KR100362660B1 - How to Monitor Refractory Wear Condition in Refining Furnace - Google Patents

Abstract

The present invention relates to a refining furnace refractory wear condition monitoring method, and more specifically, the refinery furnace refractory wear condition monitoring to be able to monitor the wear condition of the refining furnace refractory using the molten metal and the molten metal level charged in the refining furnace It is about a method.

To this end, the present invention counts the number of refining furnace operations when the refining furnace operation start command is input, and receives the current charge amount and the melt level charged into the refining furnace to correct the melt level. Judge whether it is more than standard number. As a result, the reference melt level is corrected for the difference between the reference charge amount and the current charge amount, and the reference melt level correction value for the corrected current charge amount and the reference melt level for the reference charge amount are summed to determine the reference melt level for the current charge amount. Calculate. On the other hand, the refinement furnace exchange level correction value at the current charge amount for the difference between the reference charge amount and the current charge amount is calculated, and the refinement for the current charge amount is added by adding the calculated refinery exchange level correction value and the refiner exchange level for the reference charge amount. Calculate the exchange level with. Therefore, the difference (A) of the current charging melt level is calculated from the calculated standard melt level with respect to the current charge amount, and the difference (B) between the reference melt level and the refining furnace exchange level with respect to the current charge amount is calculated and calculated. By dividing (A) by the difference (B), the wear rate of the refractories in the refining furnace is calculated.

Description

How to Monitor Refractory Wear Status in Refineries

The present invention relates to a refining furnace refractory wear condition monitoring method, and more specifically, the refinery furnace refractory wear condition monitoring to be able to monitor the wear condition of the refining furnace refractory using the molten metal and the molten metal level charged in the refining furnace It is about a method.

1 is a process flow diagram schematically showing a general stainless steel manufacturing process. As shown in FIG. 1, the electric furnace 1 flows electric energy of three-phase alternating current to the electrode 2, the scramp, the molten metal, and the electrode 2. Dissolves the side materials to produce the molten metal. The molten metal produced in the electric furnace (10) is charged to the refining furnace (3), and is blown with a top odor using a top lance (4) and low odor using a tuyere (5). Depending on the steel grade, lattice treatment (LT) or vacuum oxygen decarburization (VOD) is performed, and finally, the slabs are produced through performance.

Figure 2 is a refractory wear phenomenon to explain the refractory wear phenomenon in the refining furnace, the refining furnace blowing operation injects oxygen (O ₂ ) in the top lance (4), O ₂ + Ar, N through the tuyere (5) Inject ₂ + Ar gas. The tuyere 5 is provided in the vicinity of the refining furnace so that the decarburization reaction occurs when the diluted gas bubbles 9 rise. In addition, the tuyere 5 is formed in a double tube structure in order to prevent melt damage, the outer part of the blown Ar / N ₂ mixed gas for cooling the tuyere, and the inner tube is blown O ₂ and Ar / N ₂ mixed gas. At this time, the molten steel in the exothermic reaction between the oxygen and the molten steel causes a large stirring (10), causing severe melting of the refractory (耐火 物) (12). In addition, when the molten steel is stirred, a violent flow 11 of the molten steel is generated, which may shorten the life of the refractory 12.

That is, the wear factor of the refining furnace refractory 12 is deeply related to the situation of refining of the refining furnace, and the refining of the refining furnace is largely divided into a decarburization step and a reduction and dewatering step. Refractory wear in the decarburization stage is caused by acidic slag wear in the electric furnace 1, mechanical wear by input of subsidiary materials, thermal wear that occurs when the refining furnace 3 becomes molten steel by the decarburization reaction, and the like. In the desulfurization step, chemical wear due to the addition of reducing agents and slag accelerators occurs.

Since the refining furnace has to be replaced due to wear of the refractory caused by these factors, the life of the refractory is directly related to the competitiveness of the refining furnace. Therefore, it is very important to monitor the condition of the refractory, and during the refining operation, the condition of the refractory should be monitored at all times to predict the life and replacement time of the refractory.

As a conventional method for monitoring the state of the refractory, for example, infrared rays are used to measure the thickness of each part of the refractory. In the method of measuring using infrared rays, the smelting furnace 3 is tilted 90 ° in the state in which there is no molten steel in the smelting furnace 3, and the thickness of each part is measured by infrared rays. However, the infrared measuring method must stop the production in order to monitor the state of the refractory, and since the refractory in the refinery 3 is measured for each part, it takes a long time and cannot monitor the state of the refractory in real time. there is a problem. In addition, the economic burden of separately purchasing an infrared meter is also entailed.

Due to this problem, in many refinery furnaces, the thickness of the refractory material after exchanging the refractory material when the refining phenomenon (phenomena which occurs just before a hole is formed in the refractory due to the wear of the molten steel) occurs in the refining furnace without using an infrared measuring instrument. And compare it with the thickness before refractory exchange, and divide the comparison result by the number of refining furnaces to calculate the refractory wear rate per refining furnace. Use a method of estimating wear.

However, in such a case, accurate wear rate information cannot be obtained because the wear state of the refractory is measured only by the number of times of refinery use without considering the amount of molten steel charged into the refinery every time the refinery is used. Even when the number of times of use is not red, the phenomenon occurs in the wall of the refining furnace frequently occurs to replace the refining furnace has a problem that can not be planned to work with the refinery.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, the object of which is to detect the wear state of the refractory by using the amount of charge charged in the refining furnace and the melt level value using the sub lance and The purpose of the present invention is to provide a refractory wear condition monitoring method that enables the operator to perform the refurbishment of the refining furnace and to proceed with the planned refining operation.

1 is a process flow diagram briefly illustrating a general stainless steel manufacturing process.

Figure 2 is a refinery furnace refractories wear phenomenon to explain the refractory wear phenomenon in the refinery operation.

Figure 3 is a block diagram showing the internal configuration of the PLC in the refinery furnace refractory wear rate monitoring device for implementing the present invention.

Figure 4 is a view showing an example of the refining furnace refining diagram for implementing the present invention.

5 is a flowchart illustrating a refractory wear rate monitoring method according to the present invention.

Explanation of symbols on the main parts of the drawings

3.refining furnace 4 ... top lance

5.Fall 12.Refractory

20 Process computer 30 Substance

40.Encoder 50 ... Refining button

60 ... Start button 100 ... PSI.

In order to achieve the above object, the refining furnace refractory wear state monitoring method according to the present invention, when a refining furnace operation start command is input, counts the number of refining furnaces used, and displays the current charging melt amount and melt level charged into the refining furnace. In the first step of receiving the input, it is determined whether the number of times of use of the refining counted in the first step is greater than or equal to the reference number for the melt level correction, and according to the result, the reference melt level is corrected for the difference between the reference charge amount and the current charge amount A third step of calculating a reference melt level for the current charge amount by adding the reference melt level correction value for the current charge amount corrected in the second step and the reference melt level for the reference charge amount, the reference charge amount and the current charge amount A fourth step of calculating a refining furnace exchange level correction value at the current charging amount for the difference of, and the refining furnace exchange level calculated in the fourth step A fifth step of calculating the refinery exchange level for the current charge amount by summing the correction value and the refinery exchange level for the reference charge amount, and inputting the first step from the reference melt level for the current charge amount calculated in the third step; The difference (A) of the received current charging level is calculated, and the difference (A) between the reference melt level and the refining furnace exchange level for the current charging amount calculated in the third and fifth steps is calculated, and the calculated difference (A) is calculated. ) Is divided into the difference (B), characterized in that it comprises a sixth step of calculating the wear rate of the refractories in the refining furnace.

Further, in the second step of the present invention, if the number of times of use as the current refining is more than the predetermined reference number, the difference between the standard charge amount and the current charge amount is multiplied by the lower melt level correction value, and the standard melt level correction value for the current charge amount is calculated. The reference melt level correction value for the current charge amount may be calculated by multiplying the difference between the reference charge amount and the current charge amount by the melt level upper limit correction value when the number of times of use as the current refining amount is less than the preset reference number.

Further, the fourth step of the present invention is characterized by calculating the difference between the reference charge amount and the current charge amount, and multiplying the calculated difference by the melt level lower limit correction value to calculate the refining furnace exchange level correction value at the current charge amount.

Hereinafter, with reference to the accompanying drawings, the configuration and operation effects of the refining furnace refractory wear state monitoring method according to an embodiment of the present invention will be described in detail.

First, the present invention is constructed by paying attention to the low or high level of the melt depending on the wear state of the refractory when charging a certain amount of molten metal in the refining furnace.

In addition, since the installation location, capacity, volume, unit volume, refractory construction method of the refining furnace, the degree of refractory wear when stirring the molten metal, and the degree of wear of the refractory by slag are different for all refining furnaces in the steel mill, for example, Pohang The structure and operation of the present invention will be described with reference to a steelmaking plant in a stainless steel mill.

Figure 3 is a view showing an embodiment of a refractory wear condition monitoring device for implementing the present invention. As illustrated in FIG. 3, the refinery furnace refractory wear state monitoring apparatus for implementing the present invention includes a refinery furnace 3 for charging a molten metal by carrying out a predetermined amount of molten metal and a melt charged into the refinery furnace 3. The sub lance 30 for measuring the temperature of the molten metal, the melt level for implementing the present invention, the encoder for detecting the moving distance of the sub lance 30, and the present invention from the user Condition data to be implemented: key setting value of refinery (3), melt level upper / lower limit correction value, refiner use frequency setting value, reference melt level setting value, refinery exchange reference melt level value A process computer 20 which receives the input and outputs the refractory wear rate and the refining furnace replacement time calculated on the screen, and receives the condition data from the process computer 20 and receives the refining furnace from the encoder 40 ( 3) molten metal The molten metal level detection signal is input, the amount of charging of the refining furnace 3 is input from a meter installed in a crane (not shown), and the wear condition of the refining furnace refractory is monitored based on the input data to determine the refining furnace replacement time and the refractory wear rate. And a programmable logic controller (PLC) 100 for outputting through the process computer 20.

On the other hand, the specification of the refining furnace (3) according to an embodiment for implementing the present invention is the capacity 90T (Ton), volume 44 ㎥, the inner diameter of the steel shell 4000mm after refractory construction. Further, the installation position of the refining furnace 3 for measuring the melt level is 6805 mm, and the installation position of the sub lance is 24772 mm. When the molten metal is charged into the refining furnace 3 and the temperature of the molten metal is measured by the sub lance 30, the encoder 40 installed in the sub lance 30 is located at the installation position of the sub lance 30 and the refining furnace 3. The molten level is calculated and input to the PLC 100 by converting the moving distance of the sub lance 30 into a current signal using the installation position as a basic factor.

The melt level when 90T of molten metal is charged into the refinery 3 is 2290 mm from the bottom of the refinery in the case of the new refinery 3, and the melt level before the refinery exchange, that is, the refinery exchange melt level is 3 ) 1810mm from the bottom. When the refractory is built in the refining furnace 3 and used immediately before the replacement, a melt level change of 2290 mm-1810 mm = 480 mm occurs for a charge amount of 90T.

Therefore, when the 90T molten metal is charged into the refining furnace 3 and the melt level is 2000 mm, the refractory wear rate is calculated. The deviation of the melt level of the new refining furnace 3 is 2290 mm-2000 mm = 290 mm, and the calculated melt level is calculated. Dividing the difference by 480mm, which is the level change of the refinery exchange molten metal, yields 290 ÷ 480 = 0.6042, which indicates that the refractory wear of the refinery 3 was advanced 60.42%.

However, since the amount of molten metal charged into the refining furnace 3 cannot always be loaded exactly 90T, the correction value accordingly is necessary. In addition, since the variation of the molten steel level also occurs depending on the number of times of use of the refining furnace 3, consideration thereof is also required. The refining furnace refractory calculation method according to the present invention will be described in detail by the configuration of FIGS. 4 and 5. do.

Figure 4 is a block diagram showing the configuration of the PearC of the present invention for implementing the above-described refractory wear rate calculation method, Figure 5 shows a flow chart for explaining the refractory wear rate calculation method according to the present invention.

First, the refining furnace according to an embodiment of the present invention, while the operation is carried out as the contents of the refractory wear is widened, when the number of times of use in the operating state is less than 100 times, a level change of 14 mm occurs with respect to the change in the melt amount of 1T, In the case of more than 100 times, as the wear rate is increased, a level change of 12 mm occurs with respect to the melt amount change of 1T, and the level change value is applied as a correction value. At this time, if the number of times of use of the refinery furnace is less than 100 times, the upper limit level of the reference charging amount (90T), that is, the melt level when the new refinery furnace 3 is used, and the correction value of 14 mm is set as the melt level upper limit correction value. In the case of correcting the refining furnace replacement level, the number of times of refining furnace use is generally more than 100 times, so 12 mm is set as the lower limit level of the standard charging amount, that is, the lower limit level correction value for correcting the refining furnace replacement level.

Thus, for example, when 100T of molten metal is charged into the refining furnace 3 having less than 100 times of use, and the molten metal level detected by the sub-lance 30 with respect to 100T currently charged is 2000 mm, the above correction is made. The wear rate of the refractory can be calculated using the values as follows.

The first subtractor 111 of FIG. 4 receives the current refining furnace charge amount and the reference charge amount measured by the meter to calculate the charge amount deviation value. That is, 100T-90T = 10T is calculated.

The comparator 120 compares the output signal of the counter 110 that counts the number of times of use of the refinery with the operation of the refinery operation start button 60 to 100 times of the setting value of the number of times of use of the refinery for correction of the melt level. The number of times of refining furnace use is determined (steps S10 and S20 of FIG. 5). At this time, the comparator 120 turns off the transistor TR by applying a low level signal to the base of the transistor TR when the frequency of use is less than 100 times, and outputs a high level signal when 100 or more times. Turn on (TR). Therefore, when less than 100 times, the relay RY is not operated and the molten metal level upper limit correction value 14mm is applied to the first multiplier 121. When the frequency is 100 or more times, the relay RY is operated so that the first multiplier ( The lower melt level correction value (12 mm) is applied to 121).

Therefore, the first multiplier 121 multiplies the molten metal charge amount deviation 10T calculated by the first subtractor 111 to the current charge amount by multiplying the molten metal level upper limit correction value (14 mm) by less than 100 times. The reference molten metal level correction value 140mm is calculated (step S30 or step S40).

The first adder 131 sums the reference melt level (2290 mm) for the reference melt amount 90T and the reference melt level correction value (140 mm) calculated by the first multiplier 121 to add the reference melt level for the current charge amount. To calculate. That is, 2290 mm + 140 mm = 2430 is calculated (step S50).

On the other hand, the second multiplier 122 multiplies the deviation 10T between the reference melt amount and the current melt amount by the melt level lower limit correction value (12 mm) to calculate the refining furnace exchange melt level correction value for the current melt amount. In other words, a refining furnace replacement melt level correction value of 10T × 12mm = 120mm is calculated for the current charging amount (step S60).

Further, the second adder 132 adds the refining furnace exchange melt level correction value (120 mm) calculated in the second multiplier 122 and the refining furnace exchange melt level (1810 mm) for the reference charging amount to refine the refilling amount. The material exchange melt level (120 mm + 1810 mm = 1930 mm) is calculated (step S70).

Next, in the second subtractor 112, the reference furnace level 2430 mm for the current charge amount calculated by the first adder 131 and the refining furnace exchange melt level (1810 mm) for the current charge amount calculated by the second adder 132. ) (2430mm-1810mm) to calculate the reference melt level deviation (500mm) with respect to the current charge amount (step S80).

The third subtractor 113 receives the melt level 2000mm of the current charged melt amount 100T measured by the sub lance 30 and the reference melt level for the current charge amount calculated by the first adder 131. (2430mm) is subtracted (2430mm-2000mm) to calculate the melt level deviation (430mm) with respect to the current charging amount (step S90).

Finally, in the divider 133, the melt level deviation (430 mm) with respect to the current charge amount calculated by the third subtractor 113 is converted into the reference melt level deviation (500 mm) with respect to the current charge amount calculated by the second subtractor 112. Division (430mm ÷ 500mm) to calculate the refractory wear rate (0.86 = 86%) (step S100). That is, it can be seen that the refractory wear rate was 86% at the time of using the refinery.

In summary, when the 90T molten metal is charged into a new refinery, the molten metal level is 2290 mm, and thus the increase of the molten level of 10T more than 90T becomes 10T × 14mm = 140mm. 2290 + 140 = 2430 mm is calculated. In addition, when the molten metal is 90T, the refinery furnace exchange melt level is 1810 mm at 100 or more times of use, so that the increase width to 10T is 10T × 12mm = 120mm, and this is about 18T of refinery exchange exchange furnace level 1810mm The sum is 1930 mm.

Therefore, when 100T of molten metal is charged into the refinery and the frequency of use of the refinery is less than 100 times, the variation of the melt level is 2430-1930 = 500mm and the current melt level of 2000T of 100T is subtracted from the maximum melt level of 2T of 100T. Thus, the level deviation is 430mm, which is divided by the maximum change of 500mm, and 430 ÷ 500 = 0.86. That is, it can be seen that the wear rate of the refractories in the refining furnace was 86%. Further, since the refractory 12 is directly connected to the life of the refining furnace 3, the life of the refining furnace is 86%.

Refining furnace refractory wear state monitoring method according to the present invention is not limited to the above-described embodiment can be carried out in various modifications within the scope of the technical idea of the present invention.

As described above, in the refining furnace refractory wear state monitoring method according to the present invention, the amount of molten metal and the level of molten metal charged into the refining furnace are detected when the refining furnace is used without simply counting the number of times of refining furnace use. By calculating the wear rate of the refractory by using the molten metal level, it is possible to provide accurate information on the degree of refractory wear and to perform the refinery furnace operation by performing the refinery exchange at the optimum time.

In addition, the refining furnace refractory wear condition monitoring method according to the present invention does not require a separate equipment for calculating the refractory wear rate can reduce the economic burden, the refractory wear rate quickly at the time when the molten metal is charged into the refining furnace The calculation provides an effect of improving productivity without affecting other post-processes in the stainless steelmaking process.

Claims (3)

A first step of counting the number of use of the refinery furnace and inputting the current charging melt amount and the melt level charged into the refinery furnace, A second step of determining whether the number of times of use of the refining counted in the first step is greater than or equal to the reference number for the melt level correction, and correcting the reference melt level for the difference between the reference charge amount and the current charge amount according to the result; A third step of calculating a reference melt level for the current charge amount by adding up the reference melt level correction value for the current charge amount corrected in the second step and the reference melt level for the reference charge amount, A fourth step of calculating a refining furnace exchange level correction value at the current charge amount with respect to the difference between the reference charge amount and the current charge amount, A fifth step of calculating the refining furnace exchange level for the current charging amount by summing the refining furnace exchange level correction value calculated in the fourth step and the refining furnace exchange level for the reference charging amount; The difference A of the current charging melt level received in the first step is calculated from the reference melt level for the current charging amount calculated in the third step, and the reference to the current charging amount calculated in the third and fifth steps. And a sixth step of calculating the difference (B) between the molten metal level and the refining furnace exchange level, and dividing the calculated difference (A) by the difference (B) to calculate the wear rate of the refining furnace refractory. Refractory wear monitoring method. The method of claim 1, wherein the second step If the number of times of use of the present refining furnace is more than the preset reference number, the reference melt level correction value for the current charge amount is calculated by multiplying the difference between the reference charge amount and the current charge amount by the melt level lower limit correction value. Refining furnace refractory wear condition monitoring method characterized in that if the current number of use of the refining furnace is less than the predetermined reference number to calculate the reference melt level correction value for the current charge amount by multiplying the difference between the reference charge amount and the current charge amount by the melt level upper limit correction value . The method of claim 1, wherein the fourth step A refinement furnace refractory wear condition monitoring method, comprising: calculating a difference between a reference charge amount and a current charge amount, and multiplying the calculated difference by a melt level lower limit correction value to calculate a refiner replacement level correction value at the current charge amount.