High-capacity calcium-based energy storage indirect steam generator

Abstract

The utility model relates to a large-capacity calcium-based energy storage indirect steam generator, which utilizes Ca (OH) 2-CaO chemical reaction circulation to realize energy storage and release circulation, energy is supplied in a low-pressure or medium-pressure steam form, and the large-capacity calcium-based energy storage indirect steam generator can also be suitable for alkaline earth metal hydroxide-oxide energy storage systems such as Mg (OH) 2 / MgO, Ba (OH) 2 / BaO and the like by adjusting system parameters. Electric energy generated by solar energy, wind energy, tidal energy and the like can be converted into heat energy, energy is stored in a chemical energy mode, and the effects of peak clipping and valley leveling are achieved; in some specific regions, unstable power supplies such as abandoned wind, abandoned light and abandoned water in some regions can be fully utilized; during energy storage, electric energy is consumed to heat and calcine metal hydroxide such as Ca (OH) 2, so that the metal hydroxide is converted into metal hydroxide such as CaO, and high-temperature steam is released at the same time; during energy release, CaO and H2O are subjected to a chemical reaction, and a large amount of heat is released to the outside in the form of medium-high temperature steam. The device has the characteristics of high energy storage density, low system self-energy consumption, large energy storage capacity, high steam quality, simple system, compact occupied area, high reliability, low investment, environment friendliness, wide adjustable range of output steam, low energy consumption cost, capability of realizing long-time and even cross-year energy storage and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of thermochemical energy storage, in particular to a large-capacity calcium-based energy storage indirect steam generator. Background Art

[0002] Since new energy power generation such as solar energy, wind energy, and tidal energy is intermittent and unstable, it is an unstable power source for the power grid in practical applications and requires other peak shaving units to be frequently adjusted to maintain the stability of the power grid.

[0003] If there is an energy storage method that can store a large amount of energy, be applied on a large scale, and have a low cost, which can store the electric energy generated by new energy such as solar energy, wind energy, and tidal energy to achieve peak shaving and valley filling, then the electricity generated by new energy will truly become a stable and reliable power source.

[0004] For users, the electricity price during peak hours of the power grid is also higher than that during valley hours. In order to reduce production / usage costs, there is actually a market demand for energy storage technology in many industrial and civil heating fields: storing energy during valley hours and using the stored heat during peak hours can relieve the power supply pressure of the power grid during peak hours and also reduce the electricity cost of users.

[0005] Current energy storage technologies have multiple technical routes. In the field of thermal energy storage, they can generally be divided into three main forms: sensible heat energy storage, latent heat energy storage, and thermochemical energy storage.

[0006] In the prior art, the sensible heat storage has a small heat storage density, serious heat loss during long-term storage, and a short heat storage cycle; the phase change heat storage with a higher energy storage density has problems such as two-phase separation, material leakage, and high-temperature corrosion.

[0007] Thermochemical energy storage has a high energy storage density, the reaction temperature can be selected high or low according to different energy storage substances, and it can be stored for a long time under almost lossless conditions. At present, the medium-temperature chemical energy storage systems of alkaline earth metal group metal oxides include: Ca(OH)2 / CaO system, Mg(OH)2 / MgO system, Ba(OH)2 / BaO system, etc. Among them, the Ca(OH)2 / CaO system energy storage material has a low price, and has the remarkable advantages of large energy storage density, non-toxic and non-corrosive in dry powder state, good safety, having achieved large-scale market supply, no side reactions, and a high reaction temperature (150°C - 430°C), and can well solve the energy storage applications of medium-temperature heat sources of various scales.

[0008] In the energy release stage, due to the low thermal conductivity of CaO solid particles and the large thermal resistance caused by the gas gaps between particles, the heat released by the synthesis reaction of CaO and H2O is difficult to be discharged, and some CaO cannot fully react, which limits the exothermic reaction and affects the energy release performance. If air or nitrogen and other gases are used as fluidizing media to make CaO solid particles react in a fluidized state, it will cause power loss of the fluidizing medium and exergy loss due to the addition of the fluidizing medium.

[0009] In the energy storage stage, the material particles are difficult to be heated evenly due to the low thermal conductivity of Ca(OH)2 solid particles and the large thermal resistance caused by the gas gaps between the particles, which makes the Ca(OH)2 reaction incomplete, and also affects the energy storage performance. If air or nitrogen and other gases are used as the fluidizing medium, it is also difficult to avoid the power loss of the fluidizing medium and the exergy loss caused by the addition of the fluidizing medium.

[0010] In the energy storage stage, Ca(OH)2 is heated to decompose into high-temperature CaO and water vapor. Due to the high temperature in the energy storage stage and the selection of reactor materials, it is almost impossible or extremely costly to obtain medium- and high-pressure steam. In the energy release stage (synthesis reaction of CaO and H2O), a large amount of heat is released. Under the premise of uniform mixing, most of the heat energy is released to convert water into steam, and a small part of the heat energy is absorbed by CaO and Ca(OH)2 (temperature increase). Therefore, medium- and high-temperature water vapor can be directly obtained in the energy storage and release stages. However, even with multi-stage filtration, this direct steam inevitably carries a certain amount of solid matter. In some occasions with high requirements for steam quality, this direct steam cannot be used.

[0011] In addition, since conventional calcium-based thermochemical energy storage and release systems are generally composed of Ca(OH)2 storage tanks, energy storage reactors, CaO storage tanks, transportation systems, fluidized air systems, dust removal systems, and multiple heat exchangers, they are bulky and complex, have high operating energy consumption, and high unit costs, making them basically impossible for households to use. Therefore, a thermochemical energy storage and release system with high design safety, compact structure, simple system, high efficiency and high reliability has become a technical problem that urgently needs to be solved.

[0012] The research on calcium-based thermochemical energy storage and release systems is still in its initial stage, and the country is only at the beginning stage of studying its basic performance. In order to make the thermochemical energy storage system more efficient and achieve a larger energy storage capacity, it is an important issue to be solved to design a large-capacity calcium-based energy storage indirect steam generator with high efficiency, large-capacity energy storage, high steam quality, low operating energy consumption, low cost, small footprint, safety and reliability, and suitable for large-scale promotion. Based on this, the utility model provides a large-capacity calcium-based energy storage indirect steam generator to solve the above problems. Utility Model Content

[0013] To solve the above technical problems, the purpose of the present utility model is to provide a large-capacity calcium-based energy storage indirect steam generator, which is an energy storage device with high energy storage efficiency, large energy storage capacity, low operating energy consumption, low unit initial investment, and land saving, realizing energy storage during part of the time and full-time energy supply, and effectively solving the problem of large-capacity energy storage in industry or civil use.

[0014] The present utility model provides a large-capacity calcium-based energy storage indirect steam generator. The calcium-based indirect steam generator is composed of a powder energy storage and release system, an atmospheric-pressure ash steam-water system, and a high-pressure steam-water system. The powder energy storage and release system is composed of a stirring reactor, a high-level storage bin, a feed pipe, a feeder, a filter, a front circulation air door, a circulation fan, a start-up circulation air duct, a rear circulation air door, a filter discharge valve, a filter discharge valve pipe, a discharge pipe, a first discharge valve, a high-temperature material steam superheater, a medium-temperature material evaporator, a low-temperature material water preheater, a second discharge valve, a low-level storage bin, a material elevator, a feeding valve, an electric heating controller, and an electric heating power supply cable; the electric heating device of the energy storage and release integrated reactor is connected to the power supply through the electric heating power supply cable and the electric heating controller; the atmospheric-pressure ash steam-water system is composed of a condenser inlet valve, an ejector, a condenser box, a condensation circulation fan, a condensation circulation regulating air door, a condensate pipe, a condensate collection tank, a spray pump, a spray water pipeline, and a spray water regulating valve according to the (ash-containing) atmospheric-pressure steam / water flow direction; the high-pressure steam-water system is composed of a feed pump, a feed water pipeline, a feed water stop valve, a feed water regulating valve, a primary feed water preheater, a primary feed water preheater outlet pipe, a low-temperature material water preheater, a water preheater outlet pipe, a steam-water separator, a circulation pump, a condensation evaporator inlet pipe, a condensation evaporator, a condensation evaporator outlet pipe, a medium-temperature material evaporator, an evaporator outlet pipe, an upper condensation superheater inlet steam pipe, a condensation superheater, a condensation superheater outlet steam pipe, a desuperheating water pipeline, a desuperheating water stop valve, a desuperheating water regulating valve, a spray desuperheater, a high-temperature material steam superheater, a main steam pipeline, and a main steam regulating valve according to the water / steam flow direction. Through the calcium-based indirect steam generator, the purpose of cyclic energy storage and utilization is realized.

[0015] Further explanation, the energy storage condition and the energy release condition share a powder energy storage and release system, so that the atmospheric-pressure ash steam-water system and the high-pressure steam-water system are also combined into one, achieving the purpose of maximizing the saving of the initial investment and land.

[0016] Further explanation, to prevent pulping or caking, the whole process of the material must be kept in a dry powder state. During the energy release stage, the amount of sprayed water is adjusted through the spray water regulating valve, and at the same time, the stirring claws in the stirring reactor uniformly stir the material, and the temperature of the material layer is always controlled to be 10°C to 60°C above the saturation temperature under the working pressure of the cylinder body.

[0017] Further explanation, in order to make the material react fully, the residence time of the material in the stirring reactor is adjustable, for example, it can be achieved by controlling the rotation speed and / or the forward and reverse rotation of the stirring claws.

[0018] It is further explained that during the energy storage period, the reaction temperature of the stirred reactor is maintained at 580°C~680°C under control, and the heating device of the stirred reactor can adopt a resistance heating method or an electromagnetic heating method.

[0019] Further explanation: In order to prevent the solid particles carried by the gas from adhering to and even clogging the filter due to the low pipe wall temperature during startup, the system is equipped with a startup circulation system, which consists of a front circulation damper, a circulation fan, a startup circulation air duct, a rear circulation damper, a stirring reactor and a filter to form a closed loop.

[0020] It is further explained that in order to ensure efficient heat exchange and condensation and maintain the slightly negative pressure working environment of the stirred reactor, a condensation circulation system is provided. According to the gas flow direction, the circulation is composed of an ejector, a condensation superheater, a condensation evaporator, a cold box, a condensation circulation fan and a condensation circulation regulating damper.

[0021] It is further explained that in order to improve the heat exchange efficiency, a first-stage feed water preheater is provided in the condensate collecting tank.

[0022] Further explanation: In order to further improve the condensation efficiency, a condensation water spray system can be added, which consists of a condensation water spray valve and a condensation water spray pipeline, and low-temperature water is directly sprayed into the internal space of the water-cooled box after the condensation evaporator.

[0023] Further explanation: according to needs, the superheated steam temperature can be set to 150~400℃, and the superheated steam pressure can be designed to be 0.5~5.3MPa.

[0024] It is further explained that the material temperature at the outlet of the low-temperature material water preheater can be cooled to 60~300℃ to meet the temperature requirements of the material conveying equipment.

[0025] It is further explained that by adding a bypass feeding pipe, a bypass feeding valve, a bypass unloading pipe, and a bypass unloading valve, and cooperating with tank truck transportation, emergency operating condition switching can be achieved, that is, switching from the energy storage condition to the energy release condition, or vice versa, switching from the energy release condition to the energy storage condition.

[0026] Further explanation: In order to ensure energy storage efficiency, all equipment, pipelines, valves, material conveying equipment, etc. need to be equipped with an external insulation layer, the thickness of which should ensure that the outer surface temperature is no more than 10℃~30℃ higher than the ambient temperature.

[0027] Further explanation: in order to reduce the dust content and reduce the adhesion of the heat exchange surface or pipes as much as possible, more stages of filters can be set as needed. In order to maintain continuous working capacity, the filters can be set to be replaceable online or a pneumatic back-blowing system can be added. Beneficial Effects

[0028] 1. The energy storage and release conditions of the utility model share a powder energy storage and release system, so that the atmospheric pressure ash steam-water system and the high-pressure steam-water system are also integrated into one, avoiding the need to set up a set of material storage and transportation, reactor and heat exchange system for Ca(OH)2 / CaO respectively, greatly simplifying the pipeline connection between subsystems, making the system unit investment and floor space much smaller than conventional calcium-based energy storage systems, and having great advantages in energy storage efficiency, economy and safety.

[0029] 2. Since steam is generated by interwall heat exchange, the limitations of the stirred reactor (1) (material selection and high temperature and high pressure sealing) are overcome, and high-quality high-pressure steam (which can meet the requirements of the steam turbine) can be obtained. The superheated steam temperature can be set to a range of 150~400℃, and the superheated steam pressure can be designed to be 0.5~5.3Mpa.

[0030] 3. Due to the use of a non-fluidized dry powder reaction process and the absence of any fluidizing medium, not only is the operating energy consumption ultra-low, but the system exergy efficiency is also much higher than that of conventional fluidized heat transfer methods.

[0031] 4. By using chemical energy storage, the physical sensible heat contained in high-temperature materials accounts for only a very small proportion. In addition, a high-performance insulation layer is laid, which can achieve higher energy storage efficiency and the system heat dissipation loss is less than 2%.

[0032] 5. The utility model can also produce a large amount of CaO by operating in a continuous energy storage state, and store it after cooling, thereby realizing long-term energy storage across years and locations.

[0033] 6. Due to the ultra-low operating energy consumption, after being equipped with a steam turbine generator, part of the high-temperature steam generated can be used for self-powered electricity generation, and the reserve CaO can be used to achieve long-term self-sustaining steam supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a general schematic diagram of the working process of the indirect steam generator of the utility model;

[0035] Figure 2 This is a general schematic diagram of the system workflow for adding water spray condensation to the utility model;

[0036] Figure 3 A schematic diagram of the overall working process of the system for adding a bypass to realize emergency switching of working conditions in the utility model;

[0037] The symbols in the accompanying drawings are:

[0038] 1. Stirring reactor; 2. High-level silo; 3. Feed pipe; 4. Feeder; 5. Filter; 6. Front circulation air damper; 7. Circulation fan; 8. Start-up circulation air duct; 9. Rear circulation air damper; 10. Filter discharge valve; 11. Filter discharge valve pipe; 12. Discharge pipe; 13. First discharge valve; 14. High-temperature material steam superheater; 15. Medium-temperature material evaporator; 16. Low-temperature material water preheater; 17. Second discharge valve; 18. Low-level silo; 19. Material elevator; 20. Loading valve; 21. Electric heating controller; 22. Electric heating power supply cable; 23. Condenser inlet valve; 24. Ejector; 25. Condensation circulation regulating air damper; 26. Condensation circulation fan; 27. Condenser box; 28. Condensate pipe; 29. Cold condensate box; 30. Spray water pump; 31. Spray water pipeline; 32. Spray water regulating valve; 33. Feed water pump; 34. Feed water pipeline; 35. Feed water stop valve; 36. Feed water regulating valve; 37. Primary feed water preheater; 38. Primary feed water preheater outlet pipe; 39. Water preheater outlet pipe; 40. Steam-water separator; 41. Circulation water pump; 42. Condensing evaporator inlet pipe; 43. Condensing evaporator; 44. Condensing evaporator outlet pipe; 45. Evaporator outlet pipe; 46. Condensing superheater inlet pipe; 47. Condensing superheater; 48. Condensing superheater outlet pipe; 49. Desuperheating water pipeline; 50. Desuperheating water stop valve; 51. Desuperheating water regulating valve; 52. Spray desuperheater; 53. Main steam pipeline; 54. Main steam regulating valve; 55. Condensing spray valve; 56. Condensing spray water pipeline; 57. Bypass feed pipe; 58. Bypass feed valve; 59. Bypass discharge pipe; 60. Bypass discharge valve. Detailed implementation mode

[0039] For the convenience of understanding the present utility model, the present utility model will be described more comprehensively below in conjunction with embodiments and drawings. The present utility model can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present utility model more thorough and comprehensive.

[0040] Embodiment 1: As Figure 1 shown, a large-capacity calcium-based energy storage indirect steam generator, the indirect steam generator is composed of a powder energy storage and release system, an atmospheric pressure ash steam-water system and a high-pressure steam-water system.

[0041] The described powder energy storage and release system consists of a stirring reactor (1), a high-level storage bin (2), a feed pipe (3), a feeder (4), a filter (5), a front circulation air damper (6), a circulation fan (7), a start-up circulation air duct (8), a rear circulation air damper (9), a filter discharge valve (10), a filter discharge valve pipe (11), a discharge pipe (12), a first discharge valve (13), a high-temperature material steam superheater (14), a medium-temperature material evaporator (15), a low-temperature material water preheater (16), a second discharge valve (17), a low-level storage bin (18), a material elevator (19), a loading valve (20), an electric heating controller (21), and an electric heating power supply cable (22). The electric heating device of the integrated energy storage and release reactor (1) is connected to the power supply through the electric heating power supply cable (22) and the electric heating controller (21).

[0042] The described atmospheric pressure ash steam-water system consists of a condenser inlet valve (23), an ejector (24), a condensate box (27), and a condensate circulation fan (26) according to the flow direction of the ash-containing atmospheric pressure steam water, and a condensate circulation regulating air damper (25), a condensate pipe (28), a condensate collection tank (29), a spray water pump (30), a spray water pipeline (31), and a spray water regulating valve (32).

[0043] The described high-pressure steam-water system consists of a feed water pump (33), a feed water pipeline (34), a feed water stop valve (35), a feed water regulating valve (36), a primary feed water preheater (37), a primary feed water preheater outlet pipe (38), a low-temperature material water preheater (16), a water preheater outlet pipe (39), a steam-water separator (40), a circulation water pump (41), a condensate evaporator inlet pipe (42), a condensate evaporator (43), a condensate evaporator outlet pipe (44), a medium-temperature material evaporator (15), an evaporator outlet pipe (45), an upper condensate superheater inlet steam pipe (46), a condensate superheater (47), a condensate superheater outlet pipe (48), a desuperheating water pipeline (49), a desuperheating water stop valve (50), a desuperheating water regulating valve (51), a spray desuperheater (52), a high-temperature material steam superheater (14), a main steam pipeline (53), and a main steam regulating valve (54) according to the water / steam flow direction. Through the calcium-based indirect steam generator, the purpose of cyclic energy storage and utilization is achieved.

[0044] Further explanation: A large-capacity calcium-based energy storage indirect steam generator uses a Ca(OH)₂-CaO thermochemical energy storage system. During the energy storage period (such as when powered by solar energy, wind energy, or valley electricity), the solid Ca(OH)₂ particles decompose under electrical heating to form CaO and high-temperature (580-680 °C) atmospheric or slightly negative-pressure steam. At the same time, most of the heat received is stored in the decomposition product CaO in the form of chemical energy, and the other part of the heat is carried by the physical sensible heat of the high-temperature steam and high-temperature CaO. After heat exchange, the physical sensible heat of the high-temperature steam and high-temperature CaO is exchanged with deaerated and desalted water to generate high-pressure steam. During the energy release period, under atmospheric or slightly negative-pressure conditions, CaO and H₂O undergo a reverse thermochemical reaction, releasing the chemical energy contained in CaO as heat. Under the condition of uniform stirring, all the heat at this time is converted into the physical sensible heat of high-temperature steam and high-temperature Ca(OH)₂. After heat exchange, this physical sensible heat is exchanged with deaerated and desalted water to generate high-pressure steam.

[0045] Further explanation: To prevent the solid particles carried by the gas from adhering to or even blocking the filter due to too low pipe wall temperature during startup, before the system is started cold, the system needs to be preheated first. The steps are as follows: Turn on the electric heating device of the stirring reactor (1), heat the internal gas temperature to 105-200 °C, then turn on the front circulation air damper (6) and the rear circulation air damper (9), and start the circulation fan (7). When the wall temperature of all startup circulation air pipes (8) exceeds 105-200 °C, turn off the circulation fan and the front and rear circulation air dampers. The system preheating is completed, and the stirring reactor (1) is allowed to feed.

[0046] Further explanation: During the energy storage period, the powdered Ca(OH)₂ material in the high-level storage bin (2) enters the stirring reactor (1) through the feed pipe (3) and the feeder (4) for metering. At this time, the system has completed preheating or is in a hot operation state. Turn on the electric heating device of the stirring reactor, and the electric heating controller (21) adjusts the heating power to keep the metal wall temperature at the bottom of the stirring reactor at 580-680 °C. At the same time, the residence time of the material is controlled by adjusting the rotation speed and / or the forward and reverse rotation of the stirring claws (such as rotating forward 3 circles and reversing 2 circles). When the material temperature exceeds 580 °C, the Ca(OH)₂ powder therein begins to decompose into CaO and steam. On the premise of sufficient stirring, the steam output depends on the input power of the electric heating device. When the electrolysis power is maintained unchanged and the stirring speed is continuously increased, when the wall temperature at the lower part of the stirring reactor rises rapidly and the internal pressure continues to drop, it means that the decomposition of Ca(OH)₂ is almost complete.

[0047] For further illustration, the working process of solid materials during the energy storage period is as follows: The high-temperature CaO generated by decomposition successively passes through the discharge pipe (12) and the first discharge valve (13) and enters the high-temperature material steam superheater (14) to exchange heat with high-pressure steam, passes through the medium-temperature material evaporator (15) to exchange heat with high-pressure water and evaporates it into saturated steam, and passes through the low-temperature material water preheater (16) to exchange heat with high-pressure low-temperature feed water. Then, the CaO powder material is cooled to 60 - 300 °C (usually set in the range of 100 - 150 °C for conventional applications). At this time, the temperature already meets the requirements of conventional material conveying equipment. The CaO powder material successively passes through the second discharge valve (17), the low-position storage bin (18), the material elevator (19), and the feeding valve (20) to the high-position storage bin (2), and the solid material completes the energy storage cycle process.

[0048] For further illustration, the working process of normal-pressure ash steam-water during the energy storage period is as follows: The high-temperature steam generated by decomposition, the solid particles separated by the filter (5) pass through the filter discharge valve (10) and enter the discharge pipe (12) after the first discharge valve (13) to converge with the material discharged from the stirring reactor and enter the high-temperature material steam superheater (14); the steam purified by the filter successively passes through the condenser inlet valve (23) and the ejector (24) and enters the condenser box (27). The steam is successively cooled by the condensation superheater (47) and the condensation evaporator (43) in the condenser box, and the temperature has been reduced to about 105 - 150 °C. Since the wall temperature of the condensation evaporator (43) is lower than the dew point temperature, a part of the steam is condensed into liquid and collected in the condenser box and flows along the condensate pipe (28) into the lower-position condensate collection tank (29); to ensure efficient heat exchange and condensation, it is necessary to ensure a sufficiently high gas flow scouring speed outside the tube bundles of the condensation superheater and the condensation evaporator. Adjust the rotation speed of the condensation circulation fan (26) so that the gas successively passes through the condenser box (27), the condensation circulation regulating air damper (25), and the ejector (24) and then returns to the condenser box to form a gas cycle. The heat transfer and condensation are enhanced by adjusting the gas circulation ratio to adjust the gas flow scouring speed; under the dual negative pressure effects of steam condensation and the ejector, it can be ensured that the stirring reactor (1) always operates in a slightly negative pressure working environment to prevent steam or material leakage; the condensate water in the condensate collection tank (29) is cooled to low-temperature condensate water by the primary feed water preheater (37), then pressurized by the spray water pump (30), and successively passes through the spray water pipeline (31) and the spray water regulating valve (32) and is sprayed into the stirring reactor (1), and the normal-pressure ash steam-water completes the energy storage process.

[0049] For further illustration, see Attachment Figure 2 , to further improve the condensation efficiency, a condensation water spraying system can be added, which consists of a condensation water spraying valve (55) and a condensation water spraying pipeline (56), and low-temperature water is atomized and sprayed into the internal space of the water condenser box (27) after the condensation evaporator (43).

[0050] For further illustration, the high-pressure steam-water working process during the energy storage period is as follows: The water coming out of the feed water pump (33) is divided into two paths, namely feed water and desuperheating spray water. The feed water enters the primary feed water preheater (37) successively through the feed water pipeline (34), the feed water stop valve (35), and the feed water regulating valve (36). The heated feed water enters the low-temperature material water preheater (16) through the outlet pipe (16) of the primary feed water preheater, is heated again by the material, and then enters the steam-water separator (40) through the outlet pipe (39) of the water preheater; the water temperature in the steam-water separator is subcooled water, which is pressurized by the circulating water pump (41) and flows through the inlet pipe (42) of the condensation evaporator, the condensation evaporator (43), the outlet pipe (44) of the condensation evaporator, the medium-temperature material evaporator (15), and the outlet pipe (45) of the evaporator in sequence. The saturated steam-water mixture returns to the steam-water separator for steam-water separation, forming a forced circulation loop. After two-stage heat exchange in the condensation evaporator and the medium-temperature material evaporator, a large amount of water is heated to the saturation temperature to form saturated steam, which accumulates in the upper part of the steam-water separator; the saturated steam in the steam-water separator passes through the inlet pipe (46) of the condensation superheater, the condensation superheater (47), and the outlet pipe (48) of the condensation superheater to reach the spray desuperheater (52) in sequence; the desuperheating spray water coming out of the feed water pump (33) is atomized and sprayed into the spray desuperheater (52) through the desuperheating water pipeline (49), the desuperheating water stop valve (50), and the desuperheating water regulating valve (51) to converge with the main steam from the condensation superheater and reduce the temperature. The desuperheated main steam enters the high-temperature material steam superheater (14) and is heated again to avoid steam carrying water, and then is supplied through the main steam pipeline (53) and the main steam regulating valve (54).

[0051] For further illustration, during the energy release stage, the working process of the solid material is exactly the same as that during the energy storage period, except that the reactants, products, and corresponding working conditions in the stirring reactor (1) are different; the rotation speed of the stirring claws in the stirring reactor is adjusted to ensure sufficient residence time of the material in the reactor and keep it fully stirred evenly. The amount of water sprayed into the reactor is adjusted by controlling the spray water regulating valve (32). When liquid water comes into contact with CaO, a reaction occurs rapidly to generate Ca(OH)2 and release a large amount of heat, causing the material layer to heat up rapidly. Part of the liquid water absorbs heat and vaporizes into high-temperature steam. According to needs, the high-temperature steam in the upper gas space of the reactor can be maintained at a certain temperature (adjustable within the range of 150 - 450 °C), and the reactor is maintained at normal pressure or slightly negative pressure by adjusting the condensation circulation regulating air damper (25); when the spray water volume remains unchanged and the stirring speed of the reduction motor (2) is continuously increased, when the temperature of the material at the lower part of the cylinder still drops continuously, it means that the CaO is almost consumed.

[0052] Further explanation: The energy release cycle process of solid materials is exactly the same as the energy storage cycle process, except for the materials. In the energy release cycle process, the inlet of the reactor is CaO and the outlet is Ca(OH)2. On the contrary, in the energy storage cycle process, the inlet of the reactor is Ca(OH)2 and the outlet is CaO.

[0053] Further explanation: During the energy release period, the working processes of atmospheric pressure ash steam water and high-pressure steam water are exactly the same as those during the energy storage period.

[0054] Further explanation: The energy storage material adopted by the present utility model is the Ca(OH)2 - CaO system. Through the adjustment of system parameters, it can also be applicable to energy storage systems of alkaline earth metal hydroxides - oxides such as Mg(OH)2 / MgO and Ba(OH)2 / BaO.

[0055] Further explanation: The powder energy storage and release system and the core equipment are the stirring reactor (1). This reactor can complete the energy storage reaction and the energy release reaction. It is a horizontally arranged cylindrical barrel. The barrel is filled with materials. One end of its central axis is provided with a reduction motor. Along the central axis inside the barrel, there is a stirring shaft, and a plurality of stirring claws are connected thereto. In order to ensure the uniformity of the energy release reaction, the water spraying of the stirring reactor should be arranged at multiple points to ensure uniformity. At the top of one end of the reactor barrel, there is a feed inlet. At the top of the other end of the barrel, there is a primary filter, and at the bottom, there is a discharge outlet. Since the temperature of the energy storage and release reactions needs to be considered, the barrel material can be made of steels such as 1Cr13 and SUS 304. In order to reduce heat dissipation loss, the entire reactor is covered with a heat insulation layer (required to be heat-resistant above 800°C). In order to ensure higher heat exchange efficiency, the preferred particle size range of the CaO particle material is 100 - 500 μm. The electric heating device of the stirring reactor (1) is laid in the area of the bottom of the barrel where there is material, and the resistance heating or electromagnetic heating method can be selected. If the electromagnetic heating method is adopted, the barrel material should be correspondingly selected as the steel that matches the electromagnetic heating performance.

[0056] Further explanation: The working temperature of the filter (5) of the powder energy storage and release system can reach up to 680°C at most. Therefore, a high-temperature resistant ceramic filter element with a filter aperture of 10 - 50 μm is preferably selected.

[0057] Further explanation: The circulating fan (7) of the powder energy storage and release system should be selected as a medium-temperature fan with a temperature resistance of 250°C, and its head and flow rate are selected according to the diameter of the stirring reactor (1).

[0058] Further explanation: The working temperatures of the first discharge valve (13) and the filter blanking valve (10) of the powder energy storage and release system are as high as 680°C. In order to resist thermal deformation and solid material wear, rare earth heat-resistant cast steel is preferably selected as the main material of the valve body.

[0059] Further explanation: The highest working temperature of the discharge pipe (12) of the powder energy storage and release system is up to 680 °C. It is preferred to use a high-temperature falling material pipe with a heat insulation structure that is thin in heat insulation thickness and light in weight. The second choice is a conventional heavy-duty high-temperature falling material pipe with a wear-resistant, (adiabatic,) heat-insulating material laid inside the carbon steel outer wall.

[0060] Further explanation: The high-temperature material steam superheater (14), medium-temperature material evaporator (15), and low-temperature material water preheater (16) of the powder energy storage and release system are powder-fluid heat exchangers. It is preferred to use an immersion heat exchanger with a membrane wall structure for the shell, and the second choice is a vibrating heat exchanger.

[0061] Further explanation: The working process of a large-capacity calcium-based energy storage indirect steam generator is as follows:

[0062] During the energy storage period, the powdered Ca(OH)2 material in the high-level storage bin (2) enters the stirring reactor (1). Start the electric heating device of the stirring reactor to keep the metal wall temperature at the bottom of the stirring reactor at 580 - 680 °C. By controlling the residence time of the material through the rotation speed of the stirring claws and / or the ratio of forward and reverse rotation time, the generated high-temperature CaO is cooled to 60 - 300 °C (usually set in the range of 100 - 150 °C in conventional applications) successively through the high-temperature material steam superheater (14), medium-temperature material evaporator (15), and low-temperature material water preheater (16). Then the material successively passes through the second discharge valve (17), low-level storage bin (18), material elevator (19), and feeding valve (20) and returns to the high-level storage bin (2), and the solid material completes the energy storage cycle process.

[0063] Further explanation: The working process of the solid material during the energy storage period: The generated high-temperature CaO successively passes through the discharge pipe (12) and the first discharge valve (13) and enters the high-temperature material steam superheater (14) to exchange heat with high-pressure steam, passes through the medium-temperature material evaporator (15) to exchange heat with high-pressure water and evaporates it into saturated steam, and passes through the low-temperature material water preheater (16) to exchange heat with high-pressure low-temperature feed water. After that, the CaO powder is cooled to 60 - 300 °C (usually set in the range of 100 - 150 °C in conventional applications). At this time, the temperature already meets the requirements of conventional material conveying equipment. The CaO material successively passes through the second discharge valve (17), low-level storage bin (18), material elevator (19), and feeding valve (20) to the high-level storage bin (2), and the solid material completes the energy storage cycle process.

[0064] For further illustration, the working process of normal-pressure ash steam-water during the energy storage period is as follows: The solid particles separated by the filter (5) enter the discharge pipe (12) through the filter discharge valve (10) after the first discharge valve (13) and converge with the materials discharged from the stirring reactor to enter the high-temperature material steam superheater (14); The purified steam sequentially passes through the condenser inlet valve (23) and the ejector (24) and enters the condenser box (27). The steam is cooled sequentially by the condensation superheater (47) and the condensation evaporator (43) in the condenser box, and the temperature has been reduced to about 105-150 °C. The condensed water is collected and enters the condensate collection tank (29) along the condensate pipe (28). The rotation speed of the condensation circulation fan (26) is adjusted to adjust the gas circulation ratio to achieve enhanced heat transfer and condensation. The condensed water in the condensate collection tank (29) is cooled by the primary feed water preheater (37) and then pressurized by the spray water pump (30). It is sprayed into the stirring reactor (1) after passing through the spray water pipeline (31) and the spray water regulating valve (32) in sequence, and the normal-pressure ash steam-water completes the energy storage process.

[0065] For further illustration, the working process of high-pressure steam-water during the energy storage period is as follows: The water coming out of the feed water pump (33) is divided into two paths: feed water and desuperheating spray water. The feed water is preheated along the feed water pipeline (34) through the primary feed water preheater (37) and the low-temperature material water preheater (16) in sequence and then enters the steam-water separator (40); The undersaturated water in the steam-water separator is pressurized by the circulating water pump (41) and flows through the condensation evaporator (43) and the medium-temperature material evaporator (15) in sequence to form a saturated steam-water mixture and return to the steam-water separator for steam-water separation, forming a forced circulation loop; The saturated steam in the steam-water separator passes through the condensation superheater (47), the spray desuperheater (52) and the high-temperature material steam superheater (14) in sequence and is reheated to avoid steam carrying water, and then is supplied through the main steam regulating valve (54).

[0066] For further illustration, during the energy release period, the working process of the solid material is the same, except that the inlet material of the stirring reactor (1) is CaO powder and the outlet material is Ca(OH)2 powder. The working processes of the normal-pressure ash steam-water and the high-pressure steam-water are also exactly the same as those during the energy storage period.

[0067] For further illustration, as Figure 3 shown, by adding a bypass feed pipe (57), a bypass feed valve (58), a bypass discharge pipe (59), and a bypass discharge valve (60), and cooperating with tanker transportation, the emergency condition switching can be realized, and the condition switching form is switched from the energy storage condition to the energy release condition or vice versa from the energy release condition to the energy storage condition.

[0068] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A large-capacity calcium-based energy storage indirect steam generator, characterized in that: The calcium-based indirect steam generator is composed of a powder energy storage and release system, a normal pressure ash-steam-water system and a high pressure steam-water system. The powder energy storage and release system is composed of a stirring reactor (1), a high-level silo (2), a feeding pipe (3), a feeder (4), a filter (5), a front circulation damper (6), a circulation fan (7), a start-up circulation air duct (8), a rear circulation damper (9), a filter blanking valve (10), a filter blanking valve pipe (11), a discharge pipe (12), a first discharge valve (13), a high-temperature material steam superheater (14), a medium-temperature material evaporator (15), and a low-temperature material The material water preheater (16), the second discharge valve (17), the low-level material bin (18), the material elevator (19), the loading valve (20), the electric heating controller (21) and the electric heating power supply cable (22); the electric heating device of the energy storage and release integrated reactor (1) is connected to the power supply through the electric heating power supply cable (22) and the electric heating controller (21); the atmospheric pressure ash steam and water system is composed of a condenser inlet valve (23), an ejector (24), a condenser box (27), a condensation circulation fan (26), a condensation circulation regulating damper (25) according to the direction of the atmospheric pressure steam / water containing ash. ), condensate pipe (28), condensate collecting tank (29), water spray pump (30), water spray pipeline (31) and water spray regulating valve (32); the high-pressure steam-water system is composed of a feed water pump (33), a feed water pipeline (34), a feed water stop valve (35), a feed water regulating valve (36), a first-stage feed water preheater (37), a first-stage feed water preheater outlet pipe (38), a low-temperature material water preheater (16), a water preheater outlet pipe (39), a steam-water separator (40), a circulating water pump (41), a condenser evaporator inlet pipe (42), a condenser The invention is composed of an evaporator (43), a condenser evaporator outlet pipe (44), a medium-temperature material evaporator (15), an evaporator outlet pipe (45), an upper condenser superheater steam inlet pipe (46), a condenser superheater (47), a condenser superheater outlet pipe (48), a cooling water pipeline (49), a cooling water stop valve (50), a cooling water regulating valve (51), a water spray desuperheater (52), a high-temperature material steam superheater (14), a main steam pipeline (53) and a main steam regulating valve (54), and realizes the purpose of cyclic energy storage and utilization through a calcium-based indirect steam generator.

2. According to claim 1, a large-capacity calcium-based energy storage indirect steam generator is characterized in that: The energy storage condition and the energy release condition share a powder energy storage and release system, so that the normal pressure ash steam-water system and the high pressure steam-water system are also integrated into one, achieving the purpose of saving investment and land.

3. According to claim 1, a large-capacity calcium-based energy storage indirect steam generator is characterized in that: In order to prevent slurry agglomeration, the material must be kept in a dry powder state throughout the process. In the energy release stage, the water spraying amount is adjusted by the water spraying regulating valve (32), and at the same time, the stirring claws in the stirring reactor (1) are used to stir the material evenly, so that the temperature of the material layer is always controlled to be 10°C to 60°C higher than the saturation temperature under the working pressure of the cylinder.

4. According to claim 1, a large-capacity calcium-based energy storage indirect steam generator is characterized in that: During the energy storage period, the reaction temperature of the stirred reactor (1) is controlled and maintained at 580° C. to 680° C., and the heating device of the stirred reactor may adopt a resistance heating method.

5. According to claim 1, a large-capacity calcium-based energy storage indirect steam generator is characterized in that: In order to prevent the solid particles carried by the gas from adhering to or even clogging the filter due to the excessively low pipe wall temperature during startup, the system is provided with a startup circulation system, which is composed of a front circulation damper (6), a circulation fan (7), a startup circulation air duct (8), a rear circulation damper (9), a stirring reactor (1) and a filter (5) to form a closed loop.

6. A large-capacity calcium-based energy storage indirect steam generator according to claim 1, characterized in that: In order to ensure efficient heat exchange and condensation and maintain the slightly negative pressure working environment of the stirred reactor (1), a condensation circulation system is provided. According to the gas flow direction, a circulation is formed by an ejector (24), a condensation superheater (47), a condensation evaporator (43), a cold box (27), a condensation circulation fan (26) and a condensation circulation regulating damper (25). In order to improve the heat exchange efficiency, a first-stage feed water preheater (37) is provided in the condensation water collecting tank (29).

7. A large-capacity calcium-based energy storage indirect steam generator according to claim 1, characterized in that: In order to further improve the condensation efficiency, a condensation water spray system can be added, which is composed of a condensation water spray valve (55) and a condensation water spray pipeline (56), and low-temperature water is directly sprayed into the internal space of the water-cooled box (27) after the condensation evaporator (43).

8. A large-capacity calcium-based energy storage indirect steam generator according to claim 1, characterized in that: According to needs, the superheated steam temperature can be set to 150~400℃, and the superheated steam pressure can be designed to be 0.5~5.3MPa.

9. A large-capacity calcium-based energy storage indirect steam generator according to claim 1, characterized in that: The material temperature at the outlet of the low-temperature material water preheater (16) can be cooled to 60-300°C to meet the temperature requirement of the material conveying equipment.

10. A large-capacity calcium-based energy storage indirect steam generator according to claim 1, characterized in that: By adding a bypass feeding pipe (57), a bypass feeding valve (58), a bypass unloading pipe (59), and a bypass unloading valve (60), and in conjunction with tank truck transportation, emergency operating condition switching can be achieved, and the operating condition switching form is switched from the energy storage operating condition to the energy release operating condition or vice versa, from the energy release operating condition to the energy storage operating condition.

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