JP5553145B2 - Calculating method, device, program for carbon usage in blast furnace and method for evaluating validity of normal RAR - Google Patents

Description

  The present invention relates to a technique for calculating the total amount of carbon required to reduce various iron oxide raw materials such as iron ore in a shaft type reduction furnace such as a blast furnace, and a published index of reducing material ratio (RAR). On the other hand, it relates to a technique for objectively evaluating the validity.

  As an index for evaluating the amount of carbon material used in blast furnace operation, an index called RAR (Reduction Agent Ratio) is generally disclosed. The detailed calculation logic about the calculation method of RAR [unit: kg / pig-ton] differs depending on each company and each blast furnace factory. However, the basic idea of the calculation is that the consumption per unit time [for example, kg / min] of carbonaceous materials represented by coke, pulverized coal, LNG, etc. For example, it is obtained by dividing by (pig-ton / min) (using the denominator) (hereinafter referred to as normal RAR). In other words, the normal RAR expresses the efficiency of using the carbonaceous material for producing the unit yield, and if the normal RAR is high, the usage efficiency of the carbonaceous material is low, and if the normal RAR is low, It shows that the usage efficiency is high. In general, in addition to the normal RAR, the output [pig-ton / day] of each blast furnace is also published on a monthly average, so the amount [kg / day] of the carbon material used by each blast furnace is (normal RAR). X output amount).

  In addition to the normal RAR, there is no known index indicating the amount of total carbon material used in the blast furnace. Non-Patent Document 1 clearly states various ideas and models related to blast furnace operation, but the normal RAR, which was called “fuel ratio” at that time, is treated as an index that is naturally known to blast furnace personnel. Even the calculation method is not described. Chapter 6 of Non-Patent Document 1 describes the concept of blast furnace operation theory based on the heat balance and mass balance in the blast furnace, but does not mention any problems of normal RAR calculation.

Akitoshi Shigemi, “Shoyo Handbook” Jishinshokan, 1979, Chapter 6

  First, in the normal RAR, there is a possibility that the calculation result varies depending on the blast furnace because the calculation method is arbitrary due to the difference in the calculation method of the carbon material charging amount at each factory. For example, since the types of reducing materials are diversified, such as coke, pulverized coal, LNG, heavy oil, coal-containing agglomerates, etc., coal materials with different types and physical properties are unified and evaluated side by side. It is thought that it will become more and more difficult to devise a calculation method that can be used. In other words, the essential problem of the normal RAR calculation method is that carbon sources such as charged carbonaceous material (solid), heavy oil (liquid), carbon-containing reducing gas (gas) and the like are completely different. Nevertheless, it is considered that the normal RAR is calculated based on the “conditions for supplying various carbon sources to the blast furnace (charging / blowing) conditions”.

  Furthermore, the normal RAR cannot essentially index the amount of “carbon” used in the carbonaceous material. Usually, the numerator for calculating the RAR uses the simple mass of the carbonaceous material, so the amount of “carbon” actually used varies greatly depending on the type of the carbonaceous material used. For example, the mass of coke and pulverized coal is the mass that contains impurities other than carbon, such as ash, moisture content, crystal moisture, and various binding elements, and the content ratio varies greatly depending on the type of carbonaceous material. is there. In other words, even if the mass of the same carbonaceous material, the amount of carbon contained therein varies greatly depending on the raw material conditions, season, period, etc. of each company / factory. In particular, for pulverized coal, the carbon content varies greatly depending on the amount of volatile components and the amount of ash components contained therein, so it is highly possible that the actual amount of carbon used cannot be reflected by simple mass comparison.

  Needless to say, in actual operation of the blast furnace, it is very important to accurately grasp the amount of “carbon” actually supplied to the blast furnace in thermal management and temperature management of the blast furnace. However, there is a limit in estimating an accurate amount of “carbon” using the analysis value of various carbonaceous materials from the calculated value of normal RAR calculated from simple mass comparison. For example, the carbon content of a certain carbonaceous material is based on a fixed carbon content analysis value of a sampled sample. Therefore, in order to ensure its representativeness, many analysis results must be combined. As the brands and types of charcoal materials diversify, determining these accurate analytical values will be a heavy workload, and its reliability will be questioned to the end. In this way, in terms of blast furnace operation management, if the carbon supply is managed based only on the normal RAR, it can lead to unexpected heat shortages and excessive heat, and there is also a risk that can lead to major operational troubles. There is.

Furthermore, in the future, it will be necessary to objectively evaluate the amount of “carbon” actually used in the international movement of reducing CO ₂ gas emissions. There is also sex. In addition, there is a problem that it is extremely difficult to verify whether the declared normal RAR is an appropriate value reflecting the actual operation.

  In addition, since the normal RAR is calculated from the simple mass of various carbon materials, it is assumed that the carbon tax will be imposed in the future depending on the amount of the normal RAR. There is no denying that there is a possibility of distortion in the idea. For example, based on the concept of normal RAR calculation, when selecting a pulverized coal type for tuyere blowing, calculation using a pulverized coal with a high carbon content ratio usually results in a lower RAR. In other words, when considering the use of inferior coal with a lot of impurities, it would be negative even if the tax benefits of normal RAR were evaluated, and in addition, considering that the stability of blast furnace operation was also negative, we dare The advantage of using fresh coal is completely lost. In the future, in order to make effective use of charcoal resources globally, it will be important to establish technology that makes use of inferior coal with a low carbon content ratio even in blast furnaces. After that, it will be difficult to evoke such technological development motivation.

  The present invention has been made in view of such points, and avoids the use of the supply side (charging / blowing) conditions of the carbon-containing raw material in calculating the actual carbon amount used in the blast furnace. It aims at providing the method of quantifying the usage-amount of "carbon" in a blast furnace from the blast flow condition from a gas and the gas component analysis conditions in a furnace top.

The calculation method of carbon usage in the blast furnace of the present invention is based on the total flow rate of the inert gas blown into the blast furnace and the analysis value of the inert gas volume fraction of the exhaust gas at the top of the furnace. Obtain the carbon discharge volume from the furnace top exhaust gas from the carbon dioxide volume fraction and the carbon monoxide volume fraction of the furnace top exhaust gas, and use the total carbon used in the blast furnace or the reducing material A ratio (RAR) is calculated.
Another feature of the method for calculating the amount of carbon used in the blast furnace of the present invention is that nitrogen is used as the inert gas.
Usually validity evaluation method of RAR of the present invention, by comparing the RAR calculated by the calculation method of the carbon amount in the blast furnace of the present invention, a normal RAR calculated from the amount of supply carbonaceous material to the blast furnace, It is characterized by evaluating the validity of the normal RAR.
The apparatus for calculating the amount of carbon used in the blast furnace according to the present invention calculates the total top exhaust gas flow rate from the total inert gas flow rate injected into the blast furnace furnace and the inert gas volume fraction analysis value of the top exhaust gas. Obtain the carbon discharge volume from the furnace top exhaust gas from the carbon dioxide volume fraction and the carbon monoxide volume fraction of the furnace top exhaust gas, and use the total carbon used in the blast furnace or the reducing material An arithmetic means for calculating the ratio (RAR) is provided.
The program of the present invention obtains the total exhaust gas flow rate from the total flow rate of the inert gas blown into the blast furnace furnace and the inert gas volume fraction analysis value of the exhaust gas at the top of the furnace. From the carbon dioxide volume fraction and carbon monoxide volume fraction of the gas, the carbon emission amount from the furnace top exhaust gas is calculated, and the total carbon usage amount used in the blast furnace or the reducing material ratio (RAR) is calculated. Have the computer execute the process.

  According to the present invention, the tuyere is relatively easy to standardize the measurement method without relying on the supply side (charging / blowing) conditions of the carbon-containing raw material, which is difficult to standardize the calculation and lacks reliability. The total carbon amount used in the operation of the blast furnace can be quantified from the flow rate of air from the top, the volume fraction measurement data of the top gas component in the furnace top collecting pipe, and the like. And since the amount of real carbon supplied to the blast furnace can be quantified, the accuracy of heat and temperature management in blast furnace operation can be greatly improved.

It is a figure which shows schematic structure of the calculation apparatus of the carbon usage-amount in a blast furnace. It is a characteristic view for demonstrating the calculation example of the calculation method of the carbon usage-amount in an Example. It is a characteristic view for demonstrating the relationship between RAR of this invention and normal RAR.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
In blast furnace operation, high temperature gas containing oxygen is fed from a plurality of tuyere arranged in the circumferential direction at the lower part of the furnace, and incomplete combustion occurs in the blast furnace furnace to generate CO gas. And while this CO gas rises to the furnace top, a part of it reduces various iron ores that descend from the upper part of the furnace, and is discharged from the furnace top as CO ₂ gas at the furnace top. (If the reduction reaction of wustite FeO is taken as an example, FeO + CO → Fe + CO ₂ ). In addition, the generation source of CO gas is not only due to such incomplete combustion before the tuyere, but CO ₂ gas once contributed to the reduction is again combined with the solid carbon in the furnace (CO ₂ + C (This is called the 2CO Sollos reaction), and the reaction of CO gas regeneration is also involved. When this CO gas contributes again to iron ore reduction, CO ₂ gas is regenerated.

Thus, when focusing on the “carbon” gas consumed in the blast furnace, it becomes one of CO gas due to incomplete combustion before the tuyere, CO ₂ gas due to iron ore reduction reaction, and CO gas due to the Sollos reaction. I understand that. Eventually, most of it will be discharged out of the furnace as furnace top CO gas or furnace top CO ₂ gas. Therefore, it is very important to quantify the amount of CO gas in the furnace top gas and the amount of CO ₂ gas in the furnace top gas in determining the amount of carbon used in the blast furnace (the amount of carbon used per unit time). is there.

As for the contents of the present invention, as the inert gas, the most blown-in amount is used. As a representative example, generally used nitrogen, the total gas flow at the top of the furnace, the top CO gas, the top CO ₂ gas, etc. are discharged. A method for calculating the flow rate will be described, and then a method for estimating the total amount of carbon used in the blast furnace will be described.

Expression (1) is an expression for estimating the total O ₂ flow rate O2 _{all, blow} blown from the tuyere. The total O ₂ flow rate O2 _{all, blow} indicates the sum of the blowing flow rate V _b and the oxygen-enriched flow rate O2. In Formula (1), since the ventilation flow rate _Vb is a flow rate in the standard state of air, it is multiplied by an oxygen content ratio in air of 0.21. Moreover, since the unit of the oxygen enrichment flow rate O2 is conventionally [Nm ³ / hr], it is divided by 60 [min]. Expression (2) is an expression for estimating the total N ₂ flow rate N2 _{all, blow} blown from the tuyere. From equation (1) and (2), can be approximated oxygen feather preoral blowing gas, nitrogen respective volume ratio x _{O2, blow,} the x _{N2, blow.} The result is Formula (3) and Formula (4). Expression (5) is an expression indicating that the total N ₂ flow rate N2 _{all, blow} flowing from the tuyere is roughly balanced with the total N ₂ flow rate N2 _{all, top} discharged from the top of the furnace. Equation (6) is a modification of Equation (3). Equation (7) is the total top gas flow rate V _{all, top for} the total N ₂ dry flow rate N2 _{all, top, dry} discharged from _{the top.} And the nitrogen volume ratio x _{N2, top} at _{the top} of the furnace. By substituting Equation (6) and Equation (7) into Equation (5) and solving for the furnace top total gas flow rate V _{all, top} , Equation (8) is obtained. Since each term on the right side of Equation (8) is a known condition, the furnace top total gas flow rate V _{all, top} on a dry basis can be calculated from Equation (8). Here, when obtaining the furnace top total gas flow rate V _{all, top} , it is important to balance the nitrogen in the equation (5). Therefore, in addition to nitrogen normally blown with air from the tuyere, when nitrogen is enriched or blown from a place other than the tuyere, formula (2), formula (3), and Needless to say, it is necessary to appropriately correct the nitrogen flow rate for the equation (6) and the like.

The furnace top gas component is measured by gas chromatography, and the gas volume ratio of each component is estimated from the measurement result. Typically, the number of composition components measured on a dry basis is four, and carbon monoxide CO, carbon dioxide CO ₂ , nitrogen N ₂ , and hydrogen H ₂ are common. Equation (9) is obtained by the following equation: furnace top H ₂ gas volume ratio x _{H2, top, dry} , furnace top CO ₂ gas volume ratio x _{CO2, top, dry} , furnace top CO gas volume ratio x _{CO, top, dry} , furnace top N ₂ is a formula indicating that the sum of the volume ratios of the top gas components of the gas volume ratio x _{N2, top, dry} is 1.0. Here, all the furnace top gas component volume ratios on the left side of Expression (9) are known. And from the top gas flow rate V _{all, top} and the top gas component volume ratio, the gas molar flow rates of carbon monoxide CO and carbon dioxide CO _{2 at} the top of the furnace are expressed by the equations (10) and (11). Can be sought. Where ρ _{0, X} represents the density of component X in the standard state, and MW _X represents the molecular weight of component X. That is, since the amount of “carbon” gas discharged from the blast furnace is either carbon monoxide CO or carbon dioxide CO ₂ , it is expressed by equation (12) from equations (10) and (11). The In the equation (12), the “carbon” gas amount Carbon _{all, Gas} discharged from the blast furnace is converted to a unit of [kg / min] by multiplying by the carbon atomic amount MW _C.

The amount of carbon discharged from the top of the blast furnace occupies most of the amount of carbon consumed in the blast furnace, but the total amount of carbon used can be evaluated by including other contributions. For example, the total carbon usage amount Carbon _all is calculated using Equation (13). In the formula (13), in addition to the carbon discharged as the furnace top gas, the amount of carbon dissolved in the hot metal (mass% in hot metal: Mass% _C ) and the carbon in the dust discharged from the furnace top The amount Dust _{C is} also taken into consideration. Here, in Expression (13), the output amount P _max is generally expressed by [pig-ton / day], and unit adjustment for that is also performed. In addition, the definition of the amount of output P _max differs depending on the method of consideration such as the blast furnace downtime (breeze), but in order to compare the results of each furnace side by side, It may be desirable to use a soot amount P _max . The reason is that, for example, the amount of carbon discharged [kg] per day can be calculated by separately calculating the operating time of the blast furnace per day and multiplying it by equation (13). In addition, it is desirable that the calculation method of the amount P _max is a unified calculation method, but it is inevitable that there is a slight difference for each blast furnace. A typical method for calculating the amount P _max is the ore charging pitch from the furnace top (how many times ore was charged per unit time), the ore mass charged per charging pitch, ore It is calculated by multiplying the three items of the iron-containing mass ratio contained therein. The carbon amount Dust _C in the furnace top dust is considerably smaller than the “carbon” gas amount Carbon _{all, Gas} discharged in the blast furnace, but the amount of dust collected in the furnace top and It is possible to consider in terms of the average carbon content contained in the.

Finally, there is a method for calculating RAR based on the amount of carbon discharged as the furnace top gas (the amount of carbon used per pig iron production (the amount of output) P _max : hereinafter referred to as the RAR of the present invention). It calculates using Formula (14). For the equation (14), a conventional unit system conversion is also performed. In this case as well, it is desirable to use an output amount that does not include a resting time as the output amount _Pmax . Further, as described above, the normal RAR is also calculated based on the same concept. However, in the normal RAR, the carbon-containing raw material supply side (charging or charging) is used without using Carbon _{all, Gas} in Equation (14). The point calculated from the (blowing) condition is very different.

In the above calculation method, the measured value x _{X, top, dry} of the dry standard volume fraction is used as the furnace top gas component (component X). On the other hand, using the estimated value of the hydrogen utilization rate η _H2 , including the purpose of calculating the reduction amount by hydrogen, the measured value of the dry-based volume fraction is changed to the wet-based top gas various component volume fraction. A method of calculating the carbon amount Carbon _{all, Gas} discharged from the top of the furnace after conversion into the above is conceivable. However, also in this case, the calculation result of the equation (12) is exactly the same, and in principle, the calculation value of the carbon usage amount Carbon _{all, Gas} in the furnace top gas is the same regardless of which method is used. I also add that it has little effect.

  In FIG. 1, the schematic structure of the calculation apparatus of the carbon usage-amount in a blast furnace is shown. In FIG. 1, 101 is an input unit, and various operation data in the blast furnace are input as input conditions.

  Reference numeral 102 denotes a calculation unit, which executes time-series calculation processing using the mathematical formulas described so far.

  Reference numeral 103 denotes an output unit. For example, the total amount of carbon used in the blast furnace calculated by the calculation unit 102 (formula (13)), the RAR of the present invention (formula (14)), and the like are changed over time. Graph and output.

As input conditions of the input unit 101 in FIG. 1, the air flow rate V _{b at} the tuyere, the oxygen enrichment flow rate O2 at the tuyere, the furnace top CO gas volume ratio x _{CO, top, dry} , and the furnace top CO ₂ gas volume ratio x _{CO2, top, dry,} furnace top N ₂ gas volume ratio x _{N2, top, dry,} furnace top H ₂ gas volume ratio x _{H2, top, dry,} pig iron production (tapping quantity) P _max, in the hot metal For example, carbon mass% Mass% _C dissolved, carbon amount Dust _{C in} dust discharged from the top of the furnace, and the like. These data are input in time series. At that time, the processing may be performed using instantaneous value data. However, in consideration of the data accuracy, it is preferable to average the instantaneous value measurement data in advance and pass it to the calculation unit 102 in FIG. 1 as input data at intervals of 30 minutes or more. , Considered realistic.

  In the calculation unit 102 in FIG. 1, each calculation is executed from the input data using Expressions (1) to (14). Eventually, the calculation results of Expression (13) and Expression (14) become the output value of the amount of carbon used in the blast furnace of the present invention.

  Note that the carbon usage calculation device in the blast furnace of the present embodiment supplies a storage medium storing software program codes for realizing the functions described above to the system or apparatus, and the system (or CPU or CPU) of the system or apparatus. Needless to say, this can also be achieved by the MPU) reading and executing the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  In the calculation method of carbon usage in the blast furnace according to the present invention, the reliability of the estimated value of the total gas flow rate (formula (8)) discharged from the top of the furnace greatly affects its accuracy. That is, it is a big point to ensure sufficient measurement accuracy of the value of each term in Expression (8). Therefore, in order to use this index effectively, 1) an orifice-type flow meter that measures the flow rate of air from the tuyere, 2) a gas chromatography that measures the volume ratio of each gas at the top of the furnace, Needless to say, the measurement method should be standardized and standardized so as not to cause errors due to different measurement methods for each blast furnace.

It is also conceivable to perform a pure oxygen blowing operation of the air flow rate V _b = 0 in the equation (1) in the ultimate. In this case, since there is no inert gas component called nitrogen as described in the present invention, the inert gas (nitrogen) balance of the formula (5) cannot be considered, and the method of the present invention can be applied. It becomes impossible. In this case, it is necessary to consider so that an equation corresponding to the equation (5) is established by injecting an inert gas tracer such as nitrogen or argon from the tuyere. At that time, it goes without saying that it is necessary to blow in the tuyere and the top of the furnace so that the measurement accuracy of the inert gas component can be sufficiently obtained.

  In addition, the inert gas component referred to in the present invention refers to a gas component that is not directly involved in the iron ore reduction reaction of the blast furnace, and for example, nitrogen, argon, neon, xenon, and the like are conceivable. In the case of nitrogen, it is slightly contained in the feedstock, but it is assumed that the amount of nitrogen blown from the tuyere is overwhelmingly large. Therefore, when air / oxygen mixed gas close to pure oxygen is blown from the tuyere, whether or not nitrogen is appropriate as the inert gas needs to be examined in terms of the material balance of equation (5). In other words, when selecting the type of inert gas, it is necessary to carefully examine how much each inert gas is contained in the blast furnace feedstock, and there is no problem in the material balance corresponding to equation (5). It goes without saying that it is necessary to consider whether or not.

  In addition, so far, the description has been made assuming a general blast furnace operation on the assumption that most of the inert gas having nitrogen as a representative example is blown from the tuyere. However, for example, when introducing an inert gas in an amount that affects the material balance of equation (5) from a height position different from the tuyere, such as the shaft portion, the equation (5) Needless to say, it is necessary to derive an expression corresponding to 5).

  The carbon usage calculation method according to the present invention is a method for calculating the total carbon usage of the blast furnace alone or the RAR of the present invention alone. Therefore, even when carbon-containing gas such as carbon monoxide or carbon dioxide is blown in addition to oxygen / air normally blown from the tuyere, the nitrogen blowing ratio of the formula (3) should be corrected according to the blowing amount. For example, Expression (13) or Expression (14) can be applied. On the other hand, when a part of the furnace top gas is recycled and re-injected from the tuyere, there is also an idea of subtracting the amount of the carbon-containing gas recycled from the formula (13) or the formula (14). . However, in this case as well, if this gas recycling operation is considered to be an adjustment operation "outside the blast furnace system", the amount of carbon used in the blast furnace alone is evaluated by the equation (13) or the equation (14). It can be done.

FIG. 2 shows the estimated results of the input conditions (a) to (g) of the present invention, (h) the total carbon usage according to the present invention, and (i) the RAR of the present invention and the normal RAR for a certain blast furnace operation. The series (40 days) is shown. These are 24-hour average values, and the input data is the vertical axis value transition of the graph from the top to the seventh row. Note that (c) furnace top CO volume ratio, (d) furnace top CO ₂ volume ratio, (e) furnace top N ₂ volume ratio, etc. in FIG. In the calculation of (1), 1/100 is taken, and the calculation is performed in units according to the form of equation (9). The calculation results of the present invention (h) total carbon usage in FIG. 2 and (i) the RAR of the present invention are calculated by the equations (13) and (14), respectively. The amount of carbon Dust _C in the discharged dust is ignored. Here, each physical property value in the formulas (1) to (14) is assumed as follows. That is, the density [rho ₀ of CO gas in the standard _{state, CO} = _1.123kg / m ^_3, the density of CO ₂ gas in the standard state _{ρ 0, CO2 = 1.773kg / m} 3, the molecular weight of CO MW _CO = 28, CO ₂ molecular weight MW _CO2 = 44, carbon molecular weight MW _C = 12.

  It can be seen that (h) total carbon usage in FIG. 2 gradually increases during this period. Actually, during this period, as can be seen from the transition of the amount of output in Fig. 2 (f), the amount of output increased gradually, and as the amount of output increased, the total carbon usage increased. I understand that The vertical axis of the (h) total carbon usage graph of FIG. 2 is [kg / min] on average for 24 hours, and by multiplying this value by a value of 24 [hr] × 60 [min], The total amount of carbon used [kg] used per day can be calculated. However, it is needless to say that when the actual operation time is short due to a rest wind or the like, it is necessary to consider that amount.

In FIG. 2 (i) RAR and normal RAR of the present invention, in addition to the RAR of the present invention (left vertical axis: solid line), the normal RAR (right vertical axis: broken line) is also plotted. First, it can be seen that the absolute value of the RAR of the present invention is smaller than that of the normal RAR. This, in Formula (12), when converted to [kg / min] from [kg-mol / min], is due to the use of molecular weight MW _C carbon. That is, the present invention is characterized in that the molecular weight MW _C of carbon is used in order to calculate the substantial amount of carbon used. On the other hand, since RAR is usually calculated using “total carbon mass” such as coke and pulverized coal, in addition to carbon, the contribution of ash and moisture contained in them is added. This is the calculated value of. For reference, when the carbon reference molecular weight of coke and pulverized coal (converted from the number of ash moles attached to 1 mole of carbon) is estimated in a form containing ash, MW _{Coke & PC} = about 14-16. Therefore, in the formula (12), when the carbon reference molecular weight MW _{Coke & PC} of coke and pulverized coal is used in place of the molecular weight MW _C of carbon, the RAR of the present invention matches the order of the normal RAR. Specifically, when Equation (12) is rewritten based on this idea, Equation (15) is obtained.

  Thus, the RAR of the present invention is a calculated value obtained by quantifying the amount of “carbon” used, whereas the normal RAR is a calculated value including impurities other than carbon. Needless to say, the RAR of the present invention can appropriately evaluate the amount of “carbon” used even when the carbonaceous raw materials are compared between completely different conditions.

  In the graph of FIG. 2 (i), it can be said that the RARs of the two do not always change while maintaining the “parallel” relationship, as can be seen by comparing the movements of the RAR of the present invention and the normal RAR. Then, when evaluated by the RAR of the present invention, it can be seen that the “carbon” supply amount during this period hardly fluctuates with respect to the unit output, and stable “carbon” supply amount management can be performed. That is, in the RAR of the present invention, it is within a small fluctuation range within 10 kg / pig-ton. On the other hand, in normal RAR, there is a further fluctuation, and the fluctuation is not linked to the movement of the RAR of the present invention at all. As described above, since the amount of “carbon” is not clear only with the normal RAR, it is possible to make more accurate management of the “carbon” supply amount in actual operation by supplementing with the RAR of the present invention. .

FIG. 3 shows the results of comparing the correlation between the RAR of the present invention and the normal RAR for four blast furnaces having different furnace volumes. For each blast furnace, the two RARs calculated on average for 24 hours are further averaged for 30 days and plotted. The absolute values of the vertical axis (RAR of the present invention) and the horizontal axis (normal RAR) are deviated for the reasons already described. FIG. 3 also shows two lines, a solid line and a broken line. These lines are based on the equation (12) and the equation (15). It is displayed in a straight line assuming that the relationship shown in FIG. Expression (16) is an approximate expression that is generally established when the influence of carbon mass% Mass% _C dissolved in the hot metal and the carbon amount Dust _{C in} the dust discharged from the furnace top is negligible. It is.

As shown in the legend of FIG. 3, when the solid line is the carbon reference molecular weight MW _{Coke & PC} = 15 of coke and pulverized coal, the broken line is the carbon reference molecular weight MW _{Coke & PC} = 16 of coke and pulverized coal. Each straight line. Considering that the carbon reference molecular weight MW _{Coke & PC of} standard coke is about 15, it can be expected that the relationship between the RAR of the present invention and the normal RAR is plotted around these two straight lines.

  About the blast furnace 1 and the blast furnace 2, it operate | moves between both straight lines, and it can be guessed that the carbon material raw material condition change widths, such as coke and pulverized coal, are comparatively small. On the other hand, regarding the blast furnace 3, particularly in the region indicated by "A", although the RAR is usually low, it is shown that the RAR according to the present invention performed a relatively high operation. To explain this phenomenon qualitatively, the blast furnace 3 in the period “A” is operated using a raw material having a low ash content and a relatively high carbon content as a raw material condition of the used carbonaceous material. It can be interpreted that there was a high possibility that On the other hand, for the blast furnace 4, in the region indicated by "B", the RAR according to the present invention was operated at a relatively low operation while the operation was normally performed at a high RAR. If the same explanation is added, the blast furnace 4 in the period of the region “B” is interpreted as having a high possibility of being operated using an inferior raw material having a high ash content ratio and a low carbon content ratio. can do.

  As described above, since the normal RAR is originally calculated based on the simple mass of the carbonaceous material, in principle, “carbon” and “impurities” contained in the carbonaceous material cannot be distinguished. In other words, the normal RAR is not an index that appropriately reflects the actual amount of carbon used. Therefore, by using the RAR of the present invention, the relationship as shown in FIG. 3 can be clearly shown, and the actual amount of “carbon” can be grasped. For example, in daily operation management, when it is in the area “B” of the blast furnace 4 in FIG. If you take action to make up for the carbon deficiency, you can avoid major operational problems.

  As described above, even when managing the blast furnace operation centering on the normal RAR, the relationship as shown in FIG. 3 is obtained from the RAR of the present invention, and the validity of the normal RAR calculation value is evaluated to ensure the accuracy. It is considered to be very meaningful to be linked to the judgment of a proper operation action. As already explained, the plot position of the correlation between the two RARs shown in FIG. 3 depends on the amount of impurities contained in the used carbonaceous material. Therefore, when there is an operational state at the positions “A” and “B” in FIG. 3, the coke and pulverized coal used are analyzed in terms of industrial analysis values, ash mass ratio, ash. If the validity of the normal RAR calculation value can be evaluated after checking the result of impurity analysis such as the component analysis value, it is considered that a more desirable blast furnace operation action can be determined.

101 Input unit 102 Calculation unit 103 Output unit

Claims (5)

  From the total flow rate of the inert gas blown into the blast furnace furnace and the analysis value of the inert gas volume fraction of the furnace top exhaust gas, the total flow rate of the furnace top exhaust gas is obtained, and the carbon dioxide volume fraction of the furnace top exhaust gas is obtained. A blast furnace characterized by calculating a carbon emission amount from the furnace top exhaust gas from a rate and a carbon monoxide volume fraction, and calculating a total carbon usage amount or a reducing material ratio (RAR) used in the blast furnace Of calculating carbon usage in Japan.   The method for calculating the amount of carbon used in a blast furnace according to claim 1, wherein nitrogen is used as the inert gas. By comparing the RAR calculated by the carbon usage calculation method in the blast furnace according to claim 1 or 2 with the normal RAR calculated from the amount of carbon supplied to the blast furnace, the validity of the normal RAR can be confirmed. A method for evaluating the validity of a normal RAR, characterized by evaluating .   From the total flow rate of the inert gas blown into the blast furnace furnace and the analysis value of the inert gas volume fraction of the furnace top exhaust gas, the total flow rate of the furnace top exhaust gas is obtained, and the carbon dioxide volume fraction of the furnace top exhaust gas is obtained. And calculating means for calculating the carbon emission amount from the top exhaust gas from the carbon monoxide volume fraction and the carbon monoxide volume fraction, and calculating the total carbon usage amount or reducing material ratio (RAR) used in the blast furnace. An apparatus for calculating the amount of carbon used in a blast furnace.   From the total flow rate of the inert gas blown into the blast furnace furnace and the analysis value of the inert gas volume fraction of the furnace top exhaust gas, the total flow rate of the furnace top exhaust gas is obtained, and the carbon dioxide volume fraction of the furnace top exhaust gas is obtained. The amount of carbon discharged from the furnace top exhaust gas is calculated from the rate and the volume fraction of carbon monoxide, and the computer is caused to execute processing for calculating the total amount of carbon used in the blast furnace or the reducing material ratio (RAR). Program for.

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