JP2014130055A - Device and method for measuring iron concentration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the concentration of total iron existing in water, soluble iron, and suspended form iron without using a reagent.SOLUTION: An iron concentration measurement device 1 comprises: an absorbance measurement unit 7 for irradiating a sample water with light having a wavelength of 360-380 nm to measure absorbance; a concentration calculation unit 3 for calculating the iron concentration on the basis of an absorbance measured by the absorbance measurement unit 7; and a filter unit 6 for filtering a suspended form component from the sample water. The concentration calculation unit 3 calculates the concentration of total iron from an absorbance measured by the absorbance measurement unit 7 in the sample water before filtration by the filter unit 6, calculates the concentration of soluble iron from an absorbance measured by the absorbance measurement unit 7 in the sample water after filtration by the filter unit 6 and subtracts the concentration of the soluble iron from the concentration of the total iron to calculate the concentration of the suspended form iron.

Description

  The present invention relates to an iron concentration measuring apparatus and method.

Conventionally, an apparatus for optically determining the presence or absence of iron in water is known (see, for example, Patent Document 1).
This apparatus supplies the sampled water with a first agent that reduces trivalent iron ions to divalent iron ions and a second agent that develops color by reacting with divalent iron ions, and the transmittance of the irradiated light. The presence or absence of iron is determined by determining the presence or absence of a coloring substance.

JP 2006-284209 A

However, since the apparatus of Patent Document 1 is an apparatus that determines the presence or absence of iron by detecting divalent iron ions, it has the following disadvantages.
First, in water, iron is dissolved as soluble iron such as divalent iron ions and trivalent iron ions, and also exists as suspended iron such as hydroxides. There is an inconvenience that the concentration of suspended iron present in water cannot be measured with high accuracy simply by developing and detecting divalent iron ions.
Second, the device of Patent Document 1 mixes a reagent into sampled water, reduces trivalent iron ions to divalent iron ions by the first agent, and then adds the divalent iron ions and the second agent. Since the presence or absence of iron can only be determined after the color has been developed by this reaction, there is the inconvenience that the determination takes time.

  The present invention has been made in view of the above-described circumstances, and is capable of accurately measuring the concentrations of total iron, soluble iron, and suspended iron existing in water without using a reagent. It is an object of the present invention to provide a concentration measuring apparatus and method.

In order to achieve the above object, the present invention provides the following means.
One aspect of the present invention is an absorbance measurement unit that measures absorbance by irradiating sample water with light having a wavelength of 360 nm to 380 nm, and a concentration calculation unit that calculates iron concentration based on the absorbance measured by the absorbance measurement unit. And a filter unit that filters suspended components from the sample water, and the concentration calculation unit is configured to measure the concentration of total iron from the absorbance measured by the absorbance measurement unit for the sample water before filtration by the filter unit. Calculate the concentration of soluble iron from the absorbance measured by the absorbance measurement unit for the sample water after filtration by the filter unit, and subtract the concentration of soluble iron from the concentration of total iron to suspend An iron concentration measuring device for calculating the concentration of state iron is provided.

  According to this aspect, in the absorbance measurement unit, the sample water before filtration is irradiated with light having a wavelength near 370 nm, the absorbance is measured, and the iron concentration is calculated by the concentration calculation unit based on the measured absorbance. Thus, the total total iron concentration of soluble iron and suspended iron present in water can be measured. On the other hand, in the absorbance measurement unit, the sample water after filtration is irradiated with light having a wavelength near 370 nm, the absorbance is measured, and the concentration calculation unit calculates the iron concentration based on the measured absorbance. The concentration of soluble iron present in can be measured. And in a density | concentration calculation part, the density | concentration of suspended iron can be measured by subtracting the density | concentration of soluble iron from the total iron density | concentration. That is, according to this aspect, the concentrations of total iron, soluble iron, and suspended iron existing in water can be accurately measured without using a reagent.

  In the above aspect, the filter unit includes a plurality of filters having different pore diameters, and the concentration calculation unit calculates soluble iron from the absorbance measured by the absorbance measurement unit for the sample water that has passed through each filter. The concentration may be calculated, and the concentration of suspended iron for each particle size may be calculated by subtracting the concentration of each soluble iron from the total iron content.

  In another aspect of the present invention, the sample water is irradiated with light having a wavelength of 360 nm to 380 nm to measure the absorbance, and the sample water that has passed through the first absorbance measurement unit is used. A filter unit for filtering suspended components, a second absorbance measurement unit for measuring absorbance by irradiating light having a wavelength of 360 nm to 380 nm to the filtered sample water that has passed through the filter unit, and the second absorbance measurement unit Based on the absorbance of the sample water after filtration measured by the absorbance measurement unit, the concentration of soluble iron is calculated, and the absorbance of the sample water after filtration measured by the first absorbance measurement unit and the second Provided is an iron concentration measuring device including a concentration calculating unit for calculating the concentration of suspended iron based on the absorbance of sample water before filtration measured by an absorbance measuring unit.

  According to this aspect, while passing through the first absorbance measurement unit, the filter unit, and the second absorbance measurement unit, the absorbance of the sample water before filtration and the absorbance after filtration are measured, and the concentration calculation unit analyzes the solubility. The concentration of iron and suspended iron can be calculated.

  In another aspect of the present invention, the first step of measuring the absorbance by irradiating the sample water with light having a wavelength of 360 nm to 380 nm, and the step of filtering the suspended component by passing the sample water through a filter. 2, a third step of measuring the absorbance by irradiating the sample water filtered in the second step with light having a wavelength of 360 nm to 380 nm, the absorbance measured in the first step, and a third And a fourth step of calculating the concentration of suspended iron based on the absorbance measured in the step.

  According to this aspect, the absorbance corresponding to the total iron concentration is measured in the first step, the suspended component is removed by the filter in the second step, and the soluble iron concentration is corresponded in the third step. In the fourth step, the concentration of suspended iron can be calculated based on the two absorbances.

  According to the present invention, there is an effect that the concentrations of total iron, soluble iron, and suspended iron existing in water can be accurately measured without using a reagent.

It is a block diagram which shows the iron concentration measuring apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the light absorbency measurement part of the iron concentration measuring apparatus of FIG. It is a flowchart explaining the iron concentration measuring method by the iron concentration measuring apparatus of FIG. It is a block diagram which shows the modification of the iron concentration measuring apparatus of FIG. It is a block diagram which shows the other modification of the iron content concentration measuring apparatus of FIG.

An iron concentration measuring apparatus 1 and an iron concentration measuring method according to an embodiment of the present invention will be described below with reference to the drawings.
The iron concentration measuring device 1 according to the present embodiment is a device that measures the iron concentration contained in the feed water supplied to the boiler device (not shown) through the feed water path A, for example, as shown in FIG. , A pipeline system 2, a calculation storage unit (concentration calculation unit) 3, and a display unit 14.

  The pipe line system 2 includes a first flow path 4 connected to a water supply path to the boiler device, and a second flow path 5 that further branches from the first flow path 4 and then merges with the first flow path 4. And a filter section 6 provided in the second flow path 5, an absorbance measurement section 7 arranged downstream of the joining position of the first flow path 4 and the second flow path 5, and a flow from the water supply path There are provided two valves (channel switching units) 8 and 9 for switching the channel through which the sample water flows between the first channel 4 and the second channel 5.

  The filter unit 6 includes a filter (not shown) such as a membrane filter or a cartridge filter. The filter is preferably replaceable. By selecting the pore size of the filter, the particle size of suspended iron to be filtered can be narrowed down.

  As shown in FIG. 2, the absorbance measuring unit 7 includes a window 7b made of a transparent material provided in a part of the pipe 7a constituting the flow path, and the pipe 7a at the position of the window 7b. The light-emitting part 7c and the light-receiving part 7d arrange | positioned in the position which opposes on both sides of is provided. The light emitting part 7c is, for example, a light emitting diode, and irradiates the sample water flowing in the pipe line 7a through the window part 7b with light having a wavelength of 360 nm to 380 nm. The light receiving unit 7d is, for example, a photodiode or a photomultiplier tube, and detects the amount of light emitted from the light emitting unit 7c, passing through the sample water, and emitted outside the pipe line 7a through the window 7b. It is supposed to be.

  A port 10 for supplying the standard solution to the absorbance measuring unit 7 is disposed between the joining position of the first channel 4 and the second channel 5 and the absorbance measuring unit 7. The standard solution is a liquid containing a known concentration of iron. In order to dissolve iron in the state of iron ions, the standard solution is usually kept acidic. However, since the absorbance varies depending on the change in pH, the standard solution supplied to the port 10 is the same as the sample water. Use the one adjusted to pH 6-8 so as to be sex.

  The arithmetic storage unit 3 creates and stores calibration curves for total iron and soluble iron based on the amount of light received by the light receiving unit 7d of the absorbance measuring unit 7 when the standard solution is supplied from the port 10. It has become.

  When the sample water that has passed through the first flow path 4 is supplied to the absorbance measurement unit 7, the calculation storage unit 3 is based on the amount of light received by the light receiving unit 7 d and the calibration curve of total iron. Is calculated. The arithmetic storage unit 3 calculates the concentration of soluble iron based on the amount of light received by the light receiving unit 7d and the calibration curve of soluble iron when the sample water that has passed through the second flow path 5 is supplied. It is supposed to be. Further, the calculation storage unit 3 calculates the concentration of suspended iron by subtracting the concentration of soluble iron from the calculated concentration of total iron.

  The display unit 14 is, for example, a monitor, and displays the total iron concentration, the soluble iron concentration, and the suspended iron concentration calculated by the calculation storage unit 3, respectively.

An iron concentration measuring method using the iron concentration measuring apparatus 1 according to the present embodiment configured as described above will be described below.
The iron concentration measurement method according to the present embodiment is a method in which a part of water is sampled as sample water from a water supply path connected to a boiler and is measured.

  Prior to measuring the concentration of the sample water, the absorbance measurement unit 7 is calibrated (preparation of a calibration curve) periodically or as necessary. In the calibration, the valves 8 and 9 of the two flow paths 4 and 5 are closed, and a standard solution whose pH is neutrally adjusted is supplied from the port 10 to the absorbance measurement unit 7. In the absorbance measurement unit 7, light having a wavelength of about 370 nm is irradiated from the light emitting unit 7c toward the standard solution, and the light transmitted through the standard solution is received by the light receiving unit 7d. The electric signal output from the light receiving unit 7d is sent to the calculation storage unit 3 and stored as a calibration value of the total iron concentration. This is performed with a plurality of standard solutions having different concentrations, and a calibration curve of total iron is prepared. One of the concentrations of the standard solution may be zero.

  Next, the valve 8 of the first flow path 4 is closed, the valve 9 of the second flow path 5 is opened, and the standard solution is allowed to flow from the port 10 to the filter unit 6 provided in the second flow path 5. Then, the standard solution that has passed through the filter unit 6 is guided to the absorbance measurement unit 7. In the absorbance measurement unit 7, light having a wavelength of about 370 nm is irradiated from the light emitting unit 7c toward the sample water, and the transmitted light is received by the light receiving unit 7d. The electric signal output from the light receiving unit 7d is sent to the calculation storage unit 3 and stored as a calibration value of soluble iron. This is performed with a plurality of standard solutions having different concentrations, and a calibration curve for soluble iron is prepared. One of the concentrations of the standard solution may be zero.

Next, the concentration of the sample water is measured.
First, as shown in FIG. 3, the sample water is introduced into the first flow path 4 by opening the valve 8 of the first flow path 4 and closing the valve 9 of the second flow path 5. Then, it is directly guided to the absorbance measurement unit 7 (step S1). Then, in the absorbance measurement unit 7, light having a wavelength of about 370 nm is irradiated from the light emitting unit 7c toward the sample water, and the transmitted light is received by the light receiving unit 7d (step S2). The electric signal output from the light receiving unit 7d is sent to the calculation storage unit 3, calculated based on the above-described calibration curve of total iron, and stored as a measurement value of the total iron concentration (step S3).

  Next, by closing the valve 8 of the first flow path 4 and opening the valve 9 of the second flow path 5, the sample water is allowed to flow through the filter unit 6 provided in the second flow path 5, The sample water that has passed through the filter unit 6 is guided to the absorbance measurement unit 7 (step S4). Then, in the absorbance measurement unit 7, light having a wavelength of about 370 nm is irradiated from the light emitting unit 7c toward the sample water, and the transmitted light is received by the light receiving unit 7d (step S5). The electric signal output from the light emitting unit 7c is sent to the calculation storage unit 3, calculated based on the above-described soluble iron calibration curve, and stored as a measurement value of the concentration of soluble iron (step S6).

  In the operation storage unit 3, the concentration of suspended iron is calculated by subtracting the concentration of soluble iron calculated in step S6 from the total iron concentration calculated in step S3 (step S7).

  As described above, according to the iron concentration measuring apparatus 1 and the iron concentration measuring method according to the present embodiment, it is not necessary to use a reagent as in the conventional case, so that it is possible to reduce the running cost without burdening the environment. There is an advantage that you can. And there exists an advantage that the density | concentration of suspended iron which could not be measured conventionally can be measured with a density | concentration of soluble iron accurately.

  In addition, as a standard solution, a solution in which iron of a known concentration is dissolved in the state of iron ions is used to adjust the pH to neutral. Therefore, iron in the standard solution is partially suspended. doing. According to this embodiment, even in a standard solution containing such a suspended state, the total iron concentration of iron contained can be detected continuously and accurately without using a reagent. There is an advantage that the efficiency of the iron removal process of the boiler feed water can be improved by measuring the suspended iron concentration and the soluble iron concentration.

  In the present embodiment, the first flow path 4 and the second flow path 5 are merged, and the absorbance of the sample water before and after filtration is measured in a single absorbance measurement unit 7. However, instead of this, as shown in FIG. 4, separate absorbance measuring units 12 and 13 for measuring the absorbance may be arranged in each channel.

In the present embodiment, the valves 8 and 9 for switching the flow of the sample water to the flow paths 5 and 6 are provided in the flow paths 5 and 6, but instead, the flow is caused by a three-way valve. You may decide to switch.
Further, as shown in FIG. 5, a plurality of filters 6A and 6B having different hole diameters may be installed, and the absorbance may be measured for each filter 6a and 6b transmitted. That is, by switching the filters 9A and 6B that allow the sample water to pass by switching the valve 9 and the three-way valve 11, the absorbance measurement unit 7 can measure suspended iron for each particle size.

1 Iron Concentration Measuring Device 3 Operation Storage Unit (Concentration Calculation Unit)
4 First flow path 5 Second flow path 6 Filter section 6A, 6B Filter 7, 12, 13 Absorbance measurement section 8, 9 Valve (flow path switching section)
S2 1st step S4 2nd step S5 3rd step S7 4th step

Claims (4)

An absorbance measurement unit that measures absorbance by irradiating the sample water with light having a wavelength of 360 nm to 380 nm;
A concentration calculation unit for calculating an iron concentration based on the absorbance measured by the absorbance measurement unit;
A filter unit for filtering suspended components from the sample water,
The concentration calculator calculates the concentration of total iron from the absorbance measured by the absorbance measurement unit for the sample water before filtration by the filter unit, and the absorbance measurement unit for the sample water after filtration by the filter unit An iron concentration measuring device that calculates the concentration of soluble iron from the absorbance measured by the method, and calculates the concentration of suspended iron by subtracting the concentration of soluble iron from the concentration of total iron. The filter unit includes a plurality of filters having different hole diameters,
The concentration calculation unit calculates the concentration of soluble iron from the absorbance measured by the absorbance measurement unit for each sample water after passing through each filter, and calculates the concentration of each soluble iron from the concentration of total iron. The iron concentration measuring apparatus according to claim 1, wherein the concentration of suspended iron for each particle size is calculated by subtraction. A first absorbance measurement unit that measures absorbance by irradiating the sample water with light having a wavelength of 360 nm to 380 nm;
A filter unit for filtering suspended components from the sample water that has passed through the first absorbance measurement unit;
A second absorbance measuring unit that measures absorbance by irradiating light having a wavelength of 360 nm to 380 nm to the filtered sample water that has passed through the filter unit;
Based on the absorbance of the sample water after filtration measured by the second absorbance measurement unit, the concentration of soluble iron is calculated, and the absorbance of the sample water after filtration measured by the first absorbance measurement unit and An iron concentration measuring device comprising: a concentration calculating unit that calculates the concentration of suspended iron based on the absorbance of the sample water before filtration measured by the second absorbance measuring unit. A first step of irradiating the sample water with light having a wavelength of 360 nm to 380 nm to measure absorbance;
A second step of passing sample water through a filter to filter suspended components;
A third step of measuring the absorbance by irradiating the sample water filtered by the second step with light having a wavelength of 360 nm to 380 nm;
An iron concentration measurement method, comprising: a fourth step of calculating a concentration of suspended iron based on the absorbance measured in the first step and the absorbance measured in the third step.

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