Sludge drying energy storage system, control method thereof and power generation system assembly

Abstract

The invention relates to a sludge drying energy storage system and a control method thereof and a power generation system assembly.The sludge drying energy storage system comprises an electric heat storage unit and a sludge drying unit, the electric heat storage unit comprises a motor, a compressor, a heat storage device and an expansion machine, the motor is connected to the compressor, the compressor is connected to the expansion machine, and the heat storage device is connected to the expansion machine; an inlet of the heat storage device is connected to the compressor, an outlet of the heat storage device is connected to the expansion machine and the sludge drying unit, an outlet of the expansion machine is connected to the sludge drying unit, and the sludge drying system can dry sludge under the condition of not depending on fossil fuel so as to improve the adjusting flexibility of a coal power unit.

Description

Technical Field

[0001] This disclosure relates to the field of thermal energy storage technology, specifically to a sludge drying energy storage system, its control method, and a power generation system assembly. Background Technology

[0002] In related technologies, coal-fired power units typically use fossil fuel-dependent methods such as coal co-firing to dry sludge. However, sludge drying requires a lot of energy, resulting in a large overall workload for coal-fired power units, which can easily lead to a decrease in the regulating performance of coal-fired power units. Therefore, how to achieve sludge drying without using fossil fuels such as coal while improving the regulating flexibility of coal-fired power units is an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this disclosure is to provide a sludge drying energy storage system, its control method, and a power generation system assembly, which can dry sludge without relying on fossil fuels, thereby improving the flexibility of coal-fired power unit regulation and at least partially solving the aforementioned technical problems.

[0004] To achieve the above objectives, a first aspect of this disclosure provides a sludge drying and energy storage system, comprising an electric thermal storage unit and a sludge drying unit, wherein the electric thermal storage unit includes an electric motor, a compressor, a thermal storage device, and an expander, the electric motor is connected to the compressor, the compressor is connected to the expander, the inlet of the thermal storage device is connected to the compressor, the outlet of the thermal storage device is connected to the expander and the sludge drying unit respectively, and the outlet of the expander is connected to the sludge drying unit.

[0005] Optionally, the heat storage device includes a plurality of heat storage tanks connected in sequence, and the outlet of at least one of the heat storage tanks is connected to the expander and the sludge drying unit.

[0006] Optionally, the sludge drying unit includes: a drying device connected to the outlet of the heat storage device and the outlet of the expander; a storage device connected to the outlet of the drying device; and a grinding device connected to the outlet of the storage device.

[0007] Optionally, the sludge drying unit further includes a filter device that is circulated and connected to the drying device, and the outlet of the filter device is also connected to the inlet of the compressor.

[0008] Optionally, the sludge drying energy storage system further includes a low-temperature heat exchanger located between the filtration device and the compressor.

[0009] A second aspect of this disclosure provides a control method for a sludge drying energy storage system. The method is applied to any of the optional embodiments described above. The method includes a heat storage process and a heat release process. The heat storage process includes: an electric motor driving a compressor, the compressor compressing high-temperature gas to heat a heat storage device, and the heat storage device discharging the high-temperature gas to a sludge drying unit. The heat release process includes: the heat storage device discharging the high-temperature gas to an expander, the expander expanding the high-temperature gas and discharging it to the sludge drying unit.

[0010] A third aspect of this disclosure provides a power generation system assembly, including a power generation device and a sludge drying and energy storage system as described in any of the above alternatives, wherein the outlet of the sludge drying unit of the sludge drying and energy storage system is connected to the power generation device.

[0011] Optionally, the power generation device includes: a heat exchange boiler, the inlet of which is connected to the outlet of the sludge drying unit, and the outlet of which is connected to the compressor; a steam turbine, the inlet of which is connected to the heat exchange boiler; a condenser, the inlet of which is connected to the outlet of the steam turbine, and the outlet of which is connected to the heat exchange boiler; and a generator connected to the steam turbine.

[0012] Optionally, the power generation unit further includes an exhaust cooler located between the outlet of the condenser and the heat exchange boiler.

[0013] Optionally, the power generation device further includes a feedwater pump connected to the exhaust cooler and the heat exchange boiler.

[0014] Through the above-mentioned technical solution, namely the sludge drying and energy storage system provided in this disclosure, when sludge is dried through the sludge drying and energy storage system, the heat storage device can be used for heat storage. That is, the compressor is driven by an electric motor, and the high-temperature gas discharged from the compressor outlet can heat the heat storage body in the heat storage device. The hot air discharged after the heat storage body is heated will enter the sludge drying system to dry the sludge for the first time. When the heat storage device releases heat, the hot air discharged from the heat storage body in the heat storage device can enter the expander turbine to do work and then be fed into the sludge drying unit, thereby drying the sludge for the second time. Through the above-mentioned sludge drying operation, the sludge can be dried entirely by electric drive without relying on fossil fuels. Furthermore, the heat storage method can be used for sludge drying when the coal-fired power unit load is low, and the heat release method can be used for secondary drying of sludge when the coal-fired power unit load is high, thereby improving the flexibility of coal-fired power unit regulation.

[0015] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the power generation system assembly provided in an exemplary embodiment of this disclosure; Figure 2 This is a schematic diagram of the heat storage process of the sludge drying and energy storage system provided in an exemplary embodiment of this disclosure; Figure 3 This is a schematic diagram of the heat release process of the sludge drying and energy storage system provided in an exemplary embodiment of this disclosure.

[0017] Explanation of reference numerals in the attached figures 1-Electric thermal storage unit; 110-Electric motor; 120-Compressor; 130-Thermal storage device; 131-Thermal storage tank; 140-Expander; 2-Sludge drying unit; 210-Drying device; 220-Storage device; 230-Grinding device; 240-Filtering device; 3-Low-temperature heat exchanger; 4-Power generation unit; 410-Heat exchange boiler; 420-Steam turbine; 430-Condenser; 440-Generator; 450-Exhaust gas cooler; 460-Feed water pump. Detailed Implementation

[0018] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0019] In this disclosure, unless otherwise stated, directional terms such as "inner" and "outer" refer to the inner and outer contours of the structure or component itself; terms such as "first" and "second" are used to distinguish one element from another and do not have sequentiality or importance; in addition, the same reference numerals in different reference drawings indicate the same element, and the same reference numerals in the same drawing also indicate the same element.

[0020] A first aspect of this disclosure provides a sludge drying and energy storage system, with reference to... Figures 1 to 3 As shown, the sludge drying and energy storage system includes an electric thermal storage unit 1 and a sludge drying unit 2. The electric thermal storage unit 1 includes an electric motor 110, a compressor 120, a thermal storage device 130, and an expander 140. The electric motor 110 is connected to the compressor 120, the compressor 120 is connected to the expander 140, the inlet of the thermal storage device 130 is connected to the compressor 120, the outlet of the thermal storage device 130 is connected to the expander 140 and the sludge drying unit 2, and the outlet of the expander 140 is connected to the sludge drying unit 2.

[0021] Through the above-described scheme, namely the sludge drying energy storage system provided in this disclosure, when sludge is dried using this sludge drying energy storage system, heat storage device 130 can be used for heat storage. Specifically, the compressor 120 is driven by the motor 110, and the high-temperature gas discharged from the outlet of the compressor 120 can heat the heat storage body inside the heat storage device 130. After the heat storage body is heated, the discharged hot air will enter the sludge drying unit 2 to perform a primary drying of the sludge. When the heat storage device 130 releases heat, the heat storage device 130... The hot air discharged from the heat storage body can enter the expander 140 to expand the turbine and then be fed into the sludge drying unit 2, thereby allowing for secondary drying of the sludge. Through the above-mentioned sludge drying operation, the sludge can be dried entirely by electric drive without relying on fossil fuels. Furthermore, when the coal-fired power unit load is low, the heat storage method can be used for sludge drying, while when the coal-fired power unit load is high, the heat release method can be used for secondary drying of the sludge, thereby improving the flexibility of coal-fired power unit regulation.

[0022] In some implementations, reference Figures 1 to 3 As shown, the heat storage device 130 includes multiple heat storage tanks 131 connected in sequence, with the outlet of at least one heat storage tank 131 connected to the expander 140 and the sludge drying unit 2. In this way, when the high-temperature gas discharged from the compressor 120 enters the heat storage device 130, it sequentially fills the multiple heat storage tanks 131 for storage, allowing more heat to be stored within the heat storage tanks 131. When the sludge drying system needs to release heat to perform work, more heat can be released for the sludge drying unit 2 to perform sludge drying operations. For example, refer to... Figure 1 As shown, in Figure 1 In the illustrated embodiment, there may be two heat storage tanks 131. One of the two heat storage tanks 131 is connected to the expander 140 and the sludge drying unit 2, and this heat storage tank 131 is also connected to the compressor 120. That is, it can be understood that during the operation of the sludge drying system in the heat storage process, part of the heat from the high-temperature gas discharged by the compressor 120 can be stored in multiple heat storage tanks 131. When the heat in multiple heat storage tanks 131 is stored to the maximum extent, the remaining heat from the high-temperature gas discharged by the compressor 120 will directly pass through multiple heat storage tanks 131 and enter the sludge drying unit 2, so as to dry the sludge for the first time using the heat from this part of the high-temperature gas. During the operation of the sludge drying system in the heat release process, the heat stored in multiple heat storage tanks 131 will be released into the expander 140. After the expander 140 expands and the turbine does work, more heat is supplied to the sludge drying unit 2, and then the sludge can be dried for the second time using the released more heat.

[0023] Furthermore, the two thermal storage tanks 131 mentioned in the above embodiments are merely exemplary. In embodiments not shown in the accompanying drawings, the number of thermal storage tanks 131 may also be three, four, or more. This disclosure does not specifically limit this. Moreover, the thermal storage material used in the thermal storage tank 131 may also be a material that is widely available in the prior art. For example, the thermal storage material may be a molten salt or a carbon-based graphite thermal storage material. In order to avoid deviating from the technical solution of this disclosure, no further details will be provided here.

[0024] It should be further explained that the electric-driven sludge drying method mentioned in the above embodiments is not only to improve the flexibility of coal-fired power unit regulation, but also to reduce the environmental pollution caused by fossil fuel combustion by drying sludge without relying on fossil fuels, thus achieving the effect of green and environmentally friendly sludge drying.

[0025] In some implementations, reference Figures 1 to 3 As shown, the sludge drying unit 2 includes a drying device 210, a storage device 220, and a grinding device 230. The drying device 210 is connected to the outlet of the heat storage device 130 and the outlet of the expander 140; the storage device 220 is connected to the outlet of the drying device 210; and the grinding device is connected to the outlet of the storage device 220. With this arrangement, the drying device 210 can be supplied with hot air discharged from the compressor 120 via the heat storage device 130 or hot air that has passed through the expansion turbine of the expander 140, to dry the sludge with high moisture content that is temporarily stored in the drying device 210. After drying the sludge with high moisture content, the volume of the sludge can be further reduced and discharged into the storage device 220. The storage device 220 can be a storage bin for storing sludge. The dried sludge can be stored in the storage device 220. When it is necessary to co-fire the stored sludge, the sludge stored in the storage device 220 can be ground in the grinding device 230. The grinding device 230 can be a grinder capable of grinding sludge. After the sludge is ground into fine particles, it can be transported to the co-firing equipment (such as a boiler) for co-firing. The heat generated by co-firing can also be used for thermal power generation, thereby improving the energy utilization rate after sludge co-firing and avoiding waste.

[0026] In some implementations, reference Figures 1 to 3As shown, the sludge drying unit 2 also includes a filter device 240 that is circulated and connected to the drying device 210. The outlet of the filter device 240 is also connected to the inlet of the compressor 120. In this way, after the sludge with high moisture content has been dried by hot air, the filter device 240 filters the remaining air, thereby reducing dust or impurities in the air. This filtered air can then be returned to the compressor 120 for heating, thereby improving the utilization rate of air circulation in the sludge drying system.

[0027] In some implementations, reference Figures 1 to 3 As shown, the sludge drying and energy storage system also includes a low-temperature heat exchanger 3 located between the filter device 240 and the compressor 120. In this way, the low-temperature heat exchanger 3 can cool and depressurize the air discharged from the filter device 240 and returned to the compressor 120, thereby making the temperature and pressure of the air returning from the filter device 240 to the compressor 120 more consistent with the air drawn into the compressor 120 from the external environment, reducing the temperature and pressure difference, and thus allowing the compressor 120 to compress air more stably.

[0028] A second aspect of this disclosure provides a control method for a sludge drying energy storage system. The method includes a heat storage process and a heat release process. The heat storage process includes: an electric motor 110 drives a compressor 120, the compressor 120 compresses high-temperature gas to heat a heat storage device 130, and the heat storage device 130 discharges the high-temperature gas to a sludge drying unit 2. The heat release process includes: the heat storage device 130 discharges the high-temperature gas to an expander 140, and the expander 140 expands the high-temperature gas and discharges it to the sludge drying unit 2. Under this operating mode, the sludge drying energy storage unit can achieve two working modes: heat storage and heat release. Specifically, during heat storage, the high-temperature gas compressed by the compressor 120 enters the heat storage device 130 and is stored by the heat storage medium within the device. When the heat storage device 130 is full of high-temperature air, the high-temperature gas compressed by the compressor 120 can be directly discharged through the heat storage device 130 to the sludge drying unit 2 for primary sludge drying. When the sludge drying requirement is high, heat release can be used. The high-temperature gas is discharged through the heat storage medium in the heat storage device 130 to the expander 140 for expansion. The expanded high-temperature gas then enters the sludge drying unit 2 for secondary sludge drying, thereby improving the sludge drying effect. This avoids using fossil fuels for sludge drying while also meeting the flexibility of unit adjustment when the coal-fired unit has a high load (such as the aforementioned situation with a high sludge drying requirement).

[0029] It should be noted that the temperature of the high-temperature gas mentioned in the above embodiments can be in the range of 400±10℃, and the gas at this temperature can dry the sludge.

[0030] A third aspect of this disclosure provides a power generation system assembly, with reference to Figures 1 to 3 As shown, the power generation system assembly includes a power generation unit 4 and the sludge drying and energy storage system mentioned in the above specific embodiment. The outlet of the sludge drying unit 2 of the sludge drying and energy storage system is connected to the power generation unit 4. In this way, after the sludge is dried by the sludge drying and energy storage system, the dried sludge can be discharged into the power generation unit 4 for thermal power generation. The power generation unit 4 can be a thermal power generation device, a steam turbine generator set, etc. Through the combined power generation of the sludge drying and energy storage system and the power generation unit 4, efficient thermal-electric conversion can be achieved.

[0031] In some implementations, reference Figures 1 to 3 As shown, the power generation unit 4 includes a heat exchange boiler 410, a steam turbine 420, a condenser 430, and a generator 440. The inlet of the heat exchange boiler 410 is connected to the outlet of the sludge drying unit 2, and the outlet of the heat exchange boiler 410 is connected to the compressor 120. The air inlet of the steam turbine 420 is connected to the heat exchange boiler 410. The air inlet of the condenser 430 is connected to the air outlet of the steam turbine 420, and the air outlet of the condenser 430 is connected to the heat exchange boiler 410. The generator 440 is connected to the steam turbine 420. In this way, the sludge dried in the sludge drying unit 2 can be used for thermal power generation in the heat exchange boiler 410, which can be referenced... Figure 1 As shown, the sludge discharged from the grinding device 230 can be co-fired in the heat exchange boiler 410. The heat generated by co-firing can be used to exchange heat with the gas discharged from the condenser 430 into the heat exchange boiler 410. After the gas is heated by heat exchange, it can be discharged into the steam turbine 420 to generate electricity. The electrical energy can be supplied to the generator 440 for use. Through the above method, efficient thermoelectric conversion can be achieved, that is, the heat generated by sludge co-firing can be used to generate electricity in the power generation device 4, which can reduce the waste of heat released by sludge co-firing.

[0032] It should be noted that the electric motor 110, compressor 120, expander 140 and heat exchange boiler 410 mentioned in the above embodiments can jointly form a set of high-efficiency Carnot batteries. The heat storage process, heat release process and sludge co-firing for thermal power generation mentioned in the above embodiments can be used in conjunction with the peak and valley periods of the power grid where the power generation system is located. That is to say, during the peak period of the power grid load, the Carnot battery mentioned above can be introduced to improve the regulation capability of the coal-fired unit when co-firing sludge, so as to realize that the power generation of sludge co-firing no longer depends on fossil fuels and can achieve efficient conversion of heat and electricity.

[0033] In some implementations, reference Figures 1 to 3As shown, the power generation unit 4 also includes an exhaust gas cooler 450 located between the outlet of the condenser 430 and the heat exchange boiler 410. In this way, the exhaust gas cooler can cool the gas discharged from the heat exchange boiler 410 after heat exchange. Furthermore, the exhaust gas cooler 450 is connected to the low-temperature heat exchanger 3 mentioned in the above embodiment. With the combined action of the exhaust gas cooler 450 and the low-temperature heat exchanger 3, the cooling effect on the gas discharged from the heat exchange boiler 410 can be further improved. (Refer to...) Figure 1 As shown, after the gas from the heat exchange boiler 410 is discharged from the outlet of the heat exchange boiler 410, it can first enter the exhaust cooler 450. At the same time, the gas with a lower temperature discharged from the condenser 430 also enters the exhaust cooler 450. In this way, the gas discharged from the condenser 430 and the gas discharged from the heat exchange boiler 410 will exchange heat. The temperature of the gas discharged from the heat exchange boiler 410 will be cooled down and sent to the low temperature heat exchanger 3 for further cooling, so that the cooled air can be sent back into the compressor 120 for secondary work.

[0034] In some implementations, reference Figures 1 to 3 As shown, the power generation unit 4 also includes a feedwater pump 460 connected to the exhaust gas cooler 450 and the heat exchange boiler 410. In this way, the feedwater pump 460 can pump the gas discharged from the condenser 430 to the heat exchange boiler 410 more quickly for heat exchange, which can improve the heat exchange efficiency of the heat exchange boiler 410 and thus increase the power generation of the turbine 420.

[0035] This disclosure exemplarily describes the operation of a power generation system assembly and a sludge drying energy storage system, which may include, for example, a thermal storage process and a heat exchange process. The operation of the thermal storage process and the heat exchange process will be described in detail below.

[0036] During the heat storage process, the electric motor 110 drives the compressor 120 to work. The compressor 120 draws in outside air and pressurizes and heats it. The high-temperature and high-pressure gas discharged from the outlet of the compressor 120 enters multiple heat storage tanks 131 of the heat storage device 130. When the amount of air stored in the multiple heat storage tanks 131 reaches saturation, the high-temperature and high-pressure gas discharged by the compressor 120 continues to work and directly passes through the heat storage device 130 and enters the drying device 210 of the sludge drying unit 2. The drying device 210 dries the sludge once using high-temperature gas. After drying, the sludge enters the storage device. The sludge is temporarily stored in the storage device 220. When it is necessary to generate electricity for the generator 440 via the turbine 420, the dried sludge is discharged from the storage device 220 and enters the grinding device 230. The dried sludge is ground by the grinding device 230 and then enters the heat exchange boiler 410 for combustion and heat release. The gas condensed in the condenser 430 passes through the exhaust cooler 450 and the feed water pump 460 and then enters the heat exchange boiler 410 to exchange heat with the heat from the combustion of the sludge. After the gas is heated, it is discharged into the turbine 420 to generate electricity, and finally the electrical energy is transmitted to the generator 440 for power generation.

[0037] During the heat release process, high-temperature gas is discharged from multiple heat storage tanks 131 of the heat storage device 130. After the expander 140 expands the turbine and performs work, the gas is discharged into the drying device 210 of the sludge drying unit 2. The drying device 210 uses the expanded high-temperature gas to perform secondary drying of the sludge. After drying, the sludge enters the storage device 220 for temporary storage. When the power generation demand of the turbine 420 increases, i.e., when the load is high, the secondary dried sludge can be discharged through the storage device 220 and enter the grinding device 230 for grinding. The secondary dried sludge after grinding enters the heat exchange boiler 410 for combustion and heat release, releasing more heat. The gas condensed in the condenser 430 enters the heat exchange boiler 410 after passing through the exhaust cooler 450 and the feed water pump 460 to exchange heat with the heat from the combustion of the sludge. After the gas is heated, it is discharged into the turbine 420 to generate electricity. Finally, the electrical energy is transmitted to the generator 440 for power generation.

[0038] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0039] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0040] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A sludge drying and energy storage system, characterized in that, It includes an electric thermal storage unit and a sludge drying unit, among which, The electric thermal storage unit includes an electric motor, a compressor, a thermal storage device, and an expander. The electric motor is connected to the compressor, the compressor is connected to the expander, the inlet of the thermal storage device is connected to the compressor, the outlet of the thermal storage device is connected to the expander and the sludge drying unit, and the outlet of the expander is connected to the sludge drying unit.

2. The sludge drying and energy storage system according to claim 1, characterized in that, The heat storage device includes a plurality of heat storage tanks connected in sequence, and the outlet of at least one of the heat storage tanks is connected to the expander and the sludge drying unit.

3. The sludge drying and energy storage system according to claim 1, characterized in that, The sludge drying unit includes: A drying device is connected to the outlet of the heat storage device and the outlet of the expander; A storage device is connected to the outlet of the drying device; A grinding device is connected to the outlet of the storage device.

4. The sludge drying and energy storage system according to claim 3, characterized in that, The sludge drying unit also includes a filter device that is circulated and connected to the drying device, and the outlet of the filter device is also connected to the inlet of the compressor.

5. The sludge drying and energy storage system according to claim 4, characterized in that, The sludge drying and energy storage system also includes a low-temperature heat exchanger located between the filtration device and the compressor.

6. A control method for a sludge drying and energy storage system, characterized in that, The method is applied to the sludge drying and energy storage system as described in any one of claims 1-5, the method comprising a heat storage process and a heat release process, wherein... The heat storage process includes: an electric motor driving a compressor, the compressor compressing high-temperature gas to heat the heat storage device, and the heat storage device discharging the high-temperature gas to the sludge drying unit; The heat release process includes: the heat storage device discharging the high-temperature gas to the expander, and the expander expanding the high-temperature gas before discharging it to the sludge drying unit.

7. A power generation system assembly, characterized in that, It includes a power generation device and a sludge drying and energy storage system as described in any one of claims 1-5, wherein the outlet of the sludge drying unit of the sludge drying and energy storage system is connected to the power generation device.

8. The power generation system assembly according to claim 7, characterized in that, The power generation device includes: A heat exchange boiler, wherein the inlet of the heat exchange boiler is connected to the outlet of the sludge drying unit, and the outlet of the heat exchange boiler is connected to the compressor; A steam turbine, wherein the steam turbine's air inlet is connected to the heat exchange boiler; A condenser, wherein the condenser's inlet is connected to the turbine's outlet, and the condenser's outlet is connected to the heat exchange boiler; and A generator is connected to the steam turbine.

9. The power generation system assembly according to claim 8, characterized in that, The power generation unit also includes an exhaust cooler located between the condenser outlet and the heat exchange boiler.

10. The power generation system assembly according to claim 9, characterized in that, The power generation device also includes a feedwater pump connected to the exhaust cooler and the heat exchange boiler.

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