Scrap steel preheating system

Abstract

The utility model discloses a waste steel preheating system. The system comprises a charging trough, a heating trough, a soaking trough and a discharging mechanism which are sequentially connected in series. A heating cover and a soaking cover are arranged above the heating trough and the soaking trough in a covering mode, burners are arranged in the heating cover and the soaking cover, a heating side air draft channel is arranged at the bottom of the heating trough, and a soaking side air draft channel is arranged at the bottom of the soaking trough. By arranging the heating side air draft channel and the soaking side air draft channel with different side air draft depths, the flowability of high-temperature flue gas from top to bottom is enhanced, the preheating efficiency and effect of waste steel are improved, meanwhile, the energy utilization efficiency is improved, the energy consumption is reduced, and the preheating uniformity of the waste steel is improved; the device has the advantages of simple structure, low investment cost, low energy consumption, high production efficiency and the like.

Description

Technical Field

[0001] The utility model relates to steel production and processing equipment, in particular to a scrap steel preheating system, and belongs to the technical field of steel production and processing. Background Art

[0002] The steel industry is the second largest carbon emission industry in my country. Reducing energy consumption per ton of steel and recycling scrap steel resources are key measures for steel to achieve the "dual carbon" strategy. According to statistics, every ton of scrap steel used as a raw material substitute can save 1.7 tons of iron ore concentrate and reduce the mining of 4.25 tons of primary ore. Scrap steel is a recyclable resource with a normal cycle of 8 to 30 years and can be recycled indefinitely. Compared with iron ore, using scrap steel to make the same amount of steel can save 60% energy and 40% water, and reduce emissions of waste gas by 86%, waste water by 76%, and waste slag by 97%. At present, my country's scrap steel ratio (the proportion of scrap steel used in steelmaking in the steel industry as raw materials) is around 20%, which is a big gap from the goal of 30% scrap steel ratio proposed by the Ministry of Industry and Information Technology by 2025. There are two main reasons for the relatively low scrap steel in my country. On the one hand, the domestic scrap steel reserves are still in a period of rapid growth, the supporting industrial chain is not yet perfect, and the recycling of scrap steel resources is difficult to fully realize; on the other hand, due to process limitations, the preheating temperature of scrap steel in the steelmaking process is limited. Forcibly increasing the scrap steel ratio can easily lead to large cold areas in the furnace molten pool, which can lead to an exponential increase in energy consumption and affect smooth production. In severe cases, the entire furnace molten steel condenses and cannot flow, causing serious production accidents. It can be seen from this that increasing the temperature and sensible heat of scrap steel and reducing its adverse effects on the original process after entering the furnace are the key to achieving a technical breakthrough.

[0003] During the steelmaking process of the short-process electric arc furnace, high-temperature flue gas exceeding 1000°C will be generated. While the scrap steel is being transported to the electric furnace, the hot flue gas generated by the electric furnace is used to preheat the scrap steel. No external energy medium is required, which is a typical waste heat recovery method. Most of this method is implemented through horizontal Consteel equipment and vertical shaft equipment. In the horizontal Consteel channel, the scrap steel is below the trough and the flue gas flows in reverse above the channel. The heat exchange between the scrap steel and the flue gas mainly relies on radiation heat exchange, which has low heat exchange efficiency and the preheating temperature of the scrap steel is often below 500°C. In the vertical shaft preheating method, the scrap steel and the flue gas can realize convection heat exchange, and the preheating temperature is higher than that of the horizontal preheating. However, the problem of equipment forward movement caused by the finger bonding at the bottom of the shaft has greatly limited the development of the vertical shaft preheating. In addition, the above preheating method can only be used for short-process electric furnace steelmaking, and cannot be achieved for long-process steelmaking.

[0004] The use of ladle roaster to preheat scrap steel is to put the scrap steel into the ladle or scrap steel hopper, place it under the ladle roaster burner for preheating, and then pour the preheated scrap steel into the converter for smelting, or the ladle roaster carries the hot scrap steel to the converter / electric furnace to receive molten steel; this preheating method is simple and convenient, but the amount of scrap steel added to the ladle is limited, and the hot flue gas is difficult to reach the scrap steel at the bottom of the ladle, so the preheating effect is not good. In addition, the flame is prone to rebound to the outside of the ladle after impacting the scrap steel surface, resulting in energy waste.

[0005] An independent heating furnace is used to heat the scrap steel. The furnace is supplemented with heat through coal gas or natural gas burners. The high-temperature flue gas generated by fuel combustion heats the scrap steel in the furnace. After heating, the scrap steel is added to the subsequent iron ladle, steel ladle or converter. This method can flexibly control the amount of preheated scrap steel, but it also has problems such as slow heating speed, low preheating temperature, only heating the surface of the scrap steel, and difficulty in accurate and stable material feeding. Utility Model Content

[0006] In view of the problems of low preheating efficiency, poor preheating effect, high energy consumption, etc. in the prior art for heating scrap steel, the utility model provides a scrap steel preheating system. By arranging a heating side exhaust duct and a heat-averaging side exhaust duct at the bottom of the heating trough and the heat-averaging trough, the fluidity of the high-temperature flue gas from top to bottom is enhanced, and while improving the preheating efficiency and effect of the scrap steel, the energy utilization efficiency is improved and the energy consumption is reduced; in addition, by arranging the heating side exhaust duct and the heat-averaging side exhaust duct with different side exhaust depths, the uniformity of the scrap steel preheating is further improved.

[0007] In order to achieve the above technical objectives, the technical solutions adopted by the present utility model are specifically described as follows:

[0008] A scrap steel preheating system, the system comprises a feeding trough, a heating trough, a heat equalizing trough and a discharge mechanism connected in series in sequence. The feeding trough, the heating trough and the heat equalizing trough are all U-shaped trough structures with an open upper end. A heating hood is provided above the heating trough, and a heating burner is provided in the heating hood, and a heating side exhaust duct is provided at the bottom of the heating trough. A heat equalizing hood is provided above the heat equalizing trough, and a heat equalizing burner is provided in the heat equalizing hood, and a heat equalizing side exhaust duct is provided at the bottom of the heat equalizing trough. A vibration horizontal feeding drive device is also provided at the front end of the feeding trough, and the material is driven by the vibration horizontal feeding drive device to flow through the feeding trough, the heating trough and the heat equalizing trough in sequence and then discharged from the discharge mechanism.

[0009] Preferably, the heating burner and the equalizing burner are both connected with a gas pipeline and a combustion-supporting air duct, and the combustion-supporting air duct is provided with a combustion-supporting fan. The air outlet of the equalizing hood is connected with the main exhaust fan through the main flue gas exhaust duct.

[0010] Preferably, a heating side exhaust duct extending along the width direction (referring to the direction perpendicular to the material running in the horizontal plane) of the bottom wall surface of the heating trough is provided on both sides. The air inlet ends of the two heating side exhaust ducts extend toward each other along the bottom surface of the heating trough and approach the middle of the bottom surface of the heating trough, and their other ends respectively penetrate the side walls of the heating trough and extend to the outside. A first horizontal spacing is left between the air inlet ends of the two heating side exhaust ducts.

[0011] Preferably, the heating side exhaust duct located on either side of the bottom of the heating trough includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heating trough (referring to the direction of material movement in the horizontal plane), or the heating side exhaust duct located on either side of the bottom of the heating trough is a flat exhaust cavity extending along the length direction of the heating trough. The air outlets of the heating side exhaust ducts are connected to the air inlet end of the main flue gas discharge duct through the side exhaust air duct and the side exhaust fan. Preferably, the side exhaust air duct is connected to the air outlet of the heating side exhaust duct through a dynamic and static connecting hose, and a heating flue gas temperature detector is provided in the dynamic and static connecting hose.

[0012] Preferably, the heating hood is an arc-shaped structure, and a pair of heating burners are arranged on the hood body located on both sides of the arc top of the heating hood. Preferably, in the length direction of the heating trough, the heating hood is provided with multiple pairs of symmetrically arranged heating burners.

[0013] Preferably, the heat hood is an arc-shaped structure, and a heat burner is arranged on the hood body located at the top of the heat hood. Preferably, a plurality of heat burners are arranged on the heat hood in the length direction of the heat trough. The heat hood extends backward and is arranged on the feed port of the discharge mechanism.

[0014] Preferably, the angle formed between the axis of the heating burner and the horizontal plane is α (the angle here refers to an acute angle), wherein 10°≤α≤80°, preferably 30°≤α≤60°.

[0015] Preferably, the first horizontal spacing (referring to the horizontal spacing along the width direction) is D 1 , and there is: k·D 1 <2(R 1 -L 1 )cosα. Where: R 1 is the arc radius of the heating hood, L 1 is the flame length of the heating burner, k is the correction factor and 1.5≤k≤2.

[0016] Preferably, a heat-equalizing side exhaust duct extending along the width direction is provided on each of the two sides of the bottom wall surface of the heat-equalizing material tank. The air inlet ends of the two heat-equalizing side exhaust ducts extend toward each other along the bottom surface of the heat-equalizing material tank and approach the middle of the bottom surface of the heat-equalizing material tank, and the other ends thereof penetrate the two side walls of the heat-equalizing material tank and extend to the outside. A second horizontal spacing is left between the air inlet ends of the two heat-equalizing side exhaust ducts.

[0017] Preferably, the heat-equalizing side exhaust duct located on either side of the bottom of the heat-equalizing trough includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heat-equalizing trough, or the heat-equalizing side exhaust duct located on either side of the bottom of the heat-equalizing trough is a flat exhaust cavity extending along the length direction of the heat-equalizing trough. The air outlet of the heat-equalizing side exhaust duct is connected to the air inlet end of the main flue gas discharge duct through the side exhaust air duct and the side exhaust fan. Preferably, the side exhaust air duct is connected to the air outlet of the heat-equalizing side exhaust duct through a dynamic and static connecting hose, and a heat-equalizing flue gas temperature detector is provided in the dynamic and static connecting hose.

[0018] Preferably, the second horizontal spacing (referring to the horizontal spacing along the width direction) is D 2 , and: 0.75<D 2 / D 3 <0.9. Among them: D 3 is the width of the heat equalizing trough.

[0019] Preferably, an indirect heat exchanger is provided between the main flue gas discharge duct and the combustion-supporting air duct.

[0020] Preferably, a heating air cooling channel is provided inside the trough wall of the heating material trough, and the air inlet and the air outlet of the heating air cooling channel are both provided on the side wall of the heating material trough.

[0021] Preferably, the air inlet and the air outlet of the heating air cooling channel are respectively opened on the left wall and the right wall of the heating trough. That is, the heating air cooling channel is a one-way channel passing through the inside of the left wall of the heating trough, the inside of the bottom wall of the heating trough and the inside of the right wall of the heating trough in sequence.

[0022] Alternatively, the air inlet and the air outlet of the heating air cooling channel are both opened on the left side wall of the heating trough. The heating air cooling channel is a round-trip two-way channel that passes through the inside of the left side wall of the heating trough, the inside of the bottom wall of the heating trough, the inside of the right side wall of the heating trough, the inside of the bottom wall of the heating trough, and the inside of the left side wall of the heating trough in sequence.

[0023] Preferably, the air outlet of the heating air cooling channel is connected to the air inlet of the combustion-supporting fan through a circulating air duct. Preferably, a venting branch pipe and a venting valve are provided on the circulating air duct.

[0024] Preferably, a heat-equalizing air-cooling channel is provided inside the wall of the heat-equalizing material tank, and the air inlet and the air outlet of the heat-equalizing air-cooling channel are both arranged on the side wall of the heat-equalizing material tank.

[0025] Preferably, the air inlet and the air outlet of the heat-averaging air-cooling channel are respectively provided on the left and right walls of the heat-averaging material tank. That is, the heat-averaging air-cooling channel is a one-way channel passing through the left wall of the heat-averaging material tank, the bottom wall of the heat-averaging material tank and the right wall of the heat-averaging material tank in sequence.

[0026] Alternatively, the air inlet and the air outlet of the heat-averaging air-cooling channel are both opened on the left wall of the heat-averaging material tank. The heat-averaging air-cooling channel is a round-trip two-way channel that passes through the left wall of the heat-averaging material tank, the bottom wall of the heat-averaging material tank, the right wall of the heat-averaging material tank, the bottom wall of the heat-averaging material tank, and the left wall of the heat-averaging material tank in sequence.

[0027] Preferably, the air outlet of the heat-averaging air cooling channel is connected to the air inlet of the combustion-supporting fan through a circulating air duct. Preferably, a venting branch pipe and a venting valve are provided on the circulating air duct.

[0028] In the present utility model, it should be noted that the air cooling channels (including heating air cooling channels and equalizing air cooling channels) are evenly distributed inside the trough wall of the material trough (including all trough walls of the heating material trough and the equalizing material trough) in the form of small channels such as S-shaped, Z-shaped, and U-shaped channels. The inside of the trough wall of the material trough can also be hollowed out and divided into one or more large cavities as air cooling channels.

[0029] Preferably, the unloading mechanism includes a dust removal hood and a buffer silo. The buffer silo is arranged below the discharge end of the heat equalizing trough, and the feed port of the buffer silo is connected to the discharge end of the heat equalizing trough, and the dust removal hood is arranged between the feed port of the buffer silo and the discharge end of the heat equalizing trough. The air outlet on the dust removal hood is connected to the main exhaust fan through a pipeline. A discharge valve is arranged at the lower part of the side wall of the buffer silo.

[0030] Preferably, the cache silo is a cone-shaped structure that is wide at the top and narrow at the bottom. Preferably, one side wall of the cache silo is a vertical side wall, and the other side walls are arc-shaped side walls as a whole. Preferably, a weighing meter is also provided on the cache silo.

[0031] Preferably, the discharge valve comprises a discharge gate and a sealing gate, both of which are arranged on the vertical side wall, wherein the sealing gate is located outside the discharge side of the discharge gate and completely covers the discharge gate.

[0032] Preferably, the arc-shaped side wall is a steepest descent curve structure, specifically: taking the bottom end of the vertical side wall of the buffer silo as the origin, the curve formed by the arc-shaped side wall satisfies:

[0033] When γ∈(π,2π), y=D4 ·(γ-sinγ-π),z=H·[(cosγ-1)+2].

[0034] Among them, γ is the intermediate variable; y is the coordinate of the buffer silo in the length direction; z is the coordinate of the buffer silo in the height direction. 4 is the length of the opening at the top of the buffer silo. H is the height of the vertical side wall of the buffer silo. Preferably, D 4 =H.

[0035] In the present invention, "length direction" refers to "the direction in which the material moves in the horizontal plane". "Width direction" refers to "the direction perpendicular to the material moving in the horizontal plane". "Height direction" (also called vertical direction) refers to "the direction perpendicular to the horizontal plane in the horizontal plane".

[0036] Preferably, the system further comprises a negative pressure cover. The negative pressure cover is arranged between the feeding trough and the heating trough and is connected to the heating cover. An axial flow fan is arranged in the negative pressure cover. Pressure sensors are independently arranged in the negative pressure cover and the heating cover, and the pressure sensors are linked to the axial flow fan.

[0037] Preferably, a flattener is provided at the feeding end of the negative pressure hood.

[0038] Preferably, a feeding mechanism is provided above the feeding trough. Preferably, the feeding mechanism is a feeding overhead crane with a magnetic suction cup.

[0039] In the utility model, the scrap steel preheating system includes a feeding section (i.e., a feeding trough), a heating section (i.e., a heating trough), a heat equalizing section (i.e., a heat equalizing trough), and a discharge section (i.e., a discharge mechanism). By providing a heating side exhaust duct at the bottom of the heating trough and a heat equalizing trough at the bottom, that is, by adopting a bottom side exhaust method, a part of the high-temperature flue gas in the heating trough and the heat equalizing trough flows from top to bottom, so that the upper high-temperature hot flue gas can transfer heat to the upper scrap steel by radiation and can also efficiently transfer heat to the bottom and side scrap steel by convection, which greatly improves the preheating efficiency and preheating temperature of the scrap steel, and at the same time improves the overall preheating uniformity of the scrap steel, avoiding the occurrence of local cold zones. Since the contact heat exchange efficiency between the flue gas and the scrap steel is improved, the heat utilization efficiency is greatly improved, thereby significantly reducing energy consumption. It should be noted that the above preheating method can increase the overall preheating temperature of scrap steel to more than 800℃ or even 1000℃. The increase in the preheating temperature of scrap steel has the following benefits for the steelmaking process: First, it helps to increase the amount of scrap steel added. The higher the preheating temperature of scrap steel, the less energy is required for the steelmaking process. Taking converter steelmaking as an example, by preheating scrap steel, the proportion of scrap steel added can be increased from 15% to more than 30%; second, it helps to increase the melting speed of scrap steel and speed up the steelmaking rhythm. The melting of scrap steel with high preheating temperature requires less heat from the outside, so it melts faster during steelmaking, the steelmaking rhythm is faster, and the addition of scrap steel has less impact on the steelmaking rhythm; third, it helps to remove impurities in scrap steel. After raising the scrap steel temperature to 600℃ or even above 800℃, impurities in the scrap steel, such as paint, plastic and other volatile substances, can be removed to prevent them from entering the molten steel and improve the purity of the molten steel.

[0040] In the present invention, the feeding section is composed of one or more open feeding troughs connected in series. The structure of the feeding trough is as follows: Figure 2 As shown, the material of the feeding trough is preferably wear-resistant steel. The feeding trough is an upper opening type (i.e., a U-shaped structure) as a whole. Reinforcement ribs are welded on the inner side wall at a certain distance to prevent the trough body from being deformed due to the extrusion of the scrap steel material. The feeding crane transports the scrap steel to the feeding trough through the magnetic suction cup, and the vibrating horizontal feeding drive device arranged at the front end of the feeding section makes the scrap steel move forward (when the scrap steel needs to be moved forward (from front to back, i.e., Figure 1 When the scrap steel is transported from left to right in the horizontal feeding process, the vibrating horizontal feeding drive device works to transport the scrap steel material forward in a horizontal vibration manner and is flattened when passing through the flattener and enters the rear heating section at a certain height. According to engineering practice, the stacking height of this scrap steel is generally controlled to be around 800-1000mm.

[0041] In the utility model, the heating section is composed of one or more open heating troughs connected in series, and the charging trough is also a U-shaped structure as a whole; different from the charging trough, a heating hood is provided above all the charging troughs, and a heating furnace is formed between the interior of the heating hood and the scrap steel layer; a heating burner is provided inside the furnace, and the gas and combustion-supporting air are transported to the heating burner for combustion, and high-temperature flue gas is generated to heat the scrap steel in the heating trough. Further, in order to improve the uniformity of heating the scrap steel, the heating hood is designed as an arc-shaped structure, and at least one pair of heating burners are symmetrically arranged on the hood body located on both sides of the arc top of the heating hood, and the flame blowing direction of the heating burner is toward the middle of the scrap steel layer in the charging trough (that is, the angle formed between the axis of the heating burner (the central axis along the flame injection direction) and the horizontal plane is α, where 10°≤α≤80°, preferably 30°≤α≤60°), such a design helps the high-temperature flame to flow downward and horizontally toward the flue gas outlet, thereby improving its heating efficiency and effect on the scrap steel.

[0042] In the utility model, a heating side exhaust duct extending along the width direction is provided on each side of the bottom wall surface of the heating trough. The high-temperature flue gas generated by the combustion of gas and compressed air through the gas burner passes through the scrap steel layer from top to bottom and is extracted through the heating side exhaust duct. It should be noted that the air inlet ends of the two heating side exhaust ducts extend toward each other along the bottom surface of the heating trough and are close to the middle of the bottom surface of the heating material, and a first horizontal spacing is left between the air inlet ends of the two heating side exhaust ducts, that is, through the two specially arranged heating side exhaust ducts, the high-temperature flue gas can evenly pass through the scrap steel layer downward, which is helpful to efficiently preheat the scrap steel at the bottom of the material layer, thereby improving the overall preheating efficiency and preheating uniformity of the scrap steel layer. Generally, the first horizontal spacing is D 1 , and there is: k·D 1 <2(R 1 -L 1 )cosα. Where: R 1 is the arc radius of the heating hood 201, L 1 is the flame length of the heating burner 202, k is a correction factor and 1.5≤k≤2. In addition, support columns are evenly arranged at appropriate intervals inside the exhaust duct on the heating side to support the upper part of the duct to prevent deformation.

[0043] In the present invention, the heat equalization section is composed of one or more open heat equalization troughs connected in series, and its structure is similar to that of the feeding trough. A heat equalization hood is provided above the heat equalization trough, except that a heat equalization burner is provided on the hood body located at the arc top of the heat equalization hood. By adding the heat equalization trough and the heat equalization burner, the temperature distribution of the cross section of the heated scrap steel layer is further guaranteed to be uniform. At the same time, a heat equalization side exhaust duct extending along the width direction is provided on both sides of the bottom wall surface of the heat equalization trough, and the air inlet ends of the two heat equalization side exhaust ducts extend toward each other along the bottom surface of the heat equalization trough and close to the middle of the bottom surface of the heat equalization trough. A second horizontal spacing is left between the air inlet ends of the two heat equalization side exhaust ducts, and the second horizontal spacing is D. 2 , and: 0.75<D 2 / D 3 <0.9. Among them: D 3 To equalize the width of the heat trough, the gas and compressed air form a high-temperature flame after passing through the gas burner. The high-temperature flame flows downward and horizontally toward the flue gas outlet to further ensure the uniformity of the scrap steel layer temperature. In addition, support columns are evenly arranged at appropriate intervals inside the exhaust duct on the heat-equalizing side to support the upper part of the duct to prevent deformation.

[0044] In the present invention, the horizontal spacings reserved between the exhaust ducts at the bottom sides of the feeding trough in the heating section and the equalizing trough in the equalizing section are different (i.e., the first horizontal spacing and the second horizontal spacing are different). In addition, the arrangement of the heating burners on the heating hood is different from that of the equalizing burners on the equalizing hood, i.e., the vertical directions of the hot flue gas extracted from the feeding trough and the equalizing trough are different. 1) In order to maximize the flow of scrap steel through which the extracted hot flue gas flows and to ensure that this part of the hot flue gas can heat more scrap steel, when the burners are arranged on both sides of the cross section, the lower exhaust port is set in the middle of the bottom. 1) The scrap steel in the middle needs to pass through the scrap steel-feeding troughs on both sides to dissipate heat outwards, and the heat dissipation thermal resistance is large. Therefore, the insulation of the scrap steel on both sides is the key point. Therefore, in the equalizing section, the flue gas should pass through the scrap steel on both sides at the bottom as much as possible. For the scrap steel above the bottom, they are closer to the gas burner and can obtain enough radiant heat from the flue gas to achieve the purpose of insulation.

[0045] In the present utility model, in order to further reduce heat loss and energy consumption, air cooling channels (heating air cooling channels and heat equalizing air cooling channels, for the sake of convenience of description, hereinafter collectively referred to as air cooling channels) are provided in the same manner on the trough bodies of the heating trough and the equalizing trough (for the sake of convenience of description, hereinafter collectively referred to as trough bodies); the air inlet and air outlet of the air cooling channel can be provided on the side wall on the same side of the trough body at the same time, or can be provided on the opposite side walls respectively. When the air inlet and air outlet of the air cooling channel are both provided on the same side wall (left wall or right wall) of the trough body, the air cooling channel is a round-trip two-way channel which passes through the inside of the left side wall of the trough body, the inside of the bottom wall of the trough body, the inside of the right side wall of the trough body, the inside of the bottom wall of the trough body, and the inside of the left side wall of the trough body in sequence. Air-cooled air (cold water can also be used if necessary) enters the air cooling channel from the air inlet, and cools each side wall of the trough body in a zigzag flow manner before being discharged from the air outlet (such as Figure 8-10 As shown), the temperature of the side wall of the trough body is controlled below 300°C (preferably below 150°C) by air cooling, and the cold air volume is adjusted and controlled according to the actual working conditions, so that the temperature of the cold air discharged from the air outlet does not exceed 200°C (preferably 150-180°C). If the temperature is too high, increase the air volume; if the temperature is too low, reduce the air volume. In addition, since the discharged hot air has a certain temperature and rich oxygen content, this part of the hot air circulation can be used as the combustion air for the heating burner and the uniform heat burner. Under the premise of ensuring that the combustion air volume is sufficient, the excess hot air can be used in other processes or discharged through the venting pipe to ensure the safe and stable operation of the system.

[0046] In the present invention, in order to improve the problems of long time and inaccurate feeding amount of traditional heating furnace charge, the present invention adds a storage bin (i.e., cache bin) that can quickly feed and has a weighing function. The storage bin is connected to the support of the soaking section through a hook. During the storage stage, the scrap steel discharged from the soaking section is transported forward to the storage bin. The storage bin is equipped with a weighing device, and the feeding is stopped after the weighing weight reaches the process requirements. During the scrap steel heating and storage stage, the scrap steel gate (i.e., the discharge gate) and the sealing gate are in a closed state. The scrap steel gate is used to bear the weight of the scrap steel, and the sealing gate is used to prevent external smoke from entering the negative pressure furnace through the unloading section. When it is necessary to feed the ladle through the storage bin, the scrap steel gate and the sealing gate are opened, and the scrap steel in the storage bin falls into the ladle. After the feeding is completed, the sealing gate and the scrap steel gate are closed in sequence. Considering that the material trough and the scrap steel gate need to withstand high temperature, the impact and wear of the scrap steel, it is preferably made of high chromium cast iron. Furthermore, the heat soaking hood extends backward (in the direction of the material flow) and is arranged on the feed port of the unloading mechanism. The hot flue gas in the heat soaking hood can enter the storage bin together with the material to form a hot atmosphere, ensuring that the temperature in the bin is between 600 and 800°C, effectively ensuring that the heated scrap steel will not be cooled in the bin due to heat dissipation during the waiting process of the ladle. The hot flue gas in the heat soaking hood can also be introduced into the storage bin through a pipeline, or the bin wall of the storage bin can be designed as a sandwich structure, and the hot flue gas is introduced into the sandwich layer of the bin wall to form an insulation layer.

[0047] Furthermore, the storage bin is a cone-shaped structure that is wide at the top and narrow at the bottom. Preferably, one side wall of the storage bin is a vertical side wall, and the other side walls are arc-shaped side walls as a whole. The arc-shaped side wall is a structure of the fastest descent curve, specifically: with the bottom end of the vertical side wall of the buffer bin 402 as the origin, the curve formed by the arc-shaped side wall satisfies:

[0048] When γ∈(π,2π), y=D 4 ·(γ-sinγ-π),z=H·[(cosγ-1)+2].

[0049] Among them, γ is the intermediate variable, y is the coordinate of the buffer silo in the length direction, and z is the coordinate of the buffer silo in the height direction. 4 is the length of the opening at the top of the buffer silo 402. H is the height of the vertical side wall of the buffer silo. Preferably, D 4 =H. In addition, the silo can withstand a volume of V = [3 / 2r 2 +D 4 (D 5 -H)]D 6 , where D 5 D is the vertical height between the discharge port of the silo and the discharge port of the soaking section; 6 It is the depth of the silo vertical to the paper surface (i.e. the width of the opening above the buffer silo), which is slightly larger than the depth of the heat trough vertical to the paper surface. According to the process requirements, m = g·Vρ s,d, m is the amount of scrap steel that needs to be added to the ladle at one time. ρ s,d is the bulk density of scrap steel. g is the surplus coefficient, which ensures that there is a certain amount of space left after the silo is filled with the required amount of scrap steel. The general value is 1.2 to 1.4.

[0050] In the utility model, a negative pressure hood connected to the heating hood is provided between the feeding trough and the heating trough, and an axial flow fan is provided inside the negative pressure hood. When working, the axial flow fan rotates to form a negative pressure close to that inside the heating hood, preventing the hot air inside the heating hood from escaping from the left side, and also preventing the cold air from the left side from entering the inside of the heating hood. The negative pressure inside the heating hood (denoted as P1) is monitored by a pressure sensor provided inside the heating hood close to the negative pressure hood side. A pressure sensor is also provided inside the negative pressure hood to monitor its internal negative pressure (denoted as P2). The two pressure sensors feed back signals to the central control program to adjust the rotation speed of the axial flow fan inside the negative pressure hood (i.e., the pressure sensor and the axial flow fan are linked) to maintain the pressure inside the negative pressure hood consistent with the pressure inside the heating hood (i.e., P1≈P2) to prevent wind from blowing.

[0051] In the utility model, the air outlets of the side exhaust ducts (heating side exhaust ducts and equalizing side exhaust ducts, hereinafter collectively referred to as side exhaust ducts) are connected to the air inlet end of the main flue gas discharge duct through the side exhaust air supply duct and the side exhaust fan. The side exhaust air supply duct is connected to the air outlet of the side exhaust duct through a dynamic and static connecting hose, and a heating flue gas temperature detector is arranged in the dynamic and static connecting hose. After the flue gas is extracted from the inside through the side exhaust duct, it passes through the dynamic and static connecting hose and then flows into the side exhaust air supply duct. A thermocouple is arranged in the dynamic and static connecting hose to detect the side exhaust smoke temperature. On the one hand, it is to prevent the smoke temperature from being too high (more than 400°C) and affecting the service life of the hose. On the other hand, it is to control the preheating effect of the scrap steel according to the temperature of the smoke extracted from the side.

[0052] In the utility model, in order to realize that the heating power can be adjusted according to the weight of scrap steel and the heating state, the utility model designs high fire mode, low fire mode and insulation mode for the heating of burners (heating burners and equalizing burners) (it can also be designed as more levels of modes, which can be reasonably designed according to the actual working conditions). The above energy supply is achieved by controlling the air and gas flow rates of the burners. Taking the high fire mode, low fire mode and insulation mode as examples, the corresponding parameters are shown in the following table.

[0053] Gas flow Air flow Fire Mode <![CDATA[Q fuel ]]> <![CDATA[Q air ]]> Low fire mode <![CDATA[0.6Q fuel ]]> <![CDATA[0.6Q air ]]> Keep Warm Mode <![CDATA[0.2Q fuel ]]> <![CDATA[0.2Q air ]]>

[0054] Among them, Q fuel It is calculated based on the amount of scrap steel that needs to be added to the ladle at one time (m (kg)) and the average heating temperature of the scrap steel △T (℃). Assuming the calorific value of the gas is ΔH (kJ / m 3 ), the heating efficiency is η, then there is a relationship:

[0055] C p m(△TT∞ ) = η·Q fuel ·ΔH;C p is the specific heat capacity of scrap steel, generally taken as 0.669 kJ / (kg℃). Then:

[0056] Q fuel =C p ·m(T c -T ∞ ) / (η·ΔH)

[0057] Q air＝ β·Q fuel-air

[0058] Where β is the excess air coefficient, which is generally 1.05 to 1.15, Q fuel-air Q fuel The amount of combustion air required for complete combustion of gas is obtained based on the chemical reaction equation.

[0059] Compared with the prior art, the beneficial technical effects of the utility model are as follows:

[0060] 1: The scrap steel preheating system of the utility model has a high overall preheating temperature for scrap steel: by adopting the bottom side extraction method, a part of the high-temperature flue gas flows from top to bottom, which changes the heat exchange mode of the traditional horizontal preheating device that only relies on inefficient radiation heat exchange. The flue gas can efficiently transfer heat to the scrap steel by convection. On the other hand, the side extraction ports at the bottom of the heating section and the soaking section have different depths, which ensures that the edges of the scrap steel can be fully insulated in the soaking section. The above method can increase the preheating temperature of the scrap steel, and the overall temperature can exceed 800°C or even 1000°C.

[0061] 2: The scrap steel preheating system of the utility model has high energy utilization efficiency: on the one hand, there is significant convection heat exchange between the scrap steel and the flue gas, the heat exchange efficiency is high, and the high temperature generated by the fuel combustion can be more effectively transferred to the scrap steel; on the other hand, the cooling gas of the trough, after cooling the trough, exchanges heat with the high-temperature flue gas together with the combustion-supporting air that needs to be supplemented, and enters the furnace as the combustion-supporting gas, thereby dissipating the cooling heat of the trough and recovering the waste heat of the flue gas, which can also improve the thermal efficiency of the preheating furnace.

[0062] 3: The utility model has a low failure rate of scrap steel preheating system equipment: the scrap steel is transported by horizontal vibration feeding, which can achieve stable and uniform feeding. The inclination curve of the buffer bin is a unique inverse sine function shape, which avoids the problems of scrap steel accumulation and jamming during unloading, which affect the operation of the equipment. When unloading, you only need to open the unloading gate to use the dead weight of the scrap steel to unload.

[0063] 4: The scrap steel preheating system of the utility model can accurately and stably control the amount of scrap steel discharged from the furnace through the weighing hopper, and can be coordinated with the converter or electric furnace during the steelmaking process to maximize the increase in production. In addition, the system of the utility model also has the advantages of simple structure, low investment cost, low energy consumption, and high production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic diagram of the overall structure of the scrap steel preheating system of the utility model.

[0065] Figure 2 It is a cross-sectional schematic diagram of the feeding trough of the utility model.

[0066] Figure 3 It is a cross-sectional schematic diagram of the heating trough of the utility model.

[0067] Figure 4 The figure is a schematic diagram of the high-temperature flue gas flow route in the heating trough of the utility model.

[0068] Figure 5 It is a cross-sectional schematic diagram of the heat equalizing trough of the utility model.

[0069] Figure 6 The figure is a schematic diagram of the high-temperature flue gas flow route in the heat-equalizing trough of the utility model.

[0070] Figure 7 It is a schematic diagram of the connection relationship between the heating air cooling channel (or the uniform heating air cooling channel) and the side exhaust air duct of the utility model.

[0071] Figure 8 It is a schematic diagram of the distribution of the air cooling channel in the left wall of the heating trough and the equalizing trough of the utility model.

[0072] Fig. 9 It is a schematic diagram of the distribution of air cooling channels in the bottom side walls of the heating trough and the heat equalizing trough of the utility model.

[0073] Fig.10 It is a distribution diagram of the air cooling channel in the right wall of the heating trough and the heat equalizing trough of the utility model.

[0074] Fig.11 It is an enlarged schematic diagram of the unloading mechanism of the utility model.

[0075] Fig.12 It is a schematic diagram of the hot flue gas flow direction when the side exhaust volume of the heating trough (or equalizing trough) of the utility model is insufficient.

[0076] Fig.13 It is a schematic diagram of the hot flue gas flow direction when the side exhaust volume of the heating trough (or equalizing trough) of the utility model is better.

[0077] Fig.14It is a schematic diagram of the hot flue gas flow direction when the side exhaust volume of the heating trough (or equalizing trough) of the utility model is too large.

[0078] Reference numerals: 1: feeding trough; 2: heating trough; 201: heating cover; 202: heating burner; 203: heating side exhaust duct; 204: heating air cooling channel; 3: uniform heating trough; 301: uniform heating cover; 302: uniform heating burner; 303: uniform heating side exhaust duct; 304: uniform heating air cooling channel; 4: unloading mechanism; 401: dust removal hood; 402: buffer silo; 403: unloading valve; 4031: Discharge gate; 4032: Sealing gate; 5: Vibrating horizontal feeding drive device; 6: Gas pipeline; 7: Combustion-supporting air duct; 8: Combustion-supporting fan; 9: Main flue gas discharge pipeline; 10: Main exhaust fan; 11: Indirect heat exchanger; 12: Negative pressure hood; 1201: Axial flow fan; 1202: Flat feeder; 13: Pressure sensor; 14: Magnetic suction cup; 15: Feeding crane; 16: Side exhaust air duct; 17: Side exhaust fan. DETAILED DESCRIPTION

[0079] The technical solution of the utility model is illustrated below, and the scope of protection requested for the utility model includes but is not limited to the following embodiments.

[0080] A scrap steel preheating system, the system comprises a feeding trough 1, a heating trough 2, a heat equalizing trough 3 and a discharge mechanism 4 which are connected in series in sequence. The feeding trough 1, the heating trough 2 and the heat equalizing trough 3 are all U-shaped trough structures with an open upper end. A heating cover 201 is provided above the heating trough 2, and a heating burner 202 is provided in the heating cover 201, and a heating side exhaust duct 203 is provided at the bottom of the heating trough 2. A heat equalizing trough 301 is provided above the heat equalizing trough 3, and a heat equalizing burner 302 is provided in the heat equalizing trough 301, and a heat equalizing side exhaust duct 303 is provided at the bottom of the heat equalizing trough 3. A vibration horizontal feeding drive device 5 is also provided at the front end of the feeding trough 1, and the vibration horizontal feeding drive device 5 drives the material to flow through the feeding trough 1, the heating trough 2 and the heat equalizing trough 3 in sequence and then be discharged from the discharge mechanism 4.

[0081] Preferably, the heating burner 202 and the equalizing burner 302 are both connected with a gas pipeline 6 and a combustion-supporting air duct 7, and a combustion-supporting fan 8 is provided on the combustion-supporting air duct 7. The air outlet of the equalizing hood 301 is connected to the main exhaust fan 10 through the main flue gas exhaust duct 9.

[0082] Preferably, a heating side exhaust duct 203 extending along the width direction is provided on each of the two sides of the bottom wall surface of the heating trough 2. The air inlet ends of the two heating side exhaust ducts 203 extend toward each other along the bottom surface of the heating trough 2 and approach the middle of the bottom surface of the heating trough 2, and the other ends thereof penetrate the side walls of the heating trough 2 and extend to the outside. A first horizontal spacing is left between the air inlet ends of the two heating side exhaust ducts 203.

[0083] Preferably, the heating side exhaust duct 203 located on either side of the bottom of the heating trough 2 includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heating trough 2, or the heating side exhaust duct 203 located on either side of the bottom of the heating trough 2 is a flat exhaust cavity extending along the length direction of the heating trough 2. The air outlets of the heating side exhaust duct 203 are connected to the air inlet end of the main flue gas discharge duct 9 through the side exhaust air duct 16 and the side exhaust fan 17. Preferably, the side exhaust air duct 16 is connected to the air outlet of the heating side exhaust duct 203 through a dynamic and static connecting hose, and a heating flue gas temperature detector is provided in the dynamic and static connecting hose.

[0084] Preferably, the heating cover 201 is an arc-shaped structure, and a pair of heating burners 202 are arranged on the cover body located on both sides of the arc top of the heating cover 201. Preferably, in the length direction of the heating trough 2, the heating cover 201 is provided with multiple pairs of symmetrically arranged heating burners 202.

[0085] Preferably, the heat hood 301 is an arc-shaped structure, and a heat absorbing burner 302 is provided on the hood body located at the top of the arc of the heat absorbing hood 301. Preferably, a plurality of heat absorbing burners 302 are provided on the heat absorbing hood 301 in the length direction of the heat absorbing trough 3. The heat absorbing hood 301 extends backward and is provided on the feed port of the discharge mechanism 4.

[0086] Preferably, the angle formed between the axis of the heating burner 202 and the horizontal plane is α, wherein 10°≤α≤80°, preferably 30°≤α≤60°.

[0087] Preferably, the first horizontal distance is D 1 , and there is: k·D 1 <2(R 1 -L 1 )cosα. Where: R 1 is the arc radius of the heating hood 201, L 1 is the flame length of the heating burner 202, k is a correction factor and 1.5≤k≤2.

[0088] Preferably, a heat-equalizing side exhaust duct 303 extending along the width direction is provided on each of the two sides of the bottom wall surface of the heat-equalizing material tank 3. The air inlet ends of the two heat-equalizing side exhaust ducts 303 extend toward each other along the bottom surface of the heat-equalizing material tank 3 and approach the middle of the bottom surface of the heat-equalizing material tank 3, and the other ends thereof respectively penetrate the side walls of the heat-equalizing material tank 3 and extend to the outside. A second horizontal spacing is left between the air inlet ends of the two heat-equalizing side exhaust ducts 303.

[0089] Preferably, the heat-equalizing side exhaust duct 303 located on either side of the bottom of the heat-equalizing material tank 3 includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heat-equalizing material tank 3, or the heat-equalizing side exhaust duct 303 located on either side of the bottom of the heat-equalizing material tank 3 is a flat exhaust clip cavity extending along the length direction of the heat-equalizing material tank 3. The air outlets of the heat-equalizing side exhaust duct 303 are connected to the air inlet end of the main flue gas discharge duct 9 through the side exhaust air duct 16 and the side exhaust fan 17. Preferably, the side exhaust air duct 16 is connected to the air outlet of the heat-equalizing side exhaust duct 303 through a dynamic and static connecting hose, and a heat-equalizing flue gas temperature detector is provided in the dynamic and static connecting hose.

[0090] Preferably, the second horizontal distance is D 2 , and: 0.75<D 2 / D 3 <0.9. Among them: D 3 is the width of the heat equalizing tank 3.

[0091] Preferably, an indirect heat exchanger 11 is further provided between the main flue gas discharge pipe 9 and the combustion-supporting air pipe 7 .

[0092] Preferably, a heating air cooling channel 204 is provided inside the trough wall of the heating trough 2. The air inlet and the air outlet of the heating air cooling channel 204 are both provided on the side wall of the heating trough 2.

[0093] Preferably, the air inlet and the air outlet of the heating air cooling channel 204 are respectively opened on the left wall and the right wall of the heating trough 2. That is, the heating air cooling channel 204 is a one-way channel passing through the inside of the left wall of the heating trough 2, the inside of the bottom wall of the heating trough 2, and the inside of the right wall of the heating trough 2 in sequence.

[0094] Alternatively, the air inlet and the air outlet of the heating air cooling channel 204 are both opened on the left side wall of the heating trough 2. The heating air cooling channel 204 is a round-trip two-way channel that passes through the inside of the left side wall of the heating trough 2, the inside of the bottom wall of the heating trough 2, the inside of the right side wall of the heating trough 2, the inside of the bottom wall of the heating trough 2, and the inside of the left side wall of the heating trough 2 in sequence.

[0095] Preferably, the air outlet of the heating air cooling channel 204 is connected to the air inlet end of the combustion-supporting fan 8 through a circulating air duct. Preferably, a venting branch pipe and a venting valve are provided on the circulating air duct.

[0096] Preferably, a heat-equalizing air-cooling channel 304 is provided inside the wall of the heat-equalizing material tank 3. The air inlet and the air outlet of the heat-equalizing air-cooling channel 304 are both provided on the side wall of the heat-equalizing material tank 3.

[0097] Preferably, the air inlet and the air outlet of the heat-averaging air cooling channel 304 are respectively opened on the left wall and the right wall of the heat-averaging material tank 3. That is, the heat-averaging air cooling channel 304 is a one-way channel passing through the left wall of the heat-averaging material tank 3, the bottom wall of the heat-averaging material tank 3, and the right wall of the heat-averaging material tank 3 in sequence.

[0098] Alternatively, the air inlet and the air outlet of the heat-averaging air-cooling channel 304 are both opened on the left wall of the heat-averaging material tank 3. The heat-averaging air-cooling channel 304 is a round-trip two-way channel that passes through the inside of the left wall of the heat-averaging material tank 3, the inside of the bottom wall of the heat-averaging material tank 3, the inside of the right wall of the heat-averaging material tank 3, the inside of the bottom wall of the heat-averaging material tank 3, and the inside of the left wall of the heat-averaging material tank 3 in sequence.

[0099] Preferably, the air outlet of the heat-averaging air cooling channel 304 is connected to the air inlet end of the combustion-supporting fan 8 through a circulating air duct. Preferably, a venting branch pipe and a venting valve are provided on the circulating air duct.

[0100] Preferably, the unloading mechanism 4 includes a dust removal hood 401 and a buffer bin 402. The buffer bin 402 is arranged below the discharge end of the heat equalizing trough 3, and the feed port of the buffer bin 402 is connected to the discharge end of the heat equalizing trough 3, and the dust removal hood 401 is arranged between the feed port of the buffer bin 402 and the discharge end of the heat equalizing trough 3. The air outlet on the dust removal hood 401 is connected to the main exhaust fan 10 through a pipeline. A discharge valve 403 is arranged at the lower part of the side wall of the buffer bin 402.

[0101] Preferably, the buffer silo 402 is a cone-shaped structure that is wide at the top and narrow at the bottom. Preferably, one side wall of the buffer silo 402 is a vertical side wall, and the other side walls are arc-shaped side walls as a whole. Preferably, a weighing meter is also provided on the buffer silo 402.

[0102] Preferably, the discharge valve 403 comprises a discharge gate 4031 and a sealing gate 4032. The discharge gate 4031 and the sealing gate 4032 are both arranged on the vertical side wall, wherein the sealing gate 4032 is located outside the discharge side of the discharge gate 4031 and completely covers the discharge gate 4031.

[0103] Preferably, the arc-shaped side wall is a steepest descent curve structure, specifically: with the bottom end of the vertical side wall of the buffer bin 402 as the origin, the curve formed by the arc-shaped side wall satisfies:

[0104] When γ∈(π,2π), y=D 4 ·(γ-sinγ-π),z=H·[(cosγ-1)+2].

[0105] Wherein, γ is an intermediate variable; y is the coordinate of the buffer bin 402 in the length direction; z is the coordinate of the buffer bin 402 in the height direction. 4 is the length of the opening at the top of the buffer bin 402. H is the height of the vertical side wall of the buffer bin 402. Preferably, D 4 =H.

[0106] Preferably, the system further comprises a negative pressure cover 12. The negative pressure cover 12 is arranged between the feeding tank 1 and the heating tank 2, and is connected to the heating cover 201. An axial flow fan 1201 is arranged in the negative pressure cover 12. A pressure sensor 13 is independently arranged in the negative pressure cover 12 and the heating cover 201, and the pressure sensor 13 is linked to the axial flow fan 1201.

[0107] Preferably, a flattener 1202 is also provided at the feeding end of the negative pressure hood 12 .

[0108] Preferably, a feeding mechanism is further provided above the feeding trough 1. Preferably, the feeding mechanism is a feeding overhead crane 15 having a magnetic chuck 14.

[0109] Example 1

[0110] like Figure 1-14 As shown, a scrap steel preheating system comprises a feeding trough 1, a heating trough 2, a heat equalizing trough 3 and a discharge mechanism 4 which are connected in series in sequence. The feeding trough 1, the heating trough 2 and the heat equalizing trough 3 are all U-shaped trough structures with an open upper end. A heating cover 201 is provided above the heating trough 2, and a heating burner 202 is provided in the heating cover 201, and a heating side exhaust duct 203 is provided at the bottom of the heating trough 2. A heat equalizing trough 301 is provided above the heat equalizing trough 3, and a heat equalizing burner 302 is provided in the heat equalizing trough 301, and a heat equalizing side exhaust duct 303 is provided at the bottom of the heat equalizing trough 3. A vibration horizontal feeding drive device 5 is also provided at the front end of the feeding trough 1, and the vibration horizontal feeding drive device 5 drives the material to flow through the feeding trough 1, the heating trough 2 and the heat equalizing trough 3 in sequence and then be discharged from the discharge mechanism 4.

[0111] Example 2

[0112] Example 1 is repeated, except that the heating burner 202 and the equalizing burner 302 are both connected with a gas pipeline 6 and a combustion-supporting air duct 7, and a combustion-supporting fan 8 is provided on the combustion-supporting air duct 7. The air outlet of the equalizing hood 301 is connected to the main exhaust fan 10 through the main flue gas exhaust duct 9.

[0113] Example 3

[0114] Example 2 is repeated, except that a heating side exhaust duct 203 extending along the width direction is provided on both sides of the bottom wall surface of the heating trough 2. The air inlet ends of the two heating side exhaust ducts 203 extend toward each other along the bottom surface of the heating trough 2 and approach the middle of the bottom surface of the heating trough 2, and their other ends respectively penetrate the side walls of the heating trough 2 and extend to the outside. A first horizontal spacing is left between the air inlet ends of the two heating side exhaust ducts 203.

[0115] Example 4

[0116] Example 3 is repeated, except that the heating side exhaust duct 203 located on either side of the bottom of the heating trough 2 includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heating trough 2, or the heating side exhaust duct 203 located on either side of the bottom of the heating trough 2 is a flat exhaust clip cavity extending along the length direction of the heating trough 2. The air outlet of the heating side exhaust duct 203 is connected to the air inlet end of the main flue gas discharge duct 9 through the side exhaust air duct 16 and the side exhaust fan 17. The side exhaust air duct 16 is connected to the air outlet of the heating side exhaust duct 203 through a dynamic and static connecting hose, and a heating flue gas temperature detector is arranged in the dynamic and static connecting hose.

[0117] Example 5

[0118] The fourth embodiment is repeated, except that the heating hood 201 is an arc-shaped structure, and a pair of heating burners 202 are provided on the hood body located on both sides of the arc top of the heating hood 201 .

[0119] Example 6

[0120] Example 5 is repeated, except that a plurality of pairs of symmetrically arranged heating burners 202 are provided on the heating cover 201 in the length direction of the heating trough 2 .

[0121] Example 7

[0122] The embodiment 6 is repeated, except that the heat hood 301 is an arc-shaped structure, and a heat burner 302 is provided on the hood body located at the arc top of the heat hood 301 .

[0123] Example 8

[0124] The embodiment 7 is repeated, except that a plurality of heat-absorbing burners 302 are arranged on the heat-absorbing cover 301 in the length direction of the heat-absorbing trough 3. The heat-absorbing cover 301 extends backward and is arranged on the feed port of the discharge mechanism 4.

[0125] Example 9

[0126] Example 8 is repeated, except that the angle formed between the axis of the heating burner 202 and the horizontal plane is α, where α=45°.

[0127] Example 10

[0128] Repeat Example 9, except that the first horizontal spacing is D 1 , and there is: k·D 1 <2(R 1 -L 1 )cosα. Where: R 1 is the arc radius of the heating hood 201, L 1 is the flame length of the heating burner 202, k is the correction factor and k=1.79.

[0129] Embodiment 11

[0130] Example 10 is repeated, except that a heat-equalizing side exhaust duct 303 extending along the width direction is provided on both sides of the bottom wall surface of the heat-equalizing material tank 3. The air inlet ends of the two heat-equalizing side exhaust ducts 303 extend toward each other along the bottom surface of the heat-equalizing material tank 3 and approach the middle of the bottom surface of the heat-equalizing material tank 3, and their other ends respectively penetrate the side walls of the heat-equalizing material tank 3 and extend to the outside. A second horizontal spacing is left between the air inlet ends of the two heat-equalizing side exhaust ducts 303.

[0131] Example 12

[0132] Repeat Example 11, except that the heat-averaging side exhaust duct 303 located on either side of the bottom of the heat-averaging trough 3 includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heat-averaging trough 3, or the heat-averaging side exhaust duct 303 located on either side of the bottom of the heat-averaging trough 3 is a flat exhaust clip cavity extending along the length direction of the heat-averaging trough 3. The air outlets of the heat-averaging side exhaust duct 303 are connected to the air inlet end of the main flue gas discharge duct 9 through the side exhaust air duct 16 and the side exhaust fan 17. Preferably, the side exhaust air duct 16 is connected to the air outlet of the heat-averaging side exhaust duct 303 through a dynamic and static connecting hose, and a heat-averaging flue gas temperature detector is provided in the dynamic and static connecting hose.

[0133] Embodiment 13

[0134] Repeat Example 12, except that the second horizontal spacing is D 2 , and there is: D 2 / D 3 =0.85. Where: D3 is the width of the heat equalizing tank 3.

[0135] Embodiment 14

[0136] Example 13 is repeated, except that an indirect heat exchanger 11 is further provided between the main flue gas discharge pipe 9 and the combustion-supporting air pipe 7 .

[0137] Embodiment 15

[0138] Example 14 is repeated, except that a heating air cooling channel 204 is opened inside the tank wall of the heating material tank 2. The air inlet and the air outlet of the heating air cooling channel 204 are both arranged on the side wall of the heating material tank 2.

[0139] Example 16

[0140] Example 15 is repeated, except that the air inlet and the air outlet of the heating air cooling channel 204 are respectively opened on the left wall and the right wall of the heating trough 2. That is, the heating air cooling channel 204 is a one-way channel that passes through the inside of the left wall of the heating trough 2, the inside of the bottom wall of the heating trough 2, and the inside of the right wall of the heating trough 2 in sequence.

[0141] Embodiment 17

[0142] Example 15 is repeated, except that the air inlet and the air outlet of the heating air cooling channel 204 are both opened on the left wall of the heating trough 2. The heating air cooling channel 204 is a round-trip two-way channel that passes through the inside of the left wall of the heating trough 2, the inside of the bottom wall of the heating trough 2, the inside of the right wall of the heating trough 2, the inside of the bottom wall of the heating trough 2, and the inside of the left wall of the heating trough 2 in sequence.

[0143] Embodiment 18

[0144] Example 17 is repeated, except that the air outlet of the heating air cooling channel 204 is connected to the air inlet end of the combustion-supporting fan 8 through a circulating air duct. The circulating air duct is provided with a relief branch pipe and a relief valve.

[0145] Embodiment 19

[0146] Example 18 is repeated, except that a heat-equalizing air-cooling channel 304 is opened inside the tank wall of the heat-equalizing tank 3. The air inlet and the air outlet of the heat-equalizing air-cooling channel 304 are both arranged on the side wall of the heat-equalizing tank 3.

[0147] Embodiment 20

[0148] Example 19 is repeated, except that the air inlet and the air outlet of the heat-averaging air-cooling channel 304 are respectively opened on the left wall and the right wall of the heat-averaging tank 3. That is, the heat-averaging air-cooling channel 304 is a one-way channel that passes through the inside of the left wall of the heat-averaging tank 3, the inside of the bottom wall of the heat-averaging tank 3, and the inside of the right wall of the heat-averaging tank 3 in sequence.

[0149] Embodiment 21

[0150] Example 19 is repeated, except that the air inlet and the air outlet of the heat-averaging air-cooling channel 304 are both opened on the left wall of the heat-averaging tank 3. The heat-averaging air-cooling channel 304 is a round-trip two-way channel that passes through the inside of the left wall of the heat-averaging tank 3, the inside of the bottom wall of the heat-averaging tank 3, the inside of the right wall of the heat-averaging tank 3, the inside of the bottom wall of the heat-averaging tank 3, and the inside of the left wall of the heat-averaging tank 3 in sequence.

[0151] Embodiment 22

[0152] Example 21 is repeated, except that the air outlet of the heat-averaging air cooling channel 304 is connected to the air inlet end of the combustion-supporting fan 8 through a circulating air duct.

[0153] Embodiment 23

[0154] Repeat Example 22, except that the unloading mechanism 4 includes a dust removal hood 401 and a buffer bin 402. The buffer bin 402 is arranged below the discharge end of the heat equalizing trough 3, and the feed port of the buffer bin 402 is connected to the discharge end of the heat equalizing trough 3, and the dust removal hood 401 is arranged between the feed port of the buffer bin 402 and the discharge end of the heat equalizing trough 3. The air outlet on the dust removal hood 401 is connected to the main exhaust fan 10 through a pipeline. A discharge valve 403 is arranged at the lower part of the side wall of the buffer bin 402.

[0155] Embodiment 24

[0156] Example 23 is repeated, except that the buffer bin 402 is a cone-shaped structure that is wide at the top and narrow at the bottom. Preferably, one side wall of the buffer bin 402 is a vertical side wall, and the other side walls are arc-shaped side walls as a whole. The buffer bin 402 is also provided with a weighing meter.

[0157] Embodiment 25

[0158] Example 24 is repeated, except that the discharge valve 403 includes a discharge gate 4031 and a sealing gate 4032. The discharge gate 4031 and the sealing gate 4032 are both arranged on the vertical side wall, wherein the sealing gate 4032 is located outside the discharge side of the discharge gate 4031 and completely covers the discharge gate 4031.

[0159] Embodiment 26

[0160] Example 25 is repeated, except that the arc-shaped side wall is a structure of the steepest descent curve. Specifically, with the bottom end of the vertical side wall of the buffer bin 402 as the origin, the curve formed by the arc-shaped side wall satisfies:

[0161] When γ∈(π,2π), y=D 4 ·(γ-sinγ-π),z=H·[(cosγ-1)+2].

[0162] Wherein, γ is an intermediate variable; y is the coordinate of the buffer bin 402 in the length direction; z is the coordinate of the buffer bin 402 in the height direction. 4 is the length of the opening at the top of the buffer bin 402. H is the height of the vertical side wall of the buffer bin 402. 4 =H.

[0163] Embodiment 27

[0164] Example 26 is repeated, except that the system further includes a negative pressure cover 12. The negative pressure cover 12 is disposed between the feeding tank 1 and the heating tank 2, and is connected to the heating cover 201. An axial flow fan 1201 is disposed in the negative pressure cover 12. A pressure sensor 13 is independently disposed in the negative pressure cover 12 and the heating cover 201, and the pressure sensor 13 is linked to the axial flow fan 1201.

[0165] Embodiment 28

[0166] Repeat Example 27, except that a flat material feeder 1202 is also provided at the feed end of the negative pressure hood 12.

[0167] Embodiment 29

[0168] The embodiment 28 is repeated, except that a feeding mechanism is further provided above the feeding trough 1. The feeding mechanism is a feeding overhead crane 15 having a magnetic chuck 14.

Claims

1. A scrap steel preheating system, characterized in that: The system comprises a feeding trough (1), a heating trough (2), a heat equalizing trough (3) and a discharge mechanism (4) which are connected in series in sequence; the feeding trough (1), the heating trough (2) and the heat equalizing trough (3) are all U-shaped trough structures with an open top; a heating hood (201) is provided above the heating trough (2), a heating burner (202) is provided in the heating hood (201), and a heating side exhaust duct (203) is provided at the bottom of the heating trough (2); A heat equalizing hood (301) is provided above the material trough (3), and a heat equalizing burner (302) is provided inside the heat equalizing hood (301); a heat equalizing side exhaust duct (303) is provided at the bottom of the heat equalizing trough (3); a vibrating horizontal feeding drive device (5) is also provided at the front end of the feeding trough (1), and the material is driven by the vibrating horizontal feeding drive device (5) to flow through the feeding trough (1), the heating trough (2), and the heat equalizing trough (3) in sequence and then discharged from the unloading mechanism (4).

2. The system according to claim 1, characterized in that: The heating burner (202) and the equalizing burner (302) are both connected to a gas pipeline (6) and a combustion-supporting air duct (7), and the combustion-supporting air duct (7) is provided with a combustion-supporting fan (8); the air outlet of the equalizing hood (301) is connected to a main exhaust fan (10) via a main smoke exhaust duct (9).

3. The system according to claim 2, characterized in that: A heating side exhaust duct (203) extending along the width direction is provided on each side of the bottom wall surface of the heating trough (2); the air inlet ends of the two heating side exhaust ducts (203) extend toward each other along the bottom surface of the heating trough (2) and approach the middle of the bottom surface of the heating trough (2), and their other ends respectively penetrate the side walls of the heating trough (2) and extend to the outside; a first horizontal spacing is left between the air inlet ends of the two heating side exhaust ducts (203).

4. The system according to claim 3, characterized in that: The heating side exhaust duct (203) located on either side of the bottom of the heating trough (2) includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heating trough (2), or the heating side exhaust duct (203) located on either side of the bottom of the heating trough (2) is a flat exhaust cavity extending along the length direction of the heating trough (2); the air outlet of the heating side exhaust duct (203) is connected to the air inlet end of the main smoke exhaust duct (9) through the side exhaust air supply pipe (16) and the side exhaust fan (17).

5. The system according to claim 4, characterized in that: The side exhaust air pipe (16) is connected to the air outlet of the heating side exhaust duct (203) via a dynamic-static connecting hose, and a heating smoke temperature detector is arranged in the dynamic-static connecting hose.

6. The system according to claim 1, characterized in that: The heating hood (201) is an arc-shaped structure, and a pair of heating burners (202) are arranged on the hood body located on both sides of the arc top of the heating hood (201); and / or The heat-saturating hood (301) is an arc-shaped structure, and a heat-saturating burner (302) is arranged on the hood body located at the arc top of the heat-saturating hood (301).

7. The system according to claim 6, characterized in that: In the length direction of the heating trough (2), a plurality of pairs of symmetrically arranged heating burners (202) are arranged on the heating cover (201); and / or In the length direction of the heat-averaging trough (3), a plurality of heat-averaging burners (302) are arranged on the heat-averaging cover (301); the heat-averaging cover (301) extends backwards and is arranged on the feed port of the discharge mechanism (4).

8. The system according to claim 3, characterized in that: The angle formed between the axis of the heating burner (202) and the horizontal plane is α, wherein 10°≤α≤80°.

9. The system according to claim 8, characterized in that: 30°≤α≤60°.

10. The system according to claim 8, characterized in that: The first horizontal spacing is D1, and: k·D1<2(R1-L1)cosα; wherein: R1 is the arc radius of the heating hood (201), m; L1 is the flame length of the heating burner (202), m; k is the correction coefficient and 1.5≤k≤2.

11. The system according to claim 2, characterized in that: A heat-equalizing side exhaust duct (303) extending along the width direction is provided on each side of the bottom wall surface of the heat-equalizing trough (3); the air inlet ends of the two heat-equalizing side exhaust ducts (303) extend toward each other along the bottom surface of the heat-equalizing trough (3) and approach the middle of the bottom surface of the heat-equalizing trough (3), and their other ends respectively penetrate the side walls of the heat-equalizing trough (3) and extend to the outside; a second horizontal spacing is left between the air inlet ends of the two heat-equalizing side exhaust ducts (303).

12. The system according to claim 11, characterized in that: The heat-equalizing side exhaust duct (303) located on either side of the bottom of the heat-equalizing material trough (3) includes a plurality of independent exhaust ducts arranged in parallel along the length direction of the heat-equalizing material trough (3), or the heat-equalizing side exhaust duct (303) located on either side of the bottom of the heat-equalizing material trough (3) is a flat exhaust cavity extending along the length direction of the heat-equalizing material trough (3); the air outlet of the heat-equalizing side exhaust duct (303) is connected to the air inlet end of the main smoke exhaust duct (9) through the side exhaust air supply pipe (16) and the side exhaust fan (17).

13. The system according to claim 12, characterized in that: The side exhaust air supply pipe (16) is connected to the air outlet of the evenly heated side exhaust duct (303) via a dynamic and static connecting hose, and an evenly heated smoke temperature detector is arranged in the dynamic and static connecting hose.

14. The system according to claim 12, characterized in that: The second horizontal spacing is D2, and the following is true: 0.75<D2 / D3<0.9; wherein: D3 is the width of the heat-saturating trough (3); and / or An indirect heat exchanger (11) is also provided between the main smoke exhaust pipe (9) and the combustion-supporting air pipe (7).

15. The system according to any one of claims 1 to 14, characterized in that: A heating air cooling channel (204) is provided inside the trough wall of the heating material trough (2); the air inlet and the air outlet of the heating air cooling channel (204) are both arranged on the side wall of the heating material trough (2).

16. The system according to claim 15, characterized in that: The air inlet and the air outlet of the heating air cooling channel (204) are respectively arranged on the left wall and the right wall of the heating material trough (2); that is, the heating air cooling channel (204) is a one-way channel which passes through the inside of the left wall of the heating material trough (2), the inside of the bottom wall of the heating material trough (2) and the inside of the right wall of the heating material trough (2) in sequence; Alternatively, the air inlet and the air outlet of the heating air cooling channel (204) are both opened on the left side wall of the heating trough (2); the heating air cooling channel (204) is a round-trip two-way channel which passes through the inside of the left side wall of the heating trough (2), the inside of the bottom wall of the heating trough (2), the inside of the right side wall of the heating trough (2), the inside of the bottom wall of the heating trough (2) and the inside of the left side wall of the heating trough (2) in sequence.

17. The system according to claim 16, characterized in that: The air outlet of the heating air cooling channel (204) is connected to the air inlet end of the combustion-supporting fan (8) through a circulating air duct.

18. The system according to claim 17, characterized in that: The circulating air duct is provided with a relief branch pipe and a relief valve.

19. The system according to any one of claims 1 to 14, characterized in that: A heat-equalizing air-cooling channel (304) is provided inside the wall of the heat-equalizing material trough (3); the air inlet and the air outlet of the heat-equalizing air-cooling channel (304) are both arranged on the side wall of the heat-equalizing material trough (3).

20. The system according to claim 19, characterized in that: The air inlet and the air outlet of the heat-averaging air-cooling channel (304) are respectively arranged on the left and right walls of the heat-averaging material tank (3); that is, the heat-averaging air-cooling channel (304) is a one-way channel which passes through the inside of the left wall of the heat-averaging material tank (3), the inside of the bottom wall of the heat-averaging material tank (3), and the inside of the right wall of the heat-averaging material tank (3) in sequence; Alternatively, the air inlet and the air outlet of the heat-equalizing air-cooling channel (304) are both opened on the left side wall of the heat-equalizing material trough (3); the heat-equalizing air-cooling channel (304) is a round-trip two-way channel which passes through the inside of the left side wall of the heat-equalizing material trough (3), the inside of the bottom wall of the heat-equalizing material trough (3), the inside of the right side wall of the heat-equalizing material trough (3), the inside of the bottom wall of the heat-equalizing material trough (3) and the inside of the left side wall of the heat-equalizing material trough (3) in sequence.

21. The system according to claim 20, characterized in that: The air outlet of the heat-averaging air cooling channel (304) is connected to the air inlet end of the combustion-supporting fan (8) through a circulating air duct.

22. The system according to claim 21, characterized in that: The circulating air duct is provided with a relief branch pipe and a relief valve.

23. The system according to any one of claims 1-14, 16-18, 20-22, characterized in that: The unloading mechanism (4) comprises a dust removal hood (401) and a buffer bin (402); the buffer bin (402) is arranged below the discharge end of the heat equalizing trough (3), and the feed port of the buffer bin (402) is connected to the discharge end of the heat equalizing trough (3), and the dust removal hood (401) is arranged between the feed port of the buffer bin (402) and the discharge end of the heat equalizing trough (3); the air outlet on the dust removal hood (401) is connected to the main exhaust fan (10) through a pipeline; and a discharge valve (403) is arranged at the lower part of the side wall of the buffer bin (402).

24. The system according to claim 15, characterized in that: The unloading mechanism (4) comprises a dust removal hood (401) and a buffer bin (402); the buffer bin (402) is arranged below the discharge end of the heat equalizing trough (3), and the feed port of the buffer bin (402) is connected to the discharge end of the heat equalizing trough (3), and the dust removal hood (401) is arranged between the feed port of the buffer bin (402) and the discharge end of the heat equalizing trough (3); the air outlet on the dust removal hood (401) is connected to the main exhaust fan (10) through a pipeline; and a discharge valve (403) is arranged at the lower part of the side wall of the buffer bin (402).

25. The system according to claim 19, characterized in that: The unloading mechanism (4) comprises a dust removal hood (401) and a buffer bin (402); the buffer bin (402) is arranged below the discharge end of the heat equalizing trough (3), and the feed port of the buffer bin (402) is connected to the discharge end of the heat equalizing trough (3), and the dust removal hood (401) is arranged between the feed port of the buffer bin (402) and the discharge end of the heat equalizing trough (3); the air outlet on the dust removal hood (401) is connected to the main exhaust fan (10) through a pipeline; and a discharge valve (403) is arranged at the lower part of the side wall of the buffer bin (402).

26. The system according to claim 23, characterized in that: The buffer bin (402) is a cone-shaped structure that is wide at the top and narrow at the bottom.

27. The system according to claim 24 or 25, characterized in that: The buffer bin (402) is a cone-shaped structure that is wide at the top and narrow at the bottom.

28. The system according to claim 23, characterized in that: One side wall of the buffer bin (402) is a vertical side wall, and the other side walls are generally arc-shaped side walls.

29. The system according to claim 24 or 25, characterized in that: One side wall of the buffer bin (402) is a vertical side wall, and the other side walls are generally arc-shaped side walls.

30. The system according to claim 23, characterized in that: The buffer silo (402) is also provided with a weighing meter.

31. The system according to claim 24 or 25, characterized in that: The buffer silo (402) is also provided with a weighing meter.

32. The system according to claim 28, characterized in that: The discharge valve (403) comprises a discharge gate (4031) and a sealing gate (4032); the discharge gate (4031) and the sealing gate (4032) are both arranged on the vertical side wall, wherein the sealing gate (4032) is located outside the discharge side of the discharge gate (4031) and completely covers the discharge gate (4031); and / or The arc-shaped side wall is a structure of the steepest descent curve, specifically: with the bottom end of the vertical side wall of the buffer bin (402) as the origin, the curve formed by the arc-shaped side wall satisfies: When γ∈(π,2π), y=D4·(γ-sinγ-π), z=H·[(cosγ-1)+2]; Among them, γ is an intermediate variable; y is the coordinate of the cache bin (402) in the length direction; z is the coordinate of the cache bin (402) in the height direction; D4 is the opening length at the top of the cache bin (402); H is the height of the vertical side wall of the cache bin (402).

33. The system according to claim 29, characterized in that: The discharge valve (403) comprises a discharge gate (4031) and a sealing gate (4032); the discharge gate (4031) and the sealing gate (4032) are both arranged on the vertical side wall, wherein the sealing gate (4032) is located outside the discharge side of the discharge gate (4031) and completely covers the discharge gate (4031); and / or The arc-shaped side wall is a structure of the steepest descent curve, specifically: with the bottom end of the vertical side wall of the buffer bin (402) as the origin, the curve formed by the arc-shaped side wall satisfies: When γ∈(π,2π), y=D4·(γ-sinγ-π), z=H·[(cosγ-1)+2]; Among them, γ is an intermediate variable; y is the coordinate of the cache bin (402) in the length direction; z is the coordinate of the cache bin (402) in the height direction; D4 is the opening length at the top of the cache bin (402); H is the height of the vertical side wall of the cache bin (402).

34. A system according to claim 32 or 33, characterized in that: D4=H.

35. The system according to any one of claims 1-14, 16-18, 20-22, 24-26, 28, 30, 32-33, characterized in that: The system further comprises a negative pressure hood (12); the negative pressure hood (12) is arranged between the feeding trough (1) and the heating trough (2), and is connected to the heating hood (201); an axial flow fan (1201) is arranged in the negative pressure hood (12); pressure sensors (13) are independently arranged in the negative pressure hood (12) and the heating hood (201), and the pressure sensor (13) and the axial flow fan (1201) are linked.

36. The system according to claim 35, characterized in that: A flattener (1202) is also provided at the feeding end of the negative pressure hood (12).

37. The system according to any one of claims 1-14, 16-18, 20-22, 24-26, 28, 30, 32-33, 36, characterized in that: A feeding mechanism is also provided above the feeding trough (1).

38. The system according to claim 37, characterized in that: The feeding mechanism is a feeding crane (15) having a magnetic suction cup (14).

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