JP4915109B2 - Method and apparatus for monitoring effect of chemical for papermaking and method and apparatus for controlling injection amount - Google Patents

Description

  The present invention relates to a method and an apparatus for monitoring the effect of an agent for papermaking and controlling an injection amount. In particular, in the papermaking process, a method and apparatus for quickly and surely confirming the effect of the papermaking chemical added to the paper raw slurry and inlet, and a method for accurately controlling the amount of papermaking chemical injection based on the monitoring result And an apparatus.

  In addition to LBKP, NBKP, TMP, etc., as a raw material for paper, in recent years, the utilization rate of waste paper has been improved, the blending ratio of broke pulp has been improved, and the system has been closed, and used paper, DIP, coat broke, etc. Yes. These raw materials contain many anionic impurities, so-called anionic trash, and not only pitch and defects are generated by the anionic trash, but also a decrease in productivity such as paper breakage and production speed reduction.

  With respect to these problems, a method of adding cationic starch and colloidal silica (USP4388150), a method of adding bentonite in the next step after adding a synthetic cationic polymer (EP235893, JP-A-62-1191598), molecular weight The anionic trash is fixed to the pulp fiber and removed out of the system by adding various chemical agents as disclosed in a method of adding a cationic polymer having a low molecular weight and then adding an anionic polymer (Japanese Patent Publication No. 5-29719). To be done.

  Here, it is known that the particle size of the anion trash has a great influence on the fixing effect of the anion trash on the pulp. That is, when the addition of the drug becomes excessive and the anion trash aggregates to increase the particle size, the anion trash stays within the system as a result of being easily dissociated even once bonded to the pulp fiber.

  Since the particle size of such anion trash is affected by the amount of drug added, it is desirable to monitor the particle size of the anion trash in real time.

  In addition, since the particle size of the fine flocs in the pulp slurry at the inlet affects the quality (texture) of the final product, it is desirable to monitor the particle size of the fine flocs in real time.

However, conventionally, the particle size of fine flocs in anion trash and pulp slurry has not been monitored in real time, and the effect of adding chemicals has been managed intermittently by the following indirect method. .
(1) Evaluation of quality and defects of finished paper and management of production speed
(2) Measurement of particle surface charge (cation requirement) of raw slurry and inlet
(3) Turbidity measurement by transmitted light of filtrate obtained by filtering raw material slurry and inlet
USP4388150 EP235893 JP 62-191598 A Japanese Patent Publication No. 5-29719

  Each of the above conventional methods has the following problems.

(1) Evaluation of finished paper quality and defects and management of production speed:
Although the influence of the drug effect can be confirmed directly, it is management after the production has already started or after the paper has been completed, and there is a problem that the response to trouble solving is significantly delayed.

(2) Measurement of particle surface charge (cation requirement) of raw slurry and inlet:
The surface charge is merely an indirect evaluation, and the change in the surface charge and the defect caused by anion trash may not always be correlated.

(3) Measurement of turbidity of filtrate obtained by filtering raw material slurry and inlet:
It is a direct measure of turbidity due to anionic trash components, and it is highly reliable, but it requires a filtration process, so it is prone to clogging troubles in the filtration device, frequent maintenance, and equipped with a cleaning mechanism. As a result, there are many problems such as an expensive apparatus.

  The present invention solves the above-mentioned conventional problems, and a papermaking agent such as a yield improver, a drainage improver, a coagulant, and a pitch control agent added to papermaking process water such as paper raw slurry and inlet in the papermaking process. Effect monitoring method and apparatus for papermaking drug capable of quickly and surely confirming the effect of the papermaking method, and an injection amount control method for papermaking drug that accurately controls the injection amount of the papermaking drug based on such monitoring results And an apparatus.

The method for monitoring the effect of the papermaking chemical of the present invention is a method for monitoring the effect of the papermaking chemical added to the papermaking process water. A first step of irradiating the fluid under measurement with laser light amplitude-modulated (AM) at a predetermined frequency (hereinafter referred to as “modulation frequency”), and scattered light scattered by particles in the fluid under measurement; It is seen containing a second step of obtaining scattered light intensity data received by the photoelectric conversion circuit, and a third step of obtaining the particle size distribution of particles of the measured fluid based on the scattered light intensity data, the photoelectric conversion circuit Consists of a photo detector, a band pass filter and an amplifier. The optical signal of the scattered light is converted into an electric signal by the photo detector, and the modulation frequency component is converted from the electric signal to distinguish it from natural light by the band pass filter. After being amplified by the amplifier, AM detection is performed by the detection circuit, and the detected signal is output to the minimum value detection circuit. The minimum value detection circuit receives the minimum signal from the input signal after AM detection. The scattered light intensity data is obtained by detecting the signal intensity of the value .

The apparatus for monitoring the effect of the papermaking chemical of the present invention is an apparatus for monitoring the effect of the papermaking chemical added to the papermaking process water.The papermaking process water to which the papermaking chemical is added or its diluted water is used as a fluid to be measured. Laser light irradiation means for irradiating the fluid to be measured with laser light amplitude-modulated (AM) at a predetermined frequency (hereinafter referred to as “modulation frequency”), and scattered light scattered by particles in the fluid to be measured Scattered light receiving means for receiving light by a photoelectric conversion circuit, photoelectric conversion means for converting intensity data of scattered light received by the scattered light receiving means into an electric signal, and particles of the fluid to be measured based on the electric signal look including the particle size distribution presenting means for presenting the particle size distribution, the photoelectric conversion circuit, the photodetector consists of a bandpass filter and an amplifier, converted into an electric signal the optical signal of the scattered light by the photodetector In order to distinguish it from natural light by a band pass filter, the modulation frequency component signal is extracted from the electric signal, amplified by an amplifier, AM detected by the detection circuit, and the detected signal output to the minimum value detection circuit The lowest value detecting circuit detects the lowest signal intensity from the input signal after the AM detection and obtains the scattered light intensity data .

The method for controlling the injection amount of the papermaking chemical of the present invention is a method for controlling the injection amount of the papermaking chemical into the papermaking process water, the papermaking process water added with the papermaking chemical or its diluted water as the fluid to be measured, A first step of irradiating the fluid under measurement with laser light amplitude-modulated (AM) at a predetermined frequency (hereinafter referred to as “modulation frequency”), and scattered light scattered by particles in the fluid under measurement; A second step of obtaining scattered light intensity data by receiving light with a photoelectric conversion circuit ; a third step of obtaining a particle size distribution of particles in the fluid under measurement based on the scattered light intensity data; and look including a fourth step of controlling the injection amount of the papermaking agents, photoelectric conversion circuit, the photodetector consists of a bandpass filter and an amplifier, and converted into an electric signal the optical signal of the scattered light by the photodetector, Band pass In order to distinguish it from natural light by a filter, the signal of the modulation frequency component is extracted from the electric signal, amplified by an amplifier, AM detected by a detection circuit, and the detected signal is output to a minimum value detection circuit. The value detection circuit is characterized in that the scattered light intensity data is obtained by detecting the lowest signal intensity from the input signal after the AM detection .

The apparatus for controlling the injection amount of the papermaking chemical of the present invention is a device for monitoring the effect of the papermaking chemical added to the papermaking process water. The papermaking process water added with the papermaking chemical or its diluted water is used as a fluid to be measured. Laser light irradiation means for irradiating the fluid to be measured with laser light amplitude-modulated (AM) to a predetermined frequency (hereinafter referred to as “modulation frequency”), and scattering scattered by particles in the fluid to be measured Scattered light receiving means for receiving light by a photoelectric conversion circuit, photoelectric conversion means for converting intensity data of scattered light received by the scattered light receiving means into an electric signal, and particles in the fluid to be measured based on the electric signal and the particle size distribution presenting means for presenting the particle size distribution of, seen including a drug infusion control means for controlling the injection amount of the papermaking agent based on the particle size distribution, the photoelectric conversion circuit, photodetector, bandpass Filters and The optical signal of the scattered light is converted into an electric signal by a photo detector, and the signal of the modulation frequency component is extracted from the electric signal to be distinguished from natural light by a band pass filter, amplified by an amplifier, and then detected. The AM detection is performed by the circuit, and the signal after the detection is output to the minimum value detection circuit. The minimum value detection circuit detects the signal intensity of the minimum value from the input signal after the AM detection, and the scattered light intensity It is characterized by obtaining data .

  According to the present invention, the effects of papermaking agents such as a yield improver, a drainage improver, a coagulant, and a pitch control agent added to papermaking process water such as a paper raw material slurry and inlet in the papermaking process can be quickly and It is possible to confirm with certainty, and it is possible to accurately control the injection amount of the papermaking drug based on the monitoring result.

  That is, the reflection of the laser beam is related to the size of the particles that have been irradiated and hit, causing a large reflection when hitting a large particle and a small reflection when hitting a small particle. Therefore, by irradiating the fluid to be measured with laser light and measuring the intensity of the scattered light scattered by the particles in the fluid to be measured, changes in the size of particles such as anion trash in the papermaking process water (particle size Information). By using this mechanism of action, the effects of papermaking chemicals added to paper raw slurry and inlets can be monitored, and this data can be used to accurately control the chemical injection of papermaking chemicals. Can be performed.

  Hereinafter, embodiments of the present invention will be described in detail.

[Monitoring the effects of papermaking chemicals added to papermaking process water]
According to the present invention, in order to monitor the effect of the papermaking chemical added to the papermaking process water, the papermaking process water to which the papermaking chemical is added or its diluted water is used as the fluid to be measured, and laser light is applied to the fluid to be measured. Irradiated, scattered light scattered by the particles in the fluid to be measured is received to obtain scattered light intensity data, and changes in the particle size of the particles in the fluid to be measured can be captured based on the scattered light intensity data .

1) Effect monitoring apparatus for papermaking drug First, an effect monitoring apparatus for papermaking drug suitable for the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram showing a schematic configuration of a papermaking drug effect monitoring apparatus according to a preferred embodiment of the present invention, and FIG. 2 is an enlarged view showing a configuration of a laser beam irradiation unit and a scattered light receiving unit shown in FIG. FIG. In the following, the case where the paper raw slurry is measured as the papermaking process water is shown. However, as will be described later, the fluid to be measured in the present invention is not limited to the paper raw slurry, and the slurry in the inlet, press Various papermaking process waters, such as squeezed water, and its dilution water are mentioned.

  The effect monitoring apparatus for the paper-making drug includes a laser oscillator 1, a first optical fiber 2, a laser light irradiation unit 3, a scattered light receiving unit 4, a second optical fiber 5, a photoelectric conversion circuit 6, a detection circuit 7, It consists of a value detection circuit 8. Reference numeral 20 denotes a measuring tank in which the raw slurry 21 is stored. In the raw slurry 21 in the measuring tank 20, a laser disposed at the bottom of a shielding member 22 (hereinafter sometimes referred to as “sensor probe”). A light irradiation unit 3 and a scattered light receiving unit 4 are provided. The shielding member 22 shields natural light from above from reaching the measurement region 23 between the laser light irradiation unit 3 and the scattered light receiving unit 4.

  That is, as shown in FIG. 3, the shielding member 22 is a pentagonal prism having a bottom surface projecting downward and groove portions 24 formed on both projecting side surfaces. The first optical fiber 2 and the second light are formed in the groove portions 24. The fiber 5 is fixed, and the laser beam irradiating unit 3 that is one end of the first optical fiber 2 and the scattered light receiving unit 4 that is one end of the second optical fiber 5 are symmetric (line symmetric) in FIG. It is arranged. Furthermore, it is preferable that the center lines of the laser light irradiation unit 3 of the first optical fiber 2 and the scattered light receiving unit 4 of the second optical fiber 5 intersect each other at 90 degrees.

  In general, the intensity of the laser light oscillated from the laser oscillator 1 is preferably modulated so as to be distinguished from natural light. In order to return the scattered light intensity received by the photoelectric conversion circuit 6 to the original electric signal, 70 is used. A modulation of about ~ 150 kHz is preferred. Therefore, in the configuration of the present embodiment, the laser oscillator 1 includes a function generator 11 and a laser diode 12, and laser diode amplitude-modulated (AM) with a predetermined frequency, for example, 95 kHz electric signal generated from the function generator 11 is laser diode. 12 is emitted to one end of the first optical fiber 2. This laser beam is emitted from the other end of the optical fiber 2 serving as the laser beam irradiation unit 3 into the raw material slurry via the first optical fiber 2. The laser oscillator is not limited to the function generator and the laser diode, and for example, a light emitting diode or the like can be used.

  The anion trash component particles are present in the raw slurry, and the laser light applied to the anion trash component particles from the laser light irradiation unit 3 is scattered to be scattered light, thereby forming the scattered light receiving unit 4. The second optical fiber 5 is incident on the optical fiber 5 from one end thereof. In the present embodiment, the measurement region 23 is a region where the region irradiated with the laser light emitted from the laser light irradiation unit 3 and the region where the scattered light receiving unit 4 can receive the scattered light are overlapped, The light receiving unit 4 receives scattered light scattered by 90 degrees from the measurement region 23 (center line of the second optical fiber 5).

  Note that the configuration of the laser beam irradiation section in the shielding member 22 is not limited to that shown in FIG. 2, and as shown in FIG. 4, a laser diode 12 is provided in the vicinity of the measurement region 23 of the shielding member 22 and the current cable 12A is connected. The laser beam may be emitted directly in the vicinity of the measurement region of the shielding member 22, and in this case, the optical fiber is not used up to the laser beam irradiation part, thereby preventing the optical fiber from being damaged. Can do. 4, the configuration other than the laser irradiation unit is the same as that shown in FIG. 2, and members having the same functions are denoted by the same reference numerals.

  The photoelectric conversion circuit 6 includes a photo detector 61, a band pass filter 62, and an amplifier 63. The photo detector 61 connected to the other end of the second optical fiber 5 converts the optical signal of the scattered light into an electric signal. Then, in order to distinguish it from natural light by the band pass filter 62, a signal of the modulation frequency component is taken out from the electric signal, amplified by the amplifier 63 and outputted to the detection circuit 7. The photoelectric conversion circuit 6 is not limited to the one described above as long as it converts an optical signal into an electric signal. For example, a photodiode may be used instead of a photodetector, or a low-pass filter may be used instead of a bandpass filter. A pass filter may be used.

  The modulation frequency component signal is subjected to AM detection by the detection circuit 7 in order to measure the change in scattered light intensity, and the detected signal is output to the minimum value detection circuit 8. The signal output by the detection circuit 7 is subjected to signal processing equivalent to the signal passing through the low-pass filter. Accordingly, by appropriately selecting the cut-off frequency of the band-pass filter 62, the detection circuit 7 detects the signal as a DC output waveform signal from which the fluctuation of the cut-off frequency has been removed, and outputs it to the minimum value detection circuit 8. be able to. As described above, in the present embodiment, from the optical signal detected by the photodetector 61, the modulation frequency component is extracted by the bandpass filter 62, amplified by the amplifier 63, and then subjected to AM detection, whereby fine particles of anion trash component are obtained. The change in the light intensity accompanying the scattering of can be measured as the change in the signal intensity. However, AM detection is not necessarily required, and a modulation frequency component signal may be directly output to the minimum value detection circuit 8.

  The lowest value detection circuit 8 detects the lowest signal intensity from the input DC signal. This detection of the minimum value is to measure the constricted portion of the waveform, as explained by the signal waveform output from the amplifier 63 shown in FIG. The portion other than the constricted portion is when coarse paper raw material and fine anion trash component particles are present in the measurement region 23, and the constricted portion is when the paper raw material has left the measurement region. Accordingly, the minimum value detection circuit 8 detects the minimum value of the signal intensity, thereby measuring the scattered light intensity when only the fine particles of the anion trash component exist, that is, the particle size of the fine particles of the anion trash component. It becomes possible. This decrease in the minimum value indicates that the particle size of the fine particles of the anion trash component in the measurement region has decreased, and the increase in the minimum value has increased the particle size of the fine particles of the anion trash component. Represents that.

Specifically, the measurement principle of the drug effect is as follows. That is, when colloidal minute anion trash component particles (hereinafter referred to as “micro colloidal particles”) flow into and out of the measurement region 23 as the raw slurry 21 in the measurement tank 20 is agitated, fluctuations in scattered light change. Will occur. The period of this fluctuation can be estimated by assuming the measurement region as a particle and assuming the number of collisions with the micro colloidal particle. That is, when the measurement region 23 is approximated by a sphere having a diameter R and a micro colloidal particle is approximated by a sphere having a diameter r, the collision cross-sectional area Q _{0 in} this case is given by Q ₀ = π (R + r) ² . Further, when the density of the microcolloid particles is N and the relative velocity of the particles with respect to the measurement region is v, the number of times the microcolloid flows into the measurement region per unit time is ν = NQ ₀ v. Similarly, since the same fluctuation occurs when the fine colloidal particles exit the measurement region, the period of the value obtained by differentiating the scattered light intensity becomes a value twice this number. Assuming that the scattered light intensity is proportional to the nth power of the particle diameter of the fine colloidal particle, and ignoring multiple scattering, the fluctuation A of the scattered light intensity accompanying the inflow / outflow of one fine colloidal particle is A = A ₀ r ⁿ . A ₀ is a constant depending on the measurement system, and is calibrated using a standard sample.

  Here, since the micro colloidal particles have a small diameter r and a large particle density N, minute fluctuations in scattered light occur in a short cycle. Therefore, by detecting the modulation frequency component in the detection circuit 7, the output waveform is subjected to signal processing equivalent to passing through the low-pass filter as described above, and therefore the cutoff frequency of the filter 62 is appropriately selected. As a result, it can be detected as a DC signal from which this fluctuation has been removed.

  On the other hand, the paper raw material in the raw material slurry has a large fluctuation when flowing into and out of the measurement region, and the average period of the fluctuation becomes long. Therefore, when the product of the density of the paper raw material and the measurement area volume is smaller than 1, the minimum value of the output waveform after detection corresponds to the scattering of the fine colloidal particles. Thereby, in this embodiment, the minimum value detection circuit 8 is connected to the subsequent stage of the detection circuit 7, thereby distinguishing the scattered light from the fine colloidal particles in the raw material slurry, that is, the anion trash component, and the scattered light from the paper raw material, Since it becomes possible to take out only the scattered light by the anion trash component, the effect of reducing the anion trash component by the drug can be properly grasped.

  Further, in the monitoring apparatus of the present embodiment, it is not necessary to provide a special measurement unit separately, and it is possible to measure the scattered light only by putting the laser light irradiation unit and the scattered light receiving unit attached to the shielding member into the measurement tank. Therefore, a monitoring device having a simple device configuration can be provided. Furthermore, the monitoring device of this embodiment can be a throw-in type monitoring device because the device configuration is simple, lightweight, and downsized.

2) Scattered light intensity In consideration of the scattered light generated in the measurement region 23 in the apparatus shown in FIG. 1, the fine colloidal particles present in the measurement region 23 are slightly flocked by the addition of a drug. Become.

  Accordingly, when the intensity of the scattered light in the minute measurement region 23 is measured using the sensor probe having the structure described above (the shielding member 22 shown in FIG. 2), as shown in FIGS. 5 (a) to 5 (c), Aggregation progresses and the fine colloidal particles become slightly flocked, and the intensity of scattered light in the minute measurement region 23 detected by the probe increases due to the flock. Therefore, it is possible to obtain the particle size information of the minute floc by capturing the change in the scattered light intensity until the minute floc is obtained.

  The scattering intensity is handled as the standard deviation of the detection signal measured by the sensor. Displayed as electrical signal mV. Usually, a change in scattering intensity is detected relatively, and a situation where the particle size is changed large or small is detected.

3) Papermaking process water In the present invention, the papermaking process water to be measured includes paper raw material slurry and inlet. Among these, the paper raw material slurry is a raw material slurry in a normal paper pulp process, and examples of the paper raw material in the raw material slurry include LBKP, NBKP, TMP, waste paper, DIP, and coat broke. A mixture of two or more of them may be used.

4) Papermaking chemicals The papermaking chemicals added to the papermaking process water are not particularly limited, and are cationic synthetic polymers or cationic synthetic polymers and anionic synthetic polymers that are usually used in the paper pulp process. Any combination of these, amphoteric synthetic polymers, etc. can be used. The amount of these papermaking chemicals added is usually appropriately determined according to the setting conditions of the paper pulp process to be treated and the properties of the raw slurry.

5) Dilution Water and Measurement Concentration In the measurement, the papermaking process water such as raw material slurry to which a papermaking chemical is added may remain as a stock solution, or may be diluted with water as necessary and used for measurement. In other words, when the pulp fiber concentration in the papermaking process water is excessively high, the irradiation light and scattered light from the anion trash component are likely to be disturbed by the pulp fiber present in a high concentration, so that the accuracy corresponding to the anion trash component is increased. Since it may not be possible to reliably obtain a measured value, the papermaking process water is diluted as necessary. The dilution factor is not particularly limited and can be arbitrarily determined. However, the solid content concentration of the papermaking process water used for the measurement is generally preferably in the range of 500 to 60000 mg / L. It is preferable to perform dilution so as to obtain such a concentration.

  There is no restriction | limiting in particular as water for dilution, Tap water, industrial water, middle water, the pressurization flotation of the white water, or the coagulation precipitation treated water etc. can be used.

6) Flow velocity The fluid to be measured at the time of measurement may be in a fluidized state in order to prevent sedimentation of turbidity components and form a uniformly dispersed liquid, and may be stirred as necessary. The flow rate of the fluid to be measured is not particularly limited and varies depending on the concentration of the fluid to be measured. However, from the viewpoint of the stability of the measured value, 0.2 to 5.0 m / s, particularly 0.5 to The range is preferably 3.0 m / s.

7) Size of measuring unit The size of the measuring unit is such that the distance from the laser light emitting surface to the wall surface (in FIG. 1, the distance between the tip of the laser light irradiation unit 3 and the inner wall surface of the measuring tank 20) is 1 cm or more. Preferably it is. If this distance is shorter than 1 cm, reflection of laser light on the wall surface may affect the measurement value, which is not preferable.

8) Location for collecting fluid to be measured In the present invention, papermaking process water such as paper raw slurry may be extracted from a predetermined location in the paper pulp process, and measurement may be performed with an apparatus as shown in FIG. Alternatively, measurement may be performed by directly putting the shielding member 22 shown in FIG. 4 into a predetermined portion of the paper pulp process. In the case where the measurement is performed by extracting papermaking process water from the paper pulp process, it is preferable that the apparatus shown in FIG.

9) Measurement interval Measurement may be performed continuously or intermittently. The measurement frequency in the case of intermittent measurement may be arbitrarily set as long as the transition of the drug effect can be confirmed, and can be set to, for example, a measurement frequency once every 1 to 2 hours. When the measurement is not performed, for example, water may be supplied to the measurement tank to clean the laser light irradiation unit / light receiving unit described later.

10) Calibration curve Normally, as described above, the change in the scattered light intensity is relatively detected and the change in the particle size is detected. A calibration curve showing the relationship between the particle size or scattered light intensity and the measured value is prepared by measurement, and the measurement can be applied to the calibration curve to determine the particle size of the particles in the fluid to be measured. .

11) Cleaning of measuring unit It is preferable to periodically clean the laser beam irradiation unit and the scattered light receiving unit used for measurement in order to prevent a decrease in measurement accuracy due to adhesion of dirt. This irradiating part / light receiving part can be cleaned with air or water.

  In the case of cleaning with compressed air, it is performed in a gas-liquid mixed state by air diffusion in the raw material slurry that is the liquid to be measured. The cleaning time is not particularly limited, but 3 to 5 seconds is preferable for each of the laser beam irradiation unit / light receiving unit from the viewpoint of measurement stability. Although there is no particular limitation on the cleaning interval, cleaning is preferably performed at intervals of 40 to 120 seconds for each of the tencalar laser beam irradiation unit / light receiving unit for measurement stability. The washing pressure is not particularly limited, but a pressure of 0.01 MPa or more is preferable from the viewpoint of measurement stability, and more preferably 0.05 to 0.5 MPa.

  In the case of washing with water, the sensor tip is washed with high-pressure water, or fresh water is passed through the measurement tank at a flow rate of 0.5 m / second or more to clean the measurement tank and the sensor tip. The washing time is preferably about 3 to 60 seconds per time in the case of high-pressure water, and 130 seconds or more per time in the case of water flow.

12) Maintenance The apparatus of the present invention described above preferably checks the cleanliness of the laser beam irradiation unit / light receiving unit and the brightness of the irradiated laser beam at a frequency of once a month or once a week. The maintenance frequency can be arbitrarily determined according to the situation.

13) Chemical injection control of papermaking chemicals The chemical injection effect information obtained by the paper chemical effect monitoring apparatus and method of the present invention is output as an output signal, and based on this signal, chemical injection pumps and raw materials are output. It is possible to maintain the optimum chemical injection conditions by controlling the slurry feed pump.

  That is, for example, it may be used in combination with the method for increasing or decreasing the dosage from the lowest signal intensity described above, and the dosage may be increased or decreased by the information from the scattered light intensity signal of the present invention, or the scattering according to the present invention. You may control by increasing / decreasing a chemical injection amount only by the information from a light intensity signal.

  Specifically, the following chemical injection control can be performed.

  First, the scattered light intensity (mV) at the optimum chemical injection rate is measured several times and an average is taken, and the value is set as the scattered light intensity target value. When the actual measured value falls below the target value, the medicine pump output is increased according to the difference (mV) from the target value. When the actual measured value exceeds the target value, the medicinal pump output is reduced according to the difference (mV) from the target value. In this case, the measurement frequency and the range of increase / decrease can be arbitrarily determined.

  An example of a more specific medicine injection control method will be described below.

  Start paper production with normal machine operation, and achieve a stable production state with optimal dosage. At this time, the inlet sampling pipe is branched, a sensor measurement tank equipped with a sensor probe is installed, and the pipe is assembled so that the inlet after measurement returns to white water. After confirming that a predetermined flow velocity is secured in the laser emission section in the sensor measurement tank, the scattering intensity measurement is started. As an example, when measuring with a 200 mS intermittent emission laser once every 2 seconds, the scattering intensity every 2 seconds is measured for 5 minutes, and the average value of the scattering intensity is used as particle size information. The same condition is performed five times, and the average of the five particle size information is set as the control target value. Usually, this value is about 80 to 120 mV. The inverter pump output% of yield agent injection at the control target value is the current value. Here, when actual measurement value mV−control target value mV = deviation mV, for example, 0 ≦ deviation <10, the output of the inverter pump for injection of the yield agent remains the current value, and if 10 ≦ deviation <25, the inverter pump If the current output is -10%, 25≤deviation <50, the output of the inverter pump is -20%, and if 50≤dev <80, the output of the inverter pump is -30%, 80≤deviation. If it is, the output of the inverter pump is the current value −50%, and if −10 ≦ deviation <0, the output of the inverter pump is the current value + 10%, and if −25 ≦ deviation <−10, the output of the inverter pump is the current value. If the value + 15%, −50 ≦ deviation <−25, the output of the inverter pump is the current value + 20%, and if −80 ≦ deviation <−50, the output of the inverter pump is the current value + 25%, deviation ≦ −80. If so, a general program that sets the output of the inverter pump to the current value + 30% is pre-installed in the sensor, and a control signal is output from the sensor to the inverter pump, thereby controlling the chemical injection according to the particle size information. Is possible. The output frequency to the inverter pump with respect to the measurement frequency and the deviation at this time can be arbitrarily determined according to the condition fluctuation in actual manufacturing.

  Hereinafter, the present invention will be described more specifically with reference to comparative examples and examples.

In the following comparative examples and examples, the following were used as additive chemicals and papermaking process water.
1) Drug: Cationic synthetic polymer Structure / Composition: Dimethylaminoethyl acrylate methyl chloride quaternized / acrylic
Amide = 25/75 (mol%)
Intrinsic viscosity: 12 (dl / g) (Solvent = 1N NaCl (30 ° C.))
・ Use concentration: 0.2wt%
Addition rate: 0 to 5.6 mg / l (vs. slurry)
2) Papermaking process water: Inlet ・ Concentration: 7200 mg / l
・ Appearance: White slurry containing fiber

(Comparative Example 1)
The filtrate amount was measured by the following procedure.
(1) 180 ml of the inlet was put into a 500 ml beaker, and a predetermined amount of the drug was added.
(2) The mixture was stirred with a stirrer at 500 rpm for 40 seconds.
(3) The above solution (2) was immediately put into a Nutsche funnel covered with a 60 mesh nylon filter cloth, and the amount of filtered water for 10 seconds was measured.
(4) The relationship between the amount of drug added in (1) and the amount of filtrate measured in (3) is shown in FIG.

Example 1
Using the apparatus shown in FIG. 1, the scattered light intensity was measured by the following procedure.
(1) 180 ml of the inlet was put into a 500 ml beaker, and a predetermined amount of the drug was added.
(2) The mixture was stirred with a stirrer at 500 rpm for 40 seconds.
(3) A sensor probe (laser member 22 shown in FIG. 2) of laser scattered light was immersed in the liquid (2), and measurement was performed with a sensor under stirring at 250 rpm (flow rate 1.3 m / s). The measurement item was scattered light intensity, and laser light was emitted for 200 milliseconds at intervals of 2 minutes, and the average value of scattered light intensity for 120 seconds was obtained.
(4) FIG. 7 shows the relationship between the amount of drug added in (1) and the measured value of scattered light intensity obtained in (3).

  Moreover, the relationship between the filtrate amount of the comparative example 1 in the same chemical | medical agent addition amount and the measured value of the scattered light intensity of a present Example was shown in FIG.

  As is clear from FIG. 8, a clear correlation is observed between the measured value of scattered light intensity and the amount of drainage according to the present invention, and the intensity of laser light scattered by the sensor is the size of the fine floc of the inlet due to the addition of the drug. Was confirmed to be detected.

  From this result, it is understood that the effect of a drug such as a yield improver added to the inlet can be continuously monitored by measuring the scattered light intensity using the laser light scattering method sensor according to the present invention.

It is a block diagram which shows schematic structure of the effect monitoring apparatus of the papermaking chemical | medical agent which concerns on embodiment. It is an enlarged view which shows the structure of the laser beam irradiation part and scattered light light-receiving part which were shown in FIG. It is a perspective view of the shielding member 22 shown in FIG. It is an enlarged view which shows the other structural example of a laser beam irradiation part and a scattered light light-receiving part. It is a schematic diagram which shows the mode of the change of the scattered light intensity in a micro measurement area | region accompanying aggregation of a micro colloid particle. 5 is a graph showing the relationship between the amount of drug added and the amount of filtrate in Comparative Example 1. 4 is a graph showing a relationship between a drug addition amount and a measured value of scattered light intensity in Example 1. It is a graph which shows the relationship between the filtrate amount of the comparative example 1 in the same chemical | medical agent addition amount, and the measured value of the scattered light intensity of Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 1st optical fiber 3 Laser irradiation part 4 Scattered light light-receiving part 5 2nd optical fiber 6 Photoelectric conversion circuit 7 Detection circuit 8 Minimum value detection circuit 11 Function generator 12 Laser diode 20 Measurement tank 22 Shielding member 23 Measurement Region 24 Groove 61 Photodetector 62 Bandpass filter 63 Amplifier

Claims (4)

In the method of monitoring the effect of the papermaking chemicals added to the papermaking process water,
Papermaking process water to which a papermaking chemical is added or its diluted water is used as a fluid to be measured, and the fluid to be measured is irradiated with laser light amplitude-modulated (AM) to a predetermined frequency (hereinafter referred to as “modulation frequency”). The first step to
A second step of receiving scattered light scattered by particles in the fluid to be measured by a photoelectric conversion circuit to obtain scattered light intensity data;
A third step of, based on the scattered light intensity data obtaining the particle size information of particles of the measured fluid seen including,
The photoelectric conversion circuit includes a photo detector, a band pass filter, and an amplifier, converts the optical signal of the scattered light into an electric signal by the photo detector, and distinguishes it from natural light by the band pass filter. After being amplified by the amplifier, AM detection is performed by the detection circuit, and the detected signal is output to the minimum value detection circuit. The minimum value detection circuit receives the minimum signal from the input signal after AM detection. A method for monitoring the effect of a papermaking drug, wherein the scattered light intensity data is obtained by detecting the signal intensity of the value . In a device for monitoring the effect of papermaking chemicals added to papermaking process water,
Papermaking process water to which a papermaking chemical is added or its diluted water is used as a fluid to be measured, and the fluid to be measured is irradiated with laser light amplitude-modulated (AM) to a predetermined frequency (hereinafter referred to as “modulation frequency”). Laser light irradiating means,
A scattered light receiving means for receiving scattered light scattered by particles in the fluid to be measured by a photoelectric conversion circuit ;
Photoelectric conversion means for converting intensity data of scattered light received by the scattered light receiving means into an electrical signal;
And particle size information presenting means for presenting particle size data of particles of the measured fluid based on the electrical signal seen including,
The photoelectric conversion circuit includes a photo detector, a band pass filter, and an amplifier, converts the optical signal of the scattered light into an electric signal by the photo detector, and distinguishes it from natural light by the band pass filter. After being amplified by the amplifier, AM detection is performed by the detection circuit, and the detected signal is output to the minimum value detection circuit. The minimum value detection circuit receives the minimum signal from the input signal after AM detection. An apparatus for monitoring the effect of a papermaking drug, wherein the scattered light intensity data is obtained by detecting a signal intensity of a value . In the method of controlling the amount of papermaking chemicals injected into the papermaking process water,
Papermaking process water to which a papermaking chemical is added or its diluted water is used as a fluid to be measured, and the fluid to be measured is irradiated with laser light amplitude-modulated (AM) to a predetermined frequency (hereinafter referred to as “modulation frequency”). The first step to
A second step of receiving scattered light scattered by particles in the fluid to be measured by a photoelectric conversion circuit to obtain scattered light intensity data;
And a third step of controlling the injection amount of the papermaking agent based on the scattered light intensity data observed including,
The photoelectric conversion circuit includes a photo detector, a band pass filter, and an amplifier, converts the optical signal of the scattered light into an electric signal by the photo detector, and distinguishes it from natural light by the band pass filter. After being amplified by the amplifier, AM detection is performed by the detection circuit, and the detected signal is output to the minimum value detection circuit. The minimum value detection circuit receives the minimum signal from the input signal after AM detection. A method for controlling an injection amount of a papermaking drug, wherein the scattered light intensity data is obtained by detecting a signal intensity of a value . In an apparatus for controlling the amount of papermaking chemicals injected into the papermaking process water,
Papermaking process water to which a papermaking chemical is added or its diluted water is used as a fluid to be measured, and the fluid to be measured is irradiated with laser light amplitude-modulated (AM) to a predetermined frequency (hereinafter referred to as “modulation frequency”). Laser light irradiating means,
A scattered light receiving means for receiving scattered light scattered by particles in the fluid to be measured by a photoelectric conversion circuit ;
Photoelectric conversion means for converting intensity data of scattered light received by the scattered light receiving means into an electrical signal;
And a drug infusion control means for controlling the injection amount of the papermaking agent based on the electrical signal seen including,
The photoelectric conversion circuit includes a photo detector, a band pass filter, and an amplifier, converts the optical signal of the scattered light into an electric signal by the photo detector, and distinguishes it from natural light by the band pass filter. After being amplified by the amplifier, AM detection is performed by the detection circuit, and the detected signal is output to the minimum value detection circuit. The minimum value detection circuit receives the minimum signal from the input signal after AM detection. An apparatus for controlling an injection amount of a papermaking drug, wherein the scattered light intensity data is obtained by detecting a signal intensity of a value .

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