Compressed-air-storing electricity generating system and electricity generating method using the same

The present invention relates to a compressed air storage power generation system and a power generation method. More specifically, the present invention uses midnight electricity and surplus electricity to inject high-pressure air into a tank buried in the ground to consume electricity. The present invention relates to a compressed air storage power generation system and a power generation method using a compressed air storage power generation system that efficiently manages energy by constantly discharging high-pressure air in a tank to drive a generator during a large amount of time.

Midnight electricity means electricity that is used from 10:00 pm to 8:00 am the next day, or from 11:00 pm to 9:00 am the next day, which is the time when electricity consumption is low. The usage fee is low to supply the surplus electricity produced. Therefore, various methods using midnight electricity are known, and typical devices include a heat storage type midnight electric boiler and a midnight electric water heater that store and use midnight electricity. Such devices are intended to store midnight electricity at night and use the energy stored during the day to disperse power consumption, which is generally biased during the day.

Another method of using midnight electricity is to use midnight electricity to store compressed air in the underground space and supply the stored compressed air to the turbine in the daytime to drive the generator. There are known ways to reduce daytime power consumption.

However, the conventional compressed air storage (CAES) system using midnight electricity produces compressed air compressed by the compressor 20 driven by midnight electricity, as shown in Fig. 4. It is injected into the storage tank 30, and this compressed air is discharged during a time when electricity consumption is high. The discharged compressed air is mixed and burned with fuel in the combustor 50, and the pressure of the burned combustion gas is used to control the turbine 40. It is designed to drive the generator by driving it.

Such a compressed air storage system uses midnight electricity to compress air and convert energy so that it can be used when needed, but it is stored by continuously discharging compressed air. There is a disadvantage that the pressure in the tank 30 is gradually lowered, the pressure of the compressed air discharged is also gradually lowered, and the driving efficiency of the turbine 40 is lowered. Therefore, there is an urgent need for the development of a device capable of continuously discharging the stored compressed air at a constant pressure.

<p> Therefore, the present invention solves the problems of the conventional compressed air storage system as described above, and the storage tanks for storing compressed air are separated into a plurality of storage tanks to form the bottoms of both storage tanks. Connected by a connecting pipe, both storage tanks contain stored water and the internal space is divided by the stored water, so that when air is compressed and stored using midnight electricity, it is connected to the compressor. When compressed air of the desired pressure is injected into the storage tank, the pressure rise is sensed and the water pressure pump attached to the connecting pipe forcibly transfers the stored water to maintain the pressure inside the storage tank at the same time. The other closed second storage tank functions as a pressure accumulator that stores hydraulic energy by compressing the sealed air. In the daytime, the compressed air in one of the storage tanks connected to the turbine is discharged, and the hydraulic pump attached to the connecting pipe senses the pressure decrease and conversely operates as a hydraulic motor to compress the stored water. The pressure in the storage tank is kept constant by supplying it to the storage tank of the above, and at the same time, the hydraulic energy stored in the accumulator is used to generate power via the hydraulic motor.</p><p> Therefore, an object of the present invention is to maintain a constant pressure in the compressed air storage tank during storage and discharge of compressed air by moving the stored water, thereby maximizing the efficiency of the compressor and the turbine. At the same time, power generation using a compressed air storage power generation system and a compressed air storage power generation system that simultaneously realizes an energy storage function that stores hydraulic energy in a pressure accumulator at midnight and uses the stored hydraulic energy to generate power during the day. To provide a method.</p>

<p> The compressed air storage power generation system of the present invention that solves the above-mentioned problems is stored in a compressor that sucks and compresses external air by driving a motor, a storage tank that stores compressed air, and a storage tank. In a compressed air storage power generation system including a compressor that receives compressed air and mixes it with fuel to burn it, and a generator that drives a turbine with the burned gas to generate power by driving the turbine, the storage tank is It is configured separately from the first storage tank and the second storage tank, and the bottom surfaces of the first storage tank and the second storage tank are communicated with each other by a connecting pipe, and the inlet and outlet are on the upper side of the first storage tank. The second storage tank is sealed by forming and inflowing compressed air from the compressor and discharging the compressed air in the storage tank, and flooding the storage water under the first storage tank and the second storage tank. It is characterized in that it is designed to function as a compressor.</p><p> A hydraulic pump / motor mounted on a connecting pipe that connects the first storage tank and the second storage tank forcibly transfers the stored water from the first storage tank to the second storage tank by the pump function, and high pressure by pressure equilibrium. It may be designed to move the stored water from the second storage tank in the state to the first storage tank in the low pressure state.</p><p> Further, the pressure measurement sensor mounted on the first storage tank may be designed to operate the hydraulic pump / motor by comparing the sensing value with the set value.</p><p> When the inside of the first storage tank is at atmospheric pressure, the closed air stored in the second storage tank is set to a pressure higher than the pressure of the compressed air 36 in the first storage tank stored in the atmospheric pressure state. Therefore, the stored water may be designed to be flooded to 90% or more of the total capacity of the first storage tank.</p><p> A second generator may be further attached to the hydraulic pump / motor, and the hydraulic motor may be driven to generate electricity by moving the stored water stored in the second storage tank when the hydraulic motor is activated.</p>

<figref num="1">It is the schematic which showed schematicly the compressed air storage power generation system of this invention.</figref><figref num="2">It is a process diagram which showed the pressure change in the storage tank used in this invention.</figref><figref num="3">It is a process diagram which showed the pressure change in the storage tank used in this invention.</figref><figref num="4">It is a process diagram which showed the pressure change in the storage tank used in this invention.</figref><figref num="5">It is a block diagram of the power generation method using the compressed air storage power generation system of this invention.</figref><figref num="6">It is the schematic which showed the conventional compressed air storage power generation system.</figref>

Hereinafter, the compressed air storage power generation system of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view schematically showing the compressed air storage power generation system of the present invention, and FIGS. 2, 3 and 4 are process diagrams showing the pressure change in the storage tank used in the present invention. , FIG. 5 is a block diagram of a power generation method using the compressed air storage power generation system of the present invention.

As shown in FIG. 1, the compressed air storage power generation system 10 of the present invention includes a compressor 20, a storage tank 30 for storing air compressed by the compressor 20, and compressed air 36 discharged from the storage tank 30. It is equipped with a turbine 40 driven by.

The compressor 20 is designed so that the motor is driven by midnight electricity or excess electricity produced, and the external air is introduced and compressed by the drive of the motor. Such compressors 20 may be designed so that one or more compressors 20 are installed in parallel to reduce the air compression time.

Next, when the storage tank 30 is installed outside or buried in the ground and constructed in a city where buildings are close to each other, it is preferable to bury it in the ground so that the above-ground space can be utilized.

Such a storage tank 30 is basically composed of two, and may be composed of three or more to increase the capacity, or may increase the volume of the tank itself to increase the capacity, if necessary. ..

As shown in the figure, the storage tank 30 is composed of a first storage tank 31 and a second storage tank 32, and the first storage tank 31 has an inflow port 311 that injects compressed air from the compressor 20 into the upper part. And a discharge port 312 for discharging the compressed air 36 inside the tank are formed, and the first storage tank 31 and the second storage tank 32 communicate with each other at the bottom of the first storage tank 31 and the second storage tank 32. A connecting pipe 33 is provided. In addition, a certain amount of stored water 34 is flooded in the lower inner part of the first storage tank 31 and the second storage tank 32, and the flow is performed between the first storage tank 31 and the second storage tank 32. ing. That is, in the closed second storage tank 32, the closed air 35 is located at the upper part, the stored water 34 is located at the lower part, and when the stored water 34 flows in through the connecting pipe 33, the volume of the closed air 35 located at the upper part is reached. It has a function as a pressure accumulator that reduces the pressure and increases the pressure of the closed air 35.

A hydraulic pump / motor 331 that operates a hydraulic pump and conversely operates a hydraulic motor is mounted on the connecting pipe 33 that circulates the stored water 34 described above. For example, at midnight, the hydraulic pump is operated using midnight electricity, the stored water 34 is moved to the second storage tank 32 as much as possible, and the connecting pipe 33 is opened during the daytime when the amount of electricity used is high. The expansion of the closed air 35 in the state moves the stored water 34 stored in the second storage tank 32 to the first storage tank 31, while continuously discharging the compressed air 36 stored in the first storage tank 31. Is designed for. Of course, the above-mentioned hydraulic pump and compressor 20 may use not only the electricity at midnight but also the time when the power consumption is low and the surplus electricity supplied during the daytime.

Further, the compressed air 36 discharged through the discharge port 312 of the first storage tank 31 is mixed with the fuel in the combustor 50 and then burned to drive the turbine 40, and the turbine 40 drives the turbine shaft. Power is generated by a connected generator.

Further, the storage tank 30 may be equipped with a cooler 21 and a regenerator 51 for the inflowing compressed air 36 and the discharged compressed air 36, respectively. Since the compressed air 36 flowing into the storage tank 30 has high heat, the storage capacity can be increased by passing the compressed air 36 through the cooler 21 to reduce the volume and then storing the air. Further, the compressed air 36 to be discharged exchanges heat with the high-temperature exhaust gas discharged from the turbine 40 in the regenerator 51 while passing through the regenerator 51, so that combustion by mixing with fuel is easily performed. Of course, the driving efficiency of the turbine 40 can be increased by bulk expansion.

On the other hand, a pressure measurement sensor 313 is further mounted inside the first storage tank 31. The pressure measurement sensor 313 is designed to detect the pressure in the first storage tank 31 and compare it with the set value to operate the hydraulic pump of the hydraulic pump / motor 331. That is, when the compressor 20 uses the midnight power to store the compressed air 36 of a desired pressure in the first storage tank 31, the pressure measurement sensor 313 detects the pressure rise inside the tank and operates the hydraulic pump. Therefore, the stored water 34 in the first storage tank 31 is forcibly transferred to the second storage tank 32, and the pressure in the first storage tank 31 is maintained constant. On the contrary, when the compressed air 36 of the first storage tank 31 is supplied to the turbine 40 in the daytime, the pressure measurement sensor 313 senses the pressure decrease inside the tank and opens the hydraulic pump / motor 331 to open the second storage. By transferring the stored water 34 in the tank 32 to the first storage tank 31, the pressure in the first storage tank 31 is maintained constant. The hydraulic pump / motor 331 may be configured by a single device as in this embodiment, or the hydraulic pump and the hydraulic motor may be configured separately and installed and used individually. Therefore, the compressed air storage power generation system 10 is designed to further install a control unit for controlling the hydraulic pump and the hydraulic motor so that the hydraulic pump and the hydraulic motor can be smoothly driven.

Further, in the hydraulic pump / motor 331, a second generator 60 is installed on the hydraulic motor shaft, and the water turbine moves the stored water 34 from the second storage tank 32 to the first storage tank 31 by the pressure expansion of the closed air 35. A hydraulic motor with a function is driven to generate power by the second generator 60. That is, the hydraulic pump / motor 331 uses midnight electricity to store hydraulic energy in the second storage tank 32, and during the daytime when power consumption is high, the stored water 34 in the second storage tank 32 is first stored. While moving to the tank 31, the hydraulic motor is driven, power is generated by the second generator 60 of the hydraulic motor shaft, and the stored water 34 moved to the first storage tank 31 keeps the compressed air 36 of the first storage tank 31 constant. It is possible to generate electricity in duplicate by using hydraulic energy and compressed air 36, such as discharging with pressure and driving the turbine 40 to generate electricity.

The pressure change of the storage tank 30 of the compressed air storage power generation system 10 configured as described above will be described in detail with reference to an embodiment. At this time, the description will be made based on the case where the required pressure of the compressed air 36 for driving the turbine 40 is about 50 Bar.

FIG. 2 shows the basic settings before driving the compressed air storage power generation system 10, and the storage water 34 is flooded into the first storage tank 31 in which the inflow port 311 and the discharge port 312 are formed. , The sealed second storage tank 32 contains the sealed air 35, and the first storage tank 31 and the second storage tank 32 are communicated with each other by a connecting pipe 33. A hydraulic pump / motor 331 is mounted on the connecting pipe 33.

At this time, the pressure of the stored water 34 flooded in the first storage tank 31 is 50 Bar, and the pressure of the closed air 35 of the second storage tank 32 is 51 Bar. In this way, the pressure of the closed air 35 in the second storage tank 32 is increased by a certain amount, and when waiting, the stored water is pushed by the pressure of the closed air 35 of the second storage tank 32 as shown in the figure. 34 gather in the first storage tank 31.

As shown in FIG. 3, the compressor 20 is driven by using electricity at midnight in the state of FIG. 2, and compressed air 36 having a pressure of 50 Bar is injected into the first storage tank 31. When the first storage tank 31 is injected with compressed air 36 exceeding the capacity, the pressure rises, and the pressure measurement sensor 313 mounted in the tank detects the pressure rise and operates the hydraulic pump / motor 331. ..

When the hydraulic pump of the hydraulic pump / motor 331 is operated by midnight electricity, the stored water 34 flooded in the first storage tank 31 is forcibly transferred to the second storage tank 32 to reduce the pressure of the first storage tank 31. Reduce to 50 Bar. Further, the closed air 35 and the stored water 34 in the second storage tank 32 gradually have a high pressure, and the stored water 34 flooded in the first storage tank 31 and the second storage tank 32 By the time the water levels are the same, the closed air 35 and the stored water 34 in the second storage tank 32 will each reach 100 Bar.

As shown in FIG. 4, when the hydraulic pump / motor 331 is continuously operated, the stored water 34 moves further and 75% is flooded into the second storage tank 32. When the water level is formed in this way, the volume of the closed air 35 of the second storage tank 32 decreases, and the pressure becomes 200 Bar. Further, the compressor 20 continuously injects compressed air 36 into the first storage tank 31, and 50 Bar of compressed air 36 is received in 75% of the total volume of the first storage tank 31.

On the contrary, in the daytime when a large amount of power consumption is required, the connecting pipe 33 is opened and the pressure equilibrium action due to the pressure difference between the first storage tank 31 and the second storage tank 32 causes the second When the stored water 34 of the storage tank 32 drives the hydraulic pump / motor 331 of the connecting pipe 33, it is moved to the first storage tank 31, and the volume of the moved storage water 34 is moved to the first storage tank 31. The stored compressed air 36 is discharged through the discharge port 312.

More specifically, when the hydraulic pump / motor 331 is opened in the fourth state, the closed air 35 of the second storage tank 32, which has a high pressure, expands to move the stored water 34 to the first storage tank 31 for storage. The 50 Bar of compressed air 36 received in the first storage tank 31 by the movement of the water 34 is discharged through the discharge port 312.

That is, the stored water 34 of the second storage tank 32 is maintained in the first storage tank 31 until the pressure of the closed air 35 of the second storage tank 32 becomes equal to the pressure of the compressed air 36 of the first storage tank 31. The movement is performed, and the movement of the stored water 34 continuously discharges the compressed air 36 stored in the first storage tank 31.

A power generation method using the compressed air storage power generation system 10 of the present invention configured as described above will be described with reference to FIG.

The compressor 20, the first storage tank 31 and the second storage tank 32 whose bottoms are communicated with each other by the connecting pipe 33, and the first storage tank 31 and the second storage tank 32 mounted on the connecting pipe 33. Power generation using a compressed air storage power generation system 10 composed of a hydraulic pump / motor 331 that flows stored water 34 between them and a turbine 40 that is driven by compressed air 36 discharged from the first storage tank 31 to generate power. In the method, the power generation process using the present invention is composed of a compressed air injection stage S1, a pumping stage S2, an discharge stage S3, and a power generation stage S4.

The compressed air injection stage S1 is a stage in which the compressor 20 is driven by using the midnight electricity and the surplus electricity produced, and the compressed air 36 is injected into the first storage tank 31.

Next, in the pumping stage S2, the stored water 34 flooded in the first storage tank 31 is forcibly transferred to the second storage tank 32 by the pump function of the hydraulic pump / motor 331 to seal the second storage tank 32. This is a stage in which the inflow of compressed air 36 using the compressor 20 is increased by pressurizing the air 35 and securing a space in the first storage tank 31.

In the discharge stage S3, the compressed air 36 stored in the first storage tank 31 is discharged to drive the turbine 40, and the hydraulic pump / motor 331 mounted on the connecting pipe 33 is opened to discharge the compressed air 36. This is the stage where the stored water 34 is transferred to the first storage tank 31 by the pressure expansion of the closed air 35 of the second storage tank 32 by the amount of the above.

Further, in order to keep the storage pressure and the discharge pressure of the compressed air 36 of the first storage tank 31 constant, the pressure control stage S5 may be designed to proceed in parallel in the pumping stage S2 and the discharge stage S3. good.

That is, when the compressed air 36 is injected into the first storage tank 31 by the compressor 20, if the amount is more than a certain amount, the pressure of the compressed air 36 in the first storage tank 31 increases. , If the pressure measurement sensor 313 installed in the first storage tank 31 compares the pressure-measured sensing value with the set value input by the user and is greater than or equal to the set value, the pump of the hydraulic pump / motor 331 The function is driven to force the stored water 34 to be pumped to the second storage tank 32.

When the compressed air 36 is used during a time when the power consumption is high, the compressed air 36 in the first storage tank 31 is discharged and the pressure is lowered, so that the pressure measurement sensor 313 measures the sensing value. When the pressure drops by comparing with the set value, the hydraulic pump / motor 331 is opened so that the stored water 34 of the second storage tank 32 is transferred to the first storage tank 31 by the pressure balancing action. The pressure of the compressed air 36 of the first storage tank 31 is maintained constant.

In addition, when the stored water 34 is moved from the second storage tank 32, which is a pressure accumulator, to the first storage tank 31, the stored water 34 drives the motor of the hydraulic pump / motor 331 mounted on the connecting pipe 33, and the water pressure is increased. It is designed so that the hydraulic power generation stage S6, in which the second generator 60 is generated by driving the motor part, is further performed.

Next, in the power generation stage S4, the compressed air 36 discharged in the discharge stage S3 is mixed and burned with the fuel in the combustor 50, and the combustion gas flows into the turbine 40 and collides with the turbine blades to drive the turbine 40. It is the stage to generate electricity.

Further, the compressed air 36 discharged in the discharge stage S3 generates electricity after the heat exchange stage S7 is completed. That is, the discharged compressed air 36 exchanges heat with the high-temperature exhaust gas generated in the turbine 40 while passing through the regenerator 51, and is input to the combustor 50 in a high-temperature state, and heat is applied at this time. The volume of the compressed air 36 is gradually increased, and the volume is rapidly increased at the same time as combustion, so that the output of the turbine 40 is improved.

On the other hand, the examples described as described above are only one embodiment for explaining the present invention. Therefore, it goes without saying that an expert having ordinary knowledge about the technical field to which the present invention belongs also belongs to the technical scope of the present invention when it is partially modified and used with reference to the present embodiment.

As described above, the compressed air storage power generation system and the power generation method using the compressed air storage power generation system of the present invention are configured by separating a plurality of storage tanks for storing compressed air, and the bottoms of both storage tanks. By connecting the storage water with a connecting pipe and enclosing the stored water in both storage tanks to divide the space of both tanks, the hydraulic pump attached to the connecting pipe forcibly transfers the stored water and seals one of them. It is designed to bring the air in the stored storage tank to a high pressure state and inject compressed air at the desired pressure into the other storage tank.

Therefore, when the hydraulic pump / motor mounted on the connecting pipe is opened, the closed air expands due to pressure equilibrium, and the expansion of the closed air moves the stored water to the other storage tank containing compressed air while passing through the hydraulic motor. The other storage tank is designed so that compressed air is discharged to the outside by the volume of the stored water that has been moved.

In the storage tank divided into both spaces in this way, the pressure and amount of compressed air finally discharged by moving the inside of the storage tank in which the stored water is divided according to the compressed state of the air inside. By keeping the temperature constant, the efficiency of the compressor and turbine can be maximized, and at the same time, hydraulic energy is stored in a closed storage tank that functions as a pressure accumulator at midnight, and during the daytime. It will be possible to provide an environment-friendly compressed air storage power generation system and power generation method that can simultaneously exert an energy storage function that uses stored hydraulic energy to generate power.

10 Compressed air storage power generation system 20 Compressor 21 Cooler 30 Storage tank 31 1st storage tank 32 2nd storage tank 33 Connecting pipe 34 Storage water 35 Sealed air 36 Compressed air 40 Turbine 50 Combustor 51 Reproduction machine 60 2nd generator 311 Inflow 312 Discharge port 313 Pressure measurement sensor 331 Hydraulic pump / motor S1 Compressed air injection stage S2 Pumping stage S3 Discharge stage S4 Power generation stage S5 Pressure control stage S6 Hydraulic power generation stage S7 Heat exchange stage