CN114764060A

CN114764060A - Gas analysis device

Info

Publication number: CN114764060A
Application number: CN202111628845.1A
Authority: CN
Inventors: 米谷康弘; 井之上哲志; 生田卓司; 阪仓诚司
Original assignee: Horiba Ltd
Current assignee: Horiba Ltd
Priority date: 2021-01-12
Filing date: 2021-12-28
Publication date: 2022-07-19
Also published as: JP2022108038A

Abstract

The invention provides a gas analyzer, which is compact and can prevent the increase of maintenance workload. The analysis device (100, 200) is provided with a light source (3), a first pneumatic detector (53), a second pneumatic detector (55), a third pneumatic detector (57), and a calculation unit (7). A light source (3) outputs measurement light (Lm). The first pneumatic detector measures the intensity of the measurement light absorbed by the first component gas (Gs 1). The second pneumatic detector measures the intensity of the measurement light absorbed by the second component gas (Gs 2). The third pneumatic detector measures, as the intensity of the first passing measurement light (Lm1), the intensity of measurement light absorbed by a third component gas (Gs3) whose light absorption characteristics at least partially overlap with the light absorption characteristics of the first and second component gases. A calculation unit (7) calculates information relating to a third component gas (Gs3) from the intensity of the first passing measurement light.

Description

Gas analysis device

Technical Field

The present invention relates to a gas analyzer for analyzing components contained in a sample gas.

Background

Conventionally, a predetermined component (for example, Sulfur Oxide (SO)) contained in a sample gas (for example, exhaust gas) sampled from a predetermined portion (for example, a flue or the like)_x) Nitrogen Oxide (NO) _x) Devices that utilize the light absorption characteristics (e.g., infrared light absorption characteristics) of the components are known as devices for performing analysis. For example, an analysis device that detects the infrared light absorption characteristics of the components using a sensor called a pneumatic detector is known.

The sample gas generally contains a component to be analyzed (referred to as an analysis target component) and another component that absorbs light. Depending on the sample gas, the light absorption characteristics (e.g., absorption wavelength range) of the component to be analyzed and the light absorption characteristics of components other than the component to be analyzed may overlap. The above-mentioned components are called interference components, and influence (called interference influence) on the analysis result of the analysis target component.

In order to reduce the influence of the repetition of the light absorption characteristics, an analysis device provided with a pneumatic detector for detecting the light absorption characteristics of the interference components in addition to a pneumatic detector for detecting the light absorption characteristics of the analysis target components is known (for example, see patent document 1). The analysis device can analyze the analysis target component with high accuracy based on a difference between a detection result obtained from a pneumatic detector for detecting the light absorption characteristic of the analysis target component and a detection result obtained from a pneumatic detector for detecting the light absorption characteristic of the interference component.

Patent document 1: japanese laid-open patent publication No. 2012 and 68164

In the past, attempts have been made to analyze a plurality of analysis target components contained in a sample gas by using an analyzer that detects the light absorption characteristics by a pneumatic detector as described above. Even in the case of analyzing a plurality of analysis target components, it is necessary to detect the light absorption characteristics of the analysis target components and the light absorption characteristics of interference components with respect to the analysis target components for each analysis target component. On the other hand, it is desirable that the analyzer be as compact as possible even if the amount of the component to be analyzed increases, and that the increase in the amount of maintenance work for the analyzer be suppressed as much as possible.

Disclosure of Invention

The purpose of the present invention is to make an analyzer as compact as possible and to suppress an increase in the amount of maintenance work for the analyzer in an analyzer that analyzes a plurality of types of components to be analyzed using a pneumatic detector that measures light absorption characteristics.

Various means are described below as means for solving the technical problem. These means may be combined arbitrarily as required.

A gas analyzer according to an embodiment of the present invention is an apparatus for analyzing components contained in a sample gas. The analyzer includes a measuring cell, a light source, a first pneumatic detector, a second pneumatic detector, a third pneumatic detector, and a calculating unit.

The measuring cell introduces a sample gas into the inside. The light source radiates measuring light toward the inside of the measuring cell. The first pneumatic detector measures the intensity of measurement light absorbed by the first component gas contained in the sample gas in the measurement cell. The second pneumatic detector measures the intensity of measurement light absorbed by the second component gas contained in the sample gas in the measurement cell. The third pneumatic detector measures, as the intensity of the first passing measurement light, the intensity of measurement light that is absorbed by the third component gas in the measurement cell, the intensity of measurement light that is included in the sample gas and has a light absorption characteristic for the measurement light that at least partially overlaps with the light absorption characteristics for the measurement light by the first component gas and the second component gas, and the first passing measurement light is measurement light that has passed through the second pneumatic detector. The calculation unit calculates information relating to the third component gas based on the intensity of the first passing measurement light measured by the third pneumatic detector.

Thus, the amount of absorption of the measurement light by the third component gas, the light absorption characteristics of which overlap with the light absorption characteristics of the first component gas and the second component gas at least partially, that is, which interferes with the component gases, can be measured by one pneumatic detector. As a result, the analyzer can be made compact.

The calculation unit may calculate information related to the first component gas based on the intensity of the measurement light measured by the first pneumatic detector and the intensity of the first passing measurement light measured by the third pneumatic detector. Thus, the calculation unit can calculate the information on the first component gas interfering with the third component gas with high accuracy.

The first pneumatic detector may include a first sealed cell in which the first component gas is sealed and through which the measurement light passes. This enables the intensity of the measurement light absorbed by the first component gas to be measured with high accuracy.

The second pneumatic detector may include a second sealed cell in which the second component gas is sealed and through which the measurement light passes. This enables the intensity of the measurement light absorbed by the second component gas to be measured with high accuracy.

The third pneumatic detector may be provided with a third sealed cell in which the second component gas is sealed. Thus, the intensity of the measurement light absorbed by the third component gas can be measured from the intensity of the measurement light absorbed by the second component gas that interferes with the third component gas.

The concentration of the second component gas in the second sealed cell may be equal to or less than half of the concentration of the second component gas in the third sealed cell. Thus, the intensity of the measurement light absorbed by the third component gas can be measured with high accuracy by the third pneumatic detector.

The first component gas may be sulfur dioxide, the second component gas may be nitrogen oxide, and the third component gas may be water vapor. Thus, information on the water vapor contained in the sample gas can be calculated from the intensity of the measurement light measured by one pneumatic detector.

The gas analysis device may include a fourth pneumatic detector. The fourth pneumatic detector measures, as the intensity of the second passing measurement light, the intensity of the measurement light absorbed by a fourth component gas that is included in the sample gas and that has a light absorption characteristic for the measurement light that at least partially overlaps with a light absorption characteristic for the measurement light of the first component gas, the intensity of the measurement light having passed through the first pneumatic detector.

Thereby, the intensity of the measurement light absorbed by the fourth component gas interfering with the first component gas can be measured.

The calculation unit may calculate the information related to the first component gas based on the intensity of the measurement light measured by the first pneumatic detector, the intensity of the measurement light measured by the second pneumatic detector, the intensity of the first passage measurement light measured by the third pneumatic detector, and the intensity of the second passage measurement light measured by the fourth pneumatic detector.

Thus, the information on the first component gas can be calculated with high accuracy, taking into account the amounts of absorption of the measurement light by the third component gas and the fourth component gas that interfere with the first component gas.

The fourth component gas may be methane. Thus, the information on the first component gas can be calculated with high accuracy, taking into account the amount of absorption of the measurement light by methane that interferes with the first component gas.

The above-described analysis apparatus can be made compact because it is not necessary to provide a pneumatic detector for detecting the light absorption characteristics of the interference component for each analysis target component. In addition, maintenance work of the analyzer can be reduced.

Drawings

Fig. 1 is a diagram showing the structure of an analysis device.

Fig. 2 is a diagram showing an example of the light absorption characteristics of each component gas.

Fig. 3 is a flowchart showing an analysis operation of the component gas.

Fig. 4 is a diagram showing an example of a time-dependent change in the concentration of nitrogen oxides calculated by correcting the concentration calculated using the signal value Sig (Gs2) by the correction amount calculated from the fifth signal value, and a time-dependent change in the actual concentration of nitrogen oxides.

Fig. 5 is a diagram showing an example of a temporal change in concentration calculated using the signal value Sig (Gs2) and a temporal change in actual concentration of nitrogen oxides.

Fig. 6 is a diagram showing a connection relationship between the sampling unit and the analyzer.

Description of the reference numerals

100. 200 analysis device

1 measuring cell

1a introduction port

1b discharge port

3 light source

5 sensor unit

51 optical branching member

53 first pneumatic detector

53a first sealed pool

55 second pneumatic detector

55a second enclosure pool

57 third pneumatic detector

57a third sealed pool

59 fourth pneumatic detector

59a fourth enclosing pool

F1 first filter

F2 second filter

7 arithmetic unit

9 light-condensing member

91 optical path

93 photo detector

F filter

W optical window

101 sampling unit

1011 Probe

1013 trapping filter

1015 pretreatment device

Gs sample gas

Gs1 first component gas

Gs2 second component gas

Gs3 third component gas

Gs4 fourth component gas

Gs5 fifth component gas

Lm measuring light

Lm1 first pass measurement light

Lm2 second pass measurement light

Sp measurement space

Detailed Description

1. First embodiment

(1) Structure of analyzer

The configuration of the analyzer 100 according to the first embodiment will be described below with reference to fig. 1. Fig. 1 is a diagram showing the structure of an analysis device. The analysis device 100 is a device as follows: the light absorption characteristics of the component gas are used to analyze the component gas contained in the sample gas Gs such as the atmosphere, the exhaust gas flowing through the flue, the process gas generated in various processes, the exhaust gas generated by the combustion of garbage and the like, the exhaust gas generated by the combustion of the boiler, and the gas filled in the gas bomb. Specifically, the analyzer 100 is an analyzer that: the intensity of the infrared light absorbed by the component gas is measured using a pneumatic detector to measure information (e.g., concentration) related to the content of the component gas in the sample gas Gs.

The component gas that can be analyzed by the analysis device 100 of the first embodiment is, for example, sulfur dioxide (SO)₂) Nitrogen Oxide (NO)_x) Gases (e.g. Nitric Oxide (NO), nitric oxide diacids (NO)₂) Dinitrogen monoxide (N)₂O), etc.). In addition, there are carbon monoxide (CO) and carbon dioxide (CO)₂) Hydrocarbon gas (e.g., methane (CH)₄) Propane (C)₃H₈) Etc.) and the like.

The analysis device 100 according to the first embodiment can analyze a plurality of component gases contained in the sample gas Gs. The analysis device 100 described below uses two types of the first component gas Gs1 and the second component gas Gs2 contained in the sample gas Gs as analysis targets. In the following examples, the first component gas Gs1 is sulfur dioxide (SO)₂) The second component gas Gs2 is Nitric Oxide (NO).

The second component gas Gs2 may be Nitrogen Oxide (NO) other than nitric oxide_x). In this case, the nitrogen oxide (second component gas Gs2) contained in the sample gas Gs may be converted into nitric oxide by an NOx converter (not shown).

The following describes a specific configuration of the analyzer 100. As shown in fig. 1, the analyzer mainly includes a measuring cell 1, a light source 3, a sensor unit 5, and a calculation unit 7.

The measuring cell 1 is a hollow member into which the sample gas Gs can be introduced. The measuring cell 1 has an inlet 1a for introducing the sample gas Gs therein, and an outlet 1b for discharging the sample gas Gs introduced therein to the outside. The measuring cell 1 is provided with infrared transmission windows (such as calcium fluoride crystal windows) at two ends, and is in a sealed structure. The internal space of the hollow member into which the sample gas Gs is introduced is referred to as a measurement space Sp.

In the measurement cell 1, the sample gas Gs present at a portion (for example, a flue) to which the inlet 1a is connected can be introduced into the measurement space Sp by, for example, sucking the measurement space Sp by a pump (not shown) connected to the outlet 1 b. Further, the sample gas Gs may be introduced into the measurement space Sp by the pressure at the site to which the inlet 1a is connected. In this case, it is not particularly necessary to suck the gas from the discharge port 1 b.

As described above, since the infrared transmission windows are attached to both ends of the measurement cell 1 in the longitudinal direction, the measurement light Lm radiated from the light source 3 can pass through the measurement space Sp. For example, an optical filter or the like may be provided in the longitudinal direction of the measuring cell 1, and only light in a wavelength range that can be absorbed by the component gas of the measurement light Lm may be passed through the measurement space Sp.

The light source 3 is provided at one end of the measuring cell 1 in the longitudinal direction. The light source 3 radiates measurement light Lm including light in a wavelength range that is absorbable by at least the first component gas Gs1 and the second component gas Gs2 to the measurement space Sp of the measurement cell 1. The constituent gas that can be analyzed by the analysis device 100 as shown above absorbs light in the infrared wavelength range. Therefore, the measurement light Lm used in the present embodiment is infrared light. Any light source may be used as the light source 3 as long as it can radiate infrared light.

The sensor unit 5 is provided on the opposite side of the measuring cell 1 in the longitudinal direction from the side on which the light source 3 is provided. The sensor unit 5 measures the intensity of the measurement light Lm that has passed through the measurement space Sp. The sensor unit 5 will be described specifically below.

The arithmetic unit 7 is a computer system including a CPU, a storage device (such as a RAM or a ROM), and various interfaces (such as a D/a converter and an a/D converter). The arithmetic unit 7 performs various information processes in the analysis device 100. Specifically, the calculation unit 7 performs information processing on an electric signal relating to the intensity of the measurement light Lm measured by the sensor unit 5, and calculates the absorption amount of the measurement light Lm by the first component gas Gs1 and the second component gas Gs 2. The calculation unit 7 calculates information on the contents of the first component gas Gs1 and the second component gas Gs2 based on the absorption amount. The computing unit 7 also has a function of controlling each component of the analyzer 100.

Part or all of the various information processes executed by the arithmetic unit 7 may be realized by a program stored in a storage device of a computer system constituting the arithmetic unit 7. The arithmetic unit 7 may implement part or all of the various information processing described above by a hardware method. The operation unit 7 may be an SoC (System on Chip) in which a CPU, a memory device, various interfaces, a circuit for realizing part or all of the above-described processing of the operation unit 7, and the like are formed on one Chip.

As shown in fig. 1, the analyzer 100 of the present embodiment further includes a light collecting member 9. The light collecting member 9 is made of a material that reflects infrared light, and the inner wall of the light collecting member 9 is tapered, and the surface of the tapered inner wall is subjected to surface treatment (for example, mirror surface treatment or the like) that reflects the measurement light Lm. Further, an optical path 91 is provided midway on the tapered inner wall of the light collecting member 9. The light collecting member 9 guides the measurement light Lm reflected by the tapered inner wall surface into the optical path 91.

As shown in FIG. 1, the exit of the optical path 91 is in contact with the surface of the introduction port 1 a. Further, a photodetector 93 is provided on the surface opposite to the inlet 1a via a filter F so as to face the exit of the optical path 91. The inlet 1a has a cell structure having a predetermined cell length. Optical windows W are provided at both ends of the introduction port 1a so as to introduce the measurement light Lm having passed through the optical path 91 to the photodetector 93.

The photodetector 93 measures the intensity of the measurement light Lm which has passed through the inside of the introduction port 1a and the filter F from the exit of the optical path 91. The photodetector 93 is, for example, a pyroelectric sensor. The filter F is an optical filter that passes only a component in a wavelength range absorbed by the fifth component gas Gs5 contained in the sample gas Gs in the measurement light Lm.

With the above configuration, the photodetector 93 can measure the intensity of the measurement light Lm absorbed by the fifth component gas Gs5 contained in the sample gas Gs passing through the inside of the introduction port 1 a. The fifth component gas Gs5 is, for example, carbon dioxide (CO) which is an interference component with respect to the second component gas Gs2 (nitric oxide) (at least a part of the light absorption characteristics of the second component gas Gs2 and the light absorption characteristics of the fifth component gas overlap)₂)。

In the case where the fifth component gas Gs5 does not need to be measured in the analyzer 100, the light collecting member 9, the optical path 91, and the photodetector 93 described above may not be provided.

(2) Structure of sensor unit

Next, a specific configuration of the sensor unit 5 included in the analysis device 100 will be described with reference to fig. 1. The sensor unit 5 measures the intensity of the measurement light Lm (i.e., the amount of absorption of the measurement light Lm) after the components (the first component gas Gs1, the second component gas Gs2, and the like) contained in the sample gas Gs are absorbed while the measurement light Lm passes through the measurement cell 1. As will be described later, the sensor unit 5 of the present embodiment is constituted by a pneumatic detector. The pneumatic detector has a cell (referred to as an enclosed cell) in which an analysis target or a component having a light absorption characteristic the same as or similar to that of the analysis target is enclosed. The pneumatic detector is a sensor as follows: the intensity of the measurement light Lm incident on the detector is measured by acquiring a signal relating to a physical quantity (for example, an amount of expansion due to heat generation) generated by the absorption of the measurement light Lm by the components sealed in the cell while the measurement light Lm passes through the cell. With this structure, the pneumatic detector has high selectivity for an analysis object.

As shown in fig. 1, the sensor section 5 has an optical path member 51, a first pneumatic detector 53, and a second pneumatic detector 55. The optical branching member 51 branches the measurement light Lm having passed through the cell 1 in a direction in which the first pneumatic detector 53 is arranged (in the example of fig. 1, a direction perpendicular to the longitudinal direction of the cell 1) and a direction in which the second pneumatic detector 55 is arranged (in the example of fig. 1, the longitudinal direction of the cell 1). The light branching member 51 is a member for propagating light in a plurality of directions, such as a half mirror.

The first pneumatic detector 53 is disposed apart from the optical branching member 51 by a predetermined distance in a direction perpendicular to the longitudinal direction of the measuring cell 1 when viewed from the optical branching member 51. The first pneumatic detector 53 includes a first sealed cell 53a in which a first component gas Gs1 (sulfur dioxide in the present embodiment) is sealed. In the present embodiment, the first sealed cell 53a is sealed with a gas obtained by mixing a few% of the first component gas Gs1 (sulfur dioxide) with an inert gas (for example, argon (Ar) gas). The first sealed cell 53a is formed of a material (optical window) through which the measurement light Lm is transmitted, and the measurement light Lm from the optical branching member 51 is incident into the first sealed cell 53a, passes through the inside of the first sealed cell 53a, and is then emitted from the first sealed cell 53 a. Therefore, if a sensor is disposed behind the first pneumatic detector 53, the measurement light Lm is incident on the sensor.

The first pneumatic detector 53 having the above-described configuration can measure the intensity of the measurement light Lm in the wavelength range absorbed by the first component gas Gs1 in the measurement light Lm passing through the measurement cell 1.

In the analysis device 100 according to the present embodiment, the first filter F1 is provided between the optical branching member 51 and the first pneumatic detector 53. The first filter F1 is an optical filter that passes light in a wavelength range absorbed by the first component gas Gs1 in the measurement light Lm. Thus, in the first pneumatic detector 53, light in the wavelength range absorbed by the first component gas Gs1 in the measurement light Lm is incident on the first sealed cell 53 a. As a result, the first pneumatic detector 53 can measure the intensity of the measurement light Lm absorbed by the first component gas Gs1 with high accuracy.

The second pneumatic detector 55 is disposed apart from the optical branching member 51 by a predetermined distance in the longitudinal direction of the measuring cell 1 when viewed from the optical branching member 51. The second pneumatic detector 55 includes a second sealed cell 55a in which a second component gas Gs2 (nitric oxide in the present embodiment) is sealed. In the present embodiment, a gas obtained by mixing several tens% of second component gas Gs2 (nitric oxide) with an inert gas (for example, argon (Ar) gas) is sealed in the second sealed cell 55 a. The second sealed cell 55a is formed of a material (optical window) through which the measurement light Lm is transmitted, and the measurement light Lm from the optical branching member 51 enters the second sealed cell 55a, passes through the inside of the second sealed cell 55a, and then is emitted from the second sealed cell 55 a. Therefore, if a sensor is disposed behind the second pneumatic detector 55, the measurement light Lm is incident on the sensor.

The second pneumatic detector 55 having the above-described configuration can measure the intensity of the measurement light Lm in the wavelength range absorbed by the second component gas Gs2 in the measurement light Lm passing through the measurement cell 1.

In the analysis device 100 according to the present embodiment, a second filter F2 is provided between the optical branching member 51 and the second pneumatic detector 55. The second filter F2 is an optical filter that passes light in a wavelength range absorbed by the second component gas Gs2 in the measurement light Lm. Thus, in the second pneumatic detector 55, light in the wavelength range absorbed by the second component gas Gs2 in the measurement light Lm enters the second sealed cell 55 a. As a result, the second pneumatic detector 55 can measure the intensity of the measurement light Lm absorbed by the second component gas Gs2 with high accuracy.

Due to the configuration of the detector, the measurement result of the intensity of the measurement light Lm by the aerodynamic detector is influenced not only by the absorption of the measurement light Lm by the component gas to be analyzed, but also by the absorption of the measurement light Lm by other components (also referred to as interference components). The phenomenon is caused by at least a part of the light absorption characteristics (wavelength range of light absorption) of the interference component overlapping with at least a part of the light absorption characteristics of the component gas to be analyzed.

For example, as shown in FIG. 2, sulfur dioxide (SO) is used as the first component gas Gs1₂) The absorption wavelength range of the infrared light is 7-8 μm, and the infrared light in the wavelength range can be absorbed by water vapor (H)₂O) (third component gas Gs3) and methane (CH)₄) (fourth component gas Gs 4). Fig. 2 is a diagram showing an example of the light absorption characteristics of each component gas. Further, the light absorption wavelength range of Nitric Oxide (NO) as the second component gas Gs2 is 5 to 6 μm, and infrared light in the wavelength range can be absorbed by water vapor (G2)H₂O) (third component gas Gs 3).

Thus, the absorption wavelength range of the first component gas Gs1 is equivalent to that of the third component gas Gs3 (water vapor) and the fourth component gas Gs4 (methane (CH)₄) A part of the absorption wavelength range of) is repeated, the measurement result of the measurement light Lm by the first pneumatic detector 53 is affected not only by the absorption of the measurement light Lm by the first component gas Gs1 but also by the absorption of the third component gas Gs3 (water vapor) and the fourth component gas Gs 4. Further, since the absorption wavelength range of the second component gas Gs2 overlaps with a part of the absorption wavelength range of the third component gas Gs3 (water vapor), the measurement result of the measurement light Lm by the second pneumatic detector 55 is affected not only by the absorption of the measurement light Lm by the second component gas Gs2 but also by the absorption of the third component gas Gs3 (water vapor).

The sample gas Gs sampled from a flue or the like contains Nitrogen Oxides (NO) such as sulfur dioxide and nitric oxide_x) In addition, a substance (such as water vapor or methane) which is an interference component with respect to the component gas may be included. Therefore, the sensor section 5 of the present embodiment has, as shown in fig. 1, a third pneumatic detector 57 that detects the influence of the third component gas Gs3 as an interference component and a fourth pneumatic detector 59 that detects the influence of the fourth component gas Gs4 as an interference component, in addition to the first pneumatic detector 53 and the second pneumatic detector 55. In the present embodiment, the third component gas Gs3 is water vapor, and the fourth component gas Gs4 is methane.

The third pneumatic detector 57 is disposed behind the second pneumatic detector 55 in the propagation direction of the measurement light Lm. That is, the third pneumatic detector 57 receives the measurement light Lm (referred to as first passing measurement light Lm1) emitted from the second sealed cell 55a of the second pneumatic detector 55.

The third pneumatic detector 57 has a third sealed cell 57a in which the second component gas Gs2 is sealed at an arbitrary concentration. As shown in fig. 2, since the light absorption characteristics of nitric oxide and the light absorption characteristics of water vapor (third component gas Gs3) overlap, the absorption of the measurement light Lm by the third component gas Gs3 (water vapor) can be detected by sealing the second component gas Gs2 in the third sealed cell 57a at an arbitrary concentration.

The third sealed cell 57a is formed of a material (optical window) through which the measurement light Lm is transmitted, and the first passing measurement light Lm1 emitted from the second pneumatic detector 55 is incident into the third sealed cell 57a and propagates inside the third sealed cell 57 a. During this time, the first passing measurement light Lm1 is absorbed by the second component gas Gs2 sealed in the third sealed cell 57 a. The first passing measurement light Lm1 is the measurement light Lm passed through the measurement cell 1 and the second pneumatic detector 55. Therefore, the third pneumatic detector 57 having the above-described configuration can measure the intensity of the measurement light Lm in the wavelength range absorbed by the third component gas Gs3 in the measurement light Lm passing through the measurement cell 1 as the intensity of the first passing measurement light Lm 1.

In the present embodiment, 95% to 100% of the second component gas Gs2 is sealed in the third sealed cell 57 a. On the other hand, the concentration of the second component gas Gs2 sealed in the second sealing cell 55a is about several tens% (e.g., 12%). That is, the concentration of the second component gas Gs2 in the second sealed cell 55a is about 1/8 of the concentration of the second component gas Gs2 in the third sealed cell 57 a.

The concentration of the second component gas Gs2 enclosed in the second enclosed cell 55a and the third enclosed cell 57a may be arbitrary if the concentration of the second component gas Gs2 in the second enclosed cell 55a is less than half the concentration of the second component gas Gs2 in the third enclosed cell 57 a.

In this way, by reducing the concentration of the second component gas Gs2 in the second sealed cell 55a and increasing the concentration of the second component gas Gs2 in the third sealed cell 57a, the intensity of the first passing measurement light Lm1 can be maintained at a sufficient level while the detection sensitivity of the second pneumatic detector 55 to the second component gas Gs2 is ensured and the absorption of the measurement light Lm in the second sealed cell 55a is suppressed. As a result, the third pneumatic detector 57 can measure the intensity of the measurement light Lm absorbed by the third component gas Gs3 contained in the sample gas Gs with high accuracy.

The fourth pneumatic detector 59 is disposed behind the first pneumatic detector 53 in the propagation direction of the measurement light Lm. That is, the fourth pneumatic detector 59 receives the measurement light Lm (referred to as second passing measurement light Lm2) emitted from the first sealed cell 53a of the first pneumatic detector 53. The fourth pneumatic detector 59 includes a fourth sealed cell 59a in which a fourth component gas Gs4 (methane) is sealed.

The fourth sealed cell 59a is formed of a material (optical window) through which the measurement light Lm is transmitted, and the second passage measurement light Lm2 emitted from the first pneumatic detector 53 is incident into the fourth sealed cell 59a and propagates inside the fourth sealed cell 59 a. During this time, the second passing measurement light Lm2 is absorbed by the fourth component gas Gs4 sealed in the fourth sealed cell 59 a. The second measurement light Lm2 is the measurement light Lm that has passed through the measurement cell 1 and the first pneumatic detector 53. Therefore, the fourth pneumatic detector 59 having the above-described configuration can measure the intensity of the measurement light Lm in the wavelength range absorbed by the fourth component gas Gs4 in the measurement light Lm passing through the measurement cell 1 as the intensity of the second passing measurement light Lm 2.

In the present embodiment, the fourth enclosing cell 59a encloses almost 100% of the fourth component gas Gs 4. On the other hand, the concentration of the first component gas Gs1 sealed in the first sealed cell 53a is about a few% (e.g., 5%). That is, the concentration of the first component gas Gs1 in the first sealed cell 53a is about 1/20 of the concentration of the fourth component gas Gs4 in the fourth sealed cell 59 a. The concentration of the first component gas Gs1 in the first sealed cell 53a and the concentration of the fourth component gas Gs4 in the fourth sealed cell 59a may be appropriately determined in consideration of the detection sensitivity of each detector and the like.

In this way, by decreasing the concentration of the first component gas Gs1 in the first sealed cell 53a and increasing the concentration of the fourth component gas Gs4 in the fourth sealed cell 59a, the intensity of the second passing measurement light Lm2 can be maintained at a sufficient level while suppressing absorption of the measurement light Lm in the first sealed cell 53a while ensuring the detection sensitivity of the first gas dynamic detector 53 to the first component gas Gs 1. As a result, the fourth pneumatic detector 59 can measure the intensity of the measurement light Lm absorbed by the fourth component gas Gs4 contained in the sample gas Gs with high accuracy.

(3) Analysis operation of component gas by analysis device

Next, an analysis operation of the component gas using the analysis device 100 having the above-described configuration will be described with reference to fig. 3. Fig. 3 is a flowchart showing an analysis operation of the component gas. The analyzer 100 initially introduces the sample gas Gs into the measurement cell 1. Subsequently, in step S1, the light source 3 outputs measurement light Lm toward the measurement cell 1.

Next, in step S2, the first and

second air detectors

53 and 55 detect the measurement light Lm that has passed through the measurement space Sp of the measurement cell 1, and output a signal corresponding to the intensity of the detected measurement light Lm. The third pneumatic detector 57 detects the first passing measurement light Lm1 after passing through the second sealed cell 55a, and outputs a signal corresponding to the intensity of the detected first passing measurement light Lm 1. The fourth pneumatic detector 59 detects the second passing measurement light Lm2 after passing through the first sealed cell 53a, and outputs a signal corresponding to the intensity of the detected second passing measurement light Lm 2. The photodetector 93 then outputs a signal corresponding to the intensity of the measurement light Lm incident on the optical path 91 by the light collecting means 9.

The arithmetic unit 7 receives signals output from the first to fourth pneumatic detectors 53 to 59 and the photodetector 93. Hereinafter, the value of the signal (signal value) output from the first pneumatic detector 53 is assumed to be the first signal value Sig1, the value of the signal output from the second pneumatic detector 55 is assumed to be the second signal value Sig2, the value of the signal output from the third pneumatic detector 57 is assumed to be the third signal value Sig3, the value of the signal output from the fourth pneumatic detector 59 is assumed to be the fourth signal value Sig4, and the value of the signal output from the photodetector 93 is assumed to be the fifth signal value Sig 5.

After the signal is input from the detector, the arithmetic unit 7 analyzes the first component gas Gs1 and the second component gas Gs2 using the above-described signal. Specifically, the calculation unit 7 calculates information (for example, concentration) concerning the contents of the first component gas Gs1 and the second component gas Gs2 in the sample gas Gs using the signals. Specifically, the arithmetic unit 7 calculates information on the content of the first component gas Gs1 from the intensity of the measurement light Lm measured by the first aerodynamic detector 53, the intensity of the measurement light Lm measured by the second aerodynamic detector 55, the intensity of the first passing measurement light Lm1 measured by the third aerodynamic detector 57, and the intensity of the second passing measurement light Lm2 measured by the fourth aerodynamic detector 59.

More specifically, as described below, the arithmetic unit 7 first calculates a difference (referred to as a first differential value) between the third signal value Sig3 input from the third pneumatic detector 57 and a value obtained by multiplying the second signal value Sig2 input from the second pneumatic detector 55 by a coefficient k 3. Next, a difference (referred to as a second differential value) between the first signal value Sig1 input from the first aerodynamic detector 53 and a value obtained by multiplying the first differential value by a coefficient k1 is calculated. Further, a value obtained by multiplying the fourth signal value Sig4 by the coefficient k2 is subtracted from the second difference value, and a signal value (referred to as Sig (Gs1)) for calculating the content of the first component gas Gs1 is calculated.

Sig(Gs1)＝{Sig1－k1＊(Sig3－k3＊Sig2)}－k2＊Sig4

In another embodiment, as described below, a difference (referred to as a third differential value) between the first signal value Sig1 and a value obtained by multiplying the fourth signal value Sig4 by a coefficient k 2' is first calculated. Further, a difference (referred to as a fourth differential value) between the third signal value Sig3 and a value obtained by multiplying the second signal value Sig2 by a coefficient k 3' is calculated. Further, the signal value Sig (Gs1) may be calculated by subtracting the value obtained by multiplying the fourth difference value by the coefficient k 1' from the third difference value. In this case, the coefficient k1 ' may be different from the coefficient k1, the coefficient k2 ' may be different from the coefficient k2, and the coefficient k3 ' may be different from the coefficient k 3.

Sig(Gs1)＝(Sig1－k2’＊Sig4)－k1’＊(Sig3－k3’＊Sig2)

On the other hand, the arithmetic unit 7 calculates information on the content of the second component gas Gs2 from the intensity of the measurement light Lm measured by the second pneumatic detector 55, the intensity of the first passing measurement light Lm1 measured by the third pneumatic detector 57, and the intensity of the measurement light Lm measured by the photodetector 93. Specifically, the calculation unit 7 calculates a difference between the second signal value Sig2 input from the second pneumatic detector 55 and the value obtained by multiplying the third signal value Sig3 input from the third pneumatic detector 57 by the coefficient k4, and then subtracts a value obtained by multiplying the fifth signal value Sig5 input from the photodetector 93 by the coefficient k5 from the difference to calculate a signal value (referred to as Sig (Gs2)) for calculating the content of the second component gas Gs2, as described below.

Sig(Gs2)＝(Sig2－k4＊Sig3)－k5＊Sig5

As another embodiment, as described below, the signal value Sig (Gs2) may be calculated by calculating the difference between the second signal value Sig2 input from the second pneumatic detector 55 and the value obtained by multiplying the fifth signal value Sig5 input from the photodetector 93 by the coefficient k5 ', and then subtracting the value obtained by multiplying the third signal value Sig3 input from the third pneumatic detector 57 by the coefficient k 4' from the difference. In this case, the coefficient k4 'may be different from the coefficient k4, and the coefficient k 5' may be different from the coefficient k 5.

Sig(Gs2)＝(Sig2－k5’＊Sig5)－k4’＊Sig3

As described above, in the analysis device 100 of the present embodiment, the information on the third component gas Gs3 (in the present embodiment, the influence of the third component gas Gs3 on the detection result of the first component gas Gs1, and the influence of the third component gas Gs3 on the detection result of the second component gas Gs2) is determined based on the intensity of the first passing measurement light Lm1 measured by the third pneumatic detector 57. That is, in the analysis device 100, information on interference components common to a plurality of component gases to be analyzed is calculated using the measurement result of the measurement light Lm by one aerodynamic detector. This minimizes the number of detectors provided in the analyzer 100, thereby making the analyzer 100 compact. Further, by reducing the number of detectors provided in the analyzer 100, the amount of maintenance work for the analyzer 100 can be reduced.

2. Second embodiment

In the first embodiment described above, the information on the third component gas Gs3 is used as the information on the interference components when calculating the information on the contents of the first component gas Gs1 and the second component gas Gs2 contained in the sample gas Gs. However, the present invention is not limited to this, and the analysis device 200 according to the second embodiment can acquire information related to the content of the third component gas Gs3 contained in the sample gas Gs. For example, in the analysis device 200, the first component gas Gs1, the second component gas Gs2, and/or the fourth component gas Gs4 are set as interference components with respect to the third component gas Gs3, whereby information on the content of the third component gas Gs3 can be calculated.

For example, the arithmetic unit 7 calculates the influence of the interference component on the measurement result of the third component gas Gs3 (referred to as f (Sig1, Sig2, Sig4), and f (x) is a function of x) using the first signal value Sig1 input from the first pneumatic detector 53, the second signal value Sig2 input from the second pneumatic detector 55, and/or the fourth signal value Sig4 input from the fourth pneumatic detector 59. Next, the arithmetic unit 7 can calculate information on the content of the third component gas Gs3 by subtracting the influence f (Sig1, Sig2, Sig4) of the interference component from the third signal value Sig3 input from the third pneumatic detector 57.

The configuration and function of the analyzer 200 of the second embodiment are the same as those of the analyzer 100 of the first embodiment, except that the calculation unit 7 calculates information on the content of the third component gas Gs 3. Therefore, the explanation of the other structures and functions of the analyzer 200 will be omitted here.

3. Third embodiment

In the above embodiment, the first to third component gases Gs1 to Gs3 are analyzed based on new signal values calculated by subtracting the signal values due to the interference components from the first to third signal values Sig1 to Sig 3. However, the present invention is not limited to this, and the analysis result based on the new signal value may be further modified. For example, the analysis device 100 calculates Nitrogen Oxides (NO) generated from the gas turbine_x) In the case of the concentration of the second component gas Gs2, the concentration of nitrogen oxides calculated using the signal value Sig (Gs2) can be corrected using the measurement results of the other components, and the gas turbine obtains output by burning Liquefied Natural Gas (LNG).

When the concentration of nitrogen oxides generated from the gas turbine is calculated using the signal value Sig (Gs2), the calculated concentration of nitrogen oxides may become a value larger than the actual concentration. The deviation of the concentration calculated using signal value Sig (Gs2) from the actual concentration becomes significant particularly at low load operation of the gas turbine.

In an investigation of the cause of the deviation, it was found that the deviation occurs when carbon monoxide and unburned hydrocarbons are produced at a higher concentration (for example, on the order of several thousand ppm) than expected due to incomplete combustion of liquefied natural gas in the gas turbine during low-load operation. That is, it is considered that high concentrations of carbon monoxide and unburned hydrocarbons generated by incomplete combustion are causes of a deviation in analysis results. In addition, it is considered that incomplete combustion does not occur during normal operation, and these components are less likely to be generated. Further, it was found that when carbon monoxide and unburned hydrocarbons are generated at a higher concentration than expected due to incomplete combustion in the low load operation, the amount of carbon dioxide generated from the gas turbine is reduced as compared with the normal operation in which incomplete combustion is not generated. Therefore, it is considered that there is a correlation between the amounts of carbon monoxide and unburned hydrocarbons produced and the amount of carbon dioxide produced.

Therefore, in the third embodiment, the concentration calculated from the above-described Sig (Gs2) is corrected based on the concentration of carbon dioxide calculated using the fifth signal value Sig5 input from the photodetector 93 using the correlation between the amount of carbon dioxide generated and the amount of carbon monoxide and unburned hydrocarbons generated, and the concentration of nitrogen oxides is calculated. Specifically, the concentration of nitrogen oxides was calculated using the following formula. In the following formula, Conc (NO) _x) As the concentration of nitrogen oxides, Conc (Sig (Gs2)) is a concentration calculated from a signal value Sig (Gs2), Conc (Sig5) is a concentration of carbon dioxide calculated from a fifth signal value Sig5, and f (Conc (Sig5)) is a correction amount of the concentration of nitrogen oxides and is a function of the concentration of carbon dioxide calculated from a fifth signal value Sig 5.

Conc(NOx)＝Conc(Sig(Gs2))－f(Conc(Sig5))

The function f (Conc (Sig5)) indicating the correction amount of the concentration of nitrogen oxides can be calculated as an approximation formula of the following data by using a minimum two-way method, for example: this data represents the relationship between the concentration of carbon dioxide generated from the gas turbine and the difference between the actual concentration of nitrogen oxides and the concentration calculated from the signal value Sig (Gs 2). In addition, the actual concentration of nitrogen oxide can be obtained using an analyzer (for example, a nitrogen oxide analyzer using chemiluminescence method (CLA)) whose measured value of the concentration of nitrogen oxide is hardly affected by the presence of components other than nitrogen oxide.

By correcting the concentration calculated using the signal value Sig (Gs2) by a correction amount that is a function of the concentration of carbon dioxide calculated from the fifth signal value Sig5, as shown in fig. 4, the calculated concentration of nitrogen oxides (graph shown by a solid line in fig. 4) and the actual concentration of nitrogen oxides (graph shown by a broken line in fig. 4) are extremely in agreement throughout the operation of the gas turbine (i.e., regardless of whether incomplete combustion occurs). In fig. 4, a graph indicated by a one-dot chain line shows the concentration of carbon dioxide. Fig. 4 is a diagram showing an example of a temporal change in the concentration of nitrogen oxides calculated by correcting the concentration calculated using the signal value Sig (Gs2) by the correction amount calculated from the fifth signal value, and a temporal change in the actual concentration of nitrogen oxides.

On the other hand, as a comparative example, in the case where the concentration calculated using the signal value Sig (Gs2) is not corrected, as shown in fig. 5, particularly in a period in which the concentration of carbon dioxide is small, that is, in a period in which incomplete combustion occurs due to low load operation of the gas turbine and carbon monoxide and unburned hydrocarbons are generated at a high concentration, the calculated concentration of nitrogen oxides (graph shown by a solid line in fig. 5) deviates from the actual concentration of nitrogen oxides. That is, the measurement result of the concentration of nitrogen oxides is affected depending on whether or not incomplete combustion occurs in the gas turbine. Fig. 5 is a diagram showing an example of a temporal change in concentration calculated using the signal value Sig (Gs2) and a temporal change in actual concentration of nitrogen oxides.

4. Other embodiments

While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications may be made without departing from the scope of the invention. In particular, the plurality of embodiments and modifications described in the present specification can be arbitrarily combined as needed.

(A) The analyzing apparatuses 100 and 200 can analyze two or more kinds of gases contained in the sample gas Gs. In this case, as described above, although the pneumatic detector is provided for each analysis object in the analysis device, the influence of the interference component common to the plurality of analysis objects can be measured by the common pneumatic detector.

(B) When a high-concentration gas is sealed in the sealed cell of the pneumatic detector (the fourth pneumatic detector 59 in the first and second embodiments), the calculation unit 7 may perform linearization processing on the signal output from the pneumatic detector.

(C) Instead of the optical branching member 51, the measurement light Lm may be propagated toward the first pneumatic detector 53 by providing a member having a tapered shape as the light condensing member 9.

(D) The analysis devices 100 and 200 may include a comparison cell and a light interruption mechanism. The comparison cell is a cell in which a gas such as nitrogen that does not absorb the measurement light Lm is sealed. The light interruption mechanism is a mechanism for switching whether or not the measurement light Lm is introduced into the measurement cell 1 and the comparison cell at the same time. Examples of such a photo-interrupter include a combination of a lighting light source for the measuring cell 1, a lighting light source for the comparison cell, and a chopper, and a combination of a scintillation light source for the measuring cell 1 and a scintillation light source for the comparison cell. The light source may be one that can simultaneously introduce the measurement light Lm into the measurement cell 1 and the comparison cell. The light interruption mechanism may alternatively introduce the measurement light Lm into the measurement cell 1 and the comparison cell. In this case, the arithmetic unit 7 analyzes the component gas to be analyzed based on the difference between the intensity of the measurement light Lm having passed through the measurement cell 1 and the intensity of the measurement light Lm having passed through the comparison cell. This can eliminate the background component contained in the measurement result of the measurement light Lm having passed through the measuring cell 1, thereby enabling analysis of the analysis gas with higher accuracy.

(E) As shown in fig. 6, (the inlet 1a of) the analyzer 100 or 200 may be connected to a sampling unit 101, and the sampling unit 101 may sample a gas including the sample gas Gs from a flue, a pipe, or the like and introduce the sample gas Gs into the measurement space Sp (i.e., the measurement cell 1) of the analyzer 100. Fig. 6 is a diagram showing a connection relationship between the sampling unit and the analyzer. The sampling unit 101 includes, for example: a probe 1011 for sampling gas flowing through a flue, a pipe, or the like; a collecting filter 1013 for collecting dust and the like contained in the sampled gas; and a pretreatment device 1015 for pretreating the sampled gas (for example, an electric cooler, a drainer, a tube pump, a mist trap for removing sulfuric acid mist and salt, etc.), and a device for removing Nitrogen Oxides (NO)_x) NOx converter formation for reduction to nitric oxide).

Industrial applicability

The present invention can be widely applied to a gas analyzer that analyzes a plurality of components contained in a sample gas.

Claims

1. A gas analyzer for analyzing a component contained in a sample gas, the gas analyzer comprising:

a measuring cell into which the sample gas is introduced;

a light source that radiates measurement light to the inside of the measurement cell;

A first pneumatic detector that measures an intensity of the measurement light absorbed by a first component gas contained in the sample gas in the measurement cell;

a second pneumatic detector that measures an intensity of the measurement light absorbed by a second component gas contained in the sample gas in the measurement cell;

a third pneumatic detector that measures an intensity of the measurement light absorbed by a third component gas in the measurement cell as an intensity of first passage measurement light, the third component gas being contained in the sample gas and having a light absorption characteristic for the measurement light at least partially overlapping with a light absorption characteristic for the measurement light by the first component gas and the second component gas, the first passage measurement light being the measurement light after passing through the second pneumatic detector; and

and a calculation unit that calculates information relating to the third component gas based on the intensity of the first passing measurement light measured by the third pneumatic detector.

2. The gas analyzer according to claim 1, wherein the calculation unit calculates the information on the first component gas based on the intensity of the measurement light measured by the first pneumatic detector and the intensity of the first passing measurement light measured by the third pneumatic detector.

3. The gas analyzer according to claim 1 or 2, wherein the first pneumatic detector includes a first sealed cell in which the first component gas is sealed and through which the measurement light passes.

4. The gas analyzer according to any one of claims 1 to 3, wherein the second pneumatic detector includes a second enclosure cell in which the second component gas is enclosed and through which the measurement light passes.

5. The gas analysis apparatus according to claim 4, wherein the third pneumatic detector includes a third sealed cell in which the second component gas is sealed.

6. The gas analysis apparatus according to claim 5, wherein the concentration of the second component gas in the second sealed-in cell is less than or equal to half the concentration of the second component gas in the third sealed-in cell.

7. The gas analysis device according to any one of claims 1 to 6, wherein the first component gas is sulfur dioxide, the second component gas is nitrogen oxide, and the third component gas is water vapor.

8. The gas analyzer according to any one of claims 1 to 7, further comprising a fourth pneumatic detector that measures an intensity of the measurement light absorbed by a fourth component gas, which is contained in the sample gas and has a light absorption characteristic for the measurement light that at least partially overlaps with a light absorption characteristic for the measurement light by the first component gas, as an intensity of a second passing measurement light that is the measurement light after passing through the first pneumatic detector.

9. The gas analysis device according to claim 8, wherein the calculation unit calculates the information on the first component gas based on the intensity of the measurement light measured by the first pneumatic detector, the intensity of the measurement light measured by the second pneumatic detector, the intensity of the first passage measurement light measured by the third pneumatic detector, and the intensity of the second passage measurement light measured by the fourth pneumatic detector.

10. The gas analysis apparatus according to claim 8 or 9, wherein the fourth component gas is methane.