JP2004024954A - Dilution concentration correcting apparatus in caustic soda dilution system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dilution concentration correcting apparatus for keeping the concentration of a diluted and mixed solution constant all the time. <P>SOLUTION: The concentration correcting apparatus is for correcting the concentration of a diluted and mixed solution so as to keep the concentration at a prescribed value by circulating a caustic soda diluted and mixed solution stored in a diluted solution storage tank 6 through a circulation line 30 in which a circulation pump 31 and a mass flow meter 32 are arranged in series and opening or closing an automatic operation valve 44 or 54 installed in a first adjustment line 40 from a first storage tank 1 or a second adjustment line 50 from a second storage tank 7 and thus a diluted and mixed solution with a stable concentration can be obtained by using the concentration correction apparatus. Even if the temperature fluctuates considerably, the concentration alteration is in a narrow range and the concentration can be precisely as a set concentration in the case of using the solution as a production raw material to result in improvement of product precision. The apparatus may be installed in a conventional caustic soda dilution system to easily correct the diluted and mixed solution without requiring experienced skills of a worker. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is to prevent a liquid whose concentration changes depending on temperature and density, such as a caustic soda diluted mixed liquid having a predetermined concentration, from being different from a set concentration in use due to a temperature change during storage. The present invention relates to a dilution concentration correction device for a caustic soda dilution system that constantly corrects concentration.
[0002]
[Prior art]
In general, when a plurality of liquids are mixed to produce a diluted mixed liquid, the current situation is that the raw liquid supply amounts of the liquids are respectively set so as to have a predetermined concentration, and the liquids are diluted and mixed. Therefore, here, a specific example of the production of a diluted mixture of caustic soda having a preset dilution concentration by mixing a stock solution of caustic soda (common name of sodium hydroxide) and water for this dilution and mixing will be described. Caustic soda is used as a raw material for many products or as a detergent for containers, and its use is often used in the production of dyes, soaps, bleaching, pulp, petroleum refining or chemical production. At the manufacturing site of such a product, the concentration differs depending on the use, and the diluted product is used at a concentration prescribed in advance at the manufacturing plant. For this reason, at present, each manufacturing plant is provided with a manufacturing plant for diluting caustic soda to a predetermined concentration.
[0003]
FIG. 2 shows the current situation of the dilution and mixing of such a caustic soda stock solution and water as a solvent. A first storage tank 101 for storing a caustic soda stock solution having a high concentration is provided, and a supply pump 112 is provided therein. And a flow meter 113 are connected in series to form a first supply path 110, while a supply pump 122 and a flow meter 123 are connected in series to a second storage tank 107 for storing water mixed with this stock solution in the same manner as described above. Thus, the second supply path 120 is configured. Each of these paths is provided with control valves 114 and 124 for adjusting the supply amount in accordance with a preset dilution concentration, and the ends of these paths are connected to the line mixer 103 as one. I have. In the line mixer 103, the undiluted solution and water are mixed and diluted, and a diluted mixed solution having a predetermined concentration is supplied to a diluent storage tank 106.
[0004]
[Problems to be solved by the invention]
However, when mixing with such a dilution system, it is possible to dilute the mixture to the set concentration and mix. The set dilution concentration has changed, and the dilution mixture has become thinner or thicker than the set concentration. For this reason, a diluted mixture having a constant concentration has not been obtained. Also, in order to maintain the set concentration as long as possible, it is necessary to supply and mix while adjusting the respective supply amounts at the start of use, so that there is a problem that the concentration adjustment at the start requires skill. Has occurred.
[0005]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to obtain a dilution concentration correction device capable of constantly maintaining the concentration of a diluted mixed solution.
[0006]
[Means for Solving the Problems]
An object of the present invention is to connect a supply pump 12 and a flow meter 13 to a first storage tank 1 for storing a caustic soda undiluted solution, and to supply a first supply path 10 to a second storage tank 7 for storing water. The first and second supply paths 10 and 20 are connected to the line mixer 3 to obtain a diluted mixed solution, and the diluted mixed solution is connected to the line. In a caustic soda dilution system for supplying a diluent storage tank 6 connected to the mixer 3, supply pumps 42 and 52 and flow meters are respectively provided in pipes having one ends connected to the first storage tank 1 and the second storage tank 7, respectively. The first adjustment line 40 and the second adjustment line 50 having the serial connection of 43 and 53 are connected to the diluent storage tank 6, while the circulation pump 31 is stored in the diluent storage tank 6 and stored in the tank 6. A mass flow meter 32 for measuring the density and temperature of the diluted mixed solution is connected in series to circulate and supply the diluted mixed solution in the tank 6, and the density and temperature measurement signals from the mass flow meter 32 An operation signal for appropriately opening and closing the automatic operation valves 44 and 54 provided in the first adjustment line 40 and the second adjustment line 50 in response to the change in the concentration of the diluted mixed solution in the diluted solution storage tank 6. This is achieved by providing a dilution concentration correction device provided with a control unit 60 that outputs the following.
[0007]
For this purpose, in addition to the above configuration, the diluent storage tank is provided with a stirring blade 9 for stirring the caustic soda stock solution supplied from the first adjustment line 40 and the water supplied from the second adjustment line 50 therein. With the use of the dilution concentration correcting device having the stirrer, the diluted mixed solution is further stirred and the concentration becomes uniform.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIG. Reference numeral 1 denotes a first storage tank for storing a concentrated stock solution of caustic soda, and an on-off valve 11 is connected to the first storage tank 1 via a supply pipe 2. A supply pump 12 is connected to the on-off valve 11. The supply pump 12 has a flow meter 13 for measuring the supply amount of the undiluted liquid to be supplied, a control valve 14 for adjusting the supply amount of the liquid, and a check valve. 15 are connected in series via connection pipes 16 respectively. The on-off valve 11, the supply pump 12, the flow meter 13, the control valve 14, the check valve 15, and the connection pipe 16 constitute a first supply path 10. The first supply path 10 is connected to the line mixer 3. ing. Reference numeral 7 denotes a second storage tank for storing water as a solvent for diluting the caustic soda. The second storage tank 7 is also opened and closed by the supply pipe 8 of the second storage tank similarly to the first supply path 10. Valve 21 is connected. Similarly, a supply pump 22, a flow meter 23 for measuring a supply amount of water, a control valve 24 for adjusting the supply amount, and a check valve 25 are connected to the on-off valve 21 in series via a connection pipe 26. And these constitute the second supply path 20. The second supply path 20 is also connected to the line mixer 3 together with the first supply path 10, whereby the caustic soda stock solution is diluted to a predetermined concentration with water, and the caustic soda dilution mixture A liquid is obtained. The flow meters 13 and 23 provided in the first supply path 10 and the second supply path 20 may be mass flow meters as long as they measure the flow rate of the liquid flowing through the paths. It may be a flow meter.
[0009]
An automatic operation valve 5 is disposed between the line mixer 3 and a discharge pipe 4, and the discharge pipe 4 reaches a diluent storage tank 6. The diluting liquid storage tank 6 is provided with a stirrer having a stirring blade 9 for stirring the diluted caustic soda mixed liquid stored therein at a predetermined concentration. The diluent storage tank 6 is provided with a circulation line 30 through which the diluent mixture circulates between a lower part and an upper part, and a circulation pump 31 and a mass flow meter 32 are connected in series to the circulation line 30. Have been. The mass flow meter 32 measures the density and the temperature of the diluted mixed liquid, and can thereby obtain the concentration. This mass flow meter 32 is electrically connected to a separate control unit 60.
[0010]
On the other hand, the first storage tank 1 and the second storage tank 7 have on-off valves 41 and 51, supply pumps 42 and 52, flow meters 43 and 53, and automatic operation similarly to the first and second supply paths 10 and 20. First and second adjustment lines 40 and 50 are connected and connected in series with valves 44 and 54, respectively. The first and second adjustment lines 40 and 50 are connected to the diluent storage tank 6 at their terminal ends. Is connected. The automatic operation valves 44 and 54 of these adjustment lines 40 and 50 are also electrically connected to the control unit 60, and the diluted mixture in the diluent storage tank 6 circulates and the density and temperature are measured by the mass flow meter 32. When a signal enters the control unit 60, a signal indicating that the signal has risen or falls with respect to a preset density and temperature is output from the control unit 60. Then, ON and OFF operation signals are input to the automatic operation valves 44 and 54 of the first and second adjustment lines 40 and 50, and the automatic operation valves 44 and 54 are opened and closed to adjust the concentration of the diluted mixture. Has become.
[0011]
In the dilution concentration correction device configured as described above, a predetermined amount of the caustic soda solution is supplied from the first storage tank 1 so that the concentration becomes a preset concentration, and a predetermined amount of water is also supplied from the second storage tank 7 at the same time. While being mixed and diluted by the line mixer 3, the diluted mixed liquid is supplied. Thus, the diluted mixed liquid is supplied to the diluted liquid storage tank 6 until the set amount is reached. Thereafter, the stirrer operates and the stirring blade 9 rotates, so that the diluted mixed liquid in the diluted liquid storage tank 6 is stirred. The supplied diluted mixed liquid is circulated from the lower part of the tank 6 to the upper part of the tank 6 by the circulating line 31 by the circulating line 30. During the circulating feed, the diluted mixture passes through the mass flow meter 32, the density and temperature of the diluted mixture are measured, and the measurement signal is input to the control unit 60.
[0012]
During this circulating supply, the measurement signal is repeatedly input to the control unit 60. If there is no change in the density and temperature of the diluted mixture at the set concentration, the caustic soda is supplied from the first adjustment line 40 and the second adjustment line 50. No stock solution or water is supplied. On the other hand, when the actual concentration corresponding to the set concentration of the circulating diluted mixture changes, the density and the temperature change, for example, when the temperature decreases and the density decreases in proportion to this, the mass flow meter An operation signal is input from the control unit 60 according to the measurement signal from the control unit 32, and the automatic operation valve 44 of the first adjustment line 40 is opened. When the caustic soda stock solution is supplied from the first storage tank 1 and a measurement signal indicating that the density and temperature of the diluted mixed solution in the diluted solution storage tank 6 correspond to the set concentration is input, the automatic operation valve 44 is used. Is closed and the supply stops. Conversely, when the temperature rises and the density rises, an operation signal is input from the control unit 60 based on the measurement signal from the mass flow meter 32, and the automatic operation valve 54 of the second adjustment line 50 is opened. As a result, water is supplied from the second storage tank 7 and a measurement signal indicating that the density and temperature of the diluted mixed solution in the diluted solution storage tank 6 correspond to the set concentration is input. Closed and supply stopped.
[0013]
By repeating this operation, the diluted mixture maintains the set concentration. As described above, since the concentration of the diluted caustic soda is proportional to the density and the temperature, by measuring the density and the temperature of the diluted mixture, the concentration can be obtained. This is used to automatically correct the concentration of the liquid. If the concentration of liquid is related to the density and temperature in addition to caustic soda, this device can also be used for dilution correction. . Water is used as a solvent for diluting caustic soda, but when diluting a stock solution other than caustic soda, a liquid other than water may be used as the solvent.
[0014]
【The invention's effect】
As is clear from the above-described embodiment, the present invention uses a circulation line 30 in which a circulation pump 31 and a mass flow meter 32 are connected in series to circulate a caustic soda dilution mixture stored at a set concentration in a diluent storage tank 6. The automatic operation valves 44 and 54 in the first adjustment line 40 from the first storage tank 1 or the second adjustment line 50 from the second storage tank 7 are opened and closed according to the measurement signal from the mass flow meter 32. In addition, the present invention is a dilution concentration correction device that corrects the concentration of the diluted mixed solution so as to correspond to the set concentration.
[0015]
For this reason, if the temperature of a diluted mixed solution stored at a preset concentration as in the prior art changes due to a change in atmospheric temperature or the like, a change in the concentration occurs, but this phenomenon is caused by using this concentration correction device. In addition to being eliminated, a stable dilution concentration can always be obtained. In addition, even if the temperature greatly changes, the range of change in the concentration is reduced, and the set concentration can be accurately obtained when used as a raw material for production, so that the accuracy of the product is improved. Further, by arranging this dilution concentration correction device in a conventional caustic soda dilution system, the concentration of the diluted mixed solution can be easily corrected, and a special effect such that the skill of the operator becomes unnecessary can be obtained. .
[Brief description of the drawings]
FIG. 1 is a path diagram of a dilution system showing an embodiment of the present invention.
FIG. 2 is a path diagram showing a conventional dilution system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st storage tank 2 supply pipe 3 line mixer 4 discharge pipe 5 automatic operation valve 6 diluent storage tank 7 second storage tank 8 supply pipe 9 stirring blade 10 first supply path 11 opening / closing valve 12 supply pump 13 flow meter 14 control Valve 15 Check valve 16 Connection pipe 20 Second supply path 21 Open / close valve 22 Supply pump 23 Flow meter 24 Control valve 25 Check valve 26 Connection pipe 30 Circulation line 31 Circulation pump 32 Mass flow meter 40 First adjustment line 41 Open / close valve 42 supply pump 43 flow meter 44 automatic operation valve 50 second adjustment line 51 on-off valve 52 supply pump 53 flow meter 54 automatic operation valve 60 control unit

Claims (2)

A supply pump (12) and a flow meter (13) are connected to a first storage tank (1) for storing a raw solution of caustic soda to supply a first supply path (10) to a second storage tank (7) for storing water. A structure in which a pump (22) and a flow meter (23) are connected to form second supply paths (20), respectively, and the first and second supply paths are connected to a line mixer (3) to obtain a diluted mixed solution. In the caustic soda dilution system for supplying the diluted mixture to a diluent storage tank (6) connected to the line mixer,
A first adjustment line (40) in which a supply pump (42, 52) and a flow meter (43, 53) are connected in series in a pipe having one end connected to the first storage tank and the second storage tank, respectively, and a second adjustment line. An adjustment line (50) is connected to the diluent storage tank, while a circulation pump (31) is connected to the diluent storage tank, and a mass flow meter (D) for measuring the density and temperature of the diluent mixture stored in this tank. 32) are connected in series to circulate and supply the diluted mixture in this tank, and the density and temperature measurement signals from the mass flow meter are used to detect changes in the concentration of the diluted mixture in the diluent storage tank. Correspondingly, a control unit (60) for outputting an operation signal for appropriately opening and closing the automatic operation valves (44, 54) provided on the first adjustment line and the second adjustment line is provided. Dilution concentration correction Location. The diluent storage tank has therein a stirrer provided with a stirring blade (9) for stirring the caustic soda stock supplied from the first adjustment line and the water supplied from the second adjustment line. The dilution concentration correction device according to claim 1.

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