Calculation method for unfired pulverized coal in blast furnace

Abstract

The invention provides a method for calculating unburned injection pulverized coal in a blast furnace. The method comprises the following steps: carrying out organic element analysis, combustion rate determination and CO2 reactivity determination experiments on blast furnace injection pulverized coal, determining physical property indexes of the injection pulverized coal (single or mixed pulverized coal), and calculating the carbon consumption of the injection pulverized coal in the blast furnace according to the three indexes, so as to obtain the amount of unburned pulverized coal in the blast furnace. After the method is applied, different injection pulverized coal can be evaluated, and basic data support is provided for adjustment of blast furnace operation. The method is easy and convenient to operate and high in operability, does not depend on a standard sample, calculates the amount of unburned pulverized coal by utilizing the physical properties of the injected pulverized coal, and has high reliability. Meanwhile, errors caused by sample non-uniformity can be eliminated through uniform mixing, sample division and repeated experiments, and the method has the advantages of simplicity and convenience in repeated experiments, low cost and the like.

Description

Technical Field

[0001] This invention pertains to blast furnace ironmaking technology and relates to a method for calculating unburned pulverized coal in a blast furnace, particularly a method for calculating unburned pulverized coal injected into a blast furnace. Background Technology

[0002] At present, pulverized coal injection technology for blast furnaces has been widely used. After the pulverized coal enters the blast furnace, it will first burn at the tuyere. The remaining part will rise with the gas. During its ascent, most of it will react with CO2 in the gas to generate CO, and then participate in the reduction reaction of oxides. The other unreacted part will enter the gas ash at the top of the furnace with the gas, or adhere to the furnace charge to participate in the reaction or enter the slag.

[0003] Currently, it is difficult to directly distinguish the carbon introduced by coke powder and unburned coal powder in gas ash and blast furnace slag. The main methods used are microscopic component analysis, Raman spectroscopy, and X-ray diffraction. Microscopic component analysis is highly subjective, with different researchers using different formulas, and there is no universally accepted standard formula. Furthermore, sample inhomogeneity has a significant impact on the results, leading to large fluctuations in the calculated results. Raman spectroscopy can only semi-quantitatively determine the trend of coal powder utilization under different blast furnace operating conditions, but it cannot quantitatively calculate the coal powder utilization rate. X-ray diffraction is more scientific, but it is highly dependent on the selection of standard samples. When the coal type, coke blending structure, etc., change in on-site production, the selection of standard samples becomes difficult, and the determination of the average stacking thickness Lc value of standard samples is costly and difficult.

[0004] Therefore, finding a more accurate method for calculating unburned pulverized coal in blast furnaces and solving the aforementioned technical problems in existing calculation methods has become one of the urgent issues for many front-line researchers and blast furnace smelting enterprises in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for calculating unburned pulverized coal in a blast furnace, particularly a method for calculating unburned injected pulverized coal in a blast furnace. The calculation method provided by the present invention is simple to operate, highly operable, does not rely on standard samples, and has strong reliability. Furthermore, errors caused by sample inhomogeneity can be eliminated through mixing, sample reduction, and repeated experiments, offering advantages such as simple repeatable experiments and low cost.

[0006] This invention provides a method for calculating unburned pulverized coal injected into a blast furnace, comprising the following steps:

[0007] 1) Elemental analysis was performed on the pulverized coal samples used in the blast furnace to obtain the contents of five elements: C, H, O, N, and S.

[0008] 2) Under oxygen atmosphere, the pulverized coal sample is subjected to combustion reaction at high temperature. After the reaction is completed, the contents of CO, CO2, O2 and N2 in the gas after the reaction are measured. Combined with the elemental analysis results in step 1), the combustion rate η of pulverized coal is calculated.

[0009] 3) The reactivity of pulverized coal with CO2 was determined from the pulverized coal samples, and the CO2 reactivity CRI of the pulverized coal was calculated. coal ;

[0010] 4) The pulverized coal combustion rate η and the pulverized coal reactivity CRI with CO2 obtained in the above steps are compared. coal After recalculation, the unburned pulverized coal ratio WR of the pulverized coal injection was obtained. coal .

[0011] Preferably, the pulverized coal sample is dried pulverized coal.

[0012] The purity of the oxygen is greater than or equal to 99.2%.

[0013] Preferably, the temperature of the combustion reaction is the blast furnace blast temperature.

[0014] Preferably, the pulverized coal combustion rate is specifically the average pulverized coal combustion rate.

[0015] Preferably, the average combustion rate of the pulverized coal is obtained by repeatedly performing the pulverized coal combustion rate experiment in step 2), obtaining multiple pulverized coal combustion rates, and taking the average value.

[0016] The number of repetitions is ≥10 times.

[0017] Preferably, the process of determining the reactivity of pulverized coal with CO2 includes the following steps:

[0018] Under a protective atmosphere, the pulverized coal sample was heated until it reached a constant weight m1, and then heated to the experimental temperature. The protective atmosphere was then replaced with a mixture of CO2 and CO, and the temperature was maintained until it reached a constant weight m2.

[0019] Preferably, the heating temperature is 850~950℃;

[0020] The experimental temperature was the blast furnace blast temperature.

[0021] Preferably, in the mixed atmosphere, by volume, CO2:CO = blast furnace gas utilization rate: (100% - blast furnace gas utilization rate).

[0022] Preferably, in step 3), the calculation formula is specifically: CRI coal = (m1-m2) / m1×100%.

[0023] Preferably, the formula for the recalculation is as follows:

[0024] Unburned coal powder ratio WR coal = (100% - η) × (100% - CRI) coal );

[0025] Among them, WR coal ω represents the unburned pulverized coal ratio. t % η is the combustion rate of pulverized coal at the tuyeres, ω t % for CRI coal -CO2 reactivity of pulverized coal, ω t % / h.

[0026] This invention provides a method for calculating the amount of unburned pulverized coal injected into a blast furnace, comprising the following steps: First, elemental analysis is performed on a pulverized coal sample used in the blast furnace to obtain the contents of five elements: C, H, O, N, and S. Then, under an oxygen atmosphere, the pulverized coal sample is subjected to a combustion reaction at high temperature. After the reaction is completed, the contents of CO, CO2, O2, and N2 in the gas produced are measured. Combined with the elemental analysis results from step 1), the combustion rate η of the pulverized coal is calculated. Finally, the reactivity of the pulverized coal with CO2 is measured, and the CO2 reactivity CRI of the pulverized coal is calculated. coal Finally, the pulverized coal combustion rate η and the pulverized coal reactivity CRI with CO2 obtained from the above steps are compared. coal After recalculation, the unburned pulverized coal ratio WR of the pulverized coal injection was obtained. coal Compared with existing technologies, this invention specifically designs a calculation method for unburned pulverized coal in a blast furnace. This method calculates the amount of unburned injected pulverized coal in a blast furnace under different blast temperatures by determining the physical properties of the pulverized coal. The calculation method provided by this invention is simple to operate, highly operable, does not rely on standard samples, and has strong reliability. Furthermore, errors caused by sample inhomogeneity can be eliminated through mixing, sample reduction, and repeated experiments, offering advantages such as simple repeatability and low cost.

[0027] This invention determines the physical properties of pulverized coal (single or mixed types) by conducting organic element analysis, combustion rate determination, and CO2 reactivity testing on pulverized coal injected into a blast furnace. These three properties are then used to calculate the carbon consumption within the blast furnace, thus determining the amount of unburned pulverized coal. This method can be applied to evaluate different types of pulverized coal, providing fundamental data support for adjusting blast furnace operations. The method is simple to operate, highly operable, and does not rely on standard samples. It utilizes the physical properties of the pulverized coal itself to calculate the amount of unburned pulverized coal, exhibiting high reliability. Furthermore, errors caused by sample inhomogeneity can be eliminated through mixing, sample reduction, and repeated experiments, offering advantages such as ease of repetitive experiments and low cost.

[0028] The calculation method provided by this invention is simple, practical, and highly operable. It utilizes the physical properties of pulverized coal for calculation, neglecting only the unburned pulverized coal that adheres to the surface of the furnace charge and does not participate in the reduction reaction before entering the slag. Since the content of unburned pulverized coal in blast furnace slag is low and it mainly enters the blast furnace top dust, it has little impact on the calculation results. The calculation has good accuracy and is of great guiding significance for the comprehensive evaluation of pulverized coal injection in blast furnaces. Detailed Implementation

[0029] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention and not for limiting the claims of the present invention.

[0030] All terms and abbreviations used in this invention are conventional terms and abbreviations in the field. Each term and abbreviation is clear and distinct in its relevant application area, and those skilled in the art can understand it clearly, accurately, and uniquely based on the terms and abbreviations.

[0031] This invention provides a method for calculating unburned pulverized coal injected into a blast furnace, comprising the following steps:

[0032] 1) Elemental analysis was performed on the pulverized coal samples used in the blast furnace to obtain the contents of five elements: C, H, O, N, and S.

[0033] 2) Under oxygen atmosphere, the pulverized coal sample is subjected to combustion reaction at high temperature. After the reaction is completed, the contents of CO, CO2, O2 and N2 in the gas after the reaction are measured. Combined with the elemental analysis results in step 1), the combustion rate η of pulverized coal is calculated.

[0034] 3) The reactivity of pulverized coal with CO2 was determined from the pulverized coal samples, and the CO2 reactivity CRI of the pulverized coal was calculated. coal ;

[0035] 4) The pulverized coal combustion rate η and the pulverized coal reactivity CRI with CO2 obtained in the above steps are compared. coal After recalculation, the unburned pulverized coal ratio WR of the pulverized coal injection was obtained. coal .

[0036] In this invention, there is no sequential order between step 3) and steps 1) and 2).

[0037] The present invention first performs elemental analysis on pulverized coal samples used in blast furnaces to obtain the contents of five elements: C, H, O, N and S.

[0038] In this invention, the pulverized coal sample is preferably dried pulverized coal.

[0039] In this invention, the pulverized coal sample is subjected to combustion reaction at high temperature under an oxygen atmosphere. After the reaction is completed, the contents of CO, CO2, O2 and N2 in the gas after the reaction are measured. Combined with the elemental analysis results in step 1), the combustion rate η of the pulverized coal is calculated.

[0040] This invention involves filling the equipment with oxygen and then using the pressure difference to send pulverized coal into a high-temperature furnace preheated with oxygen, where it falls freely. The combustion rate of the pulverized coal is measured during this time. The specific steps are as follows: first, oxygen is introduced, then a solenoid valve is used to isolate the sample, creating a pressure difference before and after the sample. Once the test begins, the solenoid valve opens, and the pressure difference propels the pulverized coal sample to the upper part of the high-temperature furnace. The pulverized coal then falls freely. The pressure is typically around 0.4 MPa in the high-pressure section and around 0.2 MPa in the low-pressure section. The reaction time is mainly the time it takes for the pulverized coal to fall freely, while the pressure primarily serves to deliver it to the upper part of the high-temperature furnace.

[0041] In this invention, the purity of the oxygen is preferably greater than or equal to 99.2%, greater than or equal to 99.3%, and greater than or equal to 99.4%.

[0042] In this invention, the preferred temperature for the combustion reaction is the blast furnace blast temperature, which can be 1200~1250℃, specifically 1200℃. In this invention, the actual blast furnace blast temperature can be used as the reaction temperature. Generally, the blast temperature is below 1200℃, 1200~1250℃ is conventional, and it can reach above 1250℃. Adjustments can be made according to the specific process conditions.

[0043] In this invention, the pulverized coal combustion rate is preferably the average pulverized coal combustion rate.

[0044] In this invention, the average combustion rate of the pulverized coal is preferably obtained by repeatedly performing the pulverized coal combustion rate experiment in step 2) to obtain multiple pulverized coal combustion rates and taking the average value.

[0045] In this invention, the number of repetitions is preferably ≥10 times, more preferably ≥11 times, and even more preferably ≥12 times.

[0046] In this invention, the calculation method for the pulverized coal combustion rate η is preferably performed by a corresponding device. Specifically, the pulverized coal combustion rate η of this invention is calculated using a customized pulverized coal combustion simulation test device designed and commercially available from Beijing University of Science and Technology.

[0047] This invention further measures the reactivity of pulverized coal with CO2 in pulverized coal samples, and calculates the CRI of CO2 reactivity of pulverized coal. coal .

[0048] In this invention, the process of determining the reactivity of pulverized coal with CO2 preferably includes the following steps:

[0049] Under a protective atmosphere, the pulverized coal sample was heated until it reached a constant weight m1, and then heated to the experimental temperature. The protective atmosphere was then replaced with a mixture of CO2 and CO, and the temperature was maintained until it reached a constant weight m2.

[0050] In this invention, the heating temperature is preferably 850~950℃, more preferably 870~930℃, even more preferably 890~910℃, and specifically 900℃.

[0051] In this invention, the experimental temperature is preferably the blast furnace blast temperature. The actual blast furnace blast temperature can be used as the reaction temperature. Generally, the blast temperature is below 1200℃, 1200~1250℃ is conventional, and it can reach above 1250℃. Adjustments can be made according to the specific process conditions.

[0052] In this invention, an inert gas is introduced to remove volatiles from pulverized coal. The reaction temperature is the blast furnace temperature, which can be determined based on the actual blast furnace temperature conditions. Here, blast furnace temperature refers to the temperature of the hot air, specifically the temperature of the heated or oxygen-enriched air inside the hot blast stove.

[0053] In this invention, in the mixed atmosphere, preferably by volume, CO2:CO = blast furnace gas utilization rate: (100% - blast furnace gas utilization rate). Here, blast furnace gas utilization rate is a well-known technical parameter for blast furnaces, calculated based on the actual composition of the blast furnace top gas, and is a common algorithm in the field, though it varies depending on the specific blast furnace.

[0054] Finally, this invention compares the pulverized coal combustion rate η and the pulverized coal reactivity CRI with CO2 obtained from the above steps. coal After recalculation, the unburned pulverized coal ratio WR of the pulverized coal injection was obtained. coal .

[0055] In this invention, the preferred formula for calculation in step 3) is CRI. coal = (m1-m2) / m1×100%.

[0056] In this invention, the formula for the recalculation is preferably:

[0057] Unburned coal powder ratio WR coal = (100% - η) × (100% - CRI) coal );

[0058] Among them, WR coal ω represents the unburned pulverized coal ratio.t % η is the combustion rate of pulverized coal at the tuyeres, ω t % for CRI coal -CO2 reactivity of pulverized coal, ω t % / h.

[0059] The calculation method provided by this invention is simple, practical, and highly operable. It utilizes the physical properties of pulverized coal for calculation, neglecting only the unburned pulverized coal that adheres to the surface of the furnace charge and does not participate in the reduction reaction before entering the slag. Since the content of unburned pulverized coal in blast furnace slag is low and it mainly enters the blast furnace top dust, it has little impact on the calculation results. The calculation has good accuracy and is of great guiding significance for the comprehensive evaluation of pulverized coal injection in blast furnaces.

[0060] To complete and refine the overall technical solution and better ensure the accuracy and stability of the calculation method for unburned pulverized coal injected into the blast furnace, the above-mentioned calculation method for unburned pulverized coal injected into the blast furnace may specifically include the following steps:

[0061] S1: Dry the pulverized coal, reduce its volume to obtain multiple samples for testing experiments, and keep them for future use.

[0062] S2: Take a sample of pulverized coal and use an organic element analyzer to determine the content of five elements, C, H, O, N and S, in the pulverized coal.

[0063] S3: Take a sample of pulverized coal and conduct a pulverized coal combustion rate experiment. During the experiment, adjust the combustion temperature as needed. The combustion rate is measured in an atmosphere with an O2 content ≥ 99.2% (since the combustion speed of pulverized coal is much greater than that of coke, the combustion reaction of pulverized coal at the tuyeres is less than one second, which can be considered instantaneous. Although the oxygen content in the blast furnace tuyeres is generally less than 30%, the amount of oxygen is sufficient for the pulverized coal to burn completely. From the perspective of reaction time and oxygen content, the combustion reaction of pulverized coal has good reaction conditions. Therefore, an excess of pure oxygen is used in the measurement, and the experiment is conducted by using pure oxygen flow to assist the pulverized coal through the high-temperature zone using pressure difference, in order to simulate the conditions of sufficient oxygen and short reaction time in the blast furnace). After the reaction is completed, collect the gas after the reaction into the gas collecting bottle and close the gas collecting bottle valve to prevent oxygen pollution in the reactor. Analyze the CO, CO2, O2, and N2 contents in the gas collecting bottle. Combined with the results of the organic element analysis of pulverized coal, calculate the pulverized coal combustion rate. Repeat the pulverized coal combustion rate experiment ≥ 10 times to obtain the average pulverized coal combustion rate.

[0064] S4: Take a sample of pulverized coal and use a thermogravimetric analyzer to determine the reactivity of pulverized coal with CO2. First, heat the sample under an inert atmosphere until the pulverized coal evaporates its moisture and volatiles (the volatiles and moisture evaporate during the combustion process at the tuyeres; the pulverized coal in step S3 has also evaporated its volatiles and moisture after drying and combustion, so this step measures the reactivity of pulverized coal without volatiles and moisture with CO2). After maintaining a constant weight, record the mass of the pulverized coal as m1. Then heat the sample to the experimental temperature (which can be set according to experimental requirements or with reference to the on-site blast temperature). After the temperature stabilizes, switch the inert gas to an experimental atmosphere of CO2: CO = blast furnace gas utilization rate: (100% - blast furnace gas utilization rate). Maintain the temperature until the mass of the pulverized coal is constant, and record the mass of the pulverized coal as m2. Calculate the CRI (reactivity ratio) of the pulverized coal with CO2. coal = (m1-m2) / m1×100%;

[0065] S5: Calculation formulas related to unburned pulverized coal:

[0066] Unburned coal powder ratio WR coal = (100%-η)×(100%-CRI coal )

[0067] in:

[0068] WR coal -Unburned coal powder ratio, ω t %

[0069] η - Combustion rate of pulverized coal injection tuyere, ω t %

[0070] CRI coal -CO2 reactivity of pulverized coal, ω t % / h.

[0071] The present invention provides a method for calculating unburned pulverized coal in a blast furnace. This method, which determines the amount of unburned injected pulverized coal in a blast furnace under different blast temperatures based on the physical properties of the pulverized coal, is simple to operate, highly operable, does not rely on standard samples, and possesses strong reliability. Furthermore, errors caused by sample inhomogeneity can be eliminated through mixing, sample reduction, and repeated experiments, offering advantages such as ease of repeating experiments and low cost.

[0072] This invention determines the physical properties of pulverized coal (single or mixed types) by conducting organic element analysis, combustion rate determination, and CO2 reactivity testing on pulverized coal injected into a blast furnace. These three properties are then used to calculate the carbon consumption within the blast furnace, thus determining the amount of unburned pulverized coal. This method can be applied to evaluate different types of pulverized coal, providing fundamental data support for adjusting blast furnace operations. The method is simple to operate, highly operable, and does not rely on standard samples. It utilizes the physical properties of the pulverized coal itself to calculate the amount of unburned pulverized coal, exhibiting high reliability. Furthermore, errors caused by sample inhomogeneity can be eliminated through mixing, sample reduction, and repeated experiments, offering advantages such as ease of repetitive experiments and low cost.

[0073] The calculation method provided by this invention is simple, practical, and highly operable. It utilizes the physical properties of pulverized coal for calculation, neglecting only the unburned pulverized coal that adheres to the surface of the furnace charge and does not participate in the reduction reaction before entering the slag. Since the content of unburned pulverized coal in blast furnace slag is low and it mainly enters the blast furnace top dust, it has little impact on the calculation results. The calculation has good accuracy and is of great guiding significance for the comprehensive evaluation of pulverized coal injection in blast furnaces.

[0074] To further illustrate the present invention, the following describes in detail a method for calculating unburned pulverized coal in a blast furnace, in conjunction with embodiments. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. They are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0075] Example

[0076] S1: Dry the pulverized coal, reduce its volume, take four samples, each weighing 50g, three of which will be used for testing, and one will be kept for future use.

[0077] S2: Take a sample of pulverized coal and use an organic element analyzer to determine the content of five elements, C, H, O, N and S, in the pulverized coal.

[0078] S3: Take a sample of pulverized coal and conduct a pulverized coal combustion rate experiment. During the experiment, adjust the combustion temperature as needed. The combustion rate is measured in an atmosphere with an O2 content ≥ 99.2% (since the combustion speed of pulverized coal is much greater than that of coke, the combustion reaction of pulverized coal at the tuyeres is less than one second, which can be considered as instantaneous. Although the oxygen content in the blast furnace tuyeres is generally less than 30%, the amount of oxygen is sufficient to completely burn the pulverized coal. From the perspective of reaction time and oxygen content, the combustion reaction of pulverized coal has good reaction conditions. Therefore, an excess of pure oxygen is used in the measurement, and the experiment is conducted by using pure oxygen flow to assist the pulverized coal through the high-temperature zone using pressure difference, in order to simulate the conditions of sufficient oxygen and short reaction time in the blast furnace). After the reaction is completed, collect the gas after the reaction into the gas collecting bottle and close the gas collecting bottle valve to prevent oxygen pollution in the reactor. Analyze the CO, CO2, O2, and N2 contents in the gas collecting bottle. Combined with the results of the organic element analysis of pulverized coal, calculate the pulverized coal combustion rate. Repeat the pulverized coal combustion rate experiment ≥ 10 times to obtain the average pulverized coal combustion rate.

[0079] S4: Take a sample of pulverized coal and use a thermogravimetric analyzer to determine the reactivity of pulverized coal with CO2. First, heat the sample to 900℃ under an inert atmosphere until the pulverized coal evaporates its moisture and volatiles (the volatiles and moisture have already evaporated during the combustion process at the tuyeres; the pulverized coal in step S3 has also evaporated its volatiles and moisture after drying and combustion, so this step measures the reactivity of pulverized coal without volatiles and moisture with CO2). After maintaining a constant weight, record the mass of the pulverized coal as m1. Then, heat the sample to the experimental temperature (which can be set according to experimental requirements or with reference to the on-site blast temperature). After the temperature stabilizes, switch the inert gas to an experimental atmosphere of CO2: CO = blast furnace gas utilization rate: (100% - blast furnace gas utilization rate). Maintain the temperature until the mass of the pulverized coal is constant, and record the mass of the pulverized coal as m2. Calculate the CRI (reactivity ratio) of the pulverized coal with CO2. coal = (m1-m2) / m1×100%;

[0080] S5: Calculation formulas related to unburned pulverized coal:

[0081] Unburned coal powder ratio WR coal = (100%-η)×(100%-CRI coal )

[0082] in:

[0083] WR coal -Unburned coal powder ratio, ω t %

[0084] η - Combustion rate of pulverized coal injection tuyere, ω t %

[0085] CRIcoal -CO2 reactivity of pulverized coal, ω t % / h.

[0086] Organic element content analysis, combustion rate at the tuyere of pulverized coal at 1200℃ (experimental conditions can be adjusted according to actual air temperature), and CO2 reactivity of pulverized coal at 1200℃ (experimental conditions can be adjusted according to actual air temperature) were conducted on three types of pulverized coal (A, B, and C). (For ease of gas mixing during the experiment, the experimental atmosphere was 50% CO2 + 50% CO). See Table 1, which shows the organic element analysis, combustion rate, and CO2 reactivity of the pulverized coal in the embodiments of this invention.

[0087] Table 1

[0088]

[0089] See Table 2, which shows the calculation results of the unburned coal powder rate in the embodiments of the present invention.

[0090] Table 2

[0091]

[0092] As can be seen from the table above, this invention analyzes the organic element content of pulverized coal, then determines the combustion rate of pulverized coal at the blast outlet under different air temperatures, and finally measures the CO2 reactivity of pulverized coal at different air temperatures using a thermogravimetric analyzer. From this, the unburned coal powder rate (WR) can be calculated. coal .

[0093] The above provides a detailed description of the calculation method for unburned pulverized coal injected into a blast furnace provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of this invention, including the best mode, and also to enable any person skilled in the art to practice this invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the wording of the claims, or if they include equivalent structural elements that are not substantially different from the wording of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for calculating unburned pulverized coal injected into a blast furnace, characterized in that, Includes the following steps: 1) Elemental analysis was performed on the pulverized coal samples used in the blast furnace to obtain the contents of five elements: C, H, O, N, and S. 2) Under oxygen atmosphere, the pulverized coal sample is subjected to combustion reaction at high temperature. After the reaction is completed, the contents of CO, CO2, O2 and N2 in the gas after the reaction are measured. Combined with the elemental analysis results in step 1), the combustion rate η of pulverized coal is calculated. 3) The reactivity of pulverized coal with CO2 was determined from the pulverized coal samples, and the CO2 reactivity CRI of the pulverized coal was calculated. coal ; 4) The pulverized coal combustion rate η and the pulverized coal reactivity CRI with CO2 obtained in the above steps are compared. coal After recalculation, the unburned pulverized coal ratio WR of the pulverized coal injection was obtained. coal .

2. The calculation method according to claim 1, characterized in that, The pulverized coal sample is specifically dried pulverized coal. The purity of the oxygen is greater than or equal to 99.2%.

3. The calculation method according to claim 1, characterized in that, The temperature of the combustion reaction is the blast furnace blast temperature.

4. The calculation method according to claim 1, characterized in that, The pulverized coal combustion rate is specifically the average pulverized coal combustion rate.

5. The calculation method according to claim 4, characterized in that, The average combustion rate of the pulverized coal is specifically obtained by repeating the pulverized coal combustion rate experiment in step 2) to obtain multiple pulverized coal combustion rates and taking the average value. The number of repetitions is ≥10 times.

6. The calculation method according to claim 1, characterized in that, The process for determining the reactivity of pulverized coal with CO2 includes the following steps: Under a protective atmosphere, the pulverized coal sample was heated until it reached a constant weight m1, and then heated to the experimental temperature. The protective atmosphere was then replaced with a mixture of CO2 and CO, and the temperature was maintained until it reached a constant weight m2.

7. The calculation method according to claim 6, characterized in that, The heating temperature is 850~950℃; The experimental temperature was the blast furnace blast temperature.

8. The calculation method according to claim 6, characterized in that, In the mixed atmosphere, by volume, CO2:CO = blast furnace gas utilization rate: (100% - blast furnace gas utilization rate).

9. The calculation method according to claim 6, characterized in that, In step 3), the specific formula for calculation is: CRI coal = (m1-m2) / m1×100%.

10. The calculation method according to claim 1, characterized in that, The formula for the recalculation is as follows: Unburned coal powder ratio WR coal = (100% - η) × (100% - CRI) coal ); Among them, WR coal ω represents the unburned pulverized coal ratio. t % η is the combustion rate of pulverized coal at the tuyeres, ω t % for CRI coal -CO2 reactivity of pulverized coal, ω t % / h.

Images