A low-carbon sintered carbon oxide emission reduction system and method based on electric heating technology

Abstract

The application belongs to the technical field of steel metallurgy, and particularly relates to a low-carbon sintering CO x The system comprises a sintering trolley (1), a plurality of heating elements (2), a lug (3), a wire (4), a power supply (5), and a temperature detection device (6). The plurality of heating elements (2) are respectively inserted from the bottom of the sintering trolley (1), each heating element (2) is provided with a lug (3) at the bottom of two end heads, the lugs (3) are connected in pairs by the wire (4), and the power supply (5) is connected to the circuit formed by the lugs (3) and the wire (4). The temperature detection device (6) is used for monitoring the temperature of the sinter. The method and the system can provide heat for the lower part of the sintering material layer by the electric heating mode, can realize the segregation distribution of the solid fuel, can reduce the usage and the ratio of the solid fuel in the lower part of the sintering material layer, and can effectively reduce CO and CO2 generated by the combustion of the solid fuel.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a low-carbon sintering CO2 method based on electric heating technology. x Emission reduction systems and methods. Background Technology

[0002] Currently, regarding the implementation of ultra-low emission control targets in the steel industry: under the condition of a baseline oxygen volume fraction of 16%, the hourly average emission concentrations of particulate matter, sulfur dioxide, and nitrogen oxides in the flue gas from the sintering machine head and pellet roasting should not exceed 10, 35, and 50 mg / m³, respectively. 3 .

[0003] Sintering, as a crucial process in integrated steel production lines, is characterized by high energy consumption and high pollution. Statistics show that sintering accounts for 11%–16% of the total energy consumption in the steel industry, with CO volume fraction in sintering flue gas ranging from 0.5% to 2.0%, and CO2 emissions accounting for 12%–14% of total emissions from steel enterprises. It also contains SO2 and NO... X Particulate matter and particulate matter emissions account for 40%~60%, 50%~55%, and 15%~20% of the total emissions from steel enterprises, respectively. Therefore, achieving low-carbon emissions in the sintering process is imperative.

[0004] In traditional sintering processes, coal gas is used for ignition, and solid fuels such as coke powder or pulverized coal are added to the raw materials to provide the heat required for the solidification reaction. Coal gas and solid fuels such as coke powder or pulverized coal are fossil fuels, and a large amount of CO2 is generated during the sintering process. x Furthermore, as the sintering reaction proceeds, the gravity of the sintering bed intensifies its impact on the permeability of each sintering zone, especially the combustion-melting zone. With the continued sintering process, the self-heating effect becomes increasingly significant, leading to a gradual increase in the temperature and liquid phase content of the combustion zone. The load pressure of the upper sintering bed further exacerbates the impact on the combustion-melting zone, fully compressing the ore and liquid phases, hindering gas flow, and drastically worsening the permeability of the bed, resulting in a decline in the quality of the sintered ore. Improving the permeability of the bed and the complete combustion of coke powder are crucial for reducing fuel consumption and CO2 emissions in the sintering process. x Emissions and improving the quality of sintered ore are of paramount importance.

[0005] Chinese patent CN202111063097.7 provides a low-carbon sintering method based on high-temperature hot air, comprising the following steps: 1. Dividing the annular cooler (7) into a high-temperature section, a medium-high-temperature section, a medium-low-temperature section, and a low-temperature section from the feed end to the discharge end; 2. Setting up a hot air furnace (4) between the annular cooler and the high-temperature hot air hood (3), extracting high-temperature hot air from the high-temperature section and medium-high-temperature hot air from the medium-high-temperature section, mixing the high-temperature hot air and medium-high-temperature hot air into circulating hot air and conveying it to the hot air furnace; 3. The circulating hot air is heated by biomass fuel in the hot air furnace to form high-temperature circulating hot air; 4. Conveying the high-temperature circulating hot air into the high-temperature hot air hood, so that the high-temperature circulating hot air enters the sintering machine material layer for high-temperature hot air sintering of the sintering mixture. This method can reduce the consumption of fossil solid fuels in the sintering mixture and reduce carbon dioxide emissions by performing high-temperature hot air sintering on the sintering machine material surface through high-temperature circulating hot air. However, high-temperature hot air sintering requires an additional high-temperature heat source, resulting in high energy consumption during the sintering process.

[0006] Chinese invention patent application CN201811331593.4 discloses an iron ore sintering apparatus and method based on fuel stratification and flue gas recirculation, using biomass char to replace coke. This iron ore sintering apparatus includes a sintering machine body, a mixing tank, an ignition furnace, a holding furnace, a wind box, a mixed flue gas recirculation pipe, a mixed flue gas recirculation fan, a mixed flue gas dust removal device, a sintered ore cooling waste gas pipe, a recirculating flue gas pipe, a sintering trolley, a large flue, a large flue dust removal and desulfurization device, a large flue fan, a chimney, and a sintering furnace. This apparatus and method can replace coke with biomass char, achieving a reduction in fossil fuel consumption, utilization of flue gas waste heat, enrichment of SO2 in the flue gas, and a reduction in flue gas emissions. This method requires extracting most of the high-temperature sintering flue gas for circulation, which will reduce the flue gas temperature in the main sintering flue, thereby reducing the service life of the main flue electrostatic precipitator system. Furthermore, it cannot guarantee the efficient and low-consumption operation of the desulfurization and denitrification system and will lead to emission pollution risks.

[0007] Chinese patent application 201510305331.0 discloses a flue gas recirculation type pre-reduction sintering process and apparatus. The method includes: 1) mixing iron concentrate and coal fuel and then pelletizing to obtain carbon-containing pellets; 2) batching iron ore powder, flux and coal fuel powder, and then adding water in a primary mixer to obtain a sintering mixture; 3) mixing the carbon-containing pellets, the sintering mixture and additional coal fuel powder in a secondary mixer to obtain a pre-reduction sintering mixture, wherein the ratio (wt) of the sintering mixture, carbon-containing pellets and additional coal fuel powder is 50-70:28-48:1-5; 4) arranging the pre-reduction sintering mixture on a sintering trolley for flue gas recirculation type pre-reduction sintering; and 5) cooling the sintered pre-reduction sinter under oxygen-free conditions. The fuel used in this invention patent is still primary energy - coke. The fuel is evenly distributed throughout the sintering bed. Due to the heat storage characteristics of the sintering bed, the upper bed is underburned, the lower bed is overburned, and the return rate is too high, which has adverse effects on the yield and quality of sinter.

[0008] However, electric heating technology can directly convert electrical energy into heat energy, avoiding energy loss during fuel combustion. This results in a relatively high energy conversion rate and reduces energy waste. The advantages of electric heating technology have led to its widespread application in various industrial sectors. Therefore, there is an urgent need for a low-carbon sintering system and method based on electric heating technology. Summary of the Invention

[0009] To address the shortcomings and problems of existing technologies, this invention provides a low-carbon CO2 sintering method based on electric heating technology. x The emission reduction system and method provide heat to the lower part of the sintering material layer through electric heating, which can realize the segregation distribution of solid fuel, reduce the amount and proportion of solid fuel in the lower part of the sintering material layer, and effectively reduce the CO and CO2 generated by the combustion of solid fuel. In addition, the inserted heating element can also provide a certain support for the upper material layer, effectively reduce the upper load of the combustion melting zone of the sintering material layer, and improve the permeability of the lower material layer.

[0010] To achieve the above-mentioned technical objectives, the main technical solutions adopted by the present invention include:

[0011] On the one hand, a sintering low-carbon CO2 based on electric heating technology is provided. x The emission reduction system, where X=1 or 2, mainly includes a sintering trolley 1, multiple heating elements 2, connecting pieces 3, wires 4, power supply 5, and a temperature detection device 6.

[0012] In this invention, multiple heating elements 2 are inserted from the bottom of the sintering trolley 1. Each heating element 2 has two connecting pieces 3 installed at its bottom ends. The connecting pieces 3 are connected adjacent to each other by wires 4, and the wires 4 are connected to a power supply 5. That is, the power supply 5 is connected to the circuit where the connecting pieces 3 and the wires 4 are connected to the power supply. The temperature detection device 6 is used to monitor the temperature of the sintered ore.

[0013] Preferably, the heating elements 2 are arranged in a row, and the rows can be arbitrarily arranged, either in series or in parallel; the heating element material 2 is one or more of zirconium oxide, nickel-chromium alloy, and iron-chromium-aluminum alloy, for example, Cr 20 Ni 80 Cr 30 Ni 70 Cr 15 Ni 60 wait.

[0014] Furthermore, the lateral spacing of the heating elements 2 is 600 mm to 700 mm, the longitudinal spacing of the heating elements 2 is 100 mm to 400 mm, the number of heating elements 2 is approximately 12 to 24, and the total heating power is approximately 1200 kW to 2400 kW.

[0015] Furthermore, the heating element 2 is inverted U-shaped, with a height of approximately 300 mm to 400 mm, a diameter of approximately 10 mm to 25 mm, and a bending radius of approximately 30 mm to 100 mm.

[0016] Furthermore, a high-temperature wear-resistant coating can be applied to the surface of the heating element 2. The coating material is nano-ceramic, tungsten carbide alloy, or polymeric ceramic. This high-temperature wear-resistant coating is a material that is commercially available in the art.

[0017] On the other hand, a sintering low-carbon CO2 based on electric heating technology is provided. x Emission reduction methods mainly include the following steps:

[0018] (1) After the sintering mixture is placed on the sintering trolley 1, the power supply 5 is turned on to heat the heating element 2 and ignite for sintering.

[0019] (2) The temperature of the sinter is monitored by the temperature detection device 6. If the temperature of the sinter exceeds the maximum value T of the appropriate range... max This indicates that the sintering process is overheating. At this time, the power supply 5 is turned off to stop heating the heating element 2.

[0020] (3) If the temperature of the sinter is within a suitable range (T) min ~T max If the sintering process is not stable, continue heating as usual.

[0021] (4) If the temperature of the sinter is below the minimum value T of the appropriate range min This indicates that the sintering process is too cold. In this case, it is necessary to increase the heating power of the heating element to raise the temperature to a suitable range.

[0022] As described above, preferably, the sintering mixture is laid out in layers.

[0023] Furthermore, the amount of carbon outside the heating zone is approximately 3.0 wt% to 4.0 wt%, and the amount of carbon in the heating zone is approximately 2.0 wt% to 3.0 wt%.

[0024] As described above, preferably, the suitable temperature range for the sinter is approximately 1100℃~1400℃.

[0025] The beneficial effects of this invention are:

[0026] (1) Place the heating element in CO x In the lower part of the high-concentration feed layer (and the middle and later sections of sintering), heat is supplied to the sintering feed layer via electric heating. This electric heating effectively supplements the heat demand at the bottom of the feed layer during combustion, reducing the amount of solid fuel used. By reducing the proportion of solid fuel, CO2 levels can be lowered. x This reduces the amount of pollutants generated and decreases atmospheric pollution. Furthermore, electric heating offers precise temperature control and stable heating characteristics, enabling accurate control of the sintering process. This helps improve the stability and consistency of the sintering process, reducing product quality fluctuations caused by unstable combustion or uneven heat distribution.

[0027] (2) The inserted heating element can provide some support for the upper sintering layer, reduce the compressive force generated by the gravity of the upper material surface on the molten zone during the sintering process, thereby improving the permeability of the lower part of the sintering layer, increasing the local oxygen concentration, which helps to promote the complete combustion of solid fuel and reduce CO in the sintering flue gas. x The emission of pollutants increases the vertical sintering speed. Attached Figure Description

[0028] Figure 1 CO2 from sintering flue gas x Emission characteristic curve;

[0029] Figure 2 This is a front view of a sintering low-carbon emission reduction system based on electric heating technology according to the present invention.

[0030] Figure 3 This is a side view of a sintering low-carbon emission reduction system based on electric heating technology according to the present invention.

[0031] Figure 4This is a top view of a sintering low-carbon emission reduction system based on electric heating technology according to the present invention.

[0032] Figure label:

[0033] 1-Sintering trolley, 2-Heating element, 3-Connecting piece, 4-Wire, 5-Power supply, 6-Temperature detection device. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] According to an embodiment of the present invention, a sintering low-carbon CO2 based on electric heating technology is provided. x The emission reduction system includes a sintering trolley 1, a heating element 2, a connecting piece 3, a wire 4, a power supply 5, and a temperature detection device 6.

[0036] The heating elements 2 are arranged in a row, and the rows can be arbitrarily arranged, either in series or in parallel; the heating element material 2 is one or more of zirconium oxide, nickel-chromium alloy, and iron-chromium-aluminum alloy, for example, Cr 20 Ni 80 Cr 30 Ni 70 Cr 15 Ni 60 The heating elements 2 have a lateral spacing of 600 mm to 700 mm and a longitudinal spacing of 100 mm to 400 mm. The number of heating elements 2 is approximately 12 to 24, and the total heating power is approximately 1200 kW to 2400 kW. The heating elements 2 are inverted U-shaped, with a height of approximately 300 mm to 400 mm, a diameter of approximately 10 mm to 25 mm, and a bending radius of approximately 30 mm to 100 mm. A high-temperature wear-resistant coating can be applied to the surface of the heating elements 2; the coating material can be nano-ceramics, tungsten carbide alloy, or polymer ceramics. The heating elements 2 are inserted from the bottom of the sintering trolley 1. A connecting piece 3 is installed at the bottom of the heating element 2, and the connecting piece is connected via a wire 4. The wire 4 is connected to a power supply 5. The temperature detection device 6 is installed on the sintering trolley 1 to monitor the temperature of the sintered ore.

[0037] This invention provides a sintering low-carbon CO2 system. x The emission reduction methods specifically include the following steps:

[0038] (1) After the sintering mixture is placed on the sintering trolley 1, the power supply 5 is turned on to heat the heating element 2 and ignite for sintering.

[0039] (2) The temperature of the sinter is monitored by the temperature detection device 6. If the temperature of the sinter exceeds the maximum value T of the appropriate range... max This indicates that the sintering process is overheating. At this time, the power supply 5 is turned off to stop heating the heating element 2.

[0040] (3) If the temperature of the sinter is within a suitable range (T) min ~T max If the sintering process is not stable, continue heating as usual.

[0041] (4) If the temperature of the sinter is below the minimum value T of the appropriate range min This indicates that the sintering process is too cold. In this case, it is necessary to increase the heating power of heating element 2 to raise the temperature to a suitable range.

[0042] The appropriate temperature range for the sintered ore is approximately 1100℃ to 1400℃.

[0043] Example 1

[0044] The sintering of low-carbon CO2 using the aforementioned electric heating technology x The emission reduction system and method include a sintering trolley with dimensions of 4.0 m × 1.5 m × 0.8 m and an average density of approximately 1600 kg / m³ for the sintering raw materials. 3 The average specific heat capacity is approximately 970 J / (kg·℃), the lateral spacing of the heating elements is set to 650 mm, the longitudinal spacing of the heating elements is set to 300 mm, the number of heating elements is set to 15, the average total heating power is set to 1500 kW, the diameter of the heating elements is 20 mm, the bending radius is 50 mm, the height is 400 mm, the carbon content in the upper part of the electric heating area is 3.8 wt%, the average combustion efficiency of solid fuel is approximately 88%, and the sintering time is approximately 35 min.

[0045] Solid fuel combustion produces CO x The reaction equation is shown below:

[0046] C + O₂ = CO₂ Δ H =-33.41×10 6 J / kg

[0047] C + 0.5O₂ = CO Δ H =-9.8×10 6 J / kg

[0048] Based on equivalent heat conversion, the carbon content in the electrically heated zone is approximately 2.46 wt%, a reduction of 1.34 wt%. Solid fuel consumption is approximately 31.3 kg / t, a decrease of 6.7 kg / t. The CO2 content during sintering is... x Emissions were reduced by approximately 17.6%, and the vertical sintering speed was approximately 23.62 mm / min, an increase of 3.32%.

[0049] Example 2

[0050] Referring to the method and steps in Example 1, except that the total heating power of the heating element is set to 2400kW, after equivalent heat conversion, the carbon content of the sinter in the electrically heated zone is approximately 1.69%, a reduction of 2.11%, and the solid fuel consumption is approximately 27.6kg / t, a reduction of 10.4kg / t. The CO2 content during the sintering process... x Emissions were reduced by approximately 28.2%, and the vertical sintering speed was 24.13 mm / min, an increase of 5.56%.

[0051] Example 3

[0052] Referring to the method and steps in Example 1, except that the number of heating elements is set to 24, the lateral spacing of the heating elements is set to 550 mm, the longitudinal spacing of the heating elements is set to 220 mm, the average total heating power is set to 2160 kW, and the height of the heating elements is 300 mm. Based on equivalent heat conversion, the carbon content of the sinter in the electrically heated zone is approximately 2.38%, a reduction of 1.42%, and the solid fuel consumption is approximately 30.9 kg / t, a reduction of 7.3 kg / t. The CO2 content during the sintering process... x Emissions were reduced by approximately 19.1%, and the vertical sintering speed was 23.85 mm / min, an increase of 4.34%.

[0053] Comparative Example 1

[0054] This comparative example uses a conventional sintering method for sintering, and differs from Example 1 in that it does not include the heating element 2, the connecting piece 3, the wire 4, or the power supply 5.

[0055] When using the system and method of this comparative example for iron ore sintering, no layered batching method was adopted, therefore no CO2 was generated. x The emission reduction effect is that solid fuel consumption is approximately 38.0 kg / t, and the vertical sintering speed is approximately 22.86 mm / min.

[0056] As can be seen from the above embodiments and comparative examples, the present invention can reduce solid fuel consumption and CO2 emissions during the sintering process by using electric heating. x It can reduce emissions and achieve low-carbon emission reduction in sintering; it can also improve the air permeability of the lower part of the sintering material layer and shorten the sintering time.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-carbon sintering CO2 method based on electric heating technology x The emission reduction system is characterized by, The system includes a sintering trolley (1), multiple heating elements (2), connecting pieces (3), wires (4), power supply (5), and temperature detection device (6). The plurality of heating elements (2) are inserted from the bottom of the sintering trolley (1), and each heating element (2) has a connecting piece (3) installed at the two ends of its bottom. The connecting pieces (3) are connected in pairs through wires (4), and the power supply (5) is connected to the circuit where the connecting pieces (3) and the wires (4) are located. The temperature detection device (6) is used to monitor the temperature of the sinter. The heating element (2) is made of one or more of zirconium oxide, nickel-chromium alloy and iron-chromium-aluminum alloy; The lateral spacing of the heating elements (2) is 600 mm to 700 mm, the longitudinal spacing of the heating elements (2) is 100 mm to 400 mm, the number of heating elements (2) is 12 to 24, and the total heating power is 1200 kW to 2400 kW. The heating element (2) is inverted U-shaped, with a height of 300 mm to 400 mm, a thickness of 10 mm to 25 mm, and a bending radius of 30 mm to 100 mm.

2. The low-carbon sintering CO2 based on electric heating technology as described in claim 1 x The emission reduction system is characterized by, The multiple heating elements (2) are arranged in a row, and the temperature detection device (6) is installed on the sintering trolley (1).

3. The low-carbon sintering CO based on electric heating technology as described in claim 1 x The emission reduction system is characterized by, The heating element (2) is coated with a high-temperature wear-resistant coating. The coating material includes nano-ceramics, tungsten carbide alloys, or polymer ceramics.

4. A low-carbon sintered CO2 emission reduction system based on any one of claims 1-3 x Emission reduction methods include the following steps: (1) After the sintering mixture is placed on the sintering trolley (1), the power supply (5) is turned on to heat the heating element (2) and ignite for sintering; (2) The temperature of the sinter is monitored by a temperature detection device (6).

5. The low-carbon sintering CO as described in claim 4 x The emission reduction method is characterized by, If the temperature of the sinter exceeds the maximum value T within the appropriate range max At this time, turn off the power (5) to stop heating the heating element (2); If the temperature of the sinter is within a suitable range T min ~T max If so, continue heating normally; If the temperature of the sinter is below the minimum value T of the appropriate range min Increase the heating power of the heating element to raise the temperature to a suitable range.

6. The low-carbon sintering CO as described in claim 4 x The emission reduction method is characterized by, The sintering mixture is distributed in layers, with 3.0wt%~4.0wt% carbon content outside the heating zone and 2.0wt%~3.0wt% carbon content in the heating zone.

7. The low-carbon sintering CO as described in claim 4 x The emission reduction method is characterized by, The suitable temperature range for the sintered ore is 1100℃~1400℃.

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