Gas-based shaft furnace top coal gas low-grade waste heat application system

Abstract

The utility model provides a kind of gas-based shaft furnace top coal gas low-grade waste heat application system, comprising: first heat exchange unit, for heat exchange between hot coal gas and cold heat exchange medium, output cold coal gas and hot heat exchange medium, the first heat exchange unit is connected with gas passage and heat exchange medium loop;Second heat exchange unit, series connection is arranged in the heat exchange medium loop, for heat exchange between hot heat exchange medium and to be heated raw material, output cold heat exchange medium and preheated raw material.The scheme realizes the recovery application of gas-based shaft furnace top coal gas low-grade waste heat.

Description

Technical Field

[0001] This utility model relates to the field of metallurgical technology, and in particular to a low-grade waste heat utilization system for top gas of a gas-based vertical furnace. Background Technology

[0002] As a crucial piece of equipment in low-carbon metallurgy, gas-based shaft furnaces typically discharge top gas at temperatures around 500-600℃, containing a significant amount of usable waste heat. This high-grade waste heat can be preheated using a heat exchanger to fully recover the high-temperature waste heat, reducing the temperature to around 200℃. However, there is currently no highly efficient method for recovering and utilizing the low-grade waste heat around 200℃. Common methods include heat pumps or ORC (Organic Rankine Cycle) power generation. However, these methods are inefficient, and the investment and maintenance costs of heat pumps and ORCs are high. Therefore, finding a way to efficiently recover low-grade waste heat with lower investment costs remains a challenge. Furthermore, the top gas from gas-based shaft furnaces contains a considerable amount of moisture, with H2O content reaching up to 20%. A large portion of the waste heat resides in the latent heat of vaporization of H2O; direct emission without recovery would result in energy waste. Utility Model Content

[0003] This utility model provides a system for utilizing the low-grade waste heat of top gas from a gas-based vertical furnace, so as to make use of the low-grade waste heat of top gas from the gas-based vertical furnace.

[0004] This utility model provides a low-grade waste heat utilization system for top gas of a gas-based vertical shaft furnace, the system comprising: The first heat exchange unit is used for heat exchange between hot coal gas and cold heat exchange medium, and outputs cold coal gas and hot heat exchange medium. The first heat exchange unit is connected to a coal gas passage and a heat exchange medium circuit. The second heat exchange unit is connected in series in the heat exchange medium circuit. It is used for heat exchange between the heat exchange medium and the raw material to be heated, and outputs the cold heat exchange medium and the preheated raw material.

[0005] In one embodiment of the present invention, the second heat exchange unit includes a raw material conveying channel and a heat exchange medium conveying channel. The raw material conveying channel includes a raw material inlet and a raw material outlet. The heat exchange medium conveying channel includes a gas inlet and a gas outlet. The raw material inlet and the gas outlet are arranged adjacent to each other, and the raw material outlet and the gas inlet are arranged adjacent to each other.

[0006] In one embodiment of this utility model, the heat exchange medium conveying channel is arranged from bottom to top in the direction from the gas inlet to the gas outlet.

[0007] In one embodiment of the present invention, the gas inlet is located below the raw material outlet, and the gas outlet is located above the raw material inlet.

[0008] In one embodiment of the present invention, a power device is connected in series in the heat exchange medium circuit, and the power device is used to provide power for the transportation of the heat exchange medium.

[0009] In one embodiment of this utility model, a switching valve group and a dust collector are connected in series in the heat exchange medium circuit. The switching valve group is used to control the on / off state of the heat exchange medium circuit, and the dust collector is used to remove dust from the cold heat exchange medium.

[0010] In one embodiment of the present invention, a dehydrator is connected in series in the heat exchange medium circuit, and the dehydrator is used to dehydrate the cold heat exchange medium.

[0011] In one embodiment of the present invention, the power device is connected in series at the input and output terminals of the second heat exchange unit.

[0012] In one embodiment of the present invention, an air inlet is provided in the heat exchange medium circuit. The air inlet is used to replenish the heat exchange medium and is located on the pipeline between the dehydrator and the first heat exchange unit.

[0013] In one embodiment of the present invention, the gas passage includes a hot gas inlet pipe and a cold gas outlet pipe, and a connecting pipe is provided between the hot gas inlet pipe and the cold gas outlet pipe, and a regulating valve is provided on the connecting pipe.

[0014] The beneficial effects of this utility model are as follows: This utility model proposes a low-grade waste heat utilization system for gas-based vertical shaft furnace top gas. By setting up a first heat exchange unit, heat exchange occurs between hot gas and a normal-temperature heat exchange medium, resulting in the output of cold gas and the hot heat exchange medium. This heats the cold heat exchange medium and enables the utilization of the low-grade waste heat from the gas-based vertical shaft furnace top gas. Then, through the setting up of a second heat exchange unit, heat exchange occurs between the hot heat exchange medium and the raw material to be heated, resulting in the output of a cold heat exchange medium and the preheated raw material, thus achieving the preheating of the raw material.

[0015] Throughout the process, the setup of the first and second heat exchange units ensures that the hot coal gas does not come into direct contact with the raw materials. This avoids both the reaction caused by the hot coal gas coming into contact with the raw materials and the contamination of the coal gas by the raw materials. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] In the attached diagram: Figure 1 This is a schematic diagram of the structure of a low-grade waste heat utilization system for top gas of a gas-based vertical furnace, provided in an embodiment of the present invention.

[0018] The attached figures are labeled as follows: First heat exchange unit 1, second heat exchange unit 2, raw material inlet 201, raw material outlet 202, gas inlet 203, gas outlet 204, cold gas outflow pipeline 3, hot gas inflow pipeline 4, butterfly valve 5, slide gate valve 6, connecting pipeline 7, regulating valve 8, power unit 9, dust collector 10, dehydrator 11, air supply port 12. Detailed Implementation

[0019] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0020] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0022] Please see Figure 1 As shown, an embodiment of this utility model provides a low-grade waste heat utilization system for gas-based vertical furnace top gas, comprising: The first heat exchange unit 1 is used for heat exchange between hot coal gas and cold heat exchange medium, and outputs cold coal gas and hot heat exchange medium. The first heat exchange unit 1 is connected to a coal gas passage and a heat exchange medium circuit. The second heat exchange unit 2 is connected in series in the heat exchange medium circuit. It is used for heat exchange between the heat exchange medium and the raw material to be heated, and outputs the cold heat exchange medium and the preheated raw material.

[0023] In this embodiment, a first heat exchange unit 1 is used to exchange heat between hot coal gas and a room-temperature cold heat exchange medium, outputting both cold coal gas and the heat exchange medium. This heat exchange medium is heated, and the low-grade waste heat of the top coal gas in the gas-based vertical shaft furnace is utilized. Then, a second heat exchange unit 2 is used to exchange heat between the heat exchange medium and the raw material to be heated, outputting both a cold heat exchange medium and the preheated raw material, thus preheating the raw material. Throughout the process, the arrangement of the first heat exchange unit 1 and the second heat exchange unit 2 prevents the hot coal gas from directly contacting the raw material. This avoids both a reaction between the hot coal gas and the raw material and contamination of the coal gas by the raw material.

[0024] For example, the heat exchange medium is an inert gas, such as nitrogen.

[0025] For example, the heat exchange medium is natural gas, and the raw material to be heated is ore pellets.

[0026] For example, the first heat exchange unit 1 is a heat exchanger, and the second heat exchange unit 2 is a belt preheating device.

[0027] In an exemplary embodiment, the second heat exchange unit 2 includes a raw material conveying channel and a heat exchange medium conveying channel. The raw material conveying channel includes a raw material inlet 201 and a raw material outlet 202. The heat exchange medium conveying channel includes a gas inlet 203 and a gas outlet 204. The raw material inlet 201 and the gas outlet 204 are arranged adjacent to each other, and the raw material outlet 202 and the gas inlet 203 are arranged adjacent to each other.

[0028] In this embodiment, the conveying direction of the raw material to be heated is opposite to the conveying direction of the heat exchange medium, thus achieving reverse heat exchange. During reverse heat exchange, the outlet temperature of the heated raw material will be closer to the temperature of the heat exchange medium. If heat exchange is carried out in the same direction, the temperature of the heated raw material will gradually decrease. Therefore, the heat exchange effect of reverse heat exchange is better than that of same-direction heat exchange, allowing the raw material to be heated more fully.

[0029] In one exemplary embodiment, the heat exchange medium transport channel is arranged from bottom to top in the direction from gas inlet 203 to gas outlet 204.

[0030] In this embodiment, the heat exchange medium is transported from bottom to top (i.e., diagonally).

[0031] In an exemplary embodiment, gas inlet 203 is located below raw material outlet 202, and gas outlet 204 is located above raw material inlet 201.

[0032] For example, the raw material is conveyed horizontally in the second heat exchange unit 2, and the heat exchange medium is conveyed from bottom to top in the second heat exchange unit 2. In order to realize the heat exchange medium being conveyed from bottom to top, the gas inlet 203 is located below the raw material outlet 202, and the gas outlet 204 is located above the raw material inlet 201.

[0033] In one exemplary embodiment, a power unit 9 is connected in series in the heat exchange medium circuit, and the power unit 9 is used to provide power for the transport of the heat exchange medium.

[0034] For example, the power unit 9 is a blower, which provides power for the transport of the heat exchange medium.

[0035] In an exemplary embodiment, a switching valve group and a dust collector 10 are connected in series in the heat exchange medium circuit. The switching valve group is used to control the on / off state of the heat exchange medium circuit, and the dust collector 10 is used to remove dust from the cold heat exchange medium.

[0036] It is worth noting that the switch valve assembly is designed to control the on / off state of the heat exchange medium circuit. Since the heat exchange medium and raw material will come into contact during heat exchange, leading to contamination of the heat exchange medium, a dust collector 10 is installed to reduce the amount of dust in the airflow.

[0037] In an exemplary embodiment, a dehydrator 11 is connected in series in the heat exchange medium circuit, and the dehydrator 11 is used to dehydrate the cold heat exchange medium.

[0038] It should be noted that, since the heat exchange medium carries some water during the heat exchange process with the raw material (such as water vapor condensation in the environment where the raw material is located), a dehydrator 11 is required for dehydration treatment.

[0039] In one exemplary embodiment, the input and output terminals of the second heat exchange unit 2 are respectively connected in series with a power unit 9.

[0040] For example, the heat exchange medium circuit includes a switching valve group, a power unit 9, a second heat exchange unit 2, a power unit 9, a switching valve group, a dust collector 10, and a dehydrator 11 connected in series.

[0041] The power unit 9 is provided at the input end of the second heat exchange unit 2 to transport the heat exchange medium to the second heat exchange unit 2, and the power unit 9 is provided at the output end of the second heat exchange unit 2 to transport the heat exchange medium to the dust collector 10.

[0042] In an exemplary embodiment, an air inlet 12 is provided in the heat exchange medium circuit. The air inlet 12 is used to replenish the heat exchange medium and is located on the pipeline between the dehydrator 11 and the first heat exchange unit 1.

[0043] It should be noted that during the heat exchange process between the heat exchange medium and the raw material, the heat exchange medium will come into direct contact with the raw material, and the environment in which the raw material is located cannot be guaranteed to be completely sealed, resulting in the loss of the heat exchange medium. Therefore, it is necessary to set up a heat exchange medium air inlet 12 to replenish the heat exchange medium.

[0044] In an exemplary embodiment, the gas passage includes a hot gas inlet pipe 4 and a cold gas outlet pipe 3, with a connecting pipe 7 between the hot gas inlet pipe 4 and the cold gas outlet pipe 3, and a regulating valve 8 is provided on the connecting pipe 7.

[0045] For example, a switch valve assembly is installed between the hot gas inlet pipe 4 and the pipe of the first heat exchange unit 1, and a switch valve assembly is installed between the cold gas outlet pipe 3 and the pipe of the first heat exchange unit 1. The switch valve assembly is installed to realize the on / off control of the corresponding pipes.

[0046] It should be noted that a connecting pipe 7 is provided between the hot gas inlet pipe 4 and the cold gas outlet pipe 3. A regulating valve 8 is connected to the connecting pipe 7. When the switch valve group between the hot gas inlet pipe 4, the cold gas outlet pipe 3 and the first heat exchange unit 1 is closed, the regulating valve 8 is opened to connect the hot gas inlet pipe 4 and the cold gas outlet pipe 3.

[0047] For example, the switching valve assembly includes a butterfly valve 5 and a gate valve 6, which are connected in series to increase the sealing performance when switching on and off and reduce the possibility of gas leakage.

[0048] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A system for utilizing low-grade waste heat from top gas of a gas-based vertical shaft furnace, characterized in that, include: The first heat exchange unit is used for heat exchange between hot coal gas and cold heat exchange medium, and outputs cold coal gas and hot heat exchange medium. The first heat exchange unit is connected to a coal gas passage and a heat exchange medium circuit. The second heat exchange unit is connected in series in the heat exchange medium circuit. It is used for heat exchange between the heat exchange medium and the raw material to be heated, and outputs the cold heat exchange medium and the preheated raw material.

2. The low-grade waste heat utilization system for gas-based vertical furnace top gas according to claim 1, characterized in that, The second heat exchange unit includes a raw material conveying channel and a heat exchange medium conveying channel. The raw material conveying channel includes a raw material inlet and a raw material outlet. The heat exchange medium conveying channel includes a gas inlet and a gas outlet. The raw material inlet and the gas outlet are arranged adjacent to each other, and the raw material outlet and the gas inlet are arranged adjacent to each other.

3. The low-grade waste heat utilization system for gas-based vertical furnace top gas according to claim 2, characterized in that, The heat exchange medium transport channel is arranged from bottom to top, from the gas inlet to the gas outlet.

4. The low-grade waste heat utilization system for gas-based vertical furnace top gas according to claim 2, characterized in that, The gas inlet is located below the raw material outlet, and the gas outlet is located above the raw material inlet.

5. The low-grade waste heat utilization system for gas-based vertical shaft furnace top gas according to any one of claims 1 to 4, characterized in that, A power unit is connected in series in the heat exchange medium circuit, and the power unit is used to provide power for the transportation of the heat exchange medium.

6. The low-grade waste heat utilization system for gas-based vertical shaft furnace top gas according to claim 5, characterized in that, A switching valve group and a dust collector are connected in series in the heat exchange medium circuit. The switching valve group is used to control the on and off of the heat exchange medium circuit, and the dust collector is used to remove dust from the cold heat exchange medium.

7. The low-grade waste heat utilization system for gas-based vertical furnace top gas according to claim 6, characterized in that, A dehydrator is connected in series in the heat exchange medium circuit, and the dehydrator is used to dehydrate the cold heat exchange medium.

8. The low-grade waste heat utilization system for gas-based vertical furnace top gas according to claim 5, characterized in that, The power unit is connected in series with the input and output terminals of the second heat exchange unit.

9. The low-grade waste heat utilization system for gas-based vertical furnace top gas according to claim 7, characterized in that, The heat exchange medium circuit is provided with an air inlet, which is used to replenish the heat exchange medium. The air inlet is located on the pipeline between the dehydrator and the first heat exchange unit.

10. The low-grade waste heat utilization system for gas-based vertical shaft furnace top gas according to claim 1, characterized in that, The gas passage includes a hot gas inlet pipe and a cold gas outlet pipe, and a connecting pipe is provided between the hot gas inlet pipe and the cold gas outlet pipe, and a regulating valve is provided on the connecting pipe.

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