Blast furnace slag air quenching and air cooling waste heat recovery method and integrated waste heat recovery device

Abstract

The invention discloses a blast furnace slag air quenching and air cooling waste heat recovery method. A furnace body and a waste heat power generation boiler are included. The furnace body is divided into an upper section, a middle section and a lower section, high-speed jet air is introduced into the upper section of the furnace body, low-speed cooling air is introduced into the lower section of the furnace body, and the high-speed jet air and the low-speed cooling air are recycled by the middle section of the furnace body; comprising the following steps; pouring slag from the top of the furnace body; the slag is crushed into particles by high-speed jet air; the granular slag is cooled by low-speed cooling air in the process of falling and falling on the lower section of the furnace body; after the high-temperature high-speed jet flow air and the low-speed cooling air pass through the waste heat power generation boiler, new low-temperature high-speed jet flow air and low-speed cooling air are formed and enter the boiler body again. A circulating air path is constructed, an air inlet, on the furnace body, of the circulating air path is divided into two branches, one branch is connected to the upper section of the furnace body and used for crushing the slag into particles, and the other branch is arranged on the lower section of the furnace body and used for further cooling the particle-shaped slag; the circulating air path is connected to the furnace body middle section, hot air of the furnace body middle section is collected for power generation, and low-temperature air generated after power generation is conveyed into the furnace body through the air inlet. The purposes of improving the utilization efficiency of the waste heat of the molten slag and expanding the application range of the molten slag are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace slag waste heat recovery, and in particular to a blast furnace slag air quenching and air cooling waste heat recovery method and an integrated waste heat recovery device. Background Art

[0002] The temperature of blast furnace slag in the ironmaking industry is about 1400℃, and each ton of slag contains 1500MJ of sensible heat, which is about 51kg of quasi-standard coal. In order to effectively utilize this sensible heat, the blast furnace slag needs to be quickly cooled to a certain temperature in order to obtain slag with a certain content of amorphous glass, and at the same time, the heat needs to be effectively utilized.

[0003] At present, domestic blast furnace slag is quenched with water or cooled in a slag pit. By quickly cooling the blast furnace slag with a large amount of water, water slag with an amorphous glass content of more than 95% can be obtained. In this method, the temperature of the blast furnace slag will immediately drop to a temperature level below 100°C, and its heat cannot be effectively recovered. A large amount of water will also be consumed in this process, and a large amount of sulfides will be discharged. The obtained water slag needs to be dried before it can be used. When stored in the northern winter, it will inevitably produce ice or hardening, which increases the difficulty of handling. Cooling the blast furnace slag in the slag pit requires a considerable cooling time, and the resulting slag product cannot be used in the cement industry. The heat of the blast furnace slag will also be dissipated into the environment.

[0004] At present, foreign countries have studied the liquid slag air quenching technology in Japan, Germany, Sweden, South Korea and other countries. Among them, Japan's Nippon Steel, Kawasaki Steel, Sumitomo Metal and other companies have jointly conducted blast furnace slag air quenching granulation tests. The core device is the wind tunnel. The basic granulation process is that the molten slag is blown away by the high-speed air flow in the wind tunnel and granulated rapidly. The slag particles collide with the dispersion plate and the inner wall of the wind tunnel and fall down. After heat exchange with the cooling air below, they are discharged from the wind tunnel.

[0005] At present, the research on liquid slag gas quenching technology in China is mainly focused on steel slag gas quenching. The gas and waste heat recovery of liquid steel slag mainly refers to the liquid slag gas quenching technology, that is, the slag flows out of the slag ditch and is broken into particles under the action of high-speed air jets, and enters a heat exchanger under the transportation of air flow. The water-cooled walls around the heat exchanger and the moving bed at the bottom absorb the radiant heat of the high-temperature slag particles. At the same time, the air flow also takes away part of the heat of the particles to achieve the purpose of heat exchange. The slag treated by the above method can be used as cement raw material, but there are defects such as large equipment size, large air volume, low hot air temperature, and high energy consumption. The heat recovery rate is only 48%.

[0006] Summary of the Invention

[0007] In view of the above-mentioned defects in the prior art, a method for recovering waste heat from air quenching and cooling of blast furnace slag and an integrated waste heat recovery device are provided to improve the utilization efficiency of slag waste heat and expand the scope of use of slag.

[0008] The technical solution adopted by the present invention to solve the above technical problems is:

[0009] The method for recovering waste heat from air quenching and air cooling of furnace slag is characterized by comprising a furnace body and a waste heat power generation boiler; the furnace body is divided into three sections: upper, middle and lower; high-speed jet air is introduced into the upper furnace body, low-speed cooling air is introduced into the lower furnace body, and the high-speed jet air and low-speed cooling air are recovered from the middle furnace body; and the following steps are included;

[0010] Pour the slag into the furnace from the top;

[0011] The slag is broken into particles by high-speed jet wind;

[0012] The granular slag is cooled by low-speed cooling air as it falls and lands in the lower section of the furnace;

[0013] After the high-temperature high-speed jet wind and low-speed cooling wind pass through the waste heat power generation boiler, they form new low-temperature high-speed jet wind and low-speed cooling wind and re-enter the furnace body.

[0014] According to the above technical solution, the high-speed jet is blown vertically upward and is on the same vertical line as the direction in which the slag enters the furnace body and falls.

[0015] According to the above technical solution, a rotating cold slag discharging device is provided at the lower section of the furnace body. The speed at which the granular molten slag is discharged from the furnace body is controlled by adjusting the rotation speed of the rotating discharging device to control the residence time of the molten slag in the furnace body. If the temperature at the bottom of the furnace body drops rapidly, the rotation speed of the rotating discharging device is reduced; if the temperature at the bottom of the furnace body drops slowly, the rotation speed of the rotating discharging device is increased.

[0016] According to the above technical solution, after the high-temperature high-speed jet wind and low-speed cooling wind enter the waste heat power generation boiler, they need to exchange heat with the feed water preheater of the waste heat power generation boiler to further reduce the temperature of the new low-temperature high-speed jet wind and low-speed cooling wind.

[0017] According to the above technical solution, in the process that the high-temperature high-speed jet wind and the low-speed cooling wind pass through the waste heat power generation boiler to form new low-temperature high-speed jet wind and the low-speed cooling wind, the low-temperature high-speed jet wind and the low-speed cooling wind are filtered.

[0018] According to the above technical solution, the flow rate of the slag entering the furnace body is adjusted according to demand; the flow rate of the high-speed jet wind is controlled according to the flow rate of the slag entering the furnace body;

[0019] The new low-temperature high-speed jet wind accounts for 10% to 30% of the total air volume, and the new low-speed cooling air accounts for 70% to 90% of the total air volume.

[0020] The integrated waste heat recovery device comprises a vertically arranged furnace body, a cold slag recovery device located directly below the bottom of the furnace body, and a blast furnace slag storage tank for transferring slag to the furnace body. The furnace body is divided into three sections: upper, middle and lower. A blast furnace slag loading device is provided at the top of the furnace body, a rotary cold slag discharging device is provided at the lower section of the furnace body, and a spiral sealing valve is provided at the lower part of the rotary cold slag discharging device.

[0021] It also includes a high-speed jet air duct arranged in the upper section of the furnace body, a low-speed cooling air duct connected to the rotating cold slag discharging device, an annular return air duct connected to the middle section of the furnace body, a waste heat power generation boiler connected to the other end of the annular return air duct, a circulating fan connected to the other end of the waste heat power generation boiler, and a booster fan connected to the high-speed jet air duct. The circulating fan leads to two branches, one branch is connected to the booster fan, and the other branch is connected to the low-speed cooling air duct.

[0022] According to the above technical scheme, an annular partition is provided in the middle section of the furnace body, the top end of the annular partition is fixed on the inner wall of the middle section of the furnace body, an annular gap is formed between the middle part of the annular partition and the middle section of the furnace body, the annular gap is connected with the annular return air duct, and an inclined channel is formed between the bottom end of the annular partition and the inner wall of the furnace body, and the annular gap and the lower section of the furnace body are connected through the inclined channel.

[0023] According to the above technical scheme, a first-level inertial dust collector is provided in the area of ​​the annular return air duct close to the waste heat power generation boiler, and the first-level inertial dust collector adopts a vertical partition arranged in the duct; a second-level multi-tube cyclone dust collector is also provided between the waste heat power generation boiler and the circulating fan, and the second-level multi-tube cyclone dust collector adopts the existing structure.

[0024] According to the above technical scheme, it also includes a balanced breathing valve arranged at the end of the circulating fan outlet pipeline and a water supply pipeline connected to the waste heat power generation boiler. The balanced breathing valve adopts the existing structure; the water supply pipeline includes a feed water preheater, a deaerator, and a waste heat boiler feed water pump arranged on the water supply pipeline. The high-speed jet wind and low-speed cooling wind output by the circulating fan need to be passed into the feed water preheater and then into the low-speed cooling air duct and the booster fan.

[0025] The present invention has the following beneficial effects:

[0026] 1. Construct a circulating air path. The air inlet of the circulating air path on the furnace body is divided into two branches. One is connected to the upper part of the furnace body to crush the slag into granules, and the other is located in the lower part of the furnace body to further cool the granular slag. The circulating air path is connected to the middle part of the furnace body to collect the hot air in the middle part of the furnace body for power generation. The low-temperature air generated after power generation is transported into the furnace body through the air inlet.

[0027] First, the slag that has been broken by the high-speed jet wind can be cooled by the low-speed cooling wind in the subsequent process. Due to its small volume, it can speed up the heat exchange between the slag and the cooling wind, thereby speeding up the cooling speed of the slag. Moreover, compared with the existing technology, there is no waste of water resources, and the granulation effect of the blast furnace slag is good.

[0028] Secondly, the flow of granular slag can be more easily controlled through the rotating cold slag discharging device circulating air path, so as to easily control the residence time of slag in the furnace body, ensure the cooling time of blast furnace slag, and ensure high temperature and high pressure parameters of waste heat boiler.

[0029] Third, the use of circulating air can avoid heat dissipation.

[0030] In summary, the overall heat recovery rate can reach about 80%, and the low-temperature granular slag discharged into the cold slag recovery tank is transported to a cement plant or a building materials manufacturing plant for comprehensive use.

[0031] 2. In order to prevent a large amount of granular slag from entering the annular return air duct, an annular baffle is set in the furnace body. The annular baffle is used to change the path of high-temperature high-speed jet air and low-speed cooling air entering the annular return air duct, so as to avoid the path of the annular return air duct from overlapping with the falling path of the granular slag, thereby achieving the purpose of reducing the granular slag being directly sucked into the annular return air duct from the furnace body.

[0032] 3. In order to avoid the influence of granular slag entering the annular return air duct on the fan, a first-level inertial dust collector and a second-level multi-cyclone dust collector are installed.

[0033] 4. Use the circulating air to heat the water supply pipeline of the waste heat power generation boiler, further reduce the temperature of the circulating air, and improve the utilization rate of the slag waste heat.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. The specific implementation method of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0036] Figure 1 It is a structural schematic diagram of an embodiment provided by the present invention;

[0037] Figure 2 It is a schematic diagram of the principle of an embodiment provided by the present invention;

[0038] In the figure, 1, furnace body; 1-1, upper section; 1-2, middle section; 1-3, lower section; 2, cold slag recovery device; 3, blast furnace slag storage tank; 4, blast furnace slag loading device; 5, rotary cold slag discharging device; 6, spiral sealing valve; 7, high-speed jet air duct; 8, low-speed cooling air duct; 9, annular return air duct; 10, waste heat power generation boiler; 11, circulating fan; 12, booster fan; 13, annular partition; 14, first-stage inertial dust collector; 15, second-stage multi-tube cyclone dust collector; 16, balanced breathing valve; 17, water supply pipeline; 17-1, feed water preheater; 17-2, deaerator; 17-3, waste heat boiler feed water pump. DETAILED DESCRIPTION

[0039] The following is combined with Figure 1-2 The principles and features of the present invention are described, and the examples given are only used to explain the present invention and are not used to limit the scope of the present invention. In the following paragraphs, the present invention is described in more detail by way of example with reference to the accompanying drawings. According to the following description and claims, the advantages and features of the present invention will become clearer. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0040] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are intended only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0042] Reference Figure 1-2 As shown, the present invention provides an integrated waste heat recovery device.

[0043] Example 1

[0044] It includes a vertically arranged furnace body 1, a cold slag recovery device 2 located just below the bottom of the furnace body, and a blast furnace slag storage tank 3 for transferring slag to the furnace body. The furnace body is divided into an upper section 1-1, a middle section 1-2, and a lower section 1-3. The furnace body is a circular container lined with refractory materials. A blast furnace slag loading device 4 is provided on the top of the furnace body, a rotary cold slag discharging device 5 is provided at the lower section of the furnace body, and a spiral sealing valve 6 is provided at the lower part of the rotary cold slag discharging device.

[0045] It also includes a high-speed jet air duct 7 arranged in the upper section of the furnace body, a low-speed cooling air duct 8 connected to the rotating cold slag discharging device, an annular return air duct 9 connected to the middle section of the furnace body, a waste heat power generation boiler 10 connected to the other end of the annular return air duct, a circulating fan 11 connected to the other end of the waste heat power generation boiler, and a booster fan 12 connected to the high-speed jet air duct. The circulating fan leads to two branches, one branch is connected to the booster fan, and the other branch is connected to the low-speed cooling air duct.

[0046] In this embodiment, the blast furnace slag discharged from the blast furnace is collected into a blast furnace slag storage tank, and then the blast furnace slag storage tank is lifted to the top of the furnace body, and the blast furnace slag is poured into the blast furnace slag loading device, and the slag flow entering the furnace body is controlled by the blast furnace slag loading device; wherein, the blast furnace slag loading device adopts the existing structure.

[0047] The slag falls vertically from the bottom of the blast furnace slag loading device into the top of the high-speed jet air duct arranged in the center of the furnace body. The blast furnace slag is broken into particles by the high-speed jet air blown out of the high-speed jet air duct. The blast furnace slag broken into particles goes through a rising and falling process in the furnace body, passes through the middle section and the lower end of the furnace body in turn, and finally falls into the rotating cold slag discharging device located in the lower section of the furnace body. Low-speed cooling air is blown in from the low-speed cooling air duct connected to the rotating cold slag discharging device to further cool the granular slag located at the top of the rotating cold slag discharging device. After the slag is cooled to the preset temperature, it is discharged from the furnace body and enters the cold slag recovery device below the furnace body. The amount of slag discharged from the cold slag of the blast furnace slag is controlled by the spiral sealing valve at the bottom of the rotating cold slag recovery device.

[0048] In this process, after the blast furnace slag passes through the upper, middle and lower sections in the furnace body and stays for nearly 2 hours, the temperature of the blast furnace slag can be cooled from about 1400℃ to below 200℃. The high-speed jet air and low-speed cooling air delivered to the furnace body are heated to nearly 900℃ by the slag, and then collected by the annular return air duct located in the middle section and enter the waste heat power generation boiler to be converted into high-temperature and high-pressure superheated steam to generate electricity. The low-temperature granular slag discharged into the cold slag recovery tank is transported to the cement plant or building materials manufacturing plant for comprehensive use.

[0049] In addition, a circulating air path is formed, and the circulating air path is divided into two branches before entering the furnace body. One branch of the circulating air, about 20% (the ratio in this embodiment, which can also be adjusted to other ratios), is pressurized by the booster fan to become a high-speed jet wind, and is passed into the upper section of the furnace body through the high-speed jet wind duct; thereby, the blast furnace slag flowing into the top of the furnace body is broken into particles, and the granular slag first rises in the furnace body and then continues to fall to the lower section of the furnace body, and the high-speed jet wind enters the annular return air duct in the middle section of the furnace body. The other branch of the circulating air, about 80%, is directly transported to the rotating cold slag discharging device in the lower section of the furnace body by the low-speed cooling air duct; the low-speed cooling air passes through the granular slag and the rest of the lower section of the furnace body, and finally enters the annular return air duct in the middle section of the furnace body. After the above two branches are heated, they are collected to the waste heat power generation boiler through the annular return air duct in the middle section of the furnace body, and after being cooled by the waste heat power generation boiler, they are divided into two branches again and transported to the furnace body.

[0050] Based on the above measures, 1. The slag broken by high-speed jet wind can accelerate the heat exchange between the slag and the cooling wind in the subsequent cooling process by low-speed cooling wind due to its small volume, thereby accelerating the cooling speed of the slag. Moreover, compared with the existing technology, there is no waste of water resources, and the granulation effect of blast furnace slag is good.

[0051] 2. The flow of granular slag can be more easily controlled through the rotating cold slag discharging device circulating air path, so as to easily control the residence time of slag in the furnace body. The cooling time of blast furnace slag is guaranteed, the hot air temperature is high and the deviation is small, thus ensuring the high temperature and high pressure parameters of the waste heat boiler.

[0052] 3. The circulating air is used to avoid heat dissipation.

[0053] In summary, the overall heat recovery rate can reach about 80%.

[0054] Example 2

[0055] The structure and principle of Example 2 are similar to those of Example 1, except that an annular partition 13 is provided in the middle section of the furnace body, the top end of the annular partition is fixed on the inner wall of the middle section of the furnace body, an annular gap is formed between the middle part of the annular partition and the middle section of the furnace body, the annular gap is connected to the annular return air duct, and an inclined channel is formed between the bottom end of the annular partition and the inner wall of the furnace body, through which the annular gap and the lower section of the furnace body are connected.

[0056] In this embodiment, in order to prevent a large amount of granular slag from entering the annular return air duct, an annular baffle is provided in the furnace body. The annular baffle is utilized to change the path of the high-temperature, high-speed jet air and the low-speed cooling air entering the annular return air duct, thereby preventing the path of the annular return air duct from overlapping with the falling path of the granular slag, thereby achieving the purpose of reducing the granular slag directly being sucked into the annular return air duct from the furnace body.

[0057] Example 3

[0058] The structure and principle of Example 3 are similar to those of Examples 1 and 2, except that: in order to avoid the influence of granular slag entering the annular return air duct on the fan, a first-level inertial dust collector 14 is provided in the area of ​​the annular return air duct close to the waste heat power generation boiler, and the first-level inertial dust collector adopts a vertical partition arranged in the duct; a second-level multi-tube cyclone dust collector 15 is also provided between the waste heat power generation boiler and the circulating fan, and the second-level multi-tube cyclone dust collector adopts the existing structure.

[0059] The two-stage multi-cyclone dust collector can separate the dust carried by the circulating air to protect the circulating fan and booster fan arranged downstream.

[0060] Example 4

[0061] The structure and principle of Example 4 are similar to those of Examples 1-3, except that: it also includes a balanced breathing valve 16 arranged at the end of the circulating fan outlet pipeline, and a water supply pipeline 17 connected to the waste heat power generation boiler. The balanced breathing valve adopts the existing structure, and the function of the balanced breathing valve is to maintain the air volume of the circulating air; the water supply pipeline includes a feed water preheater 17-1, a deaerator 17-2, and a waste heat boiler feed water pump 17-3 arranged on the water supply pipeline. The high-speed jet wind and low-speed cooling wind output by the circulating fan need to be passed into the feed water preheater and then into the low-speed cooling air duct and the booster fan.

[0062] The water supply medium of the water supply pipeline is the low-temperature condensate of the generator set. After heat exchange, the condensate returns to the deaerator. After atmospheric thermal deoxidation, the condensate forms 104°C feed water. The waste heat boiler feed water pump pumps into the waste heat boiler. After the circulating air passes through the feed water preheater, it forms a circulating air of about 150°C.

[0063] In Examples 1-4, the waste heat power generation boiler is sequentially arranged with a superheater heating surface, an evaporator tube bundle heating surface, and an economizer tube bundle heating surface from the high-temperature hot air inlet to the outlet. The high-temperature and high-pressure steam from the waste heat boiler superheater enters the steam turbine generator unit to generate electricity, thereby completing the efficient waste heat utilization of high-temperature slag.

[0064] The present invention also provides a method for recovering waste heat from air quenching and air cooling of blast furnace slag.

[0065] It includes a furnace body and a waste heat power generation boiler; the furnace body is divided into three sections: upper, middle and lower. High-speed jet air is introduced into the upper furnace body, low-speed cooling air is introduced into the lower furnace body, and the high-speed jet air and low-speed cooling air are recovered by the middle furnace body;

[0066] Example 1

[0067] The method comprises the following steps:

[0068] S1: The blast furnace slag in the blast furnace slag storage tank is poured into the blast furnace slag loading device on the top of the furnace body, and the blast furnace slag flow rate is controlled by the slag loading device;

[0069] S2: The slag is poured into the furnace from the top through the slag loading device; in order to ensure that the high-speed jet wind breaks the slag thoroughly, the high-speed jet is blown vertically upward and on the same vertical line as the direction in which the slag enters the furnace body and falls.

[0070] S3: The molten slag is broken into particles by the high-speed jet wind; the blast furnace slag broken into particles of different sizes falls into the furnace body.

[0071] S4: The granular slag is cooled by low-speed cooling air during the process of falling and landing in the lower section of the furnace body.

[0072] In this process, the temperature of blast furnace slag can be cooled from about 1400℃ to below 200℃. The high-temperature hot air of nearly 900℃ collected in the annular return air duct in the middle section of the furnace body enters the waste heat boiler for heat exchange. The waste heat boiler produces superheated steam with high temperature and high pressure parameters for power generation. The cold slag of blast furnace slag is discharged from the rotating cold slag discharging device at the bottom of the integrated furnace to the cold slag recovery tank and then transported to the cement plant or building materials manufacturing plant for comprehensive use. The gas after heat exchange by the waste heat power generation boiler is pressurized by the circulating fan and the booster fan and then transported back to the furnace body.

[0073] In Example 1, a rotary cold slag discharge device is provided at the lower section of the furnace body. The speed of the granular molten slag discharged from the furnace body is controlled by adjusting the rotation speed of the rotary discharge device to control the time the molten slag stays in the furnace body. If the temperature at the bottom of the furnace body drops quickly, the rotation speed of the rotary discharge device is reduced; if the temperature at the bottom of the furnace body drops slowly, the rotation speed of the rotary discharge device is increased. In addition, the blast furnace slag flow rate is also controlled by the slag charging device.

[0074] In Example 1, after entering the waste heat power generation boiler, the high-temperature high-speed jet wind and low-speed cooling wind need to exchange heat with the feed water preheater of the waste heat power generation boiler to further reduce the temperature of the new low-temperature high-speed jet wind and low-speed cooling wind.

[0075] In Example 1, in order to protect the fan, the low-temperature high-speed jet wind and the low-speed cooling wind are filtered during the process in which the high-temperature high-speed jet wind and the low-speed cooling wind pass through the waste heat power generation boiler to form new low-temperature high-speed jet wind and the low-speed cooling wind.

[0076] In Example 1, the flow rate of the slag entering the furnace body is adjusted according to demand; the flow rate of the high-speed jet wind is controlled according to the flow rate of the slag entering the furnace body;

[0077] Preferably, the new low-temperature high-speed jet wind accounts for 10% to 30% of the total air volume, and the new low-speed cooling wind accounts for 70% to 90% of the total air volume.

[0078] Preferably, if a high-speed jet wind with a flow rate of 100m / s is used, the slag can be broken and blown into 3mm particles. The pressure head of the booster fan is about 180Kpa, and the flow rate is based on the empirical value of 200m 3 / t slag. The pressure head of the circulating fan is about 20Kpa, and the flow rate is based on the empirical value of 800m3 / t slag.

[0079] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A method for recovering waste heat from air quenching and air cooling of blast furnace slag, characterized in that: The method comprises a furnace body and a waste heat power generation boiler; the furnace body is divided into three sections: upper, middle and lower; high-speed jet air is introduced into the upper furnace body, low-speed cooling air is introduced into the lower furnace body, and the high-speed jet air and low-speed cooling air are recovered by the middle furnace body; the method comprises the following steps; Pour the slag into the furnace from the top; The slag is broken into particles by high-speed jet wind; The granular slag is cooled by low-speed cooling air as it falls and lands in the lower section of the furnace; After the high-temperature high-speed jet wind and low-speed cooling wind pass through the waste heat power generation boiler, they form new low-temperature high-speed jet wind and low-speed cooling wind and re-enter the furnace body.

2. The method for recovering waste heat from blast furnace slag quenching and cooling according to claim 1, characterized in that: The high-speed jet is blown vertically upward and is on the same vertical line as the direction in which the slag falls into the furnace body.

3. The method for recovering waste heat from blast furnace slag quenching and cooling according to claim 1, characterized in that: A rotating cold slag discharging device is arranged at the lower section of the furnace body. The speed of the granular molten slag being discharged from the furnace body is controlled by adjusting the rotation speed of the rotating discharging device, so as to control the residence time of the molten slag in the furnace body. If the temperature at the bottom of the furnace body drops faster, the rotation speed of the rotating discharging device is reduced; if the temperature at the bottom of the furnace body drops slower, the rotation speed of the rotating discharging device is increased.

4. The method for recovering waste heat from blast furnace slag quenching and cooling according to claim 1, characterized in that: After entering the waste heat power generation boiler, the high-temperature high-speed jet wind and low-speed cooling wind need to exchange heat with the feed water preheater of the waste heat power generation boiler to further reduce the temperature of the new low-temperature high-speed jet wind and low-speed cooling wind.

5. The method for recovering waste heat from blast furnace slag quenching and cooling according to claim 1, characterized in that: In the process that the high-temperature high-speed jet wind and the low-speed cooling wind pass through the waste heat power generation boiler to form new low-temperature high-speed jet wind and low-speed cooling wind, the low-temperature high-speed jet wind and the low-speed cooling wind are filtered.

6. The method for recovering waste heat from blast furnace slag quenching and cooling according to claim 1, characterized in that: The flow rate of slag entering the furnace body is adjusted according to demand; the flow rate of high-speed jet air is controlled according to the flow rate of slag entering the furnace body; The new low-temperature high-speed jet wind accounts for 10% to 30% of the total air volume, and the new low-speed cooling air accounts for 70% to 90% of the total air volume.

7. Integrated waste heat recovery device, characterized by: It includes a vertically arranged furnace body, a cold slag recovery device located just below the bottom of the furnace body, and a blast furnace slag storage tank for transferring slag to the furnace body. The furnace body is divided into three sections: upper, middle and lower. A blast furnace slag loading device is provided at the top of the furnace body, a rotary cold slag discharging device is provided at the lower section of the furnace body, and a spiral sealing valve is provided at the lower part of the rotary cold slag discharging device. It also includes a high-speed jet air duct arranged in the upper section of the furnace body, a low-speed cooling air duct connected to the rotating cold slag discharging device, an annular return air duct connected to the middle section of the furnace body, a waste heat power generation boiler connected to the other end of the annular return air duct, a circulating fan connected to the other end of the waste heat power generation boiler, and a booster fan connected to the high-speed jet air duct. The circulating fan leads to two branches, one branch is connected to the booster fan, and the other branch is connected to the low-speed cooling air duct.

8. The integrated waste heat recovery device according to claim 7, characterized in that: An annular partition is provided in the middle section of the furnace body, the top end of the annular partition is fixed on the inner wall of the middle section of the furnace body, an annular gap is formed between the middle part of the annular partition and the middle section of the furnace body, the annular gap is connected with the annular return air duct, and an inclined channel is formed between the bottom end of the annular partition and the inner wall of the furnace body, through which the annular gap and the lower section of the furnace body are connected.

9. The integrated waste heat recovery device according to claim 7, characterized in that: A primary inertial dust collector is provided in the area of ​​the annular return air duct close to the waste heat power generation boiler, and the primary inertial dust collector adopts a vertical partition arranged in the duct; a secondary multi-tube cyclone dust collector is also provided between the waste heat power generation boiler and the circulating fan, and the secondary multi-tube cyclone dust collector adopts an existing structure.

10. The integrated waste heat recovery device according to claim 7, characterized in that: It also includes a balanced breathing valve located at the end of the circulating fan outlet pipeline and a water supply pipeline connected to the waste heat power generation boiler. The balanced breathing valve adopts the existing structure; the water supply pipeline includes a feed water preheater, a deaerator, and a waste heat boiler feed water pump located on the water supply pipeline. The high-speed jet wind and low-speed cooling wind output by the circulating fan need to pass into the feed water preheater and then into the low-speed cooling air duct and the booster fan.

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