A system and method for efficiently recovering heat from blast furnace slag and generating electricity

Abstract

The present invention relates to a system and method for efficiently recovering heat from blast furnace slag and generating electricity. The system comprises a slag granulation unit (1), a thermoelectric material power generation unit (2) and a power generation unit (3); the slag granulation unit (1) comprises a turntable granulation chamber (11), a wind crushing granulation chamber (12) and a slag collection bin (13) which are arranged in sequence, and a water cooling bin (19) is arranged outside the turntable granulation chamber (11); the thermoelectric material power generation unit (2) comprises a thermoelectric material arranged between the turntable granulation chamber (11) and the water cooling bin (19); the power generation unit (3) comprises a high-temperature air conduit (31) connected to the turntable granulation chamber (11), a steam conduit (32) connected to the water cooling bin (19) and a hot air conduit (33) connected to the wind crushing granulation chamber (12), and each conduit is connected to a power generation component; blast furnace slag is used as a heat source, air and water are used as heat exchange media, and thermoelectric materials and steam turbines are combined to generate electricity. Compared with the prior art, the present invention can fully utilize the waste heat resources in the blast furnace slag.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace ironmaking waste heat recovery and utilization, and in particular to a system and method for efficiently recovering blast furnace slag heat and generating electricity. Background Art

[0002] As ironmaking waste, most steel mills will use water to flush slag, and then sell the cooled slag as building materials, but this treatment method ignores the value of slag as energy. The heat taken away by blast furnace slag accounts for about 16% of the total heat consumption of the blast furnace. The water flushing treatment method can only utilize about 10% of the heat of the slag. Some steel mills even only use it for cooling and do not use the heat at all. Summary of the invention

[0003] The object of the present invention is to provide a system and method for efficiently recovering heat from blast furnace slag and generating electricity.

[0004] The object of the present invention can be achieved by the following technical solutions: A system for efficiently recovering heat from blast furnace slag and generating electricity, comprising a slag granulation unit, a thermoelectric material power generation unit and a power generation unit;

[0005] The slag granulation unit comprises a turntable granulation chamber, a wind crushing granulation chamber and a slag collection bin which are arranged in sequence, and a water cooling bin is arranged outside the turntable granulation chamber;

[0006] The thermoelectric material power generation unit includes a thermoelectric material arranged between a turntable granulation chamber and a water cooling bin;

[0007] The power generation unit comprises a high-temperature air conduit connected to the turntable granulation chamber, a steam conduit connected to the water cooling bin and a hot air conduit connected to the air crushing granulation chamber, and each conduit is connected to the power generation assembly.

[0008] Preferably, the power generation assembly connected to the high-temperature air duct includes a first heat exchanger, a first steam turbine, a second heat exchanger, a first condenser, a first water pump and a first heat exchanger which are sequentially and cyclically connected.

[0009] Further preferably, the steam conduit is connected to the first steam turbine.

[0010] Preferably, the power generation assembly connected to the hot air duct includes a second heat exchanger, a second steam turbine, a second condenser, a second water pump and a second heat exchanger which are sequentially and cyclically connected.

[0011] Preferably, the high-temperature air duct and the hot air duct are connected to the dust collector and the exhaust duct, and the bottom of the dust collector is connected to the slag collection bin.

[0012] Preferably, a rotary disk granulator is arranged in the rotary disk granulation chamber, a collecting funnel is arranged on the top of the rotary disk granulation chamber, a trapezoidal channel is arranged above the collecting funnel, and air is blown from bottom to top by a high-pressure fan below the rotary disk granulation chamber.

[0013] Further preferably, the high-pressure blower blows air into the wind granulation chamber through the high-pressure air port.

[0014] Preferably, the bottom of the rotary disc granulation chamber is connected to the crushing granulation chamber through a downwardly inclined channel.

[0015] A method for efficiently recovering heat from blast furnace slag and generating electricity is carried out using the above system, using blast furnace slag as a heat source, air and water as heat exchange media, and combining thermoelectric materials and steam turbines to generate electricity.

[0016] Preferably, the method for efficiently recovering heat from blast furnace slag and generating electricity comprises the following steps:

[0017] The liquid high-temperature slag is granulated, re-granulated, cooled and collected in sequence by using the rotary disc granulation chamber, the wind crushing granulation chamber and the slag collection bin;

[0018] Generate electricity using the Seebeck effect of thermoelectric materials;

[0019] The high-temperature air derived from the high-temperature air conduit, the steam derived from the steam conduit, and the hot air derived from the hot air conduit are respectively used to generate electricity through the power generation assembly.

[0020] The research on blast furnace slag heat recovery technology is mainly divided into physical method and chemical method. The physical method is a solid particle waste heat recovery process based on metallurgical slag waste heat recovery; the chemical method uses the heat of slag to provide the required heat for the production of high value-added products. There are several types of blast furnace slag recovery technologies: 1. Ordinary waste heat recovery, 2. Fluidized bed heat recovery. The technologies extending from these two directions include dry granulation technology, wind quenching granulation technology, turntable or cup granulation technology, etc.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention uses blast furnace slag as a heat source, air and water as heat exchange media, and combines thermoelectric materials and steam turbines to generate electricity. In view of the characteristics of blast furnace slag such as high temperature, large heat, and high recovery benefits, the present invention fully utilizes the waste heat resources therein;

[0023] 2. The present invention granulates the high-temperature slag and then uses dual heat exchange with air and water to fully utilize the waste heat resources in the slag. On the one hand, the Seebeck effect of thermoelectric materials is used to utilize the temperature difference between heat transfer media to generate electricity. On the other hand, the heat is converted into mechanical energy through the Rankine cycle to generate electricity, thereby fully utilizing waste energy, reducing resource consumption, and reducing environmental pollution.

[0024] 3. The present invention provides a blast furnace slag waste heat recovery and thermoelectric material and steam turbine power generation system, which can fully recycle and utilize the waste heat in the blast furnace slag, thereby saving electricity costs. In addition, the generated electricity can be fed back to the system and applied to other systems in the steel plant. It can also save energy, protect the environment, and avoid the problem of traditional water slag flushing producing a large amount of harmful gases.

[0025] 4. The present invention solves the problem that blast furnace slag in steel plants is difficult to handle and heat is difficult to utilize, and has practical significance and practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the system of the present invention;

[0027] Figure 2 It is a schematic structural diagram of the slag granulation unit of the present invention;

[0028] Figure 3 It is a structural schematic diagram of the power generation unit of the present invention;

[0029] In the figure: 1-slag granulation unit, 11-rotary disk granulation chamber, 12-wind crushing granulation chamber, 13-slag collection bin, 14-rotary disk granulator, 15-collecting funnel, 16-trapezoidal channel, 17-high pressure fan, 18-high pressure air port, 19-water cooling bin, 110-water injection port switch, 111-control valve, 112-funnel-shaped pipeline, 2-thermoelectric material power generation unit, 3-power generation unit, 31-high temperature air conduit, 32-steam conduit, 33-hot air conduit, 34-first heat exchanger, 35-first steam turbine, 36-second heat exchanger, 37-first condenser, 38-first water pump, 39-second steam turbine, 310-second condenser, 311-second water pump, 312-first conduit, 313-second conduit, 314-third conduit, 315-fourth conduit, 4-dust collector, 5-exhaust conduit. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0031] Example 1

[0032] A system for efficiently recovering heat from blast furnace slag and generating electricity, such as Figures 1 to 3 As shown, it includes a slag granulation unit 1, a thermoelectric material power generation unit 2 and a steam turbine power generation unit 3.

[0033] (1) The slag granulation unit 1 includes three parts. The first part is the turntable granulation chamber 11. When the liquid slag flows into the collecting funnel 15 through the trapezoidal channel 16, the temperature is about 1400°C. Then, it is granulated by the turntable granulator 14 below the funnel. The air is blown from the bottom to the top by the high-pressure fan 17 below the granulation chamber to quickly cool the granulated slag. At the same time, the water cooling bin 19 is closely attached to the outside of the chamber wall to further solidify the liquid slag into granules. At this time, the slag temperature is about 800°C. The second part is the wind crushing granulation chamber 12. After granulation in the first part, the slag particles enter the wind crushing granulation chamber 12 through the downward inclined channel. When entering the chamber, they are blown away by the high-pressure air port 18, which can further granulate the slag while cooling the slag. The third part is the slag collecting bin 13. The temperature of the slag particles after cooling drops to about 100°C and is finally collected into the slag collecting bin 13 through a funnel-shaped pipe 112. The control valve 111 is used to control the falling speed of the slag particles.

[0034] (2) Thermoelectric material power generation unit 2 is operated by thermoelectric materials existing on the wall of the rotary disk granulating chamber 11. When the rotary disk granulator 14 is in operation, the air temperature in the granulating chamber is about 450°C, and the temperature of the slag contacting the wall is about 800-900°C. At this time, the water in the water cooling bin 19 outside the wall is boiling, and steam is generated at a temperature of about 300°C. Thermoelectric materials are installed on both sides of the granulating chamber wall. According to the Seebeck effect, the temperature difference on both sides will cause the transfer of electrons, thereby generating current and achieving the purpose of power generation.

[0035] (3) The steam turbine power generation unit 3 includes a hot air delivery conduit, a medium-pressure steam delivery pipeline, a heat exchanger (boiler), a steam turbine, a condenser, a water pump, and a dust collector. The high-temperature air derived from the high-temperature air conduit 31 has a temperature of approximately 450°C. The high-temperature air first passes through the first heat exchanger (boiler) 34 as a heat source to heat the water inside. The generated medium-pressure steam is introduced into the first steam turbine 35 through the conduit for power generation, and then flows through the second heat exchanger 36 through the first conduit 312 to further utilize the waste heat therein, and then passes through the first condenser 37 for condensation. After condensation into water, it is transported back to the first heat exchanger 34 by the first water pump 38 to complete a Rankine cycle. The medium-pressure steam with a temperature of approximately 300°C derived from the steam conduit 32 is also introduced into the first steam turbine 35 for power generation. The high-temperature air with a temperature of about 200°C led out from the hot air conduit 33 passes through the second heat exchanger (boiler) 36 for heat exchange, and the low-pressure steam generated by the heat exchange is introduced into the second steam turbine 39 through the third conduit 314 for power generation, and then passes through the second condenser 310 and the second water pump 311 in sequence through the fourth conduit 315, and finally returns to the second heat exchanger 36, completing a Rankine cycle. The cascade utilization of the slag waste heat is achieved through two Rankine cycles. The high-temperature air is dedusted by the dust collector 4 and then led out from the exhaust conduit 5. The derived gas can be used for heating, and the filtered dust enters the slag collection bin 13 through the second conduit 313.

[0036] Example 2

[0037] A system and method for efficiently recovering heat from blast furnace slag and generating electricity, using blast furnace slag as a heat source, air and water as heat exchange media, and combining thermoelectric materials and steam turbines to generate electricity.

[0038] The liquid high-temperature slag is first granulated using the rotary disk granulator 14, and then granulated and cooled by the obliquely upward high-pressure air port 18, and finally collected by the slag collection bin 13 below. During the entire granulation process, air is introduced into the rotary disk granulation chamber 11 for heat exchange and cooling, and the hot air is discharged from the upper high-temperature air duct 31; water cooling is performed at the same time, and the generated steam is discharged from the steam duct 32. In the wind crushing granulation chamber 12 below, the slag is further granulated and cooled by the impact of high-speed airflow, and the generated hot air is discharged from the upper hot air duct 33, and the granulated slag is collected by the slag collection bin 13 below.

[0039] The thermoelectric material power generation unit 2 of the present invention generates electricity by utilizing the temperature difference between the turntable granulation chamber 11 and the water cooling chamber 19 outside the chamber wall through the Seebeck effect of the thermoelectric material. A water injection port switch 110 is provided on the top of the water cooling chamber 19.

[0040] The high-temperature air led out of the high-temperature air conduit 31 of the present invention is used to generate electricity. By heat exchange in the first heat exchanger 34 and the second heat exchanger 36, medium-pressure steam and low-pressure steam are generated respectively, and then the heat energy is converted into mechanical energy through the Rankine cycle to generate electricity. The steam led out of the steam conduit 32 enters the first steam turbine 35 together with the steam generated by the first heat exchanger 34 to generate electricity. The high-temperature air conduit 31 passes through the second heat exchanger 36 after the first heat exchange, and the hot air led out of the hot air conduit 33 also passes through the second heat exchanger 36. The steam with residual heat discharged from the first steam turbine 35 in the first Rankine cycle also passes through the second heat exchanger 36 for supplementary heat. The low-pressure steam generated by the second heat exchanger 36 enters the second steam turbine 39 through the third conduit 314 to generate electricity, and then completes a Rankine cycle.

[0041] The present invention relates to waste heat recovery and waste heat power generation of blast furnace slag, which is a slag waste heat recovery combined with a steam turbine and a thermoelectric material combined cycle power generation system. In view of the characteristics of blast furnace slag such as high temperature, large heat and high recovery income, the system of the present invention fully utilizes the waste heat resources therein.

[0042] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A system for efficiently recovering heat from blast furnace slag and generating electricity, characterized in that: It comprises a slag granulation unit (1), a thermoelectric material power generation unit (2) and a power generation unit (3); The slag granulation unit (1) comprises a turntable granulation chamber (11), a wind crushing granulation chamber (12) and a slag collection bin (13) which are arranged in sequence, and a water cooling bin (19) is arranged outside the turntable granulation chamber (11); The thermoelectric material power generation unit (2) comprises a thermoelectric material arranged between a rotary disc granulation chamber (11) and a water cooling chamber (19); The power generation unit (3) comprises a high-temperature air conduit (31) connected to the rotary disc granulation chamber (11), a steam conduit (32) connected to the water cooling bin (19), and a hot air conduit (33) connected to the air granulation chamber (12), and each conduit is connected to a power generation component; The power generation assembly connected to the high-temperature air duct (31) comprises a first heat exchanger (34), a first steam turbine (35), a second heat exchanger (36), a first condenser (37), and a first water pump (38) which are connected in sequence, and the first water pump (38) is further connected to the first heat exchanger (34) to form a cycle; The steam conduit (32) is connected to the first steam turbine (35); The power generation assembly connected to the hot air duct (33) comprises a second heat exchanger (36), a second steam turbine (39), a second condenser (310), and a second water pump (311) which are connected in sequence, and the second water pump (311) is further connected to the second heat exchanger (36) to form a cycle; The high-temperature air conduit (31) is connected in sequence to the first heat exchanger (34) and the second heat exchanger (36).

2. The system for efficiently recovering heat from blast furnace slag and generating electricity according to claim 1 is characterized in that: The high-temperature air duct (31) and the hot air duct (33) are both connected to the dust collector (4) and the exhaust duct (5), and the bottom of the dust collector (4) is connected to the slag collection bin (13).

3. The system for efficiently recovering heat from blast furnace slag and generating electricity according to claim 1, characterized in that: A rotary disk granulator (14) is arranged in the rotary disk granulation chamber (11), a collecting funnel (15) is arranged on the top of the rotary disk granulation chamber (11), a trapezoidal channel (16) is arranged above the collecting funnel (15), and air is blown from bottom to top into the lower part of the rotary disk granulation chamber (11) by a high-pressure fan (17).

4. The system for efficiently recovering heat from blast furnace slag and generating electricity according to claim 3 is characterized in that: The high-pressure fan (17) blows air into the wind granulation chamber (12) through the high-pressure air port (18).

5. The system for efficiently recovering heat from blast furnace slag and generating electricity according to claim 1, characterized in that: The bottom of the rotary disk granulation chamber (11) is connected to the ventilation granulation chamber (12) via a downwardly inclined passage.

6. A method for efficiently recovering heat from blast furnace slag and generating electricity, characterized in that: The system as claimed in any one of claims 1 to 5 is used to generate electricity by combining thermoelectric materials and steam turbines, using blast furnace slag as a heat source, air and water as heat exchange media, and comprising the following steps: The liquid high-temperature slag is sequentially granulated, re-granulated, cooled, and collected using a rotary disk granulation chamber (11), a wind crushing granulation chamber (12), and a slag collection bin (13); Generate electricity using the Seebeck effect of thermoelectric materials; The high-temperature air discharged from the high-temperature air conduit (31), the steam discharged from the steam conduit (32), and the hot air discharged from the hot air conduit (33) are respectively used to generate electricity through the power generation assembly; The high-temperature air discharged from the high-temperature air duct (31) is sequentially heat exchanged in the first heat exchanger (34) and the second heat exchanger (36) to generate medium-pressure steam and low-pressure steam respectively, and then the heat energy is converted into mechanical energy through the Rankine cycle to generate electricity; the steam discharged from the steam duct (32) and the medium-pressure steam generated by the first heat exchanger (34) enter the first steam turbine (35) together to generate electricity; the hot air discharged from the hot air duct (33) passes through the second heat exchanger (36), and the steam with waste heat discharged from the first steam turbine (35) in the first Rankine cycle also passes through the second heat exchanger (36) for supplementary heat; the low-pressure steam generated by the second heat exchanger (36) enters the second steam turbine (39) through the third duct (314) to generate electricity, and then completes a Rankine cycle.

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