A fuel supply method with high fuel utilization rate

Abstract

A fuel supply method with high fuel utilization rate screens out fine coke powder and fine coal powder in the sintering process and sends them into the blast furnace. According to the relationship diagram between the content of small particle fuels in sintering fuels and the fuel quantity required per unit of sintered ore, precise control of the fuel addition amounts in the blast furnace and sintering is achieved. On the premise that the total heat in the sintering process and the blast furnace process remains unchanged, the combustion efficiency of the fuel is improved, the small particle fuels carried in the sintering flue gas are reduced, and the quality of the sintered ore is ensured. At the same time, the sintering fuel preparation workshop is cancelled, and the existing blast furnace fuel preparation workshop is used for processes such as crushing and screening of sintering fuels. The small particle fuels screened out do not need to be transported, reducing dust emission and also saving infrastructure investment, having good economic benefits and strong practicability.

Description

Technical Field

[0001] The present invention relates to a fuel supply method, and particularly to a fuel supply method with high fuel utilization rate, belonging to the field of iron and steel smelting. Background Art

[0002] Both sintering and blast furnace are important parts in the metallurgical process. The existing fuel supply processes for sintering and blast furnace are as Figure 3 , and the blast furnace fuels include coke, anthracite and bituminous coal. Among them, in the blast furnace, coke not only provides heat, but also mainly plays a role of skeleton support and reducing agent. The blast furnace usually requires the particle size of coke to be >8 mm, and the fuel <8 mm after screening is sent to the sintering process for heat supply.

[0003] Due to the high price of coke, in the fuel supply process of the blast furnace, generally the reasonable minimum coke dosage is determined first, and the insufficient heat part is then injected from the tuyere of the blast furnace by pulverized anthracite. In order to further reduce the cost of hot metal, a small amount of pulverized bituminous coal with low price is also injected, but the adaptability of the blast furnace to bituminous coal is limited. In order to ensure the normal operation of the blast furnace, bituminous coal cannot be used entirely. That is, the heat in the blast furnace is provided by coke, anthracite and bituminous coal together.

[0004] In sintering, a large number of studies have shown that the suitable fuel particle size for the sintering process should be 0.5 - 3 mm. The fuel with <0.5 mm has low thermal efficiency and is easily sucked away under high negative pressure in sintering. The higher the content of <0.5 mm in the fuel, the greater the fuel consumption for producing unit mass of sinter. It basically conforms to the rule as Figure 2 .

[0005] In the existing process, the anthracite externally supplied by the sintering process is first crushed by a pair of rolls to less than 15 mm, and then together with the <8 mm coke fines produced by the blast furnace, it is crushed by four rolls to less than 3 mm and sent to the sintering batching. Due to the high moisture content of anthracite, it is very difficult to separate the fine-grained coal powder with a particle size of less than 0.5 mm by mechanical screening. At the same time, the current national standard and on-site operation only stipulate the upper limit value, that is, the content of fuel with <3 mm should be greater than 80% during the sintering fuel crushing, and there is no clear regulation on the lower limit value, that is, the content of fine-grained fuel with a particle size of less than 0.5 mm in the sintering fuel is relatively high. On the one hand, it is inevitable to form fine-grained coal powder with <0.5 mm during the sintering fuel crushing. On the other hand, the on-site personnel are evaluated according to the upper limit value, and often adjust the roll gap of the four-roll crushing to be smaller, resulting in over-crushing of the fuel. The above factors together lead to the problem of high content of fine-grained coal powder in the sintering fuel and low combustion efficiency.

[0006] In the current blast furnace and sintering fuel supply processes, for most enterprises, the proportion of particles <0.5mm in sintering fuel exceeds 35%. Due to high moisture content, these fuels have poor separation effect during screening. During the sintering process, the moisture in the fuel gradually evaporates, and small particle fuels are easily sucked away under the high negative pressure of sintering. As a result, the sintering temperature cannot reach the set value, which affects the quality of sintered ore, causes fuel waste, and leads to a relatively low overall combustion efficiency of the fuel. Summary of the Invention

[0007] Aiming at the problem in the prior art that the content of fine-grained pulverized coal with particle size <0.5mm in sintering fuel is relatively high, resulting in poor quality of sintered ore and relatively low overall combustion efficiency of the fuel, the present invention proposes a fuel supply method with high fuel utilization rate. The present invention separates the fine-grained pulverized coal with particle size <0.5mm from the sintering fuel, sends it to the blast furnace for utilization, fits the relationship between the fine-grained pulverized coal with particle size <0.5mm in the fuel and the fuel required for unit sintered ore, calculates the total heat required in the blast furnace and sintering respectively, and then adjusts the quality of coke, anthracite, and bituminous coal added in the blast furnace and sintering accordingly, precisely controlling the fuel supply in the blast furnace and sintering processes and improving the combustion efficiency of the fuel.

[0008] According to the embodiment of the present invention, a fuel supply method with high fuel utilization rate is provided.

[0009] A fuel supply method with high fuel utilization rate, the method includes the following steps:

[0010] 1) Fuel supply routes in the blast furnace process and sintering process: Provide coke, bituminous coal, and anthracite as fuels to the blast furnace process. Among them, large particle coke powder in the coke is sent to the blast furnace process, and small particle coke powder is sent to the sintering process. At the same time, provide anthracite as fuel supplement to the sintering process, and return the fine coke powder in the small particle coke powder and the fine pulverized coal in the anthracite in the sintering process to the blast furnace process;

[0011] 2) According to the heat required for the target output of hot metal in the blast furnace process and the blast furnace conditions, determine the minimum input amount of large particle coke powder and the maximum input amount of bituminous coal; further determine the addition amount of anthracite in the blast furnace process according to the minimum input amount of large particle coke powder and the maximum input amount of bituminous coal, and determine the total addition amount of coke according to the proportion of large particle coke powder in the coke and the minimum input amount of large particle coke powder in the blast furnace;

[0012] 3) According to the proportion of small particle coke powder in the coke and the proportion of fine coke powder in the small particle coke powder, determine the actual input amount of small particle coke powder added to the sintering process; according to the heat required for the target output of sintered ore in the sintering process and the actual input amount of small particle coke powder added to the sintering process, determine the addition amount of anthracite in the sintering process; further determine the actual input amount of anthracite in the sintering process according to the proportion of fine pulverized coal in the anthracite required in the sintering process;

[0013] 4) Mix the fine coke powder in step 2) and the fine pulverized coal in step 3), and then spray them into the blast furnace; adjust the addition amount of fuel in the blast furnace process and the sintering process according to the respective contents and calorific values of the fine coke powder and the fine pulverized coal, and then cycle through steps 1)-4).

[0014] Preferably, the method further includes: 5) After the adjustment in step 4) is completed, compare the addition amounts of large particle coke powder, bituminous coal, and anthracite in the blast furnace process under the adjusted new process conditions, and the addition amounts of small particle coke powder and anthracite in the sintering process with those before adjustment, i.e., the addition amounts of large particle coke powder, bituminous coal, and anthracite in the blast furnace process, and the addition amounts of small particle coke powder and anthracite in the sintering process before adjustment. When the change amount a ≤ 1%, preferably a ≤ 0.5%, stop the cycle.

[0015] Preferably, the large particle coke powder in step 1) is coke particles with a particle size ≥ 8 mm, and the small particle coke powder in step 1) is coke particles with a particle size < 8 mm.

[0016] Preferably, the fine coke powder in step 1) is coke particles with a particle size < 0.5 mm.

[0017] Preferably, the fine pulverized coal in step 1) is pulverized coal particles with a particle size < 0.5 mm.

[0018] Preferably, the minimum incorporation amount of the large particle coke powder in step 2) is the mass of the coke as the skeleton in the blast furnace process.

[0019] Preferably, the maximum incorporation amount of the bituminous coal in step 2) is the maximum mass of the bituminous coal that does not affect the operation according to the blast furnace conditions.

[0020] The total addition amount of anthracite and coke in the blast furnace process in step 2) is as follows:

[0021] Q f = γ * A * Q1 + B * Q2 + C * Q3... (Equation 1)

[0022] In the formula, Q f is the total heat required in the blast furnace process; A is the total addition amount of coke; Q1 is the calorific value of coke; γ is the proportion of coke entering the blast furnace burden; B is the mass of anthracite added to the blast furnace; Q2 is the calorific value of anthracite; C is the mass of bituminous coal added to the blast furnace; Q3 is the calorific value of bituminous coal.

[0023] Preferably, the actual addition amounts of small particle coke powder and anthracite in the sintering process in step 3) are as follows:

[0024] Detect that the total mass of small particle coke powder and fine pulverized coal is Z, and the total heat is Q4, then there is:

[0025] X + Y = Z... (Equation 2)

[0026] X * Q1 + Y * Q2 = Z * Q4... (Equation 3)

[0027] Based on Equation 2 and Equation 3, the values of X and Y can be obtained; then in the sintering process:

[0028] Q s = [(1 - γ) * A - X] * Q1 + (P - Y) * Q2... (Equation 4)

[0029] In the formula, X is the content of fine coke powder in small particle coke powder; Y is the content of fine coal powder in anthracite; (1 - γ) * A - X is the actual addition amount of small particle coke powder in the sintering process, and P - Y is the actual addition amount of anthracite in the sintering process.

[0030] Preferably, in step 4), adjusting the addition amount of fuel in the blast furnace process and the sintering process according to the respective contents and calorific values of fine coke powder and fine coal powder is as follows:

[0031] Since the demand for coke in the blast furnace remains unchanged, the heat required for smelting 1 ton of hot metal also remains unchanged, and the adaptability of the blast furnace to bituminous coal is limited. When the quality of bituminous coal takes the maximum value, then there is:

[0032] A' = A... (Equation 5)

[0033] C' = C... (Equation 6)

[0034] γ * A' * Q1 + Z * Q4 + (B' * Q2 + C' * Q3) = γ * A * Q1 + B * Q2 + C * Q3... (Equation 7)

[0035] In the formula, A' is the total mass of coke added in the blast furnace under the new process conditions; B' is the mass of anthracite added in the blast furnace under the new process conditions; C' is the mass of bituminous coal added in the blast furnace under the new process conditions;

[0036] At the same time, the heat calculation in the sintering process is as follows:

[0037] [(1 - γ) * A' - X] * Q1 + (P' - Y) * Q2 = [(1 - γ) * A * Q1 + P * Q2]λ... (Equation 8)

[0038]

[0039] In the formula, P' is the mass of anthracite added in the sintering under the new process conditions; M' is the mass of fuel required per ton of sinter in the new process; M is the mass of fuel required per ton of sinter in the original process;

[0040] Among them, the calculation methods of M and M' are as follows:

[0041] M = 30n2 +4.2n + 50.02……(Equation 10)

[0042] In the formula, n is the proportion of small - particle mixed fuel in the sintering fuel, %.

[0043] According to the above formula, the values of A', B', C', and P' can be calculated, that is, the masses of coke, anthracite, and bituminous coal added to the blast furnace under the new process conditions, and the mass of anthracite replenished to the sintering process.

[0044] Preferably, when the mass of bituminous coal added to the blast furnace does not take the maximum value, correspondingly:

[0045] B”*Q2 + C”*Q3 = B'*Q2 + C'*Q3……(Equation 11)

[0046] In the formula, C” is the mass of bituminous coal added to the blast furnace, and its value range is 0 - C'; B” is the mass of anthracite added to the blast furnace.

[0047] Preferably, step 1) is specifically: Feed coke into the blast - furnace raw material preparation process, screen to obtain large - particle coke powder with a particle size of ≥8 mm and small - particle coke powder with a particle size of <8 mm. Send the large - particle coke powder to the blast - furnace burdening, and send the small - particle coke powder to the sintering burdening. Mix and crush the anthracite replenished to the blast furnace and sintering process to obtain anthracite with a particle size of 0 - 15 mm, separate the anthracite replenished to the sintering process and mix it with the small - particle coke powder for secondary crushing to 0 - 3 mm, and then dry to obtain a mixed fuel; Screen the 0 - 3 mm mixed fuel to obtain large - particle mixed fuel with a particle size of 0.5 - 3 mm and send it to sintering. The small - particle mixed fuel composed of fine coke powder with a particle size of <0.5 mm and fine coal powder with a particle size of <0.5 mm is mixed with the anthracite and bituminous coal replenished to the blast furnace and then ground. After grinding to a proportion of <200 mesh accounting for 80%, it is passed through bag - type dust removal to obtain pulverized coal for blast - furnace injection.

[0048] Preferably, step 1) further includes hot - air drying: Perform hot - air drying on the 0 - 3 mm mixed fuel before screening.

[0049] Preferably, hot - air drying is carried out while grinding the anthracite and bituminous coal replenished to the blast furnace after mixing.

[0050] Preferably, providing coke, bituminous coal, and anthracite to the blast - furnace process, providing anthracite to the sintering process, and returning the fine coke powder in the small - particle coke powder and the fine coal powder in the anthracite in the sintering process to the blast - furnace process in step 1) are all carried out in the blast - furnace raw material preparation process.

[0051] In the prior art, since the functions of coke in the blast furnace are not only to provide heat, but also mainly to play a role in skeleton support and reducing agent. Due to the relatively high price of coke, in the actual application process, generally, the reasonable minimum coke dosage in the blast furnace is first determined, and then according to the total heat required in the blast furnace, the pulverized anthracite is injected from the tuyere of the blast furnace for the part with insufficient heat to reach the target temperature of the blast furnace. At the same time, some bituminous coal is injected to further reduce the cost. In addition, the coke added to the blast furnace includes large particle coke powder and small particle coke powder. Usually, the large particle coke powder is sent into the blast furnace, and the small particle coke powder is sent into the sintering process. In the sintering process, the small particle coke powder screened from the blast furnace fuel is preferentially used as the sintering fuel, and the insufficient part is provided by anthracite. That is, the heat in the sintering process is provided by two parts: small particle coke powder and anthracite, and the heat in the blast furnace process is jointly provided by three parts: small particle coke powder, anthracite and bituminous coal.

[0052] In the present invention, since the fuel thermal efficiency of fine coke powder and fine coal powder is low during the sintering process and is easily sucked away under the high negative pressure in the sintering process, the small particle coke and anthracite to be sent to sintering are broken and screened to obtain large particle mixed fuel with a particle size ≥ 0.5 mm and small particle mixed fuel with a particle size < 0.5 mm (mixed fuel composed of fine coke powder and fine coal powder with a particle size < 0.5 mm). The obtained large particle mixed fuel is sent into the sintering process, and the small particle mixed fuel is sent into the blast furnace for complete combustion. This improves the fuel utilization rate and also reduces the small particle fuel carried in the sintering flue gas, facilitating the dust removal of the sintering flue gas.

[0053] In the present invention, since the total heat required for the blast furnace and the sintering process remains unchanged, and at the same time, coke plays a role in skeleton support and reduction in the blast furnace, the heat supply part can be supplemented with anthracite and bituminous coal. Therefore, the demand for coke in the blast furnace remains unchanged. In addition, since the adaptability of the blast furnace to bituminous coal is limited, that is, there is a maximum value for the addition amount of bituminous coal in the blast furnace. Therefore, it can be concluded that when the addition amount of bituminous coal in the blast furnace is the maximum value, the heat of the anthracite reduced in the blast furnace fuel is equal to the heat of the small particle mixed fuel (i.e., the mixed fuel composed of fine coke powder with a particle size < 0.5 mm and fine coal powder with a particle size < 0.5 mm). Since the addition amount of coke in the blast furnace fuel remains unchanged, the heat provided by the increased anthracite in sintering is equal to the heat provided by the small particle mixed fuel. That is, the addition amounts of each fuel in the blast furnace process and the sintering process that meet the combustion requirements can be determined first, and then the total mass and total heat of the small particle mixed fuel under the current process conditions can be calculated. The masses of coke and anthracite in the small particle mixed fuel can be calculated respectively, so as to calculate the masses of coke, anthracite and bituminous coal required in the blast furnace and the masses of coke and anthracite required in sintering under the new process conditions. Then, according to the new process conditions, the addition amounts of each fuel in the sintering process and the blast furnace process are further adjusted for circulation. Preferably, when the addition amount of bituminous coal in the blast furnace does not take the maximum value, it is only necessary that the total heat provided by the bituminous coal and anthracite added to the blast furnace remains unchanged (meeting Equation 11).

[0054] In the present invention, the more small particle fuels with a size less than 0.5 mm in the sintering fuel, the lower the combustion efficiency of the fuel. To improve the accuracy of fuel calculation, the present invention summarizes the relationship diagram between the content of small particle fuels in the sintering fuel and the fuel quantity required per unit sintered ore, as shown in Figure 2 , according to the relationship between M and n (the percentage of small particle fuels with a size less than 0.5 mm in the sintering fuel), the overall combustion efficiency of the fuel under the current proportion of small particle fuels can be obtained. Thus, after feeding the small particle fuels in the sintering fuel into the blast furnace, the masses of anthracite and bituminous coal added in the blast furnace process and the sintering process can be accurately calculated, avoiding excessive or insufficient fuel, which may cause fuel waste or result in the combustion temperature in the blast furnace process and the sintering process not reaching the predetermined value.

[0055] In the present invention, since the current sintering fuel supply process is carried out in the sintering fuel preparation workshop, the crushing and screening of small particle coke and anthracite sent to the sintering process are both carried out in the sintering fuel preparation workshop, resulting in a long transfer route for the screened small particle mixed fuel to return to the blast furnace process, high transfer costs, and easy generation of dust during transfer. The fugitive emissions caused by the dust are serious. Therefore, the present invention combines the treatment of small particle coke and anthracite sent to the sintering process into the blast furnace fuel preparation process, cancels the original sintering fuel preparation workshop, and the fine coke powder and fine coal powder with a size less than 0.5 mm after screening can be used locally for blast furnace coal injection, reducing logistics transfer and dust, and saving infrastructure investment at the same time.

[0056] In the present invention, since the externally supplied anthracite and bituminous coal usually have a high moisture content, which may affect the screening or air separation effect of the small particle mixed fuel, hot air drying and / or air separation are introduced after the sintering fuel is crushed, and hot air drying is introduced during the coal grinding process of the blast furnace fuel. The heat source is the low-oxygen hot waste gas produced by the hot blast stove in the blast furnace process, and the oxygen concentration is <11%.

[0057] In the present invention, according to the total heat required in the sintering and the blast furnace respectively, and the masses of fine coke powder and fine coal powder in the small particle mixed fuel, after adjusting the addition amounts of coke, anthracite and bituminous coal in the blast furnace, and the addition amounts of coke and anthracite in the sintering process, new process conditions are formed. Under the new process conditions, the masses of coke and anthracite in the small particle mixed fuel will change again, and it is necessary to readjust the masses of coke, anthracite and bituminous coal added in the blast furnace, and the mass of anthracite supplemented to the sintering process to ensure that the total heat in the blast furnace and the sintering process remains unchanged and ensure stable fuel supply. When the change rate a of the fuel quality ≤1%, it is considered that the fuel supply in the blast furnace process and the sintering process is stable, and the cyclic steps 1)-4) are stopped. Among them, the change rate a of the fuel quality is the average value of the change rates of the masses of each fuel.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] 1. A fuel supply method with high fuel utilization rate provided by the present invention screens out fine coke powder and fine coal powder in the sintering process and sends them into the blast furnace. According to the relationship diagram between the content of small-particle fuel in sintering fuel and the fuel amount required per unit of sintered ore, precise control of the fuel addition amount in the blast furnace and sintering is achieved. On the premise that the total heat in the sintering process and the blast furnace process remains unchanged, the combustion efficiency of the fuel is improved, the small-particle fuel carried in the sintering flue gas is reduced, and the quality of the sintered ore is ensured.

[0060] 2. A fuel supply method with high fuel utilization rate provided by the present invention cancels the sintering fuel preparation workshop and uses the existing blast furnace fuel preparation workshop to carry out processes such as crushing and screening of sintering fuel. The screened small-particle fuel does not need to be transported, reducing dust and also saving infrastructure investment, with good economic benefits and strong practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is the fuel supply route of Embodiment 1 in a fuel supply method with high fuel utilization rate provided by the present invention.

[0062] Figure 2 It is the relationship diagram between the content of small-particle fuel and the fuel amount required per unit of sintered ore in a fuel supply method with high fuel utilization rate provided by the present invention.

[0063] Figure 3 It is the fuel supply process diagram of the existing sintering and blast furnace. DETAILED DESCRIPTION OF THE INVENTION

[0064] The technical solutions of the present invention will be illustrated by examples below. The scope of protection claimed by the present invention includes but is not limited to the following examples.

[0065] According to the implementation scheme of the present invention, a fuel supply method with high fuel utilization rate is provided.

[0066] A fuel supply method with high fuel utilization rate, the method includes the following steps:

[0067] 1) Fuel supply routes in the blast furnace process and the sintering process: Provide coke, bituminous coal, and anthracite as fuels to the blast furnace process. Among them, the large-particle coke powder in the coke is sent into the blast furnace process, and the small-particle coke powder is sent into the sintering process. At the same time, anthracite is provided as a fuel supplement to the sintering process, and the fine coke powder in the small-particle coke powder and the fine coal powder in the anthracite in the sintering process are returned to the blast furnace process;

[0068] 2) Determine the minimum dosage of large - particle coke powder and the maximum dosage of bituminous coal according to the heat required for the target molten iron output of the blast - furnace process and the blast - furnace conditions; further determine the addition amount of anthracite in the blast - furnace process based on the minimum dosage of large - particle coke powder and the maximum dosage of bituminous coal, and determine the total addition amount of coke according to the proportion of large - particle coke powder in the coke and the minimum dosage of large - particle coke powder in the blast - furnace;

[0069] 3) Determine the actual addition amount of small - particle coke powder added to the sintering process according to the proportion of small - particle coke powder in the coke and the proportion of fine coke powder in the small - particle coke powder; determine the addition amount of anthracite in the sintering process according to the heat required for the target output of sinter in the sintering process and the actual addition amount of small - particle coke powder added to the sintering process; further determine the actual addition amount of anthracite in the sintering process according to the proportion of fine coal powder in the anthracite required in the sintering process;

[0070] 4) Mix the fine coke powder in step 2) and the fine coal powder in step 3) and spray them into the blast - furnace; and adjust the addition amount of fuel in the blast - furnace process and the sintering process according to the respective contents and calorific values of the fine coke powder and the fine coal powder, and then cycle through steps 1) - 4).

[0071] Preferably, the method further includes: 5) After the adjustment in step 4), compare the addition amounts of large - particle coke powder, bituminous coal, and anthracite in the blast - furnace process under the adjusted new process conditions, the addition amounts of small - particle coke powder and anthracite in the sintering process, with the addition amounts of large - particle coke powder, bituminous coal, and anthracite in the blast - furnace process before adjustment, and the addition amounts of small - particle coke powder and anthracite in the sintering process before adjustment. When the change amount a ≤ 1%, preferably a ≤ 0.5%, stop the cycle.

[0072] Preferably, the large - particle coke powder in step 1) is coke particles with a particle size ≥ 8 mm, and the small - particle coke powder in step 1) is coke particles with a particle size < 8 mm.

[0073] Preferably, the fine coke powder in step 1) is coke particles with a particle size < 0.5 mm.

[0074] Preferably, the fine coal powder in step 1) is coal powder particles with a particle size < 0.5 mm.

[0075] Preferably, the minimum dosage of the large - particle coke powder in step 2) is the mass of the coke as the skeleton in the blast - furnace process.

[0076] Preferably, the maximum dosage of the bituminous coal in step 2) is the maximum mass of bituminous coal that does not affect the operation according to the blast - furnace conditions.

[0077] The addition amount of anthracite and the total demand of coke in the blast - furnace process in step 2) are:

[0078] Qf = γ * A * Q1 + B * Q2 + C * Q3……(Equation 1)

[0079] Wherein, Q f is the total heat required in the blast furnace process; A is the total addition amount of coke; Q1 is the calorific value of coke; γ is the proportion of coke entering the blast furnace burden; B is the mass of anthracite added to the current blast furnace; Q2 is the calorific value of anthracite; C is the mass of bituminous coal added to the current blast furnace; Q3 is the calorific value of bituminous coal.

[0080] Preferably, the actual addition amounts of small particle coke powder and anthracite in the sintering process described in step 3) are as follows:

[0081] Detect that the total mass of small particle coke powder and fine coal powder is Z, and the total heat is Q4, then there is:

[0082] X + Y = Z……(Equation 2)

[0083] X * Q1 + Y * Q2 = Z * Q4……(Equation 3)

[0084] According to Equation 2 and Equation 3, the values of X and Y can be obtained; then in the sintering process:

[0085] Q s = [(1 - γ) * A - X] * Q1 + (P - Y) * Q2……(Equation 4)

[0086] Wherein, X is the content of fine coke powder in small particle coke powder; Y is the content of fine coal powder in anthracite; (1 - γ) * A - X is the actual addition amount of small particle coke powder in the sintering process, and P - Y is the actual addition amount of anthracite in the sintering process.

[0087] Preferably, the adjustment of the fuel addition amounts in the blast furnace process and the sintering process according to the respective contents and calorific values of fine coke powder and fine coal powder described in step 4) is as follows:

[0088] Since the demand for coke in the blast furnace remains unchanged, the heat required to smelt 1 ton of hot metal also remains unchanged, and the adaptability of the blast furnace to bituminous coal is limited. When the mass of bituminous coal takes the maximum value, then there is:

[0089] A' = A……(Equation 5)

[0090] C' = C……(Equation 6)

[0091] γ * A' * Q1 + Z * Q4 + (B' * Q2 + C' * Q3) = γ * A * Q1 + B * Q2 + C * Q3……(Equation 7)

[0092] Wherein, A' is the total mass of coke added to the blast furnace under the new process conditions; B' is the mass of anthracite added to the blast furnace under the new process conditions; C' is the mass of bituminous coal added to the blast furnace under the new process conditions;

[0093] Meanwhile, the heat calculation in the sintering process is as follows:

[0094] [(1 - γ)*A' - X]*Q1 + (P' - Y)*Q2 = [(1 - γ)*A*Q1 + P*Q2]λ... (Equation 8)

[0095]

[0096] In the formula, P' is the mass of anthracite added in sintering under the new process conditions; M' is the fuel mass required per ton of sinter in the new process; M is the fuel mass required per ton of sinter in the original process;

[0097] Among them, the calculation methods of M and M' are as follows:

[0098] M = 30n 2 + 4.2n + 50.02... (Equation 10)

[0099] In the formula, n is the proportion of small particle mixed fuel in the sintering fuel, %.

[0100] According to the above formula, the values of A', B', C', and P' can be calculated, that is, the masses of coke, anthracite, and bituminous coal added to the blast furnace under the new process conditions, and the mass of anthracite supplemented to the sintering process.

[0101] Preferably, when the mass of bituminous coal added to the blast furnace does not take the maximum value, correspondingly:

[0102] B”*Q2 + C”*Q3 = B'*Q2 + C'*Q3... (Equation 11)

[0103] In the formula, C” is the mass of bituminous coal added to the blast furnace, and its value range is 0 to C'; B” is the mass of anthracite added to the blast furnace.

[0104] Preferably, step 1) is specifically: feeding coke into the blast furnace raw material preparation process, screening to obtain large particle coke powder with a size of ≥ 8 mm and small particle coke powder with a size of < 8 mm, sending the large particle coke powder to the blast furnace burdening, and sending the small particle coke powder to the sintering burdening. The anthracite supplemented to the blast furnace and the sintering process is mixed and crushed to obtain anthracite with a size of 0 to 15 mm, separating the anthracite supplemented to the sintering process and mixing it with the small particle coke powder for secondary crushing to 0 to 3 mm, drying to obtain a mixed fuel; screening the 0 to 3 mm mixed fuel to obtain large particle mixed fuel with a size of 0.5 to 3 mm and sending it to sintering, and the small particle mixed fuel composed of fine coke powder with a size of < 0.5 mm and fine coal powder with a size of < 0.5 mm is mixed with the anthracite and bituminous coal supplemented to the blast furnace and ground. After grinding to a proportion of < 200 mesh accounting for 80%, it passes through bag dust removal to obtain pulverized coal for blast furnace injection.

[0105] Preferably, step 1) further includes hot air drying: hot air drying is carried out on the mixed fuel of 0-3 mm before screening.

[0106] Preferably, hot air is introduced for drying while anthracite and bituminous coal supplemented into the blast furnace are ground after being mixed.

[0107] Preferably, providing coke, bituminous coal and anthracite to the blast furnace process, providing anthracite to the sintering process, and returning the fine coke powder in the small particle coke powder and the fine coal powder in the anthracite in the sintering process to the blast furnace process in step 1) are all carried out in the blast furnace raw material preparation process.

[0108] Example 1

[0109] Fuel supply routes in the blast furnace process and the sintering process: As Figure 1 shown, coke is fed into the blast furnace raw material preparation process, and large particle coke powder with a size of ≥8 mm and small particle coke powder with a size <8 mm are obtained by screening. The large particle coke powder is sent to blast furnace batching, and the small particle coke powder is sent to sintering batching. At the same time, in the blast furnace raw material preparation process, the anthracite supplemented into the blast furnace and the sintering process is mixed and roll-crushed to obtain anthracite of 0-15 mm. Then, the anthracite supplemented into the sintering process is separated and mixed with the small particle coke powder and roll-crushed four times to 0-3 mm, and dried to obtain a mixed fuel. The 0-3 mm mixed fuel is screened to obtain large particle mixed fuel of 0.5-3 mm and sent to sintering. The small particle mixed fuel composed of fine coke powder <0.5 mm and fine coal powder <0.5 mm is mixed with anthracite and bituminous coal supplemented into the blast furnace and ground. After grinding to a proportion of <200 mesh accounting for 80%, it is subjected to bag dust removal and dried to a moisture content of <1.5% to obtain pulverized coal for blast furnace injection.

[0110] Among them, the heat quantity Q required for the target output of hot metal in the blast furnace process f = 15 GJ / t, the maximum blending amount C of bituminous coal = 35 kg, the minimum blending amount of large particle coke powder is γ*A = 360 kg, the proportion of large particle coke powder in coke is γ = 90%, then the total addition amount A of coke = 400 kg, and there is:

[0111] Q f = γ*A*Q1 + B*Q2 + C*Q3... (Formula 1)

[0112] In the formula, the calorific value Q1 of coke = 27.5 MJ / kg, the calorific value Q2 of anthracite = 27 MJ / kg, and the calorific value Q3 of bituminous coal = 25 MJ / kg.

[0113] It is calculated that B = 156.5 kg.

[0114] In addition, let the mass of fine coke powder in the small particle coke powder during the sintering process be X, and the mass of fine pulverized coal in the anthracite during the sintering process be Y. The total mass of the small particle coke powder and the fine pulverized coal is detected as Z = 16.2 kg, and the total heat is Q4 = 27.2 MJ / kg. Then, we have:

[0115] X + Y = Z...(Equation 2)

[0116] X * Q1 + Y * Q2 = Z * Q4...(Equation 3)

[0117] The solution is X = 5.2 kg and Y = 11 kg.

[0118] The mass of small particle coke powder in the coke is (1 - γ) * A = 40 kg. At the same time, it is known that the heat Q s required for the target output of sinter is 1.478 GJ / t. Then, we have

[0119] Q s = [(1 - γ) * A - X] * Q1 + (P - Y) * Q2...(Equation 4)

[0120] The calculated result is P = 14 kg.

[0121] Since the demand for coke in the blast furnace remains unchanged, the heat required for smelting 1 ton of hot metal also remains unchanged, and the adaptability of the blast furnace to bituminous coal is limited. When the mass of bituminous coal takes the maximum value, we have:

[0122] A' = A...(Equation 5)

[0123] C' = C...(Equation 6)

[0124] γ * A' * Q1 + Z * Q4 + (B' * Q2 + C' * Q3) = γ * A * Q1 + B * Q2 + C * Q3...(Equation 7)

[0125] The calculated result is B' = 140.2 kg.

[0126] [(1 - γ) * A' - X] * Q1 + (P' - Y) * Q2 = [(1 - γ) * A * Q1 + P * Q2]λ...(Equation 8)

[0127]

[0128] Among them, M = 30n 2 + 4.2n + 50.02 = 54 kg; M' = 30n' 2 + 4.2n' + 50.02 = 50.02 kg

[0129] In the formula,

[0130] Then, we have P' = 26.25 kg

[0131] According to the above calculations, under the new process conditions in the blast furnace process, A' = 400 kg, B' = 140.2 kg, C' = 35 kg, and under the new process conditions in the sintering process, P' = 26.25 kg.

[0132] It can be seen that considering the fuel consumption in the blast furnace and sintering, the consumption of coke and bituminous coal remains unchanged at 400 kg and 35 kg respectively, but the consumption of anthracite decreases from B + P = 170.5 kg in the traditional process to B' + P' = 166.7 kg in the new process.

[0133] Example 2

[0134] Repeat Example 1, except that the quality of bituminous coal in the blast furnace does not take the maximum value, then:

[0135] B″*Q2 + C″*Q3 = B′*Q2 + C′*Q3

[0136] Among them, C” ∈ (0~C'), and it is calculated that B” ∈ (172.6 kg~140.2 kg).

Claims

1. A fuel supply method with high fuel utilization rate, characterized in that: The method includes the following steps: 1) Fuel supply routes in the blast furnace process and the sintering process: Coke, bituminous coal, and anthracite are provided as fuels to the blast furnace process. Among them, large-particle coke powder in the coke is sent to the blast furnace process, and small-particle coke powder is sent to the sintering process. At the same time, anthracite is provided as a fuel supplement to the sintering process, and the fine coke powder in the small-particle coke powder and the fine coal powder in the anthracite in the sintering process are returned to the blast furnace process; 2) According to the heat required for the target output of hot metal in the blast furnace process and the blast furnace conditions, determine the minimum addition amount of large-particle coke powder and the maximum addition amount of bituminous coal; further determine the addition amount of anthracite in the blast furnace process based on the minimum addition amount of large-particle coke powder and the maximum addition amount of bituminous coal, and determine the total addition amount of coke according to the proportion of large-particle coke powder in the coke and the minimum addition amount of large-particle coke powder in the blast furnace; 3) According to the proportion of small-particle coke powder in the coke and the proportion of fine coke powder in the small-particle coke powder, determine the actual addition amount of small-particle coke powder added to the sintering process; according to the heat required for the target output of sinter in the sintering process and the actual addition amount of small-particle coke powder added to the sintering process, determine the addition amount of anthracite in the sintering process; further determine the actual addition amount of anthracite in the sintering process according to the proportion of fine coal powder in the anthracite required in the sintering process; 4) Mix the fine coke powder in step 2) and the fine coal powder in step 3) and then spray them into the blast furnace; and adjust the addition amounts of fuels in the blast furnace process and the sintering process according to the respective contents and calorific values of the fine coke powder and the fine coal powder, and then cycle steps 1)-4).

2. The method according to claim 1, wherein: The method further includes: 5) After the adjustment in step 4) is completed, compare the addition amounts of large-particle coke powder, bituminous coal, and anthracite in the blast furnace process under the new process conditions after adjustment, the addition amounts of small-particle coke powder and anthracite in the sintering process, with the addition amounts of large-particle coke powder, bituminous coal, and anthracite in the blast furnace process before adjustment, and the addition amounts of small-particle coke powder and anthracite in the sintering process before adjustment. When the change rate a ≤ 1%, stop the cycle; the change rate a of the fuel quality is the average of the change rates of the qualities of each fuel.

3. The method according to claim 2, wherein: Stop the cycle when the change rate a ≤ 0.5%.

4. The method according to any one of claims 1 to 3, characterized in that: The large-particle coke powder in step 1) is coke particles with a particle size ≥ 8 mm, and the small-particle coke powder in step 1) is coke particles with a particle size < 8 mm; and / or The fine coke powder in step 1) is coke particles with a particle size < 0.5 mm; and / or The fine coal powder in step 1) is coal powder particles with a particle size < 0.5 mm.

5. The method according to any one of claims 1-4, characterized in that: The minimum addition amount of the large-particle coke powder in step 2) is the mass of the coke as the skeleton in the blast furnace process; and / or The maximum addition amount of the bituminous coal in step 2) is the maximum mass of the bituminous coal that does not affect the operation according to the blast furnace conditions; The addition amount of anthracite in the blast furnace process and the total addition amount of coke in step 2) are: Q f = γ * A * Q1 + B * Q2 + C * Q3……(Equation 1) Where Q f is the total heat required in the blast furnace process; A is the total addition amount of coke; Q1 is the calorific value of coke; γ is the proportion of coke entering the blast furnace burden; B is the mass of anthracite added to the blast furnace; Q2 is the calorific value of anthracite; C is the mass of bituminous coal added to the blast furnace; Q3 is the calorific value of bituminous coal.

6. The method according to claim 5, characterized in that: The actual addition amount of small-particle coke powder and the actual addition amount of anthracite in the sintering process in step 3) are: Detect that the total mass of the fine coke powder in the small-particle coke powder and the fine coal powder in the anthracite is Z, and the total calorific value is Q4, then there is: X + Y = Z... (Equation 2) X * Q1 + Y * Q2 = Z * Q4... (Equation 3) The values of X and Y can be obtained according to Formula 2 and Formula 3. Then, in the sintering process: Q s = [(1 - γ) * A - X] * Q1 + (P - Y) * Q2... (Equation 4) In the formula, X is the content of fine coke powder in the small particle coke powder; Y is the content of fine coal powder in the anthracite; (1 - γ)*A - X is the actual addition amount of small particle coke powder in the sintering process, and P - Y is the actual addition amount of anthracite in the sintering process. Qs is the heat required for the target output of sinter in the sintering process, and P is the addition amount of anthracite in the sintering process.

7. The method according to claim 6, wherein: In step 4), according to the respective contents and calorific values of the fine coke powder and the fine coal powder, the adjustment of the addition amounts of fuels in the blast furnace process and the sintering process is as follows: Since the demand for coke in the blast furnace remains unchanged, the heat required for smelting 1 ton of hot metal also remains unchanged, and the adaptability of the blast furnace to bituminous coal is limited. When the quality of bituminous coal takes the maximum value, there is: A' = A... (Formula 5) C' = C... (Formula 6) γ*A'*Q1 + Z*Q4 + (B'*Q2 + C'*Q3) = γ*A*Q1 + B*Q2 + C*Q3... (Formula 7). In the formula, A' is the total mass of coke added in the blast furnace under the new process conditions; B' is the mass of anthracite added in the blast furnace under the new process conditions; C' is the mass of bituminous coal added in the blast furnace under the new process conditions. Meanwhile, the heat calculation in the sintering process is as follows: [(1 - γ)*A' - X]*Q1 + (P' - Y)*Q2 = [(1 - γ)*A*Q1 + P*Q2]λ... (Formula 8) In the formula, P' is the mass of anthracite added in the sintering under the new process conditions; M' is the fuel mass required per ton of sinter in the new process; M is the fuel mass required per ton of sinter in the original process. Among them, the calculation methods of M and M' are as follows: M = 30n 2 + 4.2n + 50.02……(Equation 10) In the formula, n is the proportion of small particle mixed fuel in the sintering fuel, %. According to the above formulas, the values of A', B', C', and P' can be calculated, that is, the masses of coke, anthracite, and bituminous coal added in the blast furnace under the new process conditions, and the mass of anthracite added to the sintering process.

8. The method according to claim 7, wherein: When the mass of bituminous coal added in the blast furnace does not take the maximum value, correspondingly: B”*Q2 + C”*Q3 = B'*Q2 + C'*Q3... (Formula 11) In the formula, C” is the mass of bituminous coal added in the blast furnace, and its value range is 0 to C'; B” is the mass of anthracite added in the blast furnace.

9. The method according to any one of claims 1 - 8, characterized in that: Specifically, step 1) is as follows: Feed the coke into the blast furnace raw material preparation process, screen to obtain large particle coke powder with a particle size of ≥8 mm and small particle coke powder with a particle size <8 mm. Send the large particle coke powder to the blast furnace batching, and send the small particle coke powder to the sintering batching; Mix and crush the anthracite added to the blast furnace and the sintering process to obtain anthracite with a particle size of 0 - 15 mm, separate the anthracite added to the sintering process, mix it with the small particle coke powder, and perform secondary crushing to 0 - 3 mm, and then dry to obtain the mixed fuel; Screen the 0 - 3 mm mixed fuel to obtain large particle mixed fuel with a particle size of 0.5 - 3 mm and send it to sintering. The small particle mixed fuel composed of fine coke powder with a particle size <0.5 mm and fine coal powder with a particle size <0.5 mm is mixed with the anthracite and bituminous coal added to the blast furnace, ground until the proportion of <200 mesh accounts for 80%, and then passed through bag dust removal to obtain the pulverized coal for blast furnace injection.

10. The method according to claim 9, wherein: Step 1) also includes hot air drying: performing hot air drying on the mixed fuel of 0 - 3 mm before screening; and / or Injecting hot air for drying while pulverizing the anthracite and bituminous coal mixture supplemented to the blast furnace.

11. The method according to any one of claims 1-10, characterized in that: Providing coke, bituminous coal and anthracite to the blast furnace process, providing anthracite to the sintering process, and returning the fine coke powder in the small particle coke powder and the fine pulverized coal in the anthracite in the sintering process to the blast furnace process in step 1) are all carried out in the blast furnace raw material preparation process.

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