Energy storage power generation system

Abstract

The present disclosure provides a kind of energy storage power generation system, comprising: boiler, including first heat exchange device;Turbine, including turbine body and second heat exchange device;And multiple molten salt circulation systems, between boiler and turbine body, configured to transmit the heat generated by boiler to the working medium of turbine body to make the working medium drive turbine body rotation, different molten salt circulation systems use different components of molten salt as heat exchange medium;Wherein, multiple molten salt circulation systems are thermally coupled with boiler by first heat exchange device, and molten salt absorbs heat from boiler by first heat exchange device, multiple molten salt circulation systems are thermally coupled with turbine body by second heat exchange device, and molten salt releases heat to the working medium of turbine body by second heat exchange device.The present disclosure can realize flexible operation of thermal power generating unit under different loads.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of coal-fired power generation, and in particular to an energy storage power generation system. BACKGROUND

[0002] With the implementation of China's new energy security strategy and new development concept, energy transformation is being further promoted, renewable energy generation is being connected to the grid on a large scale and continuously, and the proportion of renewable energy generation is increasing, and the utilization hours of thermal power generating units are declining. Due to the significant intermittency, volatility and randomness of renewable energy generation, the power system faces challenges such as low overall efficiency, insufficient coordination between sources, networks and loads, and insufficient complementary and mutual aid of various power sources. Based on the new pattern of energy supply and demand, the traditional peak shaving mechanism of thermal power generating units cannot meet the new requirements of power system flexibility on the power supply side. In order to realize the flexible operation of thermal power generating units under different loads, thereby increasing the proportion of renewable energy on the grid and reducing the phenomenon of curtailed wind and curtailed light, it has become an important development direction to build high-parameter and large-capacity thermal power generating units. SUMMARY

[0003] The purpose of the present disclosure is to provide an energy storage power generation system to realize the flexible operation of thermal power generating units under different loads.

[0004] The present disclosure provides an energy storage power generation system, comprising:

[0005] a boiler comprising a first heat exchange device;

[0006] a steam turbine comprising a steam turbine body and a second heat exchange device; and

[0007] a plurality of molten salt circulation systems arranged between the boiler and the steam turbine body and configured to transfer heat generated by the boiler to a working medium of the steam turbine body to drive the working medium to rotate the steam turbine body, different molten salt circulation systems using molten salt of different compositions as heat exchange medium;

[0008] wherein the plurality of molten salt circulation systems are thermally coupled to the boiler through the first heat exchange device, and the molten salt absorbs heat from the boiler through the first heat exchange device, and the plurality of molten salt circulation systems are thermally coupled to the steam turbine body through the second heat exchange device, and the molten salt releases heat to the working medium of the steam turbine body through the second heat exchange device.

[0009] According to some embodiments of the present disclosure, each of the molten salt circulation systems comprises a cold molten salt passage and a hot molten salt passage connected between the first heat exchange device and the second heat exchange device, the molten salt flows from the second heat exchange device to the first heat exchange device in the cold molten salt passage, and the molten salt flows from the first heat exchange device to the second heat exchange device in the hot molten salt passage,

[0010] The first heat exchange device comprises a plurality of first heat exchange units, and the inlet of the heated medium of each of the plurality of first heat exchange units is connected to the cold molten salt channel of the plurality of molten salt circulation systems one by one, and the outlet of the heated medium of each of the plurality of first heat exchange units is connected to the hot molten salt channel of the plurality of molten salt circulation systems one by one; and / or

[0011] The second heat exchange device comprises a plurality of second heat exchange units, and the inlet of the heating medium of each of the plurality of second heat exchange units is connected to the hot molten salt channel of the plurality of molten salt circulation systems one by one, and the outlet of the heating medium of each of the plurality of second heat exchange units is connected to the cold molten salt channel of the plurality of molten salt circulation systems one by one.

[0012] According to some embodiments of the present disclosure, each of the molten salt circulation systems comprises:

[0013] A cold molten salt storage device is arranged on the cold molten salt channel, the inlet of the cold molten salt storage device is connected to the outlet of the heating medium of the second heat exchange unit, and the outlet of the inlet of the cold molten salt storage device is connected to the inlet of the heated medium of the first heat exchange unit, and the cold molten salt storage device is configured to store the molten salt after releasing heat to the working medium of the steam turbine body;

[0014] A cold molten salt pumping device is arranged on the cold molten salt channel between the outlet of the cold molten salt storage device and the inlet of the heated medium of the first heat exchange unit, and the cold molten salt pumping device is configured to pump the molten salt from the cold molten salt storage device to the first heat exchange unit;

[0015] A hot molten salt storage device is arranged on the hot molten salt channel, the inlet of the hot molten salt storage device is connected to the outlet of the heated medium of the first heat exchange unit, and the outlet of the hot molten salt storage device is connected to the inlet of the heating medium of the second heat exchange unit, and the hot molten salt storage device is configured to store the molten salt after absorbing heat from the boiler; and

[0016] A hot molten salt pumping device is arranged on the hot molten salt channel between the outlet of the hot molten salt storage device and the inlet of the heating medium of the second heat exchange unit, and the hot molten salt pumping device is configured to pump the molten salt from the hot molten salt storage device to the second heat exchange unit.

[0017] According to some embodiments of the present disclosure,

[0018] The flow rate of the cold molten salt pumping device is adjustable; and / or

[0019] The flow rate of the hot molten salt pumping device is adjustable; and / or

[0020] Each of the molten salt circulation systems further comprises a cold molten salt valve disposed between the outlet of the cold molten salt storage device and the inlet of the heated medium of the first heat exchange section, the cold molten salt valve configured to regulate the flow rate of the molten salt pumped from the cold molten salt storage device to the first heat exchange section; and / or

[0021] Each of the molten salt circulation systems further comprises a hot molten salt valve disposed between the outlet of the hot molten salt storage device and the inlet of the heated medium of the second heat exchange section, the hot molten salt valve configured to regulate the flow rate of the molten salt pumped from the hot molten salt storage device to the second heat exchange section.

[0022] According to some embodiments of the present disclosure, each of the first heat exchange sections comprises a radiant section heat exchange section disposed at the radiant section of the boiler and a convection section heat exchange section disposed at the convection section of the boiler, the heated medium passage of the radiant section heat exchange section being in series with the heated medium passage of the convection section heat exchange section.

[0023] According to some embodiments of the present disclosure, the first heat exchange device further comprises a back pass heat exchange section disposed at the back pass of the boiler, the heated medium passage of the back pass heat exchange section being in series with the heated medium passage of the radiant section heat exchange section and the heated medium passage of the convection section heat exchange section.

[0024] According to some embodiments of the present disclosure, the plurality of molten salt circulation systems are thermally coupled with the steam turbine body through the second heat exchange device to heat the working fluid of the steam turbine body into main steam and / or at least one stage of reheated steam, wherein each stage of the reheated steam is heated by at least one of the plurality of second heat exchange sections.

[0025] According to some embodiments of the present disclosure, further comprising a working fluid supply system, the steam turbine body comprising a first cylinder and a second cylinder, each of the second heat exchange sections comprising:

[0026] a first working fluid heating device, the inlet of the heated medium of the first working fluid heating device being connected to the hot molten salt passage, the outlet of the heated medium of the first working fluid heating device being connected to the cold molten salt passage, the inlet of the heated medium of the first working fluid heating device being connected to the working fluid supply system, the outlet of the heated medium of the first working fluid heating device being connected to the steam inlet of the first cylinder, for heating the liquid working fluid provided by the working fluid supply system into main steam satisfying the working requirement of the first cylinder; and

[0027] a second working medium heating device, an inlet of a heating medium of the second working medium heating device being connected to the hot molten salt passage, an outlet of the heating medium of the second working medium heating device being connected to the cold molten salt passage, an inlet of a heated medium of the second working medium heating device being connected to the exhaust steam port of the first cylinder, an outlet of the heated medium of the second working medium heating device being connected to the inlet steam port of the second cylinder, for heating the cold reheat steam discharged from the first cylinder into reheat steam meeting the working requirement of the second cylinder.

[0028] According to some embodiments of the present disclosure, the first working medium heating device comprises a plurality of liquid working medium heaters arranged in series, the molten salt flows through the plurality of liquid working medium heaters in sequence to heat the liquid working medium provided by the working medium providing system, and the liquid working medium provided by the working medium providing system flows through the plurality of liquid working medium heaters in sequence in the order of the temperature of the molten salt from low to high.

[0029] According to some embodiments of the present disclosure, in the same second heat exchange part, the inlet of the heating medium of the second working medium heating device and the inlet of the heating medium of the liquid working medium heater with the highest temperature among the plurality of liquid working medium heaters are both connected to the hot molten salt passage, and the outlet of the heating medium of the second working medium heating device is connected to the inlet of the heating medium of the liquid working medium heater with the closest temperature.

[0030] According to some embodiments of the present disclosure,

[0031] The passages of the heated medium of the first working medium heating devices of different second heat exchange parts are connected in series, the liquid working medium provided by the working medium providing system sequentially passes through the first working medium heating devices of each second heat exchange part to form main steam meeting the working requirement of the first cylinder, and the liquid working medium provided by the working medium providing system flows through the first working medium heating devices of different second heat exchange parts in sequence in the order of the temperature of the molten salt from low to high; and / or

[0032] The passages of the heated medium of the second working medium heating devices of different second heat exchange parts are connected in series, the cold reheat steam discharged from the first cylinder sequentially passes through the second working medium heating devices of each second heat exchange part to form reheat steam meeting the working requirement of the second cylinder, and the cold reheat steam discharged from the first cylinder flows through the second working medium heating devices of different second heat exchange parts in sequence in the order of the temperature of the molten salt from low to high.

[0033] According to some embodiments of the present disclosure, the plurality of molten salt circulation systems comprises:

[0034] a first molten salt circulation system taking a first molten salt as a heat exchange medium; and

[0035] A second molten salt circulation system takes the second molten salt as the heat exchange medium.

[0036] The highest temperature of the first molten salt in a molten state is lower than the highest temperature of the second molten salt in a molten state.

[0037] According to some embodiments of the present disclosure,

[0038] The first molten salt comprises potassium nitrate with a content of 50% and sodium nitrate with a content of 50% by weight percentage; and / or

[0039] The second molten salt comprises sodium chloride with a content of 21%, barium chloride with a content of 31%, and calcium chloride with a content of 48% by weight percentage.

[0040] The energy storage power generation system provided by the embodiments of the present disclosure adopts molten salts with different compositions as heat exchange media. The working medium of the turbine body is heated and vaporized by the molten salts, which reduces the influence of boiler operation on the operation flexibility of the thermal power generating unit, helps to meet the new requirements of the power system for the flexibility of the power supply side, and improves the frequency modulation performance of the thermal power generating unit. Moreover, the molten salts with different compositions have different temperature ranges in a molten state, and the working medium of the turbine body is heated by molten salts with different temperature ranges, which helps to improve the steam parameters of the thermal power generating unit and improve the efficiency and capacity of the thermal power generating unit. The energy storage power generation system provided by the embodiments of the present disclosure helps to improve the consumption and absorption capacity of the power system for renewable energy power generation, supports large-scale renewable energy power generation and grid connection, reduces the phenomenon of abandoned wind and light, reduces resource waste, and relieves the peak regulation pressure of the power system, thereby providing protection for the safe and stable operation of the power system.

[0041] Other features of the present disclosure and its advantages will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0042] The drawings described herein are intended to provide further understanding of the present disclosure, and constitute a part of the present application. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute an improper limitation on the present disclosure. In the drawings:

[0043] Figure 1 A structural schematic diagram of the energy storage power generation system of some embodiments of the present disclosure.

[0044] Figure 2 A structural schematic diagram of the second heat exchange device of some embodiments of the present disclosure. DETAILED DESCRIPTION

[0045] With reference to the drawings and the embodiments of the present disclosure, the technical solutions in the embodiments of the present disclosure will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all the embodiments of the present disclosure. The description of the at least one example embodiment is merely illustrative in nature and does not limit the present disclosure and its application or uses in any way. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of the present disclosure.

[0046] The relative arrangement of components and steps, numerical expressions, and numerical values set forth in the embodiments are not intended to limit the scope of the present disclosure unless otherwise specifically stated. At the same time, it should be understood that the sizes of the various parts shown in the drawings are not drawn in accordance with the actual proportional relationship for the convenience of description. The techniques, methods and devices known to those skilled in the relevant art can not be discussed in detail, but in appropriate cases, these techniques, methods and devices should be considered as part of the authorized description. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, not as a limitation. Therefore, other examples of the example embodiments can have different values. It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0047] In the description of the present disclosure, it should be understood that the use of the words "first", "second", etc. to define parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present disclosure.

[0048] In the description of the present disclosure, it should be understood that the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present disclosure and simplifying the description, and in the absence of the opposite indication, these orientation words do not indicate and imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present disclosure; the orientation words "inner, outer" refer to the inner and outer relative to the contour of each component.

[0049] As Figure 1 and Figure 2As shown, some embodiments of the present disclosure provide an energy storage power generation system, which includes a boiler 1, a steam turbine, and a plurality of molten salt circulation systems. The boiler 1 includes a first heat exchange device 3. The steam turbine includes a steam turbine body 2 and a second heat exchange device 4. The plurality of molten salt circulation systems are arranged between the boiler 1 and the steam turbine body 2, and are configured to transfer heat generated by the boiler 1 to a working medium of the steam turbine body 2 to drive the working medium to rotate the steam turbine body 2. Different molten salt circulation systems adopt molten salts with different compositions as heat exchange media.

[0050] The plurality of molten salt circulation systems are thermally coupled with the boiler 1 through the first heat exchange device 3, and the molten salts absorb heat from the boiler 1 through the first heat exchange device 3. The plurality of molten salt circulation systems are thermally coupled with the steam turbine body 2 through the second heat exchange device 4, and the molten salts release heat to the working medium of the steam turbine body 2 through the second heat exchange device 4. After absorbing heat from the molten salts, the working medium changes from a liquid state to a gaseous state, and drives the blades of the steam turbine body 2 to work.

[0051] In the energy storage power generation system provided by the embodiments of the present disclosure, molten salts with different compositions are used as heat exchange media. The working medium of the steam turbine body is heated and vaporized by the molten salts, which reduces the influence of boiler operation on the operation flexibility of the thermal power generating unit, helps to meet the new requirements of the power system for the flexibility of the power supply side, and improves the frequency modulation performance of the thermal power generating unit. Moreover, molten salts with different compositions have different temperature ranges in the molten state, and the working medium of the steam turbine body uses molten salts with different temperature ranges, which helps to improve the steam parameters of the thermal power generating unit and improve the efficiency and capacity of the thermal power generating unit. The energy storage power generation system provided by the embodiments of the present disclosure helps to improve the consumption and absorption capacity of the power system for renewable energy power generation, supports large-scale renewable energy power generation and grid connection, reduces the phenomenon of curtailed wind power and curtailed solar power, reduces resource waste, and relieves the peak regulation pressure of the power system, thereby providing protection for the safe and stable operation of the power system.

[0052] In some embodiments, each molten salt circulation system includes a cold molten salt channel and a hot molten salt channel connected between the first heat exchange device 3 and the second heat exchange device 4. In the cold molten salt channel, the molten salt flows from the second heat exchange device 4 to the first heat exchange device 3. In the hot molten salt channel, the molten salt flows from the first heat exchange device 3 to the second heat exchange device 4.

[0053] The first heat exchange device 3 can include a plurality of first heat exchange parts. The inlets of the heated media of the plurality of first heat exchange parts are one-to-one connected to the cold molten salt channels of the plurality of molten salt circulation systems. The outlets of the heated media of the plurality of first heat exchange parts are one-to-one connected to the hot molten salt channels of the plurality of molten salt circulation systems.

[0054] The second heat exchange device 4 can include a plurality of second heat exchange units, the inlets of the heating medium of the plurality of second heat exchange units are connected to the hot molten salt channels of the plurality of molten salt circulation systems one by one, and the outlets of the heating medium of the plurality of second heat exchange units are connected to the cold molten salt channels of the plurality of molten salt circulation systems one by one.

[0055] In the above embodiment, the plurality of molten salt circulation systems correspond to the plurality of first heat exchange units one by one, and the plurality of molten salt circulation systems correspond to the plurality of second heat exchange units one by one. Different first heat exchange units corresponding to different molten salt circulation systems can be independently arranged at different positions of the boiler according to the temperature range of the molten salt in the molten state, which is beneficial to fully utilize the heat generated in the boiler. The different second heat exchange units corresponding to the different molten salt circulation systems can multi-stage heat the working medium, which is beneficial to improve the steam parameters of the working medium.

[0056] In some embodiments, each molten salt circulation system includes a cold molten salt storage device, a cold molten salt pumping device, a hot molten salt storage device, and a hot molten salt pumping device.

[0057] The cold molten salt storage device is arranged on the cold molten salt channel, the inlet of the cold molten salt storage device is connected to the outlet of the heating medium of the second heat exchange unit, and the outlet of the inlet of the cold molten salt storage device is connected to the inlet of the heated medium of the first heat exchange unit, and is configured to store the molten salt after releasing heat to the working medium of the turbine body 2.

[0058] The cold molten salt pumping device is arranged on the cold molten salt channel between the outlet of the cold molten salt storage device and the inlet of the heated medium of the first heat exchange unit, and is configured to pump the molten salt from the cold molten salt storage device to the first heat exchange unit.

[0059] The hot molten salt storage device is arranged on the hot molten salt channel, the inlet of the hot molten salt storage device is connected to the outlet of the heated medium of the first heat exchange unit, and the outlet of the hot molten salt storage device is connected to the inlet of the heating medium of the second heat exchange unit, and is configured to store the molten salt after absorbing heat from the boiler 1.

[0060] The hot molten salt pumping device is arranged on the hot molten salt channel between the outlet of the hot molten salt storage device and the inlet of the heating medium of the second heat exchange unit, and is configured to pump the molten salt from the hot molten salt storage device to the second heat exchange unit.

[0061] When the energy storage power generation system is in operation, the load of the boiler is substantially stable, and the load of the steam turbine varies with the load of the power system. In order to respond to the change of the load of the steam turbine, the flow rate of the molten salt in the cold molten salt channel and the hot molten salt channel should be adjustable. In some embodiments, the adjustment of the flow rate of the molten salt can be achieved by one or more of the following means: the flow rate of the cold molten salt pumping device is adjustable; the flow rate of the hot molten salt pumping device is adjustable; each molten salt circulation system further comprises a cold molten salt valve arranged between the outlet of the cold molten salt storage device and the inlet of the heated medium of the first heat exchange part, and the cold molten salt valve is configured to adjust the flow rate of the molten salt pumped from the cold molten salt storage device to the first heat exchange part; each molten salt circulation system further comprises a hot molten salt valve arranged between the outlet of the hot molten salt storage device and the inlet of the heated medium of the second heat exchange part, and the hot molten salt valve is configured to adjust the flow rate of the molten salt pumped from the hot molten salt storage device to the second heat exchange part.

[0062] In the above embodiments, by adjusting the flow rate of the molten salt in the cold molten salt channel and the hot molten salt channel, the flow rate of the molten salt provided by the hot molten salt storage device to the second heat exchange device 4 can be less than, equal to or greater than the flow rate of the molten salt provided by the first heat exchange device 3 to the hot molten salt storage device, thereby achieving the adjustment of the load of the steam turbine. According to the change of the flow rate of the molten salt provided by the hot molten salt storage device to the second heat exchange device 4, the load of the steam turbine can be adjusted in a range from zero load to full load, and the steam turbine is in a hot standby state when the load is adjusted to zero.

[0063] In some embodiments, each first heat exchange part comprises a radiant section heat exchange part arranged in the radiant section of the boiler 1 and a convection section heat exchange part arranged in the convection section of the boiler 1, and the heated medium channel of the radiant section heat exchange part is in series with the heated medium channel of the convection section heat exchange part. The molten salt from the cold molten salt channel can directly flow into the radiant section heat exchange part and the convection section heat exchange part to absorb heat from the flue gas in the boiler 1.

[0064] On the basis of arranging the radiant section heat exchange part and the convection section heat exchange part, in order to make more full use of the heat generated by the boiler 1, in some embodiments, the first heat exchange device 3 further comprises a back pass heat exchange part arranged in the back pass of the boiler 1, and the heated medium channel of the back pass heat exchange part is in series with the heated medium channel of the radiant section heat exchange part and the heated medium channel of the convection section heat exchange part. By arranging the back pass heat exchange part, the molten salt from the cold molten salt channel can be preheated by flowing into the back pass heat exchange part first, and then flows into the radiant section heat exchange part and the convection section heat exchange part to further absorb heat from the flue gas in the boiler 1.

[0065] In some embodiments, the plurality of molten salt circulation systems are thermally coupled to the steam turbine body 2 through the second heat exchange device 4 to heat the working medium of the steam turbine body 2 to main steam and / or at least one stage of reheated steam, wherein each stage of reheated steam is heated by at least one of the plurality of second heat exchange parts.

[0066] As Figure 1 and Figure 2 shown, in some embodiments, the energy storage power generation system further comprises a working fluid providing system for providing liquid working fluid to the steam turbine. The liquid working fluid can be water or an organic working fluid. The steam turbine body 2 comprises a first cylinder 21 and a second cylinder 22. Each second heat exchange part comprises a first working fluid heating device and a second working fluid heating device.

[0067] The inlet of the heating medium of the first working fluid heating device is connected to the hot molten salt channel, the outlet of the heating medium of the first working fluid heating device is connected to the cold molten salt channel, the inlet of the heated medium of the first working fluid heating device is connected to the working fluid providing system, and the outlet of the heated medium of the first working fluid heating device is connected to the steam inlet of the first cylinder 21, for heating the liquid working fluid provided by the working fluid providing system into main steam meeting the working requirement of the first cylinder 21.

[0068] The inlet of the heating medium of the second working fluid heating device is connected to the hot molten salt channel, the outlet of the heating medium of the second working fluid heating device is connected to the cold molten salt channel, the inlet of the heated medium of the second working fluid heating device is connected to the steam exhaust of the first cylinder 21, and the outlet of the heated medium of the second working fluid heating device is connected to the steam inlet of the second cylinder 22, for heating the cold reheat steam exhausted by the first cylinder 21 into reheat steam meeting the working requirement of the second cylinder 22.

[0069] The arrangement of the first working fluid heating device and the second working fluid heating device can realize the reheat cycle of the working fluid of the steam turbine body 2, which is conducive to improving the efficiency of the thermal power generating unit and reducing the carbon dioxide emission. In some embodiments, the efficiency of the thermal power generating unit can exceed 50%.

[0070] In the above embodiments, the second heat exchange device 4 can heat the working fluid into main steam and first-stage reheat steam.

[0071] In some embodiments not shown in the figure, the steam turbine body 2 can further comprise more cylinders, or each cylinder can comprise more steam inlets and steam exhausts, and the second heat exchange part can further comprise more working fluid heating devices for heating the working fluid into main steam and multi-stage reheat steam.

[0072] For example, the second heat exchange part further comprises a third working fluid heating device, the inlet of the heating medium of the third working fluid heating device is connected to the hot molten salt channel, the outlet of the heating medium of the third working fluid heating device is connected to the cold molten salt channel, the inlet of the heated medium of the third working fluid heating device is connected to the steam exhaust of the second cylinder, and the outlet of the heated medium of the third working fluid heating device is connected to the steam inlet of a third cylinder, for heating the cold reheat steam exhausted by the second cylinder into reheat steam meeting the working requirement of the third cylinder.

[0073] The above arrangement can realize multiple reheats of the cold reheat steam, thereby improving the efficiency of the thermal power unit.

[0074] In order to make the liquid working medium sufficiently absorb the heat of the molten salt to improve the steam parameters such as the temperature and pressure of the main steam, in some embodiments, the first working medium heating device comprises a plurality of liquid working medium heaters arranged in series, the molten salt flows through the plurality of liquid working medium heaters in sequence to heat the liquid working medium provided by the working medium providing system, the liquid working medium provided by the working medium providing system flows through the plurality of liquid working medium heaters in sequence in the order of the temperature of the molten salt from low to high, and the liquid working medium and the molten salt counterflow heat exchange.

[0075] In some embodiments, in the same second heat exchange part, the inlet of the heating medium of the second working medium heating device and the inlet of the heating medium of the one of the plurality of liquid working medium heaters with the highest temperature are connected to the hot molten salt channel, and the outlet of the heating medium of the second working medium heating device is connected to the inlet of the heating medium of the one of the plurality of liquid working medium heaters with the closest temperature. The molten salt is divided into two parts after entering the second heat exchange part from the hot molten salt channel, the first part of the molten salt is used to heat the liquid working medium, and the second part of the molten salt is used to heat the cold reheat steam. The second part of the molten salt is combined with the first part of the molten salt after heating the cold reheat steam, which is beneficial to fully utilize the waste heat of the molten salt and reduce energy loss.

[0076] In some embodiments, the channels of the heated medium of the first working medium heating devices of different second heat exchange parts are connected in series, and the liquid working medium provided by the working medium providing system sequentially passes through the first working medium heating devices of the second heat exchange parts to form the main steam meeting the working requirement of the first cylinder 21. The liquid working medium provided by the working medium providing system sequentially flows through the first working medium heating devices of the different second heat exchange parts in the order of the temperature of the molten salt from low to high, and the liquid working medium and the molten salt counterflow heat exchange.

[0077] In some embodiments, the channels of the heated medium of the second working medium heating devices of different second heat exchange parts are connected in series, and the cold reheat steam discharged from the first cylinder 21 sequentially passes through the second working medium heating devices of the second heat exchange parts to form the reheated steam meeting the working requirement of the second cylinder 22. The cold reheat steam discharged from the first cylinder 21 sequentially flows through the second working medium heating devices of the different second heat exchange parts in the order of the temperature of the molten salt from low to high, and the cold reheat steam and the molten salt counterflow heat exchange.

[0078] In the above embodiments, the liquid working medium and the cold reheat steam are sequentially subjected to multi-stage heating of the molten salt with different temperature intervals. By using the molten salt with a higher temperature in the molten state, the steam parameters such as the main steam pressure, the main steam temperature, the reheated steam pressure, and the reheated steam temperature of the thermal power unit can be further improved.

[0079] As Figure 1As shown, in some embodiments, the multiple molten salt circulation systems include a first molten salt circulation system and a second molten salt circulation system. The first molten salt circulation system uses a first molten salt as the heat exchange medium, and the second molten salt circulation system uses a second molten salt as the heat exchange medium. The highest temperature of the first molten salt in the molten state is lower than the highest temperature of the second molten salt in the molten state.

[0080] In the above embodiments, the first molten salt may include 50% potassium nitrate and 50% sodium nitrate, by weight percentage. The temperature range of the first molten salt is 260℃ to 550℃.

[0081] In the above embodiments, the second molten salt may include 21% sodium chloride, 31% barium chloride, and 48% calcium chloride, by weight percentage. The temperature range of the second molten salt is 480℃ to 750℃.

[0082] The following is combined Figure 1 and Figure 2 The energy storage power generation system of some embodiments of this disclosure will be further described. For components not described in the energy storage power generation system, their functions, and the positional relationships between components, please refer to the foregoing descriptions.

[0083] like Figure 1 As shown, the energy storage power generation system includes a boiler 1, a steam turbine, a first molten salt circulation system, a second molten salt circulation system, and a generator 7. The first molten salt circulation system uses first molten salt as the heat exchange medium, and the second molten salt circulation system uses second molten salt as the heat exchange medium.

[0084] Boiler 1 includes a first heat exchange device 3. A first molten salt circulation system and a second molten salt circulation system are thermally coupled to boiler 1 through the first heat exchange device 3.

[0085] The first heat exchange device 3 includes a first furnace-internal heat exchange section 31A and a first tail flue heat exchange section 32A, whose heated medium channels are connected in series, and a second furnace-internal heat exchange section 31B and a second tail flue heat exchange section 32B, whose heated medium channels are connected in series. The first furnace-internal heat exchange section 31A includes a first radiant section heat exchange section and a first convection section heat exchange section, and the second furnace-internal heat exchange section 32B includes a second radiant section heat exchange section and a second convection section heat exchange section. The inlet of the heated medium in the first tail flue heat exchange section 32A is connected to the cold molten salt channel of the first molten salt circulation system, and the outlet of the heated medium in the first furnace-internal heat exchange section 31A is connected to the hot molten salt channel of the first molten salt circulation system. The inlet of the heated medium in the second tail flue heat exchange section 32B is connected to the cold molten salt channel of the second molten salt circulation system, and the outlet of the heated medium in the second furnace-internal heat exchange section 31B is connected to the hot molten salt channel of the second molten salt circulation system.

[0086] The steam turbine comprises a steam turbine body 2 and a second heat exchange device 4. The steam turbine body 2 is drivingly connected with a generator 7. The steam turbine body 2 comprises a first cylinder 21 and a second cylinder 22. The first molten salt circulation system and the second molten salt circulation system are thermally coupled with the steam turbine body 2 through the second heat exchange device 4. The second heat exchange device 4 comprises a first first working medium heating device, a first second working medium heating device, a second first working medium heating device and a second second working medium heating device.

[0087] The first first working medium heating device comprises a first heater 41A, a second heater 42A and a third heater 43A, the heating medium channels of the first heater 41A, the second heater 42A and the third heater 43A are sequentially connected in series, and the heated medium channels of the first heater 41A, the second heater 42A and the third heater 43A are sequentially connected in series. The first second working medium heating device comprises a fourth heater 40A.

[0088] The inlet of the heating medium of the first heater 41A is connected with the hot molten salt channel of the first molten salt circulation system, the outlet of the heating medium of the third heater 43A is connected with the cold molten salt channel of the first molten salt circulation system, the inlet of the heating medium of the fourth heater 40A is connected with the hot molten salt channel of the first molten salt circulation system, and the outlet of the heating medium of the fourth heater 40A is connected with the inlet of the heating medium of the second heater 42A.

[0089] The second first working medium heating device comprises a fifth heater 41B, a sixth heater 42B and a seventh heater 43B. The heating medium channels of the fifth heater 41B, the sixth heater 42B and the seventh heater 43B are sequentially connected in series, and the heated medium channels of the fifth heater 41B, the sixth heater 42B and the seventh heater 43B are sequentially connected in series. The second second working medium heating device comprises an eighth heater 40B.

[0090] The inlet of the heating medium of the fifth heater 41B is connected with the hot molten salt channel of the second molten salt circulation system, the outlet of the heating medium of the seventh heater 43B is connected with the cold molten salt channel of the second molten salt circulation system, the inlet of the heating medium of the eighth heater 40B is connected with the hot molten salt channel of the second molten salt circulation system, and the outlet of the heating medium of the eighth heater 40B is connected with the inlet of the heating medium of the sixth heater 42B.

[0091] The inlet of the heated medium of the third heater 43A is connected with the working medium providing system, the outlet of the heated medium of the first heater 41A is connected with the inlet of the heated medium of the seventh heater 43B, and the outlet of the heated medium of the fifth heater 41B is connected with the steam inlet of the first cylinder 21. The inlet of the heated medium of the fourth heater 44A is connected with the steam outlet of the first cylinder 21, the outlet of the heated medium of the fourth heater 44A is connected with the inlet of the heated medium of the eighth heater 44B, and the outlet of the heated medium of the eighth heater 44B is connected with the steam inlet of the second cylinder 22.

[0092] The first molten salt circulation system comprises a first cold molten salt storage device 51, a first cold molten salt pumping device 52, a first hot molten salt storage device 53 and a first hot molten salt pumping device 54. The first cold molten salt storage device 51 is arranged on the cold molten salt passage of the first molten salt circulation system, and the first cold molten salt pumping device 52 is arranged on the cold molten salt passage between the inlet of the heated medium of the first tail flue heat exchange part 32A and the outlet of the first cold molten salt storage device 51 and is adjustable in flow rate. The first hot molten salt storage device 53 is arranged on the hot molten salt passage of the first molten salt circulation system, and the first hot molten salt pumping device 54 is arranged on the hot molten salt passage between the outlet of the heated medium of the first in-furnace heat exchange part 31A and the inlet of the first hot molten salt storage device 53 and is adjustable in flow rate.

[0093] The second molten salt circulation system comprises a second cold molten salt storage device 61, a second cold molten salt pumping device 62, a second hot molten salt storage device 63 and a second hot molten salt pumping device 64. The second cold molten salt storage device 61 is arranged on the cold molten salt passage of the second molten salt circulation system, and the second cold molten salt pumping device 62 is arranged on the cold molten salt passage between the inlet of the heated medium of the second tail flue heat exchange part 32B and the outlet of the second cold molten salt storage device 61 and is adjustable in flow rate. The second hot molten salt storage device 63 is arranged on the hot molten salt passage of the second molten salt circulation system, and the second hot molten salt pumping device 64 is arranged on the hot molten salt passage between the outlet of the heated medium of the second in-furnace heat exchange part 31B and the inlet of the second hot molten salt storage device 63 and is adjustable in flow rate.

[0094] The working process of the energy storage power generation system is as follows.

[0095] In the first molten salt circulation system, the cold first molten salt stored in the first cold molten salt storage device 51 is preheated by entering the first tail flue heat exchange part 32A under the pumping of the first cold molten salt pumping device 52, and then enters the first in-furnace heat exchange part 31A, and is heated by the flue gas in the boiler 1 to become hot first molten salt, and is stored in the first hot molten salt storage device 53, thereby completing the heat absorption process from the boiler 1; the hot first molten salt stored in the first hot molten salt storage device 53 is pumped by the first hot molten salt pumping device 54, and enters the first heat exchanger 41A and the fourth heat exchanger 40A respectively to heat the liquid working medium provided by the working medium providing system and the cold reheat steam provided by the exhaust port of the first cylinder 21 respectively, and after the mixing of the first molten salt in the first heat exchanger 41A and the fourth heat exchanger 40A, the first molten salt enters the second heater 42A and the third heater 43A to heat the liquid working medium provided by the working medium providing system, thereby completing the heat release process to the working medium of the steam turbine body 2, and after the heat release, the cold first molten salt is stored in the first cold molten salt storage device 51.

[0096] In the second molten salt circulation system, the cold second molten salt stored in the second cold molten salt storage device 61 is preheated by entering the second tail flue heat exchange part 32B under the pumping of the second cold molten salt pumping device 62, and then enters the second in-furnace heat exchange part 31B, and is heated by the flue gas in the boiler 1 to become hot second molten salt, and is stored in the second hot molten salt storage device 63, thereby completing the heat absorption process from the boiler 1; the hot second molten salt stored in the second hot molten salt storage device 63 is pumped by the second hot molten salt pumping device 64, and enters the fifth heat exchanger 41B and the eighth heat exchanger 40B respectively to heat the liquid working medium provided by the working medium providing system and the cold reheat steam provided by the exhaust port of the first cylinder 21 respectively, and after the mixing of the second molten salt in the fifth heat exchanger 41B and the eighth heat exchanger 40B, the second molten salt enters the sixth heater 42B and the seventh heater 43B to heat the liquid working medium provided by the working medium providing system, thereby completing the heat release process to the working medium of the steam turbine body 2, and after the heat release, the cold second molten salt is stored in the second cold molten salt storage device 61.

[0097] The liquid working medium provided by the working medium providing system is sequentially passed through the third heat exchanger 43A, the second heat exchanger 42A, the first heat exchanger 41A, the seventh heat exchanger 43B, the sixth heat exchanger 42B and the fifth heat exchanger 41B, and is heated into main steam meeting the working requirement of the first cylinder 21. After the main steam works in the first cylinder 21, it becomes cold reheat steam and is discharged from the exhaust port of the first cylinder 21. The cold reheat steam discharged from the exhaust port of the first cylinder 21 is sequentially passed through the fourth heat exchanger 40A and the eighth heat exchanger 40B, and is heated into reheat steam meeting the working requirement of the second cylinder 22. After the reheat steam works in the second cylinder 22, it is discharged from the exhaust port of the second cylinder 22, and after being heated by the condenser of the steam turbine and the regenerative system of the steam turbine, it reenters the second heat exchange device 4 to complete the working cycle.

[0098] The energy storage power generation system adjusts the flow rates of the first molten salt and the second molten salt by adjusting the flow rates of the first hot molten salt pumping device 54 and the second hot molten salt pumping device 64, so as to respond to the change of the load of the steam turbine and meet the steam demand of the steam turbine.

[0099] When the load of the steam turbine is equal to the load of the boiler, the heat generated by the boiler 1 is equal to the heat required for the working medium of the steam turbine body 1 to drive the steam turbine body 2 to rotate, the flow rate of the first molten salt provided by the first hot molten salt storage device 53 to the second heat exchange device 4 is equal to the flow rate of the first molten salt provided by the first heat exchange device 3 to the first hot molten salt storage device 53, and the flow rate of the second molten salt provided by the second hot molten salt storage device 63 to the second heat exchange device 4 is equal to the flow rate of the second molten salt provided by the first heat exchange device 3 to the second hot molten salt storage device 63.

[0100] When the load of the steam turbine is lower than the load of the boiler, that is, when the steam turbine operates at a lower load, the heat generated by the boiler 1 is greater than the heat required for the working medium of the steam turbine body 2 to drive the steam turbine body 2 to rotate, at this time, by adjusting the flow rates of the first cold molten salt pumping device 52, the second cold molten salt pumping device 62, the first hot molten salt pumping device 54 and the second hot molten salt pumping device 64, the flow rate of the first molten salt provided by the first hot molten salt storage device 53 to the second heat exchange device 4 is less than the flow rate of the first molten salt provided by the first heat exchange device 3 to the first hot molten salt storage device 53, the flow rate of the second molten salt provided by the second hot molten salt storage device 63 to the second heat exchange device 4 is less than the flow rate of the second molten salt provided by the first heat exchange device 3 to the second hot molten salt storage device 63, and the surplus part of the heat generated by the boiler 1 is stored in the first hot molten salt storage device 53 and the second hot molten salt storage device 54 with the first molten salt and the second molten salt, and the energy storage power generation system stores energy.

[0101] When the steam turbine load is higher than the boiler load, i.e. the steam turbine is running at a higher load, the heat generated by the boiler 1 is less than the heat required by the working medium of the steam turbine body 2 to drive the steam turbine body 2 to rotate, at this time, by adjusting the flow of the first cold molten salt pumping device 52, the second cold molten salt pumping device 62, the first hot molten salt pumping device 54 and the second hot molten salt pumping device 64, the flow of the first molten salt provided by the first hot molten salt storage device 53 to the second heat exchange device 4 is greater than the flow of the first molten salt provided by the first heat exchange device 3 to the first hot molten salt storage device 53, and the flow of the second molten salt provided by the second hot molten salt storage device 63 to the second heat exchange device 4 is greater than the flow of the second molten salt provided by the first heat exchange device 3 to the second hot molten salt storage device 63, and the insufficient part of the heat required by the working medium of the steam turbine body 2 to drive the steam turbine body 2 to rotate is provided by the first molten salt and the second molten salt stored in the first hot molten salt storage device 53 and the second hot molten salt storage device 54, and the energy storage power generation system releases energy.

[0102] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present disclosure, but not to limit it; although the present disclosure has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the specific embodiments of the present disclosure can be modified or some technical features can be replaced by equivalent ones, which should be covered in the technical solution range of the present disclosure.

Claims

1. An energy storage power generation system, characterized in that, include: Boiler (1), including first heat exchange device (3); A steam turbine, including a steam turbine body (2) and a second heat exchange device (4); and Multiple molten salt circulation systems are set between the boiler (1) and the turbine body (2) and are configured to transfer the heat generated by the boiler (1) to the working medium of the turbine body (2) so that the working medium drives the turbine body (2) to rotate. Different molten salt circulation systems use molten salt with different compositions as heat exchange medium. The plurality of molten salt circulation systems are thermally coupled to the boiler (1) through the first heat exchange device (3), the molten salt absorbs heat from the boiler (1) through the first heat exchange device (3), the plurality of molten salt circulation systems are thermally coupled to the turbine body (2) through the second heat exchange device (4), and the molten salt releases heat to the working fluid of the turbine body (2) through the second heat exchange device (4); Each of the molten salt circulation systems includes a cold molten salt channel and a hot molten salt channel connected between the first heat exchange device (3) and the second heat exchange device (4). In the cold molten salt channel, the molten salt flows from the second heat exchange device (4) to the first heat exchange device (3), and in the hot molten salt channel, the molten salt flows from the first heat exchange device (3) to the second heat exchange device (4). The first heat exchange device (3) includes a plurality of first heat exchange sections. The inlets of the heated media of the plurality of first heat exchange sections are connected one-to-one to the cold molten salt channels of the plurality of molten salt circulation systems, and the outlets of the heated media of the plurality of first heat exchange sections are connected one-to-one to the hot molten salt channels of the plurality of molten salt circulation systems. The second heat exchange device (4) includes a plurality of second heat exchange sections. The inlets of the heated media of the plurality of second heat exchange sections are connected one-to-one to the hot molten salt channels of the plurality of molten salt circulation systems, and the outlets of the heated media of the plurality of second heat exchange sections are connected one-to-one to the cold molten salt channels of the plurality of molten salt circulation systems. The plurality of molten salt circulation systems are thermally coupled to the turbine body (2) through the second heat exchange device (4) to heat the working fluid of the turbine body (2) into main steam and / or at least one stage of reheat steam, wherein each stage of reheat steam is heated by at least one of the plurality of second heat exchange units; The energy storage power generation system also includes a working fluid supply system. The turbine body (2) includes a first cylinder (21) and a second cylinder (22). Each second heat exchange section includes a first working fluid heating device and / or a second working fluid heating device. The inlet of the heating medium of the first working fluid heating device is connected to the hot molten salt channel, and the outlet of the heating medium of the first working fluid heating device is connected to the cold molten salt channel. The inlet of the heated medium of the first working fluid heating device is connected to the working fluid supply system, and the outlet of the heated medium of the first working fluid heating device is connected to the steam inlet of the first cylinder (21), for use in heating the working fluid. The working fluid supply system provides liquid working fluid heating to meet the working requirements of the first cylinder (21) as main steam. The inlet of the heating medium of the second working fluid heating device is connected to the hot molten salt channel, the outlet of the heating medium of the second working fluid heating device is connected to the cold molten salt channel, the inlet of the heated medium of the second working fluid heating device is connected to the exhaust port of the first cylinder (21), and the outlet of the heated medium of the second working fluid heating device is connected to the inlet of the second cylinder (22). This is used to heat the cold reheat steam discharged from the first cylinder (21) into reheat steam that meets the working requirements of the second cylinder (22). The channels of the heated medium of the first working medium heating device of different second heat exchange sections are connected in series. The liquid working medium provided by the working medium supply system passes through the first working medium heating device of each second heat exchange section in sequence to form the main steam that meets the working requirements of the first cylinder (21). The liquid working medium provided by the working medium supply system flows through the first working medium heating device of different second heat exchange sections in sequence according to the temperature of the molten salt from low to high. And / or, the channels of the heated medium of the second working medium heating device of different second heat exchange sections are connected in series. The cold reheat steam discharged from the first cylinder (21) passes through the second working medium heating device of each second heat exchange section in sequence to form the reheat steam that meets the working requirements of the second cylinder (22). The cold reheat steam discharged from the first cylinder (21) flows through the second working medium heating device of different second heat exchange sections in sequence according to the temperature of the molten salt from low to high. Each of the first heat exchange sections includes a radiant section heat exchange section disposed in the radiant section of the boiler (1) and a convection section heat exchange section disposed in the convection section of the boiler (1), wherein the channel of the heated medium in the radiant section heat exchange section is connected in series with the channel of the heated medium in the convection section heat exchange section.

2. The energy storage power generation system according to claim 1, characterized in that, Each of the molten salt circulation systems includes: A molten salt storage device is provided on the molten salt channel. The inlet of the molten salt storage device is connected to the outlet of the heating medium of the second heat exchange section, and the outlet of the inlet of the molten salt storage device is connected to the inlet of the heated medium of the first heat exchange section. It is configured to store the molten salt after releasing heat to the working medium of the turbine body (2). A molten salt pumping device is disposed on the molten salt channel between the outlet of the molten salt storage device and the inlet of the heated medium of the first heat exchange section, and is configured to pump the molten salt from the molten salt storage device to the first heat exchange section. A molten salt storage device is disposed on the molten salt channel. The inlet of the molten salt storage device is connected to the outlet of the heated medium of the first heat exchange section, and the outlet of the molten salt storage device is connected to the inlet of the heated medium of the second heat exchange section. It is configured to store the molten salt after absorbing heat from the boiler (1). A molten salt pumping device is disposed on the molten salt channel between the outlet of the molten salt storage device and the inlet of the heating medium of the second heat exchange unit, and is configured to pump the molten salt from the molten salt storage device to the second heat exchange unit.

3. The energy storage power generation system according to claim 2, characterized in that, The flow rate of the cold molten salt pumping device is adjustable; and / or The flow rate of the hot molten salt pumping device is adjustable; and / or Each of the molten salt circulation systems further includes a molten salt valve disposed between the outlet of the molten salt storage device and the inlet of the heated medium of the first heat exchange unit, the molten salt valve being configured to regulate the flow rate of the molten salt pumped from the molten salt storage device to the first heat exchange unit; and / or Each of the molten salt circulation systems further includes a molten salt valve disposed between the outlet of the molten salt storage device and the inlet of the heating medium of the second heat exchange unit, the molten salt valve being configured to regulate the flow rate of the molten salt pumped from the molten salt storage device to the second heat exchange unit.

4. The energy storage and power generation system according to claim 1, characterized in that, The first heat exchange device (3) further includes a tail flue heat exchange section disposed in the tail flue of the boiler (1), wherein the channel of the heated medium in the tail flue heat exchange section is connected in series with the channel of the heated medium in the radiant section heat exchange section and the channel of the heated medium in the convection section heat exchange section.

5. The energy storage and power generation system according to claim 1, characterized in that, The first working fluid heating device includes multiple liquid working fluid heaters arranged in series. The molten salt flows sequentially through the multiple liquid working fluid heaters to heat the liquid working fluid provided by the working fluid supply system. The liquid working fluid provided by the working fluid supply system flows sequentially through the multiple liquid working fluid heaters in order of increasing temperature of the molten salt.

6. The energy storage and power generation system according to claim 5, characterized in that, In the same second heat exchange section, the inlet of the heating medium of the second working fluid heating device and the inlet of the heating medium with the highest temperature among the plurality of liquid working fluid heaters are both connected to the hot molten salt channel, and the outlet of the heating medium of the second working fluid heating device is connected to the inlet of the heating medium with the closest temperature among the plurality of liquid working fluid heaters.

7. The energy storage power generation system according to any one of claims 1 to 6, characterized in that, The plurality of molten salt circulation systems include: The first molten salt circulation system uses the first molten salt as the heat exchange medium; and The second molten salt circulation system uses the second molten salt as the heat exchange medium. Wherein, the highest temperature of the first molten salt in the molten state is lower than the highest temperature of the second molten salt in the molten state.

8. The energy storage and power generation system according to claim 7, characterized in that, The first molten salt comprises 50% potassium nitrate and 50% sodium nitrate, by weight percentage; and / or The second molten salt comprises 21% sodium chloride, 31% barium chloride, and 48% calcium chloride, by weight percentage.

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