JP6027564B2 - Method and apparatus for measuring oil content in water to be treated - Google Patents

Description

  The present invention relates to the quality of water to be treated at a water treatment site, in particular, an oil content measuring method and an oil content measuring device for measuring oil content remaining in accompanying water or waste water, that is, residual oil content.

  As what measures oil content, Unexamined-Japanese-Patent No. 2013-24562 (patent document 1) is known, for example. In Patent Document 1, a quartz crystal microbalance (hereinafter referred to as “QCM”) is used, and water-soluble ink as a measurement target is dropped on a crystal resonator by inkjet, before droplet dropping. The mass of the adhering substance on the crystal unit, that is, the water-soluble ink is measured based on the resonance frequency (basic frequency) of the crystal unit and the amount of change in the resonance frequency measured after dropping the droplet. In other words, a minute amount of oil in the sample water is measured using the change in the resonance frequency (also referred to as the natural frequency) and the characteristics of the amount of adhesion on the surface.

JP2013-24562A

  However, in the configuration of Patent Document 1, the water-soluble ink to be measured is directly dropped onto the crystal resonator, and the mass of the oil in the water-soluble ink is measured. Inclusion is included in the measurement.

  Therefore, for example, no consideration is given to the measurement of the accompanying water containing a very small amount of oil at the site of Oil & Gas, or the small amount of oil contained in domestic wastewater or industrial wastewater. That is, it is difficult to apply to the measurement of oil contained in the water to be treated, which is defined by the official method (Water Pollution Control Act).

  An object of the present invention is to provide an oil content measuring method and an oil content measuring device capable of measuring the oil content remaining in the water to be treated at a water treatment site with high accuracy.

In order to solve the above-described problems, an oil content measurement method of the present invention includes a solvent extraction step of mixing water to be treated containing oil with a solvent, and extracting the oil into the solvent, and the solvent after the oil extraction is a crystal resonator. a predetermined amount trace amount supplied to the upper, front Stories and resonant frequency measuring step of measuring a plurality of times the resonance frequency of the crystal oscillator with a predetermined period, the resonance when the change amount of the plurality of times measured resonance frequency is less than a predetermined value And a step of measuring an oil content remaining on the crystal resonator after the solvent evaporates based on the frequency .

Further, the oil content measuring apparatus of the present invention includes a fluid device that mixes water to be treated containing oil with a solvent and extracts the oil into the solvent, and is connected to the fluid device, and the solvent after the oil extraction is used as a crystal resonator. a predetermined amount trace supply dispensing nozzle above, a sensor circuit for measuring the resonant frequency before Symbol crystal oscillator, a controller for controlling at least the fluid device and the sensor circuit, the predetermined amount from the dispensing nozzle Resonance frequency when the resonance frequency of the crystal unit to which a small amount of solvent after oil extraction is supplied is received from the sensor circuit a plurality of times at a predetermined cycle, and the amount of change in the resonance frequency received a plurality of times is equal to or less than a predetermined value And an arithmetic unit that measures oil remaining on the quartz resonator after the solvent evaporates.

  ADVANTAGE OF THE INVENTION According to this invention, the oil content measuring method and oil content measuring apparatus which can measure the oil content which remains in the to-be-processed water in water treatment field | areas, such as Oil & Gas, can be provided with high precision, for example.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a whole lineblock diagram of the oil content measuring device concerning one example of the present invention. It is a longitudinal cross-sectional view of the fluid device which comprises the oil content measuring apparatus shown in FIG. It is explanatory drawing of the principle by which the oil component in to-be-processed water osmose | permeates and is extracted in hexane. It is explanatory drawing of the operation | movement sequence of the fluid device shown in FIG. It is a schematic block diagram of the crystal oscillator shown in FIG. It is a functional block diagram of the sensor circuit and controller shown in FIG. It is explanatory drawing showing the state of the oil content measurement process after a solvent extraction process. It is a whole processing flow figure by the oil content measuring device concerning one example of the present invention. It is a flowchart of the repetition frequency determination in a solvent extraction process. It is a figure which shows the relationship between the repetition frequency in a solvent extraction process, and oil concentration. It is a figure which shows the time change of the resonant frequency measured by the oil content measuring apparatus shown in FIG. It is a figure which shows the time change of the resonant frequency measured by the oil content measuring apparatus which concerns on the other Example of this invention.

  The treated water in this specification includes accompanying water at the site of Oil & Gas, domestic wastewater, industrial wastewater, or the like, and the treated water is sometimes called sample water. In the following, the measured value by the QCM method is referred to as a resonance frequency, but the natural frequency has the same meaning.

  First, the oil content analysis of the water to be treated is defined by the official method (Water Pollution Control Law). In the analysis method, the substance extracted into n-hexane (hereinafter simply referred to as hexane) is the oil content in the water to be treated. Is defined. Therefore, in the official method, first, oil is extracted from the water to be treated into hexane as a solvent, and after evaporating the hexane, the oil concentration of the original water to be treated is measured from the mass of the substance remaining.

  A high-precision, high-sensitivity electronic balance, etc. is used to measure the mass, but when measuring the water to be treated at a diluted concentration, sufficient oil that can be detected by the electronic balance must be extracted into hexane. Both water to be treated and hexane require a large volume. Therefore, in order to evaporate a large volume of hexane in a shorter time, a high temperature / depressurized environment is required, and it is not suitable for a rapid in-situ analysis required at a water treatment site of Oil & Gas.

  Instruments that apply spectroscopic analysis have been put to practical use as an alternative to official methods, and handy-type devices that can be used outdoors have also been commercialized. However, sample pretreatment such as solid removal and solvent extraction must be performed in advance, and a calibration curve between concentration and absorbance must be created for each analyte using a control sample. There is.

  As described above, in the solvent extraction method / gravimetric method, spectroscopic measurement, and the like based on the official method, it has been impossible to analyze the oil component with sufficient accuracy at the water treatment site.

  In the method for measuring oil content in water to be treated according to an embodiment of the present invention, first, all oil content in water to be treated is transferred to hexane based on the official method (hexane extraction). Then, a small amount of the hexane is supplied onto the crystal resonator to evaporate only the hexane. Measure the mass of the substance (hexane extract material (oil)) that remains and adheres to the crystal unit after evaporation of hexane from the amount of change in the resonance frequency of the crystal unit. Then, the concentration of oil contained in the water to be treated is measured from the measured mass of the hexane extract substance, a small amount of hexane and the volume of the original water to be treated.

  Such a series of analysis processes, that is, extraction of oil into hexane, evaporation of hexane containing oil on a quartz crystal, and mass measurement of residual deposits on the crystal are realized with a simple device configuration. .

  A measurement method for determining the amount of adhesion (mass) on the surface of the crystal unit from the amount of change in the resonance frequency of the crystal unit is called the QCM method, and has been put to practical use for film thickness monitoring in the thin film formation process. Yes. The crystal resonator for QCM that has been put into practical use has, for example, a resonance frequency of 10 mm in diameter, several hundred μm in thickness, and several MHz band. The mass of the adhered substance on the surface can be measured in the range of several ng to several tens of μg.

  The method for measuring oil content in water to be treated according to an embodiment of the present invention can be applied to a water treatment plant as a residual oil content monitor for water / oil separation treatment processes such as coagulation magnetic separation, and also for monitoring the operation status and performance of the plant. Can be applied.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an overall configuration diagram of an oil content measuring apparatus according to an embodiment of the present invention. The oil content measuring apparatus 1 of the present invention extracts the oil content in the water to be treated into hexane as a solvent, and drives the piston in the syringe type fluid device 101 for feeding the extracted oil content and the syringe 101. The motor 102 evaporates the hexane from which the oil has been extracted, and further oscillates the crystal oscillator 103 for the QCM sensor and the crystal oscillator 103 for measuring the mass of the remaining hexane extract material (oil), and measures the resonance frequency. The sensor circuit 104 includes a display unit 109 that displays the measurement result, and includes a controller 105 that controls the entire oil content measuring apparatus 1.

  Although not shown, a power source for driving these devices is also provided. In particular, when used outdoors, such as Oil & Gas, a battery that can be repeatedly charged may be used.

  In the fluid device 101, water to be treated and hexane 110 as a solvent are sucked from the inflow pipe 106, and an internal piston is driven by the motor 102 to cause the hexane to extract oil in the water to be treated (details will be described later). Then, after the oil in the water to be treated is almost completely extracted into hexane, a small amount of the extracted hexane 111 containing the oil extracted from the dispensing nozzle 108 is supplied onto the crystal unit 103 via the outflow pipe 107. .

  Next, the internal structure, operation, and function of the fluidic device 101 will be described with reference to FIGS. 2 is a longitudinal sectional view of the fluid device 101 constituting the oil content measuring apparatus 1 shown in FIG. 1, and FIG. 3 is an explanatory diagram of the principle that the oil content in the water to be treated permeates and is extracted from hexane. 4 is an explanatory diagram of an operation sequence of the fluidic device 101. FIG.

  As shown in FIG. 2, the fluid device 101 includes a syringe 201 having a substantially cylindrical appearance, a piston 208 that moves up and down in the syringe 201, and a piston 208 that is connected to the piston 208 and moved up and down by a driving force from the motor 102. It is composed of a piston rod 211 that is linearly moved. In addition, the syringe 201 includes a partition unit 204 that divides the internal space of the syringe 201 into two chambers in the vertical direction along the longitudinal direction. As shown in FIG. 2, the upper surface of the partition portion 204 is formed of a cylindrical member having a conical depression, and is formed at a substantially central portion of the partition portion 204 and penetrates along the longitudinal direction of the syringe 201. A small-diameter nozzle 202 (hereinafter referred to as a small-diameter nozzle) that is a second through-hole that is formed around the communication hole 203 and that extends through the longitudinal direction of the syringe 201. Multiple) are arranged. The hole diameter of the communication hole 203 is larger than the hole diameter of the small-diameter nozzle 202, and the communication hole 203 is provided with a sphere 205 having a diameter large enough to close it. In this embodiment, a sphere is used to block the communication hole 203, but it may be a conical body. Further, it is the reverse of blocking the flow from the upper chamber to the lower chamber through the communication hole 203 with the partition 204 as a boundary. A member having a stop valve function may be arranged.

  Further, an inlet port 206 and an outlet port 207 that can be connected to the inflow pipe 106 and the outflow pipe 107 shown in FIG. 1 are formed on the upper surface of the syringe 201, respectively. The suction of hexane and treated water from the inflow port 206 through the inflow pipe 106 and the discharge of hexane after extraction from the outflow port 207 to the outflow pipe 107 are the downward movement of the piston 208 in the direction of the arrow 210 and the arrow 209. Realized by rising in the direction of A female screw (not shown) is formed at the center of the piston 208 and is connected via a screw thread (not shown) formed on the piston rod 211. Further, the piston rod 211 is coupled to the motor 102 shown in FIG. 1, and the piston rod 211 is rotated by rotating the motor 102, and the rotational displacement is converted into a linear displacement of the piston 208 ascending or descending.

  Although not shown, in order to convert such rotational displacement into linear displacement, a mechanism for restraining the rotational displacement is provided so that the piston 208 is not rotated with the rotation of the piston rod 211. If designed based on the normal screw standard, when the piston rod 211 rotates in the clockwise direction 212 in FIG. 2, the piston 208 descends in the direction of the arrow 210 and rotates in the counterclockwise direction 213. When it rises in the direction of arrow 209.

  Further, the adjustment of the upward force in the direction of the arrow 209 applied to the piston rod 211 is performed by adjusting the driving voltage, current, etc. of the motor 102 by the controller 105 shown in FIG. Is done.

  Next, how oil is extracted from the water to be treated into hexane in the fluid device 101 will be described. As a general characteristic of hexane as a solvent, oil dissolves but is not mixed with water because it is hydrophobic. When the oil content is measured in accordance with the official method described above, the water to be treated and hexane are put into a container and the oil on the water to be treated side is extracted into hexane while both are vibrated. At that time, the hexane 215 is dispersed as fine droplets in the water to be treated 214 as shown in FIG. In this dispersed state of hexane 215, the total area of the interface between the water to be treated 214 and hexane 215 is increased, and the oil component 216 on the water to be treated 216 is efficiently passed through the interface as shown by the arrow in FIG. Move to 215 side.

  This embodiment is characterized in that the water to be treated 214 and hexane 215 are not vibrated together with the container, but a dispersed state of hexane 215 as shown in FIG. 3 is formed by a fluid operation using a nozzle. As shown in FIG. 4, when a fluid passes through a narrow flow path such as the small diameter nozzle 202 at a high flow rate, a jet is generated at the outlet of the small diameter nozzle 202. Since strong shear stress is generated in the flow field inside the jet, one of the liquids of two phases (treated water 214 and hexane 215 in the present embodiment) repeats splitting near the outlet of the small diameter nozzle 202, and Breaks up into fine droplets. Utilizing such characteristics of the two-phase fluid, a state in which fine hexane 215 droplets are dispersed in the water to be treated 214 is generated, and the extraction of the oil in the water to be treated 214 into the hexane 215 phase is promoted. It was.

  As shown in the left diagram of FIG. 4, when the piston 208 is in a stopped state, the hexane 215 and the treated water 214 are separated. This is because the hexane 215 has a lower density than the water to be treated 214, so that the hexane 215 is always on the upper side in the separated state. When the piston 208 is rapidly lowered as shown in the central view of FIG. 4, the sphere 205 closes the communication hole 203, and the flow path communicating from the upper chamber to the lower chamber with the partition portion 204 as a boundary is only a plurality of small diameter nozzles 202. It becomes. At this time, if the piston 208 is lowered at a sufficient speed, a jet is formed in the vicinity of the outlet of each small-diameter nozzle 202, and the phase of the water 214 to be treated is passed when the hexane 215 phase passes through the small-diameter nozzle 202. Disperse as fine droplets. Thus, by dispersing the phase of hexane 215 in the phase of water to be treated 214, the total area of the interface between the two can be increased, and the extraction of oil with hexane proceeds.

  Next, in this dispersed state, when the piston 208 is slowly raised at a speed at which the sphere 205 slightly floats as shown in the right diagram of FIG. 4, the liquid containing hexane from which the dispersed state or oil has been extracted is placed in the upper chamber. Then, a flow indicated by an arrow 217 is formed, and the hexane 215 droplet and the water to be treated 214 are mixed and moved to the upper chamber. By this mixing, the oil concentration near the interface of hexane is made uniform, and the movement of oil to hexane is further promoted.

  In the extraction process of oil to hexane (hereinafter referred to as a solvent extraction process) corresponding to the pretreatment of the water to be treated 214 in the oil content measuring apparatus 1 of the present embodiment, the piston 208 is shown in the center and right diagrams of FIG. 218 and 209 are repeatedly executed 218. Thereby, the area increase of the interface between the to-be-processed water 214 and hexane 215 and mixing of both phases are performed, and it can extract, without vibrating the whole container. This increase in the total area of the interface and mixing of the dispersion are repeated until the oil has almost completely moved to the hexane 215 side.

  When the oil component 216 in the water to be treated 214 is almost completely extracted to the hexane 215 phase, the piston 208 is once stopped, and is left still as shown in the left diagram of FIG. . Thereafter, the inlet 206 is closed with a control valve or a pinch valve (not shown), and the outlet 208 and the outlet pipe 107 shown in FIG. Then, a minute amount of hexane 215 after oil extraction is supplied from the dispensing nozzle 108 onto the quartz crystal vibrator 103.

  Next, the oil measurement process after the solvent extraction process will be described. FIG. 5 shows a schematic configuration of the crystal unit 103 shown in FIG. The QCM method uses electro-mechanical vibration in the thickness-slip direction of the crystal unit 103 (Thickness-shear-mode resonator), so that both sides of the crystal plate cut in an orientation called AT cut are used. A front surface electrode 301 (side facing the dispensing nozzle 108) and a back surface electrode 302 (side opposite to the front surface electrode 301 with the crystal plate interposed therebetween) are provided. In the left diagram of FIG. 5, the back electrode 302 is indicated by a broken line because it is on the back side of the crystal unit 103. An oscillation circuit is configured with such a crystal resonator 103 as a part of an electric vibration element, and the resonance frequency when the oscillation circuit is oscillated is measured. For example, gold (Au), platinum (Pt), Cr, or the like may be used as a constituent material of the front electrode 301 and the back electrode 302.

  As shown in the right diagram of FIG. 5, when the deposit 303 is present on the electrode surface (surface electrode 301) on one side, the resonance frequency changes because the vibration characteristics in the thickness-slip direction change (according to the mass of the deposit). The resonance frequency shifts in the lower direction). The mass of the deposit on the electrode surface is measured from the amount of decrease in the resonance frequency at this time. The relationship between the amount of change in the resonance frequency and the mass is given by the Sauerbey equation (the following equation (1)) with the shape of the crystal resonator 103, the area of the electrode, etc. as parameters.

Δf = −2 × f ₀ ² × {Δm / (A × (ρq × μq) ^1/2 )} (1)
Here, Δf is a resonance frequency change amount (Hz), Δm is a mass change amount (g), f ₀ is a basic resonance frequency (Hz), ρq is a crystal density (g / cm ³ ), and μq is an AT-cut crystal. Shear stress (g / cm.s ² ), A is electrode area (cm ² ), ρq = 2.648 g / cm ³ , μq = 2.947 × 10 ¹¹ g / cm ^{2 s 2}
In this embodiment, such a quartz crystal vibrator 103 for QCM is used as a mass sensor for measuring the mass of oil in the water to be treated.

  FIG. 7 shows the state of the oil content measurement step after the solvent extraction step. As shown in FIG. 7, the hexane after the solvent extraction step corresponding to the pretreatment described in FIG. 4, that is, the hexane from which oil in the water to be treated has been extracted is dispensed from the fluid device 101 via the outflow pipe 107. A small amount of hexane 111 extracted from 108 is supplied to the substantially central portion of the surface electrode 301 of the quartz crystal vibrator 103 at a microliter level volume. The supply amount per time is preferably 0.001 μL to 0.1 μL. Since hexane is also highly hydrophilic like other organic solvents, the droplets wet and spread on the surface electrode 301, and the droplets 305 after wetting and spreading evaporate in about several seconds to several tens of seconds. After the hexane is completely evaporated, only the oil component 306 extracted into the hexane adheres to the surface electrode 301 and remains. The adhering residue (oil content 306), that is, the mass (m) of the hexane extraction substance (oil content 306) defined as the oil content in the official method, and the volume of hexane after the oil content extraction supplied from the dispensing nozzle 108 (V1) ), The oil concentration in hexane after oil extraction is obtained. In addition, the oil concentration in the water to be treated is obtained based on the volume (V2) of the water to be treated when the oil is extracted into the hexane in the solvent extraction step and the mass (m) of the hexane extract material (oil 306). Can do.

  For example, when the water to be treated is associated water in Oil & Gas, the oil concentration in the associated water may be extremely low. In such a case, only a very small amount of oil is extracted into hexane in the solvent extraction step, and a sufficient amount of residual deposits cannot be obtained by supplying a small amount of hexane once after extracting oil of several μL level. There is. In such a case, as shown in FIG. 7, a minute amount is supplied to the same position on the surface electrode 301 a plurality of times, and the minute amount supply and evaporation are repeated until the mass that can be detected by the QCM is reached.

Here, the configuration of the sensor circuit 104 and the controller 105 shown in FIG. 1 will be described. FIG. 6 shows functional blocks of the sensor circuit 104 and the controller 105. Sensor circuit 104, a crystal oscillation after the oscillation circuit 104c, hexane trace supply oil in the for-treatment water is extracted at a substantially central portion on the surface electrodes 301 for vibrating the crystal resonator 103 at the fundamental resonant frequency f ₀ A frequency measurement unit 104a and a storage unit 104b that measure the resonance frequency of the child 103 at a predetermined period are provided. The controller 105 reads out and executes various programs stored in the storage unit 105b in advance, adjusts the driving voltage and current of the motor 102 shown in FIG. 1 and controls the torque generated on the rotating shaft of the motor 102. The control part 105c and the calculation part 105a are comprised from the display control part 105d for displaying the calculation result, ie, the oil content density | concentration in the to-be-processed water mentioned above, on the display part 109. FIG. Note that the arithmetic unit 105a and the control unit 105c may be realized integrally. In addition to the control of the motor 102, the control unit 105c controls the operation timing of the oscillation circuit 104c in the sensor circuit 104, and the timing of supplying a small amount of hexane after oil extraction to the surface electrode 301 by the dispensing nozzle 108. Control is also performed.

An overall processing flow of the oil content measuring apparatus 1 executed by the sensor circuit 104 and the controller 105 is shown in FIG. After the solvent extraction step (step S1) in which the fluid device 101 described in FIGS. 2 to 4 is operated to move and extract the oil in the water to be treated to hexane as the solvent, hexane as the solvent after oil extraction Is supplied to the substantially central portion on the surface electrode 301 from the dispensing nozzle 108 (first time) (step S2). At this time, the control unit 105c of the controller 105 adjusts the driving voltage of the motor 102 and the like so that the amount of hexane after oil extraction supplied in a minute amount from the dispensing nozzle 108 becomes a predetermined amount (for example, several μL). The inner piston 208 is slowly raised. The operation begins before the step S2, the crystal oscillator 103 to the resonant state by 104c in the outgoing circuit in advance sensor circuit 104, the resonant frequency when the fundamental resonance frequency _{f 0,} the storage unit 104b and the storage unit 105b To store.

  Next, in step S2, the resonance frequency of the crystal unit 103 in a state where a small amount of hexane is supplied onto the surface electrode 301 is measured at a predetermined cycle by the frequency measurement unit 104a in the sensor circuit 104 (step S2). S3). Thereby, the fluctuation | variation of the resonant frequency of the crystal oscillator 103 which changes with time (every measurement period) is obtained. The fluctuation of the resonance frequency is caused by evaporation of hexane which is the solvent described in FIG.

  The storage unit 104b in the sensor circuit 104 stores a resonance frequency fluctuation threshold value (Th) in advance, and a resonance frequency fluctuation that is a difference between the current resonance frequency measured in step S3 and the previous value. The frequency measurement unit 104a determines whether it is equal to or less than a predetermined value (threshold value Th) (step S4). When the fluctuation of the resonance frequency is larger than the predetermined value (threshold value Th) in step S4, the process returns to step S3 and the resonance frequency in the next cycle is measured. On the other hand, as a result of the determination in step S4, when it is determined that the resonance frequency fluctuation is equal to or less than the predetermined value, the process proceeds to step S5. Here, the threshold Th may be set as appropriate, for example, 1 Hz. In addition, the comparison with the predetermined value of the resonance frequency fluctuation in this step S4 is, as explained in FIG. 7, after the hexane is completely evaporated from the hexane after oil extraction on the surface electrode 301, It is noted that since only the oil component is attached to, the fluctuation of the resonance frequency measured in each period thereafter is almost eliminated except for the fluctuation due to the disturbance.

  In step S5, the resonance frequency determined to be equal to or less than the predetermined value in step S4 is stored in the storage unit 104b in the sensor circuit 104. At this time, the resonance frequency stored in the storage unit 104 b is transmitted to the controller 105 and stored in the storage unit 105 b in the controller 105.

Subsequently, it is determined whether or not the next measurement should be performed (step S6). It determines whether to the next measurement, at step S5, is carried out by comparing the fundamental resonance frequency f ₀ which has previously been stored and the resonance frequency stored in the storage unit 105b of the controller 105. That is, as described above, the concentration of oil in the water to be treated such as associated water may be extremely low, and even if the hexane after the first minute supply is completely evaporated, a sufficient amount of residual deposits cannot be obtained. This is because cases may arise.

  If it is determined in step S6 that the next measurement is present, the process proceeds to step S7, and a small amount of hexane after oil extraction is supplied from the dispensing nozzle 108 to the surface electrode 301 (second time). Then, the process returns to step S3, and the subsequent steps are repeatedly executed.

  If it is determined in step S6 that there is no next measurement, the process proceeds to step S8. In step S8, the calculation part 105a in the controller 105 calculates | requires the mass (m) of the oil component which is a residual deposit on the surface electrode 301 based on said Formula (1). In step S1, the concentration of oil in the water to be treated is obtained from the volume (V2) of the water to be treated when the oil is extracted into hexane and the mass (m) of the obtained oil. That is, the determined mass (m) of oil is converted to the oil concentration in the water to be treated (step S8). The oil concentration in the for-treatment water obtained in step S8 is stored in the storage unit 105b (step S9), and the process is terminated.

  In this embodiment, the resonance frequency determined to be equal to or lower than the predetermined value in step S4 is stored in the storage unit 104b and the storage unit 105c. However, the present invention is not limited to this, and is measured at a predetermined cycle in step S3. The resonance frequency may be stored in the storage unit 104b and the storage unit 105b each time. In this case, it is possible to display the relationship between the measured resonance frequency and the measurement time on the display unit 109 by the display control unit 105b. Moreover, you may comprise so that the determination by step S4 may be performed by the calculating part 105a instead of the frequency measurement part 104a.

Next, determination of the number of repeated operations in the solvent extraction step (step S1) in FIG. 8 will be described. FIG. 9 shows a flow for determining the number of repetitions in the solvent extraction step. In step S10, the repetition number M of solvent extraction by the fluidic device 101 described in FIG. 4 is set to an initial value N ₀ (natural number). Incidentally, it illustrates a case where the initial value N ₀ in FIG. 10 described later was 10 times. Here, the number of repetitions of solvent extraction is 1 including the step of rapidly lowering the piston 208 shown in the center diagram of FIG. 4 and the step of slowly raising the piston 208 shown in the right diagram of FIG. Means the number of combinations of lowering and slow raising of the piston 208. The initial value N ₀ set in step S 10 is stored in the storage unit 105 b in the controller 105.

The control unit 105c reads the number of repetitions M (in this case, the initial value N ₀ ) stored in the storage unit 105b, adjusts the driving voltage of the motor 102, and controls the lowering and slowing up of the piston 208. That is, the repetitive operation in the solvent extraction step is executed M times (here, N ₀ times) (step S11).

The control unit 105c controls to supply a small amount (first time) of hexane, from which oil has been extracted into the solvent after the solvent extraction step M has been performed, to the surface electrode 301 from the dispensing nozzle 108 (step S12). The amount of hexane droplets after extraction of a small amount of oil to be supplied is several μL, and this value is stored in the storage unit 105 b of the controller 105 in advance. Further, before supplying a small amount of hexane after oil extraction, the control unit 105c controls the transmission circuit 104c in the sensor circuit 104 to bring the crystal unit 103 into a resonance state, and the resonance frequency at that time is the basic resonance frequency f _0. And stored in the storage unit 104b and the storage unit 105b.

  Next, after oil-extracted hexane adheres to the surface electrode 301, the frequency measurement unit 104a in the sensor circuit 104 starts frequency measurement at a predetermined cycle (step S13). The resonance frequency measured every predetermined period is stored in the storage unit 104b and the storage unit 105b (step S14). Although omitted in FIG. 9, the threshold value (Th) of the resonance frequency fluctuation is stored in advance in the processing similar to step S4 in FIG. 8, that is, the storage unit 104b in the sensor circuit 104. The frequency measurement unit 104a determines whether the resonance frequency fluctuation, which is the difference between the current resonance frequency measured in step S3 and the previous value, is equal to or less than a predetermined value (threshold value Th). When the resonance frequency fluctuation is equal to or smaller than the predetermined value (threshold value Th), the process proceeds to step S15.

  In step S15, as in step S8 described with reference to FIG. 8, the calculation unit 105a in the controller 105 obtains the mass (m) of oil that is a residual deposit on the surface electrode 301 based on the above equation (1). In step S11, the concentration of oil in the water to be treated is obtained from the volume (V2) of the water to be treated when the oil is extracted into hexane and the mass (m) of the obtained oil. That is, the determined mass (m) of oil is converted into the oil concentration in the water to be treated.

The previous oil concentration is compared with the oil concentration converted in step S15, and the calculation unit 105a in the controller 105 determines whether the oil concentration has converged (step S16). In the case of the determination result that it has converged, M times are stored as the number of repeated operations in the storage unit 105b in the controller 105 (step S18), and the process ends. Further, in the case of the determination result that it has not converged (the previous value does not exist at the initial value N ₀ setting stage, the process proceeds to step S17), the process proceeds to step S17, and the number of times the fluid device 101 repeats the solvent extraction. M is added to the current M and N (natural number) is added, and the above-described steps S11 to S16 are similarly executed. At this time, the oil component that is a residual deposit adhering to the surface electrode 301 is washed, and Steps S12 to S16 are executed. Note that the number M of repetitions after the N addition is stored in the storage unit 105 b in the controller 105. The initial value N ₀ and the number of additions N may be set as appropriate by the user. In the example shown in FIG. 10 described later, the case where both the initial value N ₀ and the number of additions N are 10 is illustrated.

  The convergence determination by the calculation unit 105a in step S15 can be realized by setting a predetermined threshold value and storing it in the storage unit 105b, for example, as in the case of determination of resonance frequency fluctuation.

FIG. 10 shows the relationship between the number of repetitions in the solvent extraction step and the oil concentration. In the detailed flow of the solvent extraction process described with reference to FIG. 9, in FIG. 10, the initial value N ₀ set to the number of repetitions M in step S10 of FIG. 9 is added to 10, and further added to the current number of repetitions M in step S17. The case where the number N of additions to be performed is set to 10 is shown.

As shown in FIG. 10, the initial values N ₀ to 10, by executing the step S15 from the step S11 shown in FIG. 9 described above, Motomari is the oil content in the repeating 10 times, during the oil concentration graph Dots are displayed at the corresponding positions. At this stage, since it is an initial value, in the determination in step S16 shown in FIG. 9, the previous value does not exist and the process proceeds to step S17. The number of additions is 10 times the current number of repetitions 10 (M). (N) is added, and in step S11, the operation is further repeated 10 times. Then, after washing the oil component that is a residual deposit adhering to the surface electrode 301, the oil concentration at the number of repetitions of 20 is obtained by executing steps S12 to S15, and the oil concentration at the position corresponding to the oil concentration in the graph is obtained. Dots are displayed.

  Next, in step S16 of FIG. 9, the oil concentration at the number of repetitions of 10 is compared with the oil concentration at the number of repetitions of 20, and the convergence determination is executed. As described above, in the convergence determination, the predetermined threshold value stored in advance in the storage unit 105b is compared with the difference between the two oil component concentrations, and in the example illustrated in FIG. The number of additions 10 (N) is added to the current number of repetitions 20 (M), and the same processing is executed. FIG. 10 shows a state in which the oil concentration when the repetition is performed up to 60 times is displayed in dots.

  As shown in FIG. 10, the oil concentration at the number of repetitions of 40, 50, and 60 converges to a true value. As the number of repetitions increases from FIG. 10, the oil content in the water to be treated moves to hexane, which is a solvent, and after repeating a certain number of times, the oil content in the water to be treated is completely extracted by moving to hexane, which is a solvent. Therefore, the oil concentration measured after that becomes the same value (true value).

  As described with reference to FIGS. 9 and 10, by obtaining the number of repetitions (M) in the solvent extraction step in advance, even if the water to be treated has a different property, the oil concentration in the water to be treated is highly accurate. It becomes possible to measure. This is because the number of repetitions until the oil in the water to be treated is completely extracted into the solvent depends on the properties of the water to be treated.

  As described above, since the flows shown in FIGS. 8 and 9 are executed under the control of the controller 105, the oil content measuring apparatus 1 can be automated.

  In the development of an oil / water separation treatment plant or the like, if the number of repetitions in the solvent extraction process described in FIG. 9 is obtained in advance, the fluctuation of the oil concentration in the treated water can be detected quickly at the plant development site. Is possible.

  FIG. 11 shows a temporal change in the resonance frequency measured by the oil content measuring apparatus 1 shown in FIG. In FIG. 11, the horizontal axis represents time, the vertical axis represents the resonance frequency measured by the frequency measuring unit 104 a in the sensor circuit 104, and hexane, which is a solvent after oil extraction, is dispensed from the dispensing probe 108 to the surface of the crystal unit 103. The case where it dripped 3 times to the same position of the approximate center part of the electrode 301 is shown.

  In the present embodiment, as described above, the number of repetitions (M) in the solvent extraction process obtained by the flow shown in FIG. 9 is stored in the storage unit 105b in the controller 105, and the solvent extraction process is executed. (Especially, the resonance frequency after the oil is extracted by the solvent extraction step by the calculation unit 105a) is measured.

As shown in FIG. 11, the resonance frequency measured immediately after the first minute supply shows a low value, and then the resonance frequency measured at a predetermined period is the evaporation of hexane adhering to the surface electrode 301 with time. As the hexane is completely evaporated, the measured resonance frequency converges to a substantially constant value. The difference between the fundamental resonant frequency f ₀ of the crystal oscillator 103 in this case is .DELTA.f1 (amount of change in the resonant frequency). Subsequently, when the same amount as the first time is supplied in a small amount (second time) to the same position on the surface electrode 301 and the resonance frequency is measured similarly, the resonance frequency after convergence to a substantially constant value and the basic resonance frequency f _0. the difference between the .DELTA.f2, further, in the resonance frequency measured after trace supply third time, the difference between the fundamental resonant frequency f ₀ becomes .DELTA.f3.

As shown in FIG. 11, when the minute supply amount for each time is constant, the number of times of supply and the change amounts Δf1, Δf2, and Δf3 of the resonance frequency for each supply show a linear relationship, and the basic resonance frequency f _The amount of change with respect to ₀ is a sufficient difference, and the oil concentration in the water to be treated can be determined with higher accuracy.

  Moreover, you may comprise so that the oil content density | concentration in to-be-processed water may be calculated | required by guide | inducing the relationship of the variation | change_quantity of the said resonant frequency by the least squares method.

  According to the present embodiment, it is possible to measure the oil remaining in the water to be treated at the water treatment site with high accuracy.

  In addition, according to this example, the oil content in the water to be treated can be effectively transferred to hexane as a solvent, and the hexane after subsequent oil extraction is measured for oil concentration by the QCM method. Even when the oil concentration is low, it is possible to measure.

  In addition, it is possible to automate the measurement of oil concentration, and it is also possible for a developer to perform oil concentration measurement on the Oil & Gas water treatment site without requesting an inspection engineer in the laboratory as in the past. Moreover, since vibration is not used in the extraction of oil into hexane, there is a feature that a failure due to vibration can be avoided.

  FIG. 12 shows a temporal change in the resonance frequency measured by the oil content measuring apparatus according to another embodiment of the present invention. In Example 1, the concentration of oil in the water to be treated was obtained based on the resonance frequency measured every time a small amount of hexane was supplied after oil extraction, whereas the resonance frequency measured every time a small amount of hexane was supplied The difference is that the oil concentration in the water to be treated is obtained by averaging. Since other points are the same as those of the first embodiment, description thereof is omitted.

FIG The hexane feed after the first round of oil extraction as shown in 12, no significant difference is obtained in the difference between the resonant frequency and the fundamental resonant frequency f ₀ to be measured. FIG. 12 shows a temporal change in the resonance frequency of the crystal resonator 103 measured for each hexane supply after oil extraction a plurality of times. This can occur when measuring the water to be treated with a thin oil content, and the amount of trace amount of hexane after one oil extraction is increased as compared with Example 1. Therefore, it takes time for hexane dropped on the surface electrode 301 of the crystal unit 103 to evaporate, and while the electrode is covered with hexane, that is, during a period in which hexane is not evaporated, a predetermined cycle is required. No change appears in the resonance frequency measured at, and the time change of the resonance frequency measured becomes intermittent as shown in FIG.

In such a case, the temporal change in the intermittent resonance frequency from a plurality of times of supply is stored in the storage unit 105 b in the controller 105. Then, the calculating section 105a in the controller 105, and grouped by unrecognized fragment data a significant difference, with an average value of the resonance frequencies in the group, the average value and the fundamental resonant frequency f ₀ obtained The difference ΔF1 (average change in resonance frequency) and ΔF2 are obtained and stored in the storage unit 105b. The computing unit 105a obtains the oil concentration in the water to be treated from the total supply amount (volume) for each group and the average change amounts ΔF1 and ΔF2 of the resonance frequency, as in the first embodiment.

  According to the present embodiment, in addition to the effects of the first embodiment, even when the water to be treated is thin, the oil remaining in the water to be treated can be measured with high accuracy.

  As mentioned above, according to the oil content measuring apparatus 1 which concerns on Example 1 and Example 2, oil content is contained in to-be-processed water by repeating operation of dispensing (a trace amount supply), evaporation, and mass measurement of a residual deposit. As long as the oil concentration is as low as possible, it can be measured in principle. However, in order to accurately measure the oil concentration in a shorter time, there is an optimal one-time dispensing amount, and the conditions differ depending on the operating environment of the oil content measuring apparatus 1 that affects the evaporation of hexane.

  Conversely, when measuring water to be treated having a high oil concentration, for example, the minimum amount that can supply a small amount of hexane after the solvent extraction step by the fluid device 101 onto the surface electrode 301 of the crystal unit 103 by the dispensing nozzle 108. It is assumed that an oil amount of several hundred μg already remains on the surface electrode 301 of the crystal unit 103 at the injection amount (0.1 μL level). In this case, the operation range of the resonance frequency of the crystal unit 103 may be exceeded, and it may be difficult to measure the oil concentration by the oil content measuring device 1. In such a case, before introducing the water to be treated into the oil content measuring apparatus 1, the water to be treated is appropriately diluted in advance, and after determining the oil concentration in the water to be treated after dilution, the dilution factor is used. What is necessary is just to correct | amend the calculated | required oil concentration.

  In the description of Example 1 and Example 2 above, hexane was used as the oil extraction solvent employed in the official method of Japan (Water Pollution Prevention Law), but not limited thereto, for example, acetone, dichloromethane, etc. Any solvent can be used as long as similar functions and effects can be obtained.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace the configurations of other embodiments with respect to a part of the configurations of the embodiments.

DESCRIPTION OF SYMBOLS 1 ... Oil content measuring apparatus, 101 ... Fluid device, 102 ... Motor, 103 ... Crystal oscillator, 104 ... Sensor circuit, 104a ... Frequency measuring part, 104b ... Memory | storage part 104c ... Oscillator circuit 105 ... Controller 105a ... Calculation unit 105b ... Storage unit 105c ... Control unit 105d ... Display control unit 106 ... Inflow pipe 107 ... Outflow pipe, 108 ... Dispensing nozzle, 109 ... Display, 111 ... Hexane after extraction, 201 ... Syringe, 202 ... Small diameter nozzle, 203 ... Communication hole , 204 ... partition part, 205 ... sphere, 206 ... inlet, 207 ... outlet, 208 ... piston, 211 ... piston rod, 214 ... treated water, 215 ... Hexa , 216 ... treatment water in oil, 301 ... surface electrode, 302 ... back electrode, 303 ... deposits, 306 ... oil after solvent evaporation

Claims (15)

A solvent extraction step of mixing water to be treated containing oil with a solvent, and extracting the oil into the solvent;
The resonance frequency measurement step of measuring a plurality of times in said solvent after oil extraction predetermined amount trace amount supplied onto the quartz oscillator to a predetermined period the resonance frequency before Symbol crystal oscillator,
Measuring the oil remaining on the crystal unit after the solvent has evaporated, based on the resonance frequency when the amount of change in the resonance frequency measured a plurality of times is equal to or less than a predetermined value. A characteristic oil content measuring method. The oil content measuring method according to claim 1,
The solvent extraction step uses a syringe having a partition portion having a plurality of through holes therein, and two spaces are formed in the longitudinal direction by the partition portion, and water to be treated containing the oil in the syringe; An oil content measuring method, wherein a solvent is caused to flow up and down through the plurality of through holes, and the oil content is extracted into the solvent. In the oil content measuring method according to claim 2,
An oil content measuring method, wherein the water to be treated and the solvent containing the oil content are passed through the plurality of through holes up and down a predetermined number of times. In the oil content measuring method according to claim 3,
The solvent from which the oil has been extracted and the water to be treated are separated by allowing the oil to be extracted by passing the through-hole up and down a predetermined number of times,
A method for measuring an oil content, wherein a predetermined amount of a solvent from which the oil content after the separation is extracted is supplied onto the crystal resonator. In the oil content measuring method according to claim 4,
Among the resonance frequencies measured at the resonance frequency measurement step, the resonance frequency when the difference from the previous value is equal to or less than a predetermined value, and a small amount of the solvent after oil extraction is supplied. An oil content measuring method characterized in that a difference from the fundamental resonance frequency of the crystal resonator to be measured is a change amount of the resonance frequency, and a mass of the oil content is obtained based on the change amount. In the oil content measuring method according to claim 5,
An oil content measuring method, wherein the oil concentration in the water to be treated containing the oil content is obtained based on the mass of the oil content obtained and the volume of the water to be treated containing the oil content in the solvent extraction step. A fluid device for mixing water to be treated containing oil with a solvent, and extracting the oil into the solvent;
A dispensing nozzle connected to the fluidic device for supplying a predetermined amount of the solvent after the oil extraction onto the crystal unit;
And a sensor circuit for measuring the resonance frequency of the previous Symbol crystal oscillator,
A controller for controlling at least the fluidic device and the sensor circuit;
The resonance frequency of the crystal resonator to which a small amount of the solvent after extraction of the predetermined amount of oil is supplied from the dispensing nozzle is received a plurality of times from the sensor circuit at a predetermined cycle, and the amount of change in the resonance frequency received a plurality of times. An oil content measuring apparatus comprising: an arithmetic unit that measures oil content remaining on the crystal resonator after the solvent evaporates based on a resonance frequency when is less than or equal to a predetermined value . In the oil content measuring device according to claim 7,
The fluidic device is:
A substantially cylindrical syringe having a partition part having a plurality of through-holes and having two spaces formed in the longitudinal direction by the partition part;
A piston inside the syringe and disposed below the partition and movable up and down in the syringe, and
An oil content measuring apparatus characterized by causing the water to be treated and the solvent containing the oil content in the syringe to flow up and down through the plurality of through holes and extracting the oil content into the solvent by the vertical movement of the piston. . In the oil content measuring apparatus according to claim 8,
The partition portion has a columnar shape, and is formed around a first through hole penetrating along the longitudinal direction of the syringe at a substantially central portion in a cross section, and is formed around the first through hole in the longitudinal direction of the syringe. A plurality of second through holes penetrating along,
The oil content measuring apparatus, wherein a hole diameter of the first through hole is larger than a hole diameter of the second through hole. In the oil content measuring apparatus according to claim 9,
The controller moves the piston up and down a predetermined number of times, and causes the water to be treated and the solvent containing the oil to flow up and down at least one of the first through hole and the second through hole. Oil content measuring device characterized by. In the oil content measuring device according to claim 10,
The controller is
By stopping the vertical movement of the piston, the solvent from which the oil has been extracted and the water to be treated are separated,
An oil content measuring apparatus, wherein a small amount of a solvent from which the oil content after separation is extracted is supplied to the crystal resonator through the dispensing nozzle by slowly raising the piston. In the oil content measuring device according to claim 7,
The calculation unit is supplied with a small amount of the resonance frequency when the difference from the previous value is equal to or less than a predetermined value among the resonance frequencies received from the sensor circuit and the solvent after oil extraction. The oil content measuring apparatus is characterized in that a difference from the fundamental resonance frequency of the crystal resonator measured before measurement is used as a change amount of the resonance frequency, and a mass of the oil content is obtained based on the change amount. In the oil content measuring device according to claim 12,
The computing unit calculates the oil concentration in the water to be treated containing the oil based on the mass of the oil to be obtained and the volume of the water to be treated containing the oil when the oil is extracted into the solvent by the fluid device. An oil content measuring device characterized by being obtained. In the oil content measuring apparatus according to claim 9,
The surface of the partition portion opposite to the surface facing the piston has a substantially conical recess.
A sphere having a diameter larger than the diameter of the first through hole is arranged above the surface of the partition portion having the substantially conical depression,
The oil content measuring apparatus, wherein the spherical body closes the first through-hole when the piston is lowered by the controller. In the oil content measuring apparatus according to claim 9,
The oil content measuring apparatus, wherein the solvent is dispersed into fine droplets in the syringe by flowing up and down through the second through hole.

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