Blast furnace gas dehumidification system using blast furnace slag flushing water waste heat for refrigeration

Abstract

This utility model relates to the field of metallurgical ironmaking production and discloses a blast furnace gas dehumidification system utilizing the waste heat of blast furnace slag flushing water for cooling. The system includes a slag flushing water circulation network, a low-temperature lithium bromide chiller unit, a chilled water tank, a chilled water circulation pump, a blast furnace gas cooler, and a condensate collection tank. The chilled water tank, chilled water circulation pump, blast furnace gas cooler, and chilled water tank are sequentially connected to form a chilled water circulation pipeline. The heat source interface of the low-temperature lithium bromide chiller unit is connected to the slag flushing water circulation network, its chilled water inlet interface is connected to the outlet of the chilled water circulation pump, and its chilled water outlet is connected to the inlet of the blast furnace gas cooler. The blast furnace gas pipeline is connected to the inlet of the blast furnace gas cooler, and the outlet of the blast furnace gas cooler is connected to the condensate collection tank and subsequent blast furnace gas treatment processes via pipelines. This utility model realizes the use of the waste heat resources of blast furnace slag flushing water for cooling and dehumidifying blast furnace gas, improving energy utilization efficiency.

Description

Technical Field

[0001] This utility model relates to the field of metallurgical ironmaking production, and in particular to a blast furnace gas dehumidification system that utilizes the waste heat of blast furnace slag flushing water for cooling. Background Technology

[0002] In the metallurgical ironmaking process, the blast furnace is equipped with a slag flushing water system. This flushing water is used to remove the physical heat from the blast furnace slag. After absorbing heat, the temperature of the flushing water rises to 90℃ and needs to be cooled to below 60℃ before it can be recycled. Excessive water temperature not only affects the granulation effect of the blast furnace slag but also leads to the generation of large amounts of foamy slag, slag wool, and steam during flushing, adversely affecting slag transportation, slag sedimentation, and the normal operation of the slag filter. Furthermore, excessively high water temperature can cause pump cavitation, reducing pump output and shortening pump lifespan.

[0003] Currently, blast furnace slag flushing water is typically cooled using cooling towers to below 60°C for recycling. This process fails to utilize waste heat resources, resulting in energy waste and hindering sustainable development. Furthermore, with continuous advancements in steel production processes and the widespread application of technologies to increase blast furnace smelting intensity and reduce costs, the content of acidic gases (HCl, HF, HCN, SO2, etc.) in blast furnace gas is increasing, creating numerous challenges for subsequent blast furnace gas purification processes. Pre-treatment by cooling blast furnace gas is a relatively mature technology, but it consumes significant amounts of energy. Therefore, how to fully utilize the low-quality waste heat resources of blast furnace slag flushing water while simultaneously reducing energy consumption for blast furnace gas cooling has become a widespread concern among steel companies. Utility Model Content

[0004] This invention aims to solve the technical problems existing in the prior art. Therefore, this invention provides a blast furnace gas dehumidification system that utilizes the waste heat of blast furnace slag flushing water for cooling, thereby achieving waste heat recovery from the blast furnace slag flushing water and reducing the energy consumption for cooling blast furnace gas.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling is provided. The system includes a slag flushing water circulation network, a low-temperature lithium bromide chiller unit, a chilled water tank, a chilled water circulation pump, a blast furnace gas cooler, and a condensate collection tank. The chilled water tank, chilled water circulation pump, blast furnace gas cooler, and chilled water tank are sequentially connected to form a chilled water circulation network. The heat source interface of the low-temperature lithium bromide chiller unit is connected to the slag flushing water circulation network, its chilled water inlet interface is connected to the outlet of the chilled water circulation pump, and its chilled water outlet is connected to the inlet of the blast furnace gas cooler. The blast furnace gas network is connected to the inlet of the blast furnace gas cooler, and the outlet of the blast furnace gas cooler is connected via pipelines to the condensate collection tank and subsequent blast furnace gas treatment processes.

[0007] In some optional embodiments, the blast furnace gas cooler is further provided with a spray tower at the air inlet end, the air inlet of the spray tower being connected to the blast furnace gas pipeline network, and the air outlet being connected to the air inlet of the blast furnace gas cooler.

[0008] In some optional embodiments, the slag flushing water circulation network is a circulation network consisting of a slag flushing water tank and a slag flushing water circulation pump connected by pipes. The hot water inlet of the low-temperature lithium bromide chiller is connected to the outlet of the slag flushing water circulation pump, and its hot water outlet is connected to the inlet of the slag flushing water tank.

[0009] In some optional embodiments, a first electric butterfly valve is provided on the pipeline at the outlet of the slag flushing water circulation pump, and a bypass pipe is provided in parallel with the electric butterfly valve on the pipeline. A slag flushing water heating device is provided on the bypass pipe, and a second electric butterfly valve and a third electric butterfly valve are respectively provided at the inlet and outlet of the slag flushing water heating device.

[0010] In some optional embodiments, the slag flushing water heating device is a steam heat exchange heating device, which includes a plate heat exchanger installed on a bypass pipe. The heat source inlet of the plate heat exchanger is connected to a steam pipeline network, and the heat source outlet is connected to a condensate tank. The condensate tank is connected to a condensate pipeline network through a condensate pump.

[0011] In some alternative embodiments, the blast furnace gas cooler is equipped with a first thermometer and a flow meter at its water inlet and a second thermometer at its water outlet.

[0012] In some optional embodiments, the air inlet end of the spray tower is provided with a fourth electric butterfly valve and a first electric blind valve in sequence, and the air outlet end of the blast furnace gas cooler is provided with a second electric blind valve and a fifth electric butterfly valve in sequence.

[0013] In some optional embodiments, a bypass pipe is provided on the pipeline between the air inlet of the spray tower and the air outlet of the blast furnace gas cooler, and a sixth electric butterfly valve, a third electric blind plate valve and a seventh electric butterfly valve are sequentially provided on the bypass pipe.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] 1. This utility model utilizes a low-temperature lithium bromide refrigeration unit to absorb the low-quality waste heat of slag flushing water and generate chilled water. The chilled water cools the blast furnace gas through a blast furnace gas cooler, thereby realizing the use of the waste heat resources of blast furnace slag flushing water for the cooling and dehumidification treatment of blast furnace gas and improving energy utilization.

[0016] 2. A spray tower was added before the blast furnace gas cooler to dissolve acidic substances in the blast furnace gas in water, remove some dust, and reduce the gas temperature, thereby reducing the heat load on the subsequent blast furnace gas heat exchanger and ensuring stable system operation.

[0017] 3. A steam heat exchange heating device was added to the outlet pipeline of the slag flushing water circulation pump as a backup, which increased the reliability of the system and enabled the uninterrupted operation of the blast furnace gas dehumidification system.

[0018] 4. The bypass pipe is installed so that the production of blast furnace gas users is not affected when the blast furnace gas cooler is under maintenance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 This utility model provides a blast furnace gas dehumidification system that utilizes the waste heat from blast furnace slag flushing water for cooling.

[0021] The attached diagram lists the components represented by each number as follows:

[0022] 1—Slag flushing water tank, 2—Slag flushing water circulating pump, 3—Low-temperature lithium bromide refrigeration unit, 4—Chilled water tank, 5—Chilled water circulating pump, 6—Blast furnace gas cooler, 7—Condensate collection tank, 8—First thermometer, 9—Flow meter, 10—Second thermometer, 11—Spray tower, 12—First electric butterfly valve, 13—Bypass pipe, 14—Second electric butterfly valve, 15—Third electric butterfly valve, 16—Plate heat exchanger, 17—Condensate tank, 18—Condensate pump, 19—Fourth electric butterfly valve, 20—First electric blind valve, 21—Second electric blind valve, 22—Fifth electric butterfly valve, 23—Bypass pipe, 24—Sixth electric butterfly valve, 25—Third electric blind valve, 26—Seventh electric butterfly valve. Detailed Implementation

[0023] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] Furthermore, the terms "first," "second," etc., used in this utility model are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. The terms "installed," "connected," and "joined" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0028] Example 1

[0029] This embodiment provides a blast furnace gas dehumidification system utilizing the waste heat of blast furnace slag flushing water for cooling, including a slag flushing water circulation network, a low-temperature lithium bromide chiller unit 3, a chilled water tank 4, a chilled water circulation pump 5, a blast furnace gas cooler 6, and a condensate collection tank 7, wherein:

[0030] The slag flushing water circulation network is a circulation network consisting of slag flushing water tank 1 and slag flushing water circulation pump 2 connected by pipelines. The heat source interface of the low-temperature lithium bromide chiller 3 is connected to the slag flushing water circulation network. Specifically, the hot water inlet of the low-temperature lithium bromide chiller 3 is connected to the outlet of the slag flushing water circulation pump 2, and its hot water outlet is connected to the inlet of the slag flushing water tank 1. The generator in the low-temperature lithium bromide chiller 3 absorbs the heat energy in the slag flushing water.

[0031] The chilled water tank 4, chilled water circulation pump 5, blast furnace gas cooler 6, and chilled water tank 4 are sequentially connected to form a chilled water circulation pipeline. The chilled water inlet of the low-temperature lithium bromide refrigeration unit 3 is connected to the outlet of the chilled water circulation pump 5, and the chilled water outlet is connected to the inlet of the blast furnace gas cooler 6. The blast furnace gas pipeline is connected to the inlet of the blast furnace gas cooler 6, and the outlet of the blast furnace gas cooler 6 is connected to the condensate collection tank 7 and the subsequent blast furnace gas treatment process via pipelines. In the low-temperature lithium bromide refrigeration unit, the evaporator uses cooling water to cool down and outputs chilled water. The chilled water enters the blast furnace gas cooler to cool the blast furnace gas. After being cooled by the chilled water, the water vapor in the blast furnace gas condenses into liquid and is discharged into the condensate collection tank. The dehumidified blast furnace gas then enters the subsequent blast furnace gas treatment process for further processing.

[0032] Working principle: The slag flushing water in the slag flushing water pool is sent to the low-temperature lithium bromide refrigeration unit for heat exchange and to generate chilled water through the slag flushing water circulation pump. The chilled water enters the blast furnace gas cooler to exchange heat with the sprayed blast furnace gas. After heat exchange, the heated chilled water returns to the chilled water pool and is then circulated again by the chilled water circulation pump. After being cooled by the chilled water, the water vapor in the blast furnace gas condenses into liquid and is discharged into the condensate collection pool. The dehumidified blast furnace gas then enters the subsequent blast furnace gas treatment process for further processing.

[0033] Preferably, the blast furnace gas cooler 6 in this embodiment is equipped with a first thermometer 8 and a flow meter 9 at its water inlet and a second thermometer 10 at its water outlet, which can monitor the flow rate and temperature of the chilled water in real time.

[0034] This embodiment utilizes a low-temperature lithium bromide refrigeration unit to absorb the low-quality waste heat of the slag flushing water and simultaneously generate chilled water. The chilled water cools the blast furnace gas through a blast furnace gas cooler, thus realizing the use of the waste heat resources of the blast furnace slag flushing water for the cooling and dehumidification treatment of the blast furnace gas, thereby improving energy utilization efficiency.

[0035] Example 2

[0036] Based on Embodiment 1, this embodiment further includes a spray tower 11 at the inlet of the blast furnace gas cooler 6. The inlet of the spray tower 11 is connected to the blast furnace gas pipeline, and the outlet is connected to the inlet of the blast furnace gas cooler 6.

[0037] This embodiment can use a spray tower to remove acidic substances and some dust from blast furnace gas and reduce the temperature of the gas, thereby reducing the heat load on the subsequent blast furnace gas heat exchanger and ensuring stable system operation.

[0038] Example 3

[0039] Based on Embodiment 1 or Embodiment 2, this embodiment provides a first electric butterfly valve 12 on the pipeline at the outlet of the slag flushing water circulation pump 2, and a bypass pipe 13 is provided in parallel with the electric butterfly valve on the pipeline. A slag flushing water heating device is provided on the bypass pipe, and a second electric butterfly valve 14 and a third electric butterfly valve 15 are provided at the inlet and outlet of the slag flushing water heating device, respectively.

[0040] In one embodiment, the slag flushing water heating device is a steam heat exchange heating device, which includes a plate heat exchanger 16 installed on the bypass pipe 13. The heat source inlet of the plate heat exchanger 16 is connected to the steam pipeline network (a gate valve is provided at the heat source inlet end), and the heat source outlet is connected to the condensate tank 17. The condensate tank 17 is connected to the condensate pipeline network through the condensate pump 18.

[0041] This embodiment installs a slag flushing water heating device on the slag flushing water pipeline as a backup. When the blast furnace is not flushing slag, the slag flushing water is heated by the slag flushing water heating device, so as to achieve the purpose of uninterrupted operation of the blast furnace gas dehumidification system and increase the reliability of the system.

[0042] Example 4

[0043] Based on Embodiments 2 and 3, in this embodiment, a fourth electric butterfly valve 19 and a first electric blind valve 20 are sequentially provided at the air inlet end of the spray tower 11, and a second electric blind valve 21 and a fifth electric butterfly valve 22 are sequentially provided at the air outlet end of the blast furnace gas cooler 6.

[0044] A bypass pipe 23 is provided on the pipeline between the air inlet of the spray tower 11 and the air outlet of the blast furnace gas cooler 6. A sixth electric butterfly valve 24, a third electric blind valve 25 and a seventh electric butterfly valve 26 are sequentially provided on the bypass pipe 23.

[0045] This embodiment enables the supply of blast furnace gas to various users through a bypass pipe during blast furnace gas cooler maintenance, without affecting the continuity of production.

[0046] It is worth noting that the circulating pumps in the above embodiments are controlled by frequency converters, which improves the adjustability of the system.

[0047] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling, characterized in that: This includes a slag flushing water circulation network, a low-temperature lithium bromide refrigeration unit, a chilled water tank, chilled water circulation pumps, a blast furnace gas cooler, and a condensate collection tank, among which: The chilled water tank, chilled water circulation pump, blast furnace gas cooler, and chilled water tank are connected in sequence to form a chilled water circulation pipeline. The heat source interface of the low-temperature lithium bromide refrigeration unit is connected to the slag flushing water circulation network, its chilled water inlet interface is connected to the outlet of the chilled water circulation pump, and its chilled water outlet is connected to the inlet of the blast furnace gas cooler. The blast furnace gas pipeline is connected to the inlet of the blast furnace gas cooler, and the outlet of the blast furnace gas cooler is connected to the condensate collection tank and the subsequent blast furnace gas treatment process through pipelines.

2. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling according to claim 1, characterized in that: The blast furnace gas cooler is also equipped with a spray tower at its inlet. The inlet of the spray tower is connected to the blast furnace gas pipeline, and the outlet is connected to the inlet of the blast furnace gas cooler.

3. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling, as described in claim 1 or 2, is characterized in that: The slag flushing water circulation network is a circulation network consisting of a slag flushing water tank and a slag flushing water circulation pump connected by pipes. The hot water inlet of the low-temperature lithium bromide refrigeration unit is connected to the outlet of the slag flushing water circulation pump, and its hot water outlet is connected to the inlet of the slag flushing water tank.

4. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling according to claim 3, characterized in that: The pipe at the outlet of the slag flushing water circulation pump is equipped with a first electric butterfly valve, and a bypass pipe is connected in parallel with the electric butterfly valve on the same pipe. A slag flushing water heating device is installed on the bypass pipe, and a second electric butterfly valve and a third electric butterfly valve are respectively installed at the inlet and outlet of the slag flushing water heating device.

5. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling according to claim 4, characterized in that: The slag flushing water heating device is a steam heat exchange heating device, which includes a plate heat exchanger installed on a bypass pipe. The heat source inlet of the plate heat exchanger is connected to the steam pipeline network, and the heat source outlet is connected to the condensate tank. The condensate tank is connected to the condensate pipeline network through a condensate pump.

6. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling according to claim 1, characterized in that: The blast furnace gas cooler is equipped with a first thermometer and a flow meter at its water inlet and a second thermometer at its water outlet.

7. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling according to claim 2, characterized in that: The spray tower is equipped with a fourth electric butterfly valve and a first electric blind valve at its air inlet end, and the blast furnace gas cooler is equipped with a second electric blind valve and a fifth electric butterfly valve at its air outlet end.

8. The blast furnace gas dehumidification system utilizing waste heat from blast furnace slag flushing water for cooling according to claim 7, characterized in that: A bypass pipe is provided on the pipeline between the air inlet of the spray tower and the air outlet of the blast furnace gas cooler. A sixth electric butterfly valve, a third electric blind plate valve and a seventh electric butterfly valve are sequentially installed on the bypass pipe.

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