Equipment for maintaining steel slag product by using low-temperature flue gas

Abstract

The utility model relates to the technical field of steel slag maintenance, in particular to equipment for maintaining a steel slag product by using low-temperature flue gas, which comprises a carbonization kettle for placing the steel slag product, low-temperature carbon dioxide flue gas is introduced into the carbonization kettle, and a water treatment device positioned below the steel slag product is arranged at the bottom in the carbonization kettle. A steam outlet pipeline with an outlet positioned below the steel slag product is arranged on the water treatment device; the low-temperature carbon dioxide flue gas comprises low-temperature carbon dioxide flue gas which is introduced into the upper part of the steel slag product from the upper end of the carbonization kettle through a first low-temperature carbon dioxide flue gas pipeline and low-temperature carbon dioxide flue gas which is introduced into the water treatment device below the steel slag product from the lower side part of the carbonization kettle through a second low-temperature carbon dioxide flue gas pipeline. According to the equipment for curing the steel slag products by using the low-temperature flue gas, low-temperature waste heat resources are better utilized, and meanwhile, the defect that the volume stability of part of the steel slag products is not thoroughly eliminated by carbonization curing is overcome.

Description

Technical Field

[0001] The utility model relates to the technical field of steel slag curing, in particular to a device for curing steel slag products by utilizing low-temperature flue gas. Background Art

[0002] Industries such as steel, cement, and thermal power generation are significant sources of high carbon emissions due to their extensive use of fossil fuels in their production processes. The effective utilization of waste heat from CO2 flue gases is crucial for reducing greenhouse gas emissions and promoting sustainable development. Waste heat resources can be categorized into three levels: high-temperature, medium-temperature, and low-temperature. High-temperature flue gas is exhaust gas with temperatures exceeding 500°C, medium-temperature flue gas ranges from approximately 200°C to 500°C, and low-temperature exhaust gas typically remains below 200°C, sometimes even approaching ambient temperature. High-temperature and medium-temperature waste heat resources have relatively high utilization rates due to their higher energy levels and ease of recovery. However, low-temperature waste heat resources have long been underutilized due to their lower energy quality, difficulty in recovery, and long recovery cycles, resulting in significant resource waste. Therefore, developing effective low-temperature waste heat recovery technologies and methods can not only improve energy efficiency but also promote sustainable business development and contribute to environmental protection.

[0003] Steel slag is a by-product emitted during the steelmaking process. It is characterized by rich free calcium and magnesium oxides, low cementitious properties, and high heavy metal content. The direct use of untreated steel slag poses a great risk to the mechanical properties and durability of steel slag-containing composites, but CO2 mineralization technology is beneficial for improving the inferior properties of steel slag. During the CO2 mineralization of steel slag, carbon dioxide can react with f-CaO and f-MgO, C2S, and Ca(OH)2 in the steel slag in a short period of time and convert them into carbonates, achieving permanent solidification. Therefore, using carbon dioxide from industrial exhaust gas for mineralization and curing of steel slag products (such as hollow bricks, solid bricks, mold shells, aerated blocks, etc.) is an effective resource recovery and carbon emission reduction strategy.

[0004] Currently, there are few studies on the resource utilization of low-temperature carbon dioxide flue gas waste heat, and most of them are limited to tail gas between 100-200℃, which is usually only used in the carbonization curing stage of steel slag. There are few reports on the utilization of flue gas below 100℃. Given that the flue gas required for carbonization curing of carbonized building materials needs to have a carbon dioxide content of more than 10% and a temperature of 50-150℃, a comprehensive utilization design can be specifically designed for low-temperature waste heat of tail gas (<200℃): ① Waste heat below 100℃ can be used in the sample pretreatment stage and carbonization stage to dry the specimens to remove excess moisture and achieve carbonization; ② For tail gas between 100-200℃, on the one hand, it can be passed into the carbonization kettle to directly carbonize the product, and on the other hand, it can be passed into the heat exchange device to generate hot water and steam for mineralization and then steam curing, completely eliminating f-CaO and f-MgO inside the steel slag product, and solving the problem of poor volume stability of steel slag. Utility Model Content

[0005] The technical problem addressed by this utility model is to overcome the shortcomings of the prior art by providing a device for curing steel slag products using low-temperature flue gas. This device utilizes the waste heat of low-temperature industrial flue gas (less than 200°C) as both a heat source and a carbon source, utilizing the waste heat of flue gas at different temperatures. This device can dry, carbonize, and steam-cure steel slag products immediately after demolding, consolidating the f-CaO and f-MgO within the slag and eliminating factors that contribute to poor slag volume stability.

[0006] The technical solution adopted by the utility model to solve the technical problem is: a device for curing steel slag products using low-temperature flue gas, comprising a carbonizing kettle for placing steel slag products,

[0007] Low-temperature carbon dioxide flue gas is introduced into the carbonizing kettle. A water treatment device is provided at the bottom of the carbonizing kettle, which is located below the steel slag product. The water treatment device is provided with a steam outlet pipe with an outlet located below the steel slag product. A certain amount of tap water is stored in the water treatment device. When the carbon dioxide flue gas at 100-200°C is introduced into the water, heat enters the water due to heat transfer, generating a large amount of steam, which enters the chamber through three steam outlet pipes 10 to achieve steam curing.

[0008] The low-temperature carbon dioxide flue gas includes the low-temperature carbon dioxide flue gas introduced from the upper end of the carbonization kettle into the upper part of the steel slag product through the first low-temperature carbon dioxide flue gas pipeline and the low-temperature carbon dioxide flue gas introduced from the lower side of the carbonization kettle into the water treatment device below the steel slag product through the second low-temperature carbon dioxide flue gas pipeline.

[0009] The first low-temperature carbon dioxide flue gas pipeline and the second low-temperature carbon dioxide flue gas pipeline are formed by dividing the low-temperature carbon dioxide flue gas main pipeline.

[0010] The first low-temperature carbon dioxide flue gas pipeline and the second low-carbon dioxide flue gas pipeline are both provided with low-carbon dioxide flue gas inlet valves.

[0011] Furthermore, a temperature detector is provided on the low-temperature carbon dioxide flue gas main pipeline for detecting the waste heat temperature at the air inlet end.

[0012] The temperature detector is used to classify the low-temperature carbon dioxide flue gas introduced. The flue gas below 100°C is directly introduced into the carbonization kettle through the first low-temperature carbon dioxide flue gas pipeline to dry and carbonize the steel slag products. The tail gas at 100-200°C can be directly introduced into the carbonization kettle through the first low-temperature carbon dioxide flue gas pipeline or introduced into the water treatment device through the second low-temperature carbon dioxide flue gas pipeline to generate water vapor for steam curing of the steel slag products, thereby obtaining steel slag products with good volume stability.

[0013] Furthermore, the upper end of the carbonization kettle is connected to a reactor vent pipe with a reactor vent valve; the lower side of the carbonization kettle is connected to a vacuum pump through a pipeline with a reactor exhaust valve to form a vacuum pumping device to accelerate the entry of carbon dioxide flue gas into the carbonization kettle.

[0014] Furthermore, the water treatment device is connected to a water inlet pipe extending to the outside of the carbonization kettle, and the water inlet pipe is provided with a water inlet valve located outside the carbonization kettle.

[0015] Furthermore, the carbonization kettle is provided with a carbon dioxide concentration detector and a pressure gauge for checking the concentration and pressure changes in the carbonization kettle during the reaction.

[0016] Furthermore, the carbonizing kettle is provided with several layers of stainless steel racks for placing steel slag products.

[0017] Specifically, the temperature detector has a temperature measurement range of -20 to 350°C with a resolution of 0.1°C. The carbonization kettle is made of 316L stainless steel and can withstand a pressure of 3MPa. The carbon dioxide concentration detector has a measurement range of 0 to 99% Vol and a resolution of 0.01% Vol. The pressure gauge has a measurement range of -0.1 to 10 MPa and an accuracy level of 0.4. The vacuum pump is a rotary vane vacuum pump that can evacuate to -0.9 bar.

[0018] The beneficial effects of the utility model are as follows: the equipment of the utility model utilizes low-temperature flue gas to cure steel slag products, utilizes a temperature detector to classify the introduced low-temperature carbon dioxide flue gas, and directly introduces the flue gas below 100°C into the carbonization kettle through the first low-temperature carbon dioxide flue gas pipeline to dry and carbonize the steel slag products; the tail gas at 100-200°C can be directly introduced into the carbonization kettle through the first low-temperature carbon dioxide flue gas pipeline or introduced into the water treatment device through the second low-temperature carbon dioxide flue gas pipeline to generate water vapor to steam-cure the steel slag products, thereby obtaining steel slag products with good volume stability.

[0019] It makes better use of low-temperature waste heat resources and overcomes the defect that carbonization curing does not completely eliminate the volume stability of some steel slag products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a structural diagram of the present utility model.

[0022] Numbers in the figure: 1-temperature detector, 2-low-temperature carbon dioxide flue gas main pipeline, 3-first low-temperature carbon dioxide flue gas pipeline, 4-second low-carbon dioxide flue gas pipeline, 5-low-carbon dioxide flue gas inlet valve, 6-carbonization kettle, 7-steel slag product, 8-stainless steel rack, 9-water treatment device, 10-steam outlet pipe, 11-water inlet pipe, 12-water inlet valve, 13-carbon dioxide concentration detector, 14-pressure gauge, 15-reactor venting pipe, 16-reactor venting valve, 17-vacuum pump, 18-reactor exhaust valve. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Figure 1 The device shown is a device for curing steel slag products using low-temperature flue gas, comprising a carbonizing kettle 6 in which a steel slag product 7 is placed.

[0025] Low-temperature carbon dioxide flue gas is introduced into the carbonization kettle 6. A water treatment device 9 is provided at the bottom of the carbonization kettle 6 and is located below the steel slag product 7. The water treatment device 9 is provided with a steam outlet pipe 10 with an outlet located below the steel slag product 7.

[0026] The low-temperature carbon dioxide flue gas includes the low-temperature carbon dioxide flue gas introduced from the upper end of the carbonization kettle 6 into the upper part of the steel slag product 7 through the first low-temperature carbon dioxide flue gas pipeline 3 and the low-temperature carbon dioxide flue gas introduced from the lower side of the carbonization kettle 6 into the water treatment device 9 below the steel slag product 7 through the second low-temperature carbon dioxide flue gas pipeline 4.

[0027] The first low-temperature carbon dioxide flue gas pipeline 3 and the second low-temperature carbon dioxide flue gas pipeline 4 are formed by diverting the low-temperature carbon dioxide flue gas main pipeline 2.

[0028] Both the first low-temperature carbon dioxide flue gas pipeline 3 and the second low-carbon dioxide flue gas pipeline 4 are provided with a low-carbon dioxide flue gas inlet valve 5 .

[0029] A temperature detector 1 is provided on the low-temperature carbon dioxide flue gas main pipeline 2.

[0030] The upper end of the carbonization kettle 6 is connected to a reactor venting pipe 15 with a reactor venting valve 16 , and the lower side of the carbonization kettle 6 is connected to a vacuum pump 17 through a pipeline with a reactor exhaust valve 18 .

[0031] The water treatment device 9 is connected to a water inlet pipe 11 extending to the outside of the carbonization kettle 6 , and the water inlet pipe 11 is provided with a water inlet valve 12 located outside the carbonization kettle 6 .

[0032] The carbonization kettle 6 is provided with a carbon dioxide concentration detector 13 and a pressure gauge 14 .

[0033] Several layers of stainless steel racks 8 for placing steel slag products 7 are provided in the carbonizing kettle 6 .

[0034] The specific implementation steps are as follows:

[0035] Step 1: Steel slag and other raw materials are mixed and molded in a certain ratio. After demolding, a steel slag product 7 is obtained. The steel slag product is placed in a carbonization kettle 6. After tightening the kettle cover screws, the reactor exhaust valve 8 connected to the vacuum pump 9 is opened, the low carbon dioxide flue gas inlet valve 5 and the reactor exhaust valve 16 are closed, and the vacuum pump 17 is started to exhaust the air in the carbonization kettle 6. When the pressure gauge 14 reads -0.85 to -0.9 bar, the opened carbonization kettle exhaust valve 18 and vacuum pump 17 are closed.

[0036] Step 2: After the low-temperature CO2 flue gas (<200°C) is ventilated at the inlet, the temperature detector automatically detects and reads the real-time temperature. Open the low-temperature CO2 flue gas inlet valve 5 of the first low-temperature CO2 flue gas pipeline 3 to allow the CO2 flue gas to enter the carbonization kettle 6. When the pressure gauge 14 reaches the preset pressure value, start timing. During this period, keep the pipeline unobstructed so that the CO2 flue gas can continuously enter the carbonization kettle 6, while drying and carbonizing the steel slag product 7;

[0037] Step 3: During the carbonization curing period, the carbon dioxide concentration of the gas in the carbonization kettle 6 is measured once every 30 to 60 minutes using the carbon dioxide concentration detector 13. When the dial reading stabilizes, the concentration value is read;

[0038] Step 4: End the carbonization curing after 3 to 12 hours from the start time, then close the low-temperature carbon dioxide flue gas inlet valve 5 of the first low-temperature carbon dioxide flue gas pipeline 3, and open the reactor vent valve 16 until the pressure gauge 14 returns to the initial value;

[0039] Step 5: Open the reactor exhaust valve 18 connected to the vacuum pump 17, close the low-CO2 flue gas inlet valve 5 and the reactor exhaust valve 16, start the vacuum pump 17 to extract the air in the carbonization reactor until the pressure gauge reads -0.85 to -0.9 bar, then close the opened carbonization reactor exhaust valve 18 and vacuum pump 17;

[0040] Step 6: When the real-time temperature detected by the temperature detector 1 is 100-200°C, the low-temperature carbon dioxide flue gas inlet valve 5 of the first low-temperature carbon dioxide flue gas pipeline 3 is manually closed and the low-temperature carbon dioxide flue gas inlet valve 5 of the second low-temperature carbon dioxide flue gas pipeline 4 is opened to allow the low-temperature carbon dioxide flue gas to enter the water treatment device 9. Steam will enter the cavity through the steam outlet pipe 10 and then cure the steel slag products above. Open the water inlet valve 12 to maintain the water level inside the water treatment device 9 above the lowest line.

[0041] Step 7: End steam curing after 1 to 12 hours from the start of the timing. Then, close the low-temperature carbon dioxide flue gas inlet valve 5 of the second low-carbon dioxide flue gas pipeline 4, open the reactor vent valve 16 until the pressure gauge returns to the initial value, and take out the steel slag product 7 on the stainless steel rack 8 to obtain a steel slag product with good volume stability.

[0042] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for curing steel slag products using low-temperature flue gas, characterized by: It includes a carbonizing kettle (6) in which a steel slag product (7) is placed. Low-temperature carbon dioxide flue gas is introduced into the carbonization kettle (6). A water treatment device (9) located below the steel slag product (7) is provided at the bottom of the carbonization kettle (6). A steam outlet pipe (10) with an outlet located below the steel slag product (7) is provided on the water treatment device (9). The low-temperature carbon dioxide flue gas includes the low-temperature carbon dioxide flue gas introduced from the upper end of the carbonization kettle (6) into the upper part of the steel slag product (7) through the first low-temperature carbon dioxide flue gas pipeline (3) and the low-temperature carbon dioxide flue gas introduced from the lower side of the carbonization kettle (6) into the water treatment device (9) below the steel slag product (7) through the second low-temperature carbon dioxide flue gas pipeline (4). The first low-temperature carbon dioxide flue gas pipeline (3) and the second low-temperature carbon dioxide flue gas pipeline (4) are formed by diverting the low-temperature carbon dioxide flue gas main pipeline (2). The first low-temperature carbon dioxide flue gas pipeline (3) and the second low-carbon dioxide flue gas pipeline (4) are both provided with a low-carbon dioxide flue gas inlet valve (5); The low-temperature carbon dioxide flue gas main pipeline (2) is provided with a temperature detector (1).

2. The equipment for curing steel slag products using low-temperature flue gas according to claim 1, characterized in that: The upper end of the carbonization kettle (6) is connected to a reactor venting pipe (15) with a reactor venting valve (16), and the lower side of the carbonization kettle (6) is connected to a vacuum pump (17) through a pipeline with a reactor exhaust valve (18).

3. The equipment for curing steel slag products using low-temperature flue gas according to claim 1, characterized in that: The water treatment device (9) is connected to a water inlet pipe (11) extending to the outside of the carbonization kettle (6), and the water inlet pipe (11) is provided with a water inlet valve (12) located outside the carbonization kettle (6).

4. The equipment for curing steel slag products using low-temperature flue gas according to claim 1, characterized in that: The carbonization kettle (6) is provided with a carbon dioxide concentration detector (13) and a pressure gauge (14).

5. The equipment for curing steel slag products using low-temperature flue gas according to claim 1, characterized in that: The carbonizing kettle (6) is provided with several layers of stainless steel racks (8) for placing steel slag products (7).

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