Steel slag waste heat recovery and utilization system

Abstract

The utility model provides a steel slag waste heat recovery and utilization system. A rolling cooling bed conveys high-temperature steel slag into the rolling cooling bed through a first conveying device for primary cooling; the grate cooling box body and the rolling cooling bed are connected through a second conveying device for secondary cooling, and the grate cooling box body is further connected with the hot stuffy pool through a third conveying device; the hot stuffy pool is communicated with a room-temperature water storage device, and the boiler is connected with the rolling cooling bed and the grate cooling box body through high-temperature flue gas pipelines so as to recover high-temperature flue gas generated by cooling treatment of the rolling cooling bed and the grate cooling box body; the vacuum phase change direct heating machine is connected with the hot stuffiness pool through a high-temperature water conveying pipe and a normal-temperature water conveying pipe, so that high-temperature slag flushing water fed into the vacuum phase change direct heating machine is subjected to vacuum phase change with normal-temperature water in the vacuum phase change direct heating machine, and the vacuum phase change direct heating machine is connected with the boiler through a high-temperature hot water conveying pipe. And the high-temperature flue gas reheats the high-temperature water fed into the boiler. The device can recover heat energy of the steel slag and digest calcium oxide and magnesium oxide in the steel slag.

Description

TECHNICAL FIELD

[0001] The utility model relates to steel slag waste heat recovery and utilization technical field, concretely is a kind of steel slag waste heat recovery and utilization system. BACKGROUND

[0002] The energy utilization rate of steel enterprise is only about 50%, and a large amount of residual energy has not been fully utilized. Since it is mainly to eliminate heat energy, most of the residual energy exists in the form of heat energy. The high-temperature waste heat resources of steel plant mainly consist of three parts: product waste heat, waste gas waste heat and molten slag waste heat. Among them, the product waste heat and the waste gas waste heat have been effectively recovered, and only the molten slag, especially the steel slag, has no mature recovery technology for industrial application so far.

[0003] Steel slag is a byproduct of converter steelmaking process, and the slag discharge per ton of steel is about 0.14 tons. At present, the amount of steel slag in China exceeds 140 million tons per year, and 1 ton of steel slag contains 1670 MJ of heat, which is equivalent to about 60 kg of standard coal, so about 8.4 million tons of standard coal heat is contained in the discharged steel slag per year. The recovery of steel slag waste heat has become an important means for steel enterprises to achieve energy saving and emission reduction, and has important social, economic and environmental benefits.

[0004] Although steel slag contains a large amount of sensible heat, it is limited by intermittent slagging and current steel slag treatment process. At present, basically steel slag is transported to the designated place by slag truck, and is subjected to slag pit or roller crushing and tank recovery. The slag pit is to pour solid or liquid steel slag into the slag pit, seal it with a slag cover, spray water, crush the slag shell, realize effective separation of slag and steel, and react water vapor with free calcium oxide and magnesium oxide in the slag to eliminate. The roller crushing and tank is to crush by roller, spray liquid to solid, and then use tank to realize the reaction of free calcium oxide and magnesium oxide in the slag to eliminate. The above two recovery and treatment technologies focus on the reaction of free calcium oxide and magnesium oxide in the slag to eliminate, meet the use requirements of cement-based materials, but waste the high-quality waste heat resources contained in the slag, and the heat recovery efficiency is very low. Based on this, it is necessary to improve it and design a steel slag waste heat recovery and utilization system which can realize good heat energy recovery and make free calcium oxide and magnesium oxide react to generate calcium hydroxide and magnesium hydroxide to meet the use requirements of cement-based materials. SUMMARY

[0005] The utility model aims at overcoming the above-mentioned problems existing in prior art, and provides a steel slag waste heat recovery and utilization system which can recover steel slag heat energy and eliminate calcium oxide and magnesium oxide in steel slag.

[0006] The utility model discloses a kind of steel slag waste heat recovery and utilization system, including hot steaming pool and roller pressure cold bed, the roller pressure cold bed is sent into its inside by first conveying device with high-temperature steel slag, to make the high-temperature steel slag sent in in roller pressure cold bed carries out first cooling;Still include:

[0007] grate cooling box, with roller pressure cold bed is connected by second conveying device, to make the high-temperature steel slag sent in in grate cooling box carries out secondary cooling, the grate cooling box is also connected with hot steaming pool by third conveying device, the hot steaming pool is communicated with room temperature water storage device, to make water in room temperature water storage device become high-temperature flushing slag water after being sprayed hot steaming pool, simultaneously, free calcium oxide and magnesium oxide in steel slag in hot steaming pool are digested;

[0008] boiler, by high-temperature flue gas pipeline is connected with roller pressure cold bed and grate cooling box respectively, to recover high-temperature flue gas generated by roller pressure cold bed and grate cooling box cooling treatment;

[0009] vacuum phase-change direct heater, with hot steaming pool is connected by high-temperature water conveying pipe and normal temperature water conveying pipe, to make high-temperature flushing slag water sent into vacuum phase-change direct heater become high-temperature water after vacuum phase change with normal temperature water in vacuum phase-change direct heater, vacuum phase-change direct heater is also connected with boiler by high-temperature hot water conveying pipe, to make high-temperature flue gas heat high-temperature water sent into boiler again.

[0010] Preferably, the boiler is connected with factory power generation steam pipe network

[0011] Preferably, the boiler is connected with cooling device by pipeline, the cooling device is connected with grate cooling box by pipeline, to make high-temperature flue gas in boiler send into cooling device cooling, low-temperature flue gas after cooling is sent to grate cooling box recycling by pipeline.

[0012] Preferably, the cooling device is also connected with first conveying device by pipeline, to make low-temperature flue gas after cooling send to first conveying device and participate in high-temperature steel slag heat exchange.

[0013] Preferably, air inlet is also arranged on the roller pressure cold bed, the air inlet is connected with room temperature air storage unit, for cooling high-temperature steel slag.

[0014] Preferably, normal temperature water inlet is also arranged on the hot steaming pool, the normal temperature water inlet is communicated with room temperature water storage device.

[0015] Preferably, valve is arranged on all pipelines.

[0016] Preferably, the boiler is connected to a high-temperature flue gas collection device via a pipeline, and the high-temperature flue gas collection device is connected to the roller cooling bed and the grate cooling box via high-temperature flue gas pipelines respectively; the boiler is connected to a high-temperature hot water collection device via a pipeline, and the high-temperature hot water collection device is connected to a vacuum phase change direct heat exchanger via a high-temperature hot water delivery pipe.

[0017] Preferably, the vacuum phase change direct heat exchanger is also connected to a water treatment system via a pipeline, and a valve is installed on the pipeline.

[0018] Preferably, the boiler is connected to a dust removal system.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] This invention provides a waste heat recovery and utilization system for steel slag. The system uses a roller cooling bed and a grate cooling box to cool high-temperature steel slag twice, reducing the temperature of the high-temperature steel slag from 1600℃ to 500℃. At this time, the high-temperature flue gas generated by the two cooling processes absorbs the heat released by the cooling of the high-temperature steel slag and sends it into the boiler for utilization. The high-temperature steel slag cooled to 500℃ is sent into a hot quenching tank. Water from a room temperature water storage device is sprayed onto the high-temperature steel slag in the hot quenching tank. The sprayed water exchanges heat with the steel slag in the hot quenching tank to generate high-temperature slag flushing water. At the same time, the sprayed water can dissolve free calcium oxide and magnesium oxide in the steel slag in the hot quenching tank. High-temperature slag flushing water is fed into a vacuum phase change direct heat exchanger, where it undergoes a vacuum phase change with the phase change medium (water). After the phase change heat exchange, the steel slag temperature cools from 500℃ to 80℃. At this point, the room-temperature water in the vacuum phase change direct heat exchanger becomes high-temperature water after the phase change heating. This high-temperature water is then sent into a boiler and reheated by the high-temperature flue gas for reuse. This process not only achieves over 75% waste heat recovery from the steel slag but also decomposes calcium oxide and magnesium oxide in the steel slag.

[0021] The present invention provides a steel slag waste heat recovery and utilization system that integrates air-cooled boiler heat exchange and water-cooled vacuum phase change, thereby realizing the full recovery and utilization of high-temperature steel slag waste heat.

[0022] In this invention, the hot steam heated by the boiler is sent to the factory's power generation steam pipeline network to generate electricity, thus recovering the heat energy from the steel slag.

[0023] The high-temperature flue gas output from the boiler provided by this utility model is cooled to become low-temperature flue gas. The low-temperature flue gas is then transported to the roller cooling bed and grate cooling box through sealed pipelines. This not only realizes the circulation of flue gas, but also allows the low-temperature flue gas to absorb the heat of high-temperature steel slag, thereby improving the heat exchange efficiency. Attached Figure Description

[0024] Figure 1This is a process flow diagram of a steel slag waste heat recovery and utilization system according to this utility model.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Roller cooling bed, 2. Grate cooling box, 3. Hot quenching tank, 4. Vacuum phase change direct heat exchanger, 5. High-temperature steel slag, 6. Room temperature air storage unit, 7. Room temperature water storage device, 8. High-temperature flue gas collection device, 9. High-temperature water conveying pipe, 10. Room temperature water conveying pipe, 11. High-temperature hot water collection device, 12. Boiler, 13. Cooling device, 14. Factory power generation steam pipeline network. Detailed Implementation

[0027] The following is in conjunction with the appendix Figure 1 The specific embodiments of this utility model are described in detail below, but it should be understood that the protection scope of this utility model is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the protection scope of this utility model.

[0028] The inventors discovered that the slag cooling methods of slag pit or roller crushing and slag recovery in slag pots all use water spraying to cool the slag, which cannot effectively recover the waste heat of the slag. Therefore, in response to the above situation, a new waste heat recovery system was invented. This system can improve the utilization of waste heat of slag and also decompose calcium oxide and magnesium oxide in the slag.

[0029] In view of this, the present invention provides a steel slag waste heat recovery and utilization system, which can both recover the heat energy of steel slag and decompose the calcium oxide and magnesium oxide in the steel slag.

[0030] Specific embodiments are shown below, such as Figure 1 This utility model provides a steel slag waste heat recovery and utilization system, including a hot quenching tank 3 and a roller press cooling bed 1. The roller press cooling bed 1 is equipped with a first conveying device to feed high-temperature steel slag 5 into it, so that the fed high-temperature steel slag 5 is cooled once in the roller press cooling bed 1; it also includes:

[0031] The grate cooling box 2 is connected to the roller cooling bed 1 through a second conveying device so that the high-temperature steel slag 5 fed in is cooled twice in the grate cooling box 2. The grate cooling box 2 is also connected to the hot quenching tank 3 through a third conveying device. The hot quenching tank 3 is connected to the room temperature water storage device 7 so that the water in the room temperature water storage device 7 is sprayed into the hot quenching tank 3 and becomes high-temperature slag flushing water, while dissolving the free calcium oxide and magnesium oxide in the steel slag in the hot quenching tank 3.

[0032] Boiler 12 is connected to roller press cooling bed 1 and grate cooling box 2 respectively through high temperature flue gas pipelines to recover the high temperature flue gas generated by the cooling treatment of roller press cooling bed 1 and grate cooling box 2;

[0033] The vacuum phase change direct heat generator 4 is connected to the hot quenching pool 3 through a high-temperature water delivery pipe 9 and a normal-temperature water delivery pipe 10, so that the high-temperature slag flushing water sent into the vacuum phase change direct heat generator 4 becomes high-temperature water after the normal-temperature water in the vacuum phase change direct heat generator 4 undergoes a vacuum phase change. The vacuum phase change direct heat generator 4 is also connected to the boiler 12 through a high-temperature hot water delivery pipe, so that the high-temperature flue gas is reheated and sent into the high-temperature water in the boiler 12.

[0034] In operation, the high-temperature steel slag 5 is rapidly poured into the roller cooling bed 1 via the first conveying device for initial cooling. The cooled steel slag is then conveyed to the grate cooling box 2 via the second conveying device for a second cooling process. The high-temperature flue gas released from the cooled high-temperature steel slag 5 in the roller cooling bed 1 and grate cooling box 2 is sent to the boiler 12 via a high-temperature flue gas pipeline. The cooled high-temperature steel slag 5 is then conveyed to the hot quenching pool 3 via the third conveying device, where it is sprayed with water from the room temperature water storage device 7 for a third cooling process. As the high-temperature steel slag 5 is sprayed in the hot quenching pool 3, the sprayed water forms high-temperature slag flushing water, which also dissolves the free calcium oxide and magnesium oxide in the steel slag in the hot quenching pool 3.

[0035] The high-temperature slag flushing water in the hot quenching tank 3 is sent into the vacuum phase change direct heat exchanger 4, where it undergoes a vacuum phase change heat exchange with the phase change medium (water) inside the vacuum phase change direct heat exchanger 4. This phase change heat exchange transforms the room-temperature water into high-temperature water, which is then transported to the boiler 12 via a high-temperature hot water delivery pipe for use by the boiler. Therefore, this system achieves the recovery and utilization of waste heat from the high-temperature steel slag 5 and the dissolution of calcium oxide and magnesium oxide in the steel slag.

[0036] Specifically, boiler 12 is connected to the factory's power generation steam network 14. The high-temperature steam heated by the high-temperature flue gas sent to boiler 12 is sent to the factory's power generation steam network 14 to generate electricity.

[0037] Specifically, boiler 12 is connected to cooling device 13 via pipeline, and cooling device 13 is connected to grate cooling box 2 via pipeline, so that high-temperature flue gas in boiler 12 is sent to cooling device 13 for cooling, and the cooled low-temperature flue gas is sent to grate cooling box 2 for recycling through pipeline. Low-temperature flue gas serves two purposes: to achieve flue gas circulation and to absorb heat from high-temperature steel slag 5, thereby improving heat exchange efficiency.

[0038] Specifically, the cooling device 13 is also connected to the first conveying device via a pipeline, so that the cooled low-temperature flue gas is sent to the first conveying device to participate in the heat exchange of the high-temperature steel slag 5. The low-temperature flue gas serves two purposes: firstly, to achieve flue gas circulation, and secondly, to absorb the heat from the high-temperature steel slag 5, thereby improving the heat exchange efficiency.

[0039] Specifically, the roller cooling bed 1 is also provided with an air inlet, which is connected to the room temperature air storage unit 6 for cooling the high temperature steel slag 5.

[0040] Specifically, the hot quenching pool 3 is also equipped with a room temperature water inlet. The room temperature water inlet is used to replenish the hot quenching pool 3 with room temperature water.

[0041] Specifically, valves are installed on all pipelines. By setting valves, the waste heat utilization method of the system can be selected, and the flow rate can be controlled to facilitate maintenance.

[0042] Specifically, boiler 12 is connected to high-temperature flue gas collection device 8 via pipelines, and high-temperature flue gas collection device 8 is connected to roller press cooling bed 1 and grate cooling box 2 via high-temperature flue gas pipelines. The purpose is to store high-temperature flue gas for use when there is a need for power generation.

[0043] Specifically, boiler 12 is connected to high-temperature hot water collection device 11 via pipeline, and high-temperature hot water collection device 11 is connected to vacuum phase change direct heat generator 4 via high-temperature hot water delivery pipe. The purpose is to provide sufficient high-temperature hot water when power generation is required.

[0044] Specifically, the vacuum phase change direct heat exchanger 4 is also connected to a water treatment system via a pipeline equipped with valves. The flushing water discharged from the vacuum phase change direct heat exchanger 4 is treated and then discharged to the outside as needed, depending on the operating status of the vacuum phase change direct heat exchanger 4. This serves two purposes: firstly, to control scaling and pipe blockage in the vacuum phase change direct heat exchanger 4; and secondly, to maintain the cleanliness of the flushing water and avoid reducing its heat exchange efficiency.

[0045] Specifically, boiler 12 is connected to a dust removal system. The flue gas inside boiler 12 is treated by dust removal and, depending on the operating conditions of boiler 12, is discharged to the outside as needed. This serves two purposes: firstly, it controls the pressure inside boiler 12, discharging excess flue gas when the pressure reaches a threshold; secondly, it maintains the cleanliness of the flue gas inside boiler 12, preventing it from carrying large amounts of dust and reducing heat exchange efficiency.

[0046] Operating instructions:

[0047] (1) The high-temperature steel slag 5 is quickly poured into the roller cooling bed 1. The steel slag after being treated by the roller cooling bed 1 generates a large amount of high-temperature flue gas. The high-temperature flue gas is located in the upper part of the roller cooling bed 1 and is collected and transported to the boiler 12 through a sealed pipeline. At this time, the temperature of the steel slag in the roller cooling bed 1 is 1600℃~1200℃.

[0048] (2) After being cooled, the steel slag in the roller cooling bed 1 is discharged into the grate cooling box 2 for further cooling. At this time, the steel slag in the grate cooling box 2 can still generate high-temperature flue gas, which is collected and transported to the boiler 12 through a sealed pipeline. At this time, the temperature of the steel slag in the grate cooling box 2 is 1200℃~500℃.

[0049] (3) After cooling, the steel slag in the grate cooling box 2 is discharged into the hot quenching pool 3. The temperature of the steel slag in the hot quenching pool 3 is 500℃~80℃. The water sprayed from the room temperature water storage device 7 sprays the steel slag in the hot quenching pool 3. After absorbing the residual heat of the steel slag, the heated high-temperature slag flushing water is sent into the vacuum phase change direct heat exchanger 4. In the vacuum phase change direct heat exchanger 4, it undergoes a vacuum phase change with the heat exchange medium (water). At this time, the room temperature water in the vacuum phase change direct heat exchanger 4 is heated into high-temperature water through phase change heat exchange. The high-temperature water after heat exchange is sent to the boiler 12 through the high-temperature hot water delivery pipe. The water sprayed from the room temperature water storage device 7 sprays the steel slag in the hot quenching pool 3, which can dissolve the free calcium oxide and magnesium oxide in the steel slag, and generate calcium hydroxide and magnesium hydroxide.

[0050] The high-temperature flue gas collected in steps 1 and 2 above is heated to generate high-temperature steam. This high-temperature steam is sent to the factory's power generation steam network 14 for power generation, realizing the recovery and utilization of steel slag energy. The high-temperature flue gas from the heating boiler 12 is converted into low-temperature flue gas. The low-temperature flue gas is sealed and transported to the grate cooling box 2 through pipelines and fans. The function of the low-temperature flue gas is twofold: to realize the circulation of flue gas and to absorb the heat from the high-temperature steel slag 5, thereby improving heat exchange efficiency. After being heated by the high-temperature steel slag 5, the low-temperature flue gas cools the steel slag and generates high-temperature flue gas again, continuing steps 1 and 2.

[0051] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A steel slag waste heat recovery and utilization system comprising a hot leaching pond (3) and a roller press cold bed (1), characterized in that, The roller cooling bed (1) sends the high-temperature steel slag (5) into its interior through the first conveying device, so that the sent high-temperature steel slag (5) is cooled in the roller cooling bed (1) for the first time; further comprising: The grate cooling box (2) is connected with the roller cooling bed (1) through the second conveying device, so that the sent high-temperature steel slag (5) is cooled in the grate cooling box (2) for the second time, the grate cooling box (2) is further connected with the hot steaming pool (3) through the third conveying device, the hot steaming pool (3) is communicated with the room temperature water storage device (7), so that the water in the room temperature water storage device (7) becomes high-temperature slag flushing water after being sprayed on the hot steaming pool (3), and the free calcium oxide and magnesium oxide in the steel slag in the hot steaming pool (3) are eliminated; The boiler (12) is connected with the roller cooling bed (1) and the grate cooling box (2) through the high-temperature flue gas pipeline respectively, so as to recover the high-temperature flue gas generated by the cooling treatment of the roller cooling bed (1) and the grate cooling box (2); The vacuum phase change direct heater (4) is connected between the hot steaming pool (3) through the high-temperature water conveying pipe (9) and the normal temperature water conveying pipe (10), so that the high-temperature slag flushing water sent into the vacuum phase change direct heater (4) is subjected to vacuum phase change with the normal temperature water in the vacuum phase change direct heater (4), and the normal temperature water becomes high-temperature water, the vacuum phase change direct heater (4) is further connected with the boiler (12) through the high-temperature hot water conveying pipe, so that the high-temperature flue gas heats the high-temperature water sent into the boiler (12) again.

2. The steel slag waste heat recovery and utilization system according to claim 1, characterized in that, The boiler (12) is connected with the factory power generation steam pipe network (14).

3. The steel slag waste heat recovery and utilization system according to claim 2, characterized in that, The boiler (12) is connected with the cooling device (13) through the pipeline, the cooling device (13) is connected with the grate cooling box (2) through the pipeline, so that the high-temperature flue gas in the boiler (12) is sent into the cooling device (13) to be cooled, and the low-temperature flue gas after cooling is sent to the grate cooling box (2) through the pipeline for recycling.

4. The steel slag waste heat recovery and utilization system according to claim 3, characterized in that, The cooling device (13) is further connected with the first conveying device through the pipeline, so that the low-temperature flue gas after cooling is sent to the first conveying device to participate in heat exchange with the high-temperature steel slag (5).

5. The steel slag waste heat recovery and utilization system according to claim 1, characterized in that, An air inlet is further arranged on the roller cooling bed (1) and connected with the room temperature air storage unit (6), which is used for cooling the high-temperature steel slag (5).

6. The steel slag waste heat recovery and utilization system according to claim 3, characterized in that, Valves are arranged on all pipelines.

7. The steel slag waste heat recovery and utilization system according to claim 1, characterized in that, The boiler (12) is connected with the high-temperature flue gas collecting device (8) through the pipeline, the high-temperature flue gas collecting device (8) is connected with the roller cooling bed (1) and the grate cooling box (2) through the high-temperature flue gas pipeline, the boiler (12) is connected with the high-temperature hot water collecting device (11) through the pipeline, and the high-temperature hot water collecting device (11) is connected with the vacuum phase change direct heater (4) through the high-temperature hot water conveying pipe.

8. The steel slag waste heat recovery and utilization system according to claim 1, characterized in that, The vacuum phase change direct heater (4) is further connected with the water treatment system through the pipeline, and a valve is arranged on the pipeline.

9. The steel slag waste heat recovery and utilization system according to claim 1, characterized in that, The boiler (12) is connected with the dust removal system.

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