A compressed air energy storage system coupled with waste heat utilization in cement kilns and its operation method

Abstract

This invention discloses a compressed air energy storage system and its operation method for coupled utilization of waste heat from cement kilns. The system comprises a cement kiln waste heat system and a constant-pressure compressed air energy storage system. The cement kiln waste heat system includes a burner, a rotary kiln, a cyclone preheater, and a clinker cooler. The constant-pressure compressed air energy storage system includes a multi-stage compression cooling assembly, a multi-stage heating expansion assembly, a constant-pressure air storage tank, a water turbine, a water storage tank, a hot water tank, and a water pump. This invention, through the organic coupling of the cement kiln waste heat system and the constant-pressure compressed air energy storage system, can efficiently utilize the system's waste heat, reduce energy loss, and improve energy utilization levels, which is of great significance for cement plants to achieve their dual-carbon goals. This invention can also reduce the electricity costs of cement plants. Furthermore, this invention has the advantages of a simple system, mature technology, low investment, and low operating costs.

Description

Technical Field

[0001] This invention belongs to the field of waste heat utilization and energy storage technology, and specifically relates to a compressed air energy storage system and its operation method that couples waste heat utilization of cement kilns. Background Technology

[0002] The cement industry is a high-energy-consuming industry, characterized by high power consumption and high equipment energy consumption. Furthermore, significant energy losses occur during the production process; for example, 30% of the energy input to a rotary cement kiln is lost as waste heat, resulting in substantial energy waste. To reduce energy loss and achieve energy conservation and emission reduction, cement plants generally employ waste heat recovery technology to recover the waste heat discharged from the cement kiln, such as using waste heat boilers to generate electricity, reducing the need for purchased electricity and lowering electricity costs.

[0003] In recent years, cement plants have been installing energy storage systems. These systems store electricity during off-peak hours and release it during peak hours when prices are high, ensuring the plant operates at off-peak rates throughout the day and reducing electricity costs. Furthermore, energy storage systems can serve as emergency power sources for cement plants. In the event of a power outage, the storage system provides emergency power to ensure the supply of power to critical equipment, preventing damage from sudden power failures. In the event of a short-term power shortage, it can support the normal operation of production lines, avoiding production interruptions and economic losses. Therefore, energy storage systems are highly attractive to cement plants.

[0004] Currently, waste heat recovery and energy storage in cement plants are achieved through two independent systems: a waste heat power generation system and an energy storage system. These systems are complex, require large investments, and have high operating costs, requiring further optimization and solutions. Summary of the Invention

[0005] To overcome the problems of complexity, high investment, and high operating costs associated with existing cement plant waste heat recovery and energy storage systems, which involve setting up waste heat power generation and energy storage systems, this invention aims to provide a compressed air energy storage system and its operation method that couples waste heat utilization from cement kilns. During off-peak hours, energy is stored through compressed air; during peak electricity periods with high electricity prices, high-pressure air enters the turbine for expansion and power generation. Simultaneously, waste heat from the cement kiln is used to heat the air, increasing the turbine inlet temperature and power generation capacity, thus simultaneously achieving the goals of waste heat recovery and energy storage. Furthermore, the heat generated during compression is used for heating or producing domestic hot water, further improving the energy utilization efficiency of cement plants.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A compressed air energy storage system coupled with the utilization of waste heat from a cement kiln includes a cement kiln waste heat system and a constant pressure compressed air energy storage system.

[0008] The waste heat system of a cement kiln includes a burner, a rotary kiln, a cyclone preheater, and a clinker cooler, which are connected to the rotary kiln.

[0009] The constant pressure compressed air energy storage system includes a multi-stage compression and cooling assembly, a multi-stage heating and expansion assembly, a constant pressure air storage tank, and a water turbine. The multi-stage compression and cooling assemblies are connected in series. The air-side outlet of the multi-stage compression and cooling assembly is connected to the air-side inlet of the constant pressure air storage tank. The water-side outlet of the constant pressure air storage tank is connected to the inlet of the water turbine. The outlet of the water turbine is connected to the cooling water inlet of the multi-stage compression and cooling assembly. The cooling water outlet of the multi-stage compression and cooling assembly is connected to the air-side inlet of the multi-stage heating and expansion assembly. The air-side outlet of the multi-stage heating and expansion assembly is connected to the air-side inlet of the burner. The heat-side inlet of the multi-stage heating and expansion assembly is connected to the exhaust outlet of the cyclone preheater and the exhaust outlet of the clinker cooler, respectively.

[0010] Furthermore, the cooling water outlet of the multi-stage compression cooling component is divided into two paths: one path is connected to the inlet of the water storage tank, and the other path is connected to the inlet of the hot water tank; the outlet of the water storage tank is connected to the inlet of the water pump, the outlet of the water pump is connected to the water-side inlet of the constant pressure air storage tank, and the air-side outlet of the constant pressure air storage tank is connected to the air-side inlet of the multi-stage heating expansion component.

[0011] Furthermore, the constant pressure air storage tank has a pressure of 8-15 MPa, and the upper part of the constant pressure air storage tank is equipped with an air inlet and an air outlet, while the lower part is equipped with a water inlet and a water outlet; the cooling water in the water storage tank is stored after being cooled by spraying, and the temperature is 15-35℃, and the water storage tank is equipped with a water replenishment inlet.

[0012] Furthermore, the multi-stage compression cooling assembly includes an N-stage compressor and an N-stage cooler, where N is a positive integer and N≥4, and adjacent compressors and coolers are connected in series.

[0013] Furthermore, when N is 4, the N-stage compressor includes a first-stage compressor, a second-stage compressor, a third-stage compressor, and a fourth-stage compressor; the N-stage cooler includes a first-stage cooler, a second-stage cooler, a third-stage cooler, and a fourth-stage cooler; the outlet of the first-stage compressor is connected to the air-side inlet of the first-stage cooler, the air-side outlet of the first-stage cooler is connected to the inlet of the second-stage compressor, the outlet of the second-stage compressor is connected to the air-side inlet of the second-stage cooler, the air-side outlet of the second-stage cooler is connected to the inlet of the third-stage compressor, the outlet of the third-stage compressor is connected to the air-side inlet of the third-stage cooler, the air-side outlet of the third-stage cooler is connected to the inlet of the fourth-stage compressor, the outlet of the fourth-stage compressor is connected to the air-side inlet of the fourth-stage cooler, and the air-side outlet of the fourth-stage cooler is connected to the air-side inlet of the constant-pressure air tank.

[0014] Furthermore, adjacent coolers are connected in parallel on the water side; when N is 4, the N-stage cooler includes a first-stage cooler, a second-stage cooler, a third-stage cooler, and a fourth-stage cooler; the water-side inlets of the first-stage cooler, the second-stage cooler, the third-stage cooler, and the fourth-stage cooler are connected, and the water-side outlets of the first-stage cooler, the second-stage cooler, the third-stage cooler, and the fourth-stage cooler are connected.

[0015] Furthermore, the multi-stage heating expansion assembly includes an M-stage cyclone preheater exhaust gas heater, an M-stage clinker cooler exhaust gas heater, and an M-stage turbine, where M is a positive integer and M≥2. Adjacent cyclone preheater exhaust gas heaters and turbines are connected in series, adjacent clinker cooler exhaust gas heaters and turbines are connected in series, and cyclone preheater exhaust gas heaters and clinker cooler exhaust gas heaters of the same stage are connected in parallel.

[0016] Furthermore, when M is 3, the M-stage cyclone preheater exhaust gas heater includes a first-stage cyclone preheater exhaust gas heater, a second-stage cyclone preheater exhaust gas heater, and a third-stage cyclone preheater exhaust gas heater; the M-stage clinker cooler exhaust gas heater includes a first-stage clinker cooler exhaust gas heater, a second-stage clinker cooler exhaust gas heater, and a third-stage clinker cooler exhaust gas heater; the M-stage turbine includes a first-stage turbine, a second-stage turbine, and a third-stage turbine;

[0017] The air-side outlets of the first-stage cyclone preheater exhaust gas heater and the first-stage clinker cooler exhaust gas heater are respectively connected to the inlet of the first-stage turbine. The first-stage turbine outlet is respectively connected to the air-side inlet of the second-stage cyclone preheater exhaust gas heater and the second-stage clinker cooler exhaust gas heater. The air-side outlets of the second-stage cyclone preheater exhaust gas heater and the second-stage clinker cooler exhaust gas heater are respectively connected to the inlet of the second-stage turbine. The second-stage turbine outlet is respectively connected to the air-side inlet of the third-stage cyclone preheater exhaust gas heater and the third-stage clinker cooler exhaust gas heater. The air-side outlets of the third-stage cyclone preheater exhaust gas heater and the third-stage clinker cooler exhaust gas heater are respectively connected to the inlet of the third-stage turbine. Adjacent cyclones The exhaust gas heaters of the preheaters are connected in parallel on the exhaust gas side, and the exhaust gas inlets of the first-stage cyclone preheater, the second-stage cyclone preheater, and the third-stage cyclone preheater are connected together, as are their exhaust gas outlets. The exhaust gas heaters of the adjacent clinker coolers are connected in parallel on the exhaust gas side, and the exhaust gas inlets of the first-stage clinker cooler, the second-stage clinker cooler, and the third-stage clinker cooler are connected together, as are their exhaust gas outlets.

[0018] Furthermore, each stage of the N-stage compressor has the same pressure ratio, ranging from 1.3 to 2.1, and the outlet temperature of each stage is 60 to 120°C.

[0019] Each stage of the M-class turbine has the same expansion ratio and the same inlet temperature, which is 200–350°C.

[0020] An operation method for a compressed air energy storage system coupled with waste heat utilization in cement kilns includes the following steps:

[0021] During off-peak electricity hours and when electricity prices are low, air is compressed and cooled into low-temperature, high-pressure, high-density air by multi-stage heating and expansion components and multi-stage compression and cooling components, driven by low-priced off-peak electricity. The air then enters a constant-pressure air storage tank for storage. At the same time, the high-pressure water stored in the constant-pressure air storage tank is discharged, thereby realizing the replacement of air and water in the tank and ensuring that the pressure in the air storage tank remains constant. The discharged high-pressure water enters the water turbine to generate electricity, then becomes atmospheric pressure water, and then enters the multi-stage compression and cooling components to cool the air.

[0022] During peak periods and high electricity prices, water is pumped into a constant-pressure air storage tank, driving out the high-pressure air from the tank. The high-pressure air is then split into two streams, which enter the exhaust gas heater of the multi-stage cyclone preheater and the exhaust gas heater of the multi-stage clinker cooler, respectively. After being heated and mixed, the mixture enters the multi-stage turbine to expand and generate electricity. The exhaust gas mixes with the air and carries pulverized coal into the burner for combustion. The resulting high-temperature flue gas flows through the rotary kiln and cyclone preheater to heat and calcine the raw materials. The exhaust gas from the cyclone preheater enters the exhaust gas heater of the multi-stage cyclone preheater to heat the air. After the raw materials are heated and calcined, they become clinker. The air is cooled by the clinker cooler and then enters the exhaust gas heater of the multi-stage clinker cooler to heat the air, thereby recovering waste heat.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. In this invention, the high-temperature waste heat carried by the cyclone preheater exhaust gas and clinker cooler exhaust gas generated by the cement kiln waste heat system is used to heat the air at the turbine inlet, thereby improving the air's work capacity, increasing power generation, recovering waste heat from the cement plant, reducing energy loss, and improving energy utilization.

[0025] 2. The hot water generated by the cooler in this invention can be used for heating in the factory area or as domestic hot water, which can reduce energy loss.

[0026] 3. In this invention, the waste heat system of the cement kiln stores electricity when the electricity price is low and discharges it when the electricity price is high by coupling a constant pressure compressed air energy storage system, which can reduce the electricity cost of cement plants.

[0027] 4. The constant pressure compressed air energy storage system in this invention simultaneously achieves the goals of waste heat recovery from the cement kiln waste heat system and reducing electricity costs, and has the advantages of simple system, low investment, and low operating cost. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the compressed air energy storage system for coupled cement kiln waste heat utilization in this invention.

[0029] In the diagram, 1 is the first-stage compressor, 2 is the first-stage cooler, 3 is the second-stage compressor, 4 is the second-stage cooler, 5 is the third-stage compressor, 6 is the third-stage cooler, 7 is the fourth-stage compressor, 8 is the fourth-stage cooler, 9 is the constant-pressure gas storage tank, 10 is the water turbine, 11 is the water storage tank, 12 is the hot water tank, 13 is the water pump, 14 is the exhaust gas heater of the first-stage cyclone preheater, 15 is the exhaust heater of the first-stage clinker cooler, 16 is the first-stage turbine, 17 is the exhaust gas heater of the second-stage cyclone preheater, 18 is the exhaust heater of the second-stage clinker cooler, 19 is the second-stage turbine, 20 is the exhaust gas heater of the third-stage cyclone preheater, 21 is the exhaust heater of the third-stage clinker cooler, 22 is the third-stage turbine, 23 is the burner, 24 is the rotary kiln, 25 is the cyclone preheater, and 26 is the clinker cooler. Detailed Implementation

[0030] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0031] Furthermore, elements in this invention are referred to as being "fixed to" or "set on" another element, which may be directly on the other element or may also include an intervening element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or may also include an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0032] See Figure 1 A compressed air energy storage system coupled with the utilization of waste heat from a cement kiln includes a cement kiln waste heat system and a constant pressure compressed air energy storage system.

[0033] The waste heat system of the cement kiln includes a burner 23, a rotary kiln 24, a cyclone preheater 25, and a clinker cooler 26. The burner 23, cyclone preheater 25, and clinker cooler 26 are connected to the rotary kiln 24. After the pulverized coal and air mixture is burned in the burner 23, it flows sequentially through the rotary kiln 24 and the cyclone preheater 25 before being discharged. The raw meal is heated and calcined sequentially through the cyclone preheater 25 and the rotary kiln 24 to become clinker, and then cooled by the clinker cooler 26 before being discharged.

[0034] The constant-pressure compressed air energy storage system includes a multi-stage compression and cooling assembly, a multi-stage heating and expansion assembly, a constant-pressure air storage tank 9, a water turbine 10, a water storage tank 11, a hot water tank 12, and a water pump 13. The multi-stage compression and cooling assemblies are connected in series. The air-side outlet of the multi-stage compression and cooling assembly is connected to the air-side inlet of the constant-pressure air storage tank 9. The water-side outlet of the constant-pressure air storage tank 9 is connected to the inlet of the water turbine 10. The outlet of the water turbine 10 is connected to the cooling water inlet of the multi-stage compression and cooling assembly. The cooling water outlet of the multi-stage compression and cooling assembly is divided into two paths, one of which is connected to the water storage tank 12. One inlet is connected to the other, and the other is connected to the inlet of the hot water tank 12; the outlet of the water storage tank 11 is connected to the inlet of the water pump 13, the outlet of the water pump 13 is connected to the water side inlet of the constant pressure air storage tank 9, the air side outlet of the constant pressure air storage tank 9 is connected to the air side inlet of the multi-stage heating expansion component, the air side outlet of the multi-stage heating expansion component is connected to the air side inlet of the burner 23 of the cement kiln waste heat system, and the hot side inlet of the multi-stage heating expansion component is connected to the exhaust outlet of the cyclone preheater 25 and the exhaust outlet of the clinker cooler 26 of the cement kiln waste heat system, respectively.

[0035] The multi-stage compression and cooling assembly includes an N-stage compressor and an N-stage cooler, where N is a positive integer and N≥4. Adjacent compressors and coolers are connected in series. The N-stage compressor includes a first-stage compressor 1, a second-stage compressor 3, a third-stage compressor 5, a fourth-stage compressor 7, ..., the (N-1)th-stage compressor and the Nth-stage compressor.

[0036] The N-stage cooler includes the first-stage cooler 2, the second-stage cooler 4, the third-stage cooler 6, the fourth-stage cooler 8, ..., the N-1th-stage cooler and the Nth-stage cooler.

[0037] The outlet of the first-stage compressor 1 is connected to the air-side inlet of the first-stage cooler 2. The air-side outlet of the first-stage cooler 2 is connected to the inlet of the second-stage compressor 3. The outlet of the second-stage compressor 3 is connected to the air-side inlet of the second-stage cooler 4. The air-side outlet of the second-stage cooler 4 is connected to the inlet of the third-stage compressor 5. The outlet of the third-stage compressor 5 is connected to the air-side inlet of the third-stage cooler 6. The air-side outlet of the third-stage cooler 6 is connected to the inlet of the fourth-stage compressor 7. The outlet of the fourth-stage compressor 7 is connected to the air-side inlet of the fourth-stage cooler 8, and so on, until the outlet of the (N-1)th stage compressor is connected to the air-side inlet of the (N-1)th stage cooler. The air-side outlet of the N-1 stage cooler is connected to the inlet of the N-stage compressor 3, the outlet of the N-stage compressor is connected to the air-side inlet of the N-stage cooler, and the air-side outlet of the N-stage cooler is connected to the air-side inlet of the constant pressure storage tank 9. Adjacent coolers are connected in parallel on the water side. Specifically, the water-side inlets of the first-stage cooler 2, the second-stage cooler 4, the third-stage cooler 6, the fourth-stage cooler 8, ..., the N-1 stage cooler and the N-stage cooler are connected, and the water-side outlets of the first-stage cooler 2, the second-stage cooler 4, the third-stage cooler 6, the fourth-stage cooler 8, ..., the N-1 stage cooler and the N-stage cooler are connected.

[0038] The multi-stage heating and expansion assembly includes an M-stage cyclone preheater exhaust gas heater, an M-stage clinker cooler exhaust heater, and an M-stage turbine, where M is a positive integer and M≥2. Adjacent cyclone preheater exhaust gas heaters and turbines are connected in series, adjacent clinker cooler exhaust heaters and turbines are connected in series, and cyclone preheater exhaust gas heaters and clinker cooler exhaust heaters of the same stage are connected in parallel. Specifically, the M-stage cyclone preheater exhaust gas heater includes a first-stage cyclone preheater exhaust gas heater 14, a second-stage cyclone preheater exhaust gas heater 17, a third-stage cyclone preheater exhaust gas heater 20, ..., an M-1 stage cyclone preheater exhaust gas heater, and an M-stage cyclone preheater exhaust gas heater. The M-stage clinker cooler exhaust heater includes a first-stage clinker cooler exhaust heater 15, a second-stage clinker cooler exhaust heater 18, a third-stage clinker cooler exhaust heater 21, ..., an M-1 stage clinker cooler exhaust heater, and an M-stage clinker cooler exhaust heater. Class M turbines include Class I turbine 16, Class II turbine 19, Class III turbine 22, ..., Class M-1 turbine and Class M turbine.

[0039] The air-side outlets of the first-stage cyclone preheater exhaust gas heater 14 and the first-stage clinker cooler exhaust heater 15 are respectively connected to the inlet of the first-stage turbine 16. The outlet of the first-stage turbine 16 is respectively connected to the air-side inlet of the second-stage cyclone preheater exhaust gas heater 17 and the second-stage clinker cooler exhaust heater 18. The air-side outlets of the second-stage cyclone preheater exhaust gas heater 17 and the second-stage clinker cooler exhaust heater 18 are respectively connected to the inlet of the second-stage turbine 19. The outlet of the second-stage turbine 19 is respectively connected to the air-side inlet of the third-stage cyclone preheater exhaust gas heater 20 and the third-stage clinker cooler exhaust heater 21. The air-side outlets of the exhaust gas heater 20 of the third-stage cyclone preheater and the exhaust gas heater 21 of the third-stage clinker cooler are respectively connected to the inlet of the third-stage turbine 22. The outlet of the third-stage turbine 22 is respectively connected to the air-side inlet of the exhaust gas heater of the fourth-stage cyclone preheater and the exhaust gas heater of the fourth-stage clinker cooler, ..., the air-side outlets of the exhaust gas heater of the M-1 stage cyclone preheater and the exhaust gas heater M-1 of the first-stage clinker cooler are respectively connected to the inlet of the first-stage turbine M-1. The outlet of the M-1 stage turbine is respectively connected to the air-side inlet of the exhaust gas heater of the M-1 stage cyclone preheater and the exhaust gas heater of the M-1 stage clinker cooler, ..., the M-1 stage cyclone preheater... The air-side outlets of the exhaust gas heaters of the first-stage cyclone preheaters and the exhaust gas heaters of the M-stage clinker coolers are respectively connected to the inlet of the M-stage turbine; the exhaust gas heaters of adjacent cyclone preheaters are connected in parallel on the exhaust gas side. The exhaust gas heaters of the first-stage cyclone preheaters 14, 17, 20, ..., and the exhaust gas heaters of the M-1 stage cyclone preheaters are connected to the exhaust gas-side inlets of the M-stage cyclone preheaters. The exhaust gas heater is connected to the exhaust gas side outlet of the exhaust gas heater of the M-stage cyclone preheater; the exhaust gas heaters of adjacent clinker coolers are connected in parallel on the exhaust side, and the exhaust gas heaters of the first-stage clinker cooler 15, the second-stage clinker cooler 18, ..., the M-1-stage clinker cooler and the M-stage clinker cooler are connected to the exhaust gas side inlet, and the exhaust gas heaters of the first-stage clinker cooler 15, the second-stage clinker cooler 18, the third-stage clinker cooler 21, ..., the M-1-stage clinker cooler and the M-stage clinker cooler are connected to the exhaust gas side outlet.

[0040] The N-stage compressor has the same pressure ratio for each stage, ranging from 1.3 to 2.1, and the outlet temperature of each stage is 60 to 120°C.

[0041] Each stage of the M-stage turbine has the same turbine expansion ratio and the same inlet temperature, which is 200–350°C.

[0042] The exhaust outlet of the cyclone preheater 25 is connected to the exhaust gas inlet of the first-stage cyclone preheater exhaust gas heater 14, the second-stage cyclone preheater exhaust gas heater 17, the third-stage cyclone preheater exhaust gas heater 20, ..., the Mth-stage cyclone preheater exhaust gas heater.

[0043] The exhaust outlet of the clinker cooler 26 is connected to the exhaust side inlet of the first-stage clinker cooler exhaust heater 15, the second-stage clinker cooler exhaust heater 18, the third-stage clinker cooler exhaust heater 23, ..., the Mth-stage clinker cooler exhaust heater.

[0044] The constant pressure gas storage tank 9 has a pressure of 8-15 MPa. The upper part of the constant pressure gas storage tank 9 is provided with an air inlet and an air outlet, and the lower part is provided with a water inlet and a water outlet.

[0045] The cooling water in the water storage tank 11 is stored after being cooled by spraying, and the temperature is 15-35℃. The water storage tank 11 is equipped with a water replenishment inlet.

[0046] The present invention provides an operation method for a compressed air energy storage system coupled with waste heat utilization in cement kilns, comprising the following steps:

[0047] During off-peak electricity hours and when electricity prices are low, air is compressed by the first-stage compressor 1 driven by low-priced off-peak electricity. It is then cooled in the first-stage cooler 2, followed by compression by the second-stage compressor 3 and cooling by the second-stage cooler 4, and so on. Finally, after compression by the Nth-stage compressor and cooling by the Nth-stage cooler, it becomes low-temperature, high-pressure, high-density air, which then enters the constant-pressure storage tank 9 for storage. Simultaneously, the high-pressure water previously stored in the constant-pressure storage tank 9 is discharged, thus achieving air and water replacement in the tank and ensuring constant pressure. The discharged high-pressure water enters the turbine 10 to generate electricity, then becomes atmospheric pressure water, which is then divided into N streams and enters the first-stage cooler 2, the second-stage cooler 4, the third-stage cooler 6, the fourth-stage cooler 8, and so on, with the Nth-stage cooler cooling the air. The heated water is divided into two streams: one is stored in the hot water tank 12 for heating the plant area or as domestic hot water, and the other is cooled by spraying and stored in the water storage pool 11. Because water is discharged from the system, it is necessary to replenish the water storage tank 11 regularly.

[0048] During peak periods and high electricity prices, water pump 13 pumps water from storage tank 11 to constant-pressure air storage tank 9, displacing the existing high-pressure air in tank 9. The high-pressure air then splits into two streams, which enter the first-stage cyclone preheater exhaust heater 14 and the first-stage clinker cooler exhaust heater 15, respectively. After being heated and mixed, the mixture enters the first-stage turbine 16 to expand and generate electricity. The exhaust gas then splits into two streams again, entering the second-stage cyclone preheater exhaust heater 17 and the second-stage clinker cooler exhaust heater 18, respectively, and is heated and mixed. After being heated and mixed, the exhaust gas enters the second-stage turbine 19 for expansion and power generation. The exhaust gas is then split into two streams, which enter the exhaust gas heater 20 of the third-stage cyclone preheater and the exhaust gas heater 21 of the third-stage clinker cooler, respectively. After being heated and mixed, the exhaust gas enters the third-stage turbine 22 for expansion and power generation, and so on. The exhaust gas from the (M-1)th stage turbine is again split into two streams, which enter the exhaust gas heater of the Mth-stage cyclone preheater and the exhaust gas heater of the Mth-stage clinker cooler, respectively. After being heated and mixed, the exhaust gas enters the Mth-stage turbine for expansion and power generation. Finally... The air discharged from the first-stage (Mth-stage) turbine still has a relatively high temperature and carries some usable heat. Therefore, after mixing with other air, it carries pulverized coal into burner 23 for combustion. The resulting high-temperature flue gas flows sequentially through rotary kiln 24 and cyclone preheater 25 to heat and calcine the raw materials. The exhaust gas discharged from cyclone preheater 25 has a high temperature and carries a large amount of usable waste heat. Therefore, the exhaust gas enters the first-stage cyclone preheater exhaust gas heater 14, the second-stage cyclone preheater exhaust gas heater 17, and the third-stage cyclone preheater exhaust gas heater 20, respectively. ... The exhaust gas heater of the Mth stage cyclone preheater heats the air, thereby achieving the purpose of recovering waste heat; after the raw material is heated and calcined into clinker, the air is cooled by the clinker cooler 26, and the temperature rises significantly, also carrying a large amount of usable waste heat. If the exhaust gas of the clinker cooler 26 is respectively sent to the exhaust heater of the first stage clinker cooler 15, the exhaust heater of the second stage clinker cooler 18, the exhaust heater of the third stage clinker cooler 21, ... the exhaust heater of the Mth stage clinker cooler to heat the air, the waste heat can be recovered.

[0049] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A compressed air energy storage system coupled to a cement kiln waste heat utilization, characterized in that, The cement kiln waste heat system and the constant pressure compressed air energy storage system are included; The cement kiln waste heat system includes a burner (23), a rotary kiln (24), a cyclone preheater (25) and a clinker cooler (26), the burner (23), the cyclone preheater (25) and the clinker cooler (26) are connected with the rotary kiln (24). The constant pressure compressed air energy storage system includes multi-stage compression cooling assemblies, multi-stage heating expansion assemblies, a constant pressure air tank (9) and a water turbine (10), the multi-stage compression cooling assemblies are connected in series, the air side outlet of the multi-stage compression cooling assemblies is connected with the air side inlet of the constant pressure air tank (9), the water side outlet of the constant pressure air tank (9) is connected with the inlet of the water turbine (10), the outlet of the water turbine (10) is connected with the cooling water inlet of the multi-stage compression cooling assemblies, the cooling water outlet of the multi-stage compression cooling assemblies is connected with the air side inlet of the multi-stage heating expansion assemblies, the air side outlet of the multi-stage heating expansion assemblies is connected with the air side inlet of the burner (23), and the hot side inlets of the multi-stage heating expansion assemblies are respectively connected with the exhaust gas outlet of the cyclone preheater (25) and the exhaust gas outlet of the clinker cooler (26).

2. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 1, characterized in that, The cooling water outlet of the multi-stage compression cooling assemblies is divided into two paths, one path is connected with the inlet of a water storage pool (11), and the other path is connected with the inlet of a hot water tank (12); the outlet of the water storage pool (11) is connected with the inlet of a water pump (13), the outlet of the water pump (13) is connected with the water side inlet of the constant pressure air tank (9), and the air side outlet of the constant pressure air tank (9) is connected with the air side inlet of the multi-stage heating expansion assemblies.

3. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 2, characterized in that, The pressure of the constant pressure air tank (9) is 8-15 MPa, the upper part of the constant pressure air tank (9) is provided with an air inlet and an air outlet, and the lower part of the constant pressure air tank (9) is provided with a water inlet and a water outlet; the cooling water in the water storage pool (11) is stored after being sprayed and cooled, the temperature of the cooling water is 15-35 ℃, and the upper part of the water storage pool (11) is provided with a water supplement inlet.

4. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 1, characterized in that, The multi-stage compression cooling assemblies include N-stage compressors and N-stage coolers, wherein N is a positive integer and N is greater than or equal to 4, and adjacent compressors and coolers are connected in series.

5. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 4, characterized in that, When N is 4, the N-stage compressors include a first-stage compressor (1), a second-stage compressor (3), a third-stage compressor (5) and a fourth-stage compressor (7), the N-stage coolers include a first-stage cooler (2), a second-stage cooler (4), a third-stage cooler (6) and a fourth-stage cooler (8), the outlet of the first-stage compressor (1) is connected with the air side inlet of the first-stage cooler (2), the air side outlet of the first-stage cooler (2) is connected with the inlet of the second-stage compressor (3), the outlet of the second-stage compressor (3) is connected with the air side inlet of the second-stage cooler (4), the air side outlet of the second-stage cooler (4) is connected with the inlet of the third-stage compressor (5), the outlet of the third-stage compressor (5) is connected with the air side inlet of the third-stage cooler (6), the air side outlet of the third-stage cooler (6) is connected with the inlet of the fourth-stage compressor (7), the outlet of the fourth-stage compressor (7) is connected with the air side inlet of the fourth-stage cooler (8), and the air side outlet of the fourth-stage cooler (8) is connected with the air side inlet of the constant pressure air tank (9).

6. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 4, characterized in that, The water sides of the adjacent coolers are connected in parallel; when N is 4, the N-stage cooler comprises a first-stage cooler (2), a second-stage cooler (4), a third-stage cooler (6) and a fourth-stage cooler (8); the water side inlets of the first-stage cooler (2), the second-stage cooler (4), the third-stage cooler (6) and the fourth-stage cooler (8) are connected, and the water side outlets of the first-stage cooler (2), the second-stage cooler (4), the third-stage cooler (6) and the fourth-stage cooler (8) are connected.

7. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 1, wherein, The multi-stage heating expansion assembly comprises M-stage cyclone preheater waste gas heaters, M-stage clinker cooler exhaust gas heaters and M-stage turbines, wherein M is a positive integer and M≥2, adjacent cyclone preheater waste gas heaters and turbines are connected in series, adjacent clinker cooler exhaust gas heaters and turbines are connected in series, and cyclone preheater waste gas heaters and clinker cooler exhaust gas heaters of the same stage are connected in parallel.

8. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 7, characterized in that, When M is 3, the M-stage cyclone preheater waste gas heaters comprise a first-stage cyclone preheater waste gas heater (14), a second-stage cyclone preheater waste gas heater (17) and a third-stage cyclone preheater waste gas heater (20); the M-stage clinker cooler exhaust gas heaters comprise a first-stage clinker cooler exhaust gas heater (15), a second-stage clinker cooler exhaust gas heater (18) and a third-stage clinker cooler exhaust gas heater (21); and the M-stage turbines comprise a first-stage turbine (16), a second-stage turbine (19) and a third-stage turbine (22). The air side outlet of the first stage cyclone preheater waste gas heater (14) and the first stage clinker cooler exhaust gas heater (15) is connected with the inlet of the first stage turbine (16) respectively, the outlet of the first stage turbine (16) is connected with the air side inlet of the second stage cyclone preheater waste gas heater (17) and the second stage clinker cooler exhaust gas heater (18) respectively, the air side outlet of the second stage cyclone preheater waste gas heater (17) and the second stage clinker cooler exhaust gas heater (18) is connected with the inlet of the second stage turbine (19) respectively, the outlet of the second stage turbine (19) is connected with the air side inlet of the third stage cyclone preheater waste gas heater (20) and the third stage clinker cooler exhaust gas heater (21) respectively, the air side outlet of the third stage cyclone preheater waste gas heater (20) and the third stage clinker cooler exhaust gas heater (21) is connected with the inlet of the third stage turbine (22) respectively; the waste gas side of adjacent cyclone preheater waste gas heaters is connected in parallel, the waste gas side inlet of the first stage cyclone preheater waste gas heater (14), the second stage cyclone preheater waste gas heater (17) and the third stage cyclone preheater waste gas heater (20) is connected, the waste gas side outlet of the first stage cyclone preheater waste gas heater (14), the second stage cyclone preheater waste gas heater (17) and the third stage cyclone preheater waste gas heater (20) is connected; the exhaust gas side of adjacent clinker cooler exhaust gas heaters is connected in parallel, the exhaust gas side inlet of the first stage clinker cooler exhaust gas heater (15), the second stage clinker cooler exhaust gas heater (18) and the third stage clinker cooler exhaust gas heater (21) is connected, the exhaust gas side outlet of the first stage clinker cooler exhaust gas heater (15), the second stage clinker cooler exhaust gas heater (18) and the third stage clinker cooler exhaust gas heater (21) is connected.

9. The compressed air energy storage system coupled with a cement kiln waste heat utilization according to claim 1, wherein, The compression ratio of each stage compressor of the N-stage compressor is the same, and the compression ratio is 1.3-2.1, and the outlet temperature of each stage compressor is 60-120℃; The expansion ratio of each stage turbine of the M-stage turbine is the same, and the inlet temperature of each stage turbine is the same, which is 200-350℃.

10. A method for operating a compressed air energy storage system based on the coupled cement kiln waste heat utilization of claim 1, characterized in that, The method comprises the following steps: When the valley electricity or low electricity price, the air is compressed and cooled into low-temperature high-pressure high-density air by the multi-stage heating expansion assembly and the multi-stage compression cooling assembly driven by the low-price valley electricity, and then enters the constant-pressure gas storage tank (9) for storage, at the same time, the high-pressure water stored in the constant-pressure gas storage tank (9) is discharged, so as to realize the replacement of the air and water in the tank and ensure the constant pressure in the gas storage tank (9); the discharged high-pressure water enters the water turbine (10) to generate electricity, and then becomes normal pressure water, and then enters the multi-stage compression cooling assembly to cool the air; In the peak period, high price, the water pump to the constant pressure gas tank (9), and the constant pressure gas tank (9) in the high pressure air drive out, and then the high pressure air into two, respectively into the multistage cyclone preheater exhaust gas heater and multistage clinker cooler exhaust heater, heated to mix, into the multistage turbine expansion work power generation, exhaust gas and air mixture after carrying coal into the burner (23) combustion, the high temperature flue gas generated by the rotary kiln (24) and cyclone preheater (25) on the raw material heating calcination, from the cyclone preheater (25) exhaust gas into the multistage cyclone preheater exhaust gas heater heated air; Raw material heating calcination into clinker, air through the clinker cooler (26) cooling, respectively into the multistage clinker cooler exhaust gas heater (15) heated air, thereby recovering waste heat.

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