Background
In recent years, the energy consumed by heat supply is increased year by year, the difference between peak electricity consumption and valley electricity consumption is gradually enlarged, so that the problem of electric energy waste is increasingly highlighted, a novel energy storage technology needs to be developed for peak clipping and valley filling, the adjusting capacity of a power grid can be greatly improved, and the method has long and profound significance on energy safety, energy conservation and emission reduction in China. Under the practical background of resource waste, the coal-to-gas conversion is a new energy-saving and emission-reduction mode, but a good effect is not achieved, so that a valley electricity heat storage and supply technology needs to be developed. By developing and utilizing the off-peak electricity technology, the whole load of the power grid can be balanced, the power generation efficiency can be obviously improved, the investment of electric power facilities can be greatly saved, the electricity utilization cost can be obviously reduced, and the method has important significance for environmental protection. After governments vigorously encourage coal to change gas, governments in various places have seen a break in encouraging coal to change electricity technology.
At present, the phase-change material has the problem that the stored heat energy is difficult to take out due to low heat conductivity coefficient, and the solid heat storage has the problems of uneven heat storage and difficult control, so that the application of a sensible heat storage technology is seriously limited. The solid particle heat storage material with high temperature resistance and good economical efficiency is a feasible method for solving the problems, and the solid heat storage and supply system of the electric heating fluidized bed has the advantages of low operation cost, high heat storage and release efficiency, convenient control and the like.
In the prior art, for example, the invention patent application with publication number CN107655357A discloses a solid particle heat storage device, which directly utilizes heat-stored solid particles to exchange heat with a working medium of a heat exchanger, and uses the solid particles as a heat exchange fluid to directly participate in the heat exchange of the heat exchanger, and the scheme has the following disadvantages: the solid particle transportation resistance is big, and solid particle erodees the heat exchanger pipe wall and leads to the service life few, and solid particle still need set up the power delivery device who stores hot solid particle's hot storehouse and cold solid particle's cold storehouse, solid particle because the uneven heat transfer efficiency that leads to of distribution is low, and equipment is many, the structure is complicated, wholly leads to the cost-push to and the heat transfer effect is poor.
The problem of poor heating effect also exists in the heating of the electromagnetic coil, and the invention simultaneously solves the technical problem of optimizing the heating effect.
Disclosure of Invention
The invention aims to solve the problems that the stored heat energy is difficult to take out due to low heat conductivity coefficient, the solid heat storage is uneven and difficult to control, the heat exchange structure is complex due to the direct adoption of solid particles, the heat exchange efficiency is low, the service life of a heat exchanger is short and the like of the existing phase-change material, and meanwhile, the phase-change material can be used at the valley peak and balance the load of a power grid. The invention provides an electric heating fluidized bed solid heat storage and supply system, which is characterized in that air rapidly flows to fluidize solid particles, an external heating device utilizes valley electricity to uniformly store heat at high temperature of the solid particles, simultaneously improves the heat exchange efficiency of the solid particles, and supplies heat to users through a heat exchanger by using stored heat. .
The technical scheme of the invention is as follows:
the utility model provides an electrical heating fluidized bed heat accumulator, fluidized bed heat accumulator sets up winding electromagnetic heating coil outward, sets up solid heat accumulation granule in the fluidized bed heat accumulator, electromagnetic heating coil (6) are equipped with to the outside of fluidized bed heat accumulator (2), set up the air inlet room under fluidized bed heat accumulator (2), fluidized bed heat accumulator (2) upper portion sets up out the tuber pipe, and it is more and more big along fluidized bed heat accumulator direction of height electromagnetic heating coil density from supreme down.
Preferably, the coil density increases more and more from bottom to top along the height of the fluidized bed regenerator.
Preferably, the electromagnetic heating coil is arranged at a height H, the density of the lowest end of the electromagnetic heating wire along the height direction is M, and the density M of the electromagnetic heating coil at a distance H from the lowest end of the electromagnetic heating coil is as follows: m + k M (H/H)fWherein f and k are coefficients, and the following requirements are met:
1.15<f<1.25,0.28<k <0.35。
preferably, 1.18< f <1.20,0.30< k < 0.32.
The utility model provides an electrical heating fluidized bed solid heat accumulation and heating system, the system includes fluidized bed heat accumulator (2), heat exchanger (4), heat consumer (5), its characterized in that: the upper part of the fluidized bed heat accumulator (2) is connected with a heat exchanger (4) through an air outlet pipe, the heat exchanger (4) is connected with a heat user (5), an air outlet at the lower part of the heat exchanger is connected with an air return pipe, a bypass vent pipe is connected between the air outlet pipe and the air return pipe, a first adjusting valve is arranged on the bypass vent pipe, and a second adjusting air valve is arranged at the joint of the air outlet pipe and/or the air return pipe and the heat exchanger; the fluidized bed regenerator is the fluidized bed regenerator described above.
Preferably, a gas-solid separation device (3) is arranged at a hot air outlet of the fluidized bed heat accumulator (2).
Preferably, the device comprises a controller, wherein the controller (1) comprises a variable frequency control unit, an operation control unit and a power supply, and the power supply is connected with the electromagnetic heating coil.
Preferably, the solid heat storage particles are at least one of quartz sand, ceramic material particles, magnesium oxide particles, corundum sand and fly ash, and the heat storage temperature is over 600 ℃.
The invention has the following beneficial effects:
1. the coil designed by the invention has the advantages that the distribution density of the coil is changed along the height direction, so that a similar countercurrent heat exchange process is formed by heat exchange, the heat exchange effect is best, and the temperature difference is larger.
2. The optimized coil density distribution change formula enables heat exchange to form a similar countercurrent heat exchange process, so that the heat exchange effect is best, and the temperature difference is larger.
3. The invention can realize heat supply by using valley electricity at night, simultaneously store redundant electric energy in the heat accumulator, and supply heat by using the electric energy stored in the heat accumulator during peak electricity time so as to meet the requirement of saving electric energy.
4. The invention takes air as an intermediate heat exchange medium, and solves the defects of large solid particle transportation resistance, short service life caused by scouring of solid particles on the tube wall of the heat exchanger, low heat exchange efficiency caused by distribution of solid particles, increased cost and poor heat exchange effect of the whole heat exchanger.
5. The invention has the advantages of high heat storage efficiency, high heat exchange efficiency, convenient operation control and low price of the heat storage material, and in the night off-peak electricity stage, the fluidized solid particles are heated by the electric heating technology to store a large amount of heat energy, and in the daytime heat stage, the electric heating device can be closed, and the stored heat energy is used for supplying heat, so that the off-peak electricity utilization rate is improved, the energy utilization efficiency is improved, the problem of incomplete heat release of the traditional solid brick heat storage is solved, and the problem of uneven heat storage of the solid heat storage material is also solved. The invention has the technical advantages of simple structure, high utilization rate of valley electricity, energy saving, environmental protection and convenient operation control.
Detailed Description
Figure 1 shows an electrically heated fluidized bed solids heat storage and supply system. As shown in fig. 1, an electric heating fluidized bed solid heat storage and supply system comprises a fluidized bed heat accumulator 2, a heat exchanger 4, a heat consumer 5, an electromagnetic heating coil 6 and a controller 1, wherein solid heat storage particles are arranged in the heat accumulator 2 as a heat storage working medium, the electromagnetic heating coil 6 is wound and installed on the outer side of the fluidized bed heat accumulator 2 and used for releasing heat to the solid heat storage particles and heating air passing through the solid particles, the electromagnetic heating coil 6 is connected with the controller 1, an air inlet chamber 11 is arranged below the fluidized bed heat accumulator 2, the air inlet chamber 11 is connected with an air return pipe, a variable frequency fan 8 is arranged on the air return pipe, the upper part of the fluidized bed heat accumulator 2 is connected with the heat exchanger 4 through an air outlet pipe, the heat exchanger 4 is connected with the heat consumer 5, an air outlet at the lower part of the heat exchanger 4 is connected with the air return pipe 13, a bypass pipe 12 is arranged between the air outlet pipe and the air return pipe 13, and a first adjusting valve 9 is arranged on the bypass pipe, and a second adjusting air valve 14 is arranged at the joint of the air outlet pipe and/or the air return pipe and the heat exchanger.
In the night valley electricity period, an electromagnetic heating device is started to heat solid particles, a first adjusting air valve 9 of an air return pipeline bypass is started, a second adjusting air valve 14 is closed, the solid particles in the fluidized bed heat accumulator are heated through the electromagnetic heating device, heat energy is stored in the solid particles, meanwhile, air is supplied into the fluidized bed heat accumulator through a fan 8, the solid particles are blown by the air in the fluidized bed heat accumulator, the solid particles are fluidized, heat exchange is carried out with the air, the heat is transferred to the inlet air, and then the inlet air is circulated back to the heat accumulator through a bypass pipeline to continue to carry out heat exchange until the heat is stored in the heat accumulator; and in the peak power period, the first adjusting air valve 9 of the bypass of the air return pipeline is closed, the second adjusting air valve 14 is opened, the electromagnetic heating device is closed, and the heat stored in the solid particles is supplied to a user by utilizing the fluidizing hot air.
Through the technical scheme of this application, can realize utilizing the millet electricity to store unnecessary electric energy in the heat accumulator night, during the peak electricity period, usable unnecessary electric energy supplies heat to reach the needs of practicing thrift the electric energy.
Certainly, as an alternative scheme, in the night valley electricity period, the electromagnetic heating device is started to heat solid particles, when the user also needs heat energy in the night valley electricity period, the first adjusting air valve 9 of the return air pipeline bypass is closed, the second adjusting air valve 14 is opened, the solid particles in the fluidized state in the heat accumulator are heated through the electromagnetic heating device, while the heat energy is stored in the solid particles, the air used for fluidization and heat exchange in the heat accumulator is heated, part of the heat is transferred to the heat user 5 through the heat exchanger through hot air, and the air after heat exchange enters the heat accumulator through the return air pipe to continuously exchange heat; when a user does not need heat energy, the first adjusting air valve 9 of the bypass of the air return pipeline is opened, the second adjusting valve 14 is closed, the solid particles in the heat accumulator are heated through the electric heating device, the heat energy is stored in the solid particles, meanwhile, air is supplied into the heat accumulation device through the fan 8, the air blows the solid particles in the heat accumulator, the solid particles form a fluidized bed shape, and then the solid particles are circulated back to the heat accumulator through the bypass pipeline to be continuously used for fluidization and promoting heat exchange until the heat energy is stored in the heat accumulator. By the scheme, heat storage by electric energy is realized, and whether heat is supplied to a heat user is selected according to needs; and in the peak power period, the first adjusting air valve 9 of the bypass of the air return pipeline is closed, the second adjusting air valve 14 is opened, the electric heating device is closed, and the heat stored in the solid particles is supplied to a user by utilizing the fluidizing hot air.
Through the technical scheme of this application, can realize utilizing the millet electricity to realize the heat supply night, store unnecessary electric energy in the heat accumulator simultaneously, during the peak electricity period, usable unnecessary electric energy supplies heat to reach the needs of practicing thrift the electric energy.
This application is through the heat accumulation technique that utilizes the fluidized bed, can realize the make full use of electric energy, and the loss of the energy is avoided to the abundant heat transfer that carries on.
And an air distribution plate 7 is arranged at the upper part of the air inlet chamber 11. The air distribution plate is provided with a plurality of rows of annular holes. Through setting up the air distribution plate for the air that the air inlet chamber carried the heat accumulator distributes evenly.
Preferably, a gas-solid separation device 3 is arranged at a hot air outlet of the fluidized bed heat accumulator. By arranging the gas-solid separation device, solid particles are prevented from entering the heat exchanger.
The electromagnetic heating coil 6 is connected with the controller 1, the controller 1 comprises a variable frequency control unit, an operation control unit and a power supply, and the power supply is connected with the electromagnetic heating coil.
The gas-solid separation device is a grid which is arranged in the air outlet pipe and used for blocking solid particles, and the air return pipeline is arranged behind the grid.
The heat exchanger 4 is connected with a heat consumer 5, and the heat exchanger 4 is a shell-and-tube heat exchanger.
The heat exchanger 4 is connected with the fluidized bed heat accumulator 2 through an air outlet pipe and a variable frequency fan 8, and the heat exchanger 4 is an air-working medium heat exchange device.
And heat preservation measures are respectively arranged on the fluidized bed heat accumulator 2 and the heat exchanger 4.
The solid particles are quartz sand, ceramic material particles, magnesium oxide particles, corundum sand, coal ash and the like, and the heat storage temperature is over 600 ℃.
The heat exchanger 4 is communicated with an air return pipeline, and the air return pipeline is connected with a variable frequency fan 8.
The variable frequency fan 8 is a device that increases the gas flow rate inside the fluidized bed heat accumulator 2 to fluidize the solid particles.
The electromagnetic heating coil 6 is a device for heating air and solid particles.
The gas-solid separation device 3 is used for separating solid particles in air.
The particle size of the solid particles is determined according to the wind speed and the heat storage capacity.
The variable frequency fan 8 is kept normally open for 24 hours, so that high-temperature gas exchanges heat with the heat exchanger, and the controller 1 controls the power of the electromagnetic heating coil 6 according to the requirement.
During the night off-peak electricity period, the controller 1 starts the electromagnetic heating coil 6 to heat the flowing air and the fluidized solid particles so that a large amount of heat energy is stored.
During the peak time of electricity utilization in daytime, the electromagnetic heating coil 6 is closed, the heat energy stored by the solid particles consumed by flowing air is transferred to the heat exchanger 4, and the heat energy is transferred to a heat user through the heat exchanger 4.
As a preference, the coil density increases from bottom to top along the height of the fluidized bed regenerator. Because in the lower part, the air temperature is the lowest, and is equivalent to the cold source temperature is the lowest, and coil density increases and shows that upper portion heat source temperature is the highest, through the arrangement of cold source heat source temperature antipollution formula for heat transfer forms a similar countercurrent flow heat transfer process in the heat accumulator, and the heat transfer is more effective more abundant, has strengthened whole heat transfer effect. The technical features of the above-mentioned increasing coil density are the results obtained by a large number of experiments and numerical simulations, which are an invention point of the present application, and are not common knowledge in the art.
As a preference, the greater and greater the coil density increases from bottom to top along the height of the fluidized-bed regenerator. Because of through the experiment discovery, through the change that the range increases, above-mentioned setting makes the heat transfer effect best, and the difference in temperature is bigger. This technical feature is the result obtained by a large number of experiments and numerical simulations, and is in accordance with the temperature distribution, which is also an invention point of the present application, and is not common knowledge in the art.
Preferably, the electromagnetic heating coil is arranged at a height H, the density of the lowest end of the electromagnetic heating wire along the height direction is M, and the density M of the electromagnetic heating coil at a distance H from the lowest end of the electromagnetic heating coil is as follows:
m=M+k*M*(h/H)fwherein f and k are coefficients, and the following requirements are met:
1.15<f<1.25,0.28<k <0.35。
preferably, f and k gradually increase as H/H increases.
Preferably, 1.18< f <1.20,0.30< k < 0.32.
The above empirical formula is also a result of a lot of experimental studies, is an optimized structure for the density distribution of the electromagnetic heating coil, is also an invention point of the present application, and is not common knowledge in the field.
The invention has the advantages of high heat storage efficiency, high heat exchange efficiency, convenient operation control and low price of the heat storage material, and in the night off-peak electricity stage, the fluidized solid particles are heated by the electric heating technology to store a large amount of heat energy, and in the daytime heat stage, the heating device can be closed, and the stored heat energy is used for supplying heat, so that the off-peak electricity utilization rate is improved, the energy utilization efficiency is improved, the problem of incomplete heat release of the traditional solid brick heat storage is solved, and the problem of uneven heat storage of the solid heat storage material is also solved.
The invention has the technical advantages of simple structure, high utilization rate of valley electricity, convenient operation control and environmental protection and economy of heat storage materials.
Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.