Intermittent high-temperature flue gas waste heat treatment method and device based on steel slag energy storage

Abstract

The invention provides an intermittent high-temperature flue gas waste heat treatment method based on steel slag energy storage, which is applied to a waste heat treatment system, the waste heat treatment system comprises a flue gas main pipeline, a bypass is arranged on the flue gas main pipeline in parallel, an energy storage device is arranged on the bypass, and a gas outlet section of the energy storage device is merged into a gas outlet section of the flue gas main pipeline; the method comprises the steps that the flue gas inlet temperature of a flue gas main pipeline is obtained; when the flue gas inlet temperature is not lower than a first threshold value, a heat storage mode is started, and flue gas of a preset first proportion is shunted to a bypass through the bypass; when the flue gas inlet temperature is not higher than a second threshold value, a heat release mode is started, and all flue gas is switched to a bypass; and when the flue gas inlet temperature is between the first threshold value and the second threshold value, a straight-through adjusting mode is started, and the flow of the flue gas shunted to the bypass is dynamically adjusted through a fuzzy control algorithm. According to the scheme, efficient recovery and large-scale storage of high-temperature flue gas waste heat in the iron and steel industry can be achieved, the flue gas temperature is stabilized, and meanwhile resource utilization of steel slag solid waste is promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial solid waste resource utilization and waste heat recovery and energy storage, and particularly relates to an intermittent high-temperature flue gas waste heat treatment method and device based on steel slag energy storage. BACKGROUND

[0002] The steel industry is a typical high-energy-consumption and high-emission industry, and a large amount of high-temperature flue gas generated in the production process of the steel industry contains rich high-quality waste heat resources. Effective recovery and utilization of this part of waste heat has important significance for energy saving and emission reduction and reduction of production cost.

[0003] However, the high-temperature flue gas generated in the production process of the steel industry (such as converter flue gas temperature of 800-1600 DEG C) has intermittency and volatility, which leads to a decrease in waste heat recovery and power generation efficiency of downstream equipment such as waste heat boilers and power generation systems. The existing waste heat recovery system (such as a waste heat boiler) needs stable high-temperature input to maintain efficiency, and temperature fluctuations will cause the following problems: heat recovery efficiency decreases sharply during low-temperature period, and the system is frequently started and stopped; the equipment is easily damaged by over-temperature during high-temperature period; the energy storage density of the traditional buffer tank is low, and it cannot match the flue gas quality. SUMMARY

[0004] To solve at least one of the above problems, the present application provides an intermittent high-temperature flue gas waste heat treatment method and device based on steel slag energy storage, which has large-scale energy storage capacity, good economy (can utilize solid waste), and high and stable heat exchange efficiency (avoiding blockage and reducing heat transfer temperature difference).

[0005] In a first aspect, the present application provides an intermittent high-temperature flue gas waste heat treatment method based on steel slag energy storage, applied to a waste heat treatment system, wherein the waste heat treatment system comprises a flue gas main pipeline, a bypass is arranged in parallel on the flue gas main pipeline, an energy storage device is arranged on the bypass, and an air outlet section of the energy storage device is connected to an air outlet section of the flue gas main pipeline.

[0006] The method comprises the following steps.

[0007] Obtaining a flue gas inlet temperature of the flue gas main pipeline;

[0008] When the flue gas inlet temperature is not lower than a first threshold value, starting a heat storage mode, and diverting a preset first proportion of the flue gas to the bypass through the bypass;

[0009] When the flue gas inlet temperature is not higher than a second threshold value, starting a heat release mode, and switching all the flue gas to the bypass;

[0010] When the flue gas inlet temperature is between the first threshold value and the second threshold value, starting a straight-through adjustment mode, and dynamically adjusting the flue gas flow rate diverted to the bypass through a fuzzy control algorithm.

[0011] As an optional embodiment, the first threshold value is 500℃, and the second threshold value is 200℃.

[0012] The preset first proportion is 30%-70%.

[0013] As an optional embodiment, when the flue gas inlet temperature is not lower than the first threshold value, the heat storage mode is started, and a preset proportion of the flue gas is shunted to the bypass, including,

[0014] The inner cavity temperature T of the energy storage device is obtained. 储 When the inner cavity temperature T 储 is not lower than the third threshold value, the flue gas flow shunted to the bypass is reduced to a proportion threshold value.

[0015] As an optional embodiment, the inner cavity temperature T of the energy storage device is obtained. 储 When the inner cavity temperature T 储 is not lower than the third threshold value, the flue gas flow shunted to the bypass is reduced to a proportion threshold value, including, when the inner cavity temperature T 储 is not lower than 600℃, it is indicated that the heat storage of the energy storage device is saturated, and the flue gas flow shunted to the bypass is reduced to 30%.

[0016] As an optional embodiment, when the flue gas inlet temperature is not higher than the second threshold value, the heat release mode is started, and all of the flue gas is switched to the bypass; including,

[0017] The inner cavity temperature T of the energy storage device is obtained. 储 When the inner cavity temperature T 储 is not higher than the fourth threshold value, the bypass adjustment mode is switched to, and the heat release mode is closed.

[0018] As an optional embodiment, the inner cavity temperature T of the energy storage device is obtained. 储 When the inner cavity temperature T 储 is not higher than the fourth threshold value, the bypass adjustment mode is switched to, and the heat release mode is closed, including, when the inner cavity temperature T 储 is not higher than 200℃, it is indicated that the heat storage of the energy storage device is exhausted, and the bypass adjustment mode is switched to.

[0019] As an optional embodiment, the bypass adjustment mode is started, and the flue gas flow shunted to the bypass is dynamically adjusted through a fuzzy control algorithm, including, the flue gas outlet temperature of the main flue gas pipeline, the inner cavity temperature T of the energy storage device, 储 the total flue gas flow of the main pipeline, and the bypass flue gas flow are obtained, the bypass target flue gas flow is calculated according to the outlet target temperature, and the opening degree of the bypass inlet adjusting valve is calculated according to the bypass target flue gas flow.

[0020] As an optional embodiment, the method of obtaining the flue gas outlet temperature of the main flue gas duct and the internal temperature T of the energy storage device is described. 储 The total flue gas flow rate of the main pipeline and the bypass flue gas flow rate are calculated based on the target outlet temperature. The fuzzy control dynamic algorithm formula is based on the heat balance of the inlet end, the energy storage device end, and the outlet end.

[0021] A second aspect of this application provides an intermittent high-temperature flue gas waste heat treatment device based on steel slag energy storage, comprising:

[0022] The parameter acquisition module is used to acquire at least the flue gas inlet temperature of the main flue gas duct.

[0023] The comparison module is used to compare the relationship between the flue gas inlet temperature and the first threshold and the second threshold.

[0024] The heat storage mode control module is used to activate the heat storage mode when the flue gas inlet temperature is not lower than a first threshold, and to divert a preset first proportion of the flue gas to the bypass through the bypass.

[0025] The heat release mode control module is used to activate the heat release mode and switch all the flue gas to the bypass when the flue gas inlet temperature is not higher than the second threshold.

[0026] The direct-flow regulation mode control module is used to activate the direct-flow regulation mode when the flue gas inlet temperature is between a first threshold and a second threshold, and to dynamically adjust the flue gas flow rate diverted to the bypass through a fuzzy control algorithm.

[0027] As an optional embodiment, a bypass is connected in parallel to the main flue gas duct, and an energy storage device is installed on the bypass. The outlet section of the energy storage device is connected to the outlet section of the main flue gas duct. The energy storage device includes a main body, which includes a steel structure frame. A refractory material structure is built inside the steel structure frame to surround the inner cavity of the main body. The inner cavity of the main body is filled with composite steel slag energy storage material. A porous support frame is provided at the bottom of the composite steel slag energy storage material. A flue gas outlet and a flue gas inlet are respectively opened at the upper and lower parts of the main body, and an ash outlet is opened at the bottom of the main body.

[0028] This application proposes a method for intermittent high-temperature flue gas waste heat treatment based on steel slag as an energy storage medium and employing direct contact heat exchange. The waste heat treatment system includes a main flue gas pipeline with a bypass connected in parallel. An energy storage device is installed on the bypass, and the outlet section of the energy storage device is connected to the outlet section of the main flue gas pipeline. The method includes: acquiring the flue gas inlet temperature of the main flue gas pipeline; when the flue gas inlet temperature is not lower than a first threshold, activating a heat storage mode and diverting a preset first proportion of the flue gas to the bypass; when the flue gas inlet temperature is not higher than a second threshold, activating a heat release mode and switching all the flue gas to the bypass; when the flue gas inlet temperature is between the first and second thresholds, activating a direct-flow regulation mode and dynamically adjusting the flue gas flow rate diverted to the bypass using a fuzzy control algorithm. By adjusting the bypass flow rate in stages and according to different situations, the bottlenecks of existing technologies can be overcome, enabling efficient recovery, large-scale storage, and stable flue gas temperature of high-temperature flue gas in the steel industry, while promoting the resource utilization of steel slag solid waste. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the flue gas waste heat treatment method provided in the embodiments of this application;

[0031] Figure 2 A schematic diagram of the module structure of the flue gas waste heat treatment device provided in the embodiments of this application;

[0032] Figure 3 A schematic diagram of the waste heat recovery system for the application of the waste heat treatment method for flue gas provided in the embodiments of this application;

[0033] Figure 4 This is a schematic diagram of the structure of the novel energy storage device provided in the embodiments of this application.

[0034] In the diagram: 1. Flue gas outlet; 2. Flue gas inlet; 3. Steel structure frame; 4. Thermal insulation cotton; 5. Refractory material structure; 6. Composite steel slag energy storage material; 7. Porous support frame; 8. Ash outlet; 9. Ash cleaning trolley; 10. Temperature sensor; 11. Fan; 12. Thermocouple and flow meter; 13. Regulating valve. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] This application addresses the problem of temperature and recovery efficiency fluctuations in waste heat recovery systems caused by intermittent high-temperature flue gas generated in steel industry production. By connecting a steel slag energy storage device in parallel to the main flue gas pipeline and combining it with a multi-parameter feedback intelligent control strategy, a stable flue gas temperature output is achieved. The technical solutions provided by various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0037] This application provides an intermittent high-temperature flue gas waste heat treatment method based on steel slag energy storage, which is applied to a waste heat treatment system. The waste heat treatment system includes a main flue gas pipeline, a bypass is connected in parallel on the main flue gas pipeline, an energy storage device is installed on the bypass, and the gas outlet section of the energy storage device is connected to the gas outlet section of the main flue gas pipeline.

[0038] See Figure 1 The method includes:

[0039] Obtain the flue gas inlet temperature of the main flue gas duct;

[0040] When the flue gas inlet temperature is not lower than the first threshold, the heat storage mode is activated, and the flue gas of a preset first proportion is diverted to the bypass through the bypass.

[0041] When the flue gas inlet temperature is not higher than the second threshold, the heat release mode is activated to switch all the flue gas to the bypass.

[0042] When the flue gas inlet temperature is between the first threshold and the second threshold, the direct-flow regulation mode is activated, and the flue gas flow rate diverted to the bypass is dynamically adjusted through a fuzzy control algorithm.

[0043] In one embodiment of this application, the first threshold is 500°C, the second threshold is 200°C, and the preset first ratio is 30%-70%.

[0044] In one embodiment of this application, when the flue gas inlet temperature is not lower than a first threshold, a heat storage mode is activated, and a preset proportion of the flue gas is diverted to the bypass via a bypass, including:

[0045] Obtain the internal temperature T of the energy storage device 储 When the internal cavity temperature T 储 When the flow rate is not lower than the third threshold, the flue gas flow rate diverted to the bypass is reduced to the proportional threshold.

[0046] In one embodiment of this application, the temperature T inside the energy storage device is obtained. 储 When the internal cavity temperature T 储 When the flue gas flow rate diverted to the bypass is not lower than the third threshold, the flow rate is reduced to a proportional threshold, including when the internal cavity temperature T 储 When the temperature is not lower than 600°C, it indicates that the heat storage of the energy storage device is saturated, and the flow rate of the flue gas diverted to the bypass is reduced to 30%.

[0047] In one embodiment of this application, when the flue gas inlet temperature is not higher than a second threshold, a heat release mode is activated to switch all the flue gas to a bypass; including,

[0048] Obtain the internal temperature T of the energy storage device 储 When the internal cavity temperature T 储 When the temperature is not higher than the fourth threshold, switch to direct-flow regulation mode and turn off heat dissipation mode.

[0049] In one embodiment of this application, the temperature T inside the energy storage device is obtained. 储 When the internal cavity temperature T 储 When the temperature is not higher than the fourth threshold, switch to direct-flow regulation mode and turn off heat dissipation mode, including when the internal cavity temperature T 储 When the temperature is not higher than 200℃, it indicates that the heat storage of the energy storage device has been exhausted, and it switches to direct regulation mode.

[0050] In one embodiment of this application, the step of activating the direct-flow adjustment mode and dynamically adjusting the flue gas flow rate diverted to the bypass via a fuzzy control algorithm includes obtaining the flue gas outlet temperature of the main flue gas duct and the internal temperature T of the energy storage device. 储 The total flue gas flow rate of the main pipeline and the flue gas flow rate of the bypass are calculated based on the target outlet temperature. The opening degree of the bypass inlet regulating valve is then calculated based on the target flue gas flow rate of the bypass.

[0051] In one embodiment of this application, the temperature of the flue gas outlet from the main flue gas duct and the temperature T inside the energy storage device are obtained. 储 The total flue gas flow rate of the main pipeline and the bypass flue gas flow rate are calculated based on the target outlet temperature. The fuzzy control dynamic algorithm formula is based on the heat balance of the inlet end, the energy storage device end, and the outlet end.

[0052] In one embodiment of this application, the implementation process and advantages of the method are divided into five sections: ① Parallel system construction and parameter monitoring; ② Multi-mode intelligent switching and execution; ③ Steel slag status linkage control; ④ Stable output of flue gas temperature; ⑤ Dust removal coordination and ash cleaning operation and maintenance.

[0053] The construction and parameter monitoring of the parallel system mentioned above includes: connecting a steel slag energy storage device in parallel to the bypass of the main flue gas pipeline, and installing thermocouples and flow meters 12 at each key node (main pipeline inlet, main pipeline outlet, main pipeline bypass inlet, main pipeline bypass outlet, and points before and after regulating valve 13).

[0054] The second step, intelligent switching and execution of multiple modes, includes: achieving three operating modes as shown in Table 1 by controlling the flow of the regulating valve 13.

[0055] Table 1. Three operating modes (where T represents the air inlet temperature at the main pipeline inlet end).

[0056] Mode Trigger condition Valve action Heat flow direction Heat storage mode T≥500℃ Diversion of high-temperature flue gas to energy storage device Flue gas -> steel slag (heat storage) Heat release mode T≤200℃ Guiding of all flue gas through energy storage device Steel slag -> flue gas (heat release) Straight-through regulation mode 200℃<T<500℃ Fuzzy control algorithm regulation of bypass Partial heat exchange

[0057] Among them, the ③ steel slag state linkage control includes: in the heat storage mode, the temperature sensor 10 monitors the temperature T_storage inside the heat storage device. As an implementation method, the heat storage device is filled with composite steel slag energy storage material 6 as the energy storage material. Therefore, the actual measured temperature is the steel slag temperature T_steel slag. If T_steel slag > 600°C, the diversion ratio is automatically reduced to 30% to prevent heat loss. In the heat release mode, if T_steel slag < 200°C, the system switches to the direct-flow regulation mode and stops heat release.

[0058] Among them, the stable output of flue gas temperature in step ④ includes:

[0059] Thermal storage mode: After the high-temperature flue gas is diverted, the remaining direct flue gas is mixed with the low-temperature flue gas at the device outlet, and the outlet temperature is stabilized at 320℃.

[0060] Exothermic mode: After the low-temperature flue gas is heated by steel slag, the outlet temperature rises from 80℃ to 285℃.

[0061] Among them, ⑤ dust removal coordination and ash cleaning operation and maintenance refers to: self-filtration mechanism, when flue gas penetrates the composite steel slag energy storage material layer 6, dust is intercepted and settled, and the dust removal efficiency is ≥80%; ash cleaning operation, the ash outlet 8 is opened every 72 hours, and the settled ash is transported away by the ash cleaning trolley 9 (the amount of ash cleaning per time is about 20kg / unit).

[0062] In the above embodiments, the following methods are employed: ① A parallel pipeline system is constructed, with thermocouples and flow meters installed at key points to monitor parameters in real time; ② Based on real-time data, the heat storage / heat release / direct flow regulation modes are dynamically switched: when the inlet temperature is ≥500℃, high-temperature flue gas is diverted to heat the steel slag energy storage device; when the inlet temperature is ≤200℃, low-temperature flue gas is introduced into the device to absorb heat and raise its temperature; ③ Dust is removed simultaneously through the dust removal design of the steel slag energy storage device. Ultimately, the outlet flue gas temperature is stabilized at 300±50℃, the efficiency of the waste heat recovery system is improved by more than 40%, and the problems of resource utilization of steel slag solid waste and intermittent heat source peak shaving are solved simultaneously.

[0063] This application provides an intermittent high-temperature flue gas waste heat treatment device based on steel slag energy storage. See [link to relevant documentation]. Figure 2 ,include,

[0064] The parameter acquisition module is used to acquire at least the flue gas inlet temperature of the main flue gas duct.

[0065] The comparison module is used to compare the relationship between the flue gas inlet temperature and the first threshold and the second threshold.

[0066] The heat storage mode control module is used to activate the heat storage mode when the flue gas inlet temperature is not lower than a first threshold, and to divert a preset first proportion of the flue gas to the bypass through the bypass.

[0067] The heat release mode control module is used to activate the heat release mode and switch all the flue gas to the bypass when the flue gas inlet temperature is not higher than the second threshold.

[0068] The direct-flow regulation mode control module is used to activate the direct-flow regulation mode when the flue gas inlet temperature is between a first threshold and a second threshold, and to dynamically adjust the flue gas flow rate diverted to the bypass through a fuzzy control algorithm.

[0069] The processing method of this application is applied to a waste heat recovery system. Embodiments of this application also provide a waste heat recovery system, including a novel energy storage device provided in this application, wherein the energy storage device is embedded in the waste heat recovery system through a pipeline system.

[0070] In one embodiment of this application, see Figure 3 The pipeline system includes a main pipeline, a bypass, and regulating valves 13. The bypass connects to the inlet section of the main pipeline, and the inlet section of the bypass connects to the flue gas inlet 2. The outlet section of the flue gas outlet 1 connects to the outlet section of the main pipeline via the outlet section of the bypass. Multiple regulating valves 13 are installed on the main pipeline and the bypass. The regulating valves 13 are installed at key pipeline nodes and control the flue gas flow rate based on temperature and flow signals, thereby controlling the charging / discharging mode of the steel slag energy storage device. The regulating valves 13 can be manually controlled or electrically controlled; their opening control principle is a common technique in this field and will not be elaborated further.

[0071] In one embodiment of this application, a fan 11 is installed at the air inlet of the main pipeline; thermocouples and flow meters 12 are installed on the main pipeline and the bypass. The fan 11 is located at the front end of the system, providing airflow power to drive the high-temperature flue gas into the steel slag energy storage device. The thermocouples and flow meters 12 integrate temperature and flow monitoring functions, are installed at key nodes of the flue gas pipeline, and provide real-time feedback of flue gas status parameters.

[0072] In the above embodiment, the fan 1 drives the flow of high-temperature flue gas; the intelligent regulating valve 13 controls the flue gas flow rate according to the control requirements, so that the flue gas enters the steel slag energy storage device for heat storage (cooling of high-temperature flue gas) or heat release (heating of low-temperature flue gas); the flue gas after heat exchange is output after being monitored by the temperature and flow meter 12, so as to realize the dynamic control of flue gas temperature.

[0073] In one embodiment of this application, a bypass is connected in parallel to the main flue gas duct, and an energy storage device is installed on the bypass. The outlet section of the energy storage device is connected to the outlet section of the main flue gas duct. See also Figure 4 The energy storage device includes a main body, which includes a steel structure frame 3. The inner side of the steel structure frame 3 is built with a refractory material structure 5 to surround the inner cavity of the main body. The inner cavity of the main body is filled with composite steel slag energy storage material 6. A porous support frame 7 is provided at the bottom of the composite steel slag energy storage material 6. A flue gas outlet 1 and a flue gas inlet 2 are respectively opened at the upper and lower parts of the main body. An ash outlet 8 is opened at the bottom of the main body.

[0074] As a core energy storage medium, composite steel slag energy storage material is mainly composed of steel slag and some inorganic materials. Its main component (steel slag) comes from solid waste in the steel industry, and its usage cost is low.

[0075] The steel frame 3 constitutes the main support structure of the entire device, ensuring its stability. The refractory material structure 5 is built inside the steel frame 3, directly bearing high temperatures and enhancing the device's durability and service life in high-temperature environments. The composite steel slag energy storage material 6 is filled within the space enclosed by the refractory material structure 5. As the core energy storage medium, the composite steel slag energy storage material 6 is mainly composed of steel slag and some inorganic materials. Its main component, steel slag, comes from solid waste in the steel industry, resulting in low usage costs. The porous support frame 7 is located at the bottom of the composite steel slag energy storage material 6, serving a dual function: firstly, supporting the steel slag layer above it; and secondly, allowing the high-temperature flue gas entering the device to penetrate the steel slag layer evenly upwards, avoiding local blockages and reduced heat exchange efficiency caused by uneven airflow distribution.

[0076] The flue gas inlet 2 is located at the lower part or side of the device to introduce high-temperature flue gas; the flue gas outlet 1 is located at the upper part or side of the device to discharge the cooled flue gas, thereby ensuring that the high-temperature flue gas flows from bottom to top through the porous support frame 7 and the composite steel slag energy storage material 6 within the device.

[0077] In one embodiment of this application, the main body further includes a chassis, the porous support frame 7 is disposed above the chassis, and the chassis has a flue gas inlet 2 and an ash outlet 8.

[0078] In one embodiment of this application, the flue gas inlet 2 is a cylindrical opening located in the middle of the chassis, and the cylindrical opening is vertically oriented.

[0079] In one embodiment of this application, multiple ash outlets 8 are arranged along the flue gas inlet 2 and are inclined. The ash outlets 8 are located at the lowest point of the bottom of the device to facilitate the collection and discharge of settled dust.

[0080] In one embodiment of this application, a dust removal trolley 9 is provided below the ash outlet 8 to receive the falling ash. The dust removal trolley 9 is sealed to the ash outlet 8 and is used to collect and remove the dust that settles from the flue gas periodically or continuously.

[0081] In one embodiment of this application, the outer side of the steel structure frame 3 is covered with thermal insulation cotton 4. By tightly wrapping the steel structure frame 3 with the thermal insulation cotton 4, an effective heat insulation layer is formed, which significantly enhances the heat preservation and reduces heat loss during the operation of the device.

[0082] In one embodiment of this application, a temperature sensor 10 for detecting temperature is provided in the inner cavity of the main body. The temperature sensor 10 is installed on the side wall of the device, typically through an opening in the refractory material structure, with its probe pointing towards the composite steel slag energy storage material 6, for real-time monitoring of temperature changes in the steel slag.

[0083] The working process and principle of the steel slag energy storage device and waste heat recovery system mainly include: ① flue gas introduction and direct heat exchange; ② dynamic energy storage and regulation; ③ heat release and heat output; ④ flue gas emission and waste heat utilization; ⑤ ash and slag co-treatment.

[0084] Specifically, ① flue gas introduction and direct heat exchange refers to the high-temperature flue gas generated by the steel plant entering the bottom of the device from the flue gas inlet 2, being evenly distributed by the porous support frame 7, and then penetrating upwards through the composite steel slag energy storage material 6. During this process, the high-temperature flue gas and the steel slag particles undergo direct and sufficient contact heat exchange, the sensible heat in the flue gas is absorbed and stored by the steel slag, and the flue gas temperature decreases accordingly.

[0085] Specifically, the second step, dynamic energy storage control, refers to the temperature sensor 10 continuously monitoring the temperature of the composite steel slag energy storage material 6 and feeding the signal back to the relevant control module. Based on the target energy storage temperature or downstream demand, the heating rate of the steel slag and the final energy storage temperature can be controlled by adjusting the flue gas flow rate entering the device, thereby achieving dynamic control of the energy storage intensity.

[0086] Specifically, ③ heat release and heat energy output refers to closing the high-temperature flue gas passage and introducing low-temperature flue gas or air from the flue gas inlet 2 when heat energy needs to be released. This low-temperature flue gas or air is evenly distributed through the porous support frame 7 and then penetrates upwards through the composite steel slag energy storage material 6, where it is rapidly heated through direct contact with the high-temperature steel slag. The heated high-temperature flue gas or air is then output from the flue gas outlet 1 for user use. The temperature sensor 10 monitors the steel slag temperature in real time and precisely controls the output temperature and heat release power by adjusting the input flow rate until the steel slag temperature drops to the usable lower limit.

[0087] The fourth point, flue gas emission and waste heat utilization, refers to the discharge of flue gas from flue gas outlet 1 after its temperature decreases following heat exchange with steel slag. This cooled flue gas may still contain usable low-temperature waste heat, which can be connected to a downstream waste heat recovery system (such as preheated air or boiler feedwater) for further utilization.

[0088] The fifth step, co-treatment of ash and slag, refers to the effective filtration, interception, and settling of dust particles contained in the high-temperature flue gas as it penetrates the steel slag layer. The settled dust is discharged periodically or continuously through the ash outlet 8 at the bottom and collected and treated by the connected dust removal equipment 9. This process achieves preliminary purification of the flue gas while recovering waste heat.

[0089] The steel slag energy storage device provided in this application is suitable for intermittent high-temperature flue gas waste heat recovery systems in the steel industry. It achieves heat storage through direct contact heat exchange between the composite steel slag energy storage material and the intermittent high-temperature flue gas. During operation, high-temperature flue gas enters the device through the flue gas inlet 2, penetrates the composite steel slag energy storage material 6, and directly contacts it for heat exchange, storing the heat in the steel slag energy storage material 6. A porous support frame 7 is located at the bottom of the composite steel slag energy storage material 6 to support the steel slag layer and evenly guide airflow. A temperature sensor 10 monitors the internal temperature of the device in real time. The cooled flue gas is finally discharged through the flue gas outlet 1. An ash outlet 8 is provided at the bottom of the energy storage device, connected to a dust removal trolley 9 to collect settled dust. This application utilizes the composite steel slag energy storage material 6, whose main component is steel slag, as the energy storage medium, achieving efficient recovery and storage of high-temperature flue gas waste heat, and also has a simultaneous dust removal effect. It is suitable for large-scale waste heat recovery, stabilizing high-temperature flue gas temperature, and peak-shaving energy supply in the steel industry.

[0090] The novel energy storage device and waste heat recovery system based on steel slag as the energy storage medium and employing direct contact heat exchange provided in this application can overcome the bottlenecks of existing technologies, achieving efficient recovery, large-scale storage, and stable flue gas temperature for high-temperature flue gas in the steel industry, while simultaneously promoting the resource utilization of steel slag solid waste. It can achieve:

[0091] 1. Solid waste resource utilization and low-cost energy storage: Innovatively utilize steel slag, a solid waste from the steel industry, to replace traditional expensive sensible heat energy storage materials (such as ceramics, molten salt, etc.), thereby achieving low cost of energy storage media and promoting the resource utilization of steel slag.

[0092] 2. High-efficiency direct contact heat exchange: This method abandons traditional indirect heat exchangers and adopts direct contact heat exchange between flue gas and a steel slag particle bed. This eliminates the thermal resistance and temperature difference losses associated with indirect heat transfer, theoretically achieving the minimum temperature difference between the flue gas and the energy storage medium, thus greatly improving heat exchange efficiency. Simultaneously, the steel slag bed offers relatively low resistance to flue gas flow, and its porous structure makes it less prone to severe blockage compared to tubular heat exchangers.

[0093] 3. Uniform airflow distribution and self-filtration: The coupling design of the porous support frame 7 at the bottom and the composite steel slag energy storage material 6 ensures both stable support of the steel slag layer and uniform distribution of high-temperature flue gas upon entering the energy storage layer, preventing local airflow short-circuiting or blockage. The steel slag bed itself has excellent filtration and adsorption properties for dust in the flue gas.

[0094] 4. Integrated Energy Storage and Dust Removal: While efficiently recovering and storing the waste heat of high-temperature flue gas, this device utilizes the physical filtration effect of the steel slag bed to simultaneously remove most of the dust in the flue gas, achieving synergy between the two functions of "energy storage" and "dust removal" and simplifying the system process.

[0095] 5. Two-way operation and easy switching: The same unit can switch between two operating modes—heat storage (high-temperature flue gas) and heat release (low-temperature air)—by means of valve switching. Heat release is achieved using the existing gas channels and steel slag bed structure, eliminating the need for a separate heat exchanger and significantly reducing system complexity and investment costs.

[0096] The processing method provided in this application has the following technical effects:

[0097] 1. Multi-mode intelligent switching and temperature anchoring mechanism: The first temperature control process based on parallel pipeline structure is used to achieve automatic switching of three operating modes through intelligent regulating valve 13: heat storage mode (inlet ≥ 500℃), heat release mode (inlet ≤ 200℃), and direct regulation mode (200℃ < inlet < 500℃). This stabilizes the output of intermittent high-temperature flue gas from the steel industry to 300±50℃, solving the problem of low waste heat recovery efficiency caused by temperature fluctuations.

[0098] 2. Closed-loop control and energy efficiency leap: Based on fuzzy control algorithm, multiple parameters such as inlet temperature, steel slag temperature and flue gas flow are integrated in real time to dynamically correct valve opening, which significantly improves the stability of outlet temperature and significantly improves the efficiency of waste heat recovery system.

[0099] 3. Dust removal synergy: The steel slag bed self-filters and intercepts ≥80% of dust, reducing the downstream dust removal load by 60%.

[0100] 4. Resource Utilization of Steel Slag Solid Waste: Leveraging the inherent physical properties of steel slag, composite steel slag energy storage materials are prepared through synergistic compounding with other inorganic materials. These materials possess multiple superior characteristics, including high thermal density and excellent cycle stability, making them widely applicable in various energy storage scenarios. This technological approach opens up a new field for the resource utilization of steel slag solid waste, expanding its application boundaries.

[0101] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for treating intermittent high-temperature flue gas waste heat based on steel slag energy storage, characterized in that, The waste heat treatment system includes a main flue gas pipeline, a bypass is connected in parallel on the main flue gas pipeline, an energy storage device is installed on the bypass, and the outlet section of the energy storage device is connected to the outlet section of the main flue gas pipeline. The method includes: Obtain the flue gas inlet temperature of the main flue gas duct; When the flue gas inlet temperature is not lower than the first threshold, the heat storage mode is activated, and the flue gas of a preset first proportion is diverted to the bypass through the bypass. When the flue gas inlet temperature is not higher than the second threshold, the heat release mode is activated to switch all the flue gas to the bypass. When the flue gas inlet temperature is between the first threshold and the second threshold, the direct-flow regulation mode is activated, and the flue gas flow rate diverted to the bypass is dynamically adjusted through a fuzzy control algorithm.

2. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 1, characterized in that, The first threshold is 500°C, and the second threshold is 200°C; The preset first ratio is 30%-70%.

3. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 1, characterized in that, When the flue gas inlet temperature is not lower than a first threshold, the heat storage mode is activated, and a preset proportion of the flue gas is diverted to the bypass via a bypass, including: Obtain the internal temperature T of the energy storage device 储 When the internal cavity temperature T 储 When the flow rate is not lower than the third threshold, the flue gas flow rate diverted to the bypass is reduced to the proportional threshold.

4. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 3, characterized in that, The temperature T inside the energy storage device is obtained. 储 When the internal cavity temperature T 储 When the flue gas flow rate diverted to the bypass is not lower than the third threshold, the flow rate is reduced to a proportional threshold, including when the internal cavity temperature T 储 When the temperature is not lower than 600°C, it indicates that the heat storage of the energy storage device is saturated, and the flow rate of the flue gas diverted to the bypass is reduced to 30%.

5. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 1, characterized in that, When the flue gas inlet temperature is not higher than the second threshold, the heat release mode is activated to switch all the flue gas to the bypass. include, Obtain the internal temperature T of the energy storage device 储 When the internal cavity temperature T 储 When the temperature is not higher than the fourth threshold, switch to direct-flow regulation mode and turn off heat dissipation mode.

6. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 5, characterized in that, The temperature T inside the energy storage device is obtained. 储 When the internal cavity temperature T 储 When the temperature is not higher than the fourth threshold, switch to direct-flow regulation mode and turn off heat dissipation mode, including when the internal cavity temperature T 储 When the temperature is not higher than 200℃, it indicates that the heat storage of the energy storage device has been exhausted, and it switches to direct regulation mode.

7. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 1, characterized in that, The activation of the direct-flow regulation mode, and the dynamic adjustment of the flue gas flow rate diverted to the bypass via a fuzzy control algorithm, includes acquiring the flue gas outlet temperature of the main flue gas duct and the internal temperature T of the energy storage device. 储 The total flue gas flow rate of the main pipeline and the flue gas flow rate of the bypass are calculated based on the target outlet temperature. The opening degree of the bypass inlet regulating valve is then calculated based on the target flue gas flow rate of the bypass.

8. The method for intermittent high-temperature flue gas waste heat treatment based on steel slag energy storage as described in claim 7, characterized in that, The flue gas outlet temperature of the main flue gas duct and the internal temperature T of the energy storage device are obtained. 储 The total flue gas flow rate of the main pipeline and the bypass flue gas flow rate are calculated based on the target outlet temperature. The fuzzy control dynamic algorithm formula is based on the heat balance of the inlet end, the energy storage device end, and the outlet end.

9. An intermittent high-temperature flue gas waste heat treatment device based on steel slag energy storage, characterized in that, include, The parameter acquisition module is used to acquire at least the flue gas inlet temperature of the main flue gas duct. The comparison module is used to compare the relationship between the flue gas inlet temperature and the first threshold and the second threshold. The heat storage mode control module is used to activate the heat storage mode when the flue gas inlet temperature is not lower than a first threshold, and to divert a preset first proportion of the flue gas to the bypass through the bypass. The heat release mode control module is used to activate the heat release mode and switch all the flue gas to the bypass when the flue gas inlet temperature is not higher than the second threshold. The direct-flow regulation mode control module is used to activate the direct-flow regulation mode when the flue gas inlet temperature is between a first threshold and a second threshold, and to dynamically adjust the flue gas flow rate diverted to the bypass through a fuzzy control algorithm.

10. The intermittent high-temperature flue gas waste heat treatment device based on steel slag energy storage as described in claim 9, characterized in that, A bypass is connected in parallel to the main flue gas duct, and an energy storage device is installed on the bypass. The outlet section of the energy storage device is connected to the outlet section of the main flue gas duct. The energy storage device includes a main body, which includes a steel structure frame. The inner cavity of the main body is surrounded by a refractory material structure built inside the steel structure frame. The inner cavity of the main body is filled with composite steel slag energy storage material. A porous support frame is installed at the bottom of the composite steel slag energy storage material. Flue gas outlet and flue gas inlet are respectively opened at the upper and lower parts of the main body, and ash outlet is opened at the bottom of the main body.

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