System for preparing novel furnace charge by adopting super-thick material layer

Abstract

The utility model belongs to the technical field of annular furnace smelting, and relates to a system for preparing a novel furnace material by adopting an ultra-thick material layer, which comprises an annular heating furnace and a flue gas circulation subsystem, and the annular heating furnace is sequentially divided into a forced air drying section, an air draft preheating section, a reaction section, a first-stage cooling section, a second-stage cooling section and a discharging section according to the rotating direction; the flue gas circulation subsystem comprises a drying section fan cover, a preheating section fan cover, a reaction section fan cover, a cooling section fan cover, a drying section flue gas dust collection bin and a preheating section flue gas dust collection bin installed below the air draft preheating section. The reaction section flue gas dust collecting bin is mounted below the reaction section; the cooling section flue gas dust collecting bin is mounted below the primary cooling section and the secondary cooling section; a cooling medium conveying pipeline is connected to the bottom of the cooling section flue gas dust collecting bin, the cooling section fan cover is connected with the drying section flue gas dust collecting bin, the reaction section flue gas dust collecting bin is connected with the preheating section fan cover and the reaction section fan cover, and the drying section fan cover and the preheating section flue gas dust collecting bin are connected with a chimney.

Description

Technical Field

[0001] The utility model belongs to the technical field of annular furnace smelting, and relates to a system for preparing new furnace charge by adopting an ultra-thick material layer. Background Art

[0002] In 2022, my country's overall steel production capacity will be about 1.013 billion tons. Different types of dust and slag containing iron, zinc and other metals will be produced in various processes of steel smelting. According to statistics, the converter steelmaking process produces about 15-20kg of dust and sludge per ton of steel, and the electric furnace steelmaking process produces about 10-20kg of dust and ash per ton of steel. Similarly, various types of solid wastes are also produced every year in the field of non-ferrous metal smelting, such as copper slag, nickel slag, lead-zinc slag and tailings slag. These solid wastes contain a variety of valuable elements such as Fe, Ni, Cu, Cr, Zn, Pb, Ag, etc., but most of them are in a stockpile state, occupying a large amount of land resources. According to the "National List of Hazardous Wastes (2021 Edition)", the zinc-containing dust ash produced by electric furnace steelmaking has been officially listed as HW23 hazardous waste, and HW48 hazardous waste covers almost all dust ash and smelting slag produced in the non-ferrous metal smelting and mining processes. How to effectively dispose of and utilize the above-mentioned metallurgical dust and sludge is a major issue of common concern in the steel and nonferrous metal industries.

[0003] At present, the main disposal technologies for solid waste from the metallurgical industry are pyrometallurgical (rotary kiln, rotary hearth furnace) technology and pyrometallurgical + hydrometallurgical combined technology. The advantages are that the system technology and equipment are relatively mature, while the disadvantages are that the process is long, the equipment investment cost and process energy consumption are high, and the product quality is unstable. The iron-rich material (DRI pellets or iron slag) produced is difficult to be accepted by blast furnaces or converters due to its low metallization rate and high slag content, and has low market added value.

[0004] Therefore, the market urgently needs a new system with strong raw material adaptability, large processing capacity and fast reduction speed. Utility Model Content

[0005] In view of this, the purpose of the utility model is to provide a system for preparing new charge by using ultra-thick material layer. The system is based on the ring furnace smelting process and adopts ultra-thick material layer distribution method to prepare new charge. The metallization rate of the prepared new charge reaches 70-80%, providing the market with a new system with large processing capacity, fast reduction speed, high energy utilization rate and strong raw material adaptability.

[0006] In order to achieve the above object, the utility model provides the following technical solutions:

[0007] A system for preparing new furnace charge using an ultra-thick material layer, comprising an annular heating furnace and a flue gas circulation subsystem, wherein the annular heating furnace is divided into a blast drying section, an exhaust preheating section, a reaction section, a primary cooling section, a secondary cooling section and a discharge section in sequence according to the rotation direction;

[0008] The flue gas circulation subsystem comprises a drying section hood respectively installed above the blast drying section, a preheating section hood installed above the exhaust preheating section, a reaction section hood installed above the reaction section and the primary cooling section, and a cooling section hood installed above the secondary cooling section, and a drying section flue gas dust collecting bin respectively installed below the blast drying section, a preheating section flue gas dust collecting bin installed below the exhaust preheating section, a reaction section flue gas dust collecting bin installed below the reaction section, and a cooling section flue gas dust collecting bin installed below the primary cooling section and the secondary cooling section;

[0009] A cooling medium delivery pipeline is connected to the bottom of the cooling section flue gas dust collecting bin to blow cooling medium to the primary cooling section and the secondary cooling section. The cooling section wind hood is connected to the drying section flue gas dust collecting bin through an air duct. The reaction section flue gas dust collecting bin is respectively connected to the preheating section wind hood and the reaction section wind hood through air ducts. The drying section wind hood and the preheating section flue gas dust collecting bin are connected to the chimney through air ducts to realize the flue gas circulation and external discharge of the system.

[0010] Furthermore, it also includes a sinusoidal vibrating distributor, which is sealed and docked at the feed inlet of the blast drying section in the annular heating furnace through an expansion joint.

[0011] Furthermore, sealed water tanks are provided at upper and lower ends of the left and right sides of the furnace bed in the annular heating furnace.

[0012] Furthermore, the annular heating furnace is also provided with a burner arranged in the exhaust preheating section and the reaction section, and the burner is arranged above the bed in the annular heating furnace.

[0013] Furthermore, each of the air ducts is provided with an exhaust fan.

[0014] Furthermore, a flue gas purification unit is provided on the air duct connected to the chimney, and the flue gas purification unit is arranged on a side of the exhaust fan away from the chimney.

[0015] Furthermore, the flue gas purification unit is a bag filter.

[0016] Furthermore, a bag filter for collecting dust is provided in the reaction stage flue gas dust collecting bin.

[0017] Furthermore, the position of the reaction section wind hood opposite to the primary cooling section is an inclined surface facing the reaction section and arranged obliquely upward, so that the cooling medium blown from bottom to top in the primary cooling section continues to be blown toward the reaction section after passing through the charge, so as to achieve the effect of guiding the airflow.

[0018] The beneficial effects of the utility model are:

[0019] The utility model provides a system for preparing new furnace charge with an ultra-thick material layer, which maximizes the thickness of the material layer while ensuring the sealing and reducibility of the system, realizes rapid reduction by convection heat transfer, and ensures the metallization rate of the product in the cooling section, effectively avoiding the problem of secondary oxidation, and provides a multi-stage circulating air supply system to meet the heating requirements of the system. By setting multiple process sections of drying, exhaust, heating, reduction and cooling in conjunction with the multi-stage circulating air supply system, it is ensured that the ultra-thick material layer can achieve efficient heat exchange and rapid reduction under flow conditions, and a new furnace charge metallization rate of 70-80% is obtained.

[0020] The system has strong ductility and can effectively cover multiple fields such as direct reduction of metallurgical solid hazardous waste, pyrolysis of organic solid waste, and sintering pre-reduction of tailings slag. It is a new system with large processing capacity, fast reduction speed, high energy utilization rate, and strong raw material adaptability.

[0021] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and research, or can be taught from the practice of the present invention to some extent. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be described in detail below in conjunction with the accompanying drawings, in which:

[0023] Figure 1 It is a structural schematic diagram of a system for preparing a new type of furnace charge using an ultra-thick material layer;

[0024] Figure 2 It is a schematic diagram of the partitions of the annular heating furnace;

[0025] Figure 3 This is a schematic diagram of the structure of the sealed water tank in the annular heating furnace.

[0026] Figure numerals: 1-sinusoidal vibrating distributor, 2-flue gas dust collecting bin, 3-burner, 4-sealed water tank, 5-exhaust fan, 6-flue gas purification unit, 7-chimney, 8-annular heating furnace, 81-air drying section, 82-exhaust preheating section, 83-reaction section, 84-primary cooling section, 85-secondary cooling section, 86-discharging section, 9-wind hood. DETAILED DESCRIPTION

[0027] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0028] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present utility model. In order to better illustrate the embodiments of the present utility model, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0029] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "back" and the like indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] See also Figure 1 to Figure 3 , is a system for the above-mentioned method of preparing new furnace charges using ultra-thick material layers, the system for preparing new furnace charges using ultra-thick material layers comprises an annular heating furnace 8, a sinusoidal vibrating distributor 1 and a flue gas circulation subsystem, the sinusoidal vibrating distributor 1 is sealed and docked at the inlet of the annular heating furnace 8 through an expansion joint, and sealed water tanks 4 are provided at the upper and lower ends of both sides of the furnace bed in the annular heating furnace 8 to ensure the sealing of the annular heating furnace 8.

[0031] The annular heating furnace 8 is divided into a blast drying section 81, an exhaust preheating section 82, a reaction section 83, a primary cooling section 84, a secondary cooling section 85 and a discharging section 86 in sequence according to the rotation direction, and the sinusoidal vibrating distributor 1 is arranged on a side of the blast drying section 81 away from the exhaust preheating section 82;

[0032] The flue gas circulation subsystem includes a hood 9 and a flue gas dust collecting bin 2 and a duct for connecting the hood 9, the flue gas dust collecting bin 2 and the chimney 7. The hood 9 includes a drying section hood installed above the blast drying section 81, a preheating section hood installed above the exhaust preheating section 82, a reaction section hood installed above the reaction section 83 and the primary cooling section 84, and a cooling section hood installed above the secondary cooling section 85.

[0033] The flue gas dust collecting bin 2 includes a drying section flue gas dust collecting bin installed below the blast drying section 81, a preheating section flue gas dust collecting bin installed below the exhaust preheating section 82, a reaction section flue gas dust collecting bin installed below the reaction section 83, and a cooling section flue gas dust collecting bin installed below the primary cooling section 84 and the secondary cooling section 85.

[0034] Specifically, the wind hood 9 and the flue gas dust collecting bin 2 are both used to collect cold air after heat exchange at the corresponding installation position (it should be noted that in the cooling section, the wind hood is used to collect hot air after heat exchange), or to blow hot air to the corresponding installation position (it should be noted that in the cooling section, the flue gas dust collecting bin 2 is used to blow cooling medium).

[0035] Preferably, the reaction section wind hood is installed above the reaction section and the primary cooling section, and the position of the reaction section wind hood directly opposite the primary cooling section is an inclined surface facing the reaction section and arranged obliquely upward, so that the cooling medium blown from bottom to top in the primary cooling section continues to be blown toward the reaction section after passing through the charge, thereby achieving the effect of guiding the airflow.

[0036] Preferably, the fume dust collecting bin 2 is funnel-shaped to collect or blow gas, and the drying section hood, preheating section hood and cooling section hood are inverted funnel-shaped to collect or blow gas.

[0037] A nitrogen delivery pipeline is connected to the bottom of the cooling section flue gas dust collecting bin to blow nitrogen to the primary cooling section 84 and the secondary cooling section 85 to achieve the purpose of cooling the furnace charge. The cooling section hood is connected to the drying section flue gas dust collecting bin through an air duct, and the reaction section flue gas dust collecting bin is respectively connected to the preheating section hood and the reaction section hood through an air duct. The drying section hood and the preheating section flue gas dust collecting bin are connected to the chimney 7 through an air duct.

[0038] The annular heating furnace 8 is also provided with burners 3 arranged at the exhaust preheating section 82 and the reaction section 83 to allow the circulating flue gas to be fully burned in the furnace body.

[0039] Specifically, the reaction section 83 includes a heating section and a reduction section connected in sequence, and heats the charge by exhausting air; an exhaust fan 5 is provided on each of the air ducts, and a flue gas purification unit 6 is provided on the air duct connected to the chimney 7.

[0040] Preferably, the flue gas purification unit 6 can be specifically configured as a bag dust collector; the temperature of the charge in the reaction section 83 is relatively high, which will generate a large amount of dust, and the reaction section flue gas dust collecting bin has a dust removal function (a cyclone dust collector or a bag dust collector can be used) to prevent the dust from damaging the exhaust fan installed on the corresponding air duct.

[0041] A method for preparing new furnace charge based on the system of the utility model, the specific steps are as follows:

[0042] A. Add the mixed and formed internal carbon pellets into the annular furnace and run them to the drying section in the furnace for blast drying to remove moisture from the materials and obtain dried furnace charge;

[0043] B. The dried charge moves with the furnace body to the preheating section, that is, during the exhaust process, the hot air quickly passes through the material layer to complete the preheating of the material layer, and the preheated charge is obtained. The cold air after heat exchange is discharged from the chimney together with the cold air from the drying section;

[0044] C. The preheated charge enters the reaction section for heating and reduction in sequence, and is cooled in the primary cooling section. In the heating section and the reduction section, the hot air passes through the material layer during the exhaust process to complete heat transfer and reduction. The high-temperature reducing gas generated in the process is returned to the preheating section and the reaction section through the flue gas circulation to burn and heat. When it reaches the primary cooling section, the cooling medium is blown into the metallized pellets to complete the cooling, and oxygen is provided for combustion in the reaction section.

[0045] D. The charge that has completed the reduction reaction moves to the secondary cooling section, where secondary cooling is achieved by continuously blowing cooling medium through the material layer. The hot air after heat exchange returns to the drying section for drying.

[0046] Furthermore, the material layer thickness in the annular furnace in step A is controlled to be 30-50 cm, the furnace bed adopts a porous heat-resistant grate plate, and the product metallized pellets are used as the bottom material with a thickness controlled to be 8-10 cm to ensure the air permeability and heat exchange efficiency of the whole process.

[0047] Furthermore, the heating temperature of the blast drying section (drying chamber) described in step A is about 180° C. (20-180° C.), and the moisture content of the material is reduced to <2% by blast heating.

[0048] Furthermore, the exhaust preheating section (preheating chamber) described in step B is provided with a burner inside to fully burn the CO in the circulating flue gas, and then the material layer is preheated by exhaust, and the preheating temperature is about 420°C (180°C~420°C).

[0049] Furthermore, the pellets in step C are preheated and then enter the reaction section, where heat supply and reduction are completed, wherein the heating section matches the burner to rapidly heat the pellets in the material layer to 800°C-1100°C under the condition of exhaust flow, and impurities such as alkali metals and halogens are removed during the process, and the reduction section continues to heat to 1100-1200°C under this condition to complete the reduction reaction and increase the metallization rate of the pellets to 70-80%, until the reaction is completed and enters the primary cooling section, where the cooling medium is blown through the material layer to achieve rapid cooling to below 300°C.

[0050] Furthermore, in step C, to ensure that there is no leakage of gas in the furnace, a water sealing structure is used above and below the furnace bed.

[0051] Furthermore, in step D, the metallized pellets can be further cooled to below 100° C. by providing a secondary cooling section to continuously blow cooling medium into the material layer.

[0052] Preferably, the cooling medium is cold air or an inert gas, and the inert gas can specifically be nitrogen.

[0053] Based on the method of preparing new furnace charge by using ultra-thick material layer proposed by the utility model, the method involves a wide range of fields and has strong technical ductility. It can effectively cover multiple fields such as direct reduction of metallurgical solid hazardous waste, pyrolysis of organic solid waste, sintering pre-reduction of tailings slag, etc. It has technical characteristics such as large processing capacity, fast reduction speed, high energy utilization rate, and strong raw material adaptability.

[0054] Example 1

[0055] Step 1: Feed the carbon-containing pellets of blast furnace ash into the annular heating furnace 8 through the distribution port (sinusoidal vibrating distributor 1), the material layer thickness is about 30 cm, the bottom material is DRI metal balls, the thickness is about 8 cm, and the upper and lower parts of the furnace body are sealed with sealed water tanks 4 to form a water-sealed structure to ensure that the furnace gas does not overflow;

[0056] Step 2: The charge is first transferred to the blast drying section 81 with the furnace body to be dried to less than 1% moisture at 180°C. After drying, the cold air is discharged from the chimney 7, and the hot rice in the blast drying section 81 comes from the hot air discharged from the secondary cooling section 85;

[0057] Step 3: After drying, the furnace charge enters the exhaust preheating section 82, and the high-temperature flue gas is quickly extracted from the material layer from top to bottom, completing efficient heat exchange, and further heating the furnace charge to about 400°C. The extracted flue gas is discharged from the chimney 7, and the high-temperature flue gas comes from the flue gas discharged from the reaction section;

[0058] Step 4: When the charge runs to the reaction section 83, it passes through the heating section and the reduction section successively to raise the temperature to about 1200°C. During the exhaust process, impurities are removed and the reduction reaction is completed between the material layers. The reducing flue gas generated is circulated to the heating section and the exhaust preheating section 82 to be burned by the burner 3 for heat.

[0059] Step 5: The reacted charge continuously passes through the primary cooling section 84 and the secondary cooling section 85, and heat exchange is completed under the condition of continuous nitrogen blowing. The pellet temperature can be reduced to below 80°C and discharged from the discharging section 86, and the hot air after heat exchange in the secondary cooling section 85 is blown back to the blast drying section 81 to dry the charge.

[0060] The metallized pellets of the product in this implementation case were sampled and analyzed, and the total iron content was about 56%, the metallization rate was about 74%, the residual carbon content of the pellets was <2%, and the impurity content of K, Na, F, Cl, etc. was <1%.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A system for preparing new furnace charge using ultra-thick material layer, characterized in that: It includes an annular heating furnace and a flue gas circulation subsystem, and the annular heating furnace is divided into a blast drying section, an exhaust preheating section, a reaction section, a primary cooling section, a secondary cooling section and a discharging section in sequence according to the rotation direction; The flue gas circulation subsystem comprises a drying section hood respectively installed above the blast drying section, a preheating section hood installed above the exhaust preheating section, a reaction section hood installed above the reaction section and the primary cooling section, and a cooling section hood installed above the secondary cooling section, and a drying section flue gas dust collecting bin respectively installed below the blast drying section, a preheating section flue gas dust collecting bin installed below the exhaust preheating section, a reaction section flue gas dust collecting bin installed below the reaction section, and a cooling section flue gas dust collecting bin installed below the primary cooling section and the secondary cooling section; A cooling medium delivery pipeline is connected to the bottom of the cooling section flue gas dust collecting bin to blow cooling medium to the primary cooling section and the secondary cooling section. The cooling section wind hood is connected to the drying section flue gas dust collecting bin through an air duct. The reaction section flue gas dust collecting bin is respectively connected to the preheating section wind hood and the reaction section wind hood through air ducts. The drying section wind hood and the preheating section flue gas dust collecting bin are connected to the chimney through air ducts to realize the flue gas circulation and external discharge of the system.

2. The system for preparing new furnace charge using ultra-thick material layer according to claim 1, characterized in that: It also includes a sinusoidal vibrating distributor, which is sealed and docked at the feed inlet of the blast drying section in the annular heating furnace through an expansion joint.

3. The system for preparing new furnace charge using ultra-thick material layer according to claim 1 is characterized in that: In the annular heating furnace, sealed water tanks are provided at the upper and lower ends of the left and right sides of the furnace bed.

4. The system for preparing new furnace charge using ultra-thick material layer according to claim 1, characterized in that: The annular heating furnace is also provided with a burner arranged in the exhaust preheating section and the reaction section, and the burner is arranged above the bed in the annular heating furnace.

5. The system for preparing new furnace charge using ultra-thick material layer according to claim 1, characterized in that: Each of the air ducts is provided with an exhaust fan.

6. The system for preparing new furnace charge using ultra-thick material layer according to claim 5, characterized in that: A flue gas purification unit is provided on the air duct connected to the chimney, and the flue gas purification unit is arranged on a side of the exhaust fan away from the chimney.

7. The system for preparing new furnace charge using ultra-thick material layer according to claim 6, characterized in that: The flue gas purification unit is a bag filter.

8. The system for preparing new furnace charge using ultra-thick material layer according to claim 1, characterized in that: A bag filter for collecting dust is provided in the reaction stage flue gas dust collecting bin.

9. The system for preparing new furnace charge using ultra-thick material layer according to claim 1, characterized in that: The position of the reaction section wind cover opposite to the primary cooling section is an inclined surface facing the reaction section and arranged obliquely upward, so that the cooling medium blown from bottom to top in the primary cooling section continues to be blown toward the reaction section after passing through the charge, so as to achieve the effect of guiding the airflow.

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