Multi-stage comprehensive utilization system for flue gas waste heat of electric furnace

Abstract

The utility model relates to a multi-stage comprehensive utilization system for flue gas waste heat of an electric furnace, which belongs to the technical field of flue gas waste heat recycling and comprises a settling chamber, a waste heat boiler and a flue gas heat exchanger which are sequentially arranged along the flow direction of flue gas, and the flue gas heat exchanger is connected with an ORC (organic Rankine cycle) unit to drive the ORC unit to generate power. The ORC unit is connected with a condensation heat exchanger so as to conduct heat exchange and condensation on the working medium after acting, and the condensation heat exchanger is connected with the smoke heat exchanger so as to achieve circulation of the working medium. A cooling medium inlet of the condensation heat exchanger is connected with a water supplementing tank, a cooling medium outlet of the condensation heat exchanger is connected with a deaerator, the deaerator is connected with a steam pocket, and the steam pocket is connected with the waste heat boiler. By means of multi-stage utilization of flue gas waste heat, waste heat recovery in a larger temperature range is achieved, economical efficiency is improved, and the flue gas waste heat recovery device is environmentally friendly and has wide market application prospects.

Description

Technical Field

[0001] The utility model belongs to the technical field of flue gas waste heat recovery and utilization, and relates to a multi-stage comprehensive utilization system of electric furnace flue gas waste heat. Background Art

[0002] In the current electric furnace smelting, the flue gas of the electric furnace is cooled by spraying or the sensible heat of the flue gas between 850℃ and 200℃ is recovered by the waste heat boiler, and then sent to the dust removal facility. The waste heat of the low-temperature flue gas below 200℃ is not utilized, resulting in the waste heat of the low-temperature flue gas below 200℃ being wasted. Utility Model Content

[0003] In view of this, the purpose of the utility model is to provide a multi-stage comprehensive utilization system of waste heat from electric furnace flue gas, so as to achieve waste heat recovery in a larger temperature range and improve the utilization rate of waste heat from electric furnace flue gas.

[0004] In order to achieve the above object, the utility model provides the following technical solutions:

[0005] A multi-stage comprehensive utilization system of waste heat from flue gas of an electric furnace comprises a settling chamber, a waste heat boiler and a flue gas heat exchanger which are sequentially arranged along the flow direction of the flue gas. The flue gas heat exchanger is connected to an ORC unit to drive the ORC unit to generate electricity. The ORC unit is connected to a condensing heat exchanger to perform heat exchange and condensation on a working medium after work. The condensing heat exchanger is connected to the flue gas heat exchanger to realize the circulation of the working medium. The cooling medium inlet of the condensing heat exchanger is connected to a water supply tank, the cooling medium outlet of the condensing heat exchanger is connected to a deaerator, the deaerator is connected to a steam drum, and the steam drum is connected to the waste heat boiler.

[0006] Optionally, a temperature monitoring device is provided on the flue gas outlet side of the flue gas heat exchanger, and a water make-up bypass regulating valve is provided on the pipeline connecting the water make-up tank and the condensing heat exchanger. The water make-up bypass regulating valve is interlocked with the temperature monitoring device to control the flue gas temperature on the flue gas outlet side.

[0007] Optionally, a water return bypass is provided on the pipeline connecting the deaerator and the condensing heat exchanger, and the water return bypass is connected to the water supply tank.

[0008] Optionally, a feed water pump is provided between the deaerator and the steam drum so as to pump water in the deaerator into the steam drum through the feed water pump.

[0009] Optionally, the steam drum is connected to a steam network.

[0010] Optionally, the flue gas enters the dust removal and purification system after passing through the flue gas heat exchanger.

[0011] The utility model has the following beneficial effects: through multi-stage utilization of flue gas waste heat, waste heat recovery in a larger temperature range is achieved, economic efficiency is improved, and it is environmentally friendly and has broad market application prospects.

[0012] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and research, or can be taught from the practice of the present invention to some extent. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be described in detail below in conjunction with the accompanying drawings, in which:

[0014] Figure 1 It is a schematic diagram of the utility model of the multi-stage comprehensive utilization system of electric furnace flue gas waste heat.

[0015] Reference numerals: settling chamber 1, waste heat boiler 2, flue gas heat exchanger 3, ORC unit 4, condensing heat exchanger 5, water supply tank 6, deaerator 7, steam drum 8. DETAILED DESCRIPTION

[0016] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0017] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present utility model. In order to better illustrate the embodiments of the present utility model, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0018] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the system or component referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0019] See also Figure 1 A multi-stage comprehensive utilization system of waste heat from flue gas of an electric furnace comprises a settling chamber 1, a waste heat boiler 2 and a flue gas heat exchanger 3 which are arranged in sequence along the flow direction of flue gas. The flue gas heat exchanger 3 is connected to an ORC unit 4 to drive the ORC unit 4 to generate electricity. The ORC unit 4 is connected to a condensing heat exchanger 5 to perform heat exchange and condensation on the working medium after work. The condensing heat exchanger 5 is connected to the flue gas heat exchanger 3 to realize the circulation of the working medium. The cooling medium inlet of the condensing heat exchanger 5 is connected to a water supply tank 6 to transport the cooling medium to the condensing heat exchanger 5. The cooling medium outlet of the condensing heat exchanger 5 is connected to a deaerator 7. The deaerator 7 is connected to a steam drum 8, and the steam drum 8 is connected to the waste heat boiler 2. The utility model uses the water with a higher temperature obtained after heat exchange by the condensing heat exchanger 5 for water use in the waste heat boiler 2, realizes the recycling of heat energy, and further improves the utilization rate of flue gas heat energy.

[0020] In order to improve the safety of the system, the utility model monitors and controls the flue gas outlet temperature of the flue gas heat exchanger 3 in real time, and the implementation means can be: a temperature monitoring device is set on the flue gas outlet side of the flue gas heat exchanger 3, and a water replenishment bypass regulating valve is set on the pipeline connecting the water replenishment tank 6 and the condensing heat exchanger 5. The water replenishment bypass regulating valve is interlocked with the temperature monitoring device to control the flue gas temperature on the flue gas outlet side. When the temperature on the flue gas outlet side is too high or too low, the water replenishment bypass regulating valve is used to adjust the water replenishment to achieve control of the working medium temperature, thereby controlling the heat exchange efficiency of the flue gas heat exchanger 3, and then controlling the flue gas temperature on the flue gas outlet side.

[0021] Optionally, a return water bypass is provided on the pipeline connecting the deaerator 7 and the condensing heat exchanger 5, and the return water bypass is connected to the water supply tank 6; a feed water pump is provided between the deaerator 7 and the steam drum 8 to pump the water in the deaerator 7 into the steam drum 8 through the feed water pump; the steam drum 8 is connected to the steam network; the flue gas enters the dust removal and purification system after passing through the flue gas heat exchanger 3.

[0022] The utility model recovers the waste heat of the electric furnace smoke while ensuring the safety of the system, can realize waste heat recovery in a larger temperature range, improves the efficiency of the steel plant, is environmentally friendly, and has broad market application prospects.

[0023] Example

[0024] A multi-stage comprehensive utilization system of waste heat from flue gas of electric furnace, such as Figure 1 As shown, it includes a settling chamber 1, a waste heat boiler 2, a flue gas heat exchanger 3, an ORC unit 4, a condensing heat exchanger 5, a water supply tank 6, a deaerator 7, a steam drum 8, and matching water pumps, valves, connecting pipes, and a control system. The settling chamber 1, the waste heat boiler 2, and the flue gas heat exchanger 3 are arranged in sequence along the flow direction of the flue gas; the flue gas of the electric furnace is first quickly cooled by the waste heat boiler 2, and then flows through the flue gas heat exchanger 3 to exchange heat with the working medium of the ORC unit 4; after absorbing heat, the working medium enters the ORC unit 4 to generate power and then enters the condensing heat exchanger 5; the water in the water supply tank 6 first flows into the condensing heat exchanger 5 to initially absorb heat, and then enters the deaerator 7 for deoxygenation, and at the same time, the excess water can return to the water supply tank 6 through the return water bypass; the working medium is condensed by the water supply in the condensing heat exchanger 5 and then returns to the flue gas heat exchanger 3 to absorb heat again for circulation; the water in the deaerator 7 is supplied to the steam drum 8 by the feed water pump, and after absorbing the waste heat of the flue gas of the electric furnace through heat exchange in the waste heat boiler 2, it is vaporized to generate steam for external use.

[0025] The working principle of the utility model is as follows:

[0026] It is divided into three processes:

[0027] S1 Flue gas process: Flue gas enters the settling chamber 1 from the electric furnace, and then passes through the waste heat boiler 2 for rapid cooling, and is sent to the flue gas heat exchanger 3 through the pipeline. After the heat is absorbed, it enters the dust removal pipeline and is transported to the dust removal facility. The flue gas outlet temperature of the flue gas heat exchanger 3 is monitored in real time, and the temperature is adjusted through the water supply bypass regulating valve when the temperature is too high or too low.

[0028] S2 Water circulation process: At the beginning, water enters the system from the inlet of the water supply tank 6. The water medium first flows from the water supply tank 6 into the condensing heat exchanger 5 for preliminary heat absorption, and then enters the deaerator 7 for deoxidation. At the same time, the excess water can be returned to the water supply tank 6 through the bypass 2. The water in the deaerator 7 is supplied to the steam drum 8 by the feed water pump. The water in the steam drum 8 circulates in the waste heat boiler 2 for heat exchange and absorbs part of the waste heat of the electric furnace flue gas, and vaporizes to generate steam for external use.

[0029] S3 working medium circulation process: At the beginning, the working medium enters the closed circulation system from the working medium inlet to maintain a certain pressure in the system. During smelting, the working medium is heated in the flue gas heat exchanger 3, and then enters the ORC unit 4 to generate power. After exhausting steam, it enters the condensing heat exchanger 5 for heat exchange and condensation, and finally returns to the flue gas heat exchanger 3. During the smelting cycle, the system circulates back and forth, continuously generating power.

[0030] Among them, there is heat exchange between the S2 and S3 processes at the condensing heat exchanger 3.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A multi-stage comprehensive utilization system of waste heat from flue gas from electric furnaces, characterized in that: The invention comprises a settling chamber (1), a waste heat boiler (2), and a flue gas heat exchanger (3) which are arranged in sequence along the direction of flue gas flow; the flue gas heat exchanger (3) is connected to an ORC unit (4) to drive the ORC unit (4) to generate electricity; the ORC unit (4) is connected to a condensing heat exchanger (5) to perform heat exchange and condensation on a working medium after work; the condensing heat exchanger (5) is connected to the flue gas heat exchanger (3) to realize the circulation of the working medium; the cooling medium inlet of the condensing heat exchanger (5) is connected to a water supply tank (6); the cooling medium outlet of the condensing heat exchanger (5) is connected to a deaerator (7); the deaerator (7) is connected to a steam drum (8); and the steam drum (8) is connected to the waste heat boiler (2).

2. The electric furnace flue gas waste heat multi-stage comprehensive utilization system according to claim 1 is characterized in that: A temperature monitoring device is provided on the flue gas outlet side of the flue gas heat exchanger (3), and a water supply bypass regulating valve is provided on the pipeline connecting the water supply tank (6) and the condensing heat exchanger (5). The water supply bypass regulating valve is interlocked with the temperature monitoring device to control the flue gas temperature on the flue gas outlet side.

3. The electric furnace flue gas waste heat multi-stage comprehensive utilization system according to claim 1 is characterized in that: A water return bypass is provided on the pipeline connecting the deaerator (7) and the condensing heat exchanger (5), and the water return bypass is connected to the water supply tank (6).

4. The electric furnace flue gas waste heat multi-stage comprehensive utilization system according to claim 1 is characterized in that: A feed water pump is provided between the deaerator (7) and the steam drum (8) so as to pump water in the deaerator (7) into the steam drum (8) through the feed water pump.

5. The electric furnace flue gas waste heat multi-stage comprehensive utilization system according to claim 1 is characterized in that: The steam drum (8) is connected to the steam network.

6. The electric furnace flue gas waste heat multi-stage comprehensive utilization system according to claim 1 is characterized in that: The flue gas passes through the flue gas heat exchanger (3) and then enters the dust removal and purification system.

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