Converter flue gas heat recovery device

Abstract

The utility model relates to a heat recovery device for converter flue gas, which belongs to the field of flue gas waste heat recovery, and comprises a primary heat exchange mechanism, a secondary heat exchange mechanism, a solid heat storage module and a tail gas emission system, the primary heat exchange mechanism comprises a heat exchange flue and a primary heat exchange pipe network, the heat exchange flue is used for collecting the flue gas, and the secondary heat exchange pipe network is used for collecting the solid heat storage module. The primary heat exchange pipe network is arranged in the heat exchange flue and used for primary heat exchange of smoke, and the primary heat exchange pipe network and the solid heat storage module are connected to form heat exchange medium circulation. The secondary heat exchange mechanism comprises one or more hearths arranged in parallel, an oxygen combustion-supporting fan and a secondary heat exchange pipe network, flue gas after primary heat exchange enters the hearths, the oxygen combustion-supporting fan is communicated with the hearths through an oxygen pipeline, burners are arranged in the hearths and used for oxygen blowing combustion of the flue gas, and the secondary heat exchange pipe network is communicated with the secondary heat exchange pipe network. The secondary heat exchange pipe network is arranged in the hearth and used for secondary heat exchange of high-temperature flue gas after combustion, and the secondary heat exchange pipe network and the solid heat storage module are connected to form heat exchange medium circulation. And more efficient heat energy recovery is realized according to the characteristics of the converter flue gas.

Description

Technical Field

[0001] This utility model belongs to the field of flue gas recovery, specifically relating to a heat recovery device for converter flue gas. Background Technology

[0002] A converter is a metallurgical furnace that uses blown-in air, pure oxygen, etc., to oxidize impurities in liquid gas and generate the required heat energy. The temperature of converter flue gas reaches over 1200℃, and the carbon monoxide content in the flue gas is high. Direct emission of converter flue gas would result in significant waste of heat energy and environmental harm. Converter waste heat recovery is an important development direction for the industry. There are many publicly available documents on converter waste heat recovery, such as patent publication number CN 115096101 A, which discloses a high-efficiency power generation system for molten salt energy storage of converter waste heat, relating to the fields of converter steelmaking waste heat recovery and waste heat power generation. This invention is a complete system from the steelmaking converter outlet flue to waste heat power generation, mainly including a flue gas system, a combustion air system, a molten salt thermal storage system, a steam-water power generation system, and a desulfurization, denitrification, and dust removal flue gas purification system. This invention improves both the recovery rate and sensible heat utilization rate of converter gas. Combined with a high-efficiency power generation system, it significantly enhances energy recovery and utilization efficiency, reduces energy consumption in the converter steelmaking process of steel enterprises, and also reduces pollution and environmental operating costs, greatly lowering the energy and environmental costs of converter steelmaking. This technical solution uses air for combustion, which increases the nitrogen oxide content in the flue gas, significantly increases the flue gas volume, and decreases the temperature. Considering the intermittent oxygen blowing characteristics of converter smelting, the converter flue gas is also discontinuous, with significant fluctuations in composition and temperature over time. Therefore, developing more efficient converter flue gas heat recovery technologies remains a direction of effort for those skilled in the art. Summary of the Invention

[0003] The purpose of this invention is to provide a heat recovery device for converter flue gas, which combines a solid heat storage body to achieve high-efficiency heat recovery of converter flue gas.

[0004] The technical solution adopted by this utility model to solve the above problems is as follows: a heat recovery device for converter flue gas, including a primary heat exchange mechanism, a secondary heat exchange mechanism, a solid heat storage module, and a tail gas emission system. The primary heat exchange mechanism includes a heat exchange flue and a primary heat exchange pipe network. The heat exchange flue is used to collect flue gas, and the primary heat exchange pipe network is arranged in the heat exchange flue for primary heat exchange of the flue gas. The primary heat exchange pipe network is connected to the solid heat storage module and forms a medium circulation. The secondary heat exchange mechanism includes one or more furnaces, an oxygen combustion fan, and a secondary heat exchange pipe network arranged in parallel. The heat exchange flue is connected to the furnace, and the flue gas after primary heat exchange enters the furnace. The oxygen combustion fan is connected to the furnace through an oxygen pipeline. Burners are installed in the furnace for oxygen combustion of the flue gas. The secondary heat exchange pipe network is arranged in the furnace for secondary heat exchange of the high-temperature flue gas after combustion. The secondary heat exchange pipe network is connected to the solid heat storage module and forms a medium circulation.

[0005] Preferably, a switching valve is provided between the heat exchange flue and the furnace.

[0006] Preferably, the solid thermal energy storage module includes a primary solid thermal energy storage module and a secondary solid thermal energy storage module, wherein the primary solid thermal energy storage module is connected to the primary heat exchange network and the secondary solid thermal energy storage module is connected to the secondary heat exchange network.

[0007] Preferably, an upper air regulating plate and a lower air regulating plate are provided inside the furnace. The burner is located below the upper air regulating plate, and the lower air regulating plate is located below the burner. These are used to balance the flue gas in the furnace, which helps to ensure complete combustion. The secondary heat exchange network is located below the lower air regulating plate. The high-temperature flue gas generated after combustion undergoes secondary heat exchange.

[0008] Preferably, the secondary heat exchange mechanism further includes an oxygen preheating chamber, through which the oxygen pipeline passes, and the flue gas preheats the oxygen in the oxygen pipeline when it flows through the oxygen preheating chamber.

[0009] Preferably, the exhaust gas emission system includes one or more of the following: desulfurization and denitrification equipment, steam boiler drum, dust removal equipment, and carbon dioxide capture equipment. The steam boiler drum generally refers to a low-pressure steam boiler drum, used to further utilize the waste heat in the exhaust gas.

[0010] Compared with existing technologies, the advantages of this utility model are as follows: Based on the intermittent oxygen blowing production method of converter smelting, where the flow rate and composition of converter flue gas exhibit periodic fluctuations, this application designs a new heat recovery device. This device mainly consists of a primary heat exchange mechanism, a secondary heat exchange mechanism, and a solid energy storage module. The primary and secondary heat exchanges are relatively independent. The secondary heat exchange is performed on the flue gas after combustion. Before both heat exchanges, the flue gas temperature is as high as 1200-1400℃. After the primary heat exchange, the flue gas temperature decreases to 800-1000℃, and after the secondary heat exchange, the flue gas temperature decreases to 300℃. Using steam as the heat exchange medium, high-grade, high-temperature steam is obtained after both heat exchanges. The high-temperature steam enters the solid energy storage module to store heat, and the low-temperature steam after heat exchange re-enters the heat exchange network to form a heat exchange cycle. This application achieves more efficient heat recovery of converter flue gas. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the converter flue gas heat recovery device in an embodiment of this utility model;

[0012] Figure 2 This is a partial structural diagram of the secondary heat exchanger in the device according to an embodiment of the present invention;

[0013] In the diagram, 1 is the converter, 201 is the heat exchange flue, 202 is the primary heat exchange pipeline, 203 is the switching valve, 301 is the furnace, 302 is the oxygen preheating chamber, 303 is the oxygen combustion fan, 304 is the secondary heat exchange pipeline, 305 is the upper air adjustment plate, 306 is the burner, 307 is the lower air adjustment plate, 401 is the primary solid heat storage module, and 402 is the secondary solid heat storage module. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to the accompanying drawings. The embodiments described are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. The textual descriptions in this embodiment correspond to the accompanying drawings, and the descriptions involving orientation are also based on the descriptions in the accompanying drawings, and should not be construed as limiting the scope of protection of the present invention.

[0015] like Figure 1 As shown, the converter flue gas heat recovery device in this embodiment includes a primary heat exchange mechanism, a secondary heat exchange mechanism, a solid heat storage module, and a tail gas emission system. Their structures and functions are described in detail below:

[0016] The primary heat exchange mechanism includes a heat exchange flue 201 and a primary heat exchange network 202. The heat exchange flue 201 is used to collect the exhaust gas from the converter smelting. The temperature of the flue gas in the flue is as high as 1200-1400℃. The primary heat exchange network 202 is arranged in the heat exchange flue 201 and uses low-temperature steam as the heat exchange medium for the primary heat exchange of the flue gas. The primary heat exchange network 202 is connected to the primary solid heat storage module 401 and forms a circulation of the heat exchange medium.

[0017] The secondary heat exchange mechanism includes multiple parallel furnaces 301, an oxygen combustion-supporting fan 303, a secondary heat exchange pipeline network 304, and an oxygen preheating chamber 302. The heat exchange flue is connected to each furnace, and a switching valve 203 is installed between the heat exchange flue 201 and the furnace 301. The flue gas after primary heat exchange enters the furnace 301 for re-combustion. Burners 306 are installed inside the furnace 301. The oxygen combustion-supporting fan 303 is connected to the furnace 301 via an oxygen pipeline. The flue gas is injected through the burners and undergoes pre-oxygenation combustion within the furnace. To balance the flue gas in the furnace, an upper air regulating plate 305 and a lower air regulating plate 307 are installed in the furnace 301. The burner 306 is located below the upper air regulating plate 305, and the lower air regulating plate 307 is located below the secondary heat exchange pipe network 304. The burner's spray direction is downward. The area above the lower air regulating plate 307 is the flame combustion zone and the secondary heat exchange zone. The high-temperature flue gas generated after combustion reaches a temperature of 1200-1400℃ and undergoes secondary heat exchange with the medium in the secondary heat exchange pipe network. The secondary heat exchange pipe network 304 is connected to the secondary solid heat storage module 402 and forms a heat exchange medium circulation. The oxygen pipeline passes through the oxygen preheating chamber, where the exhaust gas after heat exchange preheats the combustion oxygen in the oxygen pipeline, increasing the calorific value of combustion.

[0018] The solid thermal energy storage module includes a primary solid thermal energy storage module 401 and a secondary solid thermal energy storage module 402, which are used to store converter flue gas and waste heat after combustion, respectively, to realize energy storage and reuse.

[0019] The exhaust gas emission system includes desulfurization and denitrification equipment, a steam boiler, dust removal equipment, carbon dioxide capture equipment, and an emission chimney. The steam boiler further absorbs the waste heat in the exhaust gas, the carbon dioxide capture equipment replenishes the carbon dioxide in the exhaust gas, and finally the purified exhaust gas is released through the emission chimney.

[0020] In this embodiment, the high-temperature steam generated by the primary and secondary heat exchange can be used to perform external work directly, such as generating electricity, or it can enter the solid thermal storage module for thermal energy storage and perform external work as needed in the form of high-temperature steam.

Claims

1. A heat recovery device for converter flue gas, characterized in that: The system includes a primary heat exchange mechanism, a secondary heat exchange mechanism, a solid thermal storage module, and a tail gas emission system. The primary heat exchange mechanism includes a heat exchange flue and a primary heat exchange pipe network. The heat exchange flue is used to collect flue gas, and the primary heat exchange pipe network is arranged within the heat exchange flue for primary heat exchange of the flue gas. The primary heat exchange pipe network is connected to the solid thermal storage module and forms a heat exchange medium circulation. The secondary heat exchange mechanism includes one or more parallel furnace chambers, an oxygen combustion fan, and a secondary heat exchange pipe network. The heat exchange flue is connected to the furnace chamber, and the flue gas after primary heat exchange enters the furnace chamber. The oxygen combustion fan is connected to the furnace chamber through an oxygen pipeline. Burners are installed in the furnace chamber for oxygen combustion of the flue gas. The secondary heat exchange pipe network is arranged within the furnace chamber for secondary heat exchange of the high-temperature flue gas after combustion. The secondary heat exchange pipe network is connected to the solid thermal storage module and forms a heat exchange medium circulation.

2. The heat recovery device for converter flue gas according to claim 1, characterized in that: A switching valve is installed between the heat exchange flue and the furnace.

3. The heat recovery device for converter flue gas according to claim 1, characterized in that: The solid thermal energy storage module includes a primary solid thermal energy storage module and a secondary solid thermal energy storage module. The primary solid thermal energy storage module is connected to the primary heat exchange network, and the secondary solid thermal energy storage module is connected to the secondary heat exchange network.

4. The heat recovery device for converter flue gas according to claim 1, characterized in that: The furnace is equipped with an upper air regulating plate and a lower air regulating plate. The burner is located below the upper air regulating plate, and the lower air regulating plate is located below the secondary heat exchange network to balance the flue gas in the furnace.

5. The heat recovery device for converter flue gas according to claim 1, characterized in that: The secondary heat exchange mechanism also includes an oxygen preheating chamber, through which the oxygen pipeline passes. When the flue gas flows through the oxygen preheating chamber, it preheats the oxygen in the oxygen pipeline.

6. The heat recovery device for converter flue gas according to claim 1, characterized in that: The exhaust gas emission system includes one or more of the following: desulfurization and denitrification equipment, steam boiler drum, dust removal equipment, and carbon dioxide capture equipment.

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