Energy-saving waste heat recovery system based on water vapor closed cycle and high-temperature steel slag sensible heat utilization

Abstract

The invention discloses an energy-saving waste heat recovery system based on water vapor closed cycle and high-temperature steel slag sensible heat utilization, and relates to the technical field of steel slag waste heat recovery, the energy-saving waste heat recovery system comprises a steel slag crushing unit, a steel slag waste heat release unit, a steam-water separation unit and a pipeline adjusting unit. The system is high in heat utilization rate, a large amount of steam can be generated in the treatment process, condensate water obtained in the treatment process can be completely collected and recycled due to closed-loop operation of the system, the water-saving benefit is remarkable, secondary pollution is avoided, and the system also has excellent environment-friendly performance, runs in a fully-closed environment, is free of flying dust, and is suitable for industrial production. And meanwhile, the system adaptability is high, liquid-state, solid-state and semi-molten steel slag can be treated, and slag-iron separation and stabilization treatment are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of steel slag waste heat recovery, and in particular to an energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag. Background Art

[0002] An energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag mainly constructs a closed-loop collaborative process integrating thermal energy conversion, fluid regulation and slag stabilization through efficient recovery and steaming of sensible heat of hot steel slag. Patent application number 202021467717.4 discloses "A steel slag waste heat recovery system, characterized in that the system includes a body, a slag feeding device, a slag unloading device, a thermal imaging window, an automatic pressure relief device, a water supply device, a waste heat boiler, a slag spreading and pouring device, a steel slag temperature measuring device, a slag skin breaking device, Lan The charcoal weighing and conveying device and the semi-coke spraying device are installed. The waste heat boiler is installed directly above the slag spreading and pouring device. The slag spreading and pouring device spreads the high-temperature molten slag into a flat slag layer on the grate chain plate and pours the low-temperature slag into the slag discharging device after heat recovery. The slag skin breaking device is a reciprocating transmission mechanism equipped with a plow-type knife to break the slag skin on the surface of the slag layer. The semi-coke weighing and conveying device is connected to the semi-coke spraying device and sprays the semi-coke into the slag. This steel slag waste heat recovery system has a reasonable process, a continuous and reliable process, low operating cost, and low investment. It is suitable for the steel slag waste heat recovery process in steel enterprises.

[0003] The above-mentioned existing system solves the problem of being unable to recover the waste heat of steel slag. However, when the system is running, due to the lack of a heat exchange structure, a large amount of sensible heat of the steel slag is wasted, and a large amount of high-temperature dusty steam is generated during the treatment process, which contains particulate matter, alkaline oxides, heavy metal dust, etc. Direct discharge poses a threat to both operators and the atmospheric environment. The system lacks a closed loop, consumes a large amount of water resources, steam condensate cannot be recovered, and the steel slag treatment is discontinuous. The phenomenon of mixed flow of hot and cold slag is prominent, affecting the subsequent stabilization process. Summary of the Invention

[0004] The object of the present invention is to provide an energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solutions: an energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag, comprising a pipeline regulating unit;

[0006] The slag crushing unit introduces the high-temperature slag from the converter and electric furnace sections into the granulation zone via a dedicated tipping car. The slag in the granulation zone is evenly crushed by a rolling device. The crushed granular slag is then stably conveyed to the intermediate bin via a chain conveyor. The intermediate bin then evenly conveys the slag into the horizontal cylindrical heat exchanger.

[0007] The steel slag waste heat release unit, a horizontal cylindrical heat exchanger in the unit, absorbs the sensible heat of the high-temperature steel slag through heat exchange and rapidly vaporizes it. A radial three-blade guide stirring blade structure is provided on the inner wall of the heat exchanger cylinder to push the steel slag forward along a spiral trajectory on the inner wall;

[0008] The steam-water separation unit releases sensible heat from the high-temperature steel slag in the horizontal cylindrical heat exchanger, heating the feed water in the pipeline to form a steam-water mixture flow. The steam-water mixture flows through the steam-water separation device and is separated into steam and condensed water. The steam is stably output through the steam main pipe, and the condensed water is pressurized and transported to the front end of the horizontal cylindrical heat exchanger by the return water pump.

[0009] Preferably, the steel slag crushing unit includes a steel slag import module and a material processing module. The steel slag import module introduces the high-temperature steel slag from the converter and electric furnace sections into the granulation zone through a special dump truck, wherein the temperature of the steel slag is 1100 degrees Celsius to 1300 degrees Celsius. The material processing module uses a rolling device to evenly crush the steel slag in the granulation zone to less than 60 mm. The rolling device is provided with multiple groups of high-strength maces, and a small amount of water mist is used during the rolling process to ensure that the final temperature after crushing is 800 degrees Celsius.

[0010] Preferably, the steel slag crushing unit also includes a steel slag conveying module, which stably delivers the compacted granular steel slag into the intermediate bin via a chain conveyor. The intermediate bin is equipped with a high-temperature resistant lining and a temperature control buffer device to ensure continuous and uniform feeding of the steel slag and effectively avoid heat loss. A quantitative feeder is provided at the bottom of the intermediate bin to evenly deliver the steel slag into the horizontal cylindrical heat exchanger.

[0011] Preferably, the steel slag waste heat release unit includes a sensible heat exchange module and a steel slag stirring module. The steel slag in the sensible heat exchange module enters the horizontal cylindrical heat exchanger. Since the total length of the horizontal cylindrical heat exchanger is 19000 mm, the inner diameter of the cylinder is 2400 mm, and it is provided with multiple support rollers and an integrated drive motor, and the heat exchanger shell is provided with a high-strength sealed water-cooled jacket for maintaining the efficient flow of circulating soft water, the soft water circulating in the jacket absorbs the sensible heat of the high-temperature steel slag through heat exchange and quickly vaporizes, the steel slag stirring module is installed with rows of membrane water-cooled tube bundles on the inner wall of the cylinder of the horizontal cylindrical heat exchanger, and is provided with a radial three-piece guide stirring blade structure to push the steel slag forward along the spiral trajectory of the inner wall, thereby enhancing the heat exchange efficiency and preventing local accumulation and agglomeration.

[0012] Preferably, the steel slag waste heat release unit also includes a slag diversion module, in which the steel slag forms a spiral propulsion path in the cylinder, increasing the heat transfer area and contact time, and the double water-cooling structure of the inner and outer walls effectively controls the thermal stress of the cylinder, thereby improving the safety of system operation.

[0013] Preferably, the steam-water separation unit includes a mixture generation module and a steam transmission module. The water supplied to the mixture generation module in the heating pipe absorbs the sensible heat released by the high-temperature steel slag in the horizontal cylindrical heat exchanger and then vaporizes to form a steam-water mixture flowing out of the heat exchanger. The steam transmission module separates the steam-water mixture into steam and condensed water after it flows through the steam-water separation device, and outputs a part of the steam stably to the outside through the steam main pipe, and the remaining steam is transmitted to the deaeration water tank through the steam main pipe.

[0014] Preferably, the steam-water separation unit also includes a condensate treatment module and a feed water deoxygenation module. The condensate treatment module removes impurities from the condensate obtained after steam-water separation through a multi-stage filter and then enters the relay water pool. The feed water deoxygenation module deoxygenates the condensate in the relay water pool to remove corrosive gases. The deoxygenated water obtained after treatment is pressurized and returned to the water inlet end of the horizontal cylindrical heat exchanger through a return pump to form a closed water circulation system.

[0015] Preferably, the pipeline regulating unit automatically adjusts the steam pipeline pressure difference through the ΔP regulating valve according to the steam generation rate and heat load changes, ensuring a stable heat exchange process, continuous steam output, no backflow and fluctuation in the water channel, and ensuring the thermal balance of the system and overall operation safety.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention has a high sensible heat utilization rate and can generate a large amount of steam during the treatment process. Moreover, since the system operates in a closed loop, all the condensed water obtained during the treatment process will be collected for recycling, with significant water-saving benefits and avoiding secondary pollution. The system also has excellent environmental performance, operates in a fully enclosed environment, is dust-free, and has clean steam. At the same time, the system has strong adaptability and can process liquid, solid, and semi-molten steel slag to achieve slag-iron separation and stabilization treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Provides a schematic diagram of the overall system flow for an embodiment of the present invention;

[0019] Figure 2 A block diagram of the internal modules of a slag crushing unit provided in an embodiment of the present invention;

[0020] Figure 3 A block diagram of the internal modules of a steam-water separation unit provided in an embodiment of the present invention;

[0021] Figure 4 A schematic diagram of the overall system framework provided by an embodiment of the present invention;

[0022] Figure 5 A schematic structural diagram of a horizontal cylindrical heat exchanger provided in an embodiment of the present invention.

[0023] In the figure: 1. Steel slag crushing unit; 101. Steel slag inlet module; 102. Material processing module; 103. Steel slag conveying module; 2. Steel slag waste heat release unit; 201. Sensible heat exchange module; 202. Steel slag stirring module; 203. Slag discharge diversion module; 3. Steam-water separation unit; 301. Mixture generation module; 302. Steam transmission module; 303. Condensate treatment module; 304. Feed water deoxygenation module; 4. Pipeline regulation unit. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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.

[0025] See also Figure 1-Figure 5 , the present invention provides a technical solution: an energy-saving waste heat recovery system based on closed-loop water vapor circulation and sensible heat utilization of high-temperature steel slag, including a pipeline regulating unit 4;

[0026] The slag crushing unit 1 introduces the high-temperature slag from the converter and electric furnace sections into the granulation area through a special dump truck. The slag in the granulation area is evenly crushed by a rolling device. The crushed granular slag is then stably conveyed to the intermediate bin by a chain conveyor. The intermediate bin then evenly conveys the slag into the horizontal cylindrical heat exchanger.

[0027] The steel slag waste heat release unit 2 is a horizontal cylindrical heat exchanger that absorbs the sensible heat of the high-temperature steel slag through heat exchange and quickly vaporizes it. A radial three-piece guide stirring blade structure is provided on the inner wall of the heat exchanger to push the steel slag forward along the spiral trajectory of the inner wall;

[0028] Steam-water separation unit 3, the high-temperature steel slag in the steam-water separation unit 3 releases sensible heat in the horizontal cylindrical heat exchanger, heating the water in the pipeline to form a steam-water mixed flow. The steam-water mixture flows through the steam-water separation device and is separated into steam and condensed water. The steam is stably output through the steam main pipe, and the condensed water is pressurized and transported to the front end of the horizontal cylindrical heat exchanger through the return water pump.

[0029] The slag crushing unit 1 includes a slag introduction module 101 and a material processing module 102. The slag introduction module 101 introduces high-temperature slag from the converter and electric furnace sections into the granulation zone via a dedicated dump truck. The slag temperature is 1100 to 1300 degrees Celsius. The material processing module 102 uses a rolling device to uniformly crush the slag in the granulation zone to less than 60 mm. The rolling device is equipped with multiple sets of high-strength maces. A small amount of water mist is used during the rolling process to ensure that the final temperature after crushing is 800 degrees Celsius.

[0030] The slag crushing unit 1 also includes a slag conveying module 103. The slag conveying module 103 stably conveys the compacted granular slag into the intermediate bin via a chain conveyor. The intermediate bin is equipped with a high-temperature resistant lining and a temperature control buffer device to ensure continuous and uniform feeding of the slag and effectively prevent heat loss. A quantitative feeder is provided at the bottom of the intermediate bin to evenly feed the slag into the horizontal cylindrical heat exchanger.

[0031] The steel slag waste heat release unit 2 includes a sensible heat exchange module 201 and a steel slag stirring module 202. In the sensible heat exchange module 201, the steel slag enters the horizontal cylindrical heat exchanger. Since the horizontal cylindrical heat exchanger has a total length of 19,000 mm and an inner diameter of the cylinder is 2,400 mm, it is provided with multiple support rollers and an integrated drive motor. The heat exchanger shell is provided with a high-strength sealed water-cooling jacket to maintain the efficient flow of circulating soft water. The soft water circulating in the jacket absorbs the sensible heat of the high-temperature steel slag through heat exchange and is quickly vaporized. The steel slag stirring module 202 is installed with a row of membrane water-cooling tube bundles on the inner wall of the cylinder of the horizontal cylindrical heat exchanger, and is provided with a radial three-piece guide stirring blade structure to push the steel slag forward along the spiral trajectory of the inner wall, thereby enhancing the heat exchange efficiency and preventing local accumulation and agglomeration.

[0032] The slag waste heat release unit 2 also includes a slag discharge and diversion module 203. The slag in the slag discharge and diversion module 203 forms a spiral propulsion path in the cylinder, increasing the heat transfer area and contact time. The dual water cooling structure of the inner and outer walls effectively controls the thermal stress of the cylinder and improves the safety of system operation.

[0033] The steam-water separation unit 3 includes a mixture generation module 301 and a steam transmission module 302. The mixture generation module 301 feeds water in the heating pipe, which absorbs the sensible heat released by the high-temperature steel slag in the horizontal cylindrical heat exchanger and then vaporizes to form a steam-water mixture that flows out of the heat exchanger. The steam transmission module 302 separates the steam-water mixture into steam and condensed water after it flows through the steam-water separation device. A portion of the steam is stably output to the outside through the steam main pipe, and the remaining steam is transmitted to the deaeration water tank through the steam main pipe.

[0034] The steam-water separation unit 3 also includes a condensate treatment module 303 and a feed water deoxygenation module 304. The condensate treatment module 303 removes impurities from the condensate obtained after steam-water separation through a multi-stage filter, and then enters the relay water tank. The feed water deoxygenation module 304 deoxygenates the condensate in the relay water tank to remove corrosive gases. The deoxygenated water obtained after treatment is pressurized and returned to the water inlet end of the horizontal cylindrical heat exchanger by a return water pump, forming a closed water circulation system.

[0035] The pipeline regulating unit 4 automatically adjusts the steam pipeline pressure difference through the ΔP regulating valve according to the changes in steam generation rate and heat load, ensuring a stable heat exchange process, continuous steam output, no backflow and fluctuation in the water channel, and ensuring the thermal balance of the system and overall operational safety.

[0036] Working principle: The present invention introduces high-temperature steel slag into the granulation zone through the steel slag introduction module 101 in the steel slag crushing unit 1, and the material processing module 102 uniformly crushes the steel slag in the granulation zone to less than 60 mm. The steel slag is evenly fed into the horizontal cylindrical heat exchanger through the steel slag conveying module 103. The sensible heat exchange module 201 in the steel slag waste heat release unit 2 absorbs the sensible heat of the high-temperature steel slag through heat exchange and rapidly vaporizes it. The steel slag stirring module 202 and the slag discharge and diversion module 203 push the steel slag forward along the spiral trajectory of the inner wall, thereby forming a spiral propulsion path. The mixture generation module 301 in the steam-water separation unit 3 is used to reduce the temperature of the steel slag to below 250°C. The steam transmission module 302 stably outputs steam through the steam main pipe. The condensate treatment module 303 collects the condensate into the relay water tank after multi-stage filtration, deoxygenates it through the feed water deoxygenation module 304, and then is pressurized and conveyed to the front end of the horizontal cylindrical heat exchanger by the return water pump. Finally, the pipeline regulation unit 4 is used to automatically adjust the pressure difference of the steam pipeline.

[0037] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0038] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag, comprising a pipeline regulating unit (4), characterized in that: The slag crushing unit (1) introduces the high-temperature slag from the converter and electric furnace sections into the granulation zone through a special dumper, uses a rolling device to evenly crush the slag in the granulation zone, and then stably sends the crushed granular slag into the intermediate bin through a chain conveyor, and the intermediate bin evenly sends the slag into the horizontal cylindrical heat exchanger; The steel slag waste heat release unit (2) comprises a horizontal cylindrical heat exchanger that absorbs sensible heat of high-temperature steel slag through heat exchange and rapidly vaporizes the slag. A radial three-piece guide stirring blade structure is provided on the inner wall of the heat exchanger cylinder to push the steel slag forward along a spiral trajectory on the inner wall. The steam-water separation unit (3) is a steam-water separation unit in which high-temperature steel slag releases sensible heat in a horizontal cylindrical heat exchanger, heating the feed water in the pipeline to form a steam-water mixed flow. The steam-water mixed flow passes through the steam-water separation device and is separated into steam and condensed water, wherein the steam is stably output through the steam main pipe, and the condensed water is pressurized and transported to the front end of the horizontal cylindrical heat exchanger by a return water pump.

2. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 1 is characterized by: The steel slag crushing unit (1) comprises a steel slag introduction module (101) and a material processing module (102). The steel slag introduction module (101) introduces high-temperature steel slag from the converter and electric furnace sections into the granulation zone through a special dump truck, wherein the temperature of the steel slag is 1100 degrees Celsius to 1300 degrees Celsius. The material processing module (102) uses a rolling device to uniformly crush the steel slag in the granulation zone to less than 60 mm. The rolling device is provided with multiple groups of high-strength maces. A small amount of water mist is used during the rolling process to ensure that the final temperature after crushing is 800 degrees Celsius.

3. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 2 is characterized by: The slag crushing unit (1) further comprises a slag conveying module (103), wherein the slag conveying module (103) stably conveys the granular slag after rolling into an intermediate bin via a chain conveyor. The intermediate bin is provided with a high-temperature resistant lining and a temperature control buffer device, and a quantitative feeder is provided at the bottom to uniformly convey the slag into the horizontal cylindrical heat exchanger.

4. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 1 is characterized by: The steel slag waste heat release unit (2) comprises a sensible heat exchange module (201) and a steel slag stirring module (202). The steel slag in the sensible heat exchange module (201) enters a horizontal cylindrical heat exchanger. Since the horizontal cylindrical heat exchanger has a total length of 19,000 mm and an inner diameter of the cylinder is 2,400 mm, and is provided with a plurality of supporting rollers and an integrated drive motor, and the heat exchanger shell is provided with a high-strength sealed water-cooled jacket, the soft water flowing in the jacket absorbs the sensible heat of the high-temperature steel slag through heat exchange and quickly vaporizes it. The steel slag stirring module (202) is installed with a row of membrane water-cooled tube bundles on the inner wall of the cylinder of the horizontal cylindrical heat exchanger, and is provided with a radial three-piece guide stirring blade structure to push the steel slag forward along the spiral trajectory of the inner wall.

5. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 4 is characterized by: The steel slag waste heat release unit (2) further comprises a slag discharge diversion module (203), wherein the steel slag in the slag discharge diversion module (203) forms a spiral propulsion path in the cylinder, thereby increasing the heat transfer area and contact time, and the dual water cooling structure of the inner and outer walls effectively controls the thermal stress of the cylinder.

6. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 1 is characterized by: The steam-water separation unit (3) includes a mixture generation module (301) and a steam transmission module (302). The mixture generation module (301) feeds water in a heating pipe, absorbs sensible heat released by high-temperature steel slag in a horizontal cylindrical heat exchanger, and then vaporizes to form a steam-water mixture that flows out of the heat exchanger. The steam transmission module (302) separates the steam-water mixture into steam and condensed water after the steam-water mixture flows through the steam-water separation device, and stably outputs a portion of the steam to the outside through a steam main pipe, and the remaining steam is transmitted to a deaeration water tank through the steam main pipe.

7. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 6 is characterized by: The steam-water separation unit (3) further comprises a condensate treatment module (303) and a feed water deoxygenation module (304). The condensate treatment module (303) removes impurities from the condensate obtained after steam-water separation through a multi-stage filter and then enters the relay water pool. The feed water deoxygenation module (304) deoxygenates the condensate in the relay water pool to remove corrosive gases. The deoxygenated water obtained after the treatment is pressurized and returned to the water inlet end of the horizontal cylindrical heat exchanger by a return water pump, thereby forming a closed water circulation system.

8. The energy-saving waste heat recovery system based on closed-loop water vapor circulation and utilization of sensible heat of high-temperature steel slag according to claim 1 is characterized by: The pipeline regulating unit (4) automatically regulates the steam pipeline pressure difference according to the steam generation rate and the heat load change through the ΔP regulating valve, thereby ensuring a stable heat exchange process, continuous steam output, and no backflow or fluctuation in the water channel.

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