JP2003342764A - Pickling device and pickling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent excessive pickling of a strip by maintaining the liquid acid concentration in each pickling tank at a constantly adequate value, and to improve the acid regeneration efficiency and the workability in a pickling device and a pickling method. <P>SOLUTION: The liquid acid supply amount QSP<SB>0</SB>to a fifth acid circulation tank 25 is set based on the data of a steel plate S and a preset concentration value of a first acid circulation tank 21. FSP is set by correcting the liquid acid supply amount QSP<SB>0</SB>based on the difference between the preset concentration value of the fifth acid circulation tank 25 and the measured liquid acid concentration by a densitometer 78 or a steel plate transporting speed. The acid liquid supply amount QSP<SB>1</SB>to be added to the first acid circulation tank 21 is set based on the preset concentration value of the first acid circulation tank 21 and the measured acid liquid concentration by a densitometer 74, and the liquid acid supply amount QSP<SB>0</SB>is corrected. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pickling apparatus for pickling and removing oxide scale formed on the surface of a strip by pickling.

[0002]

2. Description of the Related Art Pickling treatment removes oxide scales formed on the surface of treated steel sheets such as cold-rolled steel sheets and hot-rolled steel sheets by reacting with acid solutions such as hydrochloric acid and sulfuric acid. In general continuous pickling equipment, the treated steel sheets are continuously passed through multiple pickling tanks and immersed in the acid solution stored in the pickling tank, or the acid solution is sprayed onto the treated steel sheets. The oxide scale on the surface of the steel sheet is continuously removed.

FIG. 3 schematically shows a conventional pickling apparatus.

In the conventional pickling apparatus, as shown in FIG. 3, four pickling tanks 101 to 104 are arranged in series, and the inside is filled with an acid solution for pickling the steel sheet S. Pickling tank 10
Deflector rolls 105 to 108 are provided on the entrance and exit sides of 1 to 104, respectively. Corresponding to each of the pickling tanks 101 to 104, four acid circulation tanks 109 to 112 are provided.
04 and the acid circulation tanks 109 to 112 are connected by circulation passages 117 to 120 having circulation pumps 113 to 116. In addition, a supply passage for supplying new acid liquid to each of the acid circulation tanks 109 to 112.
121 to 124 are connected, and the first to third acid circulation tanks 10
9 to 112 supply passages 121 to 123, flow meter 125 and open / close valve 126 to
128 is installed and a supply passage 124 to the fourth acid circulation tank 112
A flow meter 129 and a regulating valve 130 are attached to the. And
The acid circulation tanks 109 to 112 are connected by feed passages 134 to 136 having feed pumps 131 to 133, and the first acid circulation tank 109 is connected to the acid regeneration facility via a discharge passage 138 having a feed pump 137. It is connected to 139. Further, supply passages 140 to 143 for supplying pure water are connected to the acid circulation tanks 109 to 112, and manual opening / closing valves 144 to 147 are attached to the supply passages 140 to 143.

The control device 148 includes the circulation pumps 113 to 116, the opening / closing valves 126 to 128, the adjusting valve 130, and the feed pump 1 described above.
It is possible to control 31 to 133, 137. Further, the first acid circulation tank 109 has a densitometer 1 for measuring the concentration of the acid solution stored therein.
49 is provided, and the measurement result is input to the control device 148.

Therefore, first of all, the acid circulation tanks 109-1
Flow meter when initial acid addition to 12 (makeup)
Based on the measurement results of 125 to 129, the control device 148 controls the open / close valve 126.
~ 128 and adjusting valve 130 are opened to supply new acid liquid to each acid circulation tank 109-112, and open / close valves 144-147 are manually opened to supply pure water to each acid circulation tank 109-112. By that,
An acid solution having a predetermined concentration is stored in each of the acid circulation tanks 109 to 112. In this case, the concentration is set so that the acid solution concentration in the first acid circulation tank 109 is lower than that in the fourth acid circulation tank 112. Next, when the steel plate S is pickled, the steel plate S
The acid solution supply amount Q corresponding to the completion of the pickling with the maximum production amount is set in advance and is input to the control device 148, and the control device 148 controls the fourth acid circulation tank 112. Adjustment valve 13 so that the supply amount of the acid solution becomes the supply amount Q of the acid solution
Adjust the opening of 0. Further, the control device 148 is a circulation pump.
113-116 are driven to supply and circulate the acid solution in each acid circulation tank 109-112 to each pickling tank 101-104, and the feed pumps 131-1
33 is driven to feed the acid liquid from the fourth acid circulation tank 112 to the first acid circulation tank 109, and at the same time, the feed pump 137 is driven to feed the acid liquid from the first acid circulation tank 109 to the acid regeneration facility 139. Discharge.

In this state, the steel plate S is conveyed while being dipped in order from the first pickling tank 101 into the fourth pickling tank 104, so that the oxide scale formed on the surface of the steel plate S is cleaned and removed by the acid solution. To be done. Then, in the first acid circulation tank 109, the concentration meter 149 measures the concentration of the acid solution and outputs the measurement result to the control device 148, and the control device 148 compares the preset set concentration with the measured concentration. To calculate the corrected flow rate Y,
The correction acid supply amount F is obtained by adding or subtracting the acid supply amount Q, and the opening degree of the adjusting valve 130 is corrected.

[0008]

In the above-mentioned conventional pickling apparatus, the controller 148 adjusts the opening degree of the adjusting valve 130 so that the pickling can be completed with the maximum production amount of the steel sheet S. The supply amount Q is supplied to the acid circulation tank 112 (pickling tank 104), and the fourth
The acid solution that has been pickled in the pickling tank 104 is sequentially placed in the acid circulation tank 11
1,110,109 (pickling tank 103,102,101), while being fed, the steel sheet S is transported from the first pickling tank 101 while being immersed in the fourth pickling tank 104 for acid solution treatment. ing. However, the transport speed of the steel sheet S may need to be changed to a speed slower than the speed suitable for the pickling treatment due to the constraint of another processing step performed before and after the pickling apparatus. In this case, each pickling tank
A large amount of pickling is supplied to 101 to 104 with respect to the transport speed of the steel sheet S, and the concentration of the pickling solution increases, so that the second pickling tank 10
If the pickled steel sheet S is completed in the second or third pickling tank 103 and further passes through the fourth pickling tank 104, not only the oxide scale on the surface of the steel sheet S but also the base metal surface are removed. The problem of pickling occurs. In general, in order to prevent the acid pickling of the steel sheet S, an acid pickling inhibitor is applied to each of the acid circulation tanks 109 to 112. Since the agent is used, the material cost is increased.

When the used acid solution is processed in the acid regeneration equipment 139, the concentration of the acid solution discharged from the first acid circulation tank 109 to the acid regeneration equipment 139 is within a certain range in consideration of the processing workability. Need to maintain. Therefore, in the conventional pickling apparatus, the concentration meter 149 measures the concentration of the acid solution in the first acid circulation tank 109 and outputs the measurement result to the controller 148 to correct the acid solution supply amount Q. However, the corrected acid solution supply amount Q directly affects the concentration of the fourth pickling tank 104,
It takes a predetermined time or more before the concentration of the first pickling tank 101 is indirectly corrected. Therefore, the concentration of the acid solution discharged from the first acid circulation tank 109 to the acid regeneration facility 139 cannot be corrected to an appropriate value, the concentration of the acid solution is not stable, and the reprocessing efficiency in the acid regeneration facility 139 is reduced. Workability deteriorates.

Further, in each of the pickling tanks 101 to 104, since the temperature of the acid solution is kept higher than the ambient temperature in order to efficiently perform the pickling treatment on the steel sheet S, vaporized gaseous acid solution fumes are generated. Since it leaks into the factory, the fume ducts of the pickling tanks 101 to 104 are provided to suck the acid solution fumes. In this case, since the water content is more likely to evaporate than hydrochloric acid or sulfuric acid in the acid solution, the concentration of the acid solution in the pickling tanks 101 to 104 is increased and the steel sheet S is overpickled.

The present invention is intended to solve such a problem. By constantly maintaining the concentration of the acid solution in each pickling tank appropriately, it is possible to prevent overpickling of the strip and to improve the efficiency of the acid regeneration treatment. It is an object of the present invention to provide a pickling apparatus and method with improved workability.

[0012]

In order to achieve the above-mentioned object, a pickling apparatus according to the invention of claim 1 is provided with a plurality of pickling tanks arranged along the conveying direction of the strip and a plurality of the pickling tanks. A final pickling solution supplying means for supplying a pickling solution to a final pickling tank located on the most downstream side of the pickling tank in the carrying direction of the strip, and the most upstream of the pickling tanks in the carrying direction of the strip. A first pickling solution supplying means for supplying a pickling solution to the first pickling tank located on the side, and the final pickling solution supply based on the strip plate data and a preset reference pickling solution concentration of the first pickling tank. A reference acid solution supply amount setting means for setting an acid solution supply amount by means, and the first pickling tank from the first pickling tank.
Acid solution feeding means for feeding the acid solution to the pickling tank, acid solution discharging means for discharging the acid solution from the first pickling tank to the acid regeneration facility, and measuring the acid solution concentration in the final pickling tank A final pickling solution concentration measuring means, a first pickling solution concentration measuring means for measuring a pickling solution concentration of the first pickling tank, a reference pickling solution concentration of the final pickling tank and the final pickling solution concentration measuring means. Acid solution supply amount correcting means for correcting the acid solution supply amount set by the reference acid solution supply amount setting means based on the measured measured acid solution concentration, and a preset reference acid solution in the first pickling tank A first acid liquid supply amount setting means for setting an acid liquid supply amount by the first acid liquid supply means based on a concentration and a measured acid liquid concentration measured by the first acid liquid concentration measuring means. It is a feature.

In the pickling apparatus according to the second aspect of the present invention, the strip data includes at least the transport speed of the strip, the width of the strip, and the scale weight of the strip.

In the pickling apparatus of the invention of claim 3, the reference acid solution supply amount setting means is based on the acid solution supply quantity by the first acid solution supply means set by the first acid solution supply quantity setting means. The amount of acid solution supplied by the final acid solution supply means is corrected.

In the pickling apparatus according to the invention of claim 4, an intermediate acid for supplying an acid solution to an intermediate pickling layer between the first pickling tank and the final pickling tank among the plurality of pickling tanks. A liquid supply means, an intermediate acid solution supply position setting means for setting an intermediate pickling tank for supplying an acid solution by the intermediate acid solution supply means based on a change in the transportation speed of the strip, and a transportation speed of the strip. The acid liquid distribution amount setting means for setting the acid liquid distribution amount to be distributed to the intermediate pickling tank from the acid liquid supply amount set by the reference acid liquid supply amount setting means on the basis of the change of

In the pickling apparatus according to the invention of claim 5, the intermediate pickling liquid supply position setting means performs pickling based on the strip data, the number of pickling tanks and the length of the pickling tank. The pickling tank to be completed is estimated, and an acid solution is supplied to the pickling-completed pickling tank or the pickling-completed pickling tank and the pickling tank upstream of the pickling-completed pickling tank in the conveyance direction of the strip. It is characterized by that.

In the pickling apparatus according to the invention of claim 6, an intermediate pickling solution concentration measuring means for measuring a pickling solution concentration in the intermediate pickling tank,
The acid solution distribution amount set by the acid solution distribution amount setting means is corrected based on a preset reference acid solution concentration in the intermediate pickling tank and the measured acid solution concentration measured by the intermediate acid solution concentration measuring means. It is characterized in that an acid liquid distribution amount correction means is provided.

In the pickling apparatus according to the invention of claim 7, the acid liquid distribution amount correction means includes the acid solution supply amount set by the reference acid solution supply amount setting means and the acid solution distribution amount set by the acid solution distribution amount setting means. The feature is that the liquid distribution amount is corrected.

In the pickling apparatus according to the invention of claim 8, an acid solution fume processing means for suction-treating the acid solution fumes evaporated from each of the pickling tanks, and pure water supply for supplying pure water to each of the pickling tanks. Means, and a pure water supply amount setting means for setting the pure water supply amount by the pure water supply means based on the suction speed by the acid liquid fume processing means, the size of the pickling tank, the acid liquid concentration and the acid liquid temperature. It is characterized by the provision of.

In the pickling method according to the ninth aspect of the present invention, the pickling solution is sequentially fed to a plurality of pickling tanks, and the strip is immersed in each of the pickling tanks. In the pickling method in which the pickling process is carried out by spraying the pickling solution onto the strip while conveying the pickling solution in the direction opposite to the feeding direction, strip data and preset reference acid of the first pickling tank are set. The acid solution supply amount to the final acid solution tank is set based on the solution concentration, and the acid solution supply amount is determined based on the reference acid solution concentration of the final pickling tank and the measured acid solution concentration of the final pickling tank. While correcting, the reference acid concentration of the first pickling tank and the first pickling tank
It is characterized in that the supply amount of the acid solution to the first pickling tank is set based on the measured acid solution concentration of the pickling tank, and the supply amount of the acid solution to the final pickling tank is corrected. is there.

In the pickling method of the present invention as defined in claim 10, the intermediate acid solution tank which is presumed to have completed the pickling of the strip is specified based on the change in the transport speed of the strip, and the specified intermediate acid is specified. It is characterized in that a predetermined amount of acid solution is supplied by distributing the supply amount of the acid solution to the final acid solution tank to the washing tank and the intermediate pickling tank on the upstream side thereof.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the outline of the pickling apparatus according to one embodiment of the present invention, and FIG. 2 is a graph showing the control of the acid solution concentration in each pickling tank by the pickling apparatus of this embodiment.

In the pickling apparatus of this embodiment, as shown in FIG. 1, five pickling tanks 11 to 15 are arranged in series,
An acid solution having a predetermined concentration for pickling the steel plate (strip plate) S can be put inside, and the steel plate S flows out along the surface of the pickling tanks 11 to 15 on the inlet side and the outlet side. Ringer rolls 16 to 20 for preventing the above are provided. Each of the pickling tanks 11 to 15 (in the present embodiment, the final pickling solution tank is the fifth pickling tank 1
Five acid circulation tanks 21 to 25 are provided corresponding to 5), and the pickling tanks 11 to 15 and the acid circulation tanks 21 to 25 are provided.
And the circulation passages 31 to 35 having the circulation pumps 26 to 30.
Are connected by. In addition, each acid circulation tank 21-2
5 are connected to supply passages 36 to 40 for supplying a new acid solution (or regenerated acid solution), and a flow meter 41 and an on-off valve 46 are attached to the supply passage 36 to the first acid circulation tank 21. In the supply passages 37 to 40 from the second to the fifth acid circulation tanks 22 to 25, the flow meters 42 to 45 and the flow rate adjusting valve 4 are provided.
7 to 50 are attached. And each acid circulation tank 2
1 to 25 are feed passages 55 having feed pumps 51 to 54
The first acid circulation tank 21 is connected to the acid regeneration equipment 61 via a discharge passage 60 having a feed pump 59.

In this embodiment, the first acid solution supply means is the acid solution supply passage 36, the intermediate acid solution supply means is the acid solution supply paths 37 to 39, and the final acid solution supply means is the acid solution supply path 40. The acid solution supply means is the acid solution supply passages 55 to 58 for discharging the acid solution from the first pickling tank to the acid regeneration equipment, and the acid solution discharge means is the acid solution discharge passage 60.

Further, supply passages 62 to 66 for supplying pure water to the acid circulation tanks 21 to 25 are connected to each of the supply passages 6.
On-off valves 67 to 71 are attached to 2 to 66. A flow meter 72 and a flow rate adjusting valve 73 are attached to the base ends of the supply passages 62 to 66. Further, each of the acid circulation tanks 21 to 25 has a densitometer 74 to 78 for measuring the concentration of the acid solution.
Is provided. Further, suction ducts 79 to 83 having suction fans are provided above the pickling tanks 11 to 15, and the suction ducts 79 to 83 are connected to the acid liquid fume treatment facility 85 via the discharge passage 84. ing. In addition,
In the present embodiment, the pure water supply means includes pure water supply passages 62 to
66, the first acid solution concentration measuring means is a densitometer 74, the intermediate acid solution concentration measuring means is a densitometer 75 to 77, and the final acid solution concentration measuring means is a densitometer 78.

The controller 86 includes the circulation pumps 26 to 30,
The on-off valve 46, the flow rate adjusting valves 47 to 50, 73, the feed pumps 51 to 54, 59, and the on-off valves 67 to 71 can be controlled, and the acid circulation tanks 2 measured by the concentration meters 74 to 78 can be controlled.
An acid solution concentration of 1 to 25 is input.

In the pickling apparatus and method of this embodiment, during the pickling process when the conveying speed (line speed) of the steel sheet S is a predetermined speed, the control device 86 controls the data of the steel sheet S and the preset 1 acid circulation tank 21 (first pickling tank 11)
Based on the concentration setting value (reference acid solution concentration) of 5, the acid solution supply amount to the fifth acid circulation tank 25 (fifth pickling tank 15) is set,
The acid solution supply amount is corrected based on the concentration set value of the fifth acid circulation tank 25 and the measured acid solution concentration measured by the concentration meter 78, while the concentration set value of the first acid circulation tank 21 and the concentration meter 74 are measured. The first acid circulation tank 2 based on the measured acid concentration
The amount of acid solution supplied to No. 1 is set, and the amount of acid solution supplied to the fifth acid circulation tank 25 is corrected. Then, when the transport speed of the steel sheet S decreases (changes), it is considered that the pickling treatment of the steel sheet S is completed early. Therefore, the pickling of the steel sheet S is based on the change of the transport speed of the steel sheet S. The acid solution tank (12 to 14) estimated to be completed is specified, and the acid to the fifth acid circulation tank 25 is supplied to the specified pickling tank (12 to 14) and the pickling tank upstream thereof. The liquid supply amount is distributed to supply a predetermined amount of acid liquid.

Hereinafter, the pickling method using the pickling apparatus of the present embodiment, and each of the acid circulation tanks 21 to 21 by the control device 86.
The acid solution concentration control in 25 (pickling tanks 11 to 15) will be described in detail.

First, when the steel sheet S is pickled, the control device 86 opens the on-off valve 46 and the flow rate adjusting valves 47 to 50 to supply a predetermined amount of fresh acid solution to each of the acid circulation tanks 21 to 25. By opening the on-off valves 67 to 71 and supplying pure water to the acid circulation tanks 21 to 25,
An acid solution having a predetermined concentration is stored in 1 to 25. In this case, the concentration of the acid liquid in each of the acid circulation tanks 21 to 25 is set so that the concentration of the acid liquid decreases as the flow from the fifth acid circulation tank 25 to the first acid circulation tank 21. Then, the circulation pumps 26 to 30 are driven and the acid solutions in the acid circulation tanks 21 to 25 are supplied to the pickling tanks 11 to 15 through the circulation passages 31 to 35.
Supply circulation to. A heater is provided in each of the circulation passages 31 to 35 or each of the acid circulation tanks 21 to 25,
The acid solution is heated and maintained at a predetermined high temperature.

The controller 86 uses the steel plate S as strip data.
To the fifth acid circulation tank 25 based on the transfer speed, the width of the steel plate S, the scale weight of the steel plate S, the concentration of the new acid solution, the preset concentration setting value of the first pickling tank 11, and various coefficients. The supply amount _QSP0 of the supplied acid solution is set (reference acid solution supply amount setting means). Then, the control device 86 adjusts the opening degree of the flow rate adjusting valve 50 to supply the set acid solution supply amount Q _SP0 to the fifth acid circulation tank 25, and at the same time, supply pump 51.
~ 54 to drive the acid solution from the fifth acid circulation tank 25 to the first acid circulation tank 21 in order, and drive the feed pump 59 to drive the acid solution in the first acid circulation tank 21 to the acid regeneration facility 61. To discharge. At this time, the calculator 87 feeds back the supply amount of the acid solution measured by the flow meter 45 and adjusts the opening degree of the flow rate adjusting valve 50 so as to reduce the difference between the set supply amount of the acid solution Q _SP0. is doing.

In this state, the steel sheet S is immersed in the fifth pickling tank 15 in order from the first pickling tank 11 or conveyed while spraying an acid solution onto the steel sheet S to oxidize the surface of the steel sheet S. The scale is washed away with the acid solution.

During the pickling treatment of the steel plate S, the fifth acid circulation tar
In the tank 25, the densitometer 78 measures the concentration of the acid solution to measure the acid.
The liquid concentration is fed back to the calculator 88 of the controller 86.
This calculator 88 measures the concentration of the acid solution to be measured and the fifth acid circulation rate.
Compare the density setting value of link 25, and correct the flow rate from the difference.
Y_FiveAsk for. Then, the control device 86 controls the acid liquid supply amount F. _SP
Corrected flow rate Y_FiveIs added to correct and Y_Five= And
Output_SP0(Q_SP) Plus Y
Corrected, total acid solution supply F_SPSet (correction of acid solution supply amount)
Means).

In the first acid circulation tank 21, the concentration meter 74 measures the concentration of the acid solution and controls the measured concentration of the acid solution 86.
Is fed back to the arithmetic unit 89 of
At 9, the difference between the measured acid solution concentration and the concentration set value of the first acid circulation tank 21 is obtained, and the acid solution supply amount Q _SP1 at the time of concentration decrease is calculated. Then, while checking the measurement value of the flow meter 41, the on-off valve 46 is opened to set the acid liquid supply amount Q _SP1 to the first acid circulation tank 2
1, the acid solution supply amount Q _SP1 is fed back and subtracted from the acid solution supply amount Q _SP0 to set the entire corrected acid solution supply amount Q _SP (first acid solution supply amount setting means).

As described above, during the pickling process in which the transport speed of the steel sheet S is the predetermined speed, the fifth acid circulation tank 25 is based on the data of the steel sheet S and the concentration set value of the first acid circulation tank 21.
Set the amount Q _SP0 of acid liquid supply to the 5th acid circulation tank 25
On one of setting the F _SP to correct the acid solution supply amount Q _SP0 based on the difference between the density set value and densitometer 78 measures acid solution concentrations measured, density setting values of the first acid circulation tank 21 and the concentration 7 in total
4 sets the acid solution supply amount Q _SP1 to be added to the first acid circulation tank 21 based on the measured acid solution concentration measured by 4, and
The acid liquid supply amount Q _SP0 is corrected.

Therefore, the concentration of the acid solution in the fifth pickling tank 15 in which the steel sheet S is finally pickled, and the first pickling in which the steel sheet S is first pickled and discharged to the acid regeneration equipment 61. Tank 11
The acid solution concentration of is properly maintained. Therefore, the steel sheet S is heated in the first pickling tank 11 maintained at a predetermined low concentration and high temperature to remove a predetermined amount of scale, and in the second to fifth pickling tanks 12 to 15. It is possible to reliably remove the residual scale. Further, in the first pickling tank 11, the concentration of the acid solution is appropriately maintained, and the acid solution having a constant concentration is fed to the acid regeneration equipment 61, so that the acid regeneration treatment in the acid regeneration equipment 61 is efficiently performed. Can be done on a regular basis.

Further, during the pickling process in which the conveying speed of the steel sheet S is a predetermined speed, the entire pickling solution supply amount F _SP is corrected based on the measured pickling solution concentration of the fifth pickling tank 15, and The supply amount of the acid solution to the first pickling tank 11 is independently corrected based on the measured acid solution concentration of the pickling tank 11, and the second to fourth pickling tanks 12 are
The measured acid solution concentrations of ~ 14 are not reflected, and complicated concentration control is unnecessary.

By the way, the transport speed of the steel sheet S may be lowered due to the restriction of another processing step performed before and after the pickling apparatus. In this case, the steel sheet S is pickled in each of the pickling tanks 11 to 15. There is a risk that the time will be long and overpickling will occur. However, in actuality, a peracid pickling inhibitor is applied to each of the acid circulation tanks 21 to 25, and when all the oxide scales of the steel sheet S are removed in the pickling tanks 11 to 15 on the way, the peroxidation is prevented. The action of the anti-washing agent prevents the pickling of the base material surface and the like. However, the pickling tank on the upstream side, for example, the first to third pickling tanks 1
When the oxide scale of the steel sheet S is completely removed in 1 to 13 and the pickling is completed, consumption of the pickling solution in the pickling tank 13 where the pickling is completed and the pickling tank 12 on the upstream side is particularly heavy. As a result, the concentration of the acid solution is reduced more than necessary.

Therefore, if the conveying speed of the steel sheet S decreases,
Since the information is input to the control device 86, it is considered that the pickling treatment of the steel sheet S has been completed on the upstream side of the fifth pickling tank 15. Therefore, the control device 86 controls the conveying speed of the steel sheet S. The acid solution tank estimated to have completed the pickling of the steel sheet S based on the decrease in
A predetermined amount of the acid solution is supplied to each of the specified pickling tank and the pickling tank on the upstream side thereof to supply a predetermined amount of the acid solution.

Specifically, the control device 86 sets the acid solution tank at which the pickling of the steel sheet S is completed based on at least the transport speed of the steel sheet S, the number of acid solution tanks installed, and the acid solution concentration in each acid solution tank. Identify (intermediate acid solution supply position setting means). For example, when the pickling solution tank for which the pickling of the steel sheet S is completed is the fourth pickling tank 14 from the map based on the transport speed of the steel sheet S, the number of the pickling solution tanks, and the concentration of the pickling solution, 4 pickling tank 14 and upstream 3rd
The pickling tank 13 is specified as an additional pickling tank for the acid solution. In this case, the reason why the acid solution is supplied to the third pickling tank 13 on the upstream side as well as the fourth pickling tank 14 where the pickling has been completed is the fourth reason.
This is because when the pickling is completed on the upstream side of the pickling tank 14, it is considered that the third pickling tank 13 has sufficiently consumed the acid solution.

The fourth pickling tank 14 and the third pickling tank 13
Is specified as an additional pickling tank for the acid solution, the same as above
In addition, the conveyance speed of the steel sheet S, the number of acid solution tanks installed,
The fifth pickling tank 15 (fifth acid circulating tank)
Acid liquid supply amount F to the tank 25) _SPDistribute the third and fourth acids
Amount of acid solution supplied to the washing tanks 13 and 14, and each pickling tank 1
Set the distribution ratio of 3,14 (acid liquid distribution amount setting means)
It That is, the control device 86 is the third that additionally supplies the acid solution,
Of the flow rate adjusting valves 48, 49 of the fourth acid circulation tanks 23, 24
By adjusting the opening, the distributed acid liquid supply amount can be adjusted to the third,
Supply to the fourth acid circulation tank 24, 25. At this time
The calculators 92 and 93 supply the acid solution measured by the flow meters 43 and 44.
The amount is fed back and compared with the set acid liquid supply amount.
The opening of the flow rate adjusting valves 48, 49 so that the difference between the two decreases.
Adjust.

At this time, in the third and fourth acid circulation tanks 23 and 24, the densitometers 76 and 77 measure the acid solution concentration and feed back the measured acid solution concentration to the calculators 95 and 96 of the controller 86. The arithmetic units 95 and 96 compare the measured acid liquid concentration with the concentration set values of the third and fourth acid circulation tanks 23 and 24, and obtain the corrected flow rates Y ₃ and Y ₄ from the difference between them and output them. To do. Controller 86, the correction flow rate Y _3, Y ₄ third based on, together with the acid solution supply amount supplied to the fourth acid circulation tank 24 and 25 to correct (acid liquid dispensing amount correcting means),
The correction flow rates Y ₃ and Y ₄ are integrated to calculate the total correction flow rate Y, and Y is added to the acid solution supply amount Q _SP to obtain the total acid solution supply amount F.
Set _SP . In this case, the third and fourth acid circulation tanks 2
The corrected flow rates Y ₃ and Y ₄ obtained by comparing the set concentration values of 3, 24 and the measured acid solution concentration are used as the third and fourth acid circulation tanks 2.
A distributor for supplying acid solution supply amount 4, 25, by reflecting the total acid solution supply amount F _SP, by learning the deviation of the total acid fluid supply amount F _SP by the supply amount correction, the controller 86
This improves the accuracy of various setting calculations.

When the conveying speed of the steel sheet S is reduced from the predetermined speed in this way, the pickling treatment of the steel sheet S is performed by the fifth pickling tank 1.
Since it may be completed earlier on the upstream side than 5, the intermediate acid solution tanks 12 to 14 which are presumed to have completed the pickling of the steel sheet S based on the decrease in the transport speed of the steel sheet S are specified. Then, the supply amount F _SP of the acid solution to the fifth acid circulation tank 25 is distributed to the specified pickling tank and the pickling tank on the upstream side thereof to supply a predetermined supply amount of the acid solution and a concentration meter. 76,7
The measured acid solution concentration of 7 is fed back to correct the supply amount of the acid solution to be distributed to the specified intermediate acid solution tank.

Therefore, the acid solution is supplied only to the intermediate pickling tank in which the removal of the oxide scale of the steel sheet S is completed early due to the decrease in the transport speed of the steel sheet S and the acid solution concentration is reduced more than necessary. In addition, it is possible to eliminate unnecessary supply of the acid solution, and it is possible to promptly correct the pickling tank whose acid solution concentration is lowered more than necessary to a predetermined acid solution concentration. By constantly maintaining the liquid concentration appropriately, it is possible to prevent overpickling and prevent an increase in material cost due to the large use of an acid solution or a perpickling inhibitor.

Furthermore, during the above-mentioned pickling process of the steel sheet S, each circulation passage 31 to 35 or each acid circulation tank 21 to
25, the steel sheet S is heated by a heater for the purpose of efficiently performing pickling, and the pickling solution temperature is kept at a high temperature that has the highest pickling effect. Suction ducts 79 to 83 for sucking liquid fumes by a suction fan
And is fed to the acid solution fume treatment facility 85 through the discharge passage 84 for processing. However, each pickling tank 11
In Nos. 15 to 15, more water is evaporated than in hydrochloric acid and sulfuric acid in the acid solution, so that the concentration of the acid solution in the pickling tanks 11 to 15 is increased. Therefore, this acid liquid fume processing equipment 8
5, the pure water supply amount to each of the pickling tanks 11 to 15 is set (pure water supply amount setting means) based on the suction speed, the size of the pickling tanks 11 to 15, the acid solution concentration, and the acid solution temperature. A predetermined amount of pure water is supplied to each pickling tank 11-15.

In this case, since the suction fan is normally driven by a constant speed motor, the suction amount of the acid liquid fumes in the suction ducts 79 to 83 is constant with respect to the vapor pressure in the pickling tanks 11 to 15. Therefore, it is sufficient to replenish a fixed amount of water vaporized, and the open / close valves 67-71 of the pure water supply passages 62-66.
By opening the valve, it is sufficient to replenish the acid circulation tanks 21 to 25 with pure water containing only water that evaporates in the pickling tanks 11 to 15, and based on the measured value of the flow meter 72, the opening degree of the flow rate adjusting valve 73 It is possible to control and increase the accuracy of the supply amount.
In this case, the evaporation amount of the acid liquid is calculated on the assumption that the evaporated acid liquid fumes are all sucked from the liquid surfaces of the pickling tanks 11 to 15 by the suction ducts 79 to 83, and the amount of water corresponding to the evaporated amount is set.

Specifically, the Reynolds number Re obtained from the flow velocity, density and viscosity of air, the diffusion coefficient and the Schmidt number.
There is a general graph in which the vapor pressure and the evaporation amount can be related by using the relational expression with the heat transfer j factor jD of Corban determined from Sc. Therefore, the evaporation amount of water from the liquid surface of the acid liquid can be calculated by obtaining the partial pressure of water vapor in the air. For example, it can be determined from the suction flow rate of vapor by a suction fan, the concentration of the acid solution in the pickling tanks 11 to 15, the temperature of the acid solution, the total length and the entire width. However, since this amount varies depending on the shapes of the pickling tanks 11 to 15, the shapes of the suction ducts 79 to 83, and the installation conditions, it is necessary to review the past results in consideration.

Therefore, it is possible to maintain the concentration of the acid solution in each of the pickling tanks 11 to 15 at a predetermined value, prevent over-pickling of the steel sheet S due to an increase in the concentration of the acid solution, and contribute to a stable pickling process. be able to.

As described above, with the pickling apparatus and method of this embodiment, the concentration of the acid solution in each of the pickling tanks 11 to 15 can be constantly maintained at a predetermined value, which is also the case in the graph shown in FIG. It is clear that the fluctuations in the concentration of the acid solution in the pickling tanks 11 to 15 can be maintained within a minute range.

In the above-described embodiment, the pickling apparatus of the present invention has five pickling tanks 11 to 15 (the acid circulation tanks 21 to 21).
25) are arranged in series, but the present invention is not limited to this number, and the width of the strip, the scale weight, the transport speed of the strip, the acid solution concentration, the size of the pickling tank, and the like. It may be appropriately set according to the installation place and the like, and if it is three or more pickling tanks (acid circulation tanks), the same effects as those of the above-described embodiment can be obtained.

The first acid solution supply means, the intermediate acid solution supply means, and the final acid solution supply means of the present invention supply the acid solution to each pickling tank, but as described in the embodiment, A new acid solution is supplied to each of the acid circulation tanks 21 to 25 and circulated between each of the acid circulation tanks 21 to 25 and each of the pickling tanks 11 to 15, or each of the acid circulation tanks 21 to 25 is used. Alternatively, a fresh acid solution may be directly supplied to each of the pickling tanks 11 to 15.

[0052]

As described above in detail in the embodiments, according to the pickling apparatus of the invention of claim 1, a plurality of pickling tanks are arranged along the conveying direction of the strip, and A final pickling solution supplying means for supplying the pickling solution to the final pickling tank located on the most downstream side in the conveying direction, and a first pickling solution supplying means for supplying the pickling solution to the first pickling tank located on the most upstream side. And an acid liquid feeding means for feeding the acid liquid from the final pickling tank to the first pickling tank, and
Acid solution discharging means for discharging the acid solution from the pickling tank to the acid regeneration facility, final acid solution concentration measuring means for measuring the acid solution concentration in the final pickling tank, and measuring the acid solution concentration in the first pickling tank The first acid solution concentration measuring means is provided, and the reference acid solution supply amount setting means uses the strip plate data and the preset reference acid solution concentration of the first pickling tank to supply the acid solution supply amount by the final acid solution supply means. And the acid solution supply amount correcting means corrects the acid solution supply amount set by the reference acid solution supply amount setting means on the basis of the reference acid solution concentration in the final pickling tank and the measured acid solution concentration. Acid solution supply by the first acid solution supply means based on the reference acid solution concentration of the first pickling tank in which the acid solution supply amount setting means is preset and the measured acid solution concentration measured by the first acid solution concentration measuring means Since the amount is set, the acid solution concentration in the final pickling tank where the strip is pickled last, and when the strip is pickled first Since the acid solution concentration of the first pickling tank discharged to the acid regeneration equipment is properly maintained, the strip is heated in the first pickling tank maintained at a predetermined low concentration and high temperature. By removing a predetermined amount of scale, the scale that remains after the second pickling tank can be reliably removed, and by supplying a constant concentration of acid solution to the acid regeneration facility,
The acid regeneration treatment in the acid regeneration equipment can be performed efficiently,
As a result, by constantly maintaining the concentration of the acid solution in each pickling tank, it is possible to prevent overpickling of the strip and improve the acid regeneration treatment efficiency and workability.

According to the pickling apparatus of the second aspect of the present invention, since the strip data is at least the transport speed of the strip, the width of the strip, and the scale weight of the strip, the acid solution to the final acid solution tank is used. The supply amount can be set with high accuracy.

According to the pickling apparatus of the invention of claim 3, the reference acid solution supply amount setting means is based on the acid solution supply amount by the first acid solution supply means set by the first acid solution supply amount setting means. Since the amount of acid solution supplied by the final acid solution supply means is corrected, the amount of acid solution supplied from the first pickling tank is reflected in the amount of acid solution supplied from the final pickling tank to be corrected. By maintaining the above, proper pickling treatment can be carried out.

According to the pickling apparatus of the invention of claim 4, the intermediate pickling solution for supplying the pickling solution to the intermediate pickling layer between the first pickling tank and the final pickling tank among the plurality of pickling tanks. Based on the supply means, the intermediate acid solution supply position setting means for setting the intermediate pickling tank for supplying the acid solution by the intermediate acid solution supply means based on the change in the transfer rate of the strip, and the change in the transfer rate of the strip. Since the acid solution distribution amount setting means for setting the acid solution distribution amount to be distributed to the intermediate pickling tank from the acid solution supply amount set by the standard acid solution supply amount setting means is provided by the reference acid solution supply amount setting means The acid solution is supplied only to the intermediate pickling tank where the scale removal is completed early and the acid solution concentration has dropped more than necessary, so it is possible to eliminate the need for wasteful supply of the acid solution and the acid solution concentration. Can be corrected at an early stage, and by constantly maintaining the acid solution concentration in each pickling tank properly, An increase in material cost due to use of a large amount of to prevent washing acid solution and Kasan'arai inhibitor can be prevented.

According to the pickling apparatus of the fifth aspect of the present invention, the intermediate pickling liquid supply position setting means completes pickling based on the strip data, the number of pickling tanks and the length of pickling tanks. The pickling tank is estimated, and the acid solution is supplied to the pickling tank that is upstream of the pickling completed pickling tank or pickling completed pickling tank and pickling completed pickling tank. It is possible to reliably identify the pickling tank in which the removal of the oxide scale is completed due to the decrease in the transportation speed.

According to the pickling apparatus of the invention of claim 6, an intermediate pickling solution concentration measuring means for measuring the pickling solution concentration of the intermediate pickling tank,
Acid solution distribution that corrects the acid solution distribution amount set by the acid solution distribution amount setting means based on a preset reference acid solution concentration in the intermediate pickling tank and the measured acid solution concentration measured by the intermediate acid solution concentration measuring means Since the amount correcting means is provided, the concentration of the acid solution in the specific pickling layer for supplying and distributing the acid solution can be maintained with high accuracy.

According to the pickling apparatus of the seventh aspect of the invention, the acid liquid distribution amount correction means includes the acid liquid supply amount set by the reference acid liquid supply amount setting means and the acid liquid distribution amount set by the acid liquid distribution amount setting means. Since the distribution amount is corrected, the correction value of the supply amount of the acid solution distributed and supplied to the specific pickling layer is reflected in the total supply amount of the acid solution and the individual distribution amount of the acid solution to make the correction. The acid solution concentration of can be maintained with high accuracy.

According to the pickling apparatus of the invention of claim 8, an acid solution fume processing means for suction-treating the acid solution fumes evaporated from each pickling tank, and pure water supply for supplying pure water to each pickling tank Means, and a pure water supply amount setting means for setting the pure water supply amount by the pure water supply means based on the suction speed by the acid liquid fume processing means, the size of the pickling tank, the concentration of the acid solution and the temperature of the acid solution. Therefore, the concentration of the acid solution in each pickling tank can be maintained at a predetermined value, and overpickling of the strip due to an increase in the concentration of the acid solution can be prevented to contribute to a stable pickling treatment.

According to the pickling method of the invention of claim 9, the pickling solution is sequentially fed to a plurality of pickling tanks, the strip is immersed in each pickling tank, or each pickling tank is picked up. When the pickling process is carried out by spraying the pickling solution on the strip in the inside and carrying it in the direction opposite to the feeding direction of the pickling solution, the strip plate data and the preset reference pickling solution concentration of the first pickling tank are set. Based on the standard acid solution concentration of the final pickling tank and the measured acid solution concentration of the final pickling tank, the acid solution supply rate is corrected based on The acid solution supply amount to the first pickling tank is set based on the reference acid solution concentration of the pickling tank and the measured acid solution concentration of the first pickling tank, and the acid solution supply amount to the final pickling tank is set. Since the correction is made, the acid solution concentrations of the final pickling tank and the first pickling tank are properly maintained, so that the strip is maintained at a predetermined low concentration and high temperature.
Heated in the pickling tank to remove a certain amount of scale,
It is possible to reliably remove the scale remaining after the pickling tank, and it is possible to efficiently carry out the acid regeneration treatment in the acid regeneration equipment by feeding the acid regeneration equipment with a constant concentration of the acid solution. As a result, the concentration of the acid solution in each of the pickling tanks can always be properly maintained to improve the efficiency of acid regeneration treatment and workability.

According to the pickling method of the tenth aspect of the present invention, the intermediate acid liquid tank which is estimated to have completed the pickling of the strip is specified based on the change in the transport speed of the strip, and the specified intermediate acid is specified. Since the supply amount of the acid solution to the final acid solution tank is distributed to the washing tank and the intermediate pickling tank on the upstream side to supply a predetermined amount of the acid solution, it is possible that the conveyance speed of the strip decreases. The acid solution is supplied only to the intermediate pickling tank in which the removal of the oxide scale is completed early and the acid solution concentration has dropped more than necessary, and it is possible to eliminate the need for wasteful supply of the acid solution. The concentration can be corrected at an early stage, and by constantly maintaining the concentration of the acid solution in each pickling tank properly, it is possible to prevent overpickling and reduce the material cost due to the large use of acid solution and overpickling inhibitor. The increase can be prevented.

[Brief description of drawings]

FIG. 1 is a block configuration diagram schematically showing a pickling apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing acid solution concentration control in each pickling tank by the pickling apparatus of the present embodiment.

FIG. 3 is a schematic view of a conventional pickling apparatus.

[Explanation of symbols]

11 1st pickling tank 12 2nd pickling tank 13 3rd pickling tank 14 4th pickling tank 15 5th pickling tank (final pickling tank) 21 1st pickling circulation tank 22 2nd pickling circulation tank 23 3 acid circulation tank 24 4th acid circulation tank 25 5th acid circulation tank 31-35 circulation passages 36-40 acid liquid supply passages 41-45 are flowmeters 46 open / close valves 47-50 flow adjustment valves 55-58 acid liquid supply Passage 61 Acid regeneration equipment 62-66 Pure water supply passage 67-71 Open / close valve 63 Flow rate adjusting valve 74-78 Concentration meter 79-83 Suction duct 85 Fume processing equipment 86 Control device (reference acid liquid supply amount setting means, acid liquid supply) Amount correction means, first acid liquid supply amount setting means, intermediate acid liquid supply position setting means, acid liquid distribution amount setting means, acid liquid distribution amount correction means,
Pure water supply amount setting means)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4K053 PA02 PA12 QA01 RA14 SA06                       TA16 TA24 XA24 YA02 YA03                       YA04 YA23 YA25 YA28

Claims (10)

[Claims] 1. A plurality of pickling tanks arranged along the strip conveying direction, and a final pickling tank located on the most downstream side of the strip picking direction in the strip conveying direction. A final pickling solution supplying means for supplying the solution, and a first pickling solution supplying means for supplying the pickling solution to the first pickling tank located on the most upstream side of the plurality of pickling tanks in the transport direction of the strip, Reference acid solution supply amount setting means for setting the acid solution supply amount by the final acid solution supply means based on the strip plate data and the preset reference acid solution concentration of the first pickling tank, and the final pickling tank From the first pickling tank to the acid regeneration facility, and an acid solution discharging means to discharge the acid solution from the first pickling tank to the acid regeneration facility; Final acid solution concentration measuring means for measuring solution concentration, first acid solution concentration measuring means for measuring acid solution concentration in the first pickling tank, and reference acid in the final pickling tank Acid solution supply amount correcting means for correcting the acid solution supply amount set by the reference acid solution supply amount setting means based on the solution concentration and the measured acid solution concentration measured by the final acid solution concentration measuring means, and preset. A first acid for setting the amount of acid solution supplied by the first acid solution supply means based on the reference acid solution concentration of the first pickling tank and the measured acid solution concentration measured by the first acid solution concentration measuring means A pickling apparatus comprising: a liquid supply amount setting means. 2. The strip data according to claim 1,
A pickling apparatus having at least a conveying speed of the strip, a width of the strip, and a scale weight of the strip. 3. The final acid according to claim 1, wherein the reference acid solution supply amount setting means is based on the acid solution supply amount by the first acid solution supply means set by the first acid solution supply quantity setting means. A pickling apparatus, which corrects the amount of the acid solution supplied by the solution supply means. 4. The intermediate pickling solution supply means for supplying an pickling solution to an intermediate pickling layer between the first pickling tank and the final pickling tank among the plurality of pickling tanks according to claim 1. An intermediate acid solution supply position setting means for setting an intermediate pickling tank for supplying an acid solution by the intermediate acid solution supply means based on a change in the transfer speed of the strip, and a change in the transfer speed of the strip The pickling apparatus is provided with an acid solution distribution amount setting means for setting an acid solution distribution quantity to be distributed to the intermediate pickling tank from the acid solution supply quantity set by the reference acid solution supply quantity setting means. 5. The pickling method according to claim 4, wherein the intermediate pickling solution supply position setting means completes pickling based on the strip data, the number of pickling tanks and the length of the pickling tanks. A tank is estimated, and an acid solution is supplied to the pickling-completed pickling tank or the pickling-completed pickling tank and the pickling tank upstream of the pickling-completed pickling tank in the conveyance direction of the strip. Pickling equipment to do. 6. The intermediate acid solution concentration measuring means for measuring the acid solution concentration of the intermediate pickling tank according to claim 4, the preset reference acid solution concentration of the intermediate pickling tank, and the intermediate acid solution concentration. A pickling apparatus comprising: an acid liquid distribution amount correcting means for correcting the acid liquid distribution amount set by the acid liquid distribution amount setting means based on the measured acid liquid concentration measured by the measuring means. 7. The acid solution distribution amount correction means according to claim 6, wherein the acid solution supply amount set by the reference acid solution supply amount setting means and the acid solution distribution amount set by the acid solution distribution amount setting means are set. A pickling device characterized by correction. 8. The acid solution fume processing means for sucking the acid solution fumes evaporated from each of the pickling tanks, and the pure water supply means for supplying pure water to each of the pickling tanks according to claim 1.
A pure water supply amount setting means for setting the pure water supply amount by the pure water supply means based on the suction speed by the acid liquid fume processing means, the size of the pickling tank, the acid liquid concentration and the acid liquid temperature was provided. A pickling device characterized in that 9. An acid solution is sequentially fed to a plurality of pickling tanks to immerse the strip in the acid solution in each of the pickling tanks, or in each of the pickling tanks. In the pickling method in which the pickling treatment is carried out by conveying the pickling solution in a direction opposite to the feeding direction of the pickling solution, the final picking method is performed based on the strip plate data and the preset reference pickling solution concentration of the first pickling tank. Set the amount of acid solution supplied to the acid solution tank,
While correcting the supply amount of the acid solution based on the reference acid solution concentration of the final pickling tank and the measured acid solution concentration of the final pickling tank, the reference acid solution concentration of the first pickling tank and the first acid solution are corrected. The pickling solution is characterized in that the amount of the acid solution supplied to the first pickling tank is set on the basis of the measured acid solution concentration in the pickling tank, and the amount of the acid solution supplied to the final pickling tank is corrected. Method. 10. The intermediate pickling solution tank according to claim 9, wherein the intermediate pickling solution tank, which is estimated to have completed the pickling of the strip, is specified based on the change of the transport speed of the strip, and the specified intermediate pickling tank and its A pickling method, characterized in that a predetermined amount of the acid solution is supplied to each of the intermediate pickling tanks on the upstream side by distributing the supply amount of the acid solution to the final pickling solution tank.