Waste heat recycling system

Abstract

According to the waste heat recycling system, flue gas waste heat is used as a high-temperature heat source of the lithium bromide unit, and energy waste is avoided. The waste heat recycling system comprises a heat exchange assembly and a lithium bromide unit, the heat exchange assembly is used for recycling coke oven flue gas, and the heat exchange assembly is communicated with the lithium bromide unit and can exchange heat with the lithium bromide unit so as to provide a heat source for the lithium bromide unit. On one hand, the waste heat of the flue gas can be recycled for the lithium bromide unit to use, the waste heat of the flue gas of the coke oven is effectively, deeply and comprehensively utilized, and energy is saved; on the other hand, the traditional mode that natural gas or steam is used for providing a high-temperature heat source needed by the lithium bromide unit is replaced, and waste of the natural gas or the steam is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat utilization, and in particular to a waste heat recovery and utilization system. Background Art

[0002] During the production process of the coke oven system, a large amount of flue gas is generated, and the temperature of the flue gas is above 300°C. This part of the flue gas needs to be deeply treated such as desulfurization, dust removal, and denitrification to meet the emission requirements; however, during the treatment process, there are requirements for the temperature required for each process, such as the flue gas inlet temperature of dust removal cannot exceed 250°C (≤250°), the flue gas outlet temperature of denitrification is not less than 230°C (≥230°), and the exhaust temperature cannot be lower than 160°C (≥160), etc. This causes the flue gas to have a large amount of waste heat during and after the deep treatment. At present, most of the waste heat in the coke oven flue gas cannot be effectively recycled and is directly discharged, resulting in energy waste. In view of this, how to utilize the waste heat in the flue gas has always been pursued by technical personnel in this field. Utility Model Content

[0003] The utility model provides a waste heat recovery and utilization system, which utilizes the waste heat of flue gas as a high-temperature heat source of a lithium bromide unit to avoid energy waste.

[0004] On the one hand, the waste heat recovery and utilization system of the utility model includes a heat exchange component and a lithium bromide unit. The heat exchange component is used to recover coke oven flue gas. The heat exchange component is connected to the lithium bromide unit and can exchange heat with the lithium bromide unit to provide a heat source for the lithium bromide unit.

[0005] In this way, on the one hand, the waste heat of the flue gas can be recovered and used for the lithium bromide unit, and the waste heat of the coke oven flue gas can be effectively and comprehensively utilized, saving energy; on the other hand, it replaces the traditional use of natural gas or steam to provide the high-temperature heat source required by the lithium bromide unit, avoiding the waste of natural gas or steam.

[0006] Optionally, the heat exchange component includes a first heat exchanger, and in the flow direction of the flue gas, the first heat exchanger is arranged upstream of the desulfurization, dust removal and denitrification system; and / or,

[0007] The heat exchange assembly comprises a second heat exchanger, and in the flow direction of the flue gas, the second heat exchanger is arranged downstream of the desulfurization, dust removal and denitrification system;

[0008] One of the first heat exchanger and the second heat exchanger is connected to the lithium bromide unit.

[0009] Optionally, both the first heat exchanger and the second heat exchanger are connected to the lithium bromide unit.

[0010] Optionally, the outlet end of the lithium bromide unit is respectively connected to the inlet end of the first heat exchanger and the inlet end of the second heat exchanger.

[0011] Optionally, a buffer device is further included, wherein the buffer device is connected between the first heat exchanger and the lithium bromide unit; and / or the buffer device is connected between the second heat exchanger and the lithium bromide unit.

[0012] Optionally, the lithium bromide unit includes a refrigeration unit and a heating unit, and the refrigeration unit and the heating unit are respectively connected in parallel with the heat exchange component.

[0013] Optionally, the lithium bromide unit includes a refrigeration unit and a heating unit, and the refrigeration unit, the heating unit and the heat exchange component are connected in series.

[0014] Optionally, the lithium bromide unit includes a refrigeration unit and a heating unit, the refrigeration unit includes a lithium bromide refrigerator and a cooling tower connected to the lithium bromide refrigerator, and the heating unit includes a lithium bromide heat pump.

[0015] Optionally, the heating unit further includes a hybrid machine and a water vapor compressor, and the lithium bromide heat pump, the hybrid machine and the water vapor compressor are connected in sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0017] Figure 1 It is a schematic diagram of a waste heat recovery system in an embodiment of the utility model.

[0018] Figure 1 middle:

[0019] 100. Waste heat recovery system; 101. Heat exchange component; 1011. First heat exchanger; 1012. Second heat exchanger; 102. Lithium bromide unit; 103. Buffer device; 200. Desulfurization, dust removal and denitrification system; 201. Desulfurization tower; 202. Dust removal device; 203. Denitrification device; 301. Fan. DETAILED DESCRIPTION

[0020] The utility model provides a waste heat recovery and utilization system, which utilizes the waste heat of flue gas as a high-temperature heat source of a lithium bromide unit to avoid energy waste.

[0021] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] The upstream and downstream in this article are based on the flow direction of the flue gas. In the technical solution of the present application, after the coke oven flue gas is discharged, it passes through the desulfurization tower 201 - dust removal device 202 - denitrification device - fan 301 in sequence and is then discharged. The upstream refers to the position closer to the coke oven side, and the downstream refers to the position closer to the flue gas being discharged into the atmosphere.

[0023] Relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0024] Please refer to Figure 1 , Figure 1 It is a schematic diagram of a waste heat recovery system in an embodiment of the utility model.

[0025] During the production process, the coke oven system generates a large amount of flue gas with a temperature of over 300°C. This part of the flue gas needs to be deeply treated by desulfurization, dust removal, denitrification and other treatments to meet the emission requirements. However, during the treatment process, there are temperature requirements for each process. For example, the flue gas inlet temperature for dust removal cannot exceed 250°C (≤250°), the flue gas outlet temperature for denitrification cannot be lower than 230°C (≥230°), and the exhaust temperature cannot be lower than 160°C (≥160), etc. This causes a large amount of waste heat in the flue gas during and after the deep treatment. At present, most of the waste heat in the coke oven flue gas cannot be effectively recycled and is directly discharged, resulting in energy waste.

[0026] The lithium bromide unit 102 can produce chilled water or high-grade heat source for use in subsequent operations. For example, chilled water is used for three-stage cooling of the coking primary cooler and raw coal gas cooling, and high-grade heat source can provide heating water and can also be used for ammonia distillation tower. However, the conventional lithium bromide unit 102 needs to use natural gas or steam as a drive, that is, the high-temperature heat source required by the lithium bromide unit 102 needs to be heated by natural gas or steam, and the natural gas or steam heating method causes energy waste.

[0027] Therefore, the conventional coke oven system and lithium bromide unit 102 have the following disadvantages:

[0028] First, the waste heat from coke oven flue gas cannot be effectively and deeply utilized, resulting in energy waste;

[0029] Second, the heat source of the lithium bromide unit 102 needs to be provided by natural gas or steam, and the energy consumption is high.

[0030] To this end, the present application provides a waste heat recovery system 100, such as Figure 1As shown, the waste heat recovery and utilization system 100 has the function of recovering the waste heat of the coke oven flue gas, and can also utilize the recovered waste heat; specifically, the waste heat recovery and utilization system 100 includes a heat exchange component 101 and a lithium bromide unit 102, the heat exchange component 101 can exchange heat with the coke oven flue gas to cool the flue gas, thereby recovering the waste heat of the coke oven flue gas, the heat exchange component 101 is connected to the lithium bromide unit 102, and exchanges heat with the working medium in the lithium bromide unit 102 to provide a heat source for the lithium bromide unit 102, thereby using the waste heat of the flue gas as a high-temperature heat source for the lithium bromide unit 102, and utilizing the recovered waste heat of the flue gas. This has two advantages. On the one hand, the waste heat of the flue gas can be recovered and used for the lithium bromide unit 102, and the waste heat of the coke oven flue gas is effectively and deeply utilized, saving energy; on the other hand, it replaces the traditional use of natural gas or steam to provide the high-temperature heat source required by the lithium bromide unit 102, avoiding the waste of natural gas or steam.

[0031] The above-mentioned heat exchange component 101 specifically includes a first heat exchanger 1011. In the flow direction of the flue gas, the first heat exchanger 1011 is arranged upstream of the desulfurization, dust removal and denitrification system 200. The first heat exchanger 1011 is arranged upstream of the desulfurization, dust removal and denitrification system 200, so that the waste heat of the flue gas can be collected before the flue gas enters the desulfurization, dust removal and denitrification system 200; and / or, the heat exchange component 101 includes a second heat exchanger 1012. In the flow direction of the flue gas, the second heat exchanger 1012 is arranged downstream of the desulfurization, dust removal and denitrification system 200. The second heat exchanger 1012 is arranged upstream of the desulfurization, dust removal and denitrification system 200. The method downstream of the desulfurization, dust removal and denitrification system 200 can collect the waste heat of the flue gas treated by the desulfurization, dust removal and denitrification system 200; when both the first heat exchanger 1011 and the second heat exchanger 1012 are set, the waste heat of the flue gas in different sections can be collected, thereby improving the collection efficiency of the flue gas waste heat; one of the first heat exchanger 1011 and the second heat exchanger 1012 is connected to the lithium bromide unit 102 to provide a heat source for the lithium bromide unit 102, or the first heat exchanger 1011 and the second heat exchanger 1012 are both connected to the lithium bromide unit 102 to provide a heat source for the lithium bromide unit 102.

[0032] The following is a specific example in which the first heat exchanger 1011 and the second heat exchanger 1012 are connected to the lithium bromide unit 102 to illustrate a specific solution.

[0033] As shown in the figure, the flue gas generated by the coke oven is about 300°C. The flue gas will pass through the first heat exchanger 1011, the desulfurization tower 201, the dust removal device 202, the denitrification device 203, the second heat exchanger 1012 and the fan 301 and other main equipment in sequence. In this process, after the heat exchange medium in the first heat exchanger 1011 and the second heat exchanger 1012 exchanges heat with the flue gas, the temperature will increase from the initial 110° to 130°. At this time, the first heat exchanger 1011 and the second heat exchanger 1012 The outlet of the heat exchange medium is connected to the inlet of the heat exchange medium of the lithium bromide unit 102, and heat exchange occurs in the lithium bromide unit 102 to form a high-temperature heat source of the lithium bromide unit 102. At the same time, the temperature of the heat exchange medium in the lithium bromide unit 102 is reduced to 110°, and then refluxes from the outlet of the heat exchange medium of the lithium bromide unit 102 to the inlet of the heat exchange medium of the first heat exchanger 1011 and the second heat exchanger 1012, and then recirculates to exchange heat with the flue gas to cool the flue gas.

[0034] In this embodiment, a water supply main and a return water main can be set up, and the outlets of the heat exchange medium of the first heat exchanger 1011 and the second heat exchanger 1012 (high-temperature heat exchange medium) are collected in the water supply main, and the inlet of the heat exchange medium of the lithium bromide unit 102 is connected to the water supply main, so that the high-temperature heat exchange medium can enter the lithium bromide unit 102 from the water supply main; the outlet of the heat exchange medium of the lithium bromide unit 102 (low-temperature heat exchange medium) is connected to the return water main, and the return water main diverts the low-temperature heat exchange medium to the inlet of the heat exchange medium of the first heat exchanger 1011 and the second heat exchanger 1012.

[0035] In another optional mode, a buffer device 103 is further provided, and the buffer device 103 is connected between the first heat exchanger 1011 and the lithium bromide unit 102; and / or, the buffer device 103 is connected between the second heat exchanger 1012 and the lithium bromide unit 102. The inlet and outlet of the heat exchange medium of the first heat exchanger 1011 and the second heat exchanger 1012 are both connected to the buffer device 103, and the buffer device 103 is, for example, a buffer water tank, and its main function is to prevent cavitation caused by air mixed in the pipeline when the circulating water pump is working.

[0036] The lithium bromide unit 102 of the present application includes a refrigeration unit and a heating unit, and the refrigeration unit or the heating unit is connected in series with the heat exchange component 101. The refrigeration unit includes a lithium bromide refrigerator and a cooling tower with the lithium bromide refrigerator; wherein, it can also be connected with a water vapor jet refrigeration device, an absorption ammonia refrigeration device, etc.; the heating unit includes a lithium bromide heat pump. The heating unit also includes a hybrid and a water vapor compressor, and the lithium bromide heat pump, the hybrid and the water vapor compressor are connected in sequence; wherein, other power generation equipment using waste heat, such as a turbine generator, etc., can also be connected; thereby, it is possible to use the waste heat of flue gas to provide a heat source for the refrigeration unit and the heating unit of the lithium bromide unit 102, and the refrigeration unit can form chilled water, which is used for the three-stage cooling of the coking primary cooler and for the cooling of the raw coal gas, etc. The heating unit can form a high-grade heat source, which can provide heating water and can also be used for the ammonia evaporation tower, etc.

[0037] The temperature and other parameters marked and cited in this embodiment are for reference only and are not intended to limit the specific temperature values ​​of the technical solution. The heat exchange medium of the first heat exchanger 1011 and the second heat exchanger 1012 can be water, steam, thermal oil and other auxiliary circulation media. The first heat exchanger 1011 and the second heat exchanger 1012 are not limited to plate heat exchangers and shell and tube heat exchangers, but also include various forms of waste heat boilers and other heat exchange equipment; in addition, in the embodiment of the present application, the waste heat recovery system 100 can also be arranged downstream of the fan 301 to further reduce the temperature of the flue gas discharged into the atmosphere. Those skilled in the art can make their own choices according to technical needs.

[0038] The above is a detailed introduction to the instrument supply device provided by the utility model. This article uses specific examples to illustrate the principle and implementation method of the utility model. The description of the above embodiments is only used to help understand the core idea of ​​the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. A waste heat recovery system, characterized in that: It comprises a heat exchange component and a lithium bromide unit. The heat exchange component is used to recover coke oven flue gas. The heat exchange component is connected with the lithium bromide unit and can exchange heat with the lithium bromide unit to provide a heat source for the lithium bromide unit.

2. The waste heat recovery system according to claim 1, characterized in that: The heat exchange assembly comprises a first heat exchanger, and in the flow direction of the flue gas, the first heat exchanger is arranged upstream of the desulfurization, dust removal and denitrification system; and / or, The heat exchange component includes a second heat exchanger. In the flow direction of the flue gas, the second heat exchanger is arranged downstream of the desulfurization, dust removal and denitrification system.

3. The waste heat recovery system according to claim 2, characterized in that: One of the first heat exchanger and the second heat exchanger is connected to the lithium bromide unit; or both of the first heat exchanger and the second heat exchanger are connected to the lithium bromide unit.

4. The waste heat recovery system according to claim 3, characterized in that: The outlet end of the lithium bromide unit is respectively connected to the inlet end of the first heat exchanger and the inlet end of the second heat exchanger.

5. The waste heat recovery system according to claim 2, characterized in that: It also includes a buffer device, which is connected between the first heat exchanger and the lithium bromide unit; and / or the buffer device is connected between the second heat exchanger and the lithium bromide unit.

6. The waste heat recovery system according to claim 1, characterized in that: The lithium bromide unit comprises a refrigeration unit and a heating unit, and the refrigeration unit and the heating unit are respectively connected in parallel with the heat exchange component.

7. The waste heat recovery system according to claim 1, characterized in that: The lithium bromide unit comprises a refrigeration unit and a heating unit, and the refrigeration unit, the heating unit and the heat exchange component are connected in series.

8. The waste heat recovery system according to any one of claims 1 to 7, characterized in that: The lithium bromide unit comprises a refrigeration unit and a heating unit. The refrigeration unit comprises a lithium bromide refrigerator and a cooling tower connected to the lithium bromide refrigerator. The heating unit comprises a lithium bromide heat pump.

9. The waste heat recovery system according to claim 8, characterized in that: The heating unit further includes a hybrid machine and a water vapor compressor, and the lithium bromide heat pump, the hybrid machine and the water vapor compressor are connected in sequence.

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