KR100910453B1 - A detecting and controlling method for supplying the fine coal into furnace - Google Patents

Abstract

The present invention calculates the current blowing amount through the statistical regression equation using the detected powdered coal weight value and the weight detection time in the pulverized coal feed tank of the blast furnace coal injection facility, and compares the calculated current blowing amount with the target blowing amount. The present invention relates to a blast furnace pulverized coal injection amount detection and control method for controlling the injection amount using the results.

To this end, the present invention, the blast furnace pulverized coal injection having a feed tank for pulverizing pulverized coal to the blast furnace, a charge valve and vent valve for controlling the pressurization and back pressure of the pressure in the feed tank, respectively, and a load cell for detecting the pulverized coal weight in the feed tank A method for detecting and controlling blast furnace pulverized coal in a facility, the method comprising: a weight value input step of receiving a pulverized coal weight value detected in the load cell; A sampling time setting step of setting a time (T) for sampling the input pulverized coal weight value; A sampling number setting step of setting a number of sampling the input pulverized coal weight value (M) according to the set sampling time; A weight value sampling step of sampling the input pulverized coal weight value M according to the set sampling time and the number of samplings; A blowing amount calculating step of calculating a current fine coal injection amount (b) in the feed tank using the sampling time (T) and the sampled weight value (M); And a valve adjusting step of adjusting the filling valve and the vent valve such that the calculated current pulverized coal injection amount b and the predetermined target injection amount B are equal to each other.

According to the present invention, not only the reduction rate of blowing amount but also the detection time can be reduced by more than 5 times compared to the existing detection method, so that it is possible to control the stable blowing amount and finally to achieve uniform coal injection into the blast furnace to prevent thermal fluctuations in the blast furnace. And through improved breathability has a great effect on improving the quality and productivity of the molten iron.

Blast Furnace, Pulverized Coal, Weight, Blowing Amount, Feed Tank, Pressure Reducing Valve, Vent Valve, Sampling

Description

A DETECTING AND CONTROLLING METHOD FOR SUPPLYING THE FINE COAL INTO FURNACE}

1 is a configuration diagram of a general blast furnace pulverized coal injection facility.

2 is a process chart showing a conventional blast furnace pulverized coal blowing principle.

3 is a flow chart showing a conventional blast furnace pulverized coal injection amount detection and control process.

4 is a graph of the blowing amount according to the conventional blast furnace fine coal injection amount detection method.

5 is a functional block diagram of the blast furnace pulverized coal injection amount detection and control apparatus to which the present invention is applied.

6 is a graph showing sampling data according to an embodiment of the present invention.

7 is a flowchart illustrating a blast furnace pulverized coal injection amount detection and control process according to the present invention.

 Explanation of symbols on the main parts of the drawings

1: blast furnace 2: distribution valve

2a: air mouth 3: reservoir

4: Feed Tank 4a: Blown Lance

5: nitrogen compressor 6: air compressor

11: blowing amount control unit 12: MV / V conversion unit                 

15 charge valve 16 vent valve

18: load cell 10: comparison unit

20: blowing amount detection unit 21: blowing amount calculation unit

22: Sampling number setting section 23: Sampling time setting section

24: Sampling data storage section 25: A / D conversion section

The present invention relates to a method for detecting and controlling the amount of pulverized pulverized coal blown in more detail, by using a statistical regression equation using the detected pulverized coal weight value and the weight value detection time in the pulverized coal feed tank of the blast furnace pulverized coal injection facility. The present invention relates to a blast furnace pulverized coal injection amount detection and control method for controlling the injection amount by calculating and using the result of comparing the calculated current injection amount with a target injection amount.

In general, the blast furnace operation is to charge the raw material iron ore and coke in the upper part of the blast furnace, and then blows the coke by blowing a high temperature hot air from the bottom, the iron ore is produced by molten reduction reaction by molten reduction reaction by heat and reducing gas generated at this time do. Coke, a fuel, is complicated and expensive in terms of cost, and thus, pulverized coal is injected into the furnace as a coke replacement fuel to gradually reduce the use of coke in the blast furnace operation and reduce costs.

1 is a configuration diagram of a general blast furnace pulverized coal injection facility. As shown in FIG. 1, the pulverized coal injection facility is an apparatus for crushing coal in a finely divided state and then blowing the coal into the blast furnace 1. The pulverized coal stored in the storage tank 3 is stored in a plurality of pulverized coal feed tanks 4 by a predetermined amount. After filling, pressure is charged from the nitrogen compressor 5 through blown lances 5a and 5b to a pressure higher than the pressure of the blast furnace 1 with compressed nitrogen gas. Subsequently, when the pulverized coal in the feed tank 4 is sent to the distributor 4b through the blowing lance 4a, the blast furnace distribution valve 2 is opened by the pulverized coal transfer air from the air compressor 6. It is blown into the tuyere 2a.

2 is a process chart showing a conventional blast furnace pulverized coal blowing principle. Referring to FIG. 2, the pulverized coal is supplied from the storage tank 3 to the feed tank 4 when the feed tank 4 is charged with the compressed nitrogen gas at a pressure set according to the set amount of blowing and the shutoff valve 19a is opened. In this case, the weight value detected by the feed tank load cell 18 is input to the blowing amount controller 11 through the MV / V signal converter 12, and the blowing amount controller 11 is connected to the detected blowing weight value. By comparing the target blowing weight values, the pulverized coal is blown into the blast furnace 1 through the blast furnace cutoff valve 19b by operating the charging valve 15 and the vent valve 16 connected to the feed tank, respectively.

However, in order to blow the target blowing weight required under the above operating conditions into the blast furnace 1, a sensor capable of detecting the actual blowing amount is required. However, a sensor that can directly detect the pulverized coal injection amount has been put to practical use. Indirect blow calculation method is inevitable. In particular, the conventional blow amount calculation method simply converts the weight change amount per unit time into a blow amount, and the detection time interval is reduced to 40 to reduce the blow amount signal hunting according to the signal hunting. As it is applied to the second, the delay of the detection amount of about 40 seconds occurred, so many problems exist in the blast furnace yellowing management due to the excessive variation in the amount of blow control.

3 is a flow chart showing a conventional blast furnace pulverized coal injection amount detection and control process. Referring to FIG. 3, the pulverized coal of the feed tank 4 is blown into the supply pressure of the pressure relief valve, and thus the pulverized coal reduction amount of the feed tank is detected and calculated per unit time. Therefore, in order to measure the weight of pulverized coal in the feed tank 4, the weight value of the feed tank 4 is set by the set number of data (2; M1, M2) every sampling period (typically 40 seconds) determined by the load cell 18. At the same time, the time (T1, T2) at that time is collected (S31). 4 is a graph showing the blowing amount according to the conventional blast furnace coal injection amount detection method. As shown in FIG. 4, the current blowing amount is calculated using the weight change amount within the set unit time. That is, the blowing amount controller 11 calculates based on Equation 1 below using the collected sampling data M1, M2, T1, and T2 (S32), and thus the current pulverized coal blown in the pulverized coal feed tank 4 per hour. The blowing amount is calculated (S33).

[Equation 1]

Current blowing amount = △ M / △ T = (M1-M2) / (T1-T2)

The amount of blowing calculated in this way is compared with the target blowing amount to calculate the deviation (target blowing amount-current blowing amount) of the two values (S34). If the deviation calculated in the step S34 is greater than zero, the current blowing amount is not enough compared to the target blowing amount, so that the opening degree of the filling valve 15 of the feed tank 4 is increased to increase the blowing amount by increasing the pressure. (S35). On the contrary, when the deviation is less than zero, since the current blowing amount is larger than the target blowing amount, the opening degree of the vent valve 16 of the feed tank 4 is increased to reduce the blowing amount (S37). On the other hand, if the deviation is 0, it means that the target blowing amount and the current blowing amount is the same to maintain the opening degree of the pressure-charging valve 15 and the vent valve 16 in the present state (S36).

However, in the conventional blown amount detection and control method as described above, since the error change rate of the weight signal detected by the load cell 18, which is the weight detector of FIG. The fluctuation of the amount becomes very severe, and when the time interval is increased, a stable blow amount signal can be obtained, but the detection amount is delayed because the detection is delayed by the time interval.

In order to reduce such fluctuations, the current unit time is applied to 40 seconds. However, such a long unit time can obtain a stable blow amount signal, but because it is used as a control input signal of the blow amount controller 11, there is a problem in that a bad control occurs due to time delay. Because, by adjusting the pressure control valve through the pressure controller by generating a proper control output so that the target blowing amount and the measurement blowing amount are the same, as shown in Figure 4, when the measurement delay occurs 40 seconds This is because the control operation of the final pressure control valve results in the control of the blown-off measurement value 40 seconds ago, so that control failure occurs.

The present invention has been proposed to solve the problems such as the error change rate of the blowing amount signal according to the blowing amount variation and the blowing amount control failure due to the blowing amount detection delay, the fine coal weight value detected in the feed tank And pulverized coal injection and detection, which enables stable injection control by minimizing the variation rate and detection delay time, which are the key factors of injection control, by calculating the current injection volume using statistical regression equations using the weight value detection time. The purpose is to provide a method.

The present invention for achieving the above object, the feed tank for cutting the pulverized coal to the blast furnace, the charge valve and vent valve for respectively controlling the pressure and back pressure of the pressure in the feed tank and the load cell for detecting the weight of the pulverized coal in the feed tank A blast furnace pulverized coal injection amount detection and control method in a blast furnace pulverized coal injection facility comprising: a weight value input step of receiving a pulverized coal weight value detected in the load cell; A sampling time setting step of setting a time (T) for sampling the input pulverized coal weight value; A sampling number setting step of setting a number of sampling the input pulverized coal weight value (M) according to the set sampling time; A weight value sampling step of sampling the input pulverized coal weight value M according to the set sampling time and the number of samplings; A blowing amount calculating step of calculating a current fine coal injection amount (b) in the feed tank using the sampling time (T) and the sampled weight value (M); And a valve adjusting step of adjusting the filling valve and the vent valve such that the calculated current pulverized coal injection amount b and the predetermined target injection amount B are equal to each other.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail the present invention.

5 is a functional block diagram according to the blast furnace fine coal injection amount detection and control method of the present invention. Referring to FIG. 5, first, the sampling number setting unit 22 sets the number of times of detection of the pulverized coal weight in the feed tank 4, and the sampling time setting unit 23 determines the pulverized coal weight detection time. Set it. The sampling number and sampling time of the pulverized coal weight are applied to the statistical regression equation to become an important factor for calculating the blowing amount in the current feed tank (4).

Meanwhile, in the load cell 18 installed in the feed tank 4, the weight of the pulverized coal in the feed tank 4 is measured and transmitted to the mV / V conversion unit 12. In the load cell 18, the pulverized coal weight of the feed tank 4 is measured by a special weight signal of pre-volt (mV), and the weight signal is passed through the mV / V conversion unit 12 in the injection amount detection unit 20. It is input to the A / D converter 25. The A / D converter 25 converts an analog signal into a digital signal through an A / D conversion function with respect to the input pulverized coal weight signal of the feed tank 4. The converted digital signal is input to the sampling data storage unit 24.

The sampling data storage unit 24 receives the sampling number set by the sampling number setting unit 22 and the sampling time set by the sampling time setting unit 23 according to the sampling number and the setting value of the sampling time. The pulverized coal weight value in the feed tank 4 transmitted from the A / D conversion unit 25 is sampled.

FIG. 6 is a graph showing sampling data according to an exemplary embodiment of the present invention. As shown in FIG. 6, the pulverized coal weight of the feed tank 4 is sampled ten times according to a set sampling time. FIG. 6 illustrates an example of detecting the weight of the feed tank 4 at one second intervals. In other words, the sampling time and the number of samplings of the detected weight are 1 second and 10, respectively. The blowing amount is expressed as the change in the pulverized coal weight blown into the blast furnace 1 per unit time. In other words, the blowing amount can be easily detected by using the relationship between two variables (time and weight). Therefore, as shown in FIG. 6, when the pulverized coal in the feed tank 4 is blown into the blast furnace 1, the amount of pulverized coal pulverized with time changes, that is, the weight of the pulverized coal pulverized into the sintering machine is the X axis of the time and the Y axis of the weight. It can be represented as As shown in the figure, the relationship between the two variables (time and weight) may be statistically represented by a regression equation as shown in Equation 2 below.

[Formula 2]

M = a + bT

Where M is the weight value, a M Intercept of b Is the slope of the statistical regression equation.

Therefore, since the blowing amount is represented by the change in weight (M) according to the change in time (T), the blowing amount can be obtained as shown in Equation 3 below.

[Equation 3]

Where n is the sampling number, T is the sampling time, and M is the sampling weight.                     

Referring to FIG. 5 again, as described above, the sampling data storage unit 24 samples the pulverized coal weight value of the feed tank 4 according to the set number of samplings and the set sampling time, and thus the injection amount calculating unit 21. To pass. The blowing amount calculation unit 21 applies a statistical regression equation such as Equation 2 using the sampled data (detection time and detected weight value), and calculates the blowing amount by applying Equation 3 above. The blowing amount calculated as described above is the current blowing amount blown from the feed tank 4 to the blast furnace 1.

The current blowing amount calculated by the blowing amount calculating unit 21 is input to the comparing unit 10, and the comparing unit 10 compares the input current blowing amount with a predetermined target blowing amount and compares the result. By adjusting the charge valve 15 and the vent valve 16 in accordance with this to adjust the pressure and back pressure in the feed tank (4) to control the current blowing amount. At this time, as a result of the comparison in the comparison unit 10, if the current blowing amount is larger than the target blowing amount, since the pulverized coal is injected into the blast furnace 1 from the feed tank 4, the vent valve 16 is opened to open the If the pressure of the feed tank 4 is back-pressured and the current blowing amount is smaller than the target blowing amount, less coal dust is blown into the blast furnace 1 from the feed tank 4, so that the filling valve 15 is opened. Pressurize the pressure in the feed tank (4). In this way, the current blowing amount is calculated by using the sampling data, and the current blowing amount is controlled by adjusting the filling valve 15 and the vent valve 16 so that the current blowing amount is kept the same as the target blowing amount.

7 is a flowchart illustrating a blast furnace pulverized coal injection amount detection and control process according to the present invention. First, a sampling time for sampling the pulverized coal weight value in the feed tank 4 is set (S71). In step S71, the weight value input from the load cell 18 for detecting the pulverized coal weight value in the feed tank 4 is set in advance at which time intervals. In addition, the sampling number for sampling the pulverized coal weight value in the feed tank 4 is set (S72). The step S72 is to set in advance how many times to sample the weight value inputted from the load cell 18 which detects the pulverized coal weight value in the feed tank 4.

Subsequently, the pulverized coal weight value in the feed tank 4 is received from the load cell 18 as an input (S73), and the data (T, M) according to the sampling time and the number of samplings set in the steps (S71, S72). ) Is sampled (S74). Here, T is a sampling time and M is a weight value sampled at the sampling time.

Subsequently, it is determined whether the number of weight values sampled in the step S74 is the number of samplings set in the step S72 (S75). If the number of the sampled weight values is smaller than the set sampling number, the process proceeds to step S74 to continuously sample the weight values (S74), and when the number of the sampled weight values is equal to or greater than the set sampling number, the The sampled data T and M are stored (S76).

Subsequently, using the sampled data T and M, a current blowing amount b currently blown from the feed tank 4 into the blast furnace 1 is calculated using Equations 2 and 3 above. (S77).                     

The current blowing amount b calculated in the step S77 is compared with the predetermined target blowing amount B (S78), and the process proceeds to each of the steps S79, S80, and S81 according to the comparison result.

First, when the current blowing amount (b) is greater than the target blowing amount (B) as a result of the comparison, since the present pressure is larger than the target value, the vent valve 16 is opened to back up the pressure in the feed tank 4, and When the blowing amount is reduced (S78), on the contrary, if the current blowing amount (b) is smaller than the target blowing amount (B), the pressure is insufficient to increase the pressure in the feed tank (4) because the current pressure is insufficient. Opening the valve 15 to pressurize the pressure in the feed tank 4 to increase the current blowing amount (S80). Meanwhile, as a result of the comparison, when the current blowing amount b is equal to the target blowing amount B, the current blowing amount 15 and the vent valve 16 are maintained as they are so as to be blown at the current blowing amount. (S81).

The detailed description and drawings of the present invention disclose a preferred embodiment to help understand the present invention, and do not limit the scope of the present invention, and the scope of the present invention is determined by the above detailed description. Rather, it should be determined in the appended claims.

According to the present invention, by applying a blow amount detection control method based on a statistical theory that can minimize the error of the weight change rate, as well as reducing the change rate of the blow amount and the detection time is reduced by more than five times compared to the existing detection method, stable blow amount Control is possible.                     

Further, it is possible to finally achieve a uniform pulverized coal injection into the blast furnace has a great effect in improving the quality and productivity of the molten iron through the prevention of heat fluctuations in the blast furnace and improved breathability.

The above detailed description and contents disclosed in the drawings are not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and changes can be made without departing from the spirit of the present invention. will be.

Claims (4)

A feed tank 4 for cutting pulverized coal to the blast furnace, a charge valve 15 for controlling pressurization and back pressure of the pressure in the feed tank, a vent valve 16 and a load cell 18 for detecting the pulverized coal weight in the feed tank. In the blast furnace pulverized coal injection amount detection and control method in the blast furnace pulverized coal injection facility, A weight value input step of receiving a pulverized coal weight value detected by the load cell; A sampling time setting step of setting a time (T) for sampling the input pulverized coal weight value; A sampling number setting step of setting a number n of sampling the input pulverized coal weight value M according to the set sampling time; A weight value sampling step of sampling the input pulverized coal weight value M according to the set sampling time T and the number n of sampling; Blowing amount calculation step of calculating the current pulverized coal injection amount (b) in the feed tank based on the following formula using the sampling number (n), the sampling time (T) and the sampled weight value (M) ; And And a valve adjustment step of adjusting the filling valve and the vent valve so that the calculated current pulverized coal injection amount (b) is equal to a predetermined target injection amount. [Equation]

The method of claim 1, And the sampling time (T) and the sampled weight value (M) have a relationship of the following formula. [Equation] M = a + bT (Where a is the intercept of M and b is the current pulverized coal injection) delete The method of claim 1, wherein the valve adjustment step, Comparing the current fine coal injection amount (b) with a preset target injection amount; As a result of the comparison, increasing the opening degree of the charge valve when the current pulverized coal injection amount b is smaller than the target injection amount; Increasing the opening degree of the vent valve when the current fine coal injection amount b is larger than the target injection amount; And As a result of the comparison, if the current pulverized coal injection amount (b) and the target injection amount is the same, the step of maintaining the current opening state of the pressure reducing valve and the vent valve, characterized in that the pulverized coal injection amount detection and control method.

Images