JP5682576B2 - Exhaust gas recovery method for converter - Google Patents

Description

  The present invention relates to a converter exhaust gas recovery method for recovering exhaust gas rich in CO gas generated during blowing of a converter.

  In the converter, oxygen is blown into the furnace, and auxiliary materials such as quick lime are added to oxidize and remove carbon, silicon, phosphorus and the like contained in the molten steel. At that time, a large amount of exhaust gas rich in CO component is generated along with the decarburization reaction. As shown in FIG. 1, this exhaust gas is drawn into the hood through the skirt, cooled and dust-removed, and then the exhaust gas having a high CO concentration is recovered as a valuable gas by the switching valve, and the CO concentration is low. The exhaust gas is burned at the top through the chimney and released into the atmosphere. The general flow of exhaust gas recovery in the converter is shown below.

<STEP1>
When oxygen blowing into the furnace is started, the decarburization reaction proceeds and the CO concentration in the exhaust gas increases. When the CO gas concentration in the exhaust gas continuously measured by the exhaust gas component analyzer exceeds a set value, gas recovery to the gas holder is started.

<STEP2>
After the start of exhaust gas recovery, in order to increase the recovery efficiency of CO gas, the furnace pressure is detected by a pressure detector installed at the furnace port, and the internal pressure of the furnace becomes equal to the external pressure mainly by feedback control. The furnace pressure is controlled using the damper opening as the operation amount. This is because if the furnace pressure is higher than the external pressure, the exhaust gas flows out of the furnace through the gap between the furnace port and the skirt, resulting in CO gas loss. Conversely, if the furnace pressure is lower than the external pressure, This is because the CO gas flows into the furnace and the CO gas in the furnace reacts with oxygen in the outside air to burn the CO gas, which is also a loss of the CO gas.

<STEP3>
When the decarburization reaction accompanying oxygen blowing proceeds and the carbon concentration in the molten steel decreases, the CO concentration in the exhaust gas also decreases. Therefore, when the CO concentration measured by the exhaust gas component analyzer falls below a certain set value, exhaust gas recovery is terminated. The exhaust gas after completion of recovery is diffused through the chimney.

  In the prior art, the CO concentration measured by the exhaust gas component analyzer was used as the judgment standard for the start and end of exhaust gas recovery in STEP 1 and STEP 3. However, since concentration time measurement with an exhaust gas component analyzer requires an analysis time of several tens of seconds, the CO concentration output at this time is past data. Therefore, if the start / end of exhaust gas recovery is judged based on the measured CO concentration by the exhaust gas component analyzer, as shown in FIG. The problem of calorie reduction due to gas recovery.

  Many techniques related to furnace pressure control shown in STEP 2 have been disclosed so far. For example, Patent Document 1 discloses that a furnace internal pressure target value is set to a predetermined amount in order to suppress a rapid fluctuation in the internal pressure of the furnace with respect to a sudden change in the amount of exhaust gas generated when the auxiliary raw material is charged or when the amount of injected oxygen is changed. A control method for changing only the time is disclosed. In Patent Document 2, the deviation between the estimated value and the actual value of the amount of exhaust gas generated in the furnace at the time of prediction is obtained, the estimated value of the amount of generated exhaust gas at the time of prediction is corrected with the deviation, and the internal pressure of the furnace is obtained. A control device is disclosed in which a parameter is corrected based on a ratio of a tracked air amount and a target air amount that change from moment to moment and set as a furnace pressure target value.

Japanese Patent Publication No. 6-74449 Japanese Examined Patent Publication No. 62-17003

  With the technique disclosed in Patent Document 1 and the technique disclosed in Patent Document 2, a rapid furnace pressure fluctuation is suppressed as much as possible to improve gas recovery efficiency. However, there is no description regarding slopping in which the most rapid fluctuation in the furnace pressure occurs. Since control of the furnace pressure becomes difficult when slopping occurs, even if the techniques of both documents that do not consider slopping are applied, there will be a problem of deterioration in the quality of the gas accumulated in the gas holder when slopping occurs. It is expected to be.

  Then, this invention makes it a subject to provide the exhaust gas recovery method of a converter which can suppress the recovery loss of exhaust gas, and the quality fall of the gas accumulate | stored in a gas holder.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiments.

The present invention is a converter of a converter in which a hood and a skirt are attached to the tip of an exhaust gas duct, arranged on the converter furnace port, and exhaust gas generated from the converter during blowing is sucked through the exhaust gas duct to recover the exhaust gas. In the converter exhaust gas recovery method using the exhaust gas recovery device (10), the converter exhaust gas recovery device (10) uses the main raw material information as an initial value, the sub raw material input information and the top bottom blowing gas flow rate information every moment. The in-furnace gas flow calculation unit (4) for obtaining the in-furnace generated gas flow rate from the furnace and the skirt height, damper opening, induction pressure, in-furnace generated gas flow rate calculation unit (4) Furnace pressure calculation unit that calculates the furnace pressure from the flow rate of the generated gas and the inflow resistance between the skirt and the furnace port expressed using the height of the skirt and the inflow resistance of the damper expressed using the damper opening ( 5) and the furnace pressure An intrusion air amount calculation unit (6) for determining the amount of air entering from the gap between the skirt and the converter furnace port from the furnace pressure calculated in the calculation unit (5) and the inflow resistance between the skirt and the furnace port; Exhaust gas component and flow rate for obtaining exhaust gas component and exhaust gas flow rate in exhaust gas duct from furnace generated gas flow rate calculated by internally generated gas flow rate calculation unit (4) and intrusion air amount calculated by intrusion air amount calculation unit (6) An exhaust gas recovery device (10) for the converter when the CO concentration of the exhaust gas calculated by the exhaust gas component / flow rate calculation unit (7) is not less than an arbitrary set value. An exhaust gas recovery method for a converter, characterized in that exhaust gas recovery is performed.

  In the present invention, it is preferable to determine the inflow resistance between the skirt and the furnace port by using a linear form of the skirt height.

  Moreover, in the said invention, it is preferable to obtain | require the inflow resistance of a damper using the power equation of a damper opening degree.

In the above present invention, the exhaust gas component analysis value, the exhaust gas flow rate measured value, an upper bottom blown gas flow rate, the oxygen balance from the furnace accumulated oxygen per unit O _S obtaining by calculation from the sub-raw material input and the hot metal components, the minus exhaust gas components and gas flow rate calculated in exhaust gas components, flow rate calculation unit, an upper bottom blown gas flow rate, a secondary raw material input and furnace accumulated oxygen per unit obtained by calculating the oxygen balance from the hot metal components O _{S '} It is preferable to perform exhaust gas recovery when the value O _S −O _S ′ is equal to or less than an arbitrary set value.

  According to the present invention, it becomes possible to estimate the components and flow rate of exhaust gas generated during blowing of a converter (hereinafter sometimes referred to as “exhaust gas component / flow rate”) with high accuracy, and the analysis of the exhaust gas component analyzer. It is not affected by the time delay, and a larger amount of exhaust gas having a high CO concentration can be recovered. Accordingly, it is possible to provide a converter exhaust gas recovery method capable of suppressing the exhaust gas recovery loss and the deterioration of the quality of the gas accumulated in the gas holder even when slopping occurs.

It is a schematic diagram of a converter exhaust gas recovery equipment. It is a conceptual diagram of transition of exhaust gas CO concentration. It is a conceptual diagram of an OG model. It is a figure explaining reaction considered with a reaction model in a converter furnace. It is a figure explaining the view of an integrated model. It is a figure which shows transition of the estimated value and actual value of a furnace internal pressure, exhaust gas component, and flow volume. It is a figure explaining the exhaust gas recovery apparatus 10 of a converter. Is a diagram illustrating an example of progression of delta O.D. _S. It is a figure explaining the exhaust gas recovery method of the converter of the present invention.

  Embodiments of the present invention will be described below.

If the estimated value of CO concentration in exhaust gas by a mathematical model can be used as the CO concentration in exhaust gas, which is the criterion for determining the start and end of exhaust gas recovery, instead of the measured value by the exhaust gas component analyzer, the above-mentioned problem of analysis delay can be solved. Solvable. In Patent Document 2, it is proposed to calculate the generated gas flow rate in the converter furnace by a mathematical model, but the exhaust gas from the converter through the duct to the gas holder is not the object of modeling. .
Therefore, as a result of repeated studies, the inventors have dynamically calculated the molten steel / slag component temperature in the furnace and estimated the flow rate of the gas generated in the furnace, the furnace pressure of the furnace mouth, the furnace mouth and the skirt. We focused on a method for estimating the components and flow rate of exhaust gas in combination with a mathematical model that estimates the amount of air intruding from between.

Further, when CO gas or CO ₂ gas generated in the furnace is trapped in the slag, a foaming state is formed, and when the forming grows, slag overflows out of the furnace. If forming that can lead to slopping can be detected, exhaust gas recovery can be interrupted and quality degradation of the exhaust gas accumulated in the gas holder can be avoided, but precise modeling of the formation and growth mechanism of the forming is very difficult.
Therefore, as a result of repeated studies, the present inventors have utilized the in-furnace oxygen storage basic unit (a calculation method will be described later) obtained using the above-described estimated values of exhaust gas components and flow rates to form a state. We focused on the method of estimating.

  First, a method for estimating the furnace pressure and the intrusion air amount will be described. As shown in FIG. 3, the converter and exhaust gas recovery facility shown in FIG. 1 are divided into four blocks: (i) converter, (ii) skirt, (iii) flue, and (iv) IDF. Think about it. The definition of pressure in the figure is shown in Table 1, and the definition of gas flow rate is shown in Table 2.

  First, the relationship between pressure and gas flow rate is defined by the following formula (1). The gas flow rate is proportional to the square root of the pressure difference between the blocks, and is based on Bernoulli's theorem. K is a parameter representing resistance.

  Next, based on the above concept, the exhaust gas flow rate and the amount of intrusion air from the furnace port are expressed by the following formula (2) and the following formula (3), respectively.

_{Here, F IDF} is (ii) a skirt portion and (iv) gas flow rate between blocks of IDF (= exhaust gas flow rate), _{F a} gas flow rate between blocks of the atmosphere and (ii) a skirt portion (= intrusion air Amount). Furthermore, inflow resistance K _D of the damper is a function of the damper opening h _D (power equation), inflow resistance K _S between the skirt furnace port is a function of the skirt height h _S (linear equation). _The K _{D h D,} alpha _D, and, using a beta _D is represented in the form of the following formula (4), _{K S} is _{h S,} alpha _S, and, by using a beta _S form of the following formula (5) It is represented by

  Further, it is assumed that the following equation (6) is established regarding the gas flow rate on the premise that the response of the pressure and the gas flow rate is sufficiently fast.

In the formula (6), 0.79 multiplied by the intrusion air quantity F _a represents an oxygen loss due to secondary combustion with entering air oxygen.

From the above, atmospheric pressure (P _a = 0 [Pa]), IDF intake pressure (P _IDF [Pa]), converter generated gas flow rate (F _CV [Nm ³ / h]), damper opening (h _D ) When the skirt height (h _S ) is given, the following equation (7) is obtained by applying the equations (2) and (3) to the equation (6). The following equation (7) becomes a nonlinear equation having only the furnace pressure (P ₀ ) as a variable, and the furnace pressure (P ₀ ) can be calculated by solving this equation. Further, the exhaust gas flow rate (F _IDF ) and the intrusion air amount (F _a ) can be obtained from the equations (2) and (3) using the calculated furnace pressure (P ₀ ).

Further, according to the following formulas (8) to (10), the CO gas flow rate, the CO ₂ gas flow rate in the exhaust gas, and the N ₂ gas flow rate (F _{IDF, CO} [Nm ³ / h], F _{IDF, CO 2} [Nm] ³ / h], F _{IDF, N2} [Nm ³ / h]), and finally, the exhaust gas component concentration estimated values (C _CO [%], C _CO2 can be calculated from the following formulas (11) to (13). [%], C _N2 [%]). Hereinafter, a series of mathematical models for obtaining the furnace pressure, the intrusion air amount, and the exhaust gas component / flow rate are referred to as “OG model”. F _{CV, CO} is the in-furnace generated CO gas flow rate [Nm ³ / h], and F _CV, CO ₂ is the in-furnace generated CO ₂ gas flow rate [Nm ³ / h].

Next, a method for estimating the furnace generated gas flow rate (F _CV ) will be described.
The in-furnace generated gas flow rate F _CV is the sum of the in-furnace generated CO gas flow rate generated by the decarburization reaction in the furnace and the in-furnace generated CO ₂ gas flow rate generated by the secondary combustion of the in-furnace generated CO gas. Defined. The flow rate of CO gas generated in the furnace can be obtained from a converter reaction model, and many converter reaction models have been proposed so far. Here, a model proposed by the whip that calculates the changes in the molten steel composition and temperature during blowing from the mass balance equation and the heat balance equation (Whizuru, Akira Moriyama, “Metallurgy Reaction Engineering”, Yokendo, 1972).

  As the converter blowing reaction, six types of reactions as shown in FIG. 4 (fire point reaction, CO gas oxidation reaction, slag generation reaction, slag-metal reaction, scrap and cold metal melting, and secondary reaction Consider material decomposition. FIG. 4 shows “Ryoichi Takahashi,“ Control in the Steel Industry ”, Corona, 2002, p. 39 ”.

In the hot spot reaction, each component in the molten steel is oxidized by the supplied oxygen. At this time, the O ₂ distribution ratio to each component oxidation is considered to be proportional to the product of the concentration of each component and the reaction rate constant. That is,

Here, σ _i is the O ₂ distribution ratio to i-component oxidation, κ _i is the reaction rate constant [kg / (kmol · s)] of i-component oxidation, and C _im is the i-component concentration in the metal [kmol / kg]. It is.

  And the change of each component in the molten steel in the blowing process moves from the scrap or cold metal to the molten steel with the amount of change in the hot spot reaction, the amount of change due to the reaction between slag metals, and the melting of the scrap and cold metal. It is expressed as the sum of the amount to do. The balance equation of carbon in molten steel is represented by the following formula (15).

Here, _{W m} is the molten steel weight _{[kg], W CM} is Hiyazuku weight _{[kg], W SC} scrap weight _{[kg], C iCM} the i component concentration in Hiyazuku [kmol / _{kg], C iSC} is The i component concentration in the scrap [kmol / kg], V _O2 is the oxygen supply rate [kmol / s].

The in-furnace generated CO gas flow rate and the in-furnace generated CO ₂ gas flow rate are expressed by the following formula (16) and the following formula (17) from the formula (15). The following equation (18) is an equation representing the secondary combustion rate, and is defined as a function such as the upper blown oxygen flow rate or the lance hot water surface distance.

Here, CO _V is the amount of CO gas generated in the furnace [Nm ³ ], CO 2 _V is the amount of CO ₂ gas generated in the furnace [Nm ³ ], α _CO2 is the secondary combustion rate, and FO ₂ is the upper blowing acid rate [Nm 3 ³ / s], L _ν is the distance between lances [m].

  In addition to the heat of reaction, heat of fusion, and heat of decomposition shown in FIG. 4, each amount of heat, such as heat dissipated from the iron skin and furnace opening and heat transfer between slag metals, is distributed to the molten steel at a certain ratio. The heat balance equation is expressed as the following equation (19).

Here, _{c P} is the molten steel specific heat [kcal / (kg · ℃) ], T m is the molten steel temperature [° C.], _{Q 1} fire point reaction heat, _{Q 2} is slag generated heat, _{Q 3} slag metal reaction heat, Q ₄ are furnace secondary combustion heat, Q ₅ is a scrap melting heat, Q ₆ is an auxiliary raw material decomposition heat.

Then, the main raw material information is used as an initial value, and the gas generated in the furnace is solved by solving the simultaneous differential equations consisting of the material balance equation and the heat balance equation based on the information on the input of the auxiliary raw material and the information on the top bottom blowing gas flow. A flow rate (= in-furnace generated CO gas flow rate (CO _V ) + in-furnace generated CO ₂ gas flow rate (CO _{2 V} )) is obtained.

  By combining the reactor internal reaction model and the OG model, it is possible to estimate and calculate exhaust gas components and flow rates from moment to moment (hereinafter, a model combining the reactor internal reaction model and the OG model is referred to as “ In other words, as shown in FIG. 5, the in-furnace gas flow calculated in the converter reaction model is used as input information to the OG model, so that the results of the in-furnace reaction can be obtained. In addition, it is possible to dynamically estimate exhaust gas components and flow rates that reflect actual exhaust gas recovery equipment information (skirt height, damper opening, and attractive pressure). FIG. 6 shows estimated values and actual values of furnace pressure and exhaust gas components / flow rates. As shown in FIG. 6, all can be estimated well.

  And exhaust gas can be collect | recovered without using an exhaust gas component analyzer by judging exhaust gas collection | recovery start / end using the estimated value of CO concentration in exhaust gas which illustrated the estimated value and the actual value in FIG. That is, by adopting such a configuration, it is possible to truly recover exhaust gas without being affected by the analysis delay time by the exhaust gas component analyzer.

  Next, a description will be given of a method for detecting forming that leads to slapping by using the estimated values of the exhaust gas component and the exhaust gas flow rate by the integrated model.

First, exhaust gas components measured by the exhaust gas components analyzer, and, based on the exhaust gas flow rate value measured by the venturi flow meter, the method of calculating the furnace accumulated oxygen per unit O _S. Furnace accumulated oxygen per unit O _S is calculated based on the oxygen balance in the furnace, generally, there is a corresponding FeO of the generated slag.

CO flow rate V _CO [Nm ³ / h] in exhaust gas, CO ₂ flow rate V _CO2 [Nm ³ / h] in exhaust gas, O ₂ flow rate V _O2 [Nm ³ / h] in exhaust gas, N ₂ flow rate in exhaust gas V _N2 [Nm ³ / h], in-furnace generated CO flow rate V _CO ^V [Nm ³ / h], and in-furnace generated CO ₂ flow rate V _CO2 ^V [Nm ³ / h] are respectively the following formulas (20): Thru | or Formula (25).

Here, h _CO and h _CO2 are exhaust gas component measured values [%], Q _offgas is an exhaust gas flow rate measured value [Nm ³ / h], and i_delay is an exhaust gas analysis delay [−].

Further, the in-furnace accumulated oxygen change amount dO _S [Nm ³ / s] and the in-furnace accumulated oxygen amount basic unit O _S [Nm ³ / ton] are expressed by the following formulas (26) and (27).

Here, (% SiO ₂ ) consumed oxygen is the amount of oxygen [m ³ ] consumed by SiO ₂ formation in the hot metal de-Si period, and W _st is the molten steel weight [ton].

Assuming that forming has occurred, the internally generated CO gas that flows out of the furnace and the CO ₂ gas generated in the furnace are trapped in the slag. Therefore, the oxygen stored in the furnace based on the above calculation method. per unit O _S is apparently increased. However, even if the increase in furnace accumulated oxygen per unit O _S was observed, determination of whether it is a thing due to the decrease in such the either the decarburization reaction efficiency due to the forming is difficult.

On the other hand, since the integrated model is based on the assumption that the slag is in a normal state, the exhaust gas component / flow rate at which the CO gas generated in the furnace or the CO ₂ gas generated in the furnace is not trapped by the slag is estimated. Then, compared with these estimates furnace residual oxygen per unit O _S calculated based on _'the above furnace accumulated oxygen per unit O _S, can be determined whether there are any forming state.

That is, the formula (28), exhaust gas components measured by the exhaust gas components analyzer, and, the furnace accumulates oxygen per unit O _S based on exhaust gas flow rate value measured by the venturi flow meter, estimated in integration model determining the difference between the exhaust gas components and gas flow furnace accumulation was determined on the basis of oxygen per unit O _{S 'is,} when it becomes more than a certain set value is in the forming state at risk of leading to slopping can do. Therefore, if the exhaust gas is recovered when ΔO _S is equal to or less than a certain set value, it is possible to avoid a reduction in the quality of the exhaust gas accumulated in the gas holder.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 7, the structural example of the exhaust gas recovery apparatus 10 of the converter which can apply the exhaust gas recovery method of the converter of this invention is shown.
Hot metal data 1 is data of hot metal conditions such as hot metal weight for each charge, hot metal components (C, Si, Mn, P, etc.), hot metal temperature, and hot metal ratio. The target data 2 is data of target components (C, Si, Mn, P, etc.) and target temperature for each charge. In parameter 3, parameters such as a coefficient of a power expression of the damper opening (formula (4)) and a linear form of the skirt height (formula (5)), exhaust gas recovery reference CO concentration, forming determination reference value, and the like are set.

  The in-furnace generated gas flow rate calculation unit 4 calculates an estimated value of the in-furnace generated gas flow rate together with the molten steel components and temperature based on the converter furnace reaction model.

  In the furnace pressure calculation unit 5, exhaust gas recovery equipment data such as skirt height, damper opening, and attraction pressure, the inflow resistance between the skirt and the furnace opening, the inflow resistance of the damper, and the generated gas in the furnace Based on the estimated value of the generated gas flow rate in the furnace calculated by the flow rate calculation unit 4, the estimated value of the in-furnace pressure is calculated from the equation (7).

  Based on the estimated value of the furnace pressure calculated by the furnace pressure calculation unit 5 and the inflow resistance between the skirt and the furnace port, the intrusion air amount calculation unit 6 calculates from the gap between the skirt and the furnace port. Calculate the estimated amount of air that enters.

  In the exhaust gas component / flow rate calculation unit 7, the estimated value of the in-furnace generated gas flow calculated by the in-furnace generated gas flow rate calculation unit 4, the estimated value of the in-furnace pressure calculated by the in-furnace pressure calculation unit 5, and the intrusion air amount calculation unit Based on the estimated value of the intrusion air amount calculated in step 6, the estimated value of the exhaust gas component / flow rate is calculated. Then, when the estimated value of the calculated exhaust gas CO concentration is a certain set value (for example, 40% to 60%) or more, the recovery valve 11 is operated so as to recover the exhaust gas. For example, when the previous set value is a small value (about 20%), there is a problem that the calorie of the gas accumulated in the gas holder decreases, and conversely, if the set value is too large (about 80%), the gas holder Although the calories themselves of the gas accumulated in the gas rise, the CO gas lost due to diffusion increases. In general converter operation, it is generally set to 40% to 60%.

In the in-furnace oxygen storage unit calculation unit 8, the hot metal data 1, the top bottom blown oxygen flow rate, the amount of auxiliary raw material input, and the exhaust gas information (exhaust gas flow rate measured by the exhaust gas flow meter 12 and exhaust gas component analyzer 13 calculates the furnace residual oxygen per unit O _S based on the analytical values of the exhaust gas components), furnace residual oxygen quantity based on the exhaust gas information by integrating the model (estimated value of the estimated value and exhaust gas components of the exhaust gas flow rate) The basic unit O _S 'is calculated. When ΔO _S (= O _S −O _S ′) is equal to or less than a certain set value (for example, 4.0 [Nm ³ / ton]), the recovery valve 11 is operated so as to recover the exhaust gas.
Here, FIG. 8 shows a transition example of ΔO _S when large-scale slapping occurs. The vertical axis in FIG. 8 is ΔO _S [Nm ³ / ton], and the horizontal axis is the blowing time [s]. As shown in FIG. 8, when large-scale slopping has occurred, it can be seen that ΔO _S is greatly increased compared to ordinary blowing. If, for example, about 4.0 [Nm ³ / ton] is set as the previous set value, it is possible to stop the gas recovery at the time of the occurrence of the slopping, and the deterioration of the quality of the gas accumulated in the gas holder can be suppressed. .

  The input / output unit 9 has an interface function such as displaying an estimated value of exhaust gas components and a basic unit of oxygen amount accumulated in the furnace, and correction input of target data 2 and parameter 3.

  Next, details of processing performed by the exhaust gas component / flow rate calculation unit 7 and the in-furnace oxygen storage unit calculation unit 8 will be described using the flowchart shown in FIG.

  In S1, data such as hot metal weight is collected from hot metal data 1. In S2, the top bottom blowing gas flow rate and the amount of auxiliary raw material input during blowing are collected sequentially, and the in-furnace generated gas flow rate is obtained by a converter furnace reaction model.

In S3, the estimated value of the in-furnace gas flow obtained in S2 and the exhaust gas recovery device data such as the damper opening, the skirt height, and the induction pressure are collected to obtain the estimated value of the in-furnace pressure. In S4, the intrusion air amount is obtained according to the equation (3) using the estimated value of the furnace pressure obtained in S3. In S5, the exhaust gas component / flow rate is estimated using the intrusion air amount obtained in S4. In S6, the residual oxygen intensity O _S ′ in the furnace based on the exhaust gas component / flow rate obtained in S5 and the exhaust gas information (the measured value of the exhaust gas flow rate by the exhaust gas flow meter 12 and the analyzed value of the exhaust gas component by the exhaust gas component analyzer 13). ) furnace residual oxygen per unit O _S based on finding. Thereafter, in S7, it is determined whether or not blowing is in progress. If blowing, the process returns to S2 and the same process is repeated.

And when exhaust gas CO density | concentration estimated value calculated | required by the said flow becomes more than a preset value, exhaust gas with a high CO density | concentration can be collect | recovered more by performing exhaust gas recovery. Further, if the exhaust gas is recovered when ΔO _S (= O _S −O _S ′) obtained by the above flow is equal to or smaller than a certain set value, the gas accumulated in the gas holder can be obtained even if slapping occurs. The exhaust gas can be recovered without degrading the quality. By following the above procedure, it becomes possible to accurately estimate the components and flow rate of the exhaust gas generated during the blowing of the converter, without being affected by the analysis time delay of the exhaust gas component analyzer, and the CO concentration A large amount of high exhaust gas can be recovered.

DESCRIPTION OF SYMBOLS 1 ... Hot metal data 2 ... Target data 3 ... Parameter 4 ... Furnace generation gas flow rate calculation part 5 ... Furnace pressure calculation part 6 ... Intrusion air amount calculation part 7 ... Exhaust gas component and flow rate calculation part 8 ... In-furnace oxygen storage basic unit Arithmetic unit 9: Input / output unit 10 ... Converter exhaust gas recovery device 11 ... Recovery valve 12 ... Exhaust gas flow meter 13 ... Exhaust gas component analyzer

Claims (4)

Exhaust gas recovery of a converter that attaches a hood and a skirt to the tip of the exhaust gas duct, arranges it on the converter furnace mouth, sucks exhaust gas generated from the converter during blowing, and collects the exhaust gas through the exhaust gas duct In an exhaust gas recovery method for a converter using an apparatus,
The converter exhaust gas recovery device,
The main raw material information is set as an initial value, and the in-furnace generated gas flow rate calculation unit for obtaining the in-furnace generated gas flow rate from the momentary sub raw material input information and the top bottom blowing gas flow rate information,
Said skirt height every moment, the damper opening, attractants pressure, the furnace generating the gas flow furnace generating the gas flow rate calculated by the calculation unit, and the skirt-furnace port which is represented with the height of said skirt A furnace pressure calculation unit for obtaining a furnace pressure from an inflow resistance between the damper and an inflow resistance of the damper represented by using the damper opening;
An intrusion air amount calculation unit for obtaining the amount of air entering from the gap between the skirt and the converter furnace port from the furnace pressure calculated by the furnace pressure calculation unit and the inflow resistance between the skirt and the furnace port;
An exhaust gas component / flow rate calculation unit for obtaining an exhaust gas component in the exhaust gas duct and an exhaust gas flow rate from the in-furnace generated gas flow rate calculated by the in-furnace generated gas flow rate calculation unit and the intrusion air amount calculated by the intrusion air amount calculation unit And having
When the CO concentration of the exhaust gas calculated by the exhaust gas component / flow rate calculation unit is not less than an arbitrary set value, exhaust gas recovery is performed using the exhaust gas recovery device of the converter. Exhaust gas recovery method.   The exhaust gas recovery method for a converter according to claim 1, wherein an inflow resistance between the skirt and the furnace port is obtained using a linear form of the height of the skirt.   The exhaust gas recovery method for a converter according to claim 1 or 2, wherein an inflow resistance of the damper is obtained by using a power expression of the damper opening degree. Exhaust gas component analysis value, the exhaust gas flow rate measured value, an upper bottom blown gas flow rate, the oxygen balance from the furnace accumulated oxygen per unit O _S obtaining by calculation from the sub-raw material input and the hot metal components in the exhaust gas components, flow rate calculation unit A value O _S obtained by subtracting the oxygen storage basic unit O _S ′ obtained by calculating the oxygen balance from the calculated exhaust gas component and the exhaust gas flow rate, the top bottom blowing gas flow rate, the auxiliary raw material input amount, and the hot metal component. The exhaust gas recovery method for a converter according to any one of claims 1 to 3, wherein exhaust gas recovery is performed when -O _S 'is not more than an arbitrary set value.