阅读说明：本技术 一种基于钢铁厂余热利用的二次储能体系 (Secondary energy storage system based on waste heat utilization of steel plant ) 是由 赵金保 曾静 张彥杰 于 2020-12-31 设计创作，主要内容包括：本发明提供了一种基于钢铁厂余热利用的二次储能体系。所述的储能体系具有高温二次电池和为该高温二次电池进行加热的热源。所述的热源来自于钢铁厂的炼铁工序、炼钢工序、焦化工序和烧结工序的排气余热和固体显热。所述的热源可以为高温二次电池提供至少500℃以上的高温余热。本发明提供的二次储能体系可在电网电能过剩的夜间从电网获取电量进行充电,在电网电能短缺的白天进行放电给电网进行充电,实现对电网的调频。高温二次电池储存的电能也可以提供给钢铁厂的生产作业,从而降低钢铁厂的用电成本。(The invention provides a secondary energy storage system based on waste heat utilization of a steel plant. The energy storage system is provided with a high-temperature secondary battery and a heat source for heating the high-temperature secondary battery. The heat source is from the exhaust waste heat and solid sensible heat of an iron-making process, a steel-making process, a coking process and a sintering process of an iron and steel plant. The heat source can provide high-temperature waste heat of at least more than 500 ℃ for the high-temperature secondary battery. The secondary energy storage system provided by the invention can acquire electric quantity from the power grid for charging at night when the power grid is surplus, and discharge to charge the power grid in the daytime when the power grid is in short supply, so that the frequency modulation of the power grid is realized. The electric energy stored by the high-temperature secondary battery can also be provided for the production operation of the steel plant, thereby reducing the electricity consumption cost of the steel plant.)

1. The utility model provides a secondary energy storage system based on steel plant waste heat utilization which characterized in that: having a high-temperature secondary battery and a heat source for heating the high-temperature secondary battery; the heat source is from the exhaust waste heat and the solid waste heat of an iron-making process, a steel-making process, a coking process and a sintering process of an iron and steel plant; the heat source can provide high-temperature waste heat of at least more than 500 ℃ for the high-temperature secondary battery.

2. The system of claim 1, wherein the blast furnace slag from the ironmaking process flows into the heat energy absorber through a slag bath, the heat absorber is disposed on a flow path of the blast furnace slag, a fluid exchanges heat with the blast furnace slag in the heat absorber, the heated fluid is supplied to the high temperature secondary battery through a pipeline to maintain normal operation of the high temperature secondary battery, and the two heat absorbers alternately supply heat to the high temperature battery.

3. The system of claim 1, wherein the ironmaking process comprises heating a high-temperature secondary battery after a first fluid flows through a blast furnace slag heat absorber and is heated, and then the first fluid passes through a heat exchanger to exchange heat with a second fluid, and the second fluid is high-temperature converter gas or coke oven gas.

4. The system of claim 1, wherein in the step of steel making, the temperature of converter gas is 1550-1700 ℃, and heat in the converter gas is transferred to the fluid by a heat exchanger, so that heated high-temperature fluid is obtained and provided to the high-temperature secondary battery.

5. The system of claim 1, wherein in the iron making process, the blast furnace gas is a byproduct in the production process of the iron making blast furnace, the gas turbine burning the blast furnace gas generates electricity, and the high-temperature flue gas at 500-600 ℃ discharged after the gas turbine is burnt passes through the high-temperature secondary battery to provide a required high-temperature working environment for the high-temperature secondary battery.

6. The system of claim 5, wherein converter gas with a temperature of 1550-1700 ℃ is subjected to heat exchange with flue gas discharged from the gas generator by a heat exchanger and then provided to a high-temperature secondary battery.

Technical Field

The invention relates to a secondary energy storage system based on waste heat utilization, in particular to a secondary energy storage system for providing a heat source for a high-temperature secondary battery by utilizing waste heat of a steel plant.

Technical Field

The chemical power supply can obtain electric energy from the power grid or input electric energy into the power grid according to the actual condition of the public power grid, so that the fluctuation of the power grid is reduced, and the chemical power supply has great application value in maintaining the stable operation of the public power grid. When the public power demand rises and exceeds the basic load in a short period, the chemical power supply can charge the power grid and transmit electric energy to the power grid to meet the demand of users; when the electric energy of the power grid is surplus, the chemical power supply obtains the electric energy from the power grid, the frequency of the power grid is reduced, and the energy is stored in the chemical power supply. Among the chemical power sources described above, a high-temperature battery has proven effective. The sodium-sulfur battery is a high-temperature battery suitable for power grid frequency modulation, and the working temperature is 300-350 ℃. Liquid metal battery (CN103155234) is also considered as a potential chemical power source suitable for grid frequency modulation. Another suitable high temperature battery is the high temperature secondary fuel cell invented in patent (CN 102473987). A hydrogen-producing member made of a metal fuel is provided inside the secondary fuel cell, and can react with water vapor at a high temperature to produce hydrogen gas for the fuel cell to perform a discharge reaction, and can be reduced by charging. The hydrogen-producing fuel and the fuel electrode form a closed space, called an anode chamber, for storing hydrogen and water vapor required by the reaction. In order to make the electrochemical reaction and the chemical reaction between the metal and the fuel smoothly proceed, the battery system needs to be performed under a high temperature condition, and the typical working temperature is 500-1000 ℃. The high temperature operating environment provides the cell with higher energy efficiency. However, to maintain a high temperature environment, sufficient thermal energy needs to be supplied externally. The required thermal energy often needs to be provided by a suitable heating element, which in turn is driven by electricity from the public power grid. The overall efficiency of the high-temperature secondary battery is significantly reduced due to the additional electric power required.

The steel industry is a high-energy-consumption industry, and is a large-power-consumption household, and the power cost is quite high. A large amount of high-temperature exhaust and slag discharge are generated in the production process, and the method has good utilization value. Blast furnace gas is a byproduct in the production process of an iron-making blast furnace, has low heat value, but can be used for generating electricity to generate high-temperature exhaust gas at 500-600 ℃. Blast furnace slag produced in the smelting process of steel has the temperature of about 1450 ℃ and very large latent heat. The temperature of converter gas generated in the converter steelmaking process is 1550-1700 ℃, and the content of CO is 40-80%. The flue gas carries a large amount of latent heat and sensible heat, and has very high utilization value. Meanwhile, the temperature of the steel billet produced in the process is about 900 ℃, and the temperature of the steel slag is about 1550 ℃. In the coking process, the temperature of coke oven gas is about 800 ℃, and the temperature of coke is about 1050 ℃. In the sintering step, the temperature of the sintered ore is about 800 ℃. The typical available waste heat in the steel listed above has the advantages of high waste heat temperature and large heat quantity, and has very high heat utilization value.

Disclosure of Invention

In view of the above background, the present invention is directed to overcome the disadvantages of the prior art, and to reasonably utilize the high-temperature waste heat of the steel plant to maintain the high-temperature environment required by the high-temperature secondary battery, so as to improve the total energy efficiency of the high-temperature secondary battery and the total work efficiency of the steel plant.

The high-temperature waste heat of the steel plant is from waste heat of an iron making process, waste heat of a steel making process, waste heat of a coking process and waste heat of a sintering process. The waste heat of the ironmaking process comes from a blast furnace, preferably from the waste heat of blast furnace gas and blast furnace slag. The waste heat of the steelmaking process is from a converter, preferably from converter gas waste heat, billet waste heat and steel slag waste heat. The waste heat of the coking process is from a coke oven, preferably from the waste heat of coke oven gas and the waste heat of coke. The sintering process residual heat is preferably from sintered ore residual heat.

Preferably, the high-temperature waste heat temperature of the steel plant is more than 500 ℃, and further preferably, the waste heat temperature is more than 600 ℃.

According to different forms of waste heat, different forms of heat are provided for the high-temperature secondary battery by utilizing the waste heat. The above waste heat is divided into solid waste heat and gas waste heat. The solid waste heat comprises blast furnace slag waste heat, steel billet waste heat, steel slag waste heat, coke waste heat, sinter waste heat and the like. The gas waste heat comprises blast furnace gas waste heat, converter gas waste heat, coke oven gas waste heat and the like.

Aiming at the solid waste heat, the utilization mode is to utilize the first fluid to exchange heat with the high-temperature solid. The first fluid comprises a gas and a liquid. After the first fluid is heated by the high-temperature solid, the temperature is increased to obtain the high-temperature first fluid. The high-temperature first fluid is supplied to the high-temperature secondary battery through the pipe to maintain the normal operation of the high-temperature secondary battery. The high-temperature secondary battery has different optimal operating temperatures for different designs. In order to enable the first fluid to maintain the high-temperature secondary battery to work at the optimal working temperature, the purpose can be achieved by selecting a proper first fluid, regulating and controlling the initial temperature and the flow rate of the first fluid and the like according to the difference of the solid waste heat temperatures. Another way to adjust the temperature of the high-temperature first fluid is to exchange heat between the heat in the high-temperature first fluid and the second fluid by using a heat exchanger to transfer the heat, thereby achieving the purpose of adjusting the temperature of the high-temperature first fluid. When the temperature of the high-temperature first fluid is higher than the optimum operating temperature of the high-temperature secondary battery, the temperature of the second fluid is lower than the temperature of the high-temperature first fluid, and heat of the high-temperature first fluid is transferred to the second fluid using the heat exchanger, thereby reducing the temperature of the high-temperature first fluid. The second fluid includes air, other high-temperature exhaust gas of a steel plant, and the like. When the temperature of the high-temperature first fluid is lower than the optimum operating temperature of the high-temperature secondary battery, the temperature of the second fluid is higher than the temperature of the high-temperature first fluid, and heat of the second fluid is transferred to the high-temperature first fluid by means of the heat exchanger, thereby increasing the temperature of the high-temperature first fluid. In this case, the second fluid includes high-temperature exhaust gas from a steel plant. Since the high-temperature first fluid has a very high temperature after heating the high-temperature secondary battery, it can be continuously used by the steam turbine for power generation or for supplying heat to production, living equipment, etc.

For the gas waste heat, two utilization modes are provided. The first gas waste heat utilization mode is to directly provide high-temperature first gas to a high-temperature secondary battery through a pipeline. When the temperature of the high-temperature first gas is higher than the optimal working temperature of the high-temperature secondary battery, the second gas with the temperature lower than that of the high-temperature first gas can be input through the pipeline and mixed with the high-temperature first gas, so that the aim of reducing the temperature of the high-temperature first gas is fulfilled. The second gas comprises other exhaust gas from a steel plant production line, or external gas such as air, nitrogen and the like. When the temperature of the high-temperature first gas is lower than the optimal working temperature of the high-temperature secondary battery, a second gas with the temperature higher than that of the high-temperature first gas, such as other high-temperature exhaust gas of a steel plant, is input through a pipeline so as to achieve the purpose of increasing the temperature. After providing heat for the high-temperature secondary battery, the high-temperature first gas is continuously used for power generation by the steam turbine or supplying heat for production, life and the like.

The second gas waste heat utilization method is to transfer the waste heat of the high-temperature first gas to the second fluid by using the heat exchanger, and provide the heat to the high-temperature secondary battery by using the heated second fluid. The second fluid comprises a gas and a liquid. The kind and flow rate of the fluid are adjusted according to the optimum operating temperature of the high-temperature secondary battery, so as to achieve the purpose of adjusting the high-temperature first gas. The second utilization mode has the advantages that the original gas atmosphere is not destroyed in the waste heat utilization process, and the next utilization of the gas is facilitated. For example, the coke oven gas and the converter gas have higher heat values and high utilization value, and the heat values of the coke oven gas and the converter gas cannot be influenced by introducing other components through the second gas waste heat utilization mode, so that the subsequent continuous utilization is facilitated.

The blast furnace gas is not at a high temperature, but contains CO and H₂Can be applied to power generation. When the blast furnace gas is used for power generation through the gas turbine, the generated exhaust temperature is 500-600 ℃, and the blast furnace gas has great utilization value. The exhaust gas of the gas turbine can effectively realize the heating of the high-temperature secondary battery by the gas waste heat according to the utilization mode of the two gas waste heat.

The utilization modes of the waste heat listed above can be combined in various modes in the practical use process. For example, the utilization of the solid waste heat and the utilization of the gas waste heat are combined, or the utilization of the first gas waste heat and the utilization of the second gas waste heat are combined.

According to the invention, a secondary energy storage system based on waste heat utilization of a steel plant can be provided. The invention maintains the high-temperature working environment of the high-temperature secondary battery by utilizing the waste heat of the iron and steel plant, and can fully utilize the waste heat of the iron and steel plant to improve the energy efficiency of the high-temperature secondary battery. The secondary energy storage system provided by the invention can acquire electric quantity from the power grid for charging at night when the power grid is surplus, and discharge to charge the power grid in the daytime when the power grid is in short supply, so that the frequency modulation of the power grid is realized. The electric energy stored by the high-temperature secondary battery can also be provided for the production operation of the steel plant, thereby reducing the electricity consumption cost of the steel plant.

Drawings

Fig. 1 shows a schematic view of a heat exchange system of embodiment 1.

Fig. 2 shows a schematic view of the heat exchange system of embodiment 2.

Fig. 3 shows a schematic view of the heat exchange system of embodiment 3.

Fig. 4 shows a schematic view of the heat exchange system of example 4.

Fig. 5 shows a schematic view of the heat exchange system of embodiment 5.

Fig. 6 shows a schematic view of the heat exchange system of example 6.

Fig. 7 shows a schematic view of the heat exchange system of example 7.

Fig. 8 shows a schematic view of a heat exchange system of embodiment 8.

FIG. 9 is a schematic diagram of an energy storage system based on waste heat utilization of a steel plant in example 9.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples. The following examples are merely illustrative of the present invention and do not limit the scope of the present invention.

Example 1

Fig. 1 is a schematic diagram of example 1, the temperature of molten iron and blast furnace slag generated in the iron-making process of iron and steel enterprises is about 1450 ℃, the molten iron enters the next steel-making process, and the blast furnace slag retains considerable heat energy. In this embodiment 1, the blast furnace slag may be discharged discontinuously or not continuously at a discharge port, and in this embodiment, the blast furnace slag flows into the thermal energy absorber through the slag groove, the heat absorber is disposed on a flow passage of the blast furnace slag, the fluid exchanges heat with the blast furnace slag in the heat absorber, the heated fluid is supplied to the high-temperature secondary battery through the pipeline, so as to maintain the normal operation of the high-temperature secondary battery, when the blast discharge port does not discharge molten iron and blast furnace slag, a valve of the heat absorber and the secondary battery is closed, and another valve of the heat absorber and the secondary battery discharging molten iron and blast furnace slag is opened. The fluid passes through the high-temperature secondary battery and is used for generating electricity by the steam generator. In the embodiment, the temperature of the first fluid is controlled by adjusting the type of the first fluid and regulating the flow rate of the first fluid and the contact time of the first fluid and the blast furnace slag.

Example 2

Fig. 2 is a schematic view of embodiment 2, and embodiment 2 is a modification of embodiment 1. In contrast to example 1, example 2 can further adjust the operating temperature of the first fluid using the second fluid. The first fluid passes through the blast furnace slag heat absorber to be heated, then passes through the heat exchanger to exchange heat with the second fluid, and then heats the high-temperature secondary battery. After the first fluid is heated to obtain the high-temperature first fluid, when the temperature of the first fluid is lower than the optimal working temperature of the high-temperature secondary battery, the second fluid is higher than the high-temperature first fluid, and the first fluid can exchange heat with the first fluid. Preferably, the second fluid may be converter gas or coke oven gas, the temperature of the converter flue gas being up to 1000 ℃ or more, typically 1600 ℃. When the temperature of the high-temperature first fluid is higher than the optimal working temperature of the high-temperature secondary battery, the temperature of the second fluid is lower than that of the high-temperature first fluid, and the second fluid can be partially led out to be directly combusted to heat the high-temperature secondary battery. Preferably, the first fluid may be air or water vapour.

Example 3

FIG. 3 is a schematic view of example 3; example 3 compared to examples 1 and 2, more emphasis was placed on the combination of high temperature secondary batteries with blast furnace slag processing. The blast furnace slag continuously flows into the blast furnace slag reaction tower through the slag groove. A sliding port is arranged below the blast furnace slag reaction tower, and liquid slag is quantitatively added into a double-roller granulating device for granulation treatment. The granulating fan sprays gas into the reaction tower at high speed, when the granulating slag temperature is reduced to below 700 ℃, the temperature of the heated granulating wind is about 500 ℃, and the granulating wind and the lower circulating hot wind are mixed together by the upper gas collecting pipe and the lower circulating hot wind and enter the dust remover to remove fine granular slag. The large-particle high-temperature granulated slag and the circulating air at the lower part perform countercurrent heat exchange, and the temperature of the circulating air is gradually increased. Finally, discharging slag at the lower part through a slag discharging device; and the temperature of the circulating air rises to about 600-800 ℃, and the circulating air is discharged from a gas collecting pipe at the upper part of the shaft furnace and is converged into a main air outlet pipeline. The dedusted gas passes through a high-temperature secondary battery to provide a high-temperature working environment for the high-temperature secondary battery. The high temperature gas is then used by a steam generator to generate electricity. The temperature of the tail gas discharged by the boiler after heat exchange is lower than 150 ℃, and the tail gas can be blown into the reaction tower through the circulating fan for reutilization.

Example 4

FIG. 4 is a schematic view of example 4; the converter is operated intermittently, one furnace lasts for about 34 minutes, the temperature of converter gas is 1550-1700 ℃, and steel enterprises generally work by staggering a plurality of converters. In example 4, heat from multiple converter gases was transferred to a fluid using a heat exchanger to provide a continuous, uninterrupted source of heat, and a heated, high temperature fluid was obtained and provided to a high temperature secondary battery. The temperature after heat exchange is adjusted by adjusting the kind and flow rate of the fluid according to the optimum operating temperature of the high-temperature secondary battery. Because the temperature of the converter flue gas is as high as more than 1000 ℃, typically 1600 ℃, the temperature of the fluid can be theoretically heated to more than 1000 ℃, and the working temperature requirement of the high-temperature secondary battery at 500-1000 ℃ can be completely met. The high-temperature fluid can be continuously reused by the steam generator after passing through the high-temperature secondary battery. In this embodiment, the heat in the converter gas is utilized without affecting the components of the converter gas, so the converter gas can be subsequently utilized or collected according to the utilization mode of the converter gas in the steel plant.

Example 5

Fig. 5 is a schematic view of embodiment 5, and embodiment 5 is a modification of embodiment 4. According to the characteristic that the converter operates intermittently, example 4 may fail to continuously supply the fluid at a specific temperature to the high-temperature secondary battery due to the suspended discharge of the converter flue gas. Therefore, compared to example 4, this example provides a high-temperature fluid reservoir before the high-temperature secondary battery for storing a certain volume of high-temperature fluid to satisfy continuous normal operation of the high-temperature secondary battery. The mode of operation of this embodiment is as follows: and calculating the required storage amount according to the exhaust duration and the stop time of the converter. And in the period of stopping discharging the converter gas, the heat exchanger does not work. And in the converter gas discharge period, the heat exchanger works to exchange heat to obtain high-temperature fluid. Preferably, the flow rate of the fluid for heat exchange is constant, and the control is convenient. Assuming that the flow rate of the fluid passing through the heat exchanger is v1 and the flow rate of the fluid passing through the high-temperature secondary battery is v2, it is known that v1> v2 according to actual conditions. Therefore, it is necessary to obtain the flow rate through a reasonable calculation so that the amount of fluid stored during the converter gas withdrawal period is sufficient to support the use during the converter gas withdrawal stopping period. The high-temperature fluid can be continuously reused by the steam generator after passing through the high-temperature secondary battery. Since the high temperature fluid exchanges heat with the environment during storage, the temperature of the high temperature fluid needs to be designed to take into account the heat lost therein. To reduce the heat exchange between the high temperature fluid and the environment, the design of the reservoir can be optimized or good heat retention measures can be performed on the reservoir.

Example 6

Fig. 6 is a schematic view of example 6, and example 6 is a modification of example 4, and provides another way for a high-temperature secondary battery to continuously obtain heat. In example 6, the converter gas discharged from the converter was stored in the storage tank and then discharged at a constant flow rate, so that the converter gas in the storage tank can continue to exchange heat with the fluid when the converter stops discharging the converter gas, thereby ensuring continuous operation of the high-temperature secondary battery.

Example 7

FIG. 7 is a schematic diagram of example 7, in which blast furnace gas is a by-product in the production process of an iron-making blast furnace, and can be used for power generation, and when a gas turbine is used for power generation, high-temperature exhaust gas of 500 to 600 ℃ is generated. In example 7, blast furnace gas and coke oven gas were mixed in a certain ratio to form a mixed gas, and sufficient calorific value was obtained to ensure stable combustion of the gas turbine. The coal gas is mixed and enters an electric dust remover to reduce the dust content of the coal gas to below 1mg/m3 so as to meet the requirement of the dust concentration at the inlet of a coal gas compressor (not shown in the figure), and the coal gas enters the coal gas compressor through a coal gas pipeline. High-temperature and high-pressure gas enters the gas turbine through the gas pipeline, the gas and air are mixed and combusted in the gas turbine, and the combusted high-pressure and high-temperature flue gas pushes the impeller to drive the engine to generate power. After the high-temperature flue gas at 500-600 ℃ discharged after the combustion of the gas turbine passes through the high-temperature secondary battery, the high-temperature secondary battery provides a required high-temperature working environment, and then the high-temperature flue gas is utilized by the steam generator to generate electricity. The exhaust gas temperature of the gas turbine can be controlled by regulating and controlling the operating parameters of the gas turbine. In order to ensure that the flue gas discharged from the gas turbine has a sufficient temperature to ensure the normal operation of the high-temperature secondary battery, it is preferable to make the temperature of the flue gas higher than 550 ℃, and more preferably higher than 600 ℃. After the high-temperature secondary battery is heated, the exhaust smoke is continuously used for power generation by the steam generator. In the embodiment, because the blast furnace gas is discharged discontinuously, the mixed gas can be discharged continuously by adjusting the output quantity of the mixed gas, so that the continuous operation of the gas generator, the high-temperature secondary battery and the steam generator is ensured.

Example 8

Fig. 8 is a schematic view of embodiment 8, and embodiment 8 is a combination of embodiment 7 and embodiment 4. The smoke discharged by the gas generator is less than 600 ℃, so that the working temperature requirement of the high-temperature secondary battery cannot be completely met. The temperature of the converter gas is up to 1550-1700 ℃, the exhaust gas temperature of the gas generator can be raised by utilizing the heat exchanger, and the heat required in the process is lower than the energy consumed for directly heating the room temperature fluid to the same temperature. The gas generator is heated by the heat exchanger and then provided for the high-temperature secondary battery. This embodiment can provide a higher temperature for the high-temperature secondary battery than embodiment 7.

Example 9

Fig. 9 is a schematic diagram of an energy storage system based on waste heat utilization of an iron and steel plant, and fig. 9 is a schematic diagram of an energy storage system based on waste heat utilization of an iron and steel plant. The waste heat of the steel plant provides enough heat for the high-temperature secondary battery to ensure the normal work of the high-temperature secondary battery. At night, the electric energy of the public power grid is surplus, and the high-temperature secondary battery obtains the electric energy from the power grid, so that the frequency of the power grid is reduced; and in daytime, the demand of the user on the electric energy is increased, and the high-temperature secondary battery transmits the electric energy to the power grid to meet the demand of the user. In the process, the steel plant can obtain income through the price difference between the electric energy at night and the electric energy in the daytime. Meanwhile, the high-temperature secondary battery can also be used for daily production operation of the steel plant, so that the power consumption cost of the steel plant is greatly reduced.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.