Vertical furnace system and method for synergistically treating iron-containing solid waste based on fuel and electric energy

Abstract

The present invention provides a vertical furnace system and method for coordinating the treatment of iron-containing solid waste based on fuel and electric energy, wherein the system includes a gas pipe and a vertical smelting furnace, the vertical smelting furnace includes a fore furnace and a smelting furnace body, the smelting furnace body has a furnace body, a furnace belly and a furnace bottom arranged in sequence from top to bottom; a feeding port for adding materials to the furnace cavity of the smelting furnace body is provided on the upper side of the furnace body; an air enclosure pipe is provided around the furnace belly outside the furnace belly, and a plurality of tuyere connected to the inner cavity of the furnace belly is provided on the air enclosure pipe, plasma generators are installed in at least two tuyere, at least two tuyere are connected to the gas pipe, and the tuyere where the plasma generator is installed and the tuyere connected to the gas pipe are different tuyere; the furnace bottom is connected to the fore furnace. The power and furnace condition of the smelting furnace can be flexibly adjusted during the furnace opening and smelting process, and the system's requirements for the material structure in the furnace are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgy and chemical industry, and in particular relates to a vertical furnace system and method for co-processing iron-containing solid waste based on fuel and electric energy. Background Art

[0002] Modern human society produces a large amount of scrap steel resources every year. In order to utilize scrap steel resources, they are often recycled after smelting in converters or electric furnaces. However, scrap steel from automobiles and home appliances usually contains alloys such as zinc and nickel, and often has paint or other organic coatings or dust on the surface. During the smelting process, the decomposition of organic matter in this type of scrap steel will produce toxic gas that pollutes the environment and damages human health. In addition, this type of scrap steel is light in weight and has a large specific surface area. Even if the briquettes are loaded into converters or electric furnaces for smelting, the yield of metallic iron is low. Therefore, the recycling process of this type of inferior scrap steel resources still needs to be improved.

[0003] In addition, the global steel industry produces tens of millions of tons of various dust, mud, slag and other by-products containing metallic iron every year. From the perspective of chemical composition, these by-products contain iron, carbon, nickel, chromium, zinc, lead and other elements, and are mineral resources with huge reserves. At present, the processes used by steel companies to process such by-products of steel metallurgical processes mainly include rotary hearth furnace, OxyCup and DK processes.

[0004] The rotary hearth furnace process is the most widely used direct reduction treatment device for iron-containing dust. This process directly reduces the dust through mixing → batching → molding, and removes harmful elements such as lead and zinc to obtain metallized pellet products. However, the metallized pellet products produced by it have low iron grade and large slag volume, and the steelmaking process cannot be carried out in large quantities. When used as ironmaking raw materials, it affects the blast furnace charging operation and the permeability of the material column. This process is not suitable for treating dust with high zinc content and low total iron content, and cannot treat steel slag and other iron-containing solid wastes with larger particle sizes, and the investment cost is relatively high.

[0005] The DK process and OxyCup process belong to the category of molten reduction method, which can recycle iron-containing dust and steel slag resources produced by traditional steel metallurgical processes. The molten iron products can be used for converter steelmaking after pretreatment. However, the DK process uses a sintering agglomeration process, which has the disadvantages of high pollution and high energy consumption. The smelting furnace of the Oxycup process is a typical vertical furnace reactor. In order to ensure the air permeability in the furnace, the agglomeration requirements of this process are relatively high, requiring the use of large pieces of metallurgical coke and large consumption. The equipment has a short operating life and a large maintenance workload. In the treatment of iron-containing solid waste, the Oxycup process cannot be widely promoted. At present, only Taigang has introduced this process from Germany in China to treat stainless steel dust briquette. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In order to solve the above-mentioned problems in the prior art, the first object of the present invention is to provide a vertical furnace system for the coordinated treatment of iron-containing solid waste based on fuel and electric energy, which can flexibly adjust the smelting furnace power and furnace conditions during the furnace opening and smelting process, thereby reducing the system's requirements on the material structure in the furnace.

[0008] The second object of the present invention is to provide a method for the coordinated treatment of iron-containing solid waste based on fuel and electric energy, which realizes the comprehensive treatment of scrap steel and by-products of steel metallurgical processes, and has good air permeability of the material column in the furnace, low coke consumption and low cost.

[0009] (II) Technical solution

[0010] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0011] In the first aspect, the present invention provides a vertical furnace system for synergistically treating iron-containing solid waste based on fuel and electric energy, comprising a gas pipe and a vertical smelting furnace, the vertical smelting furnace comprising a forefurnace and a smelting furnace body, the smelting furnace body comprising a furnace body, a furnace belly and a furnace bottom arranged in sequence from top to bottom; a feeding port for adding materials to the furnace cavity of the smelting furnace body is provided on the upper side of the furnace body; an air surrounding pipe is arranged around the furnace belly outside the furnace belly, a plurality of tuyere connected to the inner cavity of the furnace belly is provided on the air surrounding pipe, plasma generators are installed in at least two tuyere, at least two tuyere are connected to the gas pipe, and the tuyere where the plasma generator is installed and the tuyere connected to the gas pipe are different tuyere; the furnace bottom is connected to the forefurnace.

[0012] Optionally, the system for vertically processing iron-containing solid waste based on the coordinated use of fuel and electricity also includes a dust hood, a dust delivery pipe, a bag dust collector, an induced draft fan, and a lifting and feeding device for transporting materials from the bottom of the furnace to the feeding port and feeding the furnace cavity; the dust hood outside the smelting furnace is arranged above the feeding port corresponding to the feeding port, the top of the dust hood is connected to the inlet of the dust delivery pipe, the outlet of the dust delivery pipe is connected to the air inlet of the bag dust collector through a wind valve, and the air outlet of the bag dust collector is connected to the air inlet of the induced draft fan.

[0013] Optionally, the system for vertically processing iron-containing solid waste based on the coordinated use of fuel and electricity also includes a smoke delivery pipe, a cyclone dust collector, an air preheater, a blower and an induced draft fan; a first flue gas duct and an air duct that are not connected to each other are provided in the air preheater, the air inlet of the air preheater is connected to the air outlet of the blower, and the air outlet of the air preheater is connected to the air surrounding pipe; the upper part of the furnace body is connected to the inlet of the smoke delivery pipe, the outlet of the smoke delivery pipe is connected to the inlet of the cyclone dust collector, the outlet of the cyclone dust collector is connected to the smoke inlet of the air preheater, and the smoke outlet of the air heat exchanger is connected to the air inlet of the induced draft fan; the lower part of the cyclone dust collector is provided with an ash discharger for discharging smoke.

[0014] Optionally, the system for vertically processing iron-containing solid waste based on the coordinated use of fuel and electricity also includes a primary heat exchanger; a second flue gas duct and a water duct that are not connected to each other are provided in the primary heat exchanger, and the water duct is a water supply branch in the tap water network; the flue gas inlet of the primary heat exchanger is connected to the outlet of the cyclone dust collector through a first flue gas switching valve, the flue gas inlet of the primary heat exchanger is connected to the flue gas outlet of the air heat exchanger through a second flue gas switching valve, and the flue gas outlet of the primary heat exchanger is connected to the air inlet of the induced draft fan; an ash discharger for discharging smoke is provided at the lower part of the primary heat exchanger.

[0015] Optionally, the flue gas outlet of the primary heat exchanger is connected to the air inlet of the induced draft fan through the denitrification device, the secondary heat exchanger, the bag filter and the desulfurization device in sequence; the air outlet of the induced draft fan is connected to the chimney.

[0016] Optionally, the system for vertically processing iron-containing solid waste based on the coordinated use of fuel and electricity also includes a cold air duct; the secondary heat exchanger and the bag dust collector are connected by a connecting pipe; a temperature sensor is provided on the connecting pipe, and the cold air duct is connected to the cold air inlet of the connecting pipe through a cold air valve; the temperature sensor and the cold air inlet are arranged in sequence along the fluid flow direction in the connecting pipe.

[0017] Optionally, the air surrounding pipe is provided with a first group of tuyere, a second group of tuyere and a third group of tuyere arranged in sequence from top to bottom, each group of tuyere contains multiple tuyere, and the multiple tuyere in each group of tuyere are evenly distributed around the furnace belly; at least two tuyere in the third group of tuyere are installed with plasma generators, at least two tuyere in the second group of tuyere are connected to the gas pipe, and the remaining tuyere only blows air.

[0018] In a second aspect, the present invention provides a method for treating iron-containing solid waste based on the synergistic treatment of fuel and electric energy, and treating iron-containing solid waste based on the system for treating iron-containing solid waste based on the synergistic treatment of fuel and electric energy vertically as described above, comprising the following steps:

[0019] S1. Set the pile weight ratio to 0-2t / m 3 The thin scrap steel is packaged and crushed into scrap steel briquettes, the outer dimensions of the scrap steel briquettes are greater than 100×100×100mm and less than 200×200×200mm; according to binary basicity = 0.7-1.1, one or more of steel slag magnetic separation iron material, blast furnace dust mud, converter sludge, electric furnace dust removal ash, sintering dust mud, pellet dust mud and iron oxide scale are mixed, and hot pressed to obtain hot pressed briquettes; coke blocks with outer dimensions greater than 100×100×100mm and less than 200×200×200mm are selected;

[0020] S2, according to the feeding cycle of adding scrap steel briquettes, hot briquettes and coke briquettes in sequence, feeding materials into the furnace cavity through the feeding port for multiple feeding cycles to form multiple groups of stacked material units in the furnace cavity, each group of material units comprising a scrap steel layer, a hot briquette layer and a coke layer arranged in sequence from bottom to top;

[0021] S3. During the smelting process, materials are added into the furnace chamber through the feeding port according to the feeding cycle based on the smelting downward speed of the material; and the plasma generator is started and stopped according to the working conditions, and the power and furnace conditions of the smelting furnace are adjusted to meet the requirements.

[0022] As an improvement of the method of the present invention, in one feeding cycle, the weight ratio of scrap steel briquettes, hot pressed briquettes and coke blocks is (6-8.5):(0.9-3):(0.6-1); the volume ratio of the scrap steel layer, hot pressed briquettes layer and coke layer in a group of material units is (6-8):(1-2):(1-2), and the thickness of the scrap steel layer in a group of material units is 400-500 mm.

[0023] As an improvement of the method of the present invention, during the smelting process, the amount of gas blown from the tuyere is 10 to 18 Nm per ton of material. 3 ; The air volume blown from the tuyere is 600~700Nm per ton of material 3 The temperature of the air blown out of the tuyere is 400-450℃.

[0024] (III) Beneficial effects

[0025] The beneficial effects of the present invention are:

[0026] 1. The vertical furnace system for the coordinated treatment of iron-containing solid waste based on fuel and electric energy provided by the present invention sprays gas and preheated air through the tuyere, and the combustion of gas and preheated air provides the main heat to the main body of the smelting furnace. By installing a plasma generator at the tuyere, the tuyere can spray high-temperature gas to assist in heating the main body of the smelting furnace; specifically, during the opening of the smelting furnace, when the opening temperature is abnormal due to insufficient addition of heat source materials (such as coke), the plasma generator can flexibly add heat to reduce the amount of coke; during the smelting process, the plasma generator can be started and stopped according to the working conditions, provide part of the heat, and adjust the power and furnace conditions of the smelting furnace to meet the requirements; during the smelting process, the plasma generator works to provide heat and reduce the consumption of energy materials (such as coke and gas). It can be seen that the system proposed by the present invention can flexibly adjust the power and furnace conditions of the smelting furnace during the opening and smelting process, and reduce the system's requirements for the material structure in the furnace.

[0027] 2. The method for treating iron-containing solid waste based on the synergistic treatment of fuel and electric energy proposed by the present invention is to cyclically add materials in a specific order of feeding, so that the material column in the furnace is layered, and the scrap steel layer serves as the skeleton of the material column in the furnace to ensure the air permeability of the material column in the furnace. During the smelting process, the combustion of gas and preheated air provides the main heat to the main body of the smelting furnace to continuously smelt the iron-containing solid waste, and the smelting forms molten iron above 1400°C. The molten iron flows into the front furnace through the molten iron flow channel. The front furnace is provided with a molten iron outlet and a slag outlet. The slag outlet is opened regularly to discharge slag, and the iron outlet is opened to discharge iron, and the molten iron flows into the molten iron tank; the plasma generator is started and stopped according to the working conditions, provides part of the heat, and adjusts the power and furnace conditions of the smelting furnace to meet the requirements; the combustion of coke provides part of the heat, and also serves as a reducing agent and a scrap steel carburizing agent. Therefore, the method proposed by the present invention realizes the comprehensive treatment of scrap steel and by-products of the iron and steel metallurgical process, the air permeability of the material column in the furnace is good, the amount of coke used is small, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a vertical furnace system for co-processing iron-containing solid waste based on fuel and electric energy according to a specific embodiment of the present invention;

[0029] Figure 2 It is a schematic flow diagram of a method for co-processing iron-containing solid waste based on fuel and electric energy according to a specific embodiment of the present invention.

[0030] [Description of Reference Numerals]

[0031] 1: Gas pipe;

[0032] 2: front furnace;

[0033] 3: Melting furnace body;

[0034] 31: feed port; 32: air surrounding pipe; 33: plasma generator;

[0035] 41: dust hood; 42: dust delivery pipe; 43: bag filter; 44: induced draft fan; 45: lifting and feeding device; 46: air valve;

[0036] 51: cooling water inlet; 52: cooling water outlet;

[0037] 61: smoke delivery pipe; 62: cyclone dust collector; 63: air preheater; 64: blower; 66: ash discharger;

[0038] 71: primary heat exchanger; 72: first flue gas switching valve; 73: second flue gas switching valve; 74: tap water network;

[0039] 81: Denitrification device; 82: Secondary heat exchanger; 83: Desulfurization device; 84: Chimney;

[0040] 91: Temperature sensor; 92: Cold air valve. DETAILED DESCRIPTION

[0041] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0042] like Figure 1 As shown, the present invention provides a vertical furnace system for synergistically treating iron-containing solid waste based on fuel and electric energy, comprising a gas pipe 1 and a vertical smelting furnace, the vertical smelting furnace comprising a fore furnace 2 and a smelting furnace body 3, the smelting furnace body 3 having a furnace body, a furnace belly and a furnace bottom arranged in sequence from top to bottom; a feeding port 31 for adding materials to the furnace cavity of the smelting furnace body 3 is provided on the upper side of the furnace body; an air surrounding pipe 32 is arranged around the furnace belly outside the furnace belly, and a plurality of air jets (commonly referred to as tuyere) connected to the inner cavity of the furnace belly are provided on the air surrounding pipe 32, plasma generators 33 are installed in at least two tuyere, at least two tuyere are connected to the gas pipe 1, and the tuyere where the plasma generator 33 is installed and the tuyere connected to the gas pipe 1 are different tuyere; the furnace bottom is connected to the fore furnace 2.

[0043] With such arrangement, gas and preheated air are sprayed through the tuyere, and the combustion of gas and preheated air provides the main heat to the smelting furnace body 3. By installing a plasma generator 33 at the tuyere, the tuyere can spray out high-temperature gas to assist in heating the smelting furnace body 3; specifically, during the smelting furnace opening process, when the furnace opening temperature is abnormal due to insufficient addition of heat source materials (such as coke), heat can be flexibly added through the plasma generator 33 to reduce the amount of coke used; during the smelting process, the plasma generator can be started and stopped according to the working conditions, provide part of the heat, and adjust the power and furnace conditions of the smelting furnace to meet the requirements; during the smelting process, the plasma generator works to provide heat and reduce the consumption of fuel materials (such as coke and gas). The energy provided by the plasma generator accounts for about 10% of the energy required by the vertical furnace system. It can be seen that the system proposed by the present invention can flexibly adjust the power and furnace conditions of the smelting furnace during the furnace opening and smelting process, and reduce the system's requirements for the material structure in the furnace.

[0044] Preferably, the vertical furnace system for treating iron-containing solid waste based on fuel and electric energy also includes a dust hood 41, a dust delivery pipe 42, a bag filter 43, an induced draft fan 44, and a lifting and feeding device 45 for conveying materials from the furnace bottom to the feeding port 31 and feeding the furnace cavity; the dust hood 41 outside the smelting furnace is arranged above the feeding port 31 corresponding to the feeding port 31, the top of the dust hood 41 is connected to the inlet of the dust delivery pipe 42, the outlet of the dust delivery pipe 42 is connected to the air inlet of the bag filter 43 through the air valve 46, and the air outlet of the bag filter 43 is connected to the air inlet of the induced draft fan 44. The air valve 46 is opened before the feeding starts to remove the smoke generated during the feeding process, and the air valve 46 is closed after the feeding is completed.

[0045] Preferably, the furnace belly and the furnace bottom adopt water-cooled linings, and the circulating cooling water of the water-cooled linings enters from the cooling water inlet 51, and the circulating cooling water flows out from the cooling water outlet 52. The circulating cooling lining effectively ensures the production life of the smelting furnace body 3.

[0046] Preferably, the vertical furnace system for co-processing iron-containing solid waste based on fuel and electric energy further includes a smoke delivery pipe 61, a cyclone dust collector 62, an air preheater 63, a blower 64 and an induced draft fan 44; the air preheater 63 is provided with a first smoke pipe and an air pipe which are not connected to each other, the air inlet of the air preheater 63 is connected to the air outlet of the blower 64, and the air outlet of the air preheater 63 is connected to the air surrounding pipe 32; the upper part of the furnace body is connected to the inlet of the smoke delivery pipe 61, the outlet of the smoke delivery pipe 61 is connected to the inlet of the cyclone dust collector 62, the outlet of the cyclone dust collector 62 is connected to the smoke inlet of the air preheater 63, and the smoke outlet of the air heat exchanger is connected to the air inlet of the induced draft fan 44; the lower part of the cyclone dust collector 62 is provided with an ash discharger 66 for discharging smoke. The cyclone dust collector 62 collects smoke and discharges it through the ash discharger, and its zinc-rich smoke can be used as a raw material for zinc production and reused for a second time. The air preheater 63 can heat the air in the air duct into preheated air at 400-450° C., thereby realizing the utilization of waste heat of the flue gas.

[0047] Preferably, the vertical furnace system for co-processing iron-containing solid waste based on fuel and electric energy further includes a primary heat exchanger 71; a second flue gas pipe and a water pipe which are not connected to each other are arranged in the primary heat exchanger 71, and the water pipe is a water delivery branch pipe in the tap water network 74; the flue gas inlet of the primary heat exchanger 71 is connected to the outlet of the cyclone dust collector 62 through the first flue gas switching valve 72, the flue gas inlet of the primary heat exchanger 71 is connected to the flue gas outlet of the air heat exchanger through the second flue gas switching valve 73, and the flue gas outlet of the primary heat exchanger 71 is connected to the air inlet of the induced draft fan 44; an ash discharger for discharging smoke is arranged at the lower part of the primary heat exchanger 71. The first flue gas switching valve 72 and the second flue gas switching valve 73 can be flexibly switched according to the production situation and the equipment maintenance situation; through the primary heat exchanger 71, the secondary utilization of flue gas is realized to heat tap water.

[0048] Preferably, the flue gas outlet of the primary heat exchanger 71 is connected to the air inlet of the induced draft fan 44 through the denitrification device 81, the secondary heat exchanger 82, the bag filter 43 and the desulfurization device 83 in sequence; the air outlet of the induced draft fan 44 is connected to the chimney 84. The denitrification device 81 removes nitrogen oxides from the flue gas, the secondary heat exchanger 82 further recovers the flue gas residual energy and can reduce the temperature of the flue gas entering the bag filter 43. The flue gas after cooling enters the bag filter 43 to collect dust, so that the suspended particulate matter in the flue gas meets the emission standard, and the flue gas after dust removal enters the desulfurization device 83 to remove sulfur dioxide from the flue gas.

[0049] Preferably, the vertical furnace system for co-processing iron-containing solid waste based on fuel and electric energy also includes a cold air pipe; the secondary heat exchanger 82 is connected to the bag filter 43 through a connecting pipe; a temperature sensor 91 is provided on the connecting pipe, and the cold air pipe is connected to the cold air inlet of the connecting pipe through a cold air valve 92; the temperature sensor 91 and the cold air inlet are arranged in sequence along the flow direction of the fluid in the connecting pipe. In this way, during the production process, when the flue gas temperature before the bag filter 43 is higher than 120°C, the cold air valve 92 can be opened to cool down.

[0050] Further preferably, the air surrounding pipe 32 is provided with a first group of tuyere, a second group of tuyere and a third group of tuyere arranged in sequence from top to bottom, each group of tuyere contains a plurality of tuyere, and the plurality of tuyere in each group of tuyere are evenly distributed around the furnace belly; at least two tuyere in the third group of tuyere are equipped with a plasma generator 33, at least two tuyere in the second group of tuyere are connected to the gas pipe 1, and the remaining tuyere only sprays air. Specifically, each group of tuyere contains 8 tuyere.

[0051] Since the shaft furnace system proposed by the present invention for treating iron-containing solid wastes based on the synergistic use of fuel and electric energy has low structural requirements for the materials in the furnace, the present invention also proposes a method for treating iron-containing solid wastes (scrap steel and by-products of steelmaking process) based on the above system. Among them, the by-products of steelmaking process include magnetic separation of slag iron, blast furnace dust, converter sludge, electric furnace dust, sintering dust, pellet dust and iron oxide scale.

[0052] like Figure 2 As shown, the method for treating iron-containing solid waste based on the synergistic effect of fuel and electric energy proposed in the present invention comprises the following steps:

[0053] S1. Set the pile weight ratio to 0-2t / m 3 The thin scrap steel (such as household appliance scrap steel) is packaged and crushed into scrap steel briquettes, the outer dimensions of the scrap steel briquettes are greater than 100×100×100mm and less than 200×200×200mm; according to the slag composition design, one or more of steel slag magnetic separation iron materials, blast furnace dust mud, converter sludge, electric furnace dust removal ash, sintering dust mud, pellet dust mud and iron oxide scale are mixed, and hot pressed to make hot pressed briquettes; coke blocks with outer dimensions greater than 100×100×100mm and less than 200×200×200mm are selected.

[0054] Among them, the slag composition design refers to binary basicity = 0.7 ~ 1.1, and the basicity takes the upper limit when the sulfur load of the raw material is high.

[0055] Preferably, the TFe content in the magnetically separated iron material of steel slag is not less than 85%; and the C content in the coke is not less than 85%.

[0056] Optionally, S1 further includes: selecting a certain amount of limestone (flux) with a particle size of 30 mm to 50 mm according to the raw material composition to adjust the slag basicity.

[0057] S2. According to the feeding cycle of adding scrap steel briquettes, hot briquettes and coke briquettes in sequence, feeding materials into the furnace cavity is repeated multiple times through the feeding port to form multiple groups of stacked material units in the furnace cavity, and each group of material units includes a scrap steel layer, a hot briquette layer and a coke layer arranged in sequence from bottom to top.

[0058] Preferably, in one feeding cycle, the weight ratio of scrap steel briquettes, hot pressed briquettes and coke blocks is (6-8.5):(0.9-3):(0.6-1); the volume ratio of the scrap steel layer, hot pressed briquettes layer and coke layer in a group of material units is (6-8):(1-2):(1-2), and the thickness of the scrap steel layer in a group of material units is 400-500 mm.

[0059] Specifically, the material is added into the furnace cavity through the feed port for multiple feeding cycles to a level of 0.6 to 1.2 m below the lower edge of the feed port.

[0060] S3. During the smelting process, materials are added into the furnace chamber through the feeding port according to the material smelting downward speed and the feeding cycle.

[0061] Preferably, during the smelting process, the amount of gas blown from the tuyere is 10 to 18 Nm per ton of material. 3 ; The air volume blown from the tuyere is 600~700Nm per ton of material 3 The temperature of the air blown out of the tuyere is 400-450℃.

[0062] The method for treating iron-containing solid waste based on the synergistic treatment of fuel and electric energy proposed by the present invention cyclically feeds in a specific feeding order, so that the material column in the furnace is layered, and the scrap steel layer serves as the skeleton of the material column in the furnace to ensure the air permeability of the material column in the furnace. During the smelting process, the combustion of gas and preheated air provides the main heat to the main body of the smelting furnace to continuously smelt the iron-containing solid waste, and the smelting forms molten iron above 1400°C. The molten iron flows into the front furnace through the molten iron flow channel. The front furnace is provided with a molten iron outlet and a slag outlet. The slag outlet is opened regularly to discharge slag, and the iron outlet is opened to discharge iron, and the molten iron flows into the molten iron tank; the plasma generator is started and stopped according to the working conditions, provides part of the heat, and adjusts the power and furnace conditions of the smelting furnace to meet the requirements; the combustion of coke provides part of the heat, and also serves as a reducing agent and a scrap steel carburizing agent. Therefore, the method proposed by the present invention realizes the comprehensive treatment of scrap steel and by-products of the iron and steel metallurgical process, the air permeability of the material column in the furnace is good, the amount of coke used is small, and the cost is low.

[0063] Example 1

[0064] A method for treating iron-containing solid waste based on the synergistic treatment of iron-containing solid waste by fuel and electric energy, using the vertical furnace system for treating iron-containing solid waste based on the synergistic treatment of iron-containing solid waste by fuel and electric energy to treat iron-containing solid waste, wherein two air ports in the third group of air ports are provided with 30kW plasma generators, comprising the following steps:

[0065] S1. Set the bulk weight ratio to 1.4t / m 3 The light and thin scrap steel is packaged and crushed into scrap steel briquettes, the outer dimensions of the scrap steel briquettes are greater than 100×100×100mm and less than 200×200×200mm; hot pressed briquettes are obtained by hot pressing mixed particle steel (steel slag magnetic separation iron material) and blast furnace dust; coke blocks with outer dimensions of 100×100×100mm and less than 200×200×200mm are selected; limestone with a particle size of 30-50mm is selected as flux.

[0066] The TFe content in the particle steel is not less than 85%; the C content in the coke is not less than 85%.

[0067] The composition of blast furnace dust is:

[0068]

[0069] S2. According to the feeding cycle of adding scrap steel briquettes, hot briquettes, coke briquettes and flux in sequence, the feeding cycle is repeated multiple times to feed into the furnace chamber to 0.6m below the lower edge of the feeding port, so as to form multiple groups of stacked material units in the furnace chamber, each group of material units comprising a scrap steel layer, a hot briquette layer, a coke layer and a flux layer (limestone) arranged in sequence from bottom to top.

[0070] Among them, in one feeding cycle, the weight ratio of scrap steel briquettes, hot pressed briquettes, coke blocks and flux is 768kg:340kg:93kg:10kg (that is, the weight ratio is 64:27:8:1); the volume ratio of the scrap steel layer, hot pressed briquettes layer and coke layer in a group of material units is 64:18:18, and the thickness of the scrap steel layer in a group of material units is 400mm.

[0071] S3. During the smelting process, materials are added into the furnace chamber through the feeding port according to the feeding cycle based on the smelting downward speed of the material; and the plasma generator is started and stopped according to the working conditions, and the power and furnace conditions of the smelting furnace are adjusted to meet the requirements.

[0072] During the smelting process, the amount of gas blown from the tuyere is 11Nm per ton of material. 3 ; The air volume blown from the tuyere is 630Nm per ton of material 3 The temperature of the air blown out of the tuyere is 400-450℃.

[0073] According to the test, in the above method, the replacement rate of gas chemical energy and electric energy for coke chemical energy is about 25%. The coke usage of the OxyCup furnace for treating iron-containing solid waste is about 287kg coke / t molten iron product. Compared with the OxyCup furnace, the coke usage of this embodiment is reduced by about 70% and the carbon emission is reduced by about 30%.

[0074] Example 2

[0075] The main difference between this embodiment and embodiment 1 is that:

[0076] A method for treating iron-containing solid waste based on the synergistic treatment of fuel and electric energy, using the vertical furnace system for treating iron-containing solid waste based on the synergistic treatment of fuel and electric energy to treat iron-containing solid waste, wherein four tuyere in the third group of tuyere are equipped with a 30kW plasma generator, comprising the following steps:

[0077] S1. Set the bulk weight ratio to 1.4t / m 3 The thin scrap steel is packaged and crushed into scrap steel briquettes, the size of which is greater than 100×100×100mm and less than 200×200×200mm; the particle steel (slag magnetic iron material) and blast furnace dust are mixed and hot pressed to obtain hot pressed briquettes; the coke briquettes with the size greater than 100×100×100mm and less than 200×200×200mm are selected; the limestone with the particle size of 30 to 50mm is selected. Among them, the TFe content in the particle steel is not less than 85%; the C content of the coke is not less than 85%.

[0078] The composition of blast furnace dust is:

[0079]

[0080] S2. According to the feeding cycle of adding scrap steel briquettes, hot briquettes and coke briquettes in sequence, the feeding cycle is repeated multiple times to feed into the furnace chamber to 0.8m below the lower edge of the feeding port, so as to form multiple groups of stacked material units in the furnace chamber, each group of material units comprising a scrap steel layer, a hot briquette layer, a coke layer and a flux layer (limestone) arranged in sequence from bottom to top.

[0081] Among them, in one feeding cycle, the weight ratio of scrap steel briquettes, hot pressed briquettes, coke blocks and flux is 925kg:100kg:65kg:10kg (that is, the weight ratio is 84:9:6:1); the volume ratio of the scrap steel layer, hot pressed briquettes layer and coke layer in a group of material units is 74:16:10, and the thickness of the scrap steel layer in a group of material units is 500mm.

[0082] S3. During the smelting process, materials are added into the furnace chamber through the feeding port according to the feeding cycle based on the smelting downward speed of the material; and the plasma generator is started and stopped according to the working conditions, and the power and furnace conditions of the smelting furnace are adjusted to meet the requirements.

[0083] During the smelting process, the amount of gas blown from the tuyere is 11Nm per ton of material. 3 ; The air volume blown from the tuyere is 600Nm per ton of material 3 The temperature of the air blown out of the tuyere is 400-450℃.

[0084] According to the test, in the above method, the replacement rate of gas chemical energy and electric energy for coke chemical energy is about 45%. The coke usage of OxyCup furnace for treating iron-containing solid waste is about 287kg coke / t molten iron. Compared with OxyCup furnace, the coke usage of this embodiment is reduced by about 80% and the carbon emission is reduced by about 30%.

[0085] It should be understood that the above description of the specific embodiments of the present invention is only for illustrating the technical route and features of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but the present invention is not limited to the above specific implementation methods. Any changes or modifications made within the scope of the claims of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating iron-containing solid waste based on the synergistic effect of fuel and electricity, characterized in that: A vertical furnace system for treating iron-containing solid waste based on the synergistic treatment of iron-containing solid waste by fuel and electric energy is used to treat iron-containing solid waste. The system comprises a gas pipe (1) and a vertical smelting furnace. The vertical smelting furnace comprises a forehearth and a smelting furnace body (3). The smelting furnace body (3) comprises a furnace body, a furnace belly and a furnace bottom arranged in sequence from top to bottom. A feeding port (31) for adding materials into the furnace cavity of the smelting furnace body (3) is provided on the upper side of the furnace body. An air enclosure pipe (32) is provided outside the furnace belly and around the furnace belly. A plurality of tuyere connected to the inner cavity of the furnace belly are provided on the air enclosure pipe (32). Plasma generators (33) are installed in at least two of the tuyere. At least two of the tuyere are connected to the gas pipe (1). The tuyere on which the plasma generator (33) is installed and the tuyere connected to the gas pipe (1) are different tuyere. The furnace bottom is connected to the forehearth. The air surrounding pipe (32) is provided with a first group of tuyere, a second group of tuyere and a third group of tuyere arranged in sequence from top to bottom, each group of tuyere contains a plurality of tuyere, and the plurality of tuyere in each group of tuyere are evenly distributed around the furnace belly; at least two tuyere in the third group of tuyere are equipped with a plasma generator (33), at least two tuyere in the second group of tuyere are connected to the gas pipe (1), and the remaining tuyere only sprays air; The method comprises the following steps: S1. Set the pile weight ratio to 0-2t / m 3 The thin scrap steel is packaged and crushed into scrap steel briquettes, the outer dimensions of the scrap steel briquettes are greater than 100×100×100mm and less than 200×200×200mm; according to binary basicity = 0.7-1.1, one or more of steel slag magnetic separation iron material, blast furnace dust mud, converter sludge, electric furnace dust removal ash, sintering dust mud, pellet dust mud and iron oxide scale are mixed, and hot pressed to obtain hot pressed briquettes; coke blocks with outer dimensions greater than 100×100×100mm and less than 200×200×200mm are selected; S2, according to the feeding cycle of adding scrap steel briquettes, hot briquettes and coke briquettes in sequence, feeding materials into the furnace cavity through the feeding port for multiple feeding cycles to form multiple groups of stacked material units in the furnace cavity, each group of material units comprising a scrap steel layer, a hot briquette layer and a coke layer arranged in sequence from bottom to top; S3. During the smelting process, materials are added into the furnace chamber through the feeding port according to the feeding cycle according to the smelting downward speed of the materials; and the plasma generator is started and stopped according to the working conditions, and the power and furnace conditions of the smelting furnace are adjusted to meet the requirements; In one feeding cycle, the weight ratio of scrap steel briquettes, hot pressed briquettes and coke blocks is (6-8.5):(0.9-3):(0.6-1); the volume ratio of scrap steel layer, hot pressed briquettes layer and coke layer in a group of material units is (6-8):(1-2):(1-2), and the thickness of the scrap steel layer in a group of material units is 400-500 mm.

2. The method for treating iron-containing solid waste based on fuel and electric energy according to claim 1, characterized in that: During the smelting process, the amount of gas blown from the tuyere is 10-18Nm per ton of material. 3 ; The air volume blown from the tuyere is 600~700Nm per ton of material 3 The temperature of the air blown out of the tuyere is 400-450℃.

3. The method for treating iron-containing solid waste based on fuel and electric energy according to claim 1, characterized in that: The system also includes a dust removal hood (41), a dust delivery pipe (42), a bag dust collector (43), an induced draft fan (44), and a lifting and feeding device (45) for conveying materials from the furnace bottom to the feeding port (31) and feeding materials into the furnace chamber; A dust hood (41) is arranged above the feeding port (31) on the outside of the smelting furnace, corresponding to the feeding port (31); the top of the dust hood (41) is connected to the inlet of the dust delivery pipe (42); the outlet of the dust delivery pipe (42) is connected to the air inlet of the bag dust collector (43) through an air valve; and the air outlet of the bag dust collector (43) is connected to the air inlet of the induced draft fan (44).

4. The method for treating iron-containing solid waste based on fuel and electric energy according to claim 1, characterized in that: The system also includes a smoke delivery pipe (61), a cyclone dust collector (62), an air preheater (63), a blower (64) and an induced draft fan (44); The air preheater (63) is provided with a first flue gas duct and an air duct which are not connected to each other. The air inlet of the air preheater (63) is connected to the air outlet of the blower (64), and the air outlet of the air preheater (63) is connected to the air surrounding pipe (32); the upper part of the furnace body is connected to the inlet of the smoke delivery pipe (61), the outlet of the smoke delivery pipe (61) is connected to the inlet of the cyclone dust collector (62), the outlet of the cyclone dust collector (62) is connected to the flue gas inlet of the air preheater (63), and the flue gas outlet of the air heat exchanger is connected to the air inlet of the induced draft fan (44); the lower part of the cyclone dust collector (62) is provided with an ash discharger for discharging smoke.

5. The method for treating iron-containing solid waste based on fuel and electric energy according to claim 4, characterized in that: The system also includes a primary heat exchanger (71); A second flue gas pipe and a water pipe which are not connected to each other are arranged in the first-stage heat exchanger (71); the water pipe is a water supply branch pipe in the tap water network (74); the flue gas inlet of the first-stage heat exchanger (71) is connected to the outlet of the cyclone dust collector (62) through a first flue gas switching valve (72); the flue gas inlet of the first-stage heat exchanger (71) is connected to the flue gas outlet of the air heat exchanger through a second flue gas switching valve (73); the flue gas outlet of the first-stage heat exchanger (71) is connected to the air inlet of the induced draft fan (44); and an ash discharger for discharging smoke is arranged at the lower part of the first-stage heat exchanger (71).

6. The method for treating iron-containing solid waste based on fuel and electric energy according to claim 5, characterized in that: The flue gas outlet of the primary heat exchanger (71) is connected to the air inlet of the induced draft fan (44) through the denitration device (81), the secondary heat exchanger (82), the bag filter (43) and the desulfurization device (83) in sequence; the air outlet of the induced draft fan (44) is connected to the chimney (84).

7. The method for treating iron-containing solid waste based on fuel and electric energy according to claim 5, characterized in that: The system also includes a cold air pipe; the secondary heat exchanger (82) and the bag dust collector (43) are connected via a connecting pipe; A temperature sensor (91) is provided on the connecting pipe, and the cold air pipe is connected to the cold air inlet of the connecting pipe through a cold air valve (92); the temperature sensor (91) and the cold air inlet are arranged in sequence along the flow direction of the fluid in the connecting pipe.

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