Blast furnace slag waste heat utilization system and method
By designing a blast furnace slag waste heat utilization system, using a multi-stage cooling zone and air supply and air induced mechanism for heat grading and recycling, and combining the grading and utilization module of the waste heat utilization mechanism, the problems of inaccurate cooling and low heat utilization efficiency in the existing system are solved, and efficient waste heat recovery and utilization are achieved, achieving the effect of energy saving and emission reduction.
Patent Information
- Application Number
- CN202411680944.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-03-11
AI Technical Summary
The existing blast furnace slag waste heat utilization system is difficult to achieve precise segmentation cooling, resulting in the inability to effectively recover or be excessively lost in high-temperature waste heat, which reduces the efficiency of waste heat utilization, and lacks effective combination between different functional modules, and the loss is large during heat transfer, making it impossible to achieve efficient energy step transfer and utilization.
A blast furnace slag waste heat utilization system is designed, which includes a blast furnace, a multi-stage cooling zone, a multi-stage air supply and air induced mechanism and a waste heat utilization mechanism. The blast furnace slag is cooled step by step by step through the multi-stage cooling zone and combined with the multi-stage air supply and air induced mechanism to achieve the hierarchical recovery and utilization of heat. The waste heat utilization mechanism uses the exhausted hot air step by step through the coal powder drying zone, heat exchanger, gas preheater and other modules.
It significantly improves the recycling efficiency and utilization efficiency of blast furnace slag waste heat, reduces the consumption of external energy, achieves the goal of energy conservation and emission reduction, and reduces production costs and environmental pollution.
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Figure CN119594739A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of blast furnace slag waste heat treatment, and in particular relates to a blast furnace slag waste heat utilization system and method. Background Art
[0002] Blast furnace slag, as the main by-product produced in the blast furnace smelting process, has a high temperature and heat, accounting for about 20% of the total energy consumption of smelting. For a long time, how to efficiently utilize the waste heat of blast furnace slag has been a technical problem faced by the metallurgical industry. At present, most blast furnace slag cooling methods are mainly water quenching. Although the operation is simple, there are problems such as serious waste of heat energy, huge water consumption and environmental pollution. A small number of dry cooling methods are used to try to recover some of the high-temperature waste heat, but due to unclear heat classification in the cooling process and unreasonable layout of waste heat recovery equipment, the waste heat utilization efficiency is low, which is difficult to meet the energy-saving needs of industrialization.
[0003] In addition, the cascade utilization technology of blast furnace slag waste heat has gradually attracted attention in recent years. Its core concept is to match waste heat of different temperatures to appropriate energy demand areas through segmented cooling and zoning utilization of waste heat, such as high temperature for power generation, medium temperature for drying or baking, and low temperature for preheating coal gas, etc. However, the existing system has the following major problems in practical applications: it is difficult to achieve precise segmented cooling, resulting in some high-temperature waste heat being unable to be effectively recovered or excessively lost, reducing the efficiency of waste heat utilization; there is a lack of effective combination between different functional modules, and the heat loss is large during the transmission process, and it is impossible to achieve efficient energy cascade transfer and utilization; the waste heat utilization rate in the existing solution is insufficient, and it is difficult to significantly reduce the consumption of traditional energy such as coal gas and coal, which limits the realization of energy conservation and emission reduction goals. Summary of the invention
[0004] The purpose of the present invention is to solve the above-mentioned shortcomings and provide a blast furnace slag waste heat utilization system and method.
[0005] In the first aspect, a blast furnace slag utilization system adopts the following technical solution: A blast furnace slag waste heat utilization system, the system comprising: A blast furnace, wherein the blast furnace is used to smelt combustion gas and coal powder to form blast furnace slag; The blast furnace slag cooling mechanism comprises a cooling chamber, wherein a plurality of cooling zones are sequentially connected from top to bottom in the cooling chamber, and the blast furnace slag cooling mechanism is used to discharge the hot air generated after the blast furnace slag is cooled step by step from top to bottom through the plurality of cooling zones, and is also used to discharge the cooled blast furnace slag; A multi-stage air supply and induction mechanism, which is connected to the blast furnace slag cooling mechanism and is used to introduce cold air into the multi-stage cooling zone to exchange heat with the blast furnace slag and then discharge the generated hot air; The waste heat utilization mechanism is connected to the air induction end of the multi-stage air supply and induction mechanism and is used for recycling the hot air discharged step by step.
[0006] Furthermore, the blast furnace also includes a centrifugal granulation bin, one end of which is connected to the blast furnace slag outlet pipe of the blast furnace, and the other end is connected to the blast furnace slag cooling mechanism, and the centrifugal granulation bin is used to granulate the blast furnace slag into smaller particles of blast furnace slag.
[0007] Furthermore, a plurality of impact slopes are staggeredly arranged on the inner wall of the cooling chamber, and the plurality of impact slopes are used to impact the blast-furnace slag to form small particles of blast-furnace slag.
[0008] Furthermore, the outer wall of the cooling chamber adopts a water-cooled wall, and the water-cooled wall is connected to the steam drum pipeline. The water-cooled wall is used to exchange heat with the heat of the cooling chamber and convert it into water vapor to flow into the steam drum for power generation.
[0009] Furthermore, the multi-stage cooling zone includes a primary cooling zone, a secondary cooling zone and a tertiary cooling zone which are sequentially connected from top to bottom; the multi-stage air supply and induction mechanism includes a primary air supply and induction mechanism, a secondary air supply and induction mechanism and a tertiary air supply and induction mechanism; the primary air supply and induction mechanism is connected to the primary cooling zone, the secondary air supply and induction mechanism is connected to the secondary cooling zone, and the tertiary air supply and induction mechanism is connected to the tertiary cooling zone.
[0010] Furthermore, the waste heat utilization mechanism includes a pulverized coal drying area, a heat exchanger, and a coal gas preheater; The tuyere of the pulverized coal drying zone is respectively connected to the induced air end of the three-stage air supply and induced air mechanism and the air inlet pipe of the heat exchanger, and the pulverized coal drying zone is used to provide dry pulverized coal to the blast furnace; The air inlet of the heat exchanger is also connected to the air induction end pipe of the secondary air supply and induction mechanism, and the air outlet of the heat exchanger is connected to the gas preheater. The heat exchanger is used to perform heat exchange between the hot air introduced by the secondary air supply and induction mechanism and the gas waste heat in the coal powder drying area, and provide a heat source for the gas preheater; The gas preheater is also connected to the air induction end of the first-level air supply and induction mechanism.
[0011] Furthermore, the waste heat utilization mechanism also includes an alloy baking zone, the air inlet of the alloy baking zone is connected to the air outlet pipeline of the heat exchanger, and the air outlet of the alloy baking zone is connected to the gas preheater.
[0012] Furthermore, the waste heat utilization mechanism further includes a heating furnace and a gas bunker, wherein the gas bunker is connected to the gas preheater, and the gas bunker is used to store gas and provide gas to the gas preheater; The heating furnace is connected to the coal gas preheater, the air outlet of the heating furnace is connected to the blast furnace pipeline, and the heating furnace is used to heat the coal gas provided by the coal gas preheater.
[0013] In the second aspect, a method for utilizing waste heat from blast furnace slag adopts the following technical solution: A method for utilizing blast furnace slag waste heat, using the above-mentioned blast furnace slag waste heat utilization system to utilize blast furnace slag waste heat, comprising the following process: The blast furnace discharges the smelted blast furnace slag into the blast furnace slag cooling mechanism, and the blast furnace slag is cooled step by step through the multi-stage cooling zones in the cooling chamber and then discharged; the heat of the multi-stage cooling zones is heat exchanged through the multi-stage air supply and exhaust mechanism connected thereto and then led out to the waste heat utilization mechanism for heat utilization.
[0014] Furthermore, the method for utilizing blast furnace slag waste heat specifically includes the following process: The blast furnace slag discharged from the blast furnace is granulated in the centrifugal granulation bin and then enters the blast furnace slag cooling mechanism, and is impact-separated by the impact slope to form small particles of blast furnace slag. The blast furnace slag is cooled in the multi-stage cooling zone of the cooling chamber and then collected; the heat carried by the blast furnace slag is heat-exchanged through the water-cooled wall, and the water is converted into water vapor and flows into the steam drum to provide steam for the power plant; The heat of the primary cooling zone is introduced into the gas preheater through the primary air supply and induction mechanism to provide a heat source for the gas preheater; The heat of the secondary cooling zone is introduced into the heat exchanger through the secondary air supply and induction mechanism to provide a heat source for the alloy baking zone and the gas preheater; The heat from the three-stage cooling zone is introduced into the coal powder drying zone through the three-stage air supply and induction mechanism to dry the coal powder; The coal powder drying zone exchanges heat with the air outlet of the secondary cooling zone through the heat exchanger to provide a heat source for the coal gas preheater, and the hot air after the coal powder drying is introduced into the coal gas preheater to provide a heat source in the alloy baking zone; The coal gas in the coal gas bunker is transported to the coal gas preheater, the preheated coal gas is introduced into the heating furnace for combustion, and the combusted gas and the coal powder in the coal powder drying area are discharged into the blast furnace for smelting.
[0015] Beneficial effects of the present invention: The present invention provides a blast furnace slag waste heat utilization system, which realizes efficient recovery and utilization of blast furnace slag waste heat through the combination of a blast furnace, a blast furnace slag cooling mechanism, a multi-stage air supply and induced draft mechanism and a waste heat utilization mechanism; the blast furnace smelts coal powder and combustion gas to produce blast furnace slag, and combined with the multi-stage cooling zones arranged in the cooling chamber of the blast furnace slag cooling mechanism, the step-by-step cooling process of the blast furnace slag and the heat recovery are carried out synchronously, thereby ensuring the hierarchy and sufficiency of heat utilization; in addition, the multi-stage air supply and induced draft mechanism further enhances the heat exchange efficiency, and introduces cold air for heat exchange with the high-temperature blast furnace slag in the step-by-step cooling zones and discharges the hot air, thereby providing a reliable heat source for subsequent waste heat utilization; through the connection of the waste heat utilization mechanism with the multi-stage air supply and induced draft mechanism, the hot air discharged step by step is recycled to other functional areas, thereby avoiding the problem of direct loss of heat energy in traditional systems and significantly improving the waste heat recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 Schematic diagram of blast furnace slag waste heat utilization system.
[0017] Figure numerals: 1. waste heat utilization system; 10. blast furnace; 11. centrifugal granulation bin; 20. blast furnace slag cooling mechanism; 21. cooling chamber; 211. primary cooling zone; 212. secondary cooling zone; 213. tertiary cooling zone; 22. water-cooled wall; 221. steam drum; 23. impact slope; 24. slag collection zone; 311. primary blower; 312. primary induced draft fan; 321. secondary blower; 322. secondary induced draft fan; 331. tertiary blower; 332. tertiary induced draft fan; 40. pulverized coal drying zone; 50. heat exchanger; 60. gas preheater; 70. alloy baking zone; 80. heating furnace; 90. gas bin. DETAILED DESCRIPTION
[0018] The blast furnace slag waste heat utilization system and method described in the present invention are further described in detail below in conjunction with the examples. For the sake of simplicity of description, this document cannot enumerate all the alternative technical features and implementation schemes contained in the present invention. Therefore, those skilled in the art should know that any technical features and implementation schemes in this embodiment do not limit the scope of protection of the present invention, which includes any alternative technical features and implementation schemes adopted by all those skilled in the art without creative labor. Specifically, the implementation schemes obtained by replacing any technical feature in the present invention or combining any two or more technical features provided by the present invention should be within the scope of protection of the present invention.
[0019] The present invention provides a blast furnace slag waste heat utilization system 1, such as Figure 1 The system includes: A blast furnace 10, the blast furnace 10 is used to smelt combustion-generated gas and coal powder to form blast furnace slag; The blast furnace slag cooling mechanism 20 includes a cooling chamber 21, in which multiple cooling zones are sequentially connected from top to bottom. The blast furnace slag cooling mechanism 20 is used to discharge the hot air generated after the blast furnace slag is cooled step by step through the multiple cooling zones from top to bottom, and is also used to discharge the cooled blast furnace slag; A multi-stage air supply and induction mechanism, which is connected to the blast furnace slag cooling mechanism 20 and is used to introduce cold air into the multi-stage cooling zone to exchange heat with the blast furnace slag and then discharge the generated hot air; The waste heat utilization mechanism is connected to the air induction end of the multi-stage air supply and induction mechanism and is used for recycling the hot air discharged step by step.
[0020] The blast furnace slag waste heat utilization system 1 realizes efficient recovery and cascade utilization of blast furnace slag waste heat through the organic cooperation of the blast furnace 10, the blast furnace slag cooling mechanism 20, the multi-stage air supply and induced draft mechanism and the waste heat utilization mechanism. First, the blast furnace 10 is used to smelt the gas and coal powder produced by combustion to produce high-temperature blast furnace slag, and the smelted blast furnace slag enters the blast furnace slag cooling mechanism 20 through a pipeline; the blast furnace slag cooling mechanism includes a cooling chamber 21, and the chamber is provided with a multi-stage cooling zone connected in sequence from top to bottom. The blast furnace slag passes through the multi-stage cooling zone in sequence from top to bottom, and in this process, heat is exchanged with the cold air sent in by the multi-stage air supply and induced draft mechanism, and the heat is gradually transferred to the cold air, thereby realizing segmented cooling, and the cooled blast furnace slag is discharged from the slag collection area 24 at the bottom.
[0021] The multi-stage air supply and induced draft mechanism is closely connected with the blast furnace slag cooling mechanism 20. The cold air contacts the high-temperature blast furnace slag in each cooling zone, absorbs heat to form hot air, and is discharged through the induced draft end step by step. The graded air supply and heat exchange ensure the temperature gradient distribution of the hot air in different cooling zones, thereby maximizing heat recovery and utilization.
[0022] The exhausted hot air enters the waste heat utilization mechanism through a multi-stage air supply and exhaust mechanism. According to the temperature level of the hot air, the waste heat utilization mechanism applies it to different industrial needs. Through step-by-step cooling, efficient heat exchange and cascade utilization of waste heat, this system significantly improves the utilization efficiency of blast furnace slag waste heat, reduces dependence on external energy, effectively achieves the goal of energy conservation and emission reduction, and at the same time reduces production costs and environmental pollution.
[0023] In some embodiments, the blast furnace 10 also includes a centrifugal granulation bin 11, one end of the centrifugal granulation bin 11 is connected to the blast furnace slag outlet pipe of the blast furnace 10, and the other end is connected to the blast furnace slag cooling mechanism 20. The centrifugal granulation bin 11 is used to granulate the blast furnace slag into smaller particles of blast furnace slag.
[0024] The blast furnace 10 also includes a centrifugal granulation bin 11, one end of which is connected to the blast furnace slag outlet pipe of the blast furnace 10, and the other end is connected to the blast furnace slag cooling mechanism 20. The function of the centrifugal granulation bin 11 is to quickly granulate the high-temperature blast furnace slag into smaller particles of blast furnace slag through centrifugal action. Not only does it increase the specific surface area of the blast furnace slag, but it also effectively improves its cooling performance, so that the blast furnace slag can more efficiently exchange heat with the cold air after entering the blast furnace slag cooling mechanism 20, thereby further improving the cooling effect and heat recovery efficiency.
[0025] In some embodiments, a plurality of impact slopes 23 are staggeredly arranged on the inner wall of the cooling chamber 21 , and the impact slopes 23 are used to impact the blast-furnace slag to form small particles of blast-furnace slag.
[0026] The inner wall of the cooling chamber 21 is staggered with a plurality of impact slopes 23. The impact slopes 23 are used to exert impact on the blast furnace slag through multiple collisions when the blast furnace slag flows through the cooling chamber 21, so as to further separate and granulate the blast furnace slag into smaller particles. The granulation treatment not only optimizes the particle morphology of the blast furnace slag, but also significantly increases the specific surface area of the blast furnace slag, so that it can more efficiently contact with the cold air for heat exchange during the cooling process, thereby improving the cooling efficiency and heat recovery effect.
[0027] In some embodiments, the outer wall of the cooling chamber 21 is a water-cooled wall 22, which is connected to the steam drum 221 through a pipeline. The water-cooled wall 22 is used to exchange heat with the heat of the cooling chamber 21 and convert it into water vapor that flows into the steam drum 221 for power generation.
[0028] The water-cooled wall 22 is connected to the steam drum 221 through a pipeline, and its function is to use the heat generated by the cooling chamber 21 to perform heat exchange with the water inside the water-cooled wall during the cooling process of the blast furnace slag. The water in the water-cooled wall absorbs heat and is converted into water vapor, which is transported to the steam drum 221 through a pipeline. The generated high-temperature and high-pressure steam is further transported to the power generation device to drive the turbine to generate electricity. Not only is the heat emitted by the outer wall during the cooling process of the blast furnace slag efficiently recovered, but it is also converted into electrical energy, realizing the secondary utilization of thermal energy resources and further improving the overall energy utilization efficiency of the system.
[0029] In some embodiments, the multi-stage cooling zone includes a primary cooling zone 211, a secondary cooling zone 212 and a tertiary cooling zone 213 which are sequentially connected from top to bottom; the multi-stage air supply and induction mechanism includes a primary air supply and induction mechanism, a secondary air supply and induction mechanism and a tertiary air supply and induction mechanism; the primary air supply and induction mechanism is connected to the primary cooling zone 211, the secondary air supply and induction mechanism is connected to the secondary cooling zone 212, and the tertiary air supply and induction mechanism is connected to the tertiary cooling zone 213. Furthermore, the first-level air supply and induced draft mechanism includes a first-level supply air fan 311 and a first-level induced draft fan 312, and the first-level supply air fan 311 and the first-level induced draft fan 312 are respectively connected to the pipeline of the first-level cooling zone 211; the second-level air supply and induced draft mechanism includes a second-level supply air fan 321 and a second-level induced draft fan 322, and the second-level supply air fan 321 and the second-level induced draft fan 322 are respectively connected to the pipeline of the second-level cooling zone 212; the third-level air supply and induced draft mechanism includes a third-level supply air fan 331 and a third-level induced draft fan 332, and the third-level supply air fan 331 and the third-level induced draft fan 332 are respectively connected to the pipeline of the third-level cooling zone 213.
[0030] The multi-stage cooling zone includes a primary cooling zone 211, a secondary cooling zone 212 and a tertiary cooling zone 213 which are connected in sequence from top to bottom to realize step-by-step cooling of blast furnace slag. Each cooling zone corresponds to an air supply and induction mechanism, namely a primary air supply and induction mechanism, a secondary air supply and induction mechanism and a tertiary air supply and induction mechanism, which are used to supply cold air to the corresponding cooling zone and discharge hot air. Specifically: The primary air supply and exhaust mechanism includes a primary air supply fan 311 and a primary exhaust fan 312, which are connected to the primary cooling zone 211 through a pipeline to supply cold air to the cooling zone and exhaust hot air; The secondary air supply and exhaust mechanism includes a secondary air supply fan 321 and a secondary exhaust fan 322, which are connected to the secondary cooling zone 212 through a pipeline and are responsible for air supply and hot air exhaust in the cooling zone; The three-stage air supply and exhaust mechanism includes a three-stage air supply fan 331 and a three-stage exhaust fan 332, which are connected to the three-stage cooling zone 213 through pipelines to complete the introduction of cold air and the exhaust of hot air.
[0031] The multi-stage cooling zone and the corresponding air supply and induced draft mechanism realize the zoned and stepped recovery of the heat of the blast furnace slag, so that the high-temperature slag can fully release the heat in the step-by-step cooling process. The hot air in each cooling zone is collected in sections and introduced into the subsequent waste heat utilization system through the corresponding air supply and induced draft mechanism, providing a graded heat source for purposes such as coal powder drying and coal gas preheating, thereby effectively improving the utilization efficiency of waste heat and the overall energy saving effect of the system.
[0032] In some embodiments, the waste heat utilization mechanism includes a pulverized coal drying area 40, a heat exchanger 50, and a coal gas preheater 60; The tuyere of the pulverized coal drying area 40 is respectively connected to the induced air end of the three-stage air supply and induced air mechanism 332 and the air inlet pipe of the heat exchanger 50. The pulverized coal drying area 40 is used to provide dry pulverized coal to the blast furnace 10. The air inlet of the heat exchanger 50 is also connected to the air induction end pipe of the secondary air supply and induction mechanism 322, and the air outlet of the heat exchanger 50 is connected to the gas preheater 60. The heat exchanger 50 is used to heat exchange the hot air drawn out by the secondary air supply and induction mechanism 322 with the gas waste heat of the coal powder drying area 40, and provide a heat source for the gas preheater 60; The gas preheater 60 is also connected to the induced air end of the first-level air supply and induced air mechanism 312 .
[0033] The waste heat utilization mechanism includes a pulverized coal drying area 40, a heat exchanger 50 and a coal gas preheater 60. Each utilization mechanism is connected to a corresponding air supply and exhaust mechanism through a pipeline to achieve graded utilization of waste heat: The air outlet of the pulverized coal drying zone 40 is respectively connected to the induced air end of the three-stage air supply and induced air mechanism 332 and the air inlet pipe of the heat exchanger 50. The hot air generated in the three-stage cooling zone 213 enters the pulverized coal drying zone 40 through the three-stage induced draft fan 332 of the three-stage air supply and induced air mechanism, providing a heat source for the drying of the pulverized coal. The dried pulverized coal is transported to the blast furnace 10 and used as an efficient fuel for smelting, thereby enhancing the combustion efficiency.
[0034] The air inlet of the heat exchanger 50 is connected to the induced draft end pipe of the secondary induced draft fan 322 of the secondary air supply and induced draft mechanism, and is used to receive the hot air discharged from the secondary cooling zone 212 and the waste heat gas discharged from the pulverized coal drying zone 40. The heat exchanger 50 further exchanges heat between the hot air of the secondary cooling zone 212 and the pulverized coal drying zone 40 through heat transfer, providing a stable heat source and improving the utilization rate of thermal energy.
[0035] The hot air after heat exchange enters the gas preheater 60 through the air outlet of the heat exchanger 50, providing a heat source for it. The gas preheater 60 is also connected to the induced draft end of the primary induced draft fan 312 of the primary air supply and induced draft mechanism, and the hot air generated in the primary cooling zone 211 also enters the gas preheater 60 as an auxiliary heat source, further improving the gas preheating effect.
[0036] Through the above configuration, the hot air from the three-stage cooling zone is used for coal powder drying, the hot air from the two-stage cooling zone and the waste heat of the gas discharged from the coal powder drying zone together provide heat sources for the heat exchanger, and the high-temperature hot air after heat exchange provides heat energy for the gas preheater. Such hierarchical utilization enables the system to achieve the coordinated utilization of excess heat sources, which not only improves the efficiency of waste heat utilization, but also effectively reduces external energy consumption, significantly enhancing the energy-saving effect of the system.
[0037] In some embodiments, the waste heat utilization mechanism further includes an alloy baking zone 70 , an air inlet of the alloy baking zone 70 is connected to an air outlet pipe of the heat exchanger 50 , and an air outlet of the alloy baking zone 70 is connected to a gas preheater 60 .
[0038] The waste heat utilization mechanism also includes an alloy baking zone 70, which is used to further utilize the hot air discharged from the heat exchanger 50 and cooperate with the gas preheater 60 to achieve deep recovery and utilization of waste heat.
[0039] Specifically, the air inlet of the alloy baking area 70 is connected to the air outlet of the heat exchanger 50 through a pipeline, and receives the high-temperature hot air from the secondary induced draft fan 322 of the secondary air supply and induced draft mechanism and the pulverized coal drying area 40 after being processed by the heat exchanger 50, which is used to bake the alloy material. During the baking process, the heat of the hot air is fully absorbed, which not only meets the baking requirements of the alloy material, but also realizes the utilization of high-quality thermal energy.
[0040] The waste heat air after baking is discharged through the air outlet of the alloy baking area 70 and transported to the gas preheater 60 to further participate in the gas preheating process as an auxiliary heat source. This multi-stage heat distribution and waste heat cycle organically combines different waste heat utilization links, maximizes the heat recovery efficiency, ensures that the heat source can be repeatedly used in the system, and ultimately effectively reduces energy consumption and operating costs, while meeting multiple needs in industrial production.
[0041] In some embodiments, the waste heat utilization mechanism further includes a heating furnace 80 and a gas bin 90, the gas bin 90 is connected to the gas preheater 60, and the gas bin 90 is used to store gas and provide gas to the gas preheater 60; The heating furnace 80 is connected to the coal gas preheater 60 , and the air outlet of the heating furnace 80 is connected to the pipeline of the blast furnace 10 . The heating furnace 80 is used to heat the coal gas provided by the coal gas preheater 60 .
[0042] The waste heat utilization mechanism also includes a heating furnace 80 and a gas bin 90, which cooperate with the gas preheater 60 to further improve the waste heat utilization efficiency and provide a stable high-temperature heat source for the system.
[0043] The gas bin 90 is used to store gas and is connected to the gas preheater 60 through a pipeline. The gas bin 90 continuously delivers gas to the gas preheater 60. Before the gas enters the heating furnace 80, the gas is preheated by hot air through the gas preheater 60, thereby reducing energy loss during gas combustion and improving combustion efficiency.
[0044] The heating furnace 80 is connected to the gas preheater 60 through a pipeline, and is used to receive the preheated gas and further heat it. The preheated gas burns in the heating furnace 80 to release high-temperature gas. The air outlet of the heating furnace 80 is connected to the blast furnace 10 through a pipeline, and the high-temperature gas after combustion is transported to the blast furnace 10 to participate in the smelting process, providing additional heat source support for the blast furnace operation.
[0045] By preheating the coal gas and recycling the combustion heat, the utilization efficiency of waste heat is maximized, while reducing the consumption demand of external energy. The coordinated use of the heating furnace 80 and the gas bunker 90 not only stabilizes the supply of heat source, but also provides a more efficient and economical energy solution for blast furnace smelting, further optimizing the energy management and operation cost of the entire system.
[0046] This embodiment also provides a method for utilizing blast furnace slag waste heat, which utilizes the blast furnace slag waste heat utilization system 1, and includes the following processes: The blast furnace 10 discharges the smelted blast furnace slag into the blast furnace slag cooling mechanism 20, and the blast furnace slag is cooled step by step through the multi-stage cooling zones in the cooling chamber 21 and then discharged; the heat of the multi-stage cooling zones is heat exchanged through the multi-stage air supply and exhaust mechanism connected thereto and then led out to the waste heat utilization mechanism for heat utilization.
[0047] Based on the above-mentioned blast furnace slag waste heat utilization system 1, the waste heat of blast furnace slag is efficiently recovered and utilized, which specifically includes the following processes: First, the blast furnace 10 discharges the high-temperature blast furnace slag generated during the smelting process and transports it to the blast furnace slag cooling mechanism 20 through a pipeline. After the blast furnace slag enters the cooling chamber 21, it is cooled step by step through the multi-stage cooling zones arranged inside. In this process, the heat of the blast furnace slag is transferred to the cold air entering the cooling zone through heat exchange, thereby reducing the temperature of the blast furnace slag and generating hot air. The cooled blast furnace slag is finally discharged from the bottom for storage or further processing.
[0048] The hot air generated during the cooling process is transmitted through the multi-stage air supply and induction mechanism corresponding to each cooling zone. Each stage of the air supply and induction mechanism is responsible for extracting the heat from the corresponding cooling zone through heat exchange and transmitting it to the waste heat utilization mechanism to achieve graded utilization of heat.
[0049] Through the organic combination of blast furnace slag cooling, hot air recovery and waste heat zoning utilization, not only the efficient recovery of blast furnace slag waste heat is achieved, but it is also reasonably allocated to coal powder drying, coal gas preheating and other purposes, which greatly improves the efficiency of thermal energy utilization, reduces the consumption of external energy, and achieves the effect of energy conservation and emission reduction.
[0050] In some embodiments, the method for utilizing blast furnace slag waste heat specifically includes the following process: The blast furnace slag discharged from the blast furnace 10 is granulated in the centrifugal granulation bin 11 and then enters the blast furnace slag cooling mechanism 20, and is impact-separated by the impact slope 23 to form small-particle blast furnace slag. The blast furnace slag is cooled in the multi-stage cooling zone of the cooling chamber 21 and then collected; the heat carried by the blast furnace slag is heat-exchanged through the water-cooled wall 22, and the water is converted into water vapor and flows into the steam drum 221 to provide steam for the power plant; The heat of the primary cooling zone 211 is introduced into the gas preheater 60 through the primary air supply and air induction mechanism, providing a heat source for the gas preheater 60; The heat of the secondary cooling zone 212 is introduced into the heat exchanger 50 through the secondary air supply and air induction mechanism, providing a heat source for the alloy baking zone 70 and the gas preheater 60; The heat of the third-stage cooling zone 213 is introduced into the coal powder drying zone 40 through the third-stage air supply and air induction mechanism to dry the coal powder; The coal powder drying area 40 exchanges heat with the air from the secondary cooling area 212 through the heat exchanger 50 to provide a heat source for the coal gas preheater 60, and the hot air from the alloy baking area 70 is introduced into the coal gas preheater 60 to provide a heat source; The coal gas in the coal gas bunker 90 is transported to the coal gas preheater 60, and the preheated coal gas is introduced into the heating furnace 80 for combustion. The combusted gas and the coal powder in the coal powder drying area 40 are discharged into the blast furnace 10 for smelting.
[0051] The high-temperature blast furnace slag discharged from the blast furnace 10 enters the centrifugal granulation bin 11 through a pipeline, and the blast furnace slag is processed by centrifugal action in the granulation bin to granulate it into smaller particles of blast furnace slag to improve the cooling efficiency. Subsequently, the granulated blast furnace slag enters the blast furnace slag cooling mechanism 20, and is impact-separated by the impact slopes 23 staggered in the cooling chamber 21, and further forms small particles of blast furnace slag. In the cooling chamber 21, the blast furnace slag is cooled step by step through the primary cooling zone 211, the secondary cooling zone 212 and the tertiary cooling zone 213 in sequence, and finally collected in the slag collection area 24.
[0052] During the cooling process, the heat carried by the blast furnace slag is exchanged with the water outside the cooling chamber through the water-cooled wall 22. The water is heated and converted into water vapor and flows into the steam drum 221, providing steam for the power plant to drive the turbine to generate electricity.
[0053] During the cooling process, the hot air generated in each cooling zone is drawn out through the corresponding air supply and exhaust mechanism and utilized in different grades: The heat generated in the primary cooling zone 211 enters the gas preheater 60 through the primary air supply and induction mechanism, providing a heat source for the gas preheater; The heat generated in the secondary cooling zone 212 enters the heat exchanger 50 through the secondary air supply and induction mechanism, and provides a heat source for the alloy baking zone 70 and the gas preheater 60; The heat generated in the tertiary cooling zone 213 enters the pulverized coal drying zone 40 through the tertiary air supply and induced draft mechanism, and is used to dry the pulverized coal to provide high-quality fuel for blast furnace smelting.
[0054] During the process of drying the pulverized coal in the pulverized coal drying zone 40, the heat of the generated gas is exchanged with the hot air of the secondary cooling zone 212 through the heat exchanger 50, providing an additional heat source for the gas preheater 60. At the same time, the exhaust gas after using the hot air in the alloy baking zone 70 is also introduced into the gas preheater 60, further improving the utilization efficiency of the waste heat.
[0055] Finally, the gas bin 90 delivers the gas to the gas preheater 60, and after preheating, the gas is delivered to the heating furnace 80 for combustion. The generated high-temperature gas returns to the blast furnace 10 through a pipeline and enters the blast furnace together with the coal powder in the coal powder drying area for smelting.
[0056] In some more specific embodiments, the initial temperature of the blast furnace slag is 1400°C-1600°C, the inlet temperature of the blast furnace slag after centrifugal granulation is 1200°C-1400°C when it is transported to the blast furnace slag cooling mechanism, and the temperature of the discharged blast furnace slag is less than 60°C. The temperature of the blast furnace slag in the primary cooling zone falling into the secondary cooling zone is 800°C-1200°C, the temperature of the blast furnace slag in the secondary cooling zone falling into the tertiary cooling zone is 400°C-800°C, and the initial to slag discharge temperature of the blast furnace slag in the tertiary cooling zone is 60°C-400°C. The air inlet and outlet air volumes of the blower and induced draft fan in the multi-stage air supply and induced draft mechanism are set to 130,000 m according to actual production conditions. 3 / h -180000m 3 / h, the air inlet and outlet volume of the remaining induced draft fans in the waste heat utilization mechanism is 100000 m 3 / h -150000m 3 / h.
[0057] Assume that the blast furnace slag output of a steel enterprise is 1000 tons / day, and the thermal enthalpy value is 1770MJ / t. Through the blast furnace slag cooling device of the present invention, it is estimated that about 80% of heat energy can be recovered. Corresponding primary, secondary and tertiary air supply and induction mechanisms are respectively arranged in the primary, secondary and tertiary cooling zones, and the hierarchical utilization of heat energy is realized through pipeline connection. The blast furnace slag cooling device can reduce the energy consumption of the enterprise by about 15%, saving millions of yuan in costs annually.
[0058] For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here, and the obvious changes or modifications derived from them are still within the scope of protection of the claims of the invention.
Claims
1. A blast furnace slag waste heat utilization system, characterized in that: The system includes: A blast furnace, wherein the blast furnace is used to smelt combustion gas and coal powder to form blast furnace slag; The blast furnace slag cooling mechanism comprises a cooling chamber, wherein a plurality of cooling zones are sequentially connected from top to bottom in the cooling chamber, and the blast furnace slag cooling mechanism is used to discharge the hot air generated after the blast furnace slag is cooled step by step from top to bottom through the plurality of cooling zones, and is also used to discharge the cooled blast furnace slag; A multi-stage air supply and induction mechanism, which is connected to the blast furnace slag cooling mechanism and is used to introduce cold air into the multi-stage cooling zone to exchange heat with the blast furnace slag and then discharge the generated hot air; The waste heat utilization mechanism is connected to the air induction end of the multi-stage air supply and induction mechanism and is used for recycling the hot air discharged step by step.
2. A blast furnace slag waste heat utilization system according to claim 1, characterized in that: The blast furnace also includes a centrifugal granulation bin, one end of which is connected to the blast furnace slag outlet pipe of the blast furnace, and the other end is connected to the blast furnace slag cooling mechanism. The centrifugal granulation bin is used to granulate the blast furnace slag into smaller particles of blast furnace slag.
3. A blast furnace slag waste heat utilization system according to claim 1, characterized in that: The inner wall of the cooling chamber is staggeredly provided with a plurality of impact slopes, and the plurality of impact slopes are used to impact blast-furnace slag to form small particles of blast-furnace slag.
4. A blast furnace slag waste heat utilization system according to claim 1, characterized in that: The outer wall of the cooling chamber is a water-cooled wall, which is connected to the drum pipeline. The water-cooled wall is used to exchange heat with the heat of the cooling chamber and convert it into water vapor to flow into the drum for power generation.
5. A blast furnace slag waste heat utilization system according to claim 1, characterized in that: The multi-stage cooling zone includes a primary cooling zone, a secondary cooling zone and a tertiary cooling zone which are sequentially connected from top to bottom; the multi-stage air supply and induction mechanism includes a primary air supply and induction mechanism, a secondary air supply and induction mechanism and a tertiary air supply and induction mechanism; the primary air supply and induction mechanism is connected to the primary cooling zone, the secondary air supply and induction mechanism is connected to the secondary cooling zone, and the tertiary air supply and induction mechanism is connected to the tertiary cooling zone.
6. A blast furnace slag waste heat utilization system according to claim 5, characterized in that: The waste heat utilization mechanism includes a pulverized coal drying area, a heat exchanger, and a coal gas preheater; The tuyere of the pulverized coal drying zone is respectively connected to the induced air end of the three-stage air supply and induced air mechanism and the air inlet pipe of the heat exchanger, and the pulverized coal drying zone is used to provide dry pulverized coal to the blast furnace; The air inlet of the heat exchanger is also connected to the air induction end pipe of the secondary air supply and induction mechanism, and the air outlet of the heat exchanger is connected to the gas preheater. The heat exchanger is used to perform heat exchange between the hot air introduced by the secondary air supply and induction mechanism and the gas waste heat in the coal powder drying area, and provide a heat source for the gas preheater; The gas preheater is also connected to the air induction end of the first-level air supply and induction mechanism.
7. A blast furnace slag waste heat utilization system according to claim 6, characterized in that: The waste heat utilization mechanism also includes an alloy baking zone, the air inlet of the alloy baking zone is connected to the air outlet pipeline of the heat exchanger, and the air outlet of the alloy baking zone is connected to the gas preheater.
8. A blast furnace slag waste heat utilization system according to claim 7, characterized in that: The waste heat utilization mechanism also includes a heating furnace and a gas bin, wherein the gas bin is connected to the gas preheater, and the gas bin is used to store gas and provide gas to the gas preheater; The heating furnace is connected to the coal gas preheater, the air outlet of the heating furnace is connected to the blast furnace pipeline, and the heating furnace is used to heat the coal gas provided by the coal gas preheater.
9. A method for utilizing waste heat from blast furnace slag, characterized in that: The blast furnace slag waste heat utilization system as claimed in claim 8 is used to utilize the blast furnace slag waste heat, including the following process: The blast furnace discharges the smelted blast furnace slag into the blast furnace slag cooling mechanism, and the blast furnace slag is cooled step by step through the multi-stage cooling zones in the cooling chamber and then discharged; the heat of the multi-stage cooling zones is heat exchanged through the multi-stage air supply and exhaust mechanism connected thereto and then led out to the waste heat utilization mechanism for heat utilization.
10. A method for utilizing blast furnace slag waste heat according to claim 9, characterized in that: The method for utilizing waste heat from blast furnace slag specifically comprises the following steps: The blast furnace slag discharged from the blast furnace is granulated in the centrifugal granulation bin and then enters the blast furnace slag cooling mechanism, and is impact-separated by the impact slope to form small particles of blast furnace slag. The blast furnace slag is cooled in the multi-stage cooling zone of the cooling chamber and then collected; the heat carried by the blast furnace slag is heat-exchanged through the water-cooled wall, and the water is converted into water vapor and flows into the steam drum to provide steam for the power plant; The heat of the primary cooling zone is introduced into the gas preheater through the primary air supply and induction mechanism to provide a heat source for the gas preheater; The heat of the secondary cooling zone is introduced into the heat exchanger through the secondary air supply and induction mechanism to provide a heat source for the alloy baking zone and the gas preheater; The heat from the three-stage cooling zone is introduced into the coal powder drying zone through the three-stage air supply and induction mechanism to dry the coal powder; The coal powder drying zone exchanges heat with the air outlet of the secondary cooling zone through the heat exchanger to provide a heat source for the coal gas preheater, and the hot air after the coal powder drying is introduced into the coal gas preheater to provide a heat source in the alloy baking zone; The coal gas in the coal gas bunker is transported to the coal gas preheater, the preheated coal gas is introduced into the heating furnace for combustion, and the combusted gas and the coal powder in the coal powder drying area are discharged into the blast furnace for smelting.