CN113008047A - Waste heat recovery and reutilization refining furnace steel scrap preheating device, system and use method - Google Patents

Abstract

The invention discloses a waste heat recycling refining furnace waste steel preheating device, a waste heat recycling refining furnace waste steel preheating system and a using method, and relates to the field of steelmaking; a flashboard with a hole is arranged between the chute and the heating bin; the upper end of one side of the heating bin is provided with a feed inlet, and a high-temperature resistant flashboard is arranged at the feed inlet. The heating bin is arranged, so that the increase of the steel production cost caused by the fact that scrap steel needs to be preheated and is burnt and baked by an air source is overcome, and the increase of equipment cost such as additionally arranging a gas burner is overcome; only the purpose of preheating the scrap steel is achieved by utilizing the recycling of the high-temperature flue gas of the refining furnace and the heat exchange of the scrap steel; the method has the advantages of low cost, simplified scrap steel preheating structure, easy manufacture, low failure rate, safety, reliability, energy conservation, environmental protection and convenient operation.

Description

Waste heat recovery and reutilization refining furnace steel scrap preheating device, system and use method

Technical Field

The invention relates to the field of steelmaking, in particular to a waste heat recycling refining furnace scrap steel preheating device, a waste heat recycling refining furnace scrap steel preheating system and a waste heat recycling refining furnace scrap steel preheating method.

Background

In the process of producing and processing steel in China, the gradual reduction of the proportion of iron ores and the increase of the proportion of scrap steel are the established guidelines of the development policy of the steel industry in China and are the inevitable trends in the development of the steel industry.

The measure for improving the scrap ratio in the prior scrap preheating process is obtained by burning and baking coal gas and a burner, and has the advantages of higher operating cost, higher energy consumption and higher environmental protection pressure.

And the existing scrap steel preheating process can also generate larger waste gas, for example, chinese patent application No. 201810746860.8 discloses a refining furnace scrap steel preheating and feeding device, which also adopts an external heating device such as a burner and gas, although the waste gas in the refining furnace is utilized, the waste gas is only used for controlling the pressure of the preheating furnace, the good utilization of the waste gas is not realized, and the content of the generated waste gas and dust is still higher.

Disclosure of Invention

The invention aims to provide a waste heat recycling refining furnace waste steel preheating device, a waste heat recycling refining furnace waste steel preheating system and a waste heat recycling refining furnace waste steel preheating method, and aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a waste heat recovery and reutilization refining furnace waste steel preheating device comprises a heating bin, wherein a chute is arranged at the bottom of the heating bin and used for sliding down waste steel and leading out smoke, a dust removal pipeline is arranged at the upper end of the heating bin, the tail end of the dust removal pipeline is connected with a dust remover, and a vibration bottom plate is arranged at the bottom of the heating bin;

a flashboard with a hole is arranged between the chute and the heating bin;

the upper end of one side of the heating bin is provided with a feed inlet, and a high-temperature resistant flashboard is arranged at the feed inlet;

the heating chamber is fixed on the supporting frame;

the device also comprises a refining furnace and a material cup for feeding, wherein a traveling crane hanger is arranged at the upper end of the material cup and has a weighing function;

the bottom of the chute is communicated with a furnace cover of the refining furnace, and the chute is also used as a flue to lead out flue gas.

The chute is of a tubular structure or a cuboid structure and is made of heat-resistant and wear-resistant materials.

The middle part of the upper end of the clapboard is provided with a mounting groove for mounting a balancing weight.

Preferably, the heating bin and the vibration bottom plate are made of heat-resistant and wear-resistant materials, and heat-insulating layers are arranged on the outer sides of the heating bin and the vibration bottom plate.

The waste steel preheating method adopting the preheating device for recycling the waste steel of the refining furnace comprises the following steps:

s1, loading required amount of scrap steel into a material cup, hanging the scrap steel onto a charging opening by a traveling crane, opening a high-temperature-resistant flashboard at the moment, closing the flashboard, and enabling the scrap steel to enter a heating bin through the charging opening;

s2, closing the gate plate, fully wrapping the waste steel in the heating bin by high-temperature flue gas led out from the refining furnace, generating 1500 ℃ high-temperature flue gas in the refining furnace, and carrying out heat exchange with the waste steel;

the high-temperature flue gas of the refining furnace is combusted secondarily in the heating bin, the heating bin has the function of a secondary combustion chamber, and carbon monoxide gas generated in the smelting process is combusted in the heating bin and converted into carbon dioxide to generate a large amount of heat energy secondarily;

s3, the scrap steel is used as an initial filter of the waste gas, and most of dust can be collected; preheating the normal-temperature steel scrap to be more than 800 ℃ after about 20-45 minutes, then opening a gate plate, and adding the steel scrap into a refining furnace through a chute;

and S4, feeding the cooled waste gas subjected to heat exchange into an upper dust removal pipeline, continuously smelting by the refining furnace, pulling out the waste gas by a ladle car after the waste gas reaches a tapping standard, then hoisting the waste gas to a continuous casting machine rotary table, and feeding the waste gas into a casting billet drawing process.

Furthermore, the upper end of the dust remover is provided with an air port connected with a dust removal pipeline, a negative plate is arranged on one side of an inner cavity of the dust remover, and an installation shaft is rotatably arranged on the other side of the dust remover;

a plurality of positive plates are arranged on the outer side of the mounting shaft;

the top of the inner cavity of the dust collector is rotatably provided with a positive conductive plate, one side of the positive conductive plate is provided with a first spring, the positive conductive plate is in a vertical state during working and is in contact with a positive plate corresponding to a negative plate, the positive plate is tightly contacted with the positive conductive plate through the first spring, and the positive plate and the negative plate form a dust collection electric field together;

one side of the dust remover, which is provided with the mounting shaft, is provided with an openable door plate;

and an insulating ceramic plate is arranged between the adjacent positive plates.

The utility model provides a waste heat recovery recycles refining furnace steel scrap preheating device which characterized in that: the outside fixed mounting of installation axle has the installing frame, and the installation axle is located the outside one end of dust remover and is provided with the handle.

Preferably, bolt holes are formed in the positive plate and the mounting frame.

Preferably, the two sides of the mounting surface of the mounting frame are both provided with clamping plates, wherein the clamping plate on one side is fixedly connected with the mounting frame, and the clamping plate on the other side is slidably mounted with the mounting frame;

a sliding groove is formed in one side of the mounting frame, and a sliding block capable of sliding in the sliding groove is fixedly mounted at the bottom of the clamping plate on one side;

a second spring for providing tension for the sliding block is arranged between the sliding block and the sliding groove.

The bottom of the chute is communicated with a furnace cover of the refining furnace, and the chute is also used as a flue to lead out flue gas.

The upper end furnace cover of the refining furnace is provided with a hole for mounting the chute.

Compared with the prior art, the invention has the beneficial effects that:

1. the heating bin is arranged, so that the increase of the steel production cost caused by the fact that scrap steel needs to be preheated and is burnt and baked by an air source is overcome, and the increase of equipment cost such as additionally arranging a gas burner is overcome; only the purpose of preheating the scrap steel is achieved by utilizing the recycling of the high-temperature flue gas of the refining furnace and the heat exchange of the scrap steel; the method has the advantages of low cost, simplified scrap steel preheating structure, easy manufacture, low failure rate, safety, reliability, energy conservation, environmental protection and convenient operation.

2. And at the in-process that preheats the scrap steel, refining furnace high temperature flue gas has a postcombustion's process at the heated warehouses, and the heated warehouses has acted as the function of postcombustion room, can play the effect of purifying to the air.

3. In addition, the steel scrap can be used as an initial filter of waste gas, most of dust can be collected, the dust in the waste gas can be subjected to primary treatment, and the difficulty in cleaning the dust in the later period is reduced.

Drawings

FIG. 1 is a schematic view of a preheating apparatus according to the present invention;

FIG. 2 is a sectional view of the preheating system of the present invention;

FIG. 3 is a schematic view of the dust collector of the present invention;

FIG. 4 is a cross-sectional view of a precipitator of the present invention;

FIG. 5 is a schematic structural diagram of a first spring according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another embodiment of the first spring of the present invention;

fig. 7 is a structural view of the positive conductive plate of the present invention when it is inclined;

FIG. 8 is an enlarged view of the structure of FIG. 4 at B according to the present invention;

FIG. 9 is a view of the mounting structure of one embodiment of the mounting shaft and positive plate of the present invention;

FIG. 10 is a view showing the construction of the mounting shaft and the mounting structure of another embodiment of the positive plate of the present invention;

fig. 11 is a front view of the chute of the present invention.

In the figure: 1. a dust removal pipeline; 2. a material cup; 3. a high temperature resistant gate plate; 4. a feed inlet; 5. a heating chamber; 6. a shutter plate; 7. vibrating the base plate; 8. a chute; 9. a support frame; 10. a refining furnace; 11. a dust remover; 110. a sloping plate; 111. a gas port; 112. a first spring; 115. a positive conductive plate; 116. a support block; 12. installing a shaft; 121. a positive plate; 122. a first spring; 123. an insulating ceramic sheet; 124. bolt holes; 125. a splint; 126. a chute; 127. a second spring; 13. and a negative plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1-11, the embodiment provides a waste heat recycling refining furnace scrap preheating device, which includes a heating bin 5, a chute 8 is installed at the bottom of the heating bin 5, and the chute 8 is in a tubular structure or a rectangular structure and is made of heat-resistant and wear-resistant materials.

As shown in fig. 1 and 2, a refining furnace 10 is connected to the bottom of the chute 8, and the chute 8 is used for sliding off the steel scraps and feeding the steel scraps into the refining furnace 10; and the chute 8 can also lead out flue gas, so that waste gas generated in the refining furnace 10 enters the heating bin 5, and the effect of heating the steel scrap in the heating bin 5 is achieved.

The high-temperature flue gas that is drawn forth in 5 in the heating bunker is fully wrapped up by the refining furnace, and the refining furnace produces 1500 ℃ high-temperature flue gas, and to wearing with the scrap steel and carrying out the heat exchange, refining furnace high-temperature flue gas has a afterburning process at the heating bunker, and the heating bunker has acted as the function of postcombustion room, and the carbon monoxide gas that produces in the smelting process burns at the heating bunker and turns into carbon dioxide and secondary large amount of heat energy that produce. The air is purified, simultaneously, the heating of the scrap steel is realized, and the energy recycling is well realized.

High-temperature flue gas exhausted by the refining furnace is utilized to directly penetrate through and bake the steel scrap in the heating bin 5, waste heat is recycled, energy is saved, consumption is reduced, operating cost is extremely low, and environmental protection effect is good.

The upper end of the heating bin 5 is provided with a dust removal pipeline 1, the tail end of the dust removal pipeline 1 is connected with a dust remover 11, and the dust removal pipeline 1 introduces flue gas into the dust remover 11. The dust collector 11 is a commonly used electrostatic dust collector.

The bottom of the heating chamber 5 is provided with a vibrating bottom plate 7.

In this embodiment, heated warehouses 5's bottom is the rectangle structure, and heated warehouses 5 and vibration bottom plate 7 adopt heat-resisting wear-resisting material, are equipped with the heat preservation, generally set up the heat preservation in the outside, and the heat preservation can adopt evacuation structure's double shell, utilizes the vacuum to reduce calorific loss, realizes the heat preservation to heated warehouses 5, reduces thermal loss, improves the heating effect to the scrap steel.

In order to utilize the heat energy in the waste gas, a dust removal flue connected with the furnace body is transformed into a heating bin, and the waste gas and the scrap steel flow in the reverse direction in the heating bin to heat the scrap steel. The main advantages are that the adding of steel scrap is irrelevant to the melting process, most of the steel scrap is added through the heating bin, the furnace cover does not need to be opened, and the adding direction of the steel scrap is opposite to the waste gas. In addition, the scrap steel is used as an initial filter of the waste gas, most of dust can be collected, and the dust can be cleaned.

A flashboard 6 with holes is arranged between the chute 8 and the heating bin 5, and the flashboard 6 is also made of high-temperature-resistant materials and used for storing and discharging materials and enabling smoke to pass through;

the upper end of one side of the heating bin 5 is provided with a feed inlet 4 for adding the scrap steel. And a high-temperature-resistant flashboard 3 is arranged at the feeding opening 4, and the side opening of the heating bin 5 is blocked after the scrap steel is added, so that cold air is prevented from entering the heating bin 5.

Still including setting up the support frame 9 in heating chamber 5 outside, heating chamber 5 is fixed on support frame 9.

Example 2

Referring to fig. 2, in a further embodiment, the device further comprises a material cup 2 for loading, the material cup 2 has an automatic opening function, a traveling crane is arranged at the upper end of the material cup 2, the traveling crane has a weighing function, and the lifting system is consistent with an existing lifting system.

When the device is used, the required amount of scrap steel is loaded into the material cup 2 and is hung onto the charging opening 4 by the traveling crane, and the traveling crane can also weigh.

At the moment, the flashboard 3 is opened, the flashboard 6 is closed, the scrap steel enters the heating bin 5 through the charging hole 4, then the flashboard 3 is closed, and the scrap steel is fully wrapped by high-temperature flue gas led out from the refining furnace in the heating bin 5.

The refining furnace produces 1500 ℃ of high temperature flue gas, and is worn with the scrap steel and carries out the heat exchange, and refining furnace high temperature flue gas has a afterburning process at the heated warehouses, and the heated warehouses has served as the function of afterburning room, and the carbon monoxide gas that produces in the smelting process burns in the heated warehouses and turns into carbon dioxide and secondary large amount of heat energy of production.

Convection heat transfer and radiation heat transfer exist in the heat exchange process in the heating bin, the convection heat transfer and the radiation heat transfer are heat transfer processes in which heat convection and heat conduction participate at the same time, and the waste steel at the normal temperature is preheated to be more than 800 ℃ after about 25 minutes.

The shutter 6 is then opened and scrap is added to the finer through chute 8. And the cooled waste gas after heat exchange enters an upper dust removal pipeline. After the continuous smelting of the refining furnace reaches the tapping standard, the refining furnace is pulled out by a ladle car and then is hoisted to a revolving platform of a continuous casting machine to enter the working procedure of casting and drawing steel billets.

In a further embodiment, the dust in the electric field is negatively charged under the action of the electric field and moves towards the positive plate when passing through the electric field, so that the replacement frequency of the positive plate is relatively high, and the replacement and cleaning of the positive plate inside the dust collector are facilitated. Referring to fig. 3-4, an air port 111 connected to the dust removal pipe 1 is formed at the upper end of the dust remover 11, a negative plate 13 is installed at one side of an inner cavity of the dust remover 11, an installation shaft 12 for installing the positive plate 121 is rotatably installed at the other side of the dust remover 11, 4 positive plates 121 are installed outside the installation shaft 12, and a dust removal electric field is formed between the positive plates 121 and the negative plate 13. When passing through the electric field, the dust is negatively charged by the electric field, and thus moves toward the positive electrode plate 121 and is adsorbed to the positive electrode plate 121.

Referring to fig. 4-5, the top of the inner cavity of the dust collector 11 is rotatably provided with a positive conductive plate 115, and one side of the positive conductive plate 115 is provided with a first spring 112.

As shown in fig. 5 to 6, positive electrode conductive plate 115 is in a vertical state during operation, and positive electrode plate 121 corresponding to negative electrode plate 13 is in contact with positive electrode conductive plate 115, and first spring causes positive electrode plate 121 to be in close contact with positive electrode conductive plate 115, and positive electrode plate 121 forms a dust removing electric field together with negative electrode plate 13.

The first spring 112 may provide a tensile force or an elastic force to the positive conductive plate 115, as shown in fig. 5 to 6, so long as the positive conductive plate 115 is closely attached to the positive electrode plate 121.

In order to improve the contact effect between the positive conductive plate 115 and the positive plate 121, the support block 116 is fixedly attached to the positive conductive plate 115 on the side directly above the mounting shaft 12, so that the rotation angle of the positive conductive plate 115 can be limited. The maximum rotation angle of the positive electrode conductive plate 115 is a position where the positive electrode conductive plate 115 and the positive electrode plate 121 are just in contact during rotation. The positive plate 121 can be ensured to shift the positive conductive plate 115 to a vertical state in the rotating process of the mounting shaft 12.

In order to ensure the safety of the positive conductive plate 115, referring to fig. 4 to 7, both sides of the positive conductive plate 115 are provided with insulating ceramics, and the insulating ceramics on the side contacting with the positive plate 121 does not extend to the bottom of the positive conductive plate 115 than the positive electrode, so that a right-angle step is formed between the insulating ceramics on the side and the positive conductive plate 115, and when the positive plate 121 pushes the positive conductive plate 115 to a vertical state, the positive plate 121 is just clamped into the step, so that the positive plate 121 contacts with the positive conductive plate 115. And a snap-fit of positive plate 121 into the step may be used to confirm that positive plate 121 has contacted positive conductive plate 115.

As shown in fig. 4, the side of the duster 11 where the mounting shaft 12 is provided with an openable door panel; an opening is arranged on one side of the dust remover 11, and the side wall of the door plate is rotatably connected with the opening. The door panel can be opened to clean the positive plate 121.

And an insulating ceramic piece 123 is arranged between the adjacent positive plates 121, so that the adjacent positive plates 121 are spaced, and the independent work between each positive plate 121 is ensured without mutual influence. When the positive plate 121 is cleaned, the cleaning is safer.

In this embodiment, the outer side of the mounting shaft 12 is fixedly mounted with a mounting frame, the mounting frame is used for mounting the positive plate 121, and the frame structure is intentionally attached to the positive plate 121 more tightly, so as to facilitate the mounting of the positive plate 121.

The one end that installation axle 12 is located the dust remover 11 outside is provided with the handle, and the handle is used for rotating installation axle 12 to move the positive plate and rotate.

In this embodiment, referring to fig. 9, bolt holes 124 are formed in both positive plate 121 and the mounting frame, and positive plate 121 is mounted together with the mounting frame by using bolts.

In addition to the above, the positive electrode plate 121 may be fixed by clamping. Such as: as shown in fig. 10-11, the clamping plates 125 are mounted on both sides of the mounting surface of the mounting frame, wherein the clamping plate on one side is fixedly connected with the mounting frame, and the clamping plate 125 on the other side is slidably mounted with the mounting frame.

A sliding groove 126 is formed in one side of the mounting frame, and a sliding block capable of sliding in the sliding groove 126 is fixedly mounted at the bottom of the clamping plate 125 on one side.

A second spring 127 providing a pulling force to the slider is arranged between the slider and the sliding groove 126, and the second spring 127 provides a pulling force to the sliding clamping plate 125, so that the clamping plate 125 has a better fixing effect on the alignment plate 121.

When placing positive plate 121, support fixed splint 125 with one side of positive plate 121, then press positive plate 121 inwards, can install positive plate 121, compare with the bolt installation, this kind of mounting means is more convenient.

The sliding groove 126 and the sliding block are preferably of T-shaped structures, and can be mutually clamped and cannot fall off.

In order to ensure the effect of the dust collector 11, as shown in fig. 8, a rotatable inclined plate 110 is further disposed at the bottom of the dust collector 11, and a rotating shaft is disposed between the bottom of the inclined plate 110 and the bottom of the dust collector. And the inclined plate 110 is always in an inclined state, and the positive plate 121 at the bottom of the top mounting shaft 12 is contacted, so that the bottom of the mounting shaft 12 and the bottom of the dust remover 11 are in a relatively sealed state, and the air tightness of the box body 1 can be ensured. And one side of the sloping plate 110 is provided with a third spring, and the third spring provides a force for the sloping plate 10, so that the sloping plate 110 is directly and closely contacted with the positive plate 121 at the bottom of the mounting shaft 12, the tightness of the dust remover 11 is improved, and gas leakage from a door plate is prevented.

One side of the swash plate 110 is provided with a stopper such that the swash plate is always in an inclined state, as shown in fig. 8.

When positive plate 121 is changed to needs, only need through rotating the handle, take installation axle 12 to rotate, installation axle 12 takes positive plate 121 to rotate at the pivoted in-process to realize different positive plate 121 and anodal conductive plate 115 contact, realize the position conversion to positive plate 121. And when positive plate 121 rotated door plant department, can open the door plant and dismantle positive plate 121, whole process is very simple, need not shut down moreover when dismantling the change, can continuous work.

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

Claims (10)

1. The utility model provides a waste heat recovery recycles refining furnace steel scrap preheating device, includes heated warehouses (5), chute (8) are installed to the bottom of heated warehouses (5), and chute (8) are used for the landing steel scrap and draw forth flue gas, its characterized in that: the upper end of the heating bin (5) is provided with a dust removal pipeline (1), the tail end of the dust removal pipeline (1) is connected with a dust remover (11), and the bottom of the heating bin (5) is provided with a vibration bottom plate (7);

a flashboard (6) with a hole is arranged between the chute (8) and the heating bin (5);

a feeding opening (4) is formed in the upper end of one side of the heating bin (5), and a high-temperature-resistant flashboard (3) is arranged at the feeding opening (4);

the heating device also comprises a support frame (9) arranged outside the heating bin (5), and the heating bin (5) is fixed on the support frame (9).

2. The waste heat recovery and reutilization refining furnace waste steel preheating device of claim 1, which is characterized in that: the chute (8) is of a tubular structure or a cuboid structure and is made of heat-resistant and wear-resistant materials.

3. The waste heat recovery and reutilization refining furnace waste steel preheating device of claim 1, which is characterized in that: the heating bin (5) and the vibration bottom plate (7) are made of heat-resistant and wear-resistant materials, and heat-insulating layers are arranged on the outer sides of the heating bin and the vibration bottom plate.

4. The waste heat recovery and reutilization refining furnace waste steel preheating device of claim 1, which is characterized in that: an air port (111) connected with the dust removal pipeline (1) is formed in the upper end of the dust remover (11), a negative plate (13) is installed on one side of an inner cavity of the dust remover (11), and an installation shaft (12) is rotatably arranged on the other side of the dust remover (11);

a plurality of positive plates (121) are arranged on the outer side of the mounting shaft (12);

the top of the inner cavity of the dust remover (11) is rotatably provided with a positive conductive plate (115), one side of the positive conductive plate (115) is provided with a first spring (112), the positive conductive plate (115) is in a vertical state during working and is in contact with a positive plate (121) corresponding to a negative plate (13), the positive plate (121) is tightly contacted with the positive conductive plate (115) through the first spring, and the positive plate (121) and the negative plate (13) form a dust removing electric field together;

one side of the dust remover (11) provided with the mounting shaft (12) is provided with an openable door plate;

and an insulating ceramic plate (123) is arranged between every two adjacent positive plates (121).

5. The waste heat recovery and reutilization refining furnace waste steel preheating device of claim 4, which is characterized in that: the outside fixed mounting of installation axle (12) has the installing frame, the one end that installation axle (12) is located dust remover (11) outside is provided with the handle.

6. The waste heat recovery and reutilization refining furnace waste steel preheating device of claim 5, which is characterized in that: bolt holes (124) are formed in the positive plate (121) and the mounting frame.

7. The waste heat recovery and reutilization refining furnace waste steel preheating device of claim 5, which is characterized in that: clamping plates (125) are mounted on two sides of the mounting surface of the mounting frame, the clamping plate on one side is fixedly connected with the mounting frame, and the clamping plate (125) on the other side is slidably mounted with the mounting frame;

a sliding groove (126) is formed in one side of the mounting frame, and a sliding block capable of sliding in the sliding groove (126) is fixedly mounted at the bottom of the clamping plate (125) on one side;

and a second spring (127) for providing tension for the sliding block is arranged between the sliding block and the sliding groove (126).

8. The utility model provides a waste heat recovery recycles refining furnace steel scrap system of preheating which characterized in that: the method comprises the steps of adopting the preheating device, a refining furnace (10) and a material cup (2) for feeding materials according to claim 1, wherein a traveling crane hanger is arranged at the upper end of the material cup (2), and the traveling crane hanger has a weighing function;

the bottom of the chute (8) is communicated with the furnace cover of the refining furnace (10), and the chute (8) is also used as a flue to lead out flue gas.

9. The waste heat recovery and reutilization refining furnace waste steel preheating system of claim 8, which is characterized in that: the upper end furnace cover of the refining furnace (10) is provided with a hole for installing the chute (8).

10. The preheating method for recycling the waste steel of the refining furnace by waste heat recovery is characterized by comprising the following steps of:

s1, loading required amount of scrap steel into a material cup (2), hanging the scrap steel onto a charging hole (4) by a traveling crane, opening a high-temperature-resistant flashboard (3) at the moment, closing a flashboard (6), and enabling the scrap steel to enter a heating bin (5) through the charging hole (4);

s2, closing the gate plate (3), fully wrapping the waste steel in the heating bin (5) by high-temperature flue gas led out from the refining furnace (10), generating 1500 ℃ high-temperature flue gas by the refining furnace, and carrying out heat exchange with the waste steel in a penetrating manner;

the high-temperature flue gas of the refining furnace is combusted secondarily in the heating bin (5), the heating bin (5) has the function of a secondary combustion chamber, and carbon monoxide gas generated in the smelting process is combusted in the heating bin and converted into carbon dioxide to generate a large amount of heat energy secondarily;

s3, the scrap steel is used as an initial filter of the waste gas, and most of dust can be collected; after about 20-45 minutes, preheating the steel scrap at normal temperature to be above 800 ℃, then opening a flashboard (6), and adding the steel scrap into a refining furnace (10) through a chute (8);

and S4, the cooled waste gas after heat exchange enters an upper dust removal pipeline (1), the refining furnace (10) is continuously smelted to reach a tapping standard, pulled out by a ladle car and then hung to a continuous casting machine rotary table to enter a casting billet drawing process.

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