Steel scrap continuous preheating device and steel scrap continuous preheating method

Abstract

The invention discloses a steel scrap continuous preheating device and a steel scrap continuous preheating method.The steel scrap continuous preheating device comprises a non-resonant steel scrap preheating conveyor and an electric furnace, the steel scrap preheating conveyor comprises a feeding section and a preheating section, the feeding section, the preheating section and the electric furnace are sequentially arranged in the conveying direction, and a vibration exciter is arranged on the steel scrap preheating conveyor; a heat preservation cover is installed on the top of the preheating section, a refractory material layer is arranged in the heat preservation cover, a smoke channel is formed between the refractory material layer and the preheating section, the end, close to the electric furnace, of the smoke channel is a smoke inlet, the end, close to the feeding section, of the smoke channel is a smoke outlet, and the smoke channel is provided with the high smoke inlet and the low smoke outlet. High-temperature flue gas generated by the electric furnace enters the flue gas channel through the flue gas inlet to flow and finally flows out through the flue gas outlet, so that the high-temperature flue gas exchanges heat with waste steel on the preheating section, continuous preheating of the waste steel on the preheating section is achieved, the heat exchange efficiency of the waste steel is high, and meanwhile the preheating temperature of the waste steel is increased.

Description

Technical Field

[0001] The invention relates to the technical field of scrap steel preheating, and in particular to a scrap steel continuous preheating device and a scrap steel continuous preheating method. Background Art

[0002] The main reason why the price of electric furnace steel in my country is relatively low is that the energy consumption of electric furnace steel smelting is high, which affects the competitiveness of the product. As one of the key process equipment, the electric furnace short-process smelting process is bound to receive more and more attention. Among them, the electric furnace production technology represented by energy saving and consumption reduction will also usher in a great development.

[0003] Scrap steel preheating technology is one of the key technologies for energy saving and consumption reduction of electric furnaces. Nowadays, there are two types of scrap steel preheating technologies: shaft type and horizontal continuous preheating type. The shaft type scrap steel preheating technology has good heat exchange effect with scrap steel and high preheating temperature because the equipment is arranged directly above the electric furnace. The flue gas directly enters the shaft preheating area through the bottom of the shaft. However, due to the need for frequent feeding of the shaft, scrap steel is easy to impact the lower finger area and is also easy to cause greater wear on the shaft wall. Therefore, finger failure and shaft leakage are problems that have not been well solved, which affects the further expansion of the application scenarios of this technology. In the horizontal continuous preheating type scrap steel preheating technology, the equipment is arranged on one side of the electric furnace, and the flue gas exchanges heat with the scrap steel in the flue through the horizontal flue. Because the high-temperature flue gas flows in the upper part, it cannot have good contact and heat exchange with the scrap steel in the lower part. The scrap steel preheating temperature is low, resulting in high smelting energy consumption, which also affects the further expansion of the application scenarios of this technology. The researchers have successively proposed methods of moving the shaft side out from above the furnace cover, as well as a method of setting up horizontal continuous preheating in a stepped shape, but the results have not been ideal. Summary of the invention

[0004] The present invention aims to provide a scrap steel continuous preheating device to solve the above-mentioned technical problems.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: a scrap steel continuous preheating device, comprising a non-resonant scrap steel preheating conveyor and an electric furnace, the scrap steel preheating conveyor comprising a loading section and a preheating section, the loading section, the preheating section and the electric furnace are arranged in sequence along the conveying direction, an exciter is arranged on the scrap steel preheating conveyor, the loading section is used to convey the scrap steel to the preheating section, the preheating section is used to convey the continuously preheated scrap steel to the electric furnace, and the exciter is used to realize nonlinear continuous motion of the scrap steel in the preheating section; the top of the preheating section An insulation cover is installed, and a refractory material layer is arranged inside the insulation cover. A flue gas channel is formed between the refractory material layer and the preheating section. The end of the flue gas channel close to the electric furnace is the flue gas inlet, and the end close to the loading section is the flue gas outlet. The flue gas channel has a high smoke inlet and a low smoke outlet. The high-temperature flue gas generated by the electric furnace enters the smoke channel through the smoke inlet and finally flows out through the smoke outlet, so that the high-temperature flue gas exchanges heat with the scrap steel in the preheating section, thereby realizing continuous preheating of the scrap steel in the preheating section.

[0006] Preferably, the trapezoidal smoke passage is a continuous passage with a right-angled trapezoidal longitudinal section, that is, the two inner side walls of the trapezoidal smoke passage are opposite and of equal size, and the inner top wall of the trapezoidal smoke passage is a continuous inclined inner top wall without inflection points.

[0007] Preferably, the flow direction of the high-temperature flue gas in the flue gas channel is non-horizontal.

[0008] Preferably, the flow direction of the high-temperature flue gas is opposite to the conveying direction of the scrap preheating conveyor.

[0009] Preferably, the vibrator includes first, second and third vibrators, the first vibrator is arranged at the conveying front end of the feeding section, the second vibrator is arranged between the feeding section and the preheating section, and the third vibrator is arranged between the preheating section and the electric furnace.

[0010] Preferably, the second vibrator is a multifunctional vibrator, and its vibration direction has an X direction parallel to the scrap steel conveying direction and a Y direction perpendicular to the scrap steel conveying direction, so that the curve of the scrap steel movement path is a non-horizontal continuous curve.

[0011] Preferably, a smoke exhaust channel and a dynamic sealing mechanism are also provided on the preheating section, a smoke exhaust fan is installed inside the smoke exhaust channel, and the dynamic sealing mechanism is used to movably seal the smoke exhaust channel.

[0012] Preferably, it also includes a magnetic loading tray, and the scrap steel is adsorbed by the magnetic loading tray and put into the loading section.

[0013] The present invention also provides a method for continuous preheating of scrap steel, comprising any of the above-mentioned continuous preheating devices for scrap steel, comprising the following steps:

[0014] S1. Start the scrap steel preheating conveyor, vibrator and electric furnace;

[0015] S2. The scrap steel is fed into the feeding section, and the scrap steel is transported to the preheating section through the feeding section;

[0016] S3. Under the action of the exciter, the scrap steel makes nonlinear continuous motion in the preheating section. At the same time, the high-temperature flue gas generated by the electric furnace flows into the flue gas channel through the flue gas inlet and finally flows out through the flue gas outlet, so that the high-temperature flue gas exchanges heat with the scrap steel in the preheating section, thereby realizing continuous preheating of the scrap steel in the preheating section. Finally, the preheating section transports the continuously preheated scrap steel to the electric furnace.

[0017] Preferably, the vibration exciter maintains nonlinear continuous vibration, and the nonlinear continuous vibration includes sinusoidal continuous vibration, or non-sinusoidal continuous vibration, or parabolic continuous vibration.

[0018] The present invention has the following beneficial effects:

[0019] The present invention enables the scrap steel to move in the horizontal X direction and the vertical Y direction during the transportation process through the action of the vibrator, that is, the movement path of the scrap steel presents a non-horizontal continuous motion curve, and the scrap steel moving up and down easily generates a porous channel, which is conducive to the entry of high-temperature flue gas. At the same time, combined with the structural setting of the high flue gas inlet and low flue gas outlet of the flue gas channel, the non-horizontal movement of the high-temperature flue gas can be achieved, which is conducive to the contact of the flue gas with the surface of the scrap steel and the entry of the porous channel inside the scrap steel, thereby improving the heat exchange efficiency and the preheating temperature of the scrap steel. According to experimental tests, the preheating method of the present invention can increase the preheating temperature of the scrap steel by 100-200 degrees, reduce the smelting power consumption by 20-40kWh / t steel, shorten the smelting time by 1-2min, reduce the cost of producing a ton of steel, be more economical and practical, and enhance the competitiveness of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of the structure of the smoke channel of the embodiment of the present invention.

[0022] The accompanying drawings are marked with: 1 loading section, 2 preheating section, 3 electric furnace, 4 heat preservation cover, 5 smoke channel, 51 smoke inlet, 52 smoke outlet, 6 smoke exhaust channel, 7 dynamic sealing mechanism, 8 first vibrator, 9 second vibrator, 10 third vibrator, 11 magnetic loading tray. DETAILED DESCRIPTION

[0023] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0024] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] See also Figure 1 and 2 As shown, as an embodiment of the present invention, a scrap steel continuous preheating device is provided, including a non-resonant scrap steel preheating conveyor and an electric furnace 3, the scrap steel preheating conveyor includes a loading section 1 and a preheating section 2, the loading section 1, the preheating section 2, and the electric furnace 3 are arranged in sequence along the conveying direction, and an exciter is arranged on the scrap steel preheating conveyor, the loading section 1 is used to convey the scrap steel to the preheating section 2, the preheating section 2 is used to convey the continuously preheated scrap steel to the electric furnace 3, and the exciter is used to realize nonlinear continuous motion of the scrap steel on the preheating section 2; a heat preservation cover 4 is installed on the top of the preheating section 2, A refractory material layer is provided inside the heat preservation cover 4, and a flue gas channel 5 is formed between the refractory material layer and the preheating section 2. The end of the flue gas channel 5 close to the electric furnace 3 is a flue gas inlet 51, and the end close to the feeding section 1 is a flue gas outlet 52. The flue gas channel 5 is a flue gas channel 5 with a high smoke inlet 51 and a low smoke outlet 52. The high-temperature flue gas generated by the electric furnace 3 enters the smoke channel 5 through the smoke inlet 51 and finally flows out through the smoke outlet 52, so that the high-temperature flue gas exchanges heat with the scrap steel in the preheating section 2, thereby realizing continuous preheating of the scrap steel in the preheating section 2.

[0027] The present invention enables the scrap steel to move in the horizontal X direction and the vertical Y direction during the transportation process through the action of the vibrator, that is, the movement path of the scrap steel presents a non-horizontal continuous motion curve, and the scrap steel moving up and down easily generates pore channels, which is conducive to the entry of high-temperature flue gas, thereby improving the heat exchange efficiency and the preheating temperature of the scrap steel; and the high smoke inlet 51 and low smoke outlet 52 of the smoke channel 5 can realize the non-horizontal movement of the high-temperature flue gas, which is conducive to the contact of the flue gas with the surface of the scrap steel and the entry into the pore channels inside the scrap steel, further improving the heat exchange efficiency and the preheating temperature of the scrap steel. According to experimental tests, the preheating method of the present invention can increase the preheating temperature of the scrap steel by 100-200 degrees, reduce the smelting power consumption by 20-40kWh / t steel, shorten the smelting time by 1-2min, reduce the cost of producing a ton of steel, be more economical and practical, and enhance the competitiveness of enterprises.

[0028] In this embodiment, the flow direction of the high-temperature flue gas in the flue gas channel 5 is non-horizontal, and the flow direction of the high-temperature flue gas is opposite to the conveying direction of the scrap steel preheating conveyor. The trapezoidal flue gas channel 5 is a continuous channel with a right-angled trapezoidal longitudinal section, that is, the two inner side walls of the trapezoidal flue gas channel 5 are opposite and equal in size, and the inner top wall of the trapezoidal flue gas channel 5 is a continuous inclined inner top wall without inflection points. This arrangement allows the high-temperature flue gas to move relative to the scrap steel and impact the scrap steel downward to achieve efficient heat exchange.

[0029] Of course, in other cases, it is also possible for the inner top wall of the smoke channel 5 to be a parabola.

[0030] In this embodiment, a smoke exhaust channel 6 and a dynamic sealing mechanism 7 are also provided on the preheating section 2. A smoke exhaust fan is installed inside the smoke exhaust channel 6. The dynamic sealing mechanism 7 is used to flexibly seal the smoke exhaust channel 6. The exciter includes a first, a second, and a third exciter 10. The first exciter 8 is arranged at the conveying front end of the feeding section 1, the second exciter 9 is arranged between the feeding section 1 and the preheating section 2, and the third exciter 10 is arranged between the preheating section 2 and the electric furnace 3, so as to ensure that the scrap steel can stably and continuously perform nonlinear motion during transportation. Among them, the second exciter 9 is a multifunctional exciter, and its vibration direction has an X direction parallel to the scrap steel conveying direction and a Y direction perpendicular to the scrap steel conveying direction, so that the curve of the movement path of the scrap steel is a non-horizontal continuous curve. The present invention is through a multifunctional exciter arranged at a position close to the dynamic sealing outlet, and through a trapezoidal smoke channel 5 with a high smoke inlet 51 and a low smoke outlet 52. The combination of the two, on the one hand, enables the scrap steel on the preheating section 2 to reciprocate up and down and left and right in the vertical plane, and on the other hand, enables the high-temperature flue gas to impact the scrap steel surface at an angle and enter the pores that appear during the up and down movement of the scrap steel, and the high-temperature flue gas penetrates into the scrap steel on the preheating section 2 for preheating. Through the combined effect of these two structures, the preheating temperature of the scrap steel on the preheating section 2 can be greatly increased, the smelting power consumption can be reduced, the smelting time can be shortened, and the market competitiveness of the steel in the electric furnace 3 can be improved.

[0031] In this embodiment, a magnetic loading tray 11 is further included, and the scrap steel is adsorbed by the magnetic loading tray 11 and put into the loading section 1 to ensure the stability of loading.

[0032] The present invention also provides a method for continuous preheating of scrap steel, comprising the following steps:

[0033] S1. Start the scrap preheating conveyor and the electric furnace 3 to work;

[0034] S2. The scrap steel is fed into the feeding section 1, and the scrap steel is transported to the preheating section 2 through the feeding section 1;

[0035] S3. Under the action of the exciter, the scrap steel makes nonlinear continuous motion in the preheating section 2. At the same time, the high-temperature flue gas generated by the electric furnace 3 enters the flue gas channel 5 through the flue gas inlet 51 and finally flows out through the flue gas outlet 52, so that the high-temperature flue gas exchanges heat with the scrap steel in the preheating section 2, thereby realizing continuous preheating of the scrap steel in the preheating section 2. Finally, the preheating section 2 transports the continuously preheated scrap steel to the electric furnace 3.

[0036] The preheating method solves the problem that in the current short-process production process of electric furnaces, the preheated scrap steel temperature is low, the smelting power consumption is high, and the market competitiveness of electric furnace 3 steel is weak because the scrap steel and high-temperature flue gas cannot be efficiently exchanged. The method sets a non-resonant scrap steel preheating conveyor, configures an exciter as needed, and sets a multifunctional exciter at the front end of the preheating section 2, so that the scrap steel can be reciprocated up and down in the vertical plane of the conveying direction, which will cause the scrap steel in the preheater to be continuously transported to the outlet direction during the up and down reciprocating movement. The high-temperature flue gas passes through a trapezoidal channel with a high flue gas inlet 51 and a low flue gas outlet 52, forcing the high-temperature flue gas to impact the scrap steel in the opposite direction at a certain angle, so that the high-temperature flue gas can enter the interior of the scrap steel, thereby completing efficient heat exchange. Through the non-resonant four-directional movement of the scrap steel on the preheating section 2 and the forced convection heat exchange effect of the high-temperature flue gas, the scrap steel preheating temperature can be greatly increased, the smelting power consumption can be reduced, the smelting time can be shortened, and the market competitiveness of electric furnace steel can be improved.

[0037] The exciter in this method needs to maintain nonlinear continuous vibration, which includes sinusoidal continuous vibration, non-sinusoidal continuous vibration, parabolic continuous vibration and other modes.

[0038] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes in form and details made to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims will fall within the scope of protection of the present invention.

Claims

1. A scrap steel continuous preheating device, characterized in that: The invention comprises a non-resonant scrap steel preheating conveyor and an electric furnace. The scrap steel preheating conveyor comprises a loading section and a preheating section. The loading section, the preheating section and the electric furnace are arranged in sequence along the conveying direction. The scrap steel preheating conveyor is provided with an exciter. The loading section is used to convey the scrap steel to the preheating section. The preheating section is used to convey the scrap steel after continuous preheating to the electric furnace. The exciter is used to realize nonlinear continuous motion of the scrap steel in the preheating section. A heat preservation cover is installed on the top of the preheating section. A refractory material layer is arranged inside the heat preservation cover. A flue gas channel is formed between the refractory material layer and the preheating section. The end of the flue gas channel close to the electric furnace is a flue gas inlet, and the end close to the loading section is a flue gas outlet. The flue gas channel has a high smoke inlet and a low smoke outlet. The high-temperature flue gas generated by the electric furnace enters the smoke channel through the smoke inlet and finally flows out through the smoke outlet, so that the high-temperature flue gas exchanges heat with the scrap steel in the preheating section, thereby realizing continuous preheating of the scrap steel in the preheating section.

2. The scrap steel continuous preheating device according to claim 1, characterized in that: The trapezoidal smoke passage is a continuous passage with a right-angled trapezoidal longitudinal section, that is, the two inner side walls of the trapezoidal smoke passage are opposite and of equal size, and the inner top wall of the trapezoidal smoke passage is a continuous inclined inner top wall without inflection points.

3. The scrap steel continuous preheating device according to claim 1, characterized in that: The flow direction of the high-temperature flue gas in the flue gas channel is non-horizontal.

4. The scrap steel continuous preheating device according to claim 1, characterized in that: The flow direction of the high-temperature flue gas is opposite to the conveying direction of the scrap preheating conveyor.

5. The continuous preheating device for scrap steel according to claim 1, characterized in that: The vibrator includes first, second and third vibrators. The first vibrator is arranged at the conveying front end of the feeding section, the second vibrator is arranged between the feeding section and the preheating section, and the third vibrator is arranged between the preheating section and the electric furnace.

6. The scrap steel continuous preheating device according to claim 5, characterized in that: The second vibrator is a multifunctional vibrator, and its vibration direction has an X direction parallel to the scrap steel conveying direction and a Y direction perpendicular to the scrap steel conveying direction, so that the curve of the scrap steel movement path is a non-horizontal continuous curve.

7. The continuous preheating device for scrap steel according to claim 1, characterized in that: The preheating section is also provided with a smoke exhaust channel and a dynamic sealing mechanism. A smoke exhaust fan is installed inside the smoke exhaust channel. The dynamic sealing mechanism is used to flexibly seal the smoke exhaust channel.

8. The scrap steel continuous preheating device according to claim 1, characterized in that: It also includes a magnetic loading tray, through which the scrap steel is adsorbed and put into the loading section.

9. A method for continuous preheating of scrap steel, characterized in that: The scrap steel continuous preheating device according to any one of claims 1 to 8 comprises the following steps: S1. Start the scrap steel preheating conveyor, vibrator and electric furnace; S2. The scrap steel is fed into the feeding section, and the scrap steel is transported to the preheating section through the feeding section; S3. Under the action of the exciter, the scrap steel makes nonlinear continuous motion in the preheating section. At the same time, the high-temperature flue gas generated by the electric furnace flows into the flue gas channel through the flue gas inlet and finally flows out through the flue gas outlet, so that the high-temperature flue gas exchanges heat with the scrap steel in the preheating section, thereby realizing continuous preheating of the scrap steel in the preheating section. Finally, the preheating section transports the continuously preheated scrap steel to the electric furnace.

10. The method for continuous preheating of scrap steel according to claim 9, characterized in that: The exciter maintains nonlinear continuous vibration, and the nonlinear continuous vibration includes sinusoidal continuous vibration, or non-sinusoidal continuous vibration, or parabolic continuous vibration.

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