Drum-type cold quenching treatment system for blast furnace slag

Abstract

The invention provides a blast furnace slag drum-type cold quenching treatment system which comprises a pretreatment unit connected with a slag outlet of a blast furnace and used for carrying out caching, temperature control and flow control treatment on slag; the dry type cold quenching treatment unit is connected with the pretreatment unit so as to receive the molten slag with the preset temperature and the preset flow, the dry type cold quenching treatment unit is provided with a slag groove and a roller arranged above the slag groove, a heat exchange cooling cavity is formed in the roller, and the roller is connected with a heat exchange circulation loop communicated with the heat exchange cooling cavity; a scraping device used for scraping high-temperature slag pieces is arranged on one side of the roller. And the post-treatment unit is connected with the dry-type cold quenching treatment unit to receive the high-temperature slag sheets, and the post-treatment unit is used for granulating and cooling the slag sheets. According to the invention, the problems of short service life of granulation equipment, high product quality control difficulty and low heat recovery efficiency in the existing blast furnace slag dry treatment technology can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel smelting, and particularly relates to a blast furnace molten slag roller type cold quenching treatment system. BACKGROUND

[0002] High-temperature liquid molten slag is a main byproduct of blast furnace smelting, and has extremely high solid waste resource recycling value and economic benefits. The discharge temperature of high-temperature liquid molten slag is as high as 1450 DEG C, and contains a large amount of high-temperature waste heat (about 60 kg of standard coal / t of molten slag).

[0003] At present, a mature technology for blast furnace molten slag treatment is water quenching and rapid cooling of blast furnace molten slag to form slag with high glass content, and the potential hydration activity makes it possible to be used as cement admixture and concrete admixture, and has a wide application in the field of building materials. However, this technology has problems such as small molten slag heat recovery rate (≤10%), large water resource waste, and environmental pollution, and with the increasing of energy saving and emission reduction tasks and the need of green and environmentally friendly ecological steel enterprises, it is urgent to use new technologies to realize efficient recovery of high-temperature liquid molten slag waste heat and resource utilization of products, and to solve the problems of environmental pollution and water resource waste.

[0004] Dry treatment of blast furnace molten slag has obvious potential advantages in reducing water resource consumption and molten slag preheating recovery, but due to the characteristics of high temperature, complex composition, large physical property change, discontinuous slag discharge, large slag flow fluctuation in the slag discharge process, and low thermal conductivity of blast furnace molten slag, the dry treatment technology of blast furnace molten slag still has problems such as short service life of granulation equipment, high product quality control difficulty, and low heat recovery efficiency, which need to be solved urgently.

[0005] Although the dry quenching process of blast furnace molten slag has been studied since the 1980s, there are mainly the following processes, but due to their respective reasons, they have not realized mature industrial application.

[0006] (1) Cooling rotary drum method:

[0007] The molten slag flows into the upper part of a pair of cooling rotary drums under the guidance of a slag channel, the rotary drums continuously rotate, and the organic coolant (alkyl biphenyl) with high boiling point absorbs the heat of the thin sheet in the rotary drum, the liquid molten slag contacts the surface of the rotary drum and generates a thin sheet (1000-1100 DEG C) thereon, the cooled slag is peeled off into a hopper by a scraper, and is further cooled to 250 DEG C by cold air, the organic coolant is discharged from the rotary drum outlet after absorbing heat, enters a heat exchanger and is cooled again, and then flows into the rotary drum again under the action of a pump for secondary recovery, and the recovered heat can be used for heating or steam power generation.

[0008] The above method can easily cause the roller to be blocked during production, and has low reliability; the instantaneous flow fluctuation of the slag and the uncertainty of the rotation of the drum make the thickness of the slag sheet unable to be accurately controlled, and the final slag product quality is unstable; the high-boiling-point and high-thermal-conductivity coolant is not easy to develop, which affects the quality of the slag product, the heat recovery efficiency is low, and the service life is low, so it has not been commercially promoted.

[0009] (2) Mechanical stirring method:

[0010] The molten slag continuously enters the stirring granulation device, is broken by the rotating force of the blades, and is cooled. The slag particles cooled by cooling are discharged under the pushing of the rotating force. The temperature of the discharged slag particles is about 900°C. In order to further recover and utilize the heat contained in the discharged slag particles, the heat contained in the discharged slag particles is further recovered and utilized. The slag particles obtained by the above method have a large diameter, most of which are 20 mm, and almost no glass body is contained in these slag particles. These slag particles are usually used as road paving materials.

[0011] This method causes slow cooling of the slag particles, cannot efficiently recover heat, and cannot produce high-value subsequent products, and does not have market promotion conditions.

[0012] (3) Air quenching method:

[0013] The molten slag discharged from the blast furnace is introduced into a special wind tunnel for granulation. The molten slag is micronized by high-speed airflow. The slag particles fall to the dispersion plate and the inner wall arranged in the wind tunnel. At this time, the temperature of the slag particles is reduced to about 1050°C. The slag particles are cooled by the air blown into the lower part of the wind tunnel during falling. The temperature of the slag particles when discharged from the wind tunnel is about 800°C. After the discharged slag particles are removed by the large-diameter particles through the vibrating screen, they are stored in the hot slag particle storage bin and are cooled to about 150°C through the multi-stage fluidized bed secondary heat exchange and are discharged.

[0014] The process has high air-slag ratio, high fan energy consumption, high operation cost, and may cause the recovered heat value to be lower than the input cost, and the designed device occupies a large area.

[0015] (4) Centrifugal granulation method:

[0016] The centrifugal granulation method uses the centrifugal force generated by the high-speed rotating cup / rotating disc / rotating drum to make the slag liquid spread to form a liquid film, further stretch and draw, and finally break to realize granulation. Then, the waste heat recovery system is used to recover and utilize the sensible heat of the solid small particles.

[0017] The above method has problems of slag crust, uneven granulated slag particle size and slag cotton, and needs to be further researched and improved. The granulating disc material is easily eroded by molten slag, and the uneven surface after the erosion will cause uneven distribution of molten slag on the disc surface, uneven liquid film thickness, and large particle size fluctuation of the granulated slag, even unable to granulate. The slag cotton is easily generated during rotation, which brings difficulties to the subsequent solid particle waste heat recovery. SUMMARY

[0018] The purpose of the present application is to provide a blast furnace molten slag drum-type cold quenching treatment system to solve the problems of short service life of granulating equipment, high product quality control difficulty and low heat recovery efficiency in the current blast furnace molten slag dry treatment technology.

[0019] The above technical purposes of the present application are mainly achieved by the following technical solutions.

[0020] The present application provides a blast furnace molten slag drum-type cold quenching treatment system, which comprises:

[0021] A pretreatment unit connected with the molten slag outlet of the blast furnace and used for buffering, temperature control and flow control of the molten slag;

[0022] A dry cold quenching treatment unit connected with the pretreatment unit to receive the molten slag with a predetermined temperature and a predetermined flow rate, the dry cold quenching treatment unit having a slag tank and a drum arranged above the slag tank, the drum forming a heat exchange cooling chamber inside and being connected with a heat exchange circulating loop in communication with the heat exchange cooling chamber, and one side of the drum being provided with a scraping device for scraping high-temperature slag pieces;

[0023] A post-treatment unit connected with the dry cold quenching treatment unit to receive the high-temperature slag pieces, the post-treatment unit being used for whole-grain and cooling treatment of the slag pieces.

[0024] In a preferred embodiment of the present application, the drum is installed on a lifting support, and the drum can move up and down under the drive of the lifting support to separate or contact the molten slag in the slag tank.

[0025] In a preferred embodiment of the present application, a steam generating device and a driving device are arranged on the heat exchange circulating loop, and the steam generating device is connected with a heat exchange water pipe.

[0026] In a preferred embodiment of the present application, the heat exchange working medium circulating in the heat exchange circulating loop is a liquid alloy.

[0027] In a preferred embodiment of the present application, the slag tank is configured to move left and right relative to the drum.

[0028] In a preferred embodiment of the present application, the dry quenching treatment unit further comprises a dust hood, which is arranged above the slag tank to cover the roller.

[0029] In a preferred embodiment of the present application, the dust hood is configured to move left and right relative to the slag tank.

[0030] In a preferred embodiment of the present application, the dust hood is provided with a heat preservation layer; and / or, the dust hood is provided with a liquid level detector for monitoring the liquid level of the molten slag in the slag tank; and / or, the dust hood is provided with a temperature detector for monitoring the temperature of the molten slag in the slag tank.

[0031] In a preferred embodiment of the present application, the pretreatment unit has a buffer tank, which is provided with an electric heating device, and the outlet of the buffer tank is provided with an outlet flow control device for controlling the flow rate of the molten slag flowing into the slag tank.

[0032] In a preferred embodiment of the present application, the post-treatment unit has a crushing device, a high-temperature conveying device, a high-temperature solid slag particle cooling device, and a low-temperature conveying device connected in sequence, and the high-temperature solid slag particle cooling device is connected with a cooling water pipe.

[0033] Compared with the prior art, the technical solution of the present application has the following characteristics and advantages:

[0034] The blast furnace slag roller type quenching treatment system of the present application can efficiently recover the heat of high-temperature liquid molten slag and produce high-value saturated steam, which can greatly reduce the water consumption per ton of slag compared with the existing water quenching process, avoids the emission of sulfides in the water quenching process, and produces high-value steam to bring considerable benefits to the enterprise. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor. In the drawings:

[0036] The drawings described herein are for purposes of illustration only and are not intended to limit the scope of the present disclosure in any way. Additionally, those skilled in the art will recognize that elements from the figures can be combined or modified to form still further implementations, which are also within the scope of the present disclosure.

[0037] Figure 1 The structure diagram of the blast furnace slag drum-type quenching treatment system described in the present application.

[0038] Legend of reference signs:

[0039] 100, pretreatment unit; 101, buffer tank; 102, electric heating device; 103, outlet flow control device;

[0040] 200, dry quenching treatment unit; 201, slag tank; 202, drum; 203, lifting support; 204, heat exchange circulation loop; 205, steam generating device; 206, driving device; 207, scraping device; 208, heat exchange water pipe; 209, dust hood; 210, dust hood support;

[0041] 300, post-treatment unit; 301, crushing device; 302, high-temperature conveying device; 303, high-temperature solid slag particle cooling device; 304, low-temperature conveying device; 305, cooling water pipe;

[0042] 400, blast furnace. DETAILED DESCRIPTION

[0043] In order to enable persons skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the scope of protection of the present application.

[0044] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present. The terms "vertical", "horizontal", "left", "right" and similar expressions as used herein are for purposes of explanation only and are not intended to limit the scope of the present application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] This invention provides a blast furnace slag drum-type cold quenching system, such as... Figure 1 As shown, it includes: a pretreatment unit 100, which is connected to the slag outlet of the blast furnace 400 and is used for buffering, temperature control, and flow control of the slag; a dry quenching unit 200, which is connected to the pretreatment unit 100 to receive slag with a predetermined temperature and a predetermined flow rate, the dry quenching unit 200 having a slag trough 201 and a drum 202 disposed above the slag trough 201, a heat exchange cooling chamber being formed inside the drum 202 and a heat exchange circulation loop 204 connected to the heat exchange cooling chamber, and a scraping device 207 for scraping high-temperature slag flakes being provided on one side of the drum 202; and a post-treatment unit 300, which is connected to the dry quenching unit 200 to receive high-temperature slag flakes, and the post-treatment unit 300 is used for granulation and cooling of the slag flakes.

[0047] The blast furnace slag drum-type cold quenching system of the present invention processes the blast furnace 400 molten slag through the buffering, temperature control and flow control of the pretreatment unit 100, transforming the unstable molten slag flow rate of the blast furnace 400 into a stable and controllable molten slag flow rate. Then, the molten slag is rapidly cooled into solid slag flakes through the dry cold quenching unit 200, and then granulated and cooled by the post-treatment unit 300 to produce dry slag particles with a high glass transition rate. This system can efficiently recover the heat of the high-temperature liquid molten slag and generate high-value saturated steam. Compared with the existing water quenching process, it can significantly reduce the water consumption per ton of slag and avoid the emission of sulfides in the water quenching process.

[0048] The following section will provide a detailed description of the specific structure of each part of the blast furnace slag drum-type cold quenching system described in this invention, as well as the position and connection relationship between each part.

[0049] like Figure 1 As shown, the blast furnace slag drum-type cold quenching system includes a pretreatment unit 100, a dry cold quenching unit 200, and a post-treatment unit 300 connected in sequence.

[0050] The pretreatment unit 100 is connected to the blast furnace 400. The high-temperature liquid slag produced by the blast furnace 400 enters the pretreatment unit 100. The pretreatment unit 100 is used to buffer, control the temperature and flow of the high-temperature liquid slag.

[0051] Specifically, such asFigure 1 As shown, the pretreatment unit 100 has a buffer tank 101, the inlet of which is connected to the slag outlet of the blast furnace 400 via a pipe. An electric heating device 102 is installed inside the buffer tank 101 to ensure the fluidity of the high-temperature liquid slag; the electric heating device 102 can be a resistance wire. An outlet flow control device 103 is installed at the outlet of the buffer tank 101 to control the flow rate of the high-temperature liquid slag towards the slag bin 201, thereby achieving flow control; the outlet flow control device 103 can be an electrically controlled valve or other flow control structure, which is not specifically limited here.

[0052] The pretreatment unit 100 receives the high-temperature liquid slag generated by the blast furnace 400 cycle. Through buffering, temperature control and flow control, the unstable slag flow rate of the blast furnace 400 is transformed into a stable and controllable slag flow rate, thereby ensuring the stability of the subsequent processing.

[0053] The dry quenching unit 200 is connected to the pretreatment unit 100. The high-temperature liquid slag with a predetermined temperature and flow rate flowing out of the pretreatment unit 100 enters the dry quenching unit 200. The dry quenching unit 200 rapidly cools the high-temperature liquid slag into solid slag through a dry drum quenching process.

[0054] Specifically, such as Figure 1 As shown, the dry quenching unit 200 has a slag tank 201 and a drum 202 positioned above the slag tank 201. The slag tank 201 receives the high-temperature liquid slag flowing out of the pretreatment unit 100 and provides conditions for the drum 202 to operate. The slag tank 201 is made of corrosion-resistant and heat-insulating material. The drum 202 is mounted on a lifting support 203 and can move up and down under the drive of the lifting support 203 to separate from or contact the slag in the slag tank 201. A heat exchange cooling chamber is formed inside the drum 202 and connected to a heat exchange circulation loop 204 that communicates with the heat exchange cooling chamber. The heat exchange circulation loop 204 is equipped with a steam generator 205 and a drive device 206 (liquid alloy circulation pump). The steam generator 205 is connected to a heat exchange water pipe 208. The heat exchange medium circulating in the heat exchange loop 204 is a liquid alloy. This liquid alloy has high thermal conductivity, enabling rapid cooling of the molten slag adhering to the outer wall of the drum 202 during rotation, thus forming slag flakes with a high glass transition rate. The drum 202 is used to rapidly cool the molten slag into solid slag. The side wall of the drum 202 is cooled by circulating liquid alloy, which rapidly cools the high-temperature liquid slag into solid slag during rotation and heats the low-temperature liquid alloy to a high temperature. A scraping device 207, which is a scraper that contacts the side wall of the drum 202, is provided on one side of the drum 202 to scrape off the high-temperature slag flakes.

[0055] Preferably, the slag trough 201 is movable for easy replacement; in this embodiment, the bottom of the slag trough 201 is provided with rollers.

[0056] The specific workflow of the dry quenching unit 200 is as follows:

[0057] After the high-temperature liquid slag in the slag tank 201 reaches the set height, the heat exchange circulation loop 204 is started, so that the liquid alloy circulates between the drum 202 and the steam generator 205. The drum 202 rotates under the drive of the end motor and descends through the lifting bracket 203. The lower part of the drum 202 is partially immersed in the high-temperature liquid slag. When the drum 202 rotates, it quickly cools the slag and sticks it to the surface of the drum 202 to form a relatively uniform solid slag sheet. The solid slag sheet is peeled off by the scraper on one side of the drum 202 and enters the next process. The cryogenic liquid alloy flows into the heat exchange and cooling chamber inside the drum 202 through one end. The heat from the high-temperature liquid slag is transferred to the cryogenic liquid alloy through the metal outer wall of the drum 202. After gaining heat, the temperature of the cryogenic liquid alloy rises. The heated high-temperature liquid alloy flows out from the other end of the drum 202. The high-temperature liquid alloy is heated by the steam generator 205 to generate high-pressure steam in the heat exchange water pipe 208. The cooled cryogenic liquid alloy returns to the drum 202 through the liquid alloy circulation pump to achieve cooling circulation.

[0058] The post-processing unit 300 is connected to the dry quenching unit 200. The high-temperature slag produced by the dry quenching unit 200 enters the post-processing unit 300, which is used to crush and cool the high-temperature slag.

[0059] Specifically, such as Figure 1 As shown, the post-processing unit 300 has a crushing device 301, a high-temperature conveying device 302, a high-temperature solid slag particle cooling device 303, and a low-temperature conveying device 304 connected in sequence. The high-temperature solid slag particle cooling device 303 is connected to a cooling water pipe 305. The crushing device 301 can be a double-roll crusher, the high-temperature conveying device 302 and the low-temperature conveying device 304 can both be belt conveyors, and the high-temperature solid slag particle cooling device 303 can be a solid-liquid heat exchanger.

[0060] High-temperature liquid slag is rapidly cooled by drum 202 to produce high-temperature solid slag flakes with a temperature of approximately 600°C. After being peeled off, the slag flakes enter crushing device 301 to be crushed into high-temperature slag particles with a particle diameter of approximately 5 mm. Driven by high-temperature conveying device 302, the high-temperature slag particles enter high-temperature solid slag particle cooling device 303. In the high-temperature solid slag particle cooling device 303, the high-temperature slag particles are cooled to a temperature convenient for transportation (e.g., below 100°C) by indirect cooling. At the same time, the low-temperature water in cooling water pipe 305 is heated into hot water or steam. The cooled low-temperature slag particles are transported to a designated site through low-temperature conveying device 304 and used as slag powder or roadbed aggregate.

[0061] According to one embodiment of the present application, as shown in Figure 1 The dry quenching treatment unit 200 further comprises a dust hood 209 covering the drum 202 above the slag tank 201.

[0062] Specifically, the top of the dust hood 209 is mounted on the dust hood support 210 by rollers, and the dust hood 209 can move left and right relative to the slag tank 201. The dust hood 209 is used to collect high-temperature flue dust above the slag tank 201; the heat preservation layer on the dust hood 209 has heat insulation function to reduce the heat loss of the molten slag in the slag tank 201.

[0063] The dust hood 209 has a liquid level detection function, and a liquid level detector is arranged above the dust hood 209 to feedback the liquid level of the molten slag in the slag tank 201 in real time, and is linked with the height of the drum 202, so that the immersion depth of the dry quenching drum 202 is stable and controllable, and the quality of the dry slag pieces quenched by the drum 202 is stable.

[0064] The dust hood 209 has a temperature detection function, and a temperature detector is arranged above the dust hood 209 to feedback the temperature of the molten slag in the slag tank 201 in real time, and is linked with the drum 202, so that the rotation speed of the drum 202, the flow of the liquid alloy, the temperature of the liquid alloy and other process parameters are adjusted according to the temperature, and the quality of the dry slag pieces quenched by the drum 202 is stable.

[0065] An observation window and an operating door are arranged on the dust hood 209, the state of the molten slag in the slag tank 201 is observed through the openable observation window, and the operating personnel handles the problems in the slag tank 201 through the openable operating door.

[0066] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only for specific embodiments of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A drum-type cold quenching system for blast furnace slag, characterized in that, include: A pretreatment unit (100) is connected to the slag outlet of the blast furnace (400) and is used to buffer, control the temperature and flow of the slag. A dry quenching unit (200) is connected to the pretreatment unit (100) to receive molten slag with a predetermined temperature and a predetermined flow rate. The dry quenching unit (200) has a slag tank (201) and a drum (202) disposed above the slag tank (201). A heat exchange cooling chamber is formed inside the drum (202) and a heat exchange circulation loop (204) connected to the heat exchange cooling chamber is provided. A scraping device (207) for scraping high-temperature slag flakes is provided on one side of the drum (202). A post-processing unit (300) is connected to the dry quenching unit (200) to receive the high-temperature slag flakes. The post-processing unit (300) is used to granulate and cool the slag flakes.

2. The blast furnace slag drum-type cold quenching system according to claim 1, characterized in that, The roller (202) is mounted on the lifting bracket (203). The roller (202) can move up and down under the drive of the lifting bracket (203) to separate from or contact the molten slag in the slag tank (201).

3. The blast furnace slag drum-type cold quenching system according to claim 1 or 2, characterized in that, The heat exchange circulation loop (204) is equipped with a steam generator (205) and a drive device (206), and the steam generator (205) is connected to a heat exchange water pipe (208).

4. The blast furnace slag drum-type cold quenching system according to claim 3, characterized in that, The heat exchange medium circulating in the heat exchange loop (204) is a liquid alloy.

5. The blast furnace slag drum-type cold quenching system according to claim 1 or 2, characterized in that, The slag trough (201) is configured to move left and right relative to the drum (202).

6. The blast furnace slag drum-type cold quenching system according to claim 1, characterized in that, The dry quenching unit (200) also includes a dust hood (209), which is positioned above the slag tank (201) to cover the roller (202).

7. The blast furnace slag drum-type cold quenching system according to claim 6, characterized in that, The dust hood (209) is configured to move left and right relative to the slag trough (201).

8. The blast furnace slag drum-type cold quenching system according to claim 6, characterized in that, The dust removal hood (209) is provided with a heat insulation layer; and / or, the dust removal hood (209) is provided with a liquid level detector for monitoring the liquid level of the molten slag in the slag tank (201); and / or, the dust removal hood (209) is provided with a temperature detector for monitoring the temperature of the molten slag in the slag tank (201).

9. The blast furnace slag drum-type cold quenching system according to claim 1, characterized in that, The pretreatment unit (100) has a buffer tank (101), an electric heating device (102) is provided in the buffer tank (101), and an outlet flow control device (103) is provided at the outlet of the buffer tank (101) to control the flow rate of the molten slag to the slag tank (201).

10. The blast furnace slag drum-type cold quenching system according to claim 1 or 9, characterized in that, The post-processing unit (300) has a crushing device (301), a high-temperature conveying device (302), a high-temperature solid slag particle cooling device (303) and a low-temperature conveying device (304) connected in sequence. The high-temperature solid slag particle cooling device (303) is connected to a cooling water pipe (305).

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