CN118009779A - Fused salt heat-storage energy-release unit and boiler unit deep peak regulation system - Google Patents

Abstract

The invention provides a fused salt heat storage and energy release unit and a boiler unit deep peak regulation system, wherein the fused salt heat storage and energy release unit comprises a fused salt storage assembly, a heat exchange energy storage assembly and a heat exchange energy release assembly, and the fused salt storage assembly comprises a high-temperature fused salt storage tank and a low-temperature fused salt storage tank; the heat exchange energy storage component is connected with the high-temperature molten salt storage tank and the low-temperature molten salt storage tank, and comprises a flue gas heat exchange device and a steam heat exchange device, and molten salt in the low-temperature molten salt storage tank flows into the high-temperature molten salt storage tank after being heated by the flue gas heat exchange device and the steam heat exchange device in sequence; the heat exchange energy release assembly is connected with the high-temperature molten salt storage tank and the low-temperature molten salt storage tank, and comprises a coal dust heating device and a water supply heating device, and molten salt in the high-temperature molten salt storage tank flows into the low-temperature molten salt storage tank after being released by the coal dust heating device and/or the water supply heating device. The invention provides a fused salt heat storage and energy release unit and a boiler unit deep peak regulation system which are flexible in peak regulation and high in energy utilization rate.

Description

Fused salt heat-storage energy-release unit and boiler unit deep peak regulation system

Technical Field

The invention relates to the technical field of boiler peak regulation, in particular to a fused salt heat storage and energy release unit and a boiler unit deep peak regulation system.

Background

Because of the unpredictability and the discontinuity of the renewable energy source power generation, the unstable electric energy is generated to influence the electric energy quality of the power grid, so that part of renewable energy source power generation cannot enter the power grid, and the phenomenon of 'wind abandoning and light abandoning' is generated. In order to solve the problem of low renewable energy power generation networking proportion, the renewable energy power consumption is realized mainly by a mode of peak regulation of a thermal power generating unit with large power generation capacity proportion at present. In order to solve the problems of relatively slow peak load and relatively large hysteresis of the traditional thermal power generation, the energy storage technology of the thermal power generation is improved at present so as to solve the problem of poor peak load regulation performance.

The energy storage technology is used as a technical means for changing energy space-time distribution, so that the peak regulation flexibility of the power station can be greatly improved, and the supply and demand balance problem of a power grid can be relieved. Among the energy storage modes, the molten salt energy storage has the advantages of high energy storage density, long energy storage period and low cost, so that the method becomes one of the peak regulation means of the thermal power generating unit with prospect. The high-load operation in the boiler can be kept through coupling the molten salt energy storage, and meanwhile, the electric load output is reduced, so that the flexible and rapid peak regulation of the power plant is realized. However, conventional molten salt energy storage technology can store and release energy only for high single grade energy, has low energy utilization rate and is easy to cause huge energy waste.

Disclosure of Invention

The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems:

the present invention aims to solve at least one of the technical problems in the related art to some extent.

Therefore, the embodiment of the invention provides a fused salt heat storage and energy release unit and a boiler unit depth peak regulation system, and the fused salt heat storage and energy release unit and the boiler unit depth peak regulation system have the advantage of improving the energy utilization rate.

The fused salt heat storage and energy release unit provided by the embodiment of the invention comprises a fused salt storage assembly, a heat exchange energy storage assembly and a heat exchange energy release assembly, wherein the fused salt storage assembly comprises a high-temperature fused salt storage tank and a low-temperature fused salt storage tank; the heat exchange energy storage component is connected with the high-temperature molten salt storage tank and the low-temperature molten salt storage tank, and comprises a flue gas heat exchange device and a steam heat exchange device, and molten salt in the low-temperature molten salt storage tank flows into the high-temperature molten salt storage tank after being heated by the flue gas heat exchange device and the steam heat exchange device in sequence; the heat exchange energy release assembly is connected with the high-temperature molten salt storage tank and the low-temperature molten salt storage tank, and comprises a coal dust heating device and a water supply heating device, wherein molten salt in the high-temperature molten salt storage tank flows into the low-temperature molten salt storage tank after being released by the coal dust heating device and/or the water supply heating device.

According to the molten salt heat storage and release unit provided by the embodiment of the invention, the molten salt heat storage and release unit can effectively utilize multi-grade energy through the flue gas heat exchange device and the steam heat exchange device, can absorb low-temperature heat sources when the temperature is low, and can absorb high-temperature heat sources when the temperature is high; meanwhile, the fused salt heat storage and energy release unit can realize the opposite-mouth multi-way release of temperature according to different temperatures required by different parts, thereby effectively improving the absorption and utilization efficiency of energy or heat. In addition, the device can heat coal dust through the coal dust heating device, so that the combustion stability of the related boiler in low-load combustion is effectively improved.

In some embodiments, the heat exchange energy storage assembly further comprises an electrical heating device located between the steam heat exchange device and the high temperature molten salt storage tank;

And/or the steam heat exchange device comprises a primary steam heat exchanger and a secondary steam heat exchanger which are sequentially arranged along the flowing direction.

In some embodiments, a bypass for circulating molten salt working medium is further arranged outside the electric heating device, and a switch valve is arranged on the bypass.

In some embodiments, the heat exchange energy release assembly comprises a first energy release branch and a second energy release branch, and after molten salt in the high-temperature molten salt storage tank flows into the first energy release branch and/or the second energy release branch, the molten salt is converged and flows into the low-temperature molten salt storage tank;

The pulverized coal heating device is positioned on the first energy release branch, and the water supply heating devices are at least two in number and are respectively distributed on the first energy release branch and the second energy release branch.

In some embodiments, the feedwater heating device includes a molten salt feedwater medium temperature heat exchanger located on the first energy release branch and a molten salt feedwater superheater and a molten salt feedwater evaporator located on the second energy release branch,

And the molten salt in the high-temperature molten salt storage tank sequentially flows through the pulverized coal heating device and the molten salt water supply medium-temperature heat exchanger through the first energy release branch, and/or sequentially flows through the molten salt water supply superheater and the molten salt water supply evaporator through the second energy release branch and then flows into the low-temperature molten salt storage tank.

In some embodiments, the second energy release branch is further provided with a fused salt water supply low-temperature heat exchanger, the fused salt water supply low-temperature heat exchanger is connected with the boiler unit, and condensed water is connected with the boiler unit through the fused salt water supply low-temperature heat exchanger.

In some embodiments, the heat exchange energy storage assembly further comprises a low-temperature molten salt pump, and molten salt in the low-temperature molten salt storage tank flows into the high-temperature molten salt storage tank through the flue gas heat exchange device and the steam heat exchange device under the drive of the low-temperature molten salt pump;

And/or the heat exchange energy release assembly further comprises a high-temperature molten salt pump, and molten salt in the high-temperature molten salt storage tank flows into the low-temperature molten salt storage tank through the coal dust heating device and the water supply heating device under the driving of the high-temperature molten salt pump.

The boiler unit depth peak regulation system provided by the embodiment of the invention comprises a fused salt heat storage and energy release unit and a boiler circulation unit, wherein the fused salt heat storage and energy release unit is any one of the fused salt heat storage and energy release units; the boiler circulation unit comprises a boiler unit, a steam turbine and a condensate water recovery assembly which are communicated with each other, the boiler unit is matched with the heat exchange energy storage assembly and the heat exchange energy release assembly, the steam turbine is matched with the heat exchange energy release assembly, and the condensate water recovery assembly is matched with the steam turbine and the heat exchange energy storage assembly.

According to the boiler unit depth peak shaving system provided by the embodiment of the invention, the flexible operation degree of the boiler unit under a variable load working condition can be effectively improved by applying the fused salt heat storage and energy release unit, the load response efficiency of a power grid in normal period switching to a high peak period and a low load period is improved, the peak shaving depth of the unit is increased, and the boiler unit depth peak shaving system has important significance in improving the service level of a power system. In addition, the boiler unit deep peak regulation system further utilizes the fused salt heat storage energy release unit to effectively improve the combustion stability of the boiler unit in low load, and meanwhile, the heat utilization rate can be improved in a heat exchange mode when the power grid is in a high load period, so that the fused salt energy cascade utilization in energy release is realized, and compared with the existing energy storage system, the fused salt heat storage energy release system has better heat exchange efficiency and can help to increase the generated energy of a steam turbine.

In some embodiments, the boiler unit comprises a steam release assembly, a smoke exhaust assembly and a coal inlet assembly, wherein the steam release assembly is matched with a steam heat exchange device in the heat exchange and energy storage assembly, the smoke exhaust assembly is matched with the smoke heat exchange device, and the coal inlet assembly is matched with the coal dust heating device;

The steam turbine comprises a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder which are coaxially and sequentially arranged, and steam generated by the boiler unit flows into the steam release assembly and the high-pressure cylinder respectively; at least part of the water supply heating device is connected with the medium pressure cylinder through a pipeline, and part of steam in the high pressure cylinder and at least part of steam and/or liquid generated at the water supply heating device flow into the medium pressure cylinder;

The condensed water recovery assembly comprises at least three steam heaters, at least three air cooling condensers, at least three condensate pumps, at least one steam heater, at least one steam heat exchanger, at least one deaerator and at least one deaerator, wherein steam exhausted from the steam heat exchanger flows into the deaerator through a pipeline; and under the drive of the drive pump set, condensed water generated at the air-cooling condenser and the condensed water pump sequentially flows through the steam heater and the deaerator and flows back into the boiler unit.

In some embodiments, at least one drain is provided at the drive pump stack, the drain being connected to the water inlet of the feedwater heating device.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic structural diagram of a molten salt heat storage and release unit provided by an embodiment of the invention;

Fig. 2 is a schematic structural diagram of a boiler unit depth peak shaving system according to an embodiment of the present invention.

In the figure:

10. A molten salt heat storage and energy release unit; 11. a high temperature molten salt storage tank; 12. a low temperature molten salt storage tank; 13. a flue gas heat exchange device; 14. a steam heat exchange device; 141. a primary steam heat exchanger; 142. a secondary steam heat exchanger; 15. a coal dust heating device; 16. a water supply heating device; 161. a molten salt water supply medium temperature heat exchanger; 162. a molten salt feedwater superheater; 163. a molten salt feed water evaporator; 164. a molten salt water supply low-temperature heat exchanger; 17. an electric heating device; 171. a bypass; 172. opening and closing a valve; 18. a low temperature molten salt pump; 19. a high temperature molten salt pump;

20. A boiler circulation unit; 21. a boiler unit; 211. a steam release assembly; 212. a smoke exhausting assembly; 213. a coal feeding assembly; 22. a steam turbine; 221. a high-pressure cylinder; 222. a medium pressure cylinder; 223. a low pressure cylinder; 23. a condensate recovery assembly; 231. a steam heater; 232. an air-cooling condenser; 233. a condensate pump; 234. a deaerator; 235. driving a pump; 236. a pre-pump; 237. a small turbine.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

The following describes a fused salt heat storage and energy release unit and a boiler unit depth peak regulation system according to an embodiment of the invention with reference to fig. 1-2.

An embodiment of the invention provides a molten salt heat storage and release unit 10, as shown in fig. 1. The fused salt heat storage energy release unit 10 mainly comprises a fused salt storage assembly, a heat exchange energy storage assembly and a heat exchange energy release assembly, wherein the fused salt storage assembly comprises a high-temperature fused salt storage tank 11 and a low-temperature fused salt storage tank 12, and the heat exchange energy storage assembly and the heat exchange energy release assembly are respectively connected with the high-temperature fused salt storage tank 11 and the low-temperature fused salt storage tank 12 through corresponding pipelines.

Specifically, the heat exchange energy storage component for connecting the high-temperature molten salt storage tank 11 and the low-temperature molten salt storage tank 12 comprises a flue gas heat exchange device 13 and a steam heat exchange device 14, and molten salt in the low-temperature molten salt storage tank 12 flows into the high-temperature molten salt storage tank 11 after being heated by the flue gas heat exchange device 13 and the steam heat exchange device 14 in sequence; the heat exchange energy release assembly for connecting the high-temperature molten salt storage tank 11 and the low-temperature molten salt storage tank 12 comprises a coal dust heating device 15 and a water supply heating device 16, and molten salt in the high-temperature molten salt storage tank 11 flows into the low-temperature molten salt storage tank 12 after being released by the coal dust heating device 15 and/or the water supply heating device 16.

The fused salt heat storage and energy release unit 10 can effectively utilize multi-grade energy through the flue gas heat exchange device 13 and the steam heat exchange device 14, can absorb low-temperature heat sources when the temperature is low, and can absorb high-temperature heat sources when the temperature is high; meanwhile, the fused salt heat storage and release unit 10 can realize the temperature opposite-mouth multi-way release according to different temperatures required by different parts, so that the energy or heat absorption and utilization efficiency is effectively improved. In addition, the device can heat the coal powder through the coal powder heating device 15, so that the combustion stability of the related boiler in low-load combustion is effectively improved.

Specifically, the above-mentioned flue gas heat transfer device 13 includes flue gas import, flue gas export, fused salt import and fused salt export, and wherein flue gas import and flue gas export are linked together, and fused salt import and fused salt export are linked together, and when high temperature flue gas passed this flue gas heat transfer device 13 through above-mentioned flue gas import and flue gas export, the fused salt that flows through this flue gas heat transfer device 13 can obtain the partial heat that high temperature flue gas carried to realize the effective utilization to the residual heat in the high temperature flue gas, reduce heat loss and waste, improve the utilization ratio of heat. Similarly, a steam inlet, a steam outlet, a fused salt inlet and a fused salt outlet are also arranged on the corresponding areas of the steam heat exchange device 14, and the fused salt passes through the steam heat exchange device 14 through the fused salt inlet and the fused salt outlet and stores energy in the process, as the flue gas heat exchange device 13.

Specifically, the above-mentioned pulverized coal heating device 15 includes pulverized coal inlet, pulverized coal outlet, molten salt inlet and molten salt outlet, wherein pulverized coal inlet and pulverized coal outlet are linked together, and molten salt inlet and molten salt outlet are linked together, when carrying the molten salt of certain heat through above-mentioned molten salt inlet and molten salt outlet and passing this pulverized coal heating device 15, the pulverized coal that flows through this pulverized coal heating device 15 can obtain the partial heat that the high temperature molten salt carried to realize the heating to the pulverized coal. The coal powder is heated, so that the temperature of the coal powder can be increased, the coal powder can be combusted more fully (the stability of the boiler can be improved in a low-load working condition operation through preheating the coal powder, the generation of harmful substances in smoke is reduced, and the variable load response rate of a unit is improved). Because the heat released by the fused salt is obtained from the corresponding boiler unit 21, the device can effectively utilize energy without affecting the normal operation of the boiler, and the energy waste is reduced. The structure and operation principle of the above-mentioned water supply heating device 16 are basically the same as those of the pulverized coal heating device 15, and will not be described here, wherein water in the water supply heating device 16 may be provided from outside the system.

It should be noted that, for safety, a switch bypass is disposed outside the above-mentioned pulverized coal heating device 15, and a valve structure for controlling on/off of a pipeline is correspondingly disposed at the upstream and downstream of the pulverized coal heating device 15, as shown in fig. 1. When the pulverized coal does not need to be heated, the high-temperature molten salt directly bypasses the switch to the water supply heating device 16.

In some embodiments, the heat exchange and energy storage assembly further comprises an electrical heating device 17 located between the steam heat exchange device 14 and the high temperature molten salt storage tank 11.

In order to further improve the energy storage effect of the molten salt, ensure that the obtained high-temperature molten salt can release enough heat to heat related water and steam when the load of a power grid is large, realize the rapid response function of the molten salt heat storage and release unit 10 when the peak of the system is regulated and the load is changed, and the electric heating device 17 is required to be arranged on the molten salt heat storage and release unit.

In some embodiments, a bypass 171 for circulating molten salt working medium is further arranged outside the electric heating device 17, and an on-off valve 172 is arranged on the bypass 171.

When the low-temperature molten salt reaches a set temperature after heat exchange and energy storage treatment by the flue gas heat exchange device 13 and the steam heat exchange device 14, an electric heater is not needed to heat the low-temperature molten salt. At this time, it is necessary to open the on-off valve 172 provided in the bypass 171, and the high-temperature molten salt may be circulated into the high-temperature molten salt tank 11 through the bypass 171.

Note that, a valve having an opening and closing function is correspondingly provided outside the electric heating device 17, as shown in fig. 1. When the molten salt temperature is sufficiently high or the electric heating device 17 fails, it is necessary to close the valve and open the on-off valve 172 located on the bypass 171.

In some embodiments, the steam heat exchanging device 14 includes a primary steam heat exchanger 141 and a secondary steam heat exchanger 142 arranged in sequence along the flow direction.

The above-mentioned second grade heat transfer structure arranges in proper order the mode and can realize carrying the effective utilization of heat to steam, as shown in fig. 2, high temperature steam flows through first order steam heat exchanger 141 and second grade steam heat exchanger 142 in proper order, in this process, the fused salt flows through second grade steam heat exchanger 142 and first order steam heat exchanger 141 in proper order to realize the secondary heating to the fused salt, wherein the lower fused salt of temperature carries out primary heating through the lower steam of temperature when flowing through second grade steam heat exchanger 142 after, flows into first grade steam heat exchanger 141 department again and carries out secondary heating through the higher steam of temperature. The secondary heating process can effectively improve the utilization rate of the fused salt to the heat carried by the steam.

Of course, it should be noted that a bypass 171 similar in structure to the external structure of the electric heating device 17 is also provided outside the steam heat exchanging device 14.

To power the flow of low temperature molten salt from the low temperature molten salt storage tank 12 into the high temperature molten salt storage tank 11, in some embodiments, the heat exchange and energy storage assembly further includes a low temperature molten salt pump 18. The low temperature molten salt pump 18 can power the flow of the low temperature molten salt.

When releasing the energy stored in the molten salt heat storage and release unit 10, the energy may be selected according to actual needs.

In order to increase the diversity of the released energy uses, in some embodiments, the heat exchange energy release assembly includes a first energy release branch and a second energy release branch, the pulverized coal heating device 15 is located on the first energy release branch, and the number of the feedwater heating devices 16 is at least two and is distributed on the first energy release branch and the second energy release branch respectively, as shown in fig. 1; after flowing into the first energy release branch and/or the second energy release branch, the molten salt in the high-temperature molten salt storage tank 11 merges and flows into the low-temperature molten salt storage tank 12.

Specifically, when only the first energy release branch is set to be in a communication state, the energy stored in the molten salt heat storage energy release unit 10 can be released through the pulverized coal heating device 15 and the partial water supply heating device 16, and the released energy is used for heating the pulverized coal and the partial water; when only the second energy release branch is set to be in a communication state, the energy stored in the molten salt heat storage and release unit 10 can be released by the partial water supply heating device 16.

The specific use and distribution of the feedwater heating device 16 is described below:

In some embodiments, as shown in fig. 1, the feedwater heating device 16 includes a molten salt feedwater medium temperature heat exchanger 161 located on a first energy release branch, and a molten salt feedwater superheater 162 and a molten salt feedwater evaporator 163 located on a second energy release branch, and the molten salt located in the high temperature molten salt storage tank 11 flows through the pulverized coal heating device 15 and the molten salt feedwater medium temperature heat exchanger 161 in sequence via the first energy release branch, and/or flows through the molten salt feedwater superheater 162 and the molten salt feedwater evaporator 163 in sequence via the second energy release branch, and then flows into the low temperature molten salt storage tank 12.

In some embodiments, a molten salt feed water low temperature heat exchanger 164 is further disposed on the second energy release branch, the molten salt feed water low temperature heat exchanger 164 is connected to the boiler unit 21, and condensed water is connected to the boiler unit 21 through the molten salt feed water low temperature heat exchanger 164.

The different feedwater heating devices 16 are different in the position and connection relationship, and therefore, the amount of available heat is different. In the embodiment, the opposite-mouth multi-way release of different temperatures can be realized by selecting and communicating different energy release branches, so that the cascade utilization of the molten salt energy is realized.

Whether the two different energy release branches are communicated or not can be adjusted according to the actual needs of the system. It should be noted that the two energy release branches are both provided with valves, and whether the molten salt is driven to flow can be controlled to release heat, the molten salt flow path, the distribution proportion and the like by controlling the opening and closing of the related valves.

In order to drive the high-temperature molten salt to flow from the high-temperature molten salt storage tank 11 to the low-temperature molten salt storage tank 12, in some embodiments, the heat exchange energy release assembly further comprises a high-temperature molten salt pump 19, and the molten salt in the high-temperature molten salt storage tank 11 flows into the low-temperature molten salt storage tank 12 through the coal dust heating device 15 and the water supply heating device 16 under the drive of the high-temperature molten salt pump 19.

It can be appreciated that the molten salt heat storage and release unit 10 provided in this embodiment has a plurality of different energy storage structures and energy release structures, so as to effectively utilize multi-grade heat sources. In addition, the device can heat the coal powder through the coal powder heating device 15, so that the combustion stability of the related boiler in low-load combustion is effectively improved.

The embodiment of the invention also provides a boiler unit depth peak shaving system, as shown in fig. 2. The deep peak regulation system of the boiler unit comprises a fused salt heat storage and energy release unit 10 and a boiler circulation unit 20, wherein the fused salt heat storage and energy release unit 10 is any fused salt heat storage and energy release unit 10; the boiler circulation unit 20 comprises a boiler unit 21, a steam turbine 22 and a condensate water recovery assembly 23 which are communicated with each other, wherein the boiler unit 21 is matched with a heat exchange energy storage assembly and a heat exchange energy release assembly in the molten salt heat storage energy release unit 10, the steam turbine 22 is matched with the heat exchange energy release assembly, and the condensate water recovery assembly 23 is matched with the steam turbine 22 and the heat exchange energy storage assembly.

Under the action of the fused salt heat storage and energy release unit 10, the energy released by the boiler circulation unit 20 in a partial stage can be effectively stored and conveyed to the boiler unit 21, the steam turbine 22 and the condensate water recovery assembly 23, so that the released energy can be recycled. The boiler unit deep peak regulation system can enable the boiler unit 21 to flexibly operate under a variable load working condition by applying the fused salt heat storage and energy release unit 10, meanwhile, the load response efficiency of a power grid in the process of switching from a normal section to a high peak section and a low load section is improved, the peak regulation depth of the unit is increased, and the system deep peak regulation system has important significance in improving the service level of a power system. In addition, the boiler unit deep peak regulation system further utilizes the fused salt heat storage energy release unit 10 to effectively improve the combustion stability of the boiler unit 21 in low load, and meanwhile, the heat utilization rate can be improved in a heat exchange mode when the power grid is in a high load period, so that the fused salt energy cascade utilization in energy release is realized, and compared with the existing energy storage system, the fused salt heat storage energy release system has better heat exchange efficiency, and can help to increase the generated energy of the steam turbine 22.

It should be noted that the above-described condensate recovery unit 23 may be used to recover condensate, and also to perform heat exchange by this recovery process to raise the temperature of water flowing back into the boiler unit 21, and may even be changed into steam carrying a certain amount of heat. The device can help reduce the air extraction of the turbine 22 during operation, thereby enabling more steam to be used for doing work to improve the power generation efficiency.

In some embodiments, the boiler unit 21 comprises a steam release assembly 211, a smoke exhaust assembly 212 and a coal inlet assembly 213, wherein the steam release assembly 211 is matched with the steam heat exchange device 14 in the heat exchange and energy storage assembly, the smoke exhaust assembly 212 is matched with the smoke heat exchange device 13, and the coal inlet assembly 213 is matched with the coal dust heating device 15; the steam turbine 22 comprises a high pressure cylinder 221, a middle pressure cylinder 222 and a low pressure cylinder 223 which are coaxially and sequentially arranged, and steam generated by the boiler unit 21 flows into the steam release assembly 211 and the high pressure cylinder 221 respectively; at least part of the water supply heating device 16 is connected with the medium pressure cylinder 222 through a pipeline, part of steam in the high pressure cylinder 221 and at least part of steam and/or liquid generated at the water supply heating device 16 flow into the medium pressure cylinder 222, and the low pressure cylinder 223 is connected with a generator and is used for driving the generator to generate electricity; the condensed water recovery assembly 23 comprises a steam heater 231, an air-cooled condenser 232, a condensed water pump 233, a deaerator 234 and a driving pump 235, wherein the number of the steam heater 231 is at least three, the high-pressure cylinder 221, the medium-pressure cylinder 222 and the low-pressure cylinder 223 are connected with at least one steam heater 231, the steam heat exchange device 14 is communicated with the deaerator 234 through a pipeline, and steam discharged by the steam heat exchange device 14 flows into the deaerator 234 through a pipeline; the condensed water generated at the air-cooled condenser 232 and the condensed water pump 233 is sequentially passed through the steam heater 231 and the deaerator 234 and is returned to the boiler unit 21 by the driving of the driving pump 235 group.

The boiler circulation unit 20 is used as follows:

Most of the steam generated during the operation of the boiler unit 21 enters a high pressure cylinder 221 of the steam turbine 22 to apply work, and the high pressure cylinder 221 comprises two stage groups, namely a first stage group and a second stage group. After entering the first stage group, the steam is divided into two parts, wherein one part enters the second stage group of the high pressure cylinder 221, and the other part serves as a steam source of the steam heater 231 corresponding to the first stage group as suction air. The steam entering the second stage group of the high pressure cylinder 221 is divided into two parts when discharged from the second stage group, wherein one part enters the superheater of the boiler unit 21 to be heated, and then the medium pressure high temperature steam is formed to enter the medium pressure cylinder 222 to apply work, and the other part of the steam is used as the steam source of the steam heater 231 corresponding to the second stage group as the suction air.

The superheater is a device for reheating working medium (i.e. steam) which has done work and has reduced temperature and pressure into high-temperature medium-pressure steam. As shown in fig. 2, the steam at the outlet of the high pressure cylinder 221 is fed into the boiler assembly for reheating treatment and then discharged into the medium pressure cylinder 222, except for a small portion used as suction.

The superheater is an important component for improving the heat efficiency of the boiler unit 21 and increasing the output.

The steam treated by the heater can be divided into two streams, wherein one stream enters the steam heat exchange device 14 of the fused salt heat storage and release unit 10, and the other stream enters the intermediate pressure cylinder 222 of the steam turbine 22. And the steam flowing into the medium pressure cylinder 222 is divided into two branches, one branch is the steam treated by the superheater, the other branch is the steam discharged from the molten salt water supply superheater 162 of the molten salt heat and energy storage and release unit 10, and the two branches are mixed and then enter the medium pressure cylinder 222. The intermediate pressure cylinder 222 includes three stage groups, a first stage group, a second stage group, and a third stage group, respectively. The steam entering the middle pressure cylinder 222 enters the corresponding steam heater 231 through the air suction in part after the first stage group treatment, and the other part enters the second stage group of the middle pressure cylinder 222. Steam in the second stage group of the medium pressure cylinder 222 enters the deaerator 234 after being pumped, and enters the small steam turbine 237 after being pumped, and the small steam turbine 237 can be used as a power source for driving the pre-pump 236 and the driving pump 235; the remaining steam enters the third stage group of intermediate pressure cylinders 222. At the third stage set outlet, some of the steam is pumped into the corresponding steam heater 231 and the remaining steam is fed into the low pressure cylinder 223. The low-pressure cylinder 223 also comprises three different stage groups, and after two times of pumping treatments consistent with the above process, pumping enters the steam heater 231 corresponding to the relevant stage group respectively, and exhaust steam enters the air-cooling condenser 232. The exhaust steam entering the air-cooling condenser 232 is condensed and then sequentially sent to the different steam heaters 231 and the deaerator 234 through the condensate pump 233, and sequentially flows through the other steam heaters 231 through the driving of the pre-pump 236, the driving pump 235 and the like, and forms steam after heat absorption treatment at each stage, finally flows into the boiler unit 21, and circulates the working process.

By controlling the opening and closing of the associated valves, the amount of steam entering the different pipes and in the different components can be varied.

In some embodiments, at least one drain is provided at the set of drive pumps 235, the drain being connected to the water inlet of the feedwater heating device 16.

Specifically, the outlet of the pre-pump 236 has two pipes, one of which is connected to the driving pump 235, and the other of which passes through a valve to form a drain C. The drain port C is divided into two branches and connected to the water side inlets of the molten salt water supply medium temperature heat exchanger 161 and the molten salt water supply evaporator 163, respectively. Similarly, the outlet of the driving pump 235 is also provided with two pipes, wherein the two pipes are always connected with the steam heater 231 corresponding to the first stage group of the medium pressure cylinder 222, and the other pipe forms a water outlet B which is connected with the water side inlet of the molten salt water feeding low temperature heat exchanger 164. The pipeline of the water side outlet of the molten salt feed water cryogenic heat exchanger 164 forms outlet a. The outlets of the steam heaters 231 corresponding to the first stage group of the above-described high pressure cylinders 221 can be merged with the outlet a and fed into the boiler unit 21.

Specifically, the pipeline of the water side outlet of the molten salt water feeding medium temperature heat exchanger 161 forms an outlet D, and the steam generated at the molten salt water feeding medium temperature heat exchanger 161 can be discharged to the third stage group of the intermediate pressure cylinder 222 of the steam turbine 22 through the outlet D and does work.

The following describes the working process of the boiler unit depth peak shaving system in the state that the molten salt heat storage and energy release unit 10 is in a heat storage state:

When the grid load is in the night off-peak period, the boiler circulation unit 20 is in a low load operating condition. Part of the reheat steam in the boiler unit 21 flows into the steam heat exchange device 14 through a valve in an air extraction mode, so that molten salt is heated, and part of the heat released steam is conveyed to the deaerator 234 through the valve and a pipeline. The molten salt flowing out from the outlet of the lower end of the low-temperature molten salt storage tank 12 enters the flue gas heat exchange device 13 through a valve and a corresponding pipeline to be preheated under the drive of a low-temperature facial pump, then flows through the corresponding valve, is sequentially treated by the secondary steam heat exchanger 142 and the primary steam heat exchanger 141, flows into the electric heating device 17 (namely an electric heater) to be further heated, and then flows into the high-temperature molten salt storage tank 11 through the valve and the pipeline through the inlet at the upper part to finish the heat storage of the low-temperature molten salt.

Under the lowest operation condition of the boiler circulation unit 20, the device can store heat of low-temperature molten salt under the condition of ensuring the highest efficiency, deep peak shaving of the level group is realized by a steam extraction and heat storage mode, the operation interval of the unit is enlarged, meanwhile, the stability of the boiler during low-load operation is improved by a coal powder preheating mode, the generation of harmful substances in smoke is reduced, and the variable load response rate of the unit is improved.

When the grid is in the flat period, the boiler cycle unit 20 is operating at normal load without peak shaving. At this time, it is not necessary to suck out the steam generated in the boiler unit 21 and heat the molten salt heat storage and release unit 10. Correspondingly, the outlet B and the outlet C are also in a closed state, at the moment, whether to perform fused salt heat storage operation or not can be determined according to fused salt grain storage in the high-temperature fused salt storage tank 11, so that enough high-temperature fused salt is ensured to heat steam and water when the power consumption peak power grid load is large, and quick response of the fused salt heat storage system in unit peak load regulation and load change is realized. If the heat storage requirement exists, the valve is directly used for controlling the low-temperature molten salt in the low-temperature molten salt storage tank 12 to directly heat through the flue gas heat exchange device 13 and the electric heating device 17, and the participation of the steam heat exchange device 14 is not needed.

The following describes the working process of the boiler unit deep peak shaving system in the exothermic state of the molten salt heat storage and release unit 10:

When the grid load is in the peak section, the boiler unit 21 in the boiler circulation unit 20 is in a high load operation state. At this time, the steam may be prevented from entering the molten salt heat storage and release unit 10 by closing the valve. Simultaneously, the high-temperature molten salt pump 19 is started, the coal dust heating device 15 and relevant valves and switch bypasses on the periphery of the coal dust heating device are closed (namely, the first energy release branch is closed, and the second energy release branch is opened), so that high-temperature molten salt sequentially flows through the molten salt water supply superheater 162, the molten salt water supply evaporator 163 and the molten salt water supply low-temperature heat exchanger 164 and releases heat, and finally flows into the low-temperature molten salt storage tank 12 through an upper inlet.

Part of the feed water from the drive pump 235 and the pre-pump 236 forms steam and enters the steam turbine 22 to do work so as to increase the power of the generator, and the rest of the feed water is mixed with the feed water heated by the steam heater 231 and enters the boiler unit 21 so as to reduce the extraction of the steam superheater, so that more steam is used for the work of the steam turbine 22.

When the grid load is in the night off-peak period, the boiler circulation unit 20 is in a low load operating condition. At this time, the high-temperature molten salt in the high-temperature molten salt storage tank 11 flows into the first energy release branch through the valve under the drive of the high-temperature molten salt pump 19, and preheats the pulverized coal through the pulverized coal heating device 15, so that the combustion stability of the hearth is improved, and at this time, the valve on the bypass outside the pulverized coal heating device 15 is in a closed state. The molten salt subjected to the preliminary heat exchange treatment flows into a molten salt water-supply medium-temperature heat exchanger 161 through a valve for further heat exchange, finally flows into a low-temperature molten salt storage tank 12 through the valve, and steam generated at the molten salt-water-supply medium-temperature heat exchanger enters a medium-pressure cylinder 222 for acting.

The heat absorption and heat release of the fused salt energy storage system is determined by the requirements of the boiler unit 21 in different periods of grid load, and is switched and adjusted with the electric auxiliary heating system through a pipeline valve.

It will be appreciated that the present invention forms a molten salt heat storage and release unit 10 by providing a plurality of heat storage and release structures having different temperature ranges. The boiler unit depth peak regulation system coupled with the fused salt heat storage and energy release unit 10 can enable the boiler circulation unit 20 to rapidly respond when the load is switched, improves the load response rate, increases the peak regulation depth of the unit, and improves the flexible operation capability of the unit. When the power grid is in a valley period, the fused salt heat storage and energy release unit 10 can be adjusted according to the power generation amount required by the power grid and the working condition characteristics of the boiler circulating unit 20, so that the power generation load of the boiler circulating unit 20 is reduced, and meanwhile, the stability of the pulverized coal during combustion is improved in a mode of preheating the pulverized coal; in the usual period, the low-temperature molten salt heating can be performed in modes of flue gas heat exchange, electric heating and the like according to requirements, so that the energy utilization rate is improved; in a high load state, superheated steam for the steam turbine 22 can be generated in a heat exchange mode to increase the generating capacity of the unit, and meanwhile, the generated condensed water is heated and supplied to the boiler unit 21, so that the air suction at the high-pressure cylinder 221 of the steam turbine 22 is reduced, and more steam is used for acting. The boiler unit depth peak shaving system provided by the embodiment has important significance for improving the service level of the power system.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (10)

1. A molten salt heat storage and release unit, comprising:

The molten salt storage assembly comprises a high-temperature molten salt storage tank (11) and a low-temperature molten salt storage tank (12);

The heat exchange energy storage assembly is connected with the high-temperature molten salt storage tank (11) and the low-temperature molten salt storage tank (12), and comprises a flue gas heat exchange device (13) and a steam heat exchange device (14), and molten salt in the low-temperature molten salt storage tank (12) flows into the high-temperature molten salt storage tank (11) after being heated by the flue gas heat exchange device (13) and the steam heat exchange device (14) in sequence;

The heat exchange energy release assembly is connected with the high-temperature molten salt storage tank (11) and the low-temperature molten salt storage tank (12), and comprises a coal dust heating device (15) and a water supply heating device (16), wherein molten salt in the high-temperature molten salt storage tank (11) flows into the low-temperature molten salt storage tank (12) after being released by the coal dust heating device (15) and/or the water supply heating device (16).

2. Molten salt heat and energy storage and release unit according to claim 1, characterized in that the heat exchange and energy storage assembly further comprises an electrical heating device (17) between the steam heat exchange device (14) and the high temperature molten salt storage tank (11);

And/or the steam heat exchange device (14) comprises a primary steam heat exchanger (141) and a secondary steam heat exchanger (142) which are sequentially arranged along the flow direction.

3. The molten salt heat storage and release unit according to claim 2, wherein a bypass (171) for circulating molten salt working medium is further arranged outside the electric heating device (17), and a switch valve (172) is arranged on the bypass (171).

4. The molten salt heat and energy storage and release unit according to claim 1, wherein the heat and energy exchange assembly comprises a first energy release branch and a second energy release branch, and molten salt in the high-temperature molten salt storage tank (11) is converged and flows into the low-temperature molten salt storage tank (12) after flowing into the first energy release branch and/or the second energy release branch;

The pulverized coal heating device (15) is located on the first energy release branch, and the number of the water supply heating devices (16) is at least two and is respectively distributed on the first energy release branch and the second energy release branch.

5. The molten salt heat and energy storage and release unit according to claim 4, wherein the feed water heating device (16) comprises a molten salt feed water intermediate temperature heat exchanger (161) positioned on the first energy release branch and a molten salt feed water superheater (162) and a molten salt feed water evaporator (163) positioned on the second energy release branch,

The molten salt in the high-temperature molten salt storage tank (11) sequentially flows through the pulverized coal heating device (15) and the molten salt water supply medium-temperature heat exchanger (161) through the first energy release branch, and/or sequentially flows through the molten salt water supply superheater (162) and the molten salt water supply evaporator (163) through the second energy release branch, and then flows into the low-temperature molten salt storage tank (12).

6. The molten salt heat and energy storage and release unit according to claim 4 or 5, wherein a molten salt water supply low-temperature heat exchanger (164) is further arranged on the second energy release branch, the molten salt water supply low-temperature heat exchanger (164) is connected with a boiler unit (21), and condensed water is connected with the boiler unit (21) through the molten salt water supply low-temperature heat exchanger (164).

7. The molten salt heat and energy storage and release unit according to claim 1, wherein the heat exchange and energy storage assembly further comprises a low-temperature molten salt pump (18), and molten salt in the low-temperature molten salt storage tank (12) flows into the high-temperature molten salt storage tank (11) through the flue gas heat exchange device (13) and the steam heat exchange device (14) under the driving of the low-temperature molten salt pump (18);

And/or the heat exchange energy release assembly further comprises a high-temperature molten salt pump (19), and molten salt in the high-temperature molten salt storage tank (11) flows into the low-temperature molten salt storage tank (12) through the coal dust heating device (15) and the water supply heating device (16) under the driving of the high-temperature molten salt pump (19).

8. A boiler unit depth peaking system, comprising:

A molten salt heat storage and release unit (10), wherein the molten salt heat storage and release unit (10) is a molten salt heat storage and release unit according to any one of claims 1 to 7;

The boiler circulation unit (20), boiler circulation unit (20) are including boiler unit (21), steam turbine (22) and the comdenstion water recovery subassembly (23) of intercommunication each other, boiler unit (21) with heat transfer energy storage subassembly with heat transfer energy release subassembly cooperatees, steam turbine (22) with heat transfer energy release subassembly cooperatees, comdenstion water recovery subassembly (23) with steam turbine (22) with heat transfer energy storage subassembly cooperatees.

9. The boiler unit depth peaking system according to claim 8, wherein the boiler unit (21) comprises a steam release assembly (211), a smoke exhaust assembly (212) and a coal inlet assembly (213), the steam release assembly (211) is matched with a steam heat exchange device (14) in the heat exchange and energy storage assembly, the smoke exhaust assembly (212) is matched with the flue gas heat exchange device (13), and the coal inlet assembly (213) is matched with the coal dust heating device (15);

The steam turbine (22) comprises a high-pressure cylinder (221), a middle-pressure cylinder (222) and a low-pressure cylinder (223) which are coaxially and sequentially arranged, and steam generated by the boiler unit (21) flows into the steam release assembly (211) and the high-pressure cylinder (221) respectively; at least part of the water supply heating device (16) is connected with the medium pressure cylinder (222) through a pipeline, and part of steam in the high pressure cylinder (221) and at least part of steam and/or liquid generated at the water supply heating device (16) flow into the medium pressure cylinder (222);

The condensate water recovery assembly (23) comprises a steam heater (231), an air-cooled condenser (232), a condensate water pump (233), a deaerator (234) and a driving pump (235), wherein the number of the steam heaters (231) is at least three, the high-pressure cylinder (221), the medium-pressure cylinder (222) and the low-pressure cylinder (223) are connected with at least one steam heater (231), the steam heat exchange device (14) is communicated with the deaerator (234) through a pipeline, and steam discharged by the steam heat exchange device (14) flows into the deaerator (234) through a pipeline; and under the drive of the drive pump (235), condensed water generated at the air-cooling condenser (232) and the condensed water pump (233) sequentially flows through the steam heater (231) and the deaerator (234) and flows back into the boiler unit (21).

10. The boiler unit depth peaking system of claim 9, wherein at least one drain is provided at the set of drive pumps (235), the drain being connected to the water inlet of the feedwater heating device (16).