JP6006605B2 - Steam flow measuring device and steam flow measuring method - Google Patents

Description

  One embodiment of the present invention relates to a measurement technique, for example, a technique for measuring a flow rate of wet steam.

  After the water reaches the boiling point, it becomes wet steam in which water vapor gas (gas phase portion: saturated steam) and water droplets (liquid phase portion: saturated water) are mixed. Here, the weight ratio of the water vapor gas to the wet steam is referred to as “dryness”. For example, if water vapor gas and water droplets are present in half, the dryness is 0.5. Moreover, when there is no water droplet and only water vapor gas is present, the dryness is 1.0. From the viewpoints of effectively utilizing the sensible heat and latent heat possessed by wet steam in heat exchangers, etc., and preventing corrosion of turbine blades in steam turbines, the wet steam dryness is controlled. It is desired to be in a state close to 1.0. Therefore, various methods for measuring the dryness have been proposed.

  For example, Patent Document 1 uses a saturated steam table based on the wet steam flow rate and pressure before and after the pressure control valve, using the fact that there is no change in the total enthalpy before and after the pressure control valve provided in the pipe. The technique which calculates | requires saturated water enthalpy and saturated steam enthalpy, and calculates dryness is disclosed.

JP-A-8-312908

  However, since the technique disclosed in Patent Document 1 needs to change the wet vapor to be measured from the two-phase state to the gas phase state and further stabilize the measurement object in the gas phase state, the dryness measurement is performed. There was a problem that it took a long time.

  Therefore, the present invention provides a steam flow measuring device and a steam flow measuring method capable of measuring the dryness at high speed and determining the flow rate of saturated steam and / or saturated water from the dryness and the mass flow rate of wet steam. One of the purposes is to do.

  In addition, not only the said objective but obtaining the solution means which has the solution principle shown to the form for implementing invention mentioned later can also be positioned as one of the other objectives of this invention.

  (1) In order to solve the above-described problem, the steam flow rate measuring device according to the first aspect of the present invention is a dryness measuring device that measures the dryness of the wet steam based on the received light intensity of light transmitted through the wet steam to be measured. A mass flow meter for measuring the mass flow rate of the wet steam, a mass flow rate calculation unit for calculating a mass flow rate of the saturated steam based on the measured dryness and the measured mass flow rate, and a specific volume of the saturated steam And a flow rate calculation unit that calculates the flow rate of the saturated steam based on the mass flow rate of the saturated steam.

  According to a first aspect of the present invention, there is provided a method for measuring a flow rate of steam, irradiating wet steam with light, measuring dryness of the wet steam based on a received light intensity of light transmitted through the wet steam, and the wet steam. The mass flow rate of the saturated steam, calculating the mass flow rate of the saturated steam based on the measured dryness and the measured mass flow rate, based on the specific volume of the saturated steam and the mass flow rate of the saturated steam Calculating the flow rate of the saturated steam.

  (2) In order to solve the above-mentioned problem, the steam flow rate measuring device according to the second invention is a dryness measuring device for measuring the dryness of the wet steam based on the received light intensity of light transmitted through the wet steam to be measured. A mass flow meter that measures the mass flow rate of the wet steam, a mass flow rate calculation unit that calculates a mass flow rate of saturated water based on the measured dryness and the measured mass flow rate, and a specific volume of saturated water And a flow rate calculation unit that calculates the flow rate of the saturated water based on the mass flow rate of the saturated water.

  According to a second aspect of the present invention, there is provided a steam flow rate measuring method comprising: irradiating wet steam with light; measuring dryness of the wet steam based on a received light intensity of light transmitted through the wet steam; and the wet steam. Measuring the mass flow rate of the water, calculating the mass flow rate of the saturated water based on the measured dryness and the measured mass flow rate, and based on the specific volume of the saturated water and the mass flow rate of the saturated water Calculating the flow rate of the saturated water.

The present invention may include the following components as desired.
(3) The dryness measuring apparatus includes: a light emitter that irradiates the wet steam with light of a plurality of wavelengths; a light receiving element that receives the light of the plurality of wavelengths that has passed through the wet steam; A dryness calculating unit that calculates the dryness based on the received light intensity of each wavelength light.

  (4) The light having a plurality of wavelengths irradiated by the illuminant includes a first wavelength at which an absorption peak of water molecules appears when the number of hydrogen bonds is 0, and an absorption peak of water molecules when the number of hydrogen bonds is 1. And a third wavelength different from the first and second wavelengths.

It is a figure which shows an example of the steam flow measuring apparatus which concerns on Embodiment 1. FIG. It is a graph which shows the state change of the water in standard atmospheric pressure. It is a schematic diagram of a cluster of water molecules. It is a schematic diagram which shows the state of the water molecule depending on dryness. It is a graph which shows the example of the relationship between the average number of hydrogen bonds which the cluster of a water molecule has, and temperature. It is a graph which shows the example of the absorption spectrum of a water molecule. It is a schematic diagram of the water molecule which exists independently. It is a schematic diagram of the two water molecules couple | bonded by one hydrogen bond. It is a schematic diagram of the three water molecules couple | bonded by two hydrogen bonds. It is a graph which shows the example of an absorption spectrum. It is a graph which shows the example of ratio of the specific enthalpy of steam, and a light absorbency. It is a figure which shows an example of the steam flow measuring apparatus which concerns on Embodiment 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. In other words, the present invention can be implemented with various modifications (combining the embodiments, etc.) without departing from the spirit of the present invention. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic and do not necessarily match actual dimensions and ratios. In some cases, the dimensional relationships and ratios may be different between the drawings.

(Definition)
The main terms used in this specification are defined as follows.
“Vapor”: In each embodiment, it means water vapor, but is not limited to water vapor as long as it is a two-phase state of a gas phase portion and a liquid phase portion.
“Dryness”: Refers to the weight ratio of the vapor phase portion and the liquid phase portion in the vapor. There is a relationship of dryness [%] = 100 [%] − wetness [%].
“Wet steam”: refers to steam having a dryness χ of 0 to 100%.
“Saturated steam”: refers to the gas phase portion of wet steam. Also called dry saturated steam (saturated dry steam).
“Saturated water”: refers to the liquid phase of wet steam.
“Specific volume”: The volume of a substance of unit mass. Also called specific volume (product).
“Mass flow rate”: refers to the mass flowing per unit time, and is represented by [kg / s] in this embodiment.
“Flow rate”: Volume flow rate, that is, the volume flowing per unit time, which is represented by [m ³ / s] in the present embodiment.

(Embodiment 1)
The first embodiment relates to a steam flow rate measuring device for measuring the flow rate of saturated steam constituting wet steam.

(Constitution)
As shown in FIG. 1, a steam flow measurement device (also referred to as a steam flow measurement system) 1 according to the first embodiment includes a dryness measurement device 10, a mass flow meter 20, a mass flow calculation unit 30, and a flow rate. A calculation unit 40 is provided.

  The dryness measuring device 10 is a device that measures the dryness χ of wet steam based on the received light intensity of light that has passed through the wet steam to be measured. The dryness measuring apparatus 10 exemplarily dries based on the light emitter 11 that irradiates the wet steam in the pipe 21 with light, the light receiving element 12 that receives the light transmitted through the wet steam, and the received light intensity of the received light. A dryness calculating unit 13 for calculating the degree χ.

  The light emitter 11 emits light of at least two different wavelengths, for example. For example, one of at least two different wavelengths is a wavelength at which an absorption peak of a water molecule appears when the number of hydrogen bonds is 0 (for example, 1880 nm), and the other wavelengths are when the number of hydrogen bonds is 1. The wavelength at which the absorption peak of water molecules appears (for example, 1910 nm). Thus, the light emitted from the light emitter 11 is set such that the absorbance at each of the plurality of wavelengths correlates with the number of hydrogen bonds formed by water molecules in the cluster.

  In order to generate light having a plurality of different wavelengths, the light emitter 11 may include a plurality of light emitting elements that emit light having different wavelengths or a light emitting element that emits light in a wide wavelength band. As the light emitter 11, a light emitting diode, a super luminescent diode, a semiconductor laser, a laser oscillator, a fluorescent discharge tube, a low-pressure mercury lamp, a xenon lamp, a light bulb, and the like can be used.

  An optical waveguide 31 may be connected to the light emitter 11. The optical waveguide 31 propagates the light emitted from the light emitter 11 into the pipe 21. For example, the optical waveguide 31 passes through the side wall of the pipe 21. Alternatively, a light transmissive window may be provided on the side wall of the pipe 21 and the optical waveguide 31 may be connected to the window.

  The light propagated through the optical waveguide 31 enters the pipe 21 from the end of the optical waveguide 31. For the optical waveguide 31, a plastic optical fiber made of polymethyl methacrylate resin (PMMA: Poly (methacrylate)), a glass optical fiber made of quartz glass, and the like can be used. If propagation is possible, it is not limited to this.

  An optical waveguide 32 into which light that has passed through the inside of the pipe 21 enters may be connected to the pipe 21. The optical waveguide 32 guides the light transmitted through the wet steam inside the pipe 21 to the light receiving element 12. The end portion of the optical waveguide 32 faces the end portion of the optical waveguide 31. For example, the optical waveguide 32 passes through the side wall of the pipe 21. Alternatively, a light transmissive window may be provided on the side wall of the pipe 21 and the optical waveguide 32 may be connected to the window.

  The light emitter 11 may be disposed on the side wall of the pipe 21 and the optical waveguide 31 may not be provided. The light receiving element 12 may be disposed on the side wall of the pipe 21 and the optical waveguide 32 may not be provided. In FIG. 1, the light emitter 11 and the light receiving element 12 face each other, but a light emitting and receiving element in which both the light emitter and the light receiving element are integrated may be used. In this case, a reflector may be disposed on the side wall of the pipe facing the light emitting / receiving element. The light emitted from the light emitting / receiving element travels inside the pipe, is reflected by the reflecting plate, and is received by the light emitting / receiving element.

  For the light receiving element 12, a photodiode or the like can be used. When the light emitter 11 emits light in a wide wavelength band, a filter that transmits at least two different wavelengths may be disposed in front of the light receiving element 12. For example, the light receiving element 12 includes at least light having a wavelength of 1880 nm where water molecules absorb most when the number of hydrogen bonds is 0, and light having a wavelength of 1910 nm where water molecules absorb most when the number of hydrogen bonds is 1. Is received.

  The dryness calculation unit 13 calculates the dryness χ based on the received light intensity of each of the received light of one or a plurality of wavelengths based on the measurement principle described later.

  The mass flow meter 20 measures the mass flow rate M of wet steam.

  In the first embodiment, the mass flow rate calculation unit 30 is configured to calculate the saturated vapor mass flow rate Wd based on the measured dryness χ and the measured mass flow rate M.

  In the first embodiment, the flow rate calculation unit 40 is configured to calculate the saturated steam flow rate Qd based on the calculated saturated steam mass flow rate Wd.

  Among the components described above, the dryness calculation unit 13, the mass flow rate calculation unit 30, and the flow rate calculation unit 40 of the dryness measurement device 10 are functionally realized by the arithmetic device 300 executing a predetermined software program. Functional block. The arithmetic device 300 includes, for example, an input device 321, an output device 322, a program storage device 323, a temporary storage device 324, and a data storage device 400.

  The input device 321 is input means for an operator to operate a predetermined instruction. As an example of the input device 321, a switch, a keyboard, and the like can be used. The relationship between the absorbance ratio R and the dryness χ can be input using the input device 321, for example.

  The output device 322 is output means that indicates the processing result of the computer device 300 to the operator. As an example of the output device 322, a light indicator, a digital indicator, a liquid crystal display device, or the like can be used. The output device 322 includes, for example, the dryness χ of the wet steam inside the pipe 21 calculated by the dryness calculator 13, the saturated steam mass flow Wd calculated by the mass flow calculator 30, and the saturated steam flow calculated by the flow calculator 40. Qd etc. are displayed.

  The program storage device 323 is a memory that stores a software program for causing the computer device 300 to function as the functional block. The temporary storage device 324 is a memory that temporarily stores data when the computer device 300 executes a software program.

  The data storage device 400 is a memory connected so that it can be referred to from the arithmetic unit 300, and includes a relationship storage unit 401. The relationship storage unit 401 is a storage area for storing a relationship table and the like necessary for the dryness calculation unit 13, the mass flow rate calculation unit 30, and the flow rate calculation unit 40 to perform arithmetic processing. The relationship storage unit 401, for example, has previously acquired the absorbance ratio R expressed by any one of formulas (1) to (4) described later and the dryness χ referred to by the dryness calculation unit 13. Remember the relationship. The relationship storage unit 401 also stores, for example, the relationship between the specific volume v ′ of saturated water and the specific volume v ″ of saturated steam according to temperature and pressure, which will be described later, referred to by the flow rate calculation unit 40. The relationship may be stored as an expression, or may be stored as table format data (table data).

  The temperature sensor 22 is disposed on the pipe 21, measures the temperature of the wet steam inside the pipe 21, and outputs it to the arithmetic device 300.

  The pressure sensor 23 is disposed on the pipe 21, measures the pressure of the wet steam inside the pipe 21, and outputs it to the arithmetic device 300.

(Optical measurement principle of dryness χ by dryness measuring device 10)
As shown in FIG. 2, after the water reaches the boiling point, water (saturated water) as a droplet and steam (saturated steam) are mixed and become coexistent. This coexisting steam is wet steam. Since the ratio of the gas phase portion (saturated steam) to the total amount of wet steam is the dryness, the dryness is 1 when the total amount of wet steam is saturated steam, and the dryness is 0 when the total amount of wet steam is saturated water. .

  As shown in FIG. 3, water molecules can be bonded through hydrogen bonds to form clusters. The phase of water changes due to the difference in the number of hydrogen bonds formed by water molecules. For example, as shown in FIG. 4, when the dryness is 0, a large number of water molecules are bonded, and when the dryness is 1, the water molecules are bonded. There are relatively few clusters.

  As shown in FIG. 5, in the wet steam, the average number of hydrogen bonds that the clusters in the wet steam with a dryness of 0 have, for example, 2.13 under atmospheric pressure. The average number of hydrogen bonds possessed by the cluster tends to decrease as the dryness approaches 1, and the number of water molecules present alone tends to increase.

  FIG. 6 shows an example of a change in absorption spectrum according to the number of hydrogen bonds of water molecules. As shown in FIG. 6, a water molecule giving an absorption spectrum having a peak at 1840 or 1880 nm exists alone as shown in FIG. Water molecules that give an absorption spectrum having a peak at 1910 nm are two water molecules that are bonded by one hydrogen bond as shown in FIG. The water molecules giving an absorption spectrum having a peak at 1950 nm are three water molecules bonded by two hydrogen bonds as shown in FIG. As shown in FIG. 6, the wavelength of the peak of the absorption spectrum tends to increase as the number of hydrogen bonds contained in the cluster formed by water molecules increases.

FIG. 10 is an actual measurement example of the absorption spectrum of the wet steam having the first to fourth specific enthalpies and the superheated steam having the fifth specific enthalpy by the spectrometer. The first specific enthalpy was the lowest, and the specific enthalpy of the steam was increased toward the fifth specific enthalpy by heating with the heater. FIG. 11 shows the integrated value of the absorption spectrum in the wavelength range of 1750 to 1770 nm shown in FIG. 10, I _S0 , the integrated value of the absorption spectrum in the wavelength range of 1870 to 1890 nm, I _S1 , and the wavelength in the range of 1910 to 1930 nm. The integrated value of the absorption spectrum of I ₂ is I _S2 , and the ratio R given by the following formula (1) is plotted against the specific enthalpy of the vapor.

R = (I _S1 −I _S0 ) / (I _S2 −I _S0 ) (1)

The integrated value I _S0 of the absorption spectrum in the wavelength range of 1750 to 1770 nm is a part unrelated to the molecular absorption of water and affects the increase / decrease of the absorption spectrum to be captured. The integrated value I _S1 of the absorption spectrum in the wavelength range of 1870 to 1890 nm correlates with the concentration of water molecules present alone. The integral value I _S2 of the absorption spectrum in the wavelength range of 1910 to 1930 nm correlates with the concentration of two water molecules bonded by one hydrogen bond.

  As shown in FIG. 11, the absorbance ratio R tends to increase as the specific enthalpy of the vapor increases. Therefore, it was shown that the higher the specific enthalpy of vapor, the higher the ratio of the concentration of water molecules present alone to the concentration of two water molecules bonded by one hydrogen bond.

In addition, without using an integral value, the absorbance of light having a wavelength of 1760 nm is I ₀ , the absorbance of light having a wavelength of 1880 nm is I ₁ , and the absorbance of light having a wavelength of 1910 nm is I ₂ , and is given by the following formula (2). Similar results can be obtained by plotting the resulting ratio R against the specific enthalpy of steam.

R = (I ₁ −I ₀ ) / (I ₂ −I ₀ ) (2)

The reason for taking the difference between I _S1 and I _S0 and the difference between I _S2 and I _{S0 in} equation (1) is to make the baseline of the spectroscopic spectrum constant. Therefore, when there is no possibility that the baseline of the spectrum will vary, the wavelength is 1870 to 1890 nm with respect to the integrated value I _S2 of the absorption spectrum in the range of 1910 to 1930 nm, as shown in the following formula (3). A similar result can be obtained by plotting the ratio R of the integral value I _S1 of the absorption spectrum of the range against the specific enthalpy of the vapor.

R = I _S1 / I _S2 (3)

Furthermore, without using an integral value, the absorbance of light having a wavelength of 1880 nm is I ₁ , the absorbance of light having a wavelength of 1910 nm is I ₂ , and the ratio R given by the following equation (4) is expressed with respect to the specific enthalpy of steam. The same result can be obtained by plotting.

R = I ₁ / I ₂ (4)

  As described above, the absorbance ratio R correlates with the ratio of water molecules present alone that do not form hydrogen bonds to clusters composed of two water molecules bonded by one hydrogen bond. The average number of hydrogen bonds possessed by the cluster tends to decrease as the dryness approaches 0 to 1, and the number of water molecules present alone tends to increase. Therefore, the absorbance ratio R tends to increase as the dryness approaches from 0 to 1.

  The light emitter 11 shown in FIG. 1 has, as light having at least two different wavelengths, for example, light having a wavelength (for example, 1880 nm) at which an absorption peak of water molecules appears when the number of hydrogen bonds is 0, and the number of hydrogen bonds being 1 And light having a wavelength (eg, 1910 nm) at which an absorption peak of water molecules appears. Thus, the light emitted from the light emitter 11 is set such that the absorbance at each of the plurality of wavelengths correlates with the number of hydrogen bonds formed by water molecules in the cluster.

  As described above, the average number of hydrogen bonds of a water molecule cluster decreases as the dryness approaches 0 to 1, the number of water molecules present alone increases, and the absorbance ratio R has a dryness of 0 to 1. It tends to increase as it approaches. Therefore, as the dryness of the wet steam inside the pipe 21 approaches from 0 to 1, more light having a wavelength of 1880 nm at which the absorption spectrum of water molecules present alone is peaked is absorbed and bonded by one hydrogen bond. There is a tendency that light having a wavelength of 1910 nm at which the absorption spectra of the two water molecules have a peak is less absorbed.

  The dryness calculation unit 13 calculates the dryness χ of the wet steam based on the magnitude relationship between the plurality of measured values of the intensity of light transmitted through the wet steam at different wavelengths. For example, the dryness calculation unit 13 receives from the light receiving element 12 an intensity spectrum of light transmitted through the wet steam inside the pipe 21. Further, the dryness calculation unit 13 absorbs light by the wet steam based on the intensity spectrum of the light before passing through the wet steam inside the pipe 21 and the intensity spectrum of the light transmitted through the wet steam inside the pipe 21. Calculate the spectrum. Furthermore, the dryness calculation unit 13 calculates the value of the absorbance ratio R represented by any of the above formulas (1) to (4) based on the absorption spectrum.

  The dryness calculation unit 13 reads the relationship between the absorbance ratio R and the dryness from the relationship storage unit 401. The dryness calculation unit 13 calculates the value of the wet steam inside the pipe 21 based on the calculated absorbance ratio R and the relationship between the absorbance ratio R and the dryness. The calculated wet steam dryness χ can be displayed on the output device 322, for example.

(Measurement principle of saturated steam mass flow rate Wd by mass flow rate calculation unit 30)
The mass flow rate calculation unit 30 calculates the saturated vapor mass flow rate Wd based on the dryness χ measured by the dryness calculation unit 13 and the mass flow rate M measured by the mass flow meter 20. Specifically, there is a relationship represented by the following formula (5) among the saturated vapor mass flow rate Wd, the dryness χ, and the mass flow rate M.

Saturated steam mass flow rate Wd [kg / s] = dryness χ × mass flow rate M [kg / s] (5)

  Therefore, the mass flow rate calculation unit 30 can calculate the saturated steam mass flow rate Wd [kg / s] from the measured dryness χ and the mass flow rate M by the above equation (5). The calculated saturated vapor mass flow rate Wd can be displayed on the output device 322, for example.

(Measurement principle of saturated steam flow rate Qd by flow rate calculation unit 40)
The flow rate calculation unit 40 calculates the saturated steam flow rate Qd based on the saturated steam mass flow rate Wd calculated by the mass flow rate calculation unit 30 and the saturated steam specific volume v ″. Specifically, the saturated steam flow rate Qd, There is a relationship represented by the following formula (6) between the saturated steam mass flow rate Wd and the specific volume v ″ of the saturated steam.

Saturated steam flow rate Qd [m ³ / s] = saturated steam mass flow rate Wd [kg / s] × saturated steam specific volume v ″ (6)

Therefore, the flow rate calculation unit 40 is obtained by referring to the relationship storage unit 401 based on the saturated vapor mass flow rate Wd, the temperature measured by the temperature sensor 22, and the pressure measured by the pressure sensor 23 according to the above equation (6). The saturated steam flow rate Qd [m ³ / s] can be calculated from the specific volume v ″ of the saturated steam. The calculated saturated steam flow rate Qd can be displayed on the output device 322, for example.

(effect)
According to the first embodiment described above, the dryness of the wet steam is measured at high speed without changing the phase state of the wet steam by an optical method, and the measured dryness and the mass flow rate of the wet steam are used. It becomes possible to obtain the flow rate of saturated steam. That is, without requiring time to stabilize the temperature, the dryness χ of the wet steam is accurately measured, and the saturated steam flow Qd based on the dryness χ and the mass flow M measured by the mass flow meter 20. Can be measured with high accuracy and at high speed.

  Moreover, according to Embodiment 1, since it is not necessary to provide a throttle valve or a diversion pipe in the pipe, it can be installed at low cost.

  Further, in the conventional dryness measurement, the measurement range is narrow, for example, it is possible to measure only a range of dryness of 0.9 to 1.0, whereas in the dryness measurement according to the first embodiment described above, the optical range is optical. In order to observe the state of water molecules, it is possible to measure the dryness in the whole range of 0 to 1.0.

  Furthermore, in the conventional dryness meter using ultrasonic waves, there is a large difference in acoustic impedance at the boundary surface between the saturated vapor that is the gas phase part and the saturated water that is the liquid phase part. It has been reflected and has not reached a level at which dryness can be practically measured. On the other hand, according to Embodiment 1, since the light which can permeate | transmit the boundary surface of saturated steam and saturated water is used, it is possible to measure dryness more correctly than the case where an ultrasonic wave is used.

(Embodiment 2)
Embodiment 2 relates to a steam flow rate measuring device for measuring the flow rate of saturated water constituting wet steam.

(Constitution)
As shown in FIG. 12, a steam flow measurement device (also referred to as a steam flow measurement system) 1A according to the second embodiment includes a dryness measurement device 10, a mass flow meter 20, a mass flow calculation unit 30A, and a flow rate. A calculation unit 40A is provided. About the dryness measuring apparatus 10 and the mass flowmeter 20, since it is the same structure as the said Embodiment 1, description is abbreviate | omitted.

  The mass flow rate calculation unit 30A is configured to calculate the saturated water mass flow rate Ww based on the measured dryness χ and the measured mass flow rate M based on the measurement principle described later.

  The flow rate calculation unit 40A is configured to calculate the saturated water flow rate Qw based on the calculated saturated water mass flow rate Ww based on the measurement principle described later.

  Among the components described above, the dryness calculation unit 13, the mass flow rate calculation unit 30A, and the flow rate calculation unit 40A of the dryness measurement device 10 are functionally realized by the arithmetic device 300A executing a predetermined software program. Functional block. Since the hardware configuration of the arithmetic device 300A is the same as that of the first embodiment, description thereof is omitted.

  In the data storage device 400, the relationship storage unit 401A has saturated water corresponding to the temperature and pressure referred to by the flow rate calculation unit 40A, in addition to the relationship between the absorbance ratio R and the dryness χ referred to by the dryness calculation unit 13. The relationship between the specific volume v ′ and the specific volume v ″ of saturated steam is stored.

(Measurement principle of saturated water mass flow rate Ww by mass flow rate calculation unit 30A)
The mass flow rate calculation unit 30A calculates the saturated water mass flow rate Ww based on the dryness χ measured by the dryness calculation unit 13 and the mass flow rate M measured by the mass flow meter 20. Specifically, there is a relationship represented by the following formula (7) among the saturated water mass flow rate Ww, the dryness χ, and the mass flow rate M.

  Saturated water mass flow rate Ww [kg / s] = (1−dryness χ) × mass flow rate M [kg / s] (7)

  Therefore, the mass flow rate calculation unit 30A can calculate the saturated water mass flow rate Ww [kg / s] from the measured dryness χ and the mass flow rate M by the above equation (7). The calculated saturated water mass flow rate Ww can be displayed on the output device 322, for example.

(Measurement principle of saturated water flow rate Qw by flow rate calculation unit 40A)
The flow rate calculation unit 40A calculates a saturated water flow rate Qw based on the saturated water mass flow rate Ww calculated by the mass flow rate calculation unit 30A and the saturated water specific volume v ′. Specifically, there is a relationship represented by the following formula (8) among the saturated water flow rate Qw, the saturated water mass flow rate Ww, and the saturated water specific volume v ′.

Saturated water flow rate Qw [m ³ / s] = saturated water mass flow rate Ww [kg / s] × saturated water specific volume v ′ (8)

Therefore, the flow rate calculation unit 40A is obtained by referring to the relationship storage unit 401A based on the saturated water mass flow rate Ww, the temperature measured by the temperature sensor 22, and the pressure measured by the pressure sensor 23 by the above equation (8). The saturated water flow rate Qw [m ³ / s] can be calculated from the saturated water specific volume v ′. The calculated saturated water flow rate Qw can be displayed on the output device 322, for example.

(effect)
According to the second embodiment described above, the dryness of the wet steam is measured at high speed without changing the phase state of the wet steam by an optical method, and the measured dryness and the mass flow rate of the wet steam are used. The flow rate of saturated water can be obtained. That is, the dryness χ of the wet steam is accurately measured without requiring time to stabilize the temperature, and the saturated water flow rate Qw is determined based on the dryness χ and the mass flow rate M measured by the mass flow meter 20. Can be measured with high accuracy and at high speed.
Other effects are the same as those of the first embodiment.

(Other variations)
The present invention is not limited to the above-described embodiment, and can be variously modified and applied.

  (1) For example, in the above-described embodiment, an example in which the absorbance at a wavelength of 1880 nm and the absorbance at a wavelength of 1910 nm are compared has been shown. The degree of dryness may be calculated based on the relationship.

  (2) Moreover, you may compare the light absorbency of the wavelength correlated with the hydrogen bond number 0, and the light absorbency of the wavelength correlated with the hydrogen bond number 2. Or you may compare the light absorbency of the wavelength correlated with the hydrogen bond number 0 with the light absorbency of the wavelength correlated with the hydrogen bond number 3.

  (3) Further, the absorbance at a wavelength correlated with the number of hydrogen bonds 1 may be compared with the absorbance at a wavelength correlated with the number of hydrogen bonds 2, or the absorbance at a wavelength correlated with the number of hydrogen bonds 1, The absorbance at a wavelength correlated with the number of hydrogen bonds 3 may be compared, or the absorbance at a wavelength correlated with the number of hydrogen bonds 2 may be compared with the absorbance at a wavelength correlated with the number of hydrogen bonds 3. .

  As described above, the dryness may be calculated based on the ratio of the absorbances of arbitrary plural wavelengths correlated with different numbers of hydrogen bonds. Alternatively, it is also possible to obtain a correlation between the difference in absorbance at a plurality of wavelengths correlated with different numbers of hydrogen bonds and the dryness in advance, and obtain the value of the dryness from the measured value of the difference in absorbance at a plurality of wavelengths. Good.

  (4) Moreover, in the said embodiment, although the dryness was calculated based on the light reception intensity | strength of the light of a several wavelength, it is not restricted to this. For example, the wet vapor to be measured is irradiated with light of a single wavelength, and the dryness is obtained based on the received light intensity of the light of the single wavelength transmitted through the wet vapor and the temperature or pressure of the wet vapor. It can also be configured as follows.

  In this case, the wavelength of the light emitted from the light emitter 11 is set to a wavelength at which the absorption peak of water molecules appears when the number of hydrogen bonds is 0 (in other words, a wavelength at which the vapor has a large absorption), or the number of hydrogen bonds is 1 In this case, it can be set to a wavelength at which an absorption peak of water molecules appears (in other words, a wavelength at which liquid water has a large absorption). A non-limiting example of the former is 1880 nm, and a non-limiting example of the latter is 1910 nm.

  As described above, the average number of hydrogen bonds of the water molecule cluster decreases as the dryness approaches from 0 to 1. For example, when the light emitter 11 emits light having a wavelength of 1880 nm, the light having a wavelength of 1880 nm tends to be absorbed more as the dryness of the wet vapor in the pipe 21 approaches 0 to 1. For example, when the light emitter 11 emits light having a wavelength of 1910 nm, the light having a wavelength of 1910 nm tends to be absorbed less as the dryness of the wet vapor in the pipe 21 approaches 0 to 1. Further, for example, when the light emitter 11 emits light having a wavelength of 1910 nm, as the dryness approaches 0 to 1, the absorption by the wet steam decreases and the light reception intensity by the light receiving element 12 increases. The relationship between the magnitude of the received light intensity or the light absorbance and the dryness is determined according to the light of the wavelength used.

  Therefore, if the relationship between the received light intensity or the light absorbance and the dryness is stored in advance, the dryness χ of the wet steam to be measured can be obtained.

  (5) In the above-described embodiments, water vapor is cited as an example of wet steam. However, the present invention is not limited to this, and each of the above-described embodiments is also applied to the case where the amount of heat of a two-phase refrigerant is measured. Is possible.

  (6) Furthermore, when the dryness is measured optically, the absorbance of the vapor that is the measurement target region is very large compared to the absorbance in the non-measurement target region, and therefore measurement error due to a small amount of impurities contained in the vapor Is small or can be ignored.

  However, when vapor contamination (turbidity) progresses, measurement errors due to impurities may not be negligible. In such a case, setting a wavelength that is not affected by impurities as a reference wavelength for measurement error correction enables measurement with higher accuracy.

The reference wavelength is a first wavelength (for example, 1875 nm, 1380 nm, 1135 nm, 940 nm, 905 nm, etc.) that has a relatively large absorption in the vapor, and a second wavelength (for example, a relatively large absorption in the liquid moisture) , 1940 nm, 1470 nm, 1200 nm, etc.) can be set to a third wavelength (for example, 1300 nm, 2100 nm, etc.). Each of the first, second, and third wavelengths may be one wavelength or a plurality of wavelengths. The reference wavelength that is the third wavelength (wavelength 3) may be set when, for example, light having two or more wavelengths is used for optical measurement of dryness. For example, the reference wavelength may be set in the above embodiment.
(Industrial application fields)

  The present invention can be used for boilers. According to the present invention, since the flow rate of saturated steam and the flow rate of saturated water can be measured, the thermal efficiency is improved, and the superheater can be controlled appropriately. Further, the water level and the like can be controlled with higher accuracy. In other words, it is possible to achieve optimum dryness control and optimum boiler efficiency of the heat exchanger. Therefore, it is possible to perform control that is accurate and energy-saving according to the load, such as stably supplying steam with high dryness.

  The present invention can also be used as an index for food management. For example, in a food manufacturing process or a chemical process including a steaming process or a vulcanization process, the quality of a manufactured product or the like can vary depending on the dryness of wet steam.

  Furthermore, the present invention can be applied to heavy and large industrial fields. In this field, the wet steam dryness at the steam turbine outlet depends on the power generation efficiency, so by measuring the turbine dryness (steam turbine wet loss measurement), the turbine inlet according to the load is measured. Flow rate control is possible.

DESCRIPTION OF SYMBOLS 1, 1A said flow measuring device 10 dryness measuring device 11 light emitter 12 light receiving element 13 dryness calculating part 20 mass flow meter 21 pipe 22 temperature sensor 23 pressure sensor 31, 32 optical waveguide 300, 300A calculating part 30, 30A mass flow rate Calculation unit 40, 40A Flow rate calculation unit 321 Input device 322 Output device 323 Program storage device 324 Temporary storage device 400 Data storage device 401, 401A Relationship storage unit

Claims (6)

A temperature sensor for measuring the temperature of the wet steam to be measured;
A pressure sensor for measuring the pressure of the wet steam;
A light receiving intensity of the light in the wavelength band that is absorbed by the water that has passed through the wet steam, and the dryness measuring device for measuring the dryness of the wet steam on the basis of the temperature or pressure of the wet steam,
A mass flow meter for measuring the mass flow rate of the wet steam;
A mass flow rate calculation unit for calculating a mass flow rate of saturated steam based on the measured dryness and the measured mass flow rate;
A relationship storage unit for storing a specific volume of saturated steam according to temperature and pressure;
A flow rate calculation unit that calculates a flow rate of the saturated steam based on a specific volume of the saturated steam stored in the relation storage unit according to the measured temperature and pressure and a mass flow rate of the saturated steam. The
Steam flow measuring device. A temperature sensor for measuring the temperature of the wet steam to be measured;
A pressure sensor for measuring the pressure of the wet steam;
A light receiving intensity of the light in the wavelength band that is absorbed by the water that has passed through the wet steam, and the dryness measuring device for measuring the dryness of the wet steam on the basis of the temperature or pressure of the wet steam,
A mass flow meter for measuring the mass flow rate of the wet steam;
A mass flow rate calculation unit for calculating a mass flow rate of saturated water based on the measured dryness and the measured mass flow rate;
A relationship storage unit for storing a specific volume of saturated water according to temperature and pressure;
A flow rate calculation unit that calculates a flow rate of the saturated water based on a specific volume of saturated water stored in the relationship storage unit according to the measured temperature and pressure and a mass flow rate of the saturated water. The
Steam flow measuring device. The dryness measuring device is
A light emitter that irradiates the wet steam with light of a plurality of wavelengths;
A light receiving element that receives light of the plurality of wavelengths that has passed through the wet steam;
A dryness calculating unit that calculates the dryness based on the received light intensity of each of the received light of the plurality of wavelengths,
The steam flow measuring device according to claim 1 or 2.   The light having a plurality of wavelengths irradiated by the illuminant has a first wavelength at which an absorption peak of water molecules when the number of hydrogen bonds is 0, and an absorption peak of water molecules when the number of hydrogen bonds is 1. The steam flow rate measuring apparatus according to claim 3, comprising a second wavelength and a third wavelength different from the first and second wavelengths. Measuring the temperature of the wet steam to be measured;
Measuring the pressure of the wet steam;
And applying light of a wavelength band that is absorbed by the water to the wet steam,
Measuring the dryness of the wet steam based on the received light intensity of the light transmitted through the wet steam and the temperature or pressure of the wet steam;
Measuring the mass flow rate of the wet steam;
Calculating a mass flow rate of saturated steam based on the measured dryness and the measured mass flow rate;
Preparing a specific volume of saturated steam according to temperature and pressure;
Calculating a flow rate of the saturated steam based on a specific volume of the prepared saturated steam according to the measured temperature and pressure and a mass flow rate of the saturated steam.
Steam flow measurement method. Measuring the temperature of the wet steam to be measured;
Measuring the pressure of the wet steam;
And applying light of a wavelength band that is absorbed by the water to the wet steam,
Measuring the dryness of the wet steam based on the received light intensity of the light transmitted through the wet steam and the temperature or pressure of the wet steam;
Measuring the mass flow rate of the wet steam;
Calculating a saturated water mass flow based on the measured dryness and the measured mass flow;
Preparing a specific volume of saturated water according to temperature and pressure;
A method for measuring a steam flow rate, comprising: calculating a flow rate of the saturated water based on a specific volume of the prepared saturated water corresponding to the measured temperature and pressure and a mass flow rate of the saturated water.