlock opens the regulating valve of the minimum flow recirculation branch of the molten salt pump corresponding to the molten salt pump on the same side, thereby effectively reducing the pipeline vibration caused by the salt hammer effect. The regulating valve of the minimum flow recirculation branch of the molten salt pump has a fast opening function, thereby minimizing the pipeline vibration caused by the salt hammer effect. The salt hammer effect refers to the sudden change in the flow rate of molten salt in a pressurized molten salt pipeline due to some external reasons (such as sudden closure of the valve, sudden shutdown of the molten salt pump), which causes a shock wave and causes the pipeline to vibrate under force.

[0079] According to the above arrangement, among all the valves between the first high point and the superheater inlet, the hot molten salt pump outlet main pipe salt discharge valve on the hot molten salt pump outlet main pipe salt discharge pipeline is the valve with the lowest arrangement height. Therefore, in this embodiment, the hot molten salt pump outlet main pipe salt discharge valve on the hot molten salt pump outlet main pipe salt discharge pipeline serves as the salt discharge valve for the hot molten salt pump outlet main pipe salt discharge pipeline and the steam generating system.

[0080] Embodiment 2:

[0081] This embodiment provides a molten salt heat exchange system. Different from Embodiment 1, in this embodiment, a valley electric heating subsystem is provided between the hot molten salt storage tank and the temperature regulating pump outlet pump valve subsystem.

[0082] The valley electric heating subsystem includes a valley electric heating inlet main pipe 45 connected to the temperature regulating pump outlet pump valve subsystem, a valley electric heating inlet shut-off valve 41, a valley electric heating regulating valve 42, a fifth flowmeter 25 and an external molten salt electric heater 43 arranged on the valley electric heating inlet main pipe 45 in sequence, a valley electric heating outlet main pipe 46 connected to the external molten salt electric heater 43 arranged on the valley electric heating inlet main pipe, and a valley electric heating outlet shut-off valve 44 arranged on the valley electric heating outlet main pipe 46; the valley electric heating outlet main pipe 46 is connected to the hot molten salt storage tank through a twelfth interface N6.

[0083] The valley electricity heating inlet main pipe 45 is connected to the temperature control pump outlet main pipe 75 and the cold salt temperature control branch pipe 53 through a tee. The valley electricity of the valley electricity heating subsystem comes from the cheap new energy electricity of abandoned wind and solar power, or from the surplus electricity of thermal power units, or from the valley electricity of the power grid.

[0084] Embodiment 3:

[0085] The present embodiment provides a molten salt heat exchange system. Different from Embodiment 1 and / or Embodiment 2, in the present embodiment, a vacuum breaking hole is provided on the pipe section where the minimum flow recirculation main pipe 82 of the hot molten salt pump is inserted into the hot molten salt tank and / or the pipe section where the minimum flow recirculation main pipe 73 of the thermostatic pump is inserted into the cold molten salt tank, which is located above the highest liquid level of the hot molten salt tank and the cold molten salt tank and below the tank top. On the one hand, at the moment when the regulating valve on the minimum flow recirculation branch of the thermostatic pump is opened, the gas in the cold molten salt storage tank enters the outlet branch of the thermostatic pump through the vacuum breaking hole, thereby destroying the vacuum. Similarly, at the moment when the regulating valve on the minimum flow recirculation branch of the hot molten salt pump is opened, the gas in the hot molten salt storage tank enters the outlet branch of the hot molten salt pump through the vacuum breaking hole, thereby destroying the vacuum. On the other hand, after the regulating valve on the minimum flow recirculation branch of the thermostatic pump is opened, a leakage channel leading to the cold molten salt tank is formed through the outlet branch of the thermostatic pump and the minimum flow recirculation branch of the thermostatic pump. Similarly, after the regulating valve on the minimum flow recirculation branch of the hot molten salt pump is opened, a leakage channel leading to the hot molten salt storage tank is formed through the outlet branch of the hot molten salt pump and the minimum flow recirculation branch of the hot molten salt pump. The above two aspects can prevent the generation of molten salt gas-liquid two-phase flow, thereby effectively reducing the pipeline vibration caused by salt hammer.

[0086] Taking the hot molten salt pump as an example, when the last running hot molten salt pump stops, the air in the tank enters the hot molten salt pump minimum flow recirculation mother pipe 82 through the vacuum breaking hole, and then enters the pump outlet branch pipe through the regulating valve that is interlocked and opened when the hot molten salt pump stops, thereby cleverly destroying the vacuum behind the check valve caused by the sudden stop of the pump, avoiding the molten salt gasification caused by the sudden pressure drop and the resulting gas-liquid two-phase flow impact, salt hammer hitting the valve, pipeline vibration, sudden increase in structural load and other problems. The vacuum breaking hole is suitable for both the pipe section of the hot molten salt pump minimum flow recirculation mother pipe 82 inserted into the hot molten salt tank, and the pipe section of the thermostatic pump minimum flow recirculation mother pipe 73 inserted into the cold molten salt tank.

[0087] Embodiment 4:

[0088] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a method for starting a single molten salt pump. Taking the first molten salt pump 1A as an example, the first molten salt pump 1A is started according to the following steps:

[0089] S101, when the first molten salt pump 1A is turned on, the first regulating valve 4A is fully opened as the first molten salt pump 1A is started; at the same time, the first shut-off valve 3A is opened as the first molten salt pump 1A is started, and the recirculation valve 11 of the outlet main pipe of the molten salt pump is opened;

[0090] S102, during the load increase process of the first hot molten salt pump 1A on the same side, the first regulating valve 4A is remotely operated according to the flow of the first flow meter 21, and its regulating opening is gradually reduced. When the flow of the first hot molten salt pump 1A on the same side (converted according to the flow measured by the first flow meter 21) reaches or exceeds a certain set value, the first regulating valve 4A is closed. Explanation: Since the molten salt flow of the hot molten salt pump = the molten salt flow measured by the first flow meter 21 + the molten salt flow flowing into the hot molten salt tank through the first regulating valve 4A, when the flow measured by the first flow meter 21 is ≥ the minimum flow of a hot molten salt pump (for example, 15% of the rated flow of a hot molten salt pump), it can be concluded that the molten salt flow of the hot molten salt pump is ≥ the minimum flow of a hot molten salt pump (for example, 15% of the rated flow of a hot molten salt pump), and thus it can be judged that the first regulating valve 4A can be gradually reduced until it is closed.

[0091] Embodiment 5:

[0092] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a single-unit debugging method for a hot molten salt pump. When the hot molten salt pump single-unit debugging is carried out, when the first hot molten salt pump 1A single-unit debugging is carried out, the second hot molten salt pump 1B and the third hot molten salt pump 1C are in a shutdown state, and the single-unit debugging of the first hot molten salt pump 1A is carried out according to the following steps:

[0093] S201, starting the first molten salt pump 1A according to the starting method of the first molten salt pump 1A in Example 4;

[0094] S202, close the superheater branch regulating valve 9A, the reheater branch regulating valve 9B, and the temperature control shut-off valve 52, and open the hot molten salt pump outlet main pipe recirculation valve 11, thereby forming a flow loop from the first hot molten salt pump 1A, the first check valve 2A, the first hot molten salt pump outlet branch 61A, the fourth shut-off valve 3A, the hot molten salt pump outlet main pipe 62, the first flow meter 21, the hot molten salt pump outlet main pipe recirculation pipeline 83, the hot molten salt pump outlet main pipe recirculation valve 11 to the hot molten salt tank, so as to realize the single unit debugging of the first hot molten salt pump 1A.

[0095] Similarly, the second molten salt pump 1B and the third molten salt pump 1C can be debugged separately.

[0096] Embodiment 6:

[0097] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a method for starting a single thermostatic pump. When starting the first thermostatic pump, taking the first thermostatic pump 31A as an example, the first thermostatic pump 31A is started according to the following steps:

[0098] S301, when the first thermostatic pump 31A is turned on, the fourth regulating valve 34A on the same side is fully opened when the first thermostatic pump 31A is started; at the same time, the fourth shut-off valve 33A on the same side is opened when the first thermostatic pump 31A is started, and the thermostatic pump outlet main pipe recirculation valve 35 is opened;

[0099] S302, during the load increase process of the first temperature control pump 31A on the same side, the fourth regulating valve 34A is remotely operated according to the flow of the second flow meter 22, and its adjustment opening is gradually closed. When the flow of the first temperature control pump 31A on the same side (converted according to the flow measured by the second flow meter 22) reaches or exceeds a certain set value, the fourth regulating valve 34A of the minimum flow recirculation branch of the molten salt pump is closed.

[0100] Embodiment 7:

[0101] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a single-unit debugging method for a thermostatic pump. When the single-unit debugging of the thermostatic pump is carried out, when the first thermostatic pump 31A is being debugged, the second thermostatic pump 31B is in a shutdown state, and the single-unit debugging of the first thermostatic pump 31A is carried out according to the following steps:

[0102] S401, starting the first temperature control pump 31A according to the starting method of the first temperature control pump 31A in Example 6;

[0103] S402, close the temperature-adjusting cold salt regulating valve 51 and the valley electric heating inlet shut-off valve 41, and open the temperature-adjusting pump outlet main pipe recirculation valve 35, thereby forming a flow loop from the first temperature-adjusting pump 31A, the first check valve 32A, the first temperature-adjusting pump outlet branch pipe 71A, the fourth shut-off valve 33A, the temperature-adjusting pump outlet main pipe 75, the second flow meter 22, the temperature-adjusting pump outlet main pipe recirculation pipeline 74, the temperature-adjusting pump outlet main pipe recirculation valve 35 to the cold molten salt tank, so as to realize the single-body debugging of the first temperature-adjusting pump 31A.

[0104] Similarly, the second temperature control pump 31B and the third temperature control pump 31C may be debugged separately.

[0105] Embodiment 8:

[0106] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a method for filling a steam generation system with cold salt. Before the hot molten salt enters the steam generation system, the relatively low temperature cold molten salt is first filled into the steam generation system, which can reduce the metal heating rate of the steam generation system, reduce metal stress, and reduce the life loss rate of the equipment. Before the steam generation system is started, when filling the steam generation system with cold salt, the steam generation system salt filling work is carried out according to the following steps:

[0107] S501, start at least one temperature regulating pump, close all the hot molten salt pumps and their corresponding first shut-off valves 3A, second shut-off valves 3B and third shut-off valves 3C;

[0108] S502, open the pump outlet shut-off valve corresponding to the thermostatic pump on the same side (for example, the fourth shut-off valve 33A corresponding to the first thermostatic pump 31A), open the thermostatic cold salt regulating valve 51, the thermostatic shut-off valve 52, the superheater branch pipe regulating valve 9A, and the reheater branch pipe regulating valve 9B, close the thermostatic pump outlet mother pipe recirculation valve 35 and the valley electric heating inlet shut-off valve 41, and the molten salt at the thermostatic pump outlet enters the steam generation system through the cold salt thermostatic subsystem;

[0109] S503, open the preheater outlet shut-off valve 10, and the temperature-regulated cold salt enters the cold molten salt tank from the steam generating system. When the second flow meter 22, the third flow meter 23, and the fourth flow meter 24 stably reach the first set value, the steam generating system is filled with cold salt. The temperature regulating pump is turned off, and the preheater outlet shut-off valve 10 is closed.

[0110] Embodiment 9:

[0111] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a steam generation system startup method. The steam generation system startup process is carried out according to the following steps. At the same time, in order to cooperate with the steam generation system startup, the pipeline system is operated according to the following steps:

[0112] S601, according to the steps in Example 8, the process of charging cold salt in the steam generating system is completed;

[0113] S602, start at least one molten salt pump (for example, the first molten salt pump 1A), open the shut-off valve at the pump outlet on the same side (for example, the first shut-off valve 3A) and the molten salt pump outlet main pipe recirculation valve 11, and fill the molten salt pump outlet pump valve subsystem with hot salt.

[0114] S603, open the preheater outlet shut-off valve 10, close the hot molten salt pump outlet mother pipe recirculation valve 11, start at least one temperature regulating pump (e.g., the first temperature regulating pump 31A), open the shut-off valve at the pump outlet on the same side (e.g., the fourth shut-off valve 33A), adjust the opening of the temperature regulating shut-off valve 52 and the frequency of the hot molten salt pump, so that when the outlet mixed temperature of the cold salt temperature regulating subsystem reaches a certain set value, the steam generation system is charged with mixed temperature salt through the cold salt temperature regulating subsystem;

[0115] S604, adjusting the opening of the temperature regulating shut-off valve 52 and the frequencies of the hot molten salt pump and the temperature regulating pump, gradually adjusting the heating rate of the mixed temperature salt, and realizing the startup of the steam generating system.

[0116] Embodiment 10:

[0117] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a steam generation system operation method. The steam generation system operation process is carried out according to the following steps. At the same time, in order to cooperate with the operation of the steam generation system, the pipeline system operation is carried out according to the following steps:

[0118] S701, according to the previous embodiment, complete the steam generation system startup process;

[0119] S702. Determine the steam parameter requirements according to the power generation load requirements, and then adjust the opening of the thermostatic shut-off valve 52 and the frequencies of the hot molten salt pump and the thermostatic pump to achieve the required steam parameters.

[0120] Embodiment 11:

[0121] The present embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, the present embodiment provides a method for parallel pumping of multiple molten salt pumps. Based on the above-mentioned pipeline system, according to the increase in the load required by the steam generation system, multiple molten salt pumps are started. When the first molten salt pump 1A has been started, the second molten salt pump 1B and the third molten salt pump 1C are in a shutdown state. The second molten salt pump 1B is started and parallel pumped according to the following steps, thereby increasing the inlet molten salt flow of the steam generation system, and then increasing the heat load of the steam generation system:

[0122] S801, according to the starting method of the first molten salt pump 1A in the previous embodiment, the first molten salt pump 1A is started;

[0123] S802, when the second molten salt pump 1B is turned on, as the second molten salt pump 1B is started, the second regulating valve 4B on the same side is fully opened; at the same time, as the second molten salt pump 1B is started, the second shut-off valve 3B at the outlet of the molten salt pump on the same side is opened;

[0124] S803, during the load increase process of the second molten salt pump 1B, the second regulating valve 4B is remotely operated according to the flow of the first flow meter 21, and its adjustment opening is gradually closed. When the flow of the second molten salt pump 1B (converted according to the flow measured by the first flow meter 21) reaches or exceeds a certain set value, the second regulating valve 4B is closed.

[0125] Embodiment 12:

[0126] The present embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system as in Example 1, Example 2 and / or Example 3; specifically, the present embodiment provides a method for connecting multiple thermostatic pumps in parallel. According to the increase in the thermostatic load of the steam generation system and the load required by the valley electric heating subsystem, multiple thermostatic pumps are started. When the first thermostatic pump 31A has been started, the second thermostatic pump 31B is in a shutdown state. The second thermostatic pump 31B is started and connected in parallel according to the following steps, thereby increasing the flow rate of the thermostatic pump outlet mother pipe, and then increasing the load of the steam generation system thermostatic or valley electric heating subsystem:

[0127] S901, starting the first temperature regulating pump 31A according to the starting method of the first temperature regulating pump 31A in the previous embodiment;

[0128] S902, when the second temperature regulating pump 31B is turned on, the fifth regulating valve 34B is fully opened as the second temperature regulating pump 31B is started; at the same time, the fifth shut-off valve 33B on the same side is opened as the second temperature regulating pump 31B is started;

[0129] S903, during the load increase process of the second temperature control pump 31B, the fifth regulating valve 34B is remotely operated according to the flow of the second flow meter, and its adjustment opening is gradually closed. When the flow of the second temperature control pump 31B (converted according to the flow measured by the second flow meter 22) reaches or exceeds a certain set value, the fifth regulating valve 34B is closed.

[0130] Embodiment 13:

[0131] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a molten salt heat exchange system salt release method. The molten salt heat exchange system is released according to the following steps:

[0132] S1001, all molten salt pumps are shut down, and the steam generation system is adjusted from the heat exchange operation state to the non-heat exchange operation state. During the shutdown process of the last running molten salt pump, when the forward flow (referring to the flow from the molten salt pump to the steam generation system) measured by the first flow meter 21 drops to a certain set value, the minimum flow recirculation main pipe isolation valve 12 of the molten salt pump is opened, the molten salt tank tank shut-off valve 101 is closed, and the regulating valve corresponding to the molten salt pump on this side is opened, that is, the first regulating valve 4A and the second regulating valve 4B are opened. Regulating valve 4B and the third regulating valve 4C, so that when the last running molten salt pump stops, the remaining molten salt in the pipe section between the molten salt pump and the first high point of the pipeline system flows into the molten salt pump minimum flow recirculation main pipe 82 through the first molten salt pump minimum flow recirculation branch pipe 81A, the second molten salt pump minimum flow recirculation branch pipe 81B and the third molten salt pump minimum flow recirculation branch pipe 81C by gravity, and then enters the molten salt tank through the molten salt pump minimum flow recirculation main pipe 82;

[0133] S1002, open the salt drain valve of the hot molten salt pump outlet main pipe, and the molten salt in the pipe section between the first high point of the pipeline system and the steam generation system (including the steam generation system) enters the salt drain tank through the salt drain pipeline of the hot molten salt pump outlet main pipe by gravity;

[0134] S1003. The molten salt in the salt drainage tank is pumped into the cold molten salt tank or the hot molten salt tank through the salt drainage pump.

[0135] Since the pipeline equipment combination of the molten salt heat exchange system in the present invention can be deeply coupled with its layout type and used in conjunction with it, the salt discharged from the molten salt heat exchange system can be directly discharged into the hot molten salt tank or the salt discharge tank by gravity.

[0136] Embodiment 14:

[0137] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a valley electric heating subsystem operation method. Based on the above pipeline system, the valley electric heating subsystem is operated according to the following steps:

[0138] S1101, start at least one temperature regulating pump, for example, the first temperature regulating pump 31A;

[0139] S1102, open the pump outlet shut-off valve corresponding to the thermostatic pump on the same side, for example, the fourth shut-off valve 33A corresponding to the first thermostatic pump 31A, open the valley electric heating inlet shut-off valve 41 and the valley electric heating regulating valve 42, and the molten salt at the outlet of the thermostatic pump enters the valley electric heating subsystem;

[0140] S1103, connect the external molten salt electric heater to an external power source, such as the valley power of the power grid, the amount of abandoned wind and solar power in the same wind-solar complementary project, etc., and the external molten salt electric heater heats the cold molten salt at the outlet of the thermostatic pump into hot molten salt. Then, open the valley power heating outlet shut-off valve 44, and the heated hot molten salt enters the hot molten salt tank.

[0141] Embodiment 15:

[0142] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides a method for accidental tank dumping of a cold molten salt tank. Based on the above-mentioned pipeline system, when an accident occurs in the cold molten salt tank (such as tank damage, molten salt leakage, etc.), the accidental tank dumping of the cold molten salt tank is performed according to the following steps:

[0143] S1201, start at least one temperature regulating pump, for example, the first temperature regulating pump 31A;

[0144] S1202, open the shut-off valves corresponding to the temperature regulating pumps on the same side, for example, the fourth shut-off valve 33A corresponding to the first temperature regulating pump 31A, close the superheater branch regulating valve 9A, the reheater branch regulating valve 9B, the first shut-off valve 3A, the second shut-off valve 3B and the third shut-off valve 3C, close the valley electric heating inlet shut-off valve 41, open the temperature regulating cold salt regulating valve 51, the temperature regulating shut-off valve 52 and the hot molten salt pump outlet main pipe recirculation valve 11, the molten salt at the outlet of the temperature regulating pump enters the hot molten salt pump outlet main pipe recirculation pipeline 83 through the cold salt temperature regulating branch pipe 53, and then enters the hot molten salt tank through the hot molten salt pump outlet main pipe recirculation pipeline 83.

[0145] Embodiment 16:

[0146] This embodiment provides a molten salt heat exchange system control method, which adopts the molten salt heat exchange system in Example 1, Example 2 and / or Example 3; specifically, this embodiment provides another method for accidental tank dumping of a cold molten salt tank. Based on the above-mentioned pipeline system, when an accident occurs in the cold molten salt tank (such as tank damage, molten salt leakage, etc.), the accidental tank dumping of the cold molten salt tank is performed according to the following steps:

[0147] S1301, start at least one temperature regulating pump, for example, the first temperature regulating pump 31A;

[0148] S1302, open the pump outlet shut-off valve corresponding to the thermostatic pump on the same side, for example, the fourth shut-off valve 33A corresponding to the first thermostatic pump 31A, close the thermostatic cold salt regulating valve 51, open the valley electric heating inlet shut-off valve 41, the valley electric heating regulating valve 42 and the valley electric heating outlet shut-off valve 44, and the molten salt at the outlet of the thermostatic pump enters the valley electric heating subsystem;

[0149] S1303. Regardless of whether the external molten salt electric heater is connected to an external power supply, the valley electric heating outlet shut-off valve 44 is opened, and the molten salt enters the hot molten salt tank, thereby pouring the molten salt in the cold molten salt tank into the hot molten salt tank to prevent leakage of the molten salt, thereby reducing economic losses on the one hand and personal injuries caused by leakage of molten salt on the other.

[0150] The above description is only a preferred embodiment of the present embodiment and is not intended to limit the present embodiment. For those skilled in the art, the present embodiment may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present embodiment shall be included in the protection scope of the present embodiment.

Claims

1. A molten salt heat exchange system, characterized in that: It includes a hot molten salt storage tank, a hot molten salt pump outlet pump valve subsystem arranged on the hot molten salt storage tank, a cold molten salt storage tank, and a hot tank accident tank tipping subsystem; The hot tank accident tank dumping subsystem comprises a hot molten salt tank dumping pipe having two ends respectively connected to the hot molten salt pump outlet pump valve subsystem and the cold molten salt storage tank, and a hot molten salt tank dumping shut-off valve arranged on the hot molten salt tank dumping pipe; when an accident occurs to the hot molten salt tank, the hot molten salt tank dumping shut-off valve is opened, and the molten salt enters the cold molten salt tank through the hot molten salt tank dumping pipe.

2. A molten salt heat exchange system according to claim 1, characterized in that: The molten salt pump outlet pump valve subsystem includes a molten salt pump, and a molten salt pump outlet branch pipe connected to the molten salt pump; the molten salt pump outlet branch pipe is connected to the molten salt pump outlet main pipe, and the molten salt pump outlet main pipe is provided with a first flow meter; the molten salt pump outlet main pipe is connected to a molten salt pump outlet main pipe recirculation pipeline through a fourth tee on the side of the first flow meter away from the molten salt pump on the molten salt pump outlet main pipe; a molten salt pump outlet main pipe recirculation valve is provided on the molten salt pump outlet main pipe recirculation pipeline.

3. A molten salt heat exchange system according to claim 2, characterized in that: A check valve and a shut-off valve are sequentially arranged on the outlet branch of the molten salt pump along the flow direction of the pump outlet; the outlet branch of the molten salt pump is connected with a minimum flow recirculation branch of the molten salt pump through a tee; the minimum flow recirculation branch of the molten salt pump is connected to the molten salt storage tank; the minimum flow recirculation branch of the molten salt pump is provided with a minimum flow recirculation branch regulating valve of the molten salt pump; the tee connecting the outlet branch of the molten salt pump and the minimum flow recirculation branch of the molten salt pump is located between the check valve and the shut-off valve on the outlet branch of the molten salt pump.

4. A molten salt heat exchange system according to claim 1, characterized in that: A thermostatic pump outlet pump valve subsystem is connected to the cold molten salt storage tank; the thermostatic pump outlet pump valve subsystem includes a thermostatic pump and a thermostatic pump outlet branch pipe connected to the thermostatic pump; the thermostatic pump outlet branch pipe is connected to a thermostatic pump outlet main pipe, and a second flow meter is arranged on the thermostatic pump outlet main pipe; a thermostatic pump outlet main pipe recirculation pipeline is connected to the thermostatic pump outlet main pipe, which is located on the side of the second flow meter away from the thermostatic pump; a thermostatic pump outlet main pipe recirculation valve is arranged on the thermostatic pump outlet main pipe recirculation pipeline.

5. A molten salt heat exchange system according to claim 4, characterized in that: A cold salt temperature regulating subsystem is arranged between the hot molten salt pump outlet pump valve subsystem and the temperature regulating pump outlet pump valve subsystem; the cold salt temperature regulating subsystem includes a cold salt temperature regulating branch pipe, and a temperature regulating cold salt regulating valve and a temperature regulating shut-off valve arranged on the cold salt temperature regulating branch pipe; the temperature regulating cold salt regulating valve is close to the temperature regulating pump outlet pump valve subsystem, and the temperature regulating shut-off valve is close to the hot molten salt pump outlet pump valve subsystem.

6. A molten salt heat exchange system according to claim 4, characterized in that: The outlet branch pipe of the temperature regulating pump is connected to the minimum flow recirculation branch pipe of the temperature regulating pump through a tee; the minimum flow recirculation branch pipe of the temperature regulating pump is provided with a regulating valve; the minimum flow recirculation branch pipe of the temperature regulating pump is connected to the minimum flow recirculation main pipe of the temperature regulating pump; the minimum flow recirculation main pipe is connected to the cold molten salt storage tank.

7. A molten salt heat exchange system according to claim 4, characterized in that: A valley electric heating subsystem is arranged between the temperature regulating pump outlet pump valve subsystem and the hot molten salt storage tank; the valley electric heating subsystem includes a valley electric heating inlet main pipe connected to the temperature regulating pump outlet pump valve subsystem, a valley electric heating inlet shut-off valve, a valley electric heating regulating valve, a fifth flowmeter and an external molten salt electric heater arranged on the valley electric heating inlet main pipe in sequence, a valley electric heating outlet main pipe connected to the external molten salt electric heater arranged on the valley electric heating inlet main pipe, and a valley electric heating outlet shut-off valve arranged on the valley electric heating outlet main pipe; the valley electric heating outlet main pipe is connected to the hot molten salt storage tank.

8. The molten salt heat exchange system according to claim 1, characterized in that: A steam generating subsystem is arranged between the hot molten salt pump outlet pump valve subsystem and the cold molten salt storage tank; the steam generating subsystem includes a superheater branch pipe and a reheater branch pipe connected to the hot molten salt pump outlet pump valve subsystem; a superheater, a third flowmeter and a superheater branch pipe regulating valve are arranged in sequence on the superheater branch pipe; a reheater, a fourth pipe flowmeter and a reheater branch pipe regulating valve are arranged in sequence on the reheater pipe.

9. A molten salt heat exchange system control method, characterized in that: The molten salt heat exchange system according to any one of claims 1 to 8 is used, comprising: when an accident occurs in the hot molten salt tank, the hot molten salt tank inverting shut-off valve is opened, and the molten salt enters the cold molten salt tank through the hot molten salt tank inverting pipe.

10. A molten salt heat exchange system control method according to claim 9, characterized in that: When the hot molten salt tank is in an accidental tank dumping operation, start the hot molten salt pump; close the shut-off valve on the outlet branch of the hot molten salt pump, open the regulating valve on the minimum flow recirculation branch of the hot molten salt pump, and the molten salt at the outlet of the hot molten salt pump enters the minimum flow recirculation main pipe of the hot molten salt pump; open the hot molten salt tank dumping shut-off valve, close the isolation valve of the minimum flow recirculation main pipe of the hot molten salt pump, and the molten salt enters the cold molten salt tank through the hot molten salt tank dumping pipeline, so as to pour the molten salt in the hot molten salt tank into the cold molten salt tank; When the cold molten salt tank is in an accidental tank dumping operation, start the thermostatic pump; open the shut-off valve on the outlet branch of the thermostatic pump, close the superheater branch regulating valve, the reheater branch regulating valve and the shut-off valve on the outlet branch of the hot molten salt pump; open the thermostatic cold salt regulating valve, the thermostatic shut-off valve and the hot molten salt pump outlet main pipe recirculation valve, the molten salt at the outlet of the thermostatic pump enters the hot molten salt pump outlet main pipe recirculation pipeline, and enters the hot molten salt tank through the hot molten salt pump outlet main pipe recirculation pipeline.

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