Detection device and detection method

Abstract

This detection device (100) comprises a first gas cell (1), a first adsorbent (2), a first stimulation unit (3), a first light source (4), a first detector (5), and a measurement unit (102). A gas is introduced into the first gas cell (1). The first adsorbent (2) is filled into and disposed in the first gas cell (1) such that a first non-filled space (19) is formed inside of the first gas cell (1), and adsorbs a first target component in the gas. The first non-filled space (19) is a space not filled with the first adsorbent. The first stimulation unit (3) applies a stimulus to the first adsorbent (2) so as to desorb the first target component into the first non-filled space (19). The first light source (4) radiates light toward the first non-filled space (19). The first detector (5) detects light emitted from the first gas cell (1). The measurement unit (102) measures the first target component on the basis of the output of the first detector (5).

Description

Detection device and detection method

[0001] The present disclosure relates to detection devices and methods, and more particularly to gas detection devices and methods.

[0002] Techniques for detecting target components in a gas based on light absorption caused by passing light through the gas are known. Examples of such techniques include cavity ring-down spectroscopy, in which light is accumulated in a resonator (cavity) and then the light input to the resonator is blocked, a ring-down signal generated by the blocking is detected by a detector, and the target component is detected based on the ring-down signal. U.S. Pat. No. 1,149,916 (Patent Document 1) discloses a spectroscopic system in which a thermal desorption tube containing an adsorbent capable of desorbing target compounds in a gas by heating is provided in front of the ring-down cavity. In this spectroscopic system, the target compound can be concentrated in the thermal desorption tube and then sent to the ring-down cavity for detection.

[0003] U.S. Pat. No. 1,149,916

[0004] However, in the spectroscopic system of Patent Document 1, the thermal desorption tube and the ring-down cavity are connected by piping, which creates a dead volume and dilutes the target compound concentrated by the adsorbent. This dilution reduces the detection sensitivity of the target component. Furthermore, in the spectroscopic system of Patent Document 1, the thermal desorption tube and the ring-down cavity are connected by piping, which requires time for gas transport and increases the measurement time. This is particularly problematic when measuring low-concentration gases in a short measurement cycle.

[0005] The present disclosure has been made to solve such problems, and its purpose is to provide a detection device that can detect a target component in a gas in a short time and with high sensitivity.

[0006] A first aspect of the present invention is a detection device including a first gas cell, a first adsorbent, a first stimulation unit, a first light source, a first detector, and a measurement unit. Gas is introduced into the first gas cell. The first adsorbent is filled and arranged to form a first non-filled space inside the first gas cell, and adsorbs a first target component in the gas. The first non-filled space is a space not filled with the first adsorbent. The first stimulation unit applies a stimulation to the first adsorbent to desorb the first target component into the first non-filled space. The first light source irradiates light toward the first non-filled space. The first detector detects the light emitted from the first gas cell. The measurement unit detects the first target component based on the output of the first detector.

[0007] A second aspect of the present invention is a detection method comprising the steps of introducing a gas from which detection of a target component is desired into a gas cell filled with an adsorbent that adsorbs a target component so as to form an unfilled space therein. The unfilled space is a space that is not filled with the adsorbent. The detection method further comprises the steps of applying a stimulus to the adsorbent to desorb the target component into the unfilled space, irradiating the unfilled space with light, detecting the light emitted from the gas cell with a detector, and measuring the target component based on the output from the detector.

[0008] According to the present disclosure, it is possible to provide a detection device that can detect a target component in a gas in a short time and with high sensitivity.

[0009] FIG. 1 is a schematic diagram showing the configuration of a detection device according to embodiment 1. FIG. 2 is a flowchart showing a detection process for a target component in a gas. FIG. 3 is a diagram showing one stage of detection of a target component in a gas. FIG. 4 is a diagram showing one stage of detection of a target component in a gas. FIG. 5 is a diagram showing one stage of detection of a target component in a gas. FIG. 6 is a diagram showing one stage of detection of a target component in a gas. FIG. 7 is a schematic diagram showing the configuration of a detection device according to modified example 1. FIG. 8 is a schematic diagram showing the configuration of a detection device according to modified example 2. FIG. 9 is a schematic diagram showing the configuration of a detection device according to modified example 3. FIG. 10 is a schematic diagram showing the configuration of a detection device according to modified example 4. FIG. 11 is a diagram explaining the configuration of a detection device according to embodiment 2. FIG. 12 is a diagram explaining the structure of a gas cell according to embodiment 2 when viewed through from the light source side. FIG. 13 is a table for explaining the settings of a detection device according to embodiment 2.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0011] 1. Configuration of the Detection Apparatus FIG. 1 is a schematic diagram showing the configuration of a detection apparatus 100 according to an embodiment of the present invention. The detection apparatus 100 detects a target component in a gas introduced from the outside. In one embodiment, the detection apparatus 100 measures the concentration of the target component in the gas. In another embodiment, the detection apparatus 100 is used to detect the presence or absence of the target component in the gas. Note that, in this specification, the target component refers to a substance that is the target of detection by the detection apparatus 100.

[0012] 1, a portion of the gas in the gas pipe 8 is introduced into the detection device 100 through a pipe 63. The detection device 100 includes a detection unit 101 and a control device .

[0013] The detection unit 101 includes a gas cell 1, an adsorbent 2, a stimulating unit 3, a light source 4, a detector 5, valves 61 and 62, and pipes 63 and 64. The gas cell 1, the adsorbent 2, the stimulating unit 3, the light source 4, and the detector 5 correspond to an example of a "first gas cell," a "first adsorbent," a "first stimulating unit," a "first light source," and a "first stimulating unit," respectively. The target component adsorbed by the adsorbent 2 corresponds to an example of a "first target component."

[0014] The gas pipe 8 is a pipe through which a gas to be tested, which may contain a target component, passes. In one embodiment, the test gas contains a base gas, which is the main component, and a target component to be detected. The base gas is, for example, carbon dioxide. However, the base gas may contain multiple types of gases. In Figure 1 and subsequent figures, the target component in the gas cell 1 is represented by a figure 9.

[0015] The pipe 63 connects the gas pipe 8 and the gas cell 1. The pipe 63 is a pipe for introducing a portion of the gas in the gas pipe 8 into the gas cell 1. The pipe 63 is provided with a valve 61. The valve 61 adjusts the introduction of gas into the gas cell 1. The valve 61 corresponds to one embodiment of an "introduction opening / closing unit." The pipe 64 is a pipe for discharging gas discharged from the gas cell 1 to the outside. In one embodiment, one end of the pipe 64 is connected to the gas cell 1, and the other end is open to the outside air. The pipe 64 is provided with a valve 62. The valve 62 processing unit adjusts the discharge of gas from the gas cell 1. The valve 62 corresponds to one embodiment of an "exhaust opening / closing unit." With the above configuration, the gas cell 1 has different holes for introducing and discharging gas, and the introduction and discharge of gas can be easily controlled. Therefore, by passing gas through the gas cell 1, it is easy to efficiently adsorb the target component to the adsorbent 2.

[0016] 1, the direction in which gas flows in the pipes 63 and 64 is defined as the positive X-axis direction, the direction parallel to the central axis AX of the light transmitted through the gas cell 1 is defined as the negative Z-axis direction, and the direction perpendicular to the XZ plane is defined as the Y-axis. Note that the direction in which gas flows in the pipes 63 and 64 and the central axis AX of the light transmitted through the gas cell 1 do not necessarily need to be perpendicular to each other, and the negative Z-axis direction does not necessarily need to be the direction of gravity.

[0017] A gas is introduced into the gas cell 1 from a gas pipe 8. The adsorbent 2 is filled and arranged in the gas cell 1 so as to form an unfilled space 19. When the gas introduced into the gas cell 1 contains a target component, the target component is adsorbed by the adsorbent 2.

[0018] More specifically, the gas cell 1 includes a pair of optical windows 131 and 132 and a housing 14. The housing 14 has an inlet 11 and an outlet 12 formed therein.

[0019] The inlet 11 is connected to a pipe 63. In one embodiment, when the valve 61 is open, gas from the gas pipe 8 is introduced into the gas cell 1 through the inlet 11.

[0020] The exhaust port 12 is connected to a pipe 64. In one embodiment, when the valve 62 is opened, the gas in the gas cell 1 is exhausted from the exhaust port 12.

[0021] The housing 14 supports the entire structure of the gas cell 1. Therefore, the housing 14 is formed of a material having sufficient rigidity to support the entire structure of the gas cell 1. The housing 14 includes, for example, a metal or a ceramic. As will be described later, when the adsorbent 2 has the property of desorbing the target component by applying heat, the housing 14 is preferably formed of a material with high thermal conductivity. The material with high thermal conductivity is, for example, a metal or a ceramic with high thermal conductivity.

[0022] The pair of optical windows 131 and 132 are window members respectively fitted into two opposing hole portions formed in the housing 14 .

[0023] The adsorbent 2 is filled and arranged to form an unfilled space 19 inside the gas cell 1. In this specification, the unfilled space 19 is a space inside the gas cell 1 that is not filled with the adsorbent 2. By filling and arranging the adsorbent 2 to form the unfilled space 19 inside the gas cell 1, an optical path can be formed in the unfilled space 19. In the example of FIG. 1 , the unfilled space 19 is a space between the optical windows 131 and 132 inside the housing 14 where the adsorbent 2 is not arranged. An optical path 45 is formed in the unfilled space 19. The unfilled space 19 corresponds to one example of a "first unfilled space."

[0024] The light source 4 irradiates light into the gas cell 1. More specifically, the light source 4 is disposed at a position where it irradiates light toward the non-filled space 19, and irradiates the light toward the non-filled space 19. The light source 4 is, for example, a laser light source. In the example of FIG. 1 , the light emitted from the light source 4 is reflected by one or more mirrors (not shown), passes through an optical window 131, and is irradiated toward the non-filled space 19. However, the light emitted from the light source 4 may be configured to be irradiated directly toward the non-filled space 19 without passing through a mirror.

[0025] The detector 5 is disposed at a position where it detects light emitted from the gas cell 1, and is a detector that detects the light emitted from the gas cell 1. The detector 5 detects a target component in the gas based on light that has passed through the gas desorbed into the non-filled space 19 in the gas cell 1. The detector 5 is, for example, a photodetector such as a photodiode or an image sensor. In the example of FIG. 1 , the light emitted from the non-filled space 19 passes through the optical window 132 and enters the detector 5. A detection signal indicating the detection result of the detector 5 is transmitted to the control device 102.

[0026] By arranging the light source 4 and the detector 5 as described above, an optical path 45 is formed in the unfilled space 19 through which light passes from the light source 4 to the detector 5 .

[0027] Preferably, the gas cell 1 has an optical resonator structure. The optical resonator structure, also known as a multi-reflection structure or multi-path optical system, confines light between facing mirrors and causes the light to travel back and forth multiple times. For example, the optical windows 131 and 132 are mirrors that reflect most of the received light. This allows the light to travel back and forth multiple times in the non-filled space 19, thereby amplifying the distance the light travels through the gas (effective optical path length). The detector 5 detects light leaking through the optical window 132 as detection light. This configuration allows the optical absorption of the target component in the non-filled space 19 to be amplified and detected. This improves the detection sensitivity of the target component.

[0028] When the gas cell 1 does not have an optical resonator structure, the optical windows 131 and 132 can be made of a window material containing glass, resin, or the like that transmits most of the light.

[0029] The adsorbent 2 adsorbs the target component in the gas. This allows the concentration of the target component in the gas cell 1 to be increased (concentrated). The adsorbent 2 has the property of desorbing the adsorbed target component when a predetermined stimulus is applied. This allows the gas cell 1 to be filled with gas containing the concentrated target component. Therefore, even if the target component is present in only a trace amount in the gas pipe 8, the concentrated target component can be detected in the gas cell 1. In particular, by disposing the adsorbent 2 in the gas cell 1, the volume of the space from the adsorbent 2 to the detection position (non-filled space 19) of the desorbed target component can be minimized. This prevents the concentrated target component from being diluted, enabling highly sensitive detection of the target component. Furthermore, the transport path from the adsorbent 2 to the detection position (non-filled space 19) of the desorbed target component can be minimized, enabling the target component to be detected in a short time (described in detail below).

[0030] In one embodiment, the adsorbent 2 is Mg-gallate that adsorbs sulfur dioxide, and the detection device 100 detects sulfur dioxide in carbon dioxide. In another embodiment, the adsorbent 2 is an fcu-MOF that adsorbs ammonia, and the detection device 100 detects ammonia in carbon dioxide. The adsorbent 2 is disposed inside the gas cell 1. In one embodiment, the adsorbent 2 is supported on a carrier and is supported inside the gas cell 1. For example, the adsorbent 2 is disposed so as to cover the surface of the carrier, and in FIG. 1, the carrier is included in the portion indicated by reference numeral 2. In another embodiment, the adsorbent 2 is supported on an inner wall 141 of the gas cell 1. In this case, the inner wall 141 is the carrier for the adsorbent 2. The carrier for the adsorbent 2 includes, for example, a metal or a ceramic.

[0031] In the example of FIG. 1 , the adsorbent 2 includes an adsorbent 21 arranged on the inlet 11 side and an adsorbent 22 arranged on the outlet 12 side. This arrangement allows all of the gas flowing into the gas cell 1 to pass through the adsorbent 21, and all of the gas exhausted from the gas cell 1 to pass through the adsorbent 22. This makes it easier for the target component to be adsorbed by the adsorbent than when only one of the adsorbents 21 and 22 is included in the gas cell 1. Furthermore, this arrangement makes it easier for the target component to be adsorbed by the adsorbent than when the adsorbents 21 and 22 are arranged parallel to the gas flow direction in the gas cell 1 at a distance from each other. By making it easier for the target component to be adsorbed by the adsorbent, the amount of the target component adsorbed by the adsorbent per unit time increases. This enables detection in a shorter time and / or with higher sensitivity.

[0032] The adsorbent 2 preferably has a honeycomb structure or a fin structure. In one embodiment, the adsorbent 2 is supported on the surface of a carrier having a honeycomb structure or a fin structure. This configuration increases the surface area of ​​the adsorbent 2, making it easy to increase the amount of target components liberated in the gas that are adsorbed. Therefore, the concentration of the target component in the gas cell 1 can be further increased. More preferably, the gas in the gas cell 1 is arranged so that it passes through at least a portion of the honeycomb structure or the fin structure. This further facilitates adsorption of the target component in the gas to the adsorbent 2. Therefore, the concentration of the target component in the gas cell 1 can be further increased. In the example of FIG. 1 , for example, the adsorbents 21 and 22 are arranged so that the holes in the honeycomb structure or the gaps in the fin structure are aligned parallel to the X-axis. This allows the gas introduced through the inlet 11 to pass through the holes in the honeycomb structure or the gaps in the fin structure of the adsorbent 21 before being introduced into the unfilled space 19. Furthermore, the gas introduced into the non-filled space 19 can be passed through the holes in the honeycomb structure of the adsorbent 22 or the gaps in the fin structure, and then discharged from the outlet 12. This configuration makes it easier for the target component to be adsorbed onto the adsorbent 2. This allows for detection in a shorter time and / or with higher sensitivity.

[0033] Preferably, the adsorbent 2 is configured to be detachable from the gas cell 1. This makes it easy to replace the adsorbent 2. Therefore, it is easy to replace the adsorbent 2 that has deteriorated due to repeated use. Furthermore, by replacing the adsorbent 2 with one that adsorbs a different target component, it is also possible to reconfigure the gas cell 1 to detect a different target component.

[0034] The stimulating unit 3 applies a stimulus to the adsorbent 2 to desorb the target component into the non-filled space 19. The type of stimulus applied by the stimulating unit 3 to desorb the target component depends on the type of adsorbent 2. According to one embodiment, the stimulating unit 3 desorbs the target component from the adsorbent 2 by microwave heating or heater heating of the adsorbent 2. In this manner, desorption of the target component from the adsorbent 2 and adsorption of the target component to the adsorbent 2 can be easily controlled. Preferably, the stimulating unit 3 heats the adsorbent 2 so as to generate a temperature gradient within the gas cell 1. In the example of FIG. 1 , by heating the adsorbents 21 and 22 to the same set temperature, the temperature in the center of the non-filled space 19 is lower than that in the vicinity of the adsorbents 21 and 22. In another example, the set temperature of the adsorbent 21 on the inlet 11 side may be higher than the set temperature of the adsorbent 22 on the outlet 12 side, thereby making the temperature on the inlet 11 side higher and the temperature on the outlet 12 side lower. In this way, by generating a temperature gradient within the gas cell 1, convection occurs within the gas cell 1, promoting the diffusion of the desorbed target gas. As a combination of the stimulation unit 3 and the adsorbent 2, a combination may be used in which the stimulation unit 3 applies a stimulus such as light or a magnetic field to the adsorbent 2, causing the adsorbent 2 to desorb the target component.

[0035] The control device 102 includes a processor 103 such as a CPU (Central Processing Unit) or FPGA (Field-Programmable Gate Array), a memory 104 such as a ROM (Read Only Memory) or RAM (Random Access Memory), and an input / output port (not shown).

[0036] The control device 102 controls the detection unit 101. The control device 102 corresponds to an embodiment of a "measurement unit" that measures the target component based on the output of the detector 5. Specifically, the control device 102 executes various data processing operations to calculate the concentration of the target component contained in the gas based on the detection signal from the detector 5.

[0037] The control device 102 may be configured by dividing it into two or more units for each function. For example, the control device 102 may be divided into a unit that controls each device and a unit that executes various data processing.

[0038] [2. Detection Flow] Fig. 2 is a flowchart showing the detection process for a target component in a gas. Figs. 3 to 6 are diagrams showing the stages of detection of a target component in a gas. The process in Fig. 2 will be explained below with appropriate reference to Figs. 3 to 6. The process in Fig. 2 is performed by processor 103.

[0039] Referring to FIG. 2 , in ST01, the processor 103 introduces a gas from which detection of a target component is desired into the gas cell 1, in which the adsorbent 2 is filled and arranged to form an unfilled space 19. In one embodiment, in ST01, the processor 103 opens the valves 61 and 62 before and after the gas cell, thereby introducing gas from the gas pipe 8 into the gas cell 1 and discharging the gas that has passed through the gas cell 1 to the outside. This causes the target component to be adsorbed onto the adsorbent 2 arranged inside the gas cell 1 (see FIG. 3 ). Continuing to introduce the gas into the gas cell 1 increases the amount of the target component adsorbed onto the adsorbent 2. As described above, the target component is concentrated in the gas cell 1 by accumulating the amount of adsorption of the target component (see FIG. 4 ).

[0040] In ST02, the processor 103 stops the introduction of gas into the gas cell 1 after a predetermined time has elapsed since the start of the gas introduction. The predetermined time is preferably shorter than the breakthrough time pre-designed based on the specifications of the gas cell 1. This design prevents the target component from saturating, allowing the concentration to be measured appropriately. Furthermore, the target component is not contained in the gas discharged from the gas cell 1. This prevents the target component from polluting the outside air, even if it is a harmful substance. The predetermined time for introducing the gas into the gas cell 1 may be determined based on an estimated concentration of the target component in the gas cell 1. For example, if the gas in the gas pipe 8 contains a target component, the predetermined time for introducing the gas may be the time at which the target component is expected to reach a detectable concentration in the detector 5.

[0041] In one embodiment, in ST02, the processor 103 closes the valves 61 and 62 (see FIG. 5 ). This makes the inside of the gas cell 1 a closed space. Therefore, concentration of the target component in the gas cell 1 is stopped. Even if the target component is desorbed from the adsorbent 2, it will not leak out of the gas cell 1.

[0042] In ST03, the processor 103 applies a stimulus to the adsorbent 2 using the stimulating unit 3. This causes the target component to be desorbed from the adsorbent 2 into the non-filled space 19. The desorbed target component diffuses into the non-filled space 19 (see FIG. 6 ). In the example of FIG. 6 , the target component adsorbed to the adsorbent 2 is indicated by a figure 91, and the target component in the gas desorbed from the adsorbent 2 is indicated by a figure 92.

[0043] After stimulating the adsorbent 2 at a predetermined intensity for a predetermined time, in ST04, the processor 103 controls the light source 4 to irradiate light toward the unfilled space 19 in the gas cell 1. Preferably, the intensity and time of the stimulus to the adsorbent 2 before irradiating the gas cell 1 with light are set so that the target component is sufficiently desorbed from the adsorbent 2 and the gas cell 1 is in a steady state before the light is irradiated.

[0044] In ST05, the processor 103 detects the emitted light from the gas cell 1. In the example of FIG. 6 , the detector 5 detects the transmitted light emitted from the gas cell 1. The processor 103 receives a detection signal from the detector 5. More specifically, since the target component in the unfilled space 19 absorbs a predetermined light component, the transmitted light attenuates the light component from the incident light by an amount corresponding to the concentration of the target component. The processor 103 receives a detection signal indicating the attenuation. Note that in ST05, the detector 5 may be configured to detect the reflected light emitted from the gas cell 1. More specifically, the detector 5 may detect scattered light due to Raman scattering and detect light components contained in the scattered light.

[0045] In ST06 and ST07, the processor 103 measures the target component based on the output from the detector 5. An example of ST06 and ST07 will be described below.

[0046] In ST06, the processor 103 measures, from the detection signal, the concentration of the target component in the gas in the gas cell 1. In the example of Fig. 6, the concentration of the target component in the gas in the unfilled space 19 is measured as the concentration of the target component in the gas cell 1.

[0047] In ST07, the processor 103 calculates the concentration of the target component contained in the gas in the gas pipe 8 from the concentration of the target component in the gas cell 1. For example, the processor 103 calculates the concentration of the target component in the gas in the gas pipe 8 based on the concentration of the target component in the gas cell 1 measured in ST06 and the volume of gas passed through the gas cell 1. For example, if the time during which the gas was introduced into the gas cell 1 is shorter than the breakthrough time and it is considered that all of the target component has been desorbed from the adsorbent 2 due to the stimulation of the stimulation unit 3, the concentration of the target component in the gas in the gas pipe 8 is the value obtained by dividing the amount of the target component in the gas cell 1 by the volume of the gas passed through the gas cell 1. The amount of the target component in the gas cell 1 is the product of the volume of the gas cell and the concentration in the gas cell. The volume of the gas passed through the gas cell 1 is, for example, the product of the flow rate of the gas in the gas cell 1 (the volume of gas moved per unit time) and the length of time the gas was introduced into the gas cell 1. The flow rate of the gas in the gas cell 1 is determined, for example, by providing a flow rate sensor (not shown) in the pipe 63 and based on the detection value of the flow rate sensor.

[0048] In ST08, the processor 103 discharges the gas in which the target component is concentrated from the gas cell 1. In one embodiment, in ST08, the processor 103 opens the valves 61 and 62 before and after the gas cell 1. This allows gas to be introduced into the gas cell 1 from the gas pipe 8, and the gas in which the target component is concentrated from the gas cell 1 is discharged.

[0049] After a predetermined time has elapsed since the discharge of gas from the gas cell 1 began in ST08, the processor 103 stops stimulating the adsorbent 2 by the stimulating unit 3 in ST09. The predetermined time is set to be longer than the time it is estimated that the gas containing the concentrated target component in the gas cell 1 has been discharged. For example, in ST09, the stimulation by the stimulating unit 3 may be stopped after transmitting light from the light source 4 and confirming that the concentration of the target component detected by the detector 5 is sufficiently low. More specifically, the stimulation may be stopped several seconds after the concentration of the target component in the gas cell 1 falls below the detection limit. Steps ST03 to ST09 constitute one cycle of target component detection.

[0050] In ST10, processor 103 determines whether a condition for ending detection of the target component is met. One example of the condition is receiving a user instruction to end detection. Another example of the condition is completion of detection for a predetermined number of cycles.

[0051] If the termination condition is not met (NO in ST10), processor 103 returns the process to ST01. Then, the next detection cycle is performed. Note that in ST01 of the second or subsequent cycle, if valves 61 and 62 have already been opened in ST08 of the previous cycle, processor 103 only needs to maintain valves 61 and 62 in the open state.

[0052] On the other hand, if the termination condition is met (YES in ST10), the processor 103 terminates the process.

[0053] 1 to 6, the adsorbent 2 is filled and arranged in the gas cell 1 so as to form an unfilled space 19, so that the target component concentrated by the adsorbent 2 can be detected without dilution. For example, in the spectroscopic system of Patent Document 1, the test gas is introduced into a thermal desorption tube to concentrate the target compound, and the gas in which the target compound is concentrated is detected by a laser. As a result, the spectroscopic system of Patent Document 1 can detect the target component with higher sensitivity than a device without a concentration section.

[0054] However, in the spectroscopic system of Patent Document 1, the thermal desorption tube and the ring-down cavity are connected by piping, resulting in a dead volume. In this specification, the term "dead volume" refers to the volume of the portion from the portion where the target component is concentrated to the portion where it is detected, where the concentrated target component is diluted before being detected (for example, the portion including the piping in Patent Document 1). In the spectroscopic system of Patent Document 1, the concentrated target component is diluted by the dead volume. The target component is also diluted if it adheres to the wall surface of the gas piping 8, etc.

[0055] On the other hand, in the detection device 100, the dead volume can be minimized by integrating the portion where the adsorbent 2 is placed with the gas cell 1. This makes it possible to suppress dilution of the desorbed gas, thereby enabling detection of the target component with higher sensitivity.

[0056] Furthermore, the detection device 100 can measure the target component desorbed from the adsorbent 2 in the gas cell 1 in situ. For example, the spectroscopic system of Patent Document 1 had a problem in that the measurement time was long because it took time to transport the target component desorbed from the thermal desorption tube to the link town cavity through a pipe. However, in the detection device 100, the adsorbent 2 that adsorbs the target component and the unfilled space 19 where the target component is detected are adjacent to each other, thereby reducing the time required to transport the desorbed gas to the gas cell. This allows the detection device 100 to detect the target component in a short time. Therefore, the detection device 100 is suitable for continuously monitoring the presence and / or concentration of the target component in the gas pipe 8. As described above, the detection device 100 and detection method according to this embodiment can be said to be a detection device and detection method capable of detecting a target component in a gas in a short time and with high sensitivity. Therefore, low concentrations of the target component can be detected in a short detection cycle.

[0057] 7 to 10 show first to fourth modifications of the detection device 100 according to the above embodiment.

[0058] FIG. 7 is a schematic diagram showing the configuration of a detection device according to Modification 1. The detection unit 101A in FIG. 7 includes a cooler 71 in addition to the configuration of the detection unit 101 in FIG. 1 . The cooler 71 cools the adsorbent 2 heated by the stimulation unit 3 after the target component concentration in the gas cell 1 is measured. This shortens the time until the adsorbent 2 is again able to adsorb the target component. Therefore, the time required for one detection cycle can be shortened, thereby speeding up the detection cycle. In the example in FIG. 7 , the cooler 71 indirectly cools the adsorbent 2 by cooling the housing 14F, which has high thermal conductivity; however, the cooler 71 may also cool the adsorbent 2 directly.

[0059] FIG. 8 is a diagram showing the configuration of a detection device according to Modification 2. The detection unit 101B of FIG. 7 includes light sources 721 and 722, detectors 723 and 724, and optical windows 725-728 in addition to the configuration of the detection unit 101 of FIG. 1 . The light sources 721 and 722 irradiate light onto the adsorbents 21 and 22, respectively. The detectors 723 and 724 detect target components adsorbed to the adsorbents 21 and 22, respectively, based on the light emitted from the adsorbents 21 and 22, respectively. For example, the detectors 723 and 724 detect transmitted light or scattered light from the adsorbents 21 and 22, respectively. The optical windows 725 and 726 are disposed between the light sources 721 and 722 and the adsorbents 21 and 22, respectively. The optical windows 727 and 728 are disposed between the adsorbents 21 and 22 and the detectors 723 and 724, respectively. The light emitted from the light sources 721 and 722 passes through optical windows 725 and 726 and enters the adsorbents 21 and 22, respectively. The light emitted from the adsorbents 21 and 22 passes through optical windows 727 and 728, respectively, and enters the detector 5.

[0060] The detection signals of the emitted light from the detectors 723 and 724 are transmitted to the control device 102, and the control device 102 detects the target component adsorbed to the adsorbents 21 and 22 based on the detection signals. The control device 102 measures the concentration of the target component based on, for example, the spectral change of the transmitted light relative to the incident light or the spectral change of the reflected light relative to the incident light. In the detection device according to the second modification, even if a portion of the target component remains in the adsorbents 21 and 22 after the stimulation unit 3 applies a stimulus to the adsorbents 21 and 22, the concentration of the remaining target component can also be measured. Therefore, the concentration of the target component in the gas cell 1 can be determined more accurately than when only the concentration of the target component in the gas is measured. Therefore, the concentration of the target component in the gas pipe 8 can be determined with higher accuracy. Therefore, the detection unit 101B allows for more accurate monitoring of the target component.

[0061] FIG. 9 is a diagram showing the configuration of a detection device according to Modification 3. The detection unit 101C of FIG. 9 includes a separation unit 73 in addition to the configuration of the detection unit 101 of FIG. 1 . The separation unit 73 is provided upstream of the gas cell 1. In the example of FIG. 9 , the separation unit 73 is installed in the pipe 63 between the valve 61 and the gas cell 1. The separation unit 73 separates a specific component from the gas introduced from the gas pipe 8. This allows the specific component to be removed before the gas is introduced into the gas cell 1. The separation unit 73 includes, for example, an adsorbent that adsorbs the specific component. The specific component is a component contained in the gas in the gas pipe 8 that is different from the target component. The specific component is, for example, a substance that is unnecessary or interferes with the measurement of the target component. Therefore, the detection unit 101C can accurately measure the target component even when the gas in the gas pipe 8 contains a substance that is unnecessary or interferes with the measurement of the target component.

[0062] Fig. 10 is a diagram showing the configuration of a detection device according to Modification 4. The detection device according to Modification 4 described in Fig. 10 includes a detection unit 101E in addition to a detection unit 101D having a configuration similar to that of detection unit 101 in Fig. 1 .

[0063] The detection unit 101E includes a gas cell 1E, an adsorbent 2E, a stimulating unit 3E, a light source 4E, a detector 5E, valves 61E and 62E, and pipes 63E and 64E. The gas cell 1E, the adsorbent 2E, the stimulating unit 3E, the light source 4E, the detector 5E, and the non-filled space 19E correspond to examples of a "second gas cell," a "second adsorbent," a "second stimulating unit," a "second light source," a "second stimulating unit," and a "second non-filled space," respectively. The target component adsorbed by the adsorbent 2E (shown in figure 9E) corresponds to an example of a "second target component."

[0064] The target component adsorbed by the adsorbent 2E is different from the target component adsorbed by the adsorbent 2. Therefore, the detection unit 101E can detect a target component different from that detected by the detection unit 101. As a result, the detection device according to the fourth modification can simultaneously monitor a plurality of target components in the gas pipe 8.

[0065] 11 to 13, a detection device according to embodiment 2 will be described. In the detection device according to embodiment 2, the configuration of a detection unit 101F differs from the configuration of the detection unit 101 of the detection device 100 according to embodiment 1.

[0066] Fig. 11 is a diagram illustrating the configuration of the detection device according to embodiment 2. In Fig. 11, the light source 4 and the detector 5 of the detection unit 101F are omitted, and the configuration of the gas cell 1F is shown in a cross-sectional view. Fig. 12 is a diagram illustrating the structure of the gas cell 1F when viewed through from the light source 4 side (the positive Z-axis direction side).

[0067] The detection unit 101F differs from the detection unit 101 in the configuration of the gas cell 1F and the configuration of the adsorbent 2F. The detection unit 101F also differs from the detection unit 101 in that the detection unit 101F includes heat insulating materials 65F and 66F in front and behind the gas cell 1F. The gas flows in Figures 11 and 12 are indicated by arrows AR1 to AR4.

[0068] The heat insulating materials 65F and 66F insulate the gas cell 1F from the outside of the gas cell 1F. This prevents heat conduction to or from the outside even when the gas cell 1F is at a higher or lower temperature than the outside.

[0069] The gas cell 1F includes a pair of optical windows 131F and 132F and a housing 14F. A generally cylindrical inner hole 15F is formed in the housing 14F. An adsorbent 2F is filled and arranged in the inner hole 15F so as to form an unfilled space 19F.

[0070] In one embodiment, the adsorbent 2F is supported on a carrier and is supported in the gas cell 1F. For example, the adsorbent 2F is arranged so as to cover the surface of the carrier, and in Fig. 11, the carrier is included in the portion indicated by the symbol 2F.

[0071] The adsorbent 2F has a cylindrical outer shape. However, the internal structure of the adsorbent 2 preferably has a honeycomb structure or a fin structure, with gaps arranged along the gas flow direction (the direction indicated by arrow AR2). This makes it easy for the gas introduced from the inlet 11F (see arrow AR1) to pass through the holes in the honeycomb structure or the gaps in the fin structure (see arrow AR2).

[0072] The inner hole 15F has a recess formed near the center along the Z axis. A space 16F is formed between the recess and the adsorbent 2F. This allows gas that has passed through the adsorbent 2F as indicated by arrow AR2 to pass through the space 16F as indicated by arrow AR3 and then be discharged from the outlet 12F.

[0073] As described above, the structures of the gas cell 1F and the adsorbent 2F of the second embodiment allow gas to pass through the entire adsorbent 2F, thereby promoting adsorption of the target component to the adsorbent 2F, thereby increasing the concentration of the target component in the gas cell 1F.

[0074] More specifically, the amount of the target component adsorbed to the adsorbent increases as the contact area between the gas and the adsorbent increases and as the contact time increases, unless the adsorption amount is saturated. Naturally, the amount of the target component adsorbed also increases as the amount of gas passing through the adsorbent increases. In the second embodiment, in addition to the structure ( FIG. 11 ) that increases the opportunities for the gas to pass through the adsorbent, the concentration of the target component in the gas cell 1F is also increased by setting the internal volume (capacity) of the gas cell 1, the volume of the adsorbent, the gas flow rate, the time for concentrating the target component in the gas, and the like.

[0075] 13 is a table for explaining the settings of the detection device according to the second embodiment. In the second embodiment, by reducing the volume of the gas cell 1F, it is easy to concentrate the target component to the concentration required for detection, and measurement can be performed in a short time. It is preferable that the volume of the gas cell 1F is calculated including the volume of the dead volume in the valve, etc. The volume of the gas cell 1F is, for example, 1000 mm ３ In the small gas cell 1F, a large amount of adsorbent 2F is provided so as to fill the space except for the non-filled space 19F for transmitting light and the space 16F for diffusing gas. The volume of the adsorbent 2F is, for example, 500 mm ３ With this structure, the concentration of the target component in the gas cell 1F can be further increased in a short time by increasing the volume ratio between the interior of the gas cell 1F and the adsorbent 2F. The volume ratio is, for example, about 0.5.

[0076] The flow rate of the gas passing through the gas cell 1F (gas flow rate) is set so that the gas passes through the adsorbent 2 at an appropriate speed in the gas cell 1. For example, the gas flow rate is 1.5 L / mm.

[0077] Furthermore, by heating and cooling the temperature inside the gas cell 1F using the stimulation unit 3F and the cooler 71F, the temperature inside the gas cell 1F can be quickly switched from high to low and vice versa. The stimulation unit 3F is, for example, a heater and / or a Peltier element. The cooler 71F is, for example, a Peltier element. This allows a set temperature to be set, for example, above room temperature and below 200°C, and the temperature inside the gas cell 1F can be adjusted to above room temperature and below 200°C. In one embodiment, the set temperature is set to two levels: a temperature at which the target component is easily adsorbed onto the adsorbent 2F (adsorption temperature), and a temperature at which the target component is easily desorbed from the adsorbent 2F (desorption temperature). The adsorption temperature and desorption temperature are, for example, room temperature and 200°C, respectively. The temperature is raised from the adsorption temperature to the desorption temperature in, for example, 2 seconds. The cooling from the desorption temperature to the adsorption temperature is, for example, 8 seconds.

[0078] The pressure (internal pressure) in the gas cell 1F is set so as not to interfere with the adsorption process of the target component to the adsorbent 2F, the temperature increase process in the gas cell 1, and the desorption process of the target component from the adsorbent 2F, and / or so as to be a pressure suitable for each process. For example, the internal pressure during adsorption is 200 kPa, the internal pressure during temperature increase is 315 kPa, and the internal pressure during desorption is 315 kPa.

[0079] The configuration and settings of the gas cell 1F as described above can shorten the time required to concentrate the target component in the gas (concentration time) and the time required to measure the concentration of the target component in the gas. The concentration time is the time required for the target component in the gas to be adsorbed by the adsorbent 2F. The concentration time is, for example, 40 seconds, and the measurement time is, for example, 40 seconds.

[0080] Examples of target components to be detected include, but are not limited to, NH ３ , NO, N ２ 0, NO ３ , HCN, H ２ S, SO２ , S.O. ３ The gas cell 1F is capable of detecting these target components in a short time with high sensitivity. The lower detection limit is, for example, 10 ppb.

[0081] The optical path length D1 in the gas cell 1F is set to a length sufficient for detection. The optical path length D1 is, for example, approximately 10.5 mm. In one embodiment, in the gas cell 1F, light incident through the optical window 131F passes through an area 763 sandwiched between dashed lines 761 and 762 and exits from the optical window 132F. The central axis of the area 763 is indicated by a dashed-dotted line AXF. The unfilled space 19F between the optical windows 131F and 132F may be configured to function as a resonator.

[0082] The numerical example in FIG. 13 is merely an example and may be modified as appropriate within the scope of the effects of this embodiment. The detection flow in the detection device according to the second embodiment is similar to the flowchart shown in FIG. 2 . In summary, in the second embodiment, the processor 103 opens the valves 61F and 62F to adsorb the target component to the adsorbent 2F. Next, the valves 61F and 62F are closed, and the target component is desorbed from the adsorbent 2 into the non-filled space 19F by the stimulating unit 3F. Then, the light source 4 irradiates the non-filled space 19F with light, thereby forming an optical path 45F. Based on the detection signal from the detector 5 that detects the light emitted from the gas cell 1F, the concentration of the target component in the gas cell 1F is calculated, and the concentration of the target component in the gas pipe 8 is calculated. Then, the valves 61F and 62F are opened to allow gas from the gas pipe 8 to flow, flushing the gas in which the target component has been concentrated from the adsorbent 2F out of the gas cell 1F. After the gas containing the concentrated target component is discharged from the gas cell 1F, stimulation of the adsorbent 2F by the stimulation unit 3F is stopped and / or cooling by the cooler 71F is started. When the adsorbent 2F returns to the state it was in before stimulation by the stimulation unit 3F, unless the user issues an instruction to end the measurement, the process proceeds to the adsorption process of the target component for the next measurement.

[0083] The detection device and detection method according to the above-described embodiments and modifications can detect trace amounts of a target component contained in a test gas with high sensitivity and in a short time. By measuring the concentration of a specific gas component contained in a test gas with high sensitivity using this technology, it is possible to analyze the ratio of gas components contained in a feed gas used in a chemical process and / or the state of a chemical reaction in the chemical process. More specifically, it is possible to analyze trace amounts of impurity gases contained in a feed gas at chemical plants and their research and development sites.

[0084] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0085] (Item 1) A detection device according to one aspect includes a first gas cell, a first adsorbent, a first stimulation unit, a first light source, a first detector, and a measurement unit. Gas is introduced into the first gas cell. The first adsorbent is filled and arranged to form a first non-filled space inside the first gas cell, and adsorbs a first target component in the gas. The first non-filled space is a space that is not filled with the first adsorbent. The first stimulation unit applies a stimulation to the first adsorbent to desorb the first target component into the first non-filled space. The first light source irradiates light toward the first non-filled space. The first detector detects the light emitted from the first gas cell. The measurement unit detects the first target component based on the output of the first detector.

[0086] According to the detection device described in paragraph 1, by disposing the adsorbent in the gas cell, the volume of the space up to the detection position of the target component desorbed from the adsorbent can be minimized. This prevents the concentrated target component from being diluted, enabling highly sensitive detection of the target component. Furthermore, by minimizing the transport path from the target component desorbed from the adsorbent to the detection position, the target component can be detected in a short time. As described above, a detection device capable of detecting a target component in a gas in a short time and with high sensitivity can be provided.

[0087] (Item 2) The detection device described in item 1 further comprises an inlet opening / closing part that adjusts the introduction of gas into the first gas cell, and an outlet opening / closing part that adjusts the exhaust of gas from the first gas cell.

[0088] According to the detection device described in paragraph 2, the gas cell has different holes for introducing and discharging gas, and the introduction and discharge of gas can be easily controlled. Therefore, by passing gas through the gas cell, it is easy to efficiently adsorb the target component onto the adsorbent.

[0089] (Item 3) In the detection device according to Items 1 or 2, the first adsorbent has a honeycomb structure or a fin structure, and is arranged so that the gas in the first gas cell passes through the honeycomb structure or the fin structure.

[0090] According to the detection device described in paragraph 3, the target component in the gas is more easily adsorbed by the adsorbent, and therefore the concentration of the target component in the gas cell can be increased.

[0091] (Item 4) In the detection device described in any one of items 1 to 3, the first stimulation unit desorbs the first target component from the first adsorbent by microwave heating or heater heating the first adsorbent.

[0092] According to the detection device described in item 4, it is possible to easily control the desorption and adsorption of the target component to the adsorbent.

[0093] (Item 5) In the detection device described in item 4, the first stimulator heats the first adsorbent so as to generate a temperature gradient in the first gas cell.

[0094] According to the detection device described in paragraph 5, convection occurs within the gas cell, increasing the chances that the gas will flow over the surface of the adsorbent, thereby promoting adsorption of the target component.

[0095] (Item 6) The detection device according to item 4 or 5, further comprising a cooler that cools the first adsorbent heated by the first stimulation unit.

[0096] According to the detection device described in paragraph 6, it is possible to shorten the time until the adsorbent is able to adsorb the target component again, thereby shortening the time required for one detection cycle and thereby shortening the detection cycle.

[0097] (Item 7) The detection device described in any one of Items 1 to 6 further includes a light source that irradiates light onto the first adsorbent, and a detector that detects the first target component adsorbed to the first adsorbent based on the light emitted from the first adsorbent.

[0098] According to the detection device described in paragraph 7, even if a portion of the target component remains in the adsorbent, the concentration of the remaining target component can also be measured, and therefore the concentration of the target component in the gas cell can be determined more accurately than when only the concentration of the target component in the gas is measured.

[0099] (Item 8) In the detection device according to any one of items 1 to 7, the first gas cell has an optical resonator structure.

[0100] According to the detection device described in item 8, the light absorption of the target component in the gas cell can be amplified and detected, thereby improving the detection sensitivity of the target component.

[0101] (Item 9) In the detection device according to any one of items 1 to 8, the first gas cell has a separation section in a stage preceding the first gas cell that removes specific components other than the first target component.

[0102] According to the detection device described in paragraph 9, even if the gas in the gas pipe contains substances that are unnecessary for or that interfere with the measurement of the target component, the target component can be accurately measured.

[0103] (Item 10) The detection device described in any one of Items 1 to 9 includes a second gas cell into which a gas is introduced, and a second adsorbent that adsorbs a second target component in the gas, different from the first target component, and that is filled and arranged to form a second non-filled space inside the second gas cell. The second non-filled space is a space that is not filled with the second adsorbent. The detection device further includes a second stimulation unit that applies a stimulus to the second adsorbent to desorb the second target component into the second non-filled space, a second light source that irradiates light toward the second non-filled space, and a second detector that detects the light emitted from the second gas cell, and the measurement unit measures the second target component based on the output of the second detector.

[0104] According to the detection device described in paragraph 10, it is possible to simultaneously monitor a plurality of target components in a gas pipe.

[0105] (Item 11) A detection method according to another aspect includes the steps of introducing a gas from which detection of a target component is desired into a gas cell filled with an adsorbent that adsorbs a target component so as to form an unfilled space therein. The unfilled space is a space that is not filled with the adsorbent. The detection method further includes the steps of applying a stimulus to the adsorbent to desorb the target component into the unfilled space, irradiating light toward the unfilled space, detecting the light emitted from the gas cell with a detector, and measuring the target component based on the output from the detector.

[0106] According to the detection method described in paragraph 11, by disposing the adsorbent in the gas cell, the volume of the space up to the detection position of the target component desorbed from the adsorbent can be minimized. This prevents the concentrated target component from being diluted, enabling highly sensitive detection of the target component. Furthermore, by minimizing the transport path up to the detection position of the target component desorbed from the adsorbent, the target component can be detected in a short time. As described above, a detection device capable of detecting a target component in a gas in a short time and with high sensitivity can be provided.

[0107] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0108] 1, 1E, 1F Gas cell, 2, 2E, 2F, 21, 22 Adsorbent, 3, 3E, 3F Stimulation unit, 4, 4E, 721, 722 Light source, 5, 5E, 723, 724 Detector, 8 Gas piping, 11, 11F Inlet, 12, 12F Outlet, 14, 14F Housing, 15F Inner hole, 16F Space, 19, 19F Non-filled space, 61, 61E, 61F, 62, 62E, 62F Valve, 63, 63E, 64, 64E Piping, 65F, 66F Insulation material, 71, 71F Cooler, 73 Separation unit, 100 Detection device, 101, 101A, 101B, 101C, 101D, 101E, 101F Detection unit, 102 Control device, 103 processor, 104 memory, 131, 131F, 132, 132F, 725, 726, 727, 728 optical window, 141 inner wall.

Claims

1. A detection device comprising: a first gas cell into which a gas is introduced; and a first adsorbent that adsorbs a first target component in the gas, the first adsorbent being filled and arranged to form a first non-filled space inside the first gas cell, the first non-filled space being a space that is not filled with the first adsorbent; and further comprising: a first stimulation unit that stimulates the first adsorbent to cause the first target component to be desorbed into the first non-filled space; a first light source that irradiates light toward the first non-filled space; a first detector that detects the light emitted from the first gas cell; and a measurement unit that measures the first target component based on the output of the first detector.

2. The detection device according to claim 1, further comprising an inlet opening and closing part for adjusting the introduction of the gas into the first gas cell, and an exhaust opening and closing part for adjusting the exhaust of the gas from the first gas cell.

3. The detection device according to claim 1, wherein the first adsorbent has a honeycomb structure or a fin structure, and the first adsorbent is arranged so that the gas in the first gas cell passes through the honeycomb structure or the fin structure.

4. A detection device as described in claim 1, wherein the first stimulation unit desorbs the first target component from the first adsorbent by applying microwave heating or heater heating to the first adsorbent.

5. The detection device of claim 4, wherein the first stimulator heats the first adsorbent so as to generate a temperature gradient within the first gas cell.

6. The detection device according to claim 4, further comprising a cooler for cooling the first adsorbent heated by the first stimulation section.

7. The detection device described in claim 1, further comprising: a light source that irradiates light onto the first adsorbent; and a detector that detects the first target component adsorbed to the first adsorbent based on the light emitted from the first adsorbent.

8. The detection apparatus of claim 1, wherein the first gas cell comprises an optical resonator structure.

9. The detection device according to claim 1, wherein the first gas cell has a separation section, disposed upstream of the first gas cell, for removing specific components other than the first target component.

10. A detection device as described in claim 1, comprising: a second gas cell into which the gas is introduced; and a second adsorbent arranged so as to form a second non-filled space inside the second gas cell, the second non-filled space being a space not filled with the second adsorbent; and further comprising: a second stimulation unit that stimulates the second adsorbent to cause the second target component to be desorbed into the second non-filled space; a second light source that irradiates light toward the second non-filled space; and a second detector that detects the light emitted from the second gas cell; and the measurement unit measures the second target component based on the output of the second detector.

11. A detection method comprising the steps of: introducing a gas from which it is desired to detect a target component into a gas cell in which an adsorbent that adsorbs a target component is filled and arranged to form a non-filled space inside, the non-filled space being a space not filled with the adsorbent; providing a stimulus to the adsorbent to cause the target component to desorb into the non-filled space; irradiating light toward the non-filled space; detecting the light emitted from the gas cell with a detector; and measuring the target component based on the output from the detector.

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