JP2016080484A - Harmful gas detecting method, and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a harmful gas detecting method and apparatus that can continue to reliably measure harmful gas contents over a long period.SOLUTION: In a harmful gas detecting method by which the measurement object gas is brought into contact with a granular detection agent that changes its color when coming into contact with any harmful gas content and any color change of the detection agent is optically detected by color change detecting means, the average grain size of the detection agent is set to be less than 1/5 of the shortest dimension of the range of detection by the color change detecting means but not less than 200 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a harmful gas detection method and apparatus, and more particularly to a harmful gas detection method and apparatus for detecting a color change state of a substance that changes color by reacting with a specific gas component by an optical method.

  In semiconductor, flat panel display, and solar cell manufacturing processes, gas containing harmful components that are flammable, toxic, and corrosive are used in the material gas and cleaning gas, etc., so they are discharged from these manufacturing processes. Exhaust gas is removed by a detoxifying device. In addition, the abatement equipment is designed to ensure that the abatement process is performed in the abatement equipment and to detect the presence of harmful components in the process gas in order to confirm the replacement timing of the abatement agent. Gas detection means is provided.

  On the other hand, measuring the concentration of a specific gas component by detecting the color change state of a substance that changes color by reacting with a specific gas component by an optical method has been widely performed (for example, Patent Documents). 1-4.)

Japanese Patent Laid-Open No. 08-94530 JP 2003-270236 A JP 2011-2400 A JP 2005-62026 A

  However, the techniques described in Patent Documents 1 to 4 are instantaneous concentration measurement, and the measurement time is several minutes at the longest, and the concentration of a specific gas component in the gas sucked together with the atmosphere is measured. It was something to do. On the other hand, the confirmation of the abatement treatment status with the abatement device and the determination of the replacement time of the abatement agent require measurements over a long period of time during which the abatement device is operating. Since the process cannot use air, the techniques described in Patent Documents 1 to 4 cannot be employed.

  Therefore, an object of the present invention is to provide a harmful gas detection method and apparatus that can reliably perform continuous measurement of harmful gas components over a long period of time.

  In order to achieve the above object, the hazardous gas detection method of the present invention optically detects the color change of the detection agent by bringing the gas to be measured into contact with a granular detection agent that changes color by contact with a harmful gas component. In the noxious gas detection method for detecting the containing state of the noxious gas component in the measurement object gas by detecting the average particle size of the detection agent, the average particle diameter of the detection agent is 1/5 with respect to the shortest dimension of the detection range of the color change detection means. Less than 200 μm or more.

  Furthermore, the harmful gas detection method of the present invention is a processing gas derived from a detoxifying device that performs a detoxifying process of the exhaust gas discharged from a facility that exhausts exhaust gas containing a harmful gas component. It is characterized by continuously detecting during the period from the start of use of the detoxifying agent used in the detoxifying device until breakthrough, and detecting the content of harmful gas components to determine breakthrough of the detoxifying agent. It is said.

  Further, the detection agent is filled in the downstream side of the detoxification cylinder filled with the detoxification agent, the detection agent is filled in a detection tube having pipe connection portions at both ends, The detection agent is characterized in that discoloration is irreversible.

  The harmful gas detection device of the present invention is filled with a granular detection agent that changes color by contact with a harmful gas component in a detection tube having a transparent part at least in part, and the measurement target gas is circulated in the detection tube. In a harmful gas detection device for detecting the content of a harmful gas component in the measurement target gas by optically detecting the color change of the detection agent from the outside of the detection tube by a color change detection means, the average particle diameter of the detection agent is determined. The discoloration detecting means is characterized by being less than 1/5 of the shortest dimension of the detection range and 200 μm or more.

  Furthermore, in the harmful gas detection device of the present invention, the measurement target gas is a processing gas derived from a detoxification device that performs detoxification processing of the exhaust gas discharged from a facility that exhausts exhaust gas containing a harmful gas component. The detecting agent is characterized in that discoloration is irreversible.

  According to the present invention, it is possible to reliably detect the color change state of the detection agent while suppressing the influence of the shadow generated when optically detecting the color change of the granular detection agent.

It is explanatory drawing which shows the 1st form example of this invention. It is explanatory drawing which shows the 2nd form example of this invention. It is explanatory drawing which shows the 3rd form example of this invention. It is explanatory drawing of the detection agent unit used by the 3rd form example. It is explanatory drawing which shows the 4th example of this invention. It is explanatory drawing which shows the 5th example of a form of this invention. It is a figure which shows the relationship between the diameter / short side length, and a coincidence rate minimum in the Example and comparative example of this invention. It is a figure which similarly shows the relationship between a coincidence rate and elapsed time. It is a figure which similarly shows the relationship between the agreement rate with respect to elapsed time, and an exit density | concentration.

  FIG. 1 shows a first embodiment of the present invention. A detection agent unit 10 shown in this embodiment is a cylindrical detection tube 11 filled with a granular detection agent 12, and a detection tube. 11 is provided with a gas inflow portion 13 provided with a shutoff valve 13V, and the other end of the detection cylinder 11 is provided with a gas outflow portion 14 provided with a shutoff valve 14V. Further, connecting joints 13J and 14J are provided at the tips of the gas inflow portion 13 and the gas outflow portion 14, respectively. Further, a transparent window 15 is provided in a part of the detection cylinder 11, and a color change detection means 16 is provided outside the transparent window 15.

  The detection agent 12 to be used is appropriately selected according to the type of harmful gas component, and one that changes to a color different from the initial color upon contact with the harmful gas component is used. The shape of the detection agent 12 can be formed into an appropriate shape depending on the property of the detection agent 12 to be used. For example, a spherical shape, a tablet shape such as a flat shape or a spindle, and a cylindrical shape having an appropriate length and diameter. The thing of the shape of these etc. can be used suitably. Further, it may be formed by molding only the color-changing component, or may be one in which the color-changing component is supported on an appropriate carrier.

  The relationship between the color change detection means 16 and the size of the detection agent 12 is set such that the average particle diameter of the detection agent 12 is less than 1/5, preferably less than 1/10 with respect to the shortest dimension of the detection range of the color change detection means 16. To do. The shortest dimension of the detection range of the color change detection unit 16 is a range that can be recognized by the measurement unit (sensor unit) of the color change detection unit 16 or the size of the narrowest portion of the transparent window 15 provided in the detection cylinder 11. For example, when the range that can be recognized by the measurement unit of the color change detection means 16 is a circle with a diameter of 30 mm and the size of the transparent window 15 is a square with a size of 50 mm × 50 mm, the shortest dimension among them is 30 mm. When the size of the transparent window 15 is a rectangle of 50 mm × 20 mm, the shortest dimension of the detection range of the color change detection means 16 is 20 mm, which is the shortest dimension of the detection range of the color change detection means 16. Become.

  Therefore, the average particle diameter of the detection agent 12 when the shortest dimension is 30 mm is less than 6 mm, preferably less than 3 mm, and the average particle diameter of the detection agent 12 when the shortest dimension is 20 mm is less than 4 mm, preferably less than 2 mm. Become. If the average particle size is too small, there is a problem in handling properties and a problem in gas flowability. Therefore, the average particle size is usually preferably 200 μm or more. The average particle diameter of the detection agent 12 in the present invention is the average value of the particle diameter in the case of a spherical shape, but the average value of the maximum diameter in the case of a tablet shape, and the average value of the maximum length in the case of a rod shape. Become.

  When a large number of detection agents 12 are filled in the detection cylinder 11, the detection agents 12 are in a three-dimensionally complicated overlapping state, so that when the detection agent 12 is optically viewed by the discoloration detection means 16, it becomes a shadow. There is a part. In particular, when the average particle size of the detection agent 12 becomes larger than the detection range of the color change detection means 16, the shadow ratio in the detection range varies depending on the filling state and detection position of the detection agent 12. The shadow portion is recognized as black by the color change detection means 16 both before and after the color change of the detection agent 12. Therefore, if there are many shadow portions, the detection of the color change state by the color change detection means 16 becomes unstable. A large error may occur in the detection result. Therefore, as described above, by setting the average particle diameter of the detection agent 12 to less than 1/5, preferably less than 1/10, with respect to the shortest dimension of the detection range of the color change detection means 16, the color change of the detection agent 12 is achieved. When optically measuring the state, the influence of shadows caused by the overlap of the granular materials can be reduced, and the discoloration state of the detection agent 12 can be reliably detected.

  Further, before use, the shutoff valves 13V and 14V are closed to hold the detection agent 12 in a sealed state, and when used, the shutoff valves 13V and 14V are opened after connecting to a predetermined pipe via the connection joints 13J and 14J. Thus, the use can be started in the initial state without deteriorating the detection agent 12.

  Furthermore, even if the gas to be measured is an inert gas, the color change of the detection agent 12 can be reliably detected, and the color change state can be detected more reliably by using a detection agent whose color change is irreversible.

  FIG. 2 shows a second embodiment of the present invention. In the following description, the same components as those of the harmful gas detection device shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The detection agent unit 20 shown in the present embodiment is filled with the same granular detection agent 12 in a detection tube 21 made of metal and formed in a rectangular tube shape, and is elongated on at least one side surface of the detection tube 21. A rectangular transparent window 22 is provided. The discoloration detecting means 16 is provided in one transparent window 22, and usually the shortest dimension of the detection range of the discoloration detecting means 16 is often the short side dimension of the transparent window 22.

  3 and 4 show a third embodiment of the present invention. The detection agent unit 25 shown in the present embodiment holds the detection agent 12 between a pair of packings 27 and 27 inserted into a glass tube 26 serving as a detection cylinder. As shown in FIG. 4, the glass tube 26 before use is sealed in the glass tube 26 by sealing both ends 26a and 26a after inserting the packing 27 and the detection agent 12, before use. The deterioration of the detection agent 12 is prevented. At the time of use, as shown in FIG. 3, both end portions 26a and 26a are cut and connected to predetermined pipes 28 and 28 by appropriate connecting members 28J and 28J.

  FIG. 5 shows a fourth embodiment of the present invention. In this embodiment, the detection agent 12 is filled in a detoxification cylinder 31 provided in a detoxification apparatus that performs a detoxification process of the exhaust gas discharged from a facility that discharges exhaust gas containing harmful gas components in a dry manner. Yes. The detoxifying cylinder 31 has an upper detoxifying agent 34 and a lower backup agent 35 in a cylindrical body in which an exhaust gas introduction pipe 32 is provided in the cylindrical celestial body portion 31a and a processing gas outlet pipe 33 is provided on the lower side of the peripheral wall. The detection agent 12 is filled on one side of the lower end portion of the detoxifying agent 34.

  A transparent window 36 capable of observing the discoloration state of the detection agent 12 from the outside is provided on the cylindrical peripheral wall of the portion filled with the detection agent 12, and the same discoloration detection means 16 as described above is provided outside the transparent window 36. ing. The detoxifying agent 34 and the backup agent 35 are those capable of detoxifying harmful gas components, and may be the same agent or different agents. Moreover, the stacking height of both is arbitrary.

  Exhaust gas containing harmful gas components flows into the detoxification cylinder 31, and the detoxification treatment of the noxious gas components proceeds in order from the upstream side of the detoxifying agent 34, and when the breakthrough of the detoxifying agent 34 approaches, The harmful gas component contacts the detection agent 12, and the detection agent 12 changes color. When the discoloration of the detection agent 12 is detected by the discoloration detection means 16, the detected discoloration data is processed by a calculation means (not shown), and when the calculation result processed by the calculation means reaches a preset color change state, the external output means The breakthrough of the pesticide 34 is notified to the outside.

  FIG. 6 shows a fifth embodiment of the present invention. In this embodiment, instead of filling the abatement cylinder 31 shown in the fourth embodiment with the detection agent 12, a gas suction pipe 42 connected to a harmful gas detection unit 41 at the lower end of the removal agent 34. Is provided. The harmful gas detection unit 41 uses the detection agent unit 10 shown in the first embodiment, and the gas suction pipe is connected to the connection joint 13J of the gas inflow portion 13 of the detection cylinder 11 via the connection pipe 42a. 42 is connected, and a suction means 44 is connected to the connection joint 14 </ b> J of the gas outflow portion 14 via a connection pipe 44 a provided with a flow meter 43.

  The gas suction pipe 42 has a large number of gas suction ports, and the gas flowing from the detoxifying agent 34 toward the backup agent 35 inside the detoxifying cylinder 31 is sucked by the suction means 44 and introduced into the detection cylinder 11. Is done. The breakthrough of the detoxifying agent 34 can be determined by detecting the color change state of the detection agent 12 in the detection cylinder 11 by the color change detection means 16.

[Examples and Comparative Examples]
As shown in Table 1 and Table 2, white or light spherical detectors with different average diameters are filled in glass tubes with a diameter of 50 mm, and the range (detection spot size) that can be recognized by the measuring part of the color change detection means is various dimensions. The detection windows of various sizes were formed by appropriately covering the periphery of the glass tube. In the state before discoloration, the detection range is moved by 1 mm in the longitudinal direction of the glass tube and the data detected by the discoloration detection means are compared. The coincidence rate. The results are shown in Tables 1 and 2 and FIG.

  From this experimental result, when the diameter of the detection agent was less than 1/5 with respect to the shortest dimension of the detection range of the color change detection means (Table 1), the value was 80% or more, whereas 1 / In the case of 5 or more (Table 2), it may be 40% or less, and it can be seen that the detection sensitivity of the discolored state is lowered.

  The detection agent used in Example 12 in the above examples (average diameter 200 μm) and the detection agent used in Comparative Example 10 in the comparative example (average diameter 1 mm) were each filled into a glass tube having a diameter of 20 mm. The detection spot size was 1 mm in diameter, and the detection window size was 5 mm × 5 mm. Teaching was performed before the gas to be measured was distributed, and the initial value was set to 100% coincidence.

  A gas to be measured in which boron trifluoride was diluted to 1 ppm with nitrogen was passed through the glass tube to measure the color change state of the detection agent (Example 39 and Comparative Example 20). This experiment was performed three times, and the state of decrease in the coincidence rate was calculated. The result is shown in FIG. It can be seen that in Example 39, the coincidence rate largely decreased due to the reaction with boron trifluoride, whereas in Comparative Example 20, the decrease in the coincidence rate varies. If the measurement results vary in this way, accurate measurement cannot be expected.

  A glass tube having a diameter of 5 mm was filled with the detection agent having an average diameter of 200 μm. The detection spot size was 1 mm in diameter, and the detection window size was 5 mm × 5 mm. A stainless steel column with a diameter of 50 mm was filled with a detoxifying agent for arsine at a height of 200 mm, and the glass tube filled with the detecting agent was disposed at a position 150 mm from the gas inflow side of the detoxifying agent (see the fourth embodiment). ).

  An arsine high-sensitivity detector (KL8000) manufactured by bionics equipment was connected to the outlet of the stainless steel column, and a gas to be measured in which arsine was diluted to 1% with nitrogen was introduced into the stainless steel column at LV = 5 cm / sec (Example 40). ). FIG. 9 shows the state of decrease in the coincidence rate of the detection agent and the state of change in the arsine concentration detected by the detector. From this result, it can be seen that the coincidence ratio of the detection agent is lowered before the arsine concentration at the outlet of the stainless steel column shows 5 ppb which is the TLV value (threshold limit value), and arsine flows down to the position of the detection agent. Therefore, it can be seen that this is effective as a detection means for detecting breakthrough of the detoxifying cylinder.

DESCRIPTION OF SYMBOLS 10 ... Detection agent unit, 11 ... Detection cylinder, 12 ... Detection agent, 13 ... Gas inflow part, 13J ... Connection joint, 13V ... Shut-off valve, 14 ... Gas outflow part, 14J ... Connection joint, 14V ... Shut-off valve, 15 ... Transparent window, 16 ... Discoloration detecting means, 20 ... Detection agent unit, 21 ... Detection cylinder, 22 ... Transparent window, 25 ... Detection agent unit, 26 ... Glass tube, 26a ... Both ends, 27 ... Packing, 28 ... Piping, 28J DESCRIPTION OF SYMBOLS Connection member 31 ... Detoxification cylinder, 31a ... Cylindrical celestial body part, 32 ... Exhaust gas introduction piping, 33 ... Processing gas outlet piping, 34 ... Detoxification agent, 35 ... Backup agent, 36 ... Transparent window, 41 ... Toxic gas detection 42, gas suction pipe, 42a ... connection piping, 43 ... flow meter, 44 ... suction means, 44a ... connection piping

Claims (8)

  Content state of harmful gas components in the measurement target gas by contacting the measurement target gas with a granular detection agent that changes color due to contact with the noxious gas component and optically detecting the color change of the detection agent with a color change detection means In the noxious gas detection method, the average particle diameter of the detection agent is less than 1/5 with respect to the shortest dimension of the detection range of the color change detection means, and is no less than 200 μm Detection method.   The measurement target gas is a processing gas derived from a detoxification device that performs detoxification processing of the exhaust gas discharged from a facility that discharges exhaust gas containing harmful gas components, and is used for the detoxification device The hazardous gas detection method according to claim 1, wherein the breakthrough of the detoxifying agent is determined by detecting the content state of the harmful gas component continuously during the period from the start of use of the chemical to the breakthrough. .   The harmful gas detection method according to claim 2, wherein the detection agent is filled downstream of a detoxification cylinder filled with the detoxification agent.   The harmful gas detection method according to claim 1 or 2, wherein the detection agent is filled in a detection tube having pipe connection portions at both ends.   The harmful gas detection method according to claim 1, wherein the detection agent is irreversible in discoloration.   At least a part of the detection tube having a transparent portion is filled with a granular detection agent that changes color by contact with harmful gas components, and the gas to be measured is circulated in the detection tube to change the color of the detection agent to the outside of the detection tube. In the harmful gas detection device that detects the content of the harmful gas component in the measurement target gas by optically detecting from the color change detection means, the average particle diameter of the detection agent is determined within the detection range of the color change detection means. A harmful gas detection device characterized by being less than 1/5 of the shortest dimension and 200 μm or more.   The harmful gas according to claim 6, wherein the measurement target gas is a processing gas derived from a detoxification device that performs a detoxification process of the exhaust gas discharged from a facility that discharges exhaust gas containing a harmful gas component. Detection device.   The harmful gas detection device according to claim 6 or 7, wherein the detection agent is irreversible in discoloration.

Images