Method for ignition by adopting biomass fuel in iron ore sintering

Abstract

A biomass fuel ignition method for iron ore sintering is characterized in that biomass fuel is sprayed above the material level of a sintering mixture to form a sintering material layer and a biomass layer from bottom to top, and the biomass layer is ignited after material distribution is completed; wherein the thicknesses of the biomass layers are distributed in a stepped mode in the width direction of the sintering pallet. Biomass fuel is adopted for ignition, clean and green zero-carbon ignition is achieved, and compared with the prior art, carbon emission is obviously reduced; meanwhile, the characteristics of low ignition point, high thermal chemical reaction activity, high combustion speed and high combustion intensity of biomass fuel are utilized, and the biomass layers are arranged on the surface of the sintering material layer in a stepped manner, so that the adverse effect of the fringe effect on the sintered ore is effectively relieved, and the overall performance of the sintered ore is greatly improved.

Description

Technical Field

[0001] The invention relates to a sintering ignition method, in particular to an iron ore sintering ignition method using biomass fuel, belonging to the technical field of sintering. Background Art

[0002] In the sintering process, ignition is to ignite the coke powder in the material surface mixture of the sintering machine trolley through high-temperature flame or high-temperature atmosphere, so that it forms a high-temperature, uniform red-hot combustion zone. Under the negative pressure of the exhaust of the lower large flue, the combustion zone will slowly move downward, gradually completing the sintering behavior of the sintering mixture of each height unit. Finally, when the combustion zone moves down to the bottom of the material layer, the sintering of the material layer carried by the trolley is completed. At this time, the trolley has also moved to the tail of the sintering machine, unloaded the sintered finished ore from the tail, and went to the next cooling link. Ignition is the core and key link of the sintering machine. Whether the ignition is uniform and whether the formed combustion zone is qualified determines the quality indicators, energy consumption indicators and operating rate indicators of the entire sintering process.

[0003] The existing ignition process of iron ore sintering mostly adopts traditional gas ignition, that is, after the sintering trolley is filled with sintering mixture and enters the ignition section of the ignition and insulation furnace, it is baked by the high-temperature flame formed by the gas ignition burner in the ignition section, and the coke powder in the sintering mixture is gradually ignited to form a red-hot combustion zone, and then enters the insulation section of the ignition and insulation furnace, and is baked by the medium-temperature flame formed by the insulation burner in the insulation section. At present, the ignition of iron ore sintering and even the subsequent sintering process have the following major defects:

[0004] 1. High carbon emissions: On the one hand, since coal gas is used for ignition, carbon-containing combustibles such as CO and CH4 in the coal gas will generate CO2 after combustion, which will be drawn into the flue and discharged, making the carbon emission index of the sintering process high; on the other hand, since solid fossil fuels such as coke powder or anthracite are added to the sintering mixture, these solid fossil fuels will burn to generate CO2 during the ignition and sintering process, further increasing carbon emissions;

[0005] 2. Due to the edge effect, uniform sintering speed cannot be achieved in the width direction of the trolley, and the production and quality of the sintered ore cannot be guaranteed: since the air inlet resistance on both sides of the sintering trolley is smaller than that in the middle area, the vertical sintering speed of the edge sintering material is significantly higher than that in the middle area; and the large particles of sintering material in the sintering mixture are easy to roll down to the sides of the sintering trolley during the distribution, resulting in the original air permeability of the edge sintering material being better than that of the sintering material in the middle area, which in turn accelerates the vertical sintering speed of the sintering material at the edge, making the sintering rate on both sides of the sintering cross section too fast, the sintering end point is delayed, and even raw materials appear in the center of the trolley, affecting the sintering ore production and the quality of the finished ore. Moreover, the excessively fast vertical sintering speed at the edge can easily lead to incomplete reaction of the sintering material during the sintering process, too fast cooling speed, imperfect crystallization, and increased glass content of the edge sintering ore, which ultimately affects the quality of the sintered ore. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention proposes a method for igniting iron ore sintering using biomass fuel. In this method, the biomass fuel is sprayed on the surface of the sintering mixture so that the sintering surface is covered with a layer of biomass fuel, wherein the thickness of the biomass fuel is arranged in a stepped manner with a thick middle and a thin edge in the width direction of the sintering trolley, and after the material is laid, the biomass fuel is ignited to start sintering. The technical solution of arranging biomass layers in steps on the surface of the sintering material layer for ignition according to the present invention can effectively utilize the characteristics of biomass fuel such as low ignition point, high thermochemical reaction activity, fast combustion speed and high combustion intensity, so that the middle position of the trolley with a thick biomass layer can burn more quickly on the sintering material surface to form a red-hot combustion zone than the edge position of the trolley with a thin biomass layer, thereby making the combustion speed of the middle position of the trolley faster than that of the edge position of the trolley. During the sintering process, the edge effect will cause the vertical sintering speed of the sintering material at the edge of the trolley to be higher than that at the middle position. Finally, the two will offset each other and achieve uniform sintering speed at the edge and middle positions of the trolley. That is, the present invention can effectively alleviate the adverse effects of the edge effect on the sintered ore, comprehensively improve the yield and quality of the sintered ore, and enhance the overall performance of the sintered ore.

[0007] Moreover, since the CO2 released by biomass fuel during combustion is derived from the CO2 absorbed during its growth, biomass fuel has the characteristic of net zero emission of CO2. The present invention uses biomass fuel for ignition, realizes clean and green zero-carbon ignition, and significantly reduces carbon emissions compared with the prior art. In addition, since biomass fuel has a low ignition point and a fast combustion speed, electric heat ignition or hot air ignition can be used to ignite biomass fuel. Compared with the traditional gas ignition method, carbon emissions are further reduced, while reducing ignition energy consumption, and achieving low-carbon ignition sintering.

[0008] According to an embodiment of the present invention, a method for sintering iron ore using biomass fuel ignition is provided.

[0009] A method of igniting iron ore sintering using biomass fuel, spraying biomass fuel on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top, and igniting the biomass layer after the material is laid. The thickness of the biomass layer is distributed in steps in the width direction of the sintering trolley.

[0010] In the present invention, in the width direction of the sintering trolley, the thickness of the biomass layer is thick in the middle and thin at the edge, wherein the thickness of the biomass layer at the center of the trolley is the largest, and the thickness of the biomass layer near the trolley railing is the smallest.

[0011] In the present invention, the laying thickness of the biomass layer on the sintering material surface is:

[0012] H=H0-ΔH……(1).

[0013] in:

[0014] ΔH=H0×k1×x……(2).

[0015] You will get:

[0016] H=H0-H0×k1×x……(3).

[0017] Where: H represents the thickness of the biomass layer at any position on the sintering trolley, mm. H0 is the thickness of the biomass layer at the center of the trolley in the width direction of the sintering trolley, mm. ΔH is the difference between the thickness of the biomass layer at any of the above positions and the thickness of the biomass layer at the center of the trolley, mm. x represents the distance between any of the above positions and the center of the trolley in the width direction of the sintering trolley, m. k1 is the adjustment coefficient, and the value range of k1 is 0.1-0.5m -1 .

[0018] In the present invention, in the width direction of the sintering trolley, the thickness H0 of the biomass layer at the center of the trolley is:

[0019]

[0020] Where: 烧 is the density of the sintering mixture, kg / m 3 .H 烧 is the thickness of the sintered material layer, mm. C P烧 is the constant pressure specific heat capacity of the sintering mixture, kJ / (kg·℃). T0 is the conventional sintering ignition temperature when no biomass fuel is laid, ℃. ρ 生 is the density of biomass fuel, kg / m 3 . C P生 is the constant pressure specific heat capacity of biomass fuel, kJ / (kg·℃). T1 is the low temperature ignition temperature after laying biomass fuel, ℃. k2 is the adjustment coefficient, and the value range of k2 is 10-30.

[0021] In the present invention, the biomass fuel is a granular solid fuel made from biomass.

[0022] In the present invention, the biomass is one or more of agricultural waste, aquatic plants, oil plants, and organic waste.

[0023] Preferably, the particle size of the biomass fuel is 0.5-5 mm, preferably 1-3 mm.

[0024] In the present invention, the biomass layer is ignited by one or more of electric heat ignition, hot air ignition, and fuel ignition.

[0025] The ignition method described here refers to a method of providing an ignition heat source for igniting the biomass layer. Since the laying of the biomass layer above the sintering material surface can significantly reduce the ignition temperature of the sintering material surface, the ignition method here can preferably be electric heat ignition and / or hot air ignition (oxygen-enriched hot air can be used to further reduce the ignition temperature of the sintering material surface), that is, reducing carbon emissions while reducing ignition energy consumption.

[0026] The fuel ignition mentioned here refers to the combustion of gaseous fuels such as coal gas through an ignition burner to provide a high-temperature flame for ignition of the sintering material surface.

[0027] In the present invention, solid fuel is added to the sintering mixture, and the solid fuel includes any one or both of fossil fuel and biomass fuel.

[0028] Preferably, among all the solid fuels added to the sintering mixture, the biomass fuel accounts for 0-100%, preferably 5-90%, and more preferably 10-80%.

[0029] In view of the high carbon emission in the ignition and sintering process of the existing iron ore sintering process, and the inability to achieve uniform sintering due to the edge effect, which affects the quality of the sintered ore, the present invention proposes a method for igniting iron ore sintering using biomass fuel. The method sprays the biomass fuel on the surface of the sintering mixture so that the sintering surface is covered with a layer of biomass fuel, wherein the thickness of the biomass fuel is arranged in a stepped manner in the width direction of the sintering trolley (preferably in a distribution pattern of thick in the middle and thin at the edge), and ignites the biomass fuel after the material distribution is completed to start sintering. The technical solution of arranging biomass layers in steps on the surface of the sintering material layer for ignition according to the present invention can effectively utilize the characteristics of biomass fuel such as low ignition point, high thermochemical reaction activity, fast combustion speed and high combustion intensity, so that the middle position of the trolley with a thick biomass layer can burn more quickly on the sintering material surface to form a red-hot combustion zone than the edge position of the trolley with a thin biomass layer, thereby making the combustion speed of the middle position of the trolley faster than that of the edge position of the trolley. During the sintering process, the edge effect will cause the vertical sintering speed of the sintering material at the edge of the trolley to be higher than that at the middle position. Finally, the two will offset each other and achieve uniform sintering speed at the edge and middle positions of the trolley. That is, the present invention can effectively alleviate the adverse effects of the edge effect on the sintered ore, comprehensively improve the yield and quality of the sintered ore, and enhance the overall performance of the sintered ore.

[0030] Biomass energy is the fourth largest energy source after coal, oil and natural gas. It is a renewable energy source and a renewable carbon source. The CO2 released by this type of renewable energy material during combustion comes from the CO2 absorbed during its growth. Therefore, biomass fuel has the characteristic of net zero emission of CO2 and is widely regarded as a carbon zero emission energy source. Therefore, the present invention uses biomass fuel for ignition, applies biomass fuel to the ignition link of iron ore sintering, and serves as a low-temperature ignition agent in the sintering ignition process and a trigger for the ignition of fossil fuels such as coke powder or anthracite in the sintering material, thereby achieving clean and green zero-carbon ignition, and significantly reducing carbon emissions compared to the prior art.

[0031] In addition, compared with fossil fuels such as coke powder and anthracite, biomass fuels have the characteristics of low ignition point, high thermochemical reaction activity, fast combustion speed and high combustion intensity. Therefore, electric heat ignition or hot air ignition can be used to ignite biomass fuels. Compared with traditional gas ignition methods, carbon emissions are further reduced, while reducing ignition energy consumption, achieving low-carbon ignition sintering.

[0032] Furthermore, the above-mentioned biomass layer is laid in a stepped arrangement with a thick middle and thin edges. The present invention provides specific biomass layer thickness calculation formulas (1)-(4) based on experiments and engineering applications. The thickness of the biomass layer that needs to be laid at any position of the sintering trolley can be calculated according to the corresponding formula. The thickness of the biomass layer at each position on the sintering trolley is precisely controlled so that the middle position of the trolley with a thicker biomass layer can burn more quickly on the sintering material surface to form a red-hot combustion zone compared to the edge position of the trolley with a thinner biomass layer, thereby making the combustion speed of the middle position of the trolley faster than the combustion speed of the edge position of the trolley, thereby minimizing the edge effect during the sintering process and achieving uniform sintering speed (such as Figure 4 In addition, precise control of the thickness of the biomass layer at each position on the sintering trolley can ensure that the biomass layer only acts in the ignition stage. When the sintering trolley leaves the ignition stage, the biomass layer is burned and does not participate in the sintering process of the subsequent sintering material layer, thereby avoiding its impact on the subsequent sintering process. The corresponding formulas are as follows:

[0033] H=H0-ΔH……(1);

[0034] ΔH=H0×k1×x……(2);

[0035] H=H0-H0×k1×x……(3);

[0036]

[0037] In the above formula, k1 and k2 are both operating condition adjustment coefficients, which can be adjusted according to changes in on-site operating conditions.

[0038] It should be noted that the above formula can be used to dynamically and accurately control the thickness of the biomass layer at any position on the sintering trolley. Therefore, the calculation of the above formula is not only applicable to the case of uniform distribution of the sintering mixture under the biomass layer, but also to the case of convex or concave distribution of the sintering mixture.

[0039] In the present invention, the biomass fuel is a granular solid fuel made of biomass. The particle size of the biomass fuel also needs to be regulated. If the particle size of the biomass fuel is too small, it may cause the biomass fuel to penetrate into the sintering material layer of the lower layer, thereby affecting the subsequent sintering process from multiple aspects such as the air permeability of the material layer and the solid fuel ratio; if the particle size of the biomass fuel is too large, it may be difficult to control the combustion speed and thus the subsequent sintering speed cannot be accurately controlled, thereby weakening the mitigation or elimination of the edge effect. Based on this, the particle size of the biomass fuel in the present invention is generally 0.5-5mm, preferably 1-3mm.

[0040] In the present invention, the biomass includes one or more of agricultural waste, aquatic plants, oil plants, and organic waste. Among them, the biomass of agricultural waste, such as crop straw (such as corn straw), rice husks, sugarcane bagasse, etc. The biomass of aquatic plants, such as microalgae such as Spirulina and Chlorella. The biomass of oil plants, such as rubber trees, blue corals, etc. The biomass of organic waste, such as livestock and poultry manure, urban solid waste, etc. Different biomasses have different corresponding processing technologies, and they are all processed into granular solid fuels in the end. In the present application, the biomass preferably uses biomass of agricultural waste.

[0041] In order to further reduce the carbon emissions during the iron ore sintering process, based on the fact that biomass fuel has the net zero emission characteristics of CO2, the present invention proposes a technical solution of using biomass fuel or part of biomass fuel to replace solid fossil fuels in the sintering mixture. Preferably, considering that adding too much biomass fuel to the sintering mixture may cause the sintering front to move too fast, although it reduces carbon emissions, it may cause the sintering end point to be unstable and the quality of the sintered ore to deteriorate, thus affecting subsequent production. Therefore, the present invention controls the amount of biomass fuel added to the sintering mixture. For example, among all the solid fuels added to the sintering mixture, the proportion of the biomass fuel is 0-100%, preferably 5-90%, and more preferably 10-80%, for example, the proportion of biomass fuel to all solid fuels is 8%, 10% or 12%, etc.

[0042] It should be noted that all formulas in the present invention are obtained by fitting by the inventors based on experiments and engineering applications, and all calculations are obtained by substituting the converted values ​​into the formulas after conversion according to given units (after conversion, only the values ​​are substituted into the formulas without substituting the units, and the units are only used to adjust the size of the values). Alternatively, it can be understood that the coefficients in the formulas, on the one hand, play a role in adaptive adjustment according to the working conditions, and at the same time (by adaptively assigning the corresponding units) play a role in balancing the units on both sides of the equation.

[0043] Compared with the prior art, the present invention has the following beneficial technical effects:

[0044] 1. Low carbon emissions: The present invention uses biomass fuel for ignition, achieving clean and green zero-carbon ignition, and significantly reducing carbon emissions compared to existing technologies.

[0045] Based on the characteristics of biomass fuel such as low ignition point and fast combustion speed, the present invention can adopt ignition methods such as electric heat ignition or hot air ignition to ignite biomass fuel. Compared with the traditional gas ignition method, it further reduces carbon emissions and ignition energy consumption, thereby achieving low-carbon ignition sintering.

[0046] Based on the fact that biomass fuel has the characteristic of net zero emission of CO2, the present invention proposes a technical solution of using biomass fuel or part of biomass fuel to replace solid fossil fuel in sintering mixture, so as to further reduce carbon emissions in the iron ore sintering process.

[0047] 2. Alleviate or eliminate the edge effect, achieve uniform sintering speed in the width direction of the trolley, and improve the overall performance of the sintered ore: The technical solution of arranging the biomass layer on the surface of the sintering material layer for ignition can effectively utilize the characteristics of biomass fuel such as low ignition point, high thermochemical reaction activity, fast combustion speed, and high combustion intensity, so that the middle position of the trolley with a thick biomass layer can burn more quickly on the sintering material surface to form a red-hot combustion zone than the edge position of the trolley with a thin biomass layer, thereby making the combustion speed of the middle position of the trolley faster than that of the edge position of the trolley. During the sintering process, the edge effect will cause the vertical sintering speed of the sintering material at the edge of the trolley to be higher than that at the middle position. Finally, the two will offset each other and achieve uniform sintering speed at the edge and middle positions of the trolley. That is, the present invention can effectively alleviate the adverse effects of the edge effect on the sintered ore, comprehensively improve the yield and quality of the sintered ore, and improve the overall performance of the sintered ore.

[0048] The present invention provides a specific formula for calculating the thickness of the biomass layer based on experiments and engineering applications. According to the corresponding formula, the thickness of the biomass layer that needs to be laid at any position of the sintering trolley can be calculated, thereby accurately controlling the thickness of the biomass layer at each position on the sintering trolley, thereby minimizing the edge effect in the sintering process and achieving increased production and quality of sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a first process flow chart of the method for igniting iron ore using biomass fuel in the present invention;

[0050] Figure 2 A second process flow chart of the method for igniting iron ore using biomass fuels according to the present invention;

[0051] Figure 3 A third process flow chart of the method for igniting iron ore sintering using biomass fuel according to the present invention;

[0052] Figure 4 This is a cross-sectional view of the tail of the sintering machine after the biomass layer is laid in steps and then ignited and sintered in Application Example 1;

[0053] Figure 5 This is a cross-sectional view of the tail of the sintering machine after the biomass layer is evenly laid and then ignited and sintered in Comparative Example 1. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is illustrated below by way of example, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

[0055] According to an embodiment of the present invention, a method for sintering iron ore using biomass fuel ignition is provided.

[0056] A method of igniting iron ore sintering using biomass fuel, spraying biomass fuel on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top, and igniting the biomass layer after the material is laid. The thickness of the biomass layer is distributed in steps in the width direction of the sintering trolley.

[0057] In the present invention, in the width direction of the sintering trolley, the thickness of the biomass layer is thick in the middle and thin at the edge, wherein the thickness of the biomass layer at the center of the trolley is the largest, and the thickness of the biomass layer near the trolley railing is the smallest.

[0058] In the present invention, the laying thickness of the biomass layer on the sintering material surface is:

[0059] H=H0-ΔH……(1).

[0060] in:

[0061] ΔH=H0×k1×x……(2).

[0062] You will get:

[0063] H=H0-H0×k1×x……(3).

[0064] Where: H represents the thickness of the biomass layer at any position on the sintering trolley, mm. H0 is the thickness of the biomass layer at the center of the trolley in the width direction of the sintering trolley, mm. ΔH is the difference between the thickness of the biomass layer at any of the above positions and the thickness of the biomass layer at the center of the trolley, mm. x represents the distance between any of the above positions and the center of the trolley in the width direction of the sintering trolley, m. k1 is the adjustment coefficient, and the value range of k1 is 0.1-0.5m -1 .

[0065] In the present invention, in the width direction of the sintering trolley, the thickness H0 of the biomass layer at the center of the trolley is:

[0066]

[0067] Where: 烧 is the density of the sintering mixture, kg / m 3 .H 烧 is the thickness of the sintered material layer, mm. C P烧 is the constant pressure specific heat capacity of the sintering mixture, kJ / (kg·℃). T0 is the conventional sintering ignition temperature when no biomass fuel is laid, ℃. ρ 生 is the density of biomass fuel, kg / m 3 . C P生 is the constant pressure specific heat capacity of biomass fuel, kJ / (kg·℃). T1 is the low temperature ignition temperature after laying biomass fuel, ℃. k2 is the adjustment coefficient, and the value range of k2 is 10-30.

[0068] In the present invention, the biomass fuel is a granular solid fuel made from biomass.

[0069] In the present invention, the biomass is one or more of agricultural waste, aquatic plants, oil plants, and organic waste.

[0070] Preferably, the particle size of the biomass fuel is 0.5-5 mm, preferably 1-3 mm.

[0071] In the present invention, the biomass layer is ignited by one or more of electric heat ignition, hot air ignition, and fuel ignition.

[0072] In the present invention, solid fuel is added to the sintering mixture, and the solid fuel includes any one or both of fossil fuel and biomass fuel.

[0073] Preferably, among all the solid fuels added to the sintering mixture, the biomass fuel accounts for 0-100%, preferably 5-90%, and more preferably 10-80%.

[0074] Example 1

[0075] like Figure 1 As shown, a method of igniting iron ore sintering using biomass fuel is shown, where the biomass fuel is sprayed on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top, and the biomass layer is ignited after the material is laid. The thickness of the biomass layer is distributed in steps in the width direction of the sintering trolley.

[0076] Example 2

[0077] like Figure 2 As shown, a method of igniting iron ore sintering using biomass fuel is used. The biomass fuel is sprayed on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top. After the material is laid, the biomass layer is ignited. In the width direction of the sintering trolley, the thickness of the biomass layer is thick in the middle and thin at the edge. Among them, the thickness of the biomass layer at the center of the trolley is the largest, and the thickness of the biomass layer near the trolley railing is the smallest.

[0078] Example 3

[0079] like Figure 3 As shown, a method of igniting iron ore sintering using biomass fuel is used, and the biomass fuel is sprayed on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top. After the material is laid, the biomass layer is ignited. In the width direction of the sintering trolley, the thickness of the biomass layer is thick in the middle and thin at the edge. The laying thickness of the biomass layer on the sintering material surface is specifically:

[0080] H=H0-ΔH……(1).

[0081] in:

[0082] ΔH=H0×k1×x……(2).

[0083] You will get:

[0084] H=H0-H0×k1×x……(3).

[0085] Where: H represents the thickness of the biomass layer at any position on the sintering trolley, mm. H0 is the thickness of the biomass layer at the center of the trolley in the width direction of the sintering trolley, mm. ΔH is the difference between the thickness of the biomass layer at any position and the thickness of the biomass layer at the center of the trolley, mm. x represents the distance between any position and the center of the trolley in the width direction of the sintering trolley, m. k1 is the adjustment coefficient, k1 = 0.2m -1 .

[0086] In the width direction of the sintering trolley, the thickness H0 of the biomass layer at the center of the trolley is:

[0087]

[0088] Where: 烧 is the density of the sintering mixture, kg / m 3 .H 烧 is the thickness of the sintered material layer, mm. C P烧 is the constant pressure specific heat capacity of the sintering mixture, kJ / (kg·℃). T0 is the conventional sintering ignition temperature when no biomass fuel is laid, ℃. ρ 生 is the density of biomass fuel, kg / m 3 . C P生 is the constant pressure specific heat capacity of biomass fuel, kJ / (kg·℃). T1 is the low temperature ignition temperature after laying biomass fuel, ℃. k2 is the adjustment coefficient, k2=23.

[0089] Therefore, the laying thickness of the biomass layer on the sintering material surface satisfies the following formula:

[0090]

[0091] Example 4

[0092] Example 3 was repeated, except that the biomass fuel was a granular solid fuel made of biomass, and the biomass was corn stalks, that is, the biomass fuel was corn stalk charcoal, and its particle size was 2 mm.

[0093] Example 5

[0094] Example 4 was repeated, except that the biomass was bagasse. The particle size of the biomass fuel made from bagasse was 3 mm.

[0095] Example 6

[0096] Example 5 was repeated, except that the method for igniting the biomass layer was electric heat ignition, that is, high temperature atmosphere was provided to the biomass layer by electric heat for ignition.

[0097] Example 7

[0098] Example 4 was repeated, except that the method for igniting the biomass layer was hot air ignition, that is, hot air was used to provide a high-temperature atmosphere for the biomass layer for ignition.

[0099] Example 8

[0100] Example 4 was repeated, except that the biomass layer was ignited by fuel ignition. The fuel used was coal gas as a gaseous fuel. That is, the coal gas was burned through an ignition burner and sprayed out a high-temperature flame to ignite the biomass layer.

[0101] Example 9

[0102] Example 7 was repeated, except that solid fuel was added to the sintering mixture. The solid fuel included coke powder and corn straw charcoal. Among all the solid fuels added to the sintering mixture, the corn straw charcoal accounted for 12%.

[0103] Example 10

[0104] Example 9 was repeated, except that the corn straw charcoal accounted for 8% of all the solid fuels added to the sintering mixture.

[0105] Application Example 1

[0106] The method described in Example 7 was used for 280m 2 Sintering machine, where the width of the sintering trolley is 3.5m and the length of the sintering trolley is 1.5m. First, the sintering mixture is evenly laid on the sintering trolley, and then the biomass fuel of corn straw charcoal is sprayed on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top. After the laying is completed, the biomass layer is ignited by hot air to complete the sintering.

[0107] In the width direction of the sintering trolley, the thickness of the biomass layer is thick in the middle and thin at the edge. The laying thickness of the biomass layer on the sintering material surface satisfies the following formula:

[0108]

[0109] Where: H represents the thickness of the biomass layer at any position on the sintering trolley, mm. 烧 is the density of the sintering mixture, ρ 烧 =2000kg / m 3 .H 烧 is the thickness of the sintering layer, H 烧 =900mm. P烧 is the constant pressure specific heat capacity of the sintering mixture, C P烧 =1.3kJ / (kg·℃). T0 is the normal sintering ignition temperature when no biomass fuel is laid, T0 = 1150℃. ρ 生is the density of biomass fuel, ρ 生 =750kg / m 3 . C P生 is the constant pressure specific heat capacity of biomass fuel, C P生 =1.1kJ / (kg·℃). T1 is the low temperature ignition temperature after laying biomass fuel, T1=700℃. x represents the distance between any of the above positions and the center of the sintering trolley in the width direction, m. k1 and k2 are both adjustment coefficients, k1=0.2m -1 , k2=23.

[0110] According to the above formula, the laying thickness of the biomass layer at any position on the sintering trolley can be calculated. Taking the center position of the trolley x1=0m, the edge position of the trolley x3=1.75m, and the middle position between the center of the trolley and the edge of the trolley x2=0.875m, the thickness of the biomass layer at the corresponding positions is calculated and recorded in the following Table 1. After the sintering is completed, the performance of the obtained sintered ore is tested, and the corresponding test data is recorded in the following Table 2.

[0111] Comparative Example 1

[0112] It is also used in a 280m 2 The sintering machine has a sintering trolley with a width of 3.5 m and a length of 1.5 m. First, the sintering mixture is evenly laid on the sintering trolley, and then the biomass fuel of corn straw charcoal is evenly sprayed on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top. After the laying is completed, the biomass layer is ignited by hot air and sintering is completed. The materials and other process conditions used in Comparative Example 1 are the same as those in Application Example 1.

[0113] Since the biomass fuel is evenly laid on the sintering mixture, the thickness of the biomass layer at any position on the sintering trolley is consistent in Comparative Example 1. After the sintering is completed, the performance of the obtained sintered ore is tested, and the corresponding test data are recorded in Table 2 below.

[0114] Table 1 Thickness of biomass layer at different positions in the width direction of the sintering trolley

[0115]

[0116] Table 2 Sintered ore output and quality indicators

[0117]

[0118] It can be seen from Tables 1 and 2 above that the technical solution of arranging biomass layers in steps on the surface of the sintering material layer for ignition by the present application can effectively utilize the characteristics of biomass fuel such as low ignition point, high thermochemical reaction activity, fast combustion speed and high combustion intensity, so that the middle position of the trolley with a thicker biomass layer can burn more quickly on the sintering material surface to form a red-hot combustion zone than the edge position of the trolley with a thinner biomass layer, thereby making the combustion speed of the middle position of the trolley faster than that of the edge position of the trolley. During the sintering process, the edge effect will cause the vertical sintering speed of the sintering material at the edge of the trolley to be higher than that in the middle position. Finally, the two will offset each other and achieve uniform sintering speed at the edge and middle positions of the trolley, such as Figure 4 shown.

[0119] Compared with the method of evenly laying the biomass layer in Comparative Example 1, the sintered ore obtained by Application Example 1 of the technical solution of the present application has significantly better performance indicators such as sintered ore finished product rate and sintered ore drum strength than Comparative Example 1, that is, the present application effectively alleviates the adverse effects of the edge effect on the sintered ore, comprehensively improves the output and quality of the sintered ore, and improves the overall performance of the sintered ore.

Claims

1. A method for sintering iron ore using biomass fuel ignition, characterized in that: The biomass fuel is sprayed on the surface of the sintering mixture to form a sintering material layer and a biomass layer from bottom to top. After the material is laid, the biomass layer is ignited; wherein the thickness of the biomass layer is distributed in steps in the width direction of the sintering trolley.

2. The method according to claim 1, characterized in that: In the width direction of the sintering trolley, the thickness of the biomass layer is thick in the middle and thin at the edge; among them, the thickness of the biomass layer at the center of the trolley is the largest, and the thickness of the biomass layer near the trolley railing is the smallest.

3. The method according to claim 1 or 2, characterized in that: The laying thickness of the biomass layer on the sintering material surface is: H=H0-ΔH……(1); in: ΔH=H0×k1×x……(2); You will get: H=H0-H0×k1×x……(3); Where: H represents the thickness of the biomass layer at any position on the sintering trolley, mm; H0 is the thickness of the biomass layer at the center of the trolley in the width direction of the sintering trolley, mm; ΔH is the difference between the thickness of the biomass layer at any of the aforementioned positions and the thickness of the biomass layer at the center of the trolley, mm; x represents the distance between any of the aforementioned positions and the center of the trolley in the width direction of the sintering trolley, m; k1 is the adjustment coefficient, and the value range of k1 is 0.1-0.5m -1 .

4. The method according to claim 3, characterized in that: In the width direction of the sintering trolley, the thickness H0 of the biomass layer at the center of the trolley is: Where: 烧 is the density of the sintering mixture, kg / m 3 ;H 烧 is the thickness of the sintering material layer, mm; C P烧 is the constant pressure specific heat capacity of the sintering mixture, kJ / (kg·℃); T0 is the conventional sintering ignition temperature when no biomass fuel is laid, ℃; ρ 生 is the density of biomass fuel, kg / m 3 ; C P生 is the constant pressure specific heat capacity of biomass fuel, kJ / (kg·℃); T1 is the low-temperature ignition temperature after laying biomass fuel, ℃; k2 is the adjustment coefficient, and the value range of k2 is 10-30.

5. The method according to any one of claims 1 to 4, characterized in that: The biomass fuel is a granular solid fuel made from biomass.

6. The method according to claim 5, characterized in that: The biomass is one or more of agricultural waste, aquatic plants, oil plants, and organic waste.

7. The method according to claim 6, characterized in that: The particle size of the biomass fuel is 0.5-5 mm, preferably 1-3 mm.

8. The method according to any one of claims 1 to 7, characterized in that: The biomass layer is ignited by one or more of electric heat ignition, hot air ignition and fuel ignition.

9. The method according to any one of claims 1 to 8, characterized in that: Solid fuel is added to the sintering mixture; the solid fuel includes any one or two of fossil fuel and biomass fuel.

10. The method according to claim 9, characterized in that: Among all the solid fuels added to the sintering mixture, the biomass fuel accounts for 0-100%, preferably 5-90%, and more preferably 10-80%.

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