CN114375395A

CN114375395A - Gas analysis method and gas analysis device

Info

Publication number: CN114375395A
Application number: CN202080064347.6A
Authority: CN
Inventors: 板桥亨久
Original assignee: Shimadzu Corp
Current assignee: Shimadzu Corp
Priority date: 2019-09-25
Filing date: 2020-09-02
Publication date: 2022-04-19
Also published as: WO2021059905A1

Abstract

The sample gas channel (110) connects the upstream side of the concentrator (41) to the sample introduction section (1). The standard gas channel (130) connects the standard gas supply unit (6) to the sample gas channel (110) at the junction (121), and introduces the standard gas from the upstream side into the concentrator (41). The carrier gas flow path (140) connects the downstream side of the concentrator (41) to the carrier gas supply unit (5) and introduces the carrier gas from the downstream side into the concentrator (41). The mixer (44) mixes the standard gas introduced into the concentrator (41) through the standard gas passage (6) with the carrier gas supplied from the carrier gas supply unit (5).

Description

Gas analysis method and gas analysis device

Technical Field

The present invention relates to a gas analysis method and a gas analysis apparatus.

Background

For example, when analyzing an extremely small amount of components in a sample gas as in the case of analyzing environmental pollutants in the air, a gas analyzer of a thermal desorption method is sometimes used (for example, see patent document 1 below). Examples of the environmental pollutants include VOCs (Volatile Organic Compounds).

Such a gas analyzer includes a concentrator for concentrating a sample gas. The concentrator is provided with a trap tube filled with a trapping agent therein. The components in the sample gas can be trapped in the trap tube by introducing the sample gas into the trap tube in a low temperature state. The components trapped in the trap tube can be detached by heating the trap tube. The carrier gas can be introduced into the trap tube while the component trapped in the trap tube is desorbed, and the desorbed high-concentration component can be supplied to the detector and detected.

The concentration of the component in the sample gas detected by the detector is determined using the calibration curve. The calibration curve is created using a standard gas in which a component to be measured (target component) is contained at a known concentration. Since a commercially available standard gas contains a target component at a relatively high concentration, it is usually used after being diluted to a low concentration with a diluent gas. The diluted standard gas is supplied to a detector without passing through a concentrator, and components in the standard gas are detected by the detector.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-337158

Disclosure of Invention

Problems to be solved by the invention

In the conventional configuration as described above, the components in the sample gas are once collected by the concentrator and then detected by the detector. On the other hand, the components in the standard gas are detected by the detector without passing through the concentrator. Therefore, an error in the concentration ratio in the concentrator may affect the measurement result of the concentration of the component in the sample gas.

Therefore, it is considered that the following structure is adopted: similarly to the sample gas, the standard gas is once introduced into the concentrator to trap a component in the standard gas by the concentrator, and then the component is desorbed and supplied to the detector. In this case, since the components in the standard gas are concentrated in the concentrator and then detected by the detector, there is an advantage that the influence of the error in the concentration ratio of the concentrator on the measurement result can be suppressed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas analysis method and a gas analysis apparatus that can optimize a configuration in which a sample gas and a standard gas are introduced into a concentrator.

Means for solving the problems

A first aspect of the present invention is a gas analysis method including the steps of: concentrating the components in the sample gas by using a concentrator; supplying the concentrated component to a detector by supplying a carrier gas to the concentrator; supplying the concentrated component to the detector by supplying a carrier gas to the concentrator after concentrating the component in a mixed gas generated by mixing a standard gas with the carrier gas by the concentrator; and measuring the concentration of the component in the sample gas based on the detection intensity of the component in the sample gas and the detection intensity of the component in the mixed gas in the detector.

A second aspect of the present invention is a gas analyzer including a concentrator, a detector, a carrier gas supply unit, a standard gas supply unit, a sample gas flow path, a standard gas flow path, a carrier gas flow path, a pump, a flow meter, and a mixer. The concentrator concentrates the sample gas introduced from the sample introduction part. The detector is configured to detect a component in the sample gas concentrated by the concentrator using the detector. The carrier gas supply section supplies a carrier gas. The standard gas supply unit supplies a standard gas. The sample gas flow path communicates an upstream side of the concentrator with the sample introduction portion. The standard gas flow path communicates the standard gas supply section with the sample gas flow path at a first confluence section, and introduces the standard gas from the upstream side to the concentrator via the sample gas flow path. The carrier gas flow path communicates the downstream side of the concentrator with the carrier gas supply unit, and introduces the carrier gas from the downstream side into the concentrator. The pump is provided downstream of the first confluence section, and introduces the sample gas or the standard gas from the upstream side into the concentrator. The flow meter is provided on the downstream side of the first merging portion, and measures the flow rate of the sample gas or the flow rate of the standard gas introduced into the concentrator. The mixer mixes the standard gas introduced into the concentrator through the standard gas passage with the carrier gas supplied from the carrier gas supply unit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the first aspect of the present invention, the standard gas can be diluted with the carrier gas in the configuration in which the sample gas and the standard gas are introduced into the concentrator. This eliminates the need for a separate diluter, and thus enables an optimized configuration.

According to the second aspect of the present invention, the standard gas can be diluted with the carrier gas in the configuration in which the sample gas and the standard gas are introduced into the concentrator. This eliminates the need for a separate diluter, and thus enables an optimized configuration.

Drawings

Fig. 1 is a flow path diagram showing an embodiment of a gas analyzer.

Fig. 2A is a flow chart for explaining an operation at the time of zero point calibration.

Fig. 2B is a flow chart for explaining the operation at the time of zero point calibration.

Fig. 3A is a flow chart for explaining the operation in the span calibration.

Fig. 3B is a flow chart for explaining the operation in the span calibration.

Fig. 3C is a flow chart for explaining the operation in the span calibration.

Fig. 4A is a flow chart for explaining an operation in analysis.

Fig. 4B is a flow chart for explaining the operation during analysis.

Fig. 4C is a flow chart for explaining the operation during analysis.

Fig. 4D is a flow chart for explaining the operation during analysis.

Fig. 5A is a flow chart for explaining an operation during regeneration.

Fig. 5B is a flow chart for explaining the operation during regeneration.

Detailed Description

1. Integral structure of gas analysis device

Fig. 1 is a flow path diagram showing an embodiment of a gas analyzer. This gas analysis apparatus performs analysis by detecting a component in the sample gas introduced from the sample introduction portion 1 with a detector. The detector is, for example, a gas chromatograph 2 that separates and detects components in the sample gas using a column (not shown). As the component to be analyzed, for example, an environmental pollutant such as VOC contained in the atmosphere can be exemplified, but the present invention is not limited thereto.

The sample gas introduced from the sample introduction part 1 passes through the filter 3 to remove foreign substances. The sample gas having passed through the filter 3 can be directly supplied to the gas chromatograph 2 via the flow path 101, but can also be supplied to the concentration device 4 via a flow path 102 branching off from the flow path 101 at a branching portion 111.

When the sample gas is directly supplied to the gas chromatograph 2, the sample gas is introduced from the flow path 101 to the gas chromatograph 2 by driving the pump 7 connected to the gas chromatograph 2. On the other hand, the sample gas supplied from the flow path 101 to the concentration device 4 through the flow path 102 is concentrated in the concentration device 4, and then supplied to the gas chromatograph 2 through the flow path 103.

A carrier gas supply unit 5 and a standard gas supply unit 6 are fluidly connected to the concentration device 4. The carrier gas supply unit 5 supplies an inert gas such as nitrogen as a carrier gas. The standard gas supply unit 6 supplies a standard gas. As the standard gas, a span gas (calibration gas) containing one or more target components at predetermined concentrations is used. The carrier gas supply unit 5 and the standard gas supply unit 6 may be constituted by gas cylinders that store gas in a compressed state.

The concentrator 4 has a structure in which a concentrator 41, a flow meter 42, a pump 43, a mixer 44, and the like are housed in a casing 40. The concentrator 41 is for concentrating components in a gas such as a sample gas introduced from the sample introduction unit 1, and includes a trap tube 411, a heating unit 412, a cooling unit 413, and the like. The trap pipe 411 is filled with a trapping agent for trapping components in the gas. The heating part 412 is for heating the trap pipe 411, and includes, for example, an electric heater. The cooling portion 413 is for cooling the trap pipe 411, and includes a peltier element, for example.

In the concentrator 41, the component in the gas can be trapped in the trap pipe 411 and concentrated by supplying the gas to the trap pipe 411 while cooling the trap pipe 411 by the cooling unit 413. The components trapped in the trap tube 411 can be desorbed by heating the trap tube 411 by the heating unit 412. If the carrier gas is introduced into the trap pipe 411 while the component trapped in the trap pipe 411 is desorbed, the desorbed high-concentration component can be discharged from the concentrator 41.

The flow path 102 for introducing the sample gas into the concentration device 4 communicates with the upstream side of the trap pipe 411 via the valve 212 and the flow path 104. The valve 212 is, for example, a three-way valve, and communicates with the flow path 103 described above in addition to the

flow paths

102 and 104. When the valve 212 is in the closed state, the

flow paths

102 and 104 are communicated, and when the valve 212 is energized to be in the open state, the

flow paths

103 and 104 are communicated.

In this way, the

channels

102, 103, and 104 can be selectively communicated by the switching valve 212. The

flow paths

102 and 104 constitute a sample gas flow path 110 for communicating the upstream side of the concentrator 41 with the sample introduction section 1. This allows the sample gas to be introduced into the concentrator 41 through the sample gas passage 110, and the components in the sample gas to be concentrated by the concentrator 41.

The downstream side of the trap pipe 411 communicates with the flow path 105. The flow path 105 communicates with the flow path 106 via a valve 213. The valve 213 is, for example, a three-way valve, and communicates with the flow path 107 in addition to the

flow paths

105 and 106. When the valve 213 is in a closed state, the

flow paths

105 and 106 are communicated with each other, and when the valve 213 is in an open state by energization, the

flow paths

105 and 107 are communicated with each other. Thus, the

channels

105, 106, and 107 can be selectively communicated with each other by the switching valve 213.

The flow path 107 constitutes an exhaust flow path communicating with the outside of the concentration device 4. The flow meter 42 and the pump 43 are provided in the flow path 107 in this order from the upstream side (the trap pipe 411 side). When the pump 43 is driven after the pump 43 is communicated with the trap pipe 411 by opening the valve 213, gas (for example, sample gas) is introduced into the trap pipe 411 from the upstream side, and the gas having passed through the trap pipe 411 is discharged to the outside through the flow path 107. At this time, the flow rate of the gas introduced into the trap pipe 411 can be measured by measuring the flow rate of the gas passing through the flow meter 42. A valve 210 that can be opened and closed manually may be provided between the flow meter 42 and the pump 43 in the flow path 107.

The flow path 106 communicates with the carrier gas supply unit 5 and the standard gas supply unit 6 via the mixer 44. Specifically, the flow path 106 is branched into 2

flow paths

162 and 163 at the branching portion 161, one flow path 162 communicates with the carrier gas supply portion 5, and the other flow path 163 communicates with the standard gas supply portion 6. The mixer 44 is a flow rate controller capable of controlling the ratio of the gas flowing through each of the 2

flow paths

162 and 163.

The flow path 102 and the flow path 106 can communicate via a flow path 108. That is, the flow path 108 branches from the flow path 106 at the branching portion 164, and merges with the flow path 102 at the merging portion 121. The branch portion 164 is provided between the branch portion 161 and the valve 213, for example. The flow path 108 is provided with a valve 211 formed of a two-way valve, for example. When the valve 211 is in the closed state, the flow path 108 is blocked, and when the valve 211 is energized to be in the open state, the flow path 108 is opened.

The

flow paths

106, 108, and 163 constitute a standard gas flow path 130 for allowing the standard gas supply section 6 and the sample gas flow path 110 to communicate at a junction (first junction) 121. The standard gas channel 130 introduces the standard gas from the confluence section 121 to the concentrator 41 from the upstream side through the sample gas channel 110. Thereby, the standard gas diluted with the mixed carrier gas in the mixer 44 can be concentrated by the concentrator 41. At least one of the flowmeter 42 and the pump 43 is preferably provided downstream of the junction 121, and may be provided in

other flow paths

102, 104, and 105, as well as in the flow path 107.

The

passages

105, 106, and 162 constitute a carrier gas passage 140 for communicating the downstream side of the concentrator 41 with the carrier gas supply unit 5. When the valve 213 is in the closed state, the flow path 105 and the flow path 106 communicate with each other, and the carrier gas can be introduced from the carrier gas flow path 140 to the concentrator 41 from the downstream side. The flow path 107 communicates with the carrier gas flow path 140 at a valve (second merging portion) 213. The

flow paths

103 and 104 constitute a lead-out flow path 120 for communicating the upstream side of the concentrator 41 with the gas chromatograph 2. The sample gas or the standard gas concentrated by the concentrator 41 is guided to the guide-out passage 120 by the carrier gas guided to the downstream side of the concentrator 41 from the carrier gas passage 140.

The flow path 102 and the flow path 107 can communicate with each other through a flow path 109. That is, the flow path 109 branches from the flow path 102 at the branching section 122, and merges with the flow path 107 at the merging section 171. The merging section 171 is provided between the flow meter 42 and the pump 43, for example. The flow path 109 is provided with a valve 214 formed of a two-way valve, for example. When the valve 214 is in the closed state, the flow path 109 is blocked, and when the valve 214 is energized to be in the open state, the flow path 109 is opened.

If the mixer 44 is controlled, the carrier gas supplied from the carrier gas supply unit 5 can be mixed with the standard gas introduced into the concentrator 41 through the standard gas passage 130. The mixer 44 can arbitrarily adjust the mixing ratio of the carrier gas to the standard gas. Further, only one of the carrier gas and the standard gas may be introduced into the flow channel 106.

The concentration of the component in the sample gas detected in the gas chromatograph 2 is measured using a calibration curve. In the gas analyzer according to the present embodiment, zero point calibration and span calibration are performed to create a calibration curve. In the zero point calibration, the carrier gas supplied from the carrier gas supply unit 5 is supplied to the gas chromatograph 2 as a zero gas (a gas not containing the target component), and the detection intensity at this time is measured as a zero point. In the span calibration, the standard gas (gas containing the target component at a known concentration) supplied from the standard gas supply unit 6 is diluted with the carrier gas, introduced into the concentrator 41, concentrated by the concentrator 41, and supplied to the gas chromatograph 2, and the detection intensity at that time is measured as a span point. In this way, a calibration curve indicating the relationship between the detection intensity and the concentration of the target component can be created based on the measured zero point and the measured span point.

The

valves

211, 212, 213, and 214 are, for example, solenoid valves. In order to adjust the temperature of each of the

valves

211, 212, 213, and 214, a temperature sensor, a heating unit, a cooling unit, and the like (all not shown) may be provided in association with each of the

valves

211, 212, 213, and 214. The

valves

211, 212, 213, and 214, the concentrator 41, the pump 43, the mixer 44, and the like are controlled by a control Unit including a CPU (Central Processing Unit), for example.

2. Action at zero point calibration

Fig. 2A and 2B are flow charts for explaining the operation at the time of zero point calibration. At the time of zero point calibration, the

valves

211, 212, 213, and 214 are heated and temperature-adjusted so as to have a predetermined temperature (for example, 150 ℃).

At the time of zero point calibration, first, the

valves

211, 213 are switched to the open state, and the pump 43 starts to be driven. Further, the carrier gas is supplied from the carrier gas supply portion 5 by controlling the mixer 44. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 2A, the carrier gas supplied from carrier gas supply unit 5 flows through

flow paths

162, 106, 108, 102, and 104 in this order, flows into trap tube 411 from the upstream side, and is then discharged through

flow paths

105 and 107. This allows the carrier gas to pass through the trap pipe 411, thereby enabling purging before zero point calibration.

Thereafter, the

valves

211 and 213 are switched to the closed state, and the trap pipe 411 starts to be heated by the heating unit 412. Thereby, the temperature of the trap pipe 411 gradually rises toward the target temperature (e.g., 280 ℃). At this time, the pump 43 is stopped from being driven, and the gas supply from the mixer 44 is also stopped.

Then, when the trap pipe 411 is heated to the target temperature, the carrier gas is supplied from the carrier gas supply unit 5 by controlling the mixer 44 while controlling the heating unit 412 to maintain the target temperature and switching the valve 212 to the open state. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 2B, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

162, 106, and 105 in this order, flows into the trap pipe 411 from the downstream side, and is then supplied to the gas chromatograph 2 via the

channels

104 and 103. Thereby, the carrier gas having passed through the trap pipe 411 is supplied as a zero gas to the gas chromatograph 2, and the detection intensity in the gas chromatograph 2 at this time is measured as a zero point. In this way, when performing the zero calibration in the present embodiment, the carrier gas can be supplied as a zero gas to the gas chromatograph 2 (zero calibration step).

3. Operation in Range calibration

Fig. 3A to 3C are flow path diagrams for explaining the operation in the span calibration. During span calibration, the

valves

211, 212, 213, and 214 are heated and temperature-adjusted to a predetermined temperature (e.g., 150 ℃).

In the span calibration, first, the

valves

211 and 213 are switched to the open state, and the pump 43 starts to be driven. Further, the carrier gas is supplied from the carrier gas supply portion 5 by controlling the mixer 44. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 3A, the carrier gas supplied from carrier gas supply unit 5 flows through

flow paths

162, 106, 108, 102, and 104 in this order, flows into trap pipe 411 from the upstream side, and is then discharged through

flow paths

105 and 107. This allows the carrier gas to pass through the trap pipe 411, thereby enabling purging before span calibration.

After that, the

valves

211 and 213 are returned to the closed state, and the driving of the pump 43 is stopped, and the supply of the gas from the mixer 44 is also stopped. In this state, the cooling of trap pipe 411 by cooling unit 413 is started. Thereby, the temperature of the trap pipe 411 gradually decreases toward the target temperature (e.g., 40 ℃). Then, when trap pipe 411 is cooled to the target temperature, while cooling unit 413 is controlled to maintain the target temperature,

valves

211 and 213 are switched to the open state again, and driving of pump 43 is restarted and mixer 44 is controlled, thereby supplying the standard gas from standard gas supply unit 6. At this time, the standard gas is diluted by mixing the carrier gas supplied from the carrier gas supply unit 5.

In this case, as shown by the broken line in fig. 3B, the standard gas supplied from the standard gas supply unit 6 is diluted by the carrier gas supplied from the carrier gas supply unit 5, flows through the

flow paths

106, 108, 102, and 104 in this order, flows into the trap pipe 411 from the upstream side, and is then discharged via the

flow paths

105 and 107. This allows components in the diluted standard gas to be trapped in the trap tube 411 and concentrated. At this time, the flow rate of the gas having passed through the trap pipe 411 is measured by the flow meter 42, and the concentration ratio of the component in the standard gas trapped in the trap pipe 411 can be calculated based on the flow rate and the mixing ratio (dilution ratio) in the mixer 44.

Thereafter, the

valves

211 and 213 are switched to the closed state, and the trap pipe 411 starts to be heated by the heating unit 412. Thereby, the temperature of the trap pipe 411 gradually increases toward the target temperature (e.g., 280 ℃). At this time, the pump 43 is stopped from being driven, and the gas supply from the mixer 44 is also stopped.

When the temperature of the trap pipe 411 reaches the target temperature, the carrier gas is supplied from the carrier gas supply unit 5 by controlling the mixer 44 while controlling the heating unit 412 to maintain the target temperature and switching the valve 212 to the open state. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 3C, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

104 and 103. Thereby, the components in the standard gas desorbed from trap tube 411 are supplied to gas chromatograph 2, and the detection intensity in gas chromatograph 2 at this time is measured as a span point.

In this way, at the time of the span calibration in the present embodiment, by concentrating the component in the mixed gas generated by mixing the standard gas and the carrier gas by the concentrator 41 and then supplying the carrier gas to the concentrator 41, the concentrated component can be supplied to the gas chromatograph 2 (span calibration step). Then, a calibration curve is created based on the detected intensity of the component in the mixed gas measured in the throughput calibration step and the detected intensity of the component in the carrier gas measured in the zero point calibration step (calibration curve creation step).

Thereafter, the cooling of trap pipe 411 by cooling unit 413 is started while the supply of the carrier gas from carrier gas supply unit 5 is continued. Thus, even after the separation of the component in the standard gas from the trap pipe 411 is completed, the flow of the carrier gas indicated by the broken line in fig. 3C is maintained, and therefore, the inside of the flow path 103 can be purged.

4. Action at the time of analysis

Fig. 4A to 4D are flow path diagrams for explaining the operation during analysis. When analyzing the components in the sample gas, the

valves

In performing the analysis, first, the valve 214 is switched to the open state, and the pump 43 starts to be driven. Further, cooling of trap pipe 411 by cooling section 413 is started, and mixer 44 is controlled, whereby carrier gas is supplied from carrier gas supply section 5. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 4A, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

162, 106, and 105 in this order, flows into the trap pipe 411 from the downstream side, and is then discharged through the

channels

104, 109, and 107. This allows the gas remaining in the trap pipe 411 and other channels to be replaced with the carrier gas.

After that, the valve 214 is returned to the closed state, and the driving of the pump 43 is stopped, and the supply of the gas from the mixer 44 is also stopped. In this state, the cooling of trap pipe 411 by cooling unit 413 is continued, and the temperature of trap pipe 411 gradually decreases toward a target temperature (for example, 40 ℃). Then, when trap pipe 411 is cooled to the target temperature,

valves

213 and 214 are switched to the open state while cooling unit 413 is controlled so as to maintain the target temperature, and driving of pump 43 is restarted.

In this case, as shown by the broken line in fig. 4B, the sample gas introduced from the sample introduction section 1 flows through the

channels

101, 102, and 104 in sequence, flows into the trap tube 411 from the upstream side, and is then discharged through the

channels

105 and 107. This allows components in the sample gas to be trapped in the trap tube 411 and concentrated. At this time, the flow rate of the gas having passed through the trap tube 411 is measured by the flow meter 42, and the concentration ratio of the component in the sample gas trapped in the trap tube 411 can be calculated based on the flow rate. Further, a part of the sample gas introduced from the sample introduction section 1 flows from the branch section 122 to the channel 109, and is discharged from the junction 171 through the channel 107 without passing through the trap tube 411. The resistance in the channel 109 is made sufficiently larger than the resistance in the trap tube 411, and the channel 102 can be filled with the sample gas.

Thereafter, the carrier gas is supplied from the carrier gas supply unit 5 by keeping the cooling unit 413 at the target temperature, switching the

valves

213 and 214 to the closed state, stopping the driving of the pump 43, and controlling the mixer 44. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 4C, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

162, 106, and 105 in this order, flows into the trap tube 411 from the downstream side, and is then discharged from the sample introduction unit 1 via the

channels

104, 102, and 101. This enables removal of oxygen in trap pipe 411.

After that, the trap pipe 411 starts to be heated by the heating unit 412. Thereby, the temperature of the trap pipe 411 gradually increases toward the target temperature (e.g., 280 ℃). At this time, the supply of gas from the mixer 44 is stopped.

In this case, as shown by the broken line in fig. 4D, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

104 and 103. Thereby, the components in the sample gas desorbed from the trap tube 411 are supplied to the gas chromatograph 2, and the detection intensity of the components in the sample gas is measured in the gas chromatograph 2.

In this way, when the analysis in the present embodiment is performed, the concentrated component can be supplied to the gas chromatograph 2 by concentrating the component in the sample gas by the concentrator 41 and then supplying the carrier gas to the concentrator 41 (analysis step). Then, the concentration of the component in the sample gas can be measured based on the detection intensity of the component in the sample gas measured in the analyzing step and the detection intensity of the component in the mixed gas measured in the span calibrating step (concentration measuring step). More specifically, in the concentration measuring step, the concentration of the component in the sample gas can be measured based on the detection intensity of the component in the sample gas measured in the analyzing step and the calibration curve created in the calibration curve creating step.

Thereafter, the cooling of trap pipe 411 by cooling unit 413 is started while the supply of the carrier gas from carrier gas supply unit 5 is continued. Thus, even after the separation of the component in the sample gas from the trap tube 411 is completed, the flow of the carrier gas indicated by the broken line in fig. 4D is maintained, and therefore, the inside of the flow path 103 can be purged.

5. Operation at the time of reproduction

Fig. 5A and 5B are flow charts for explaining the operation during regeneration. "regeneration" means, for example, that the components remaining in the trap tube 411 are removed by being desorbed, and the trap tube 411 is regenerated to its original state. When regenerating the trap pipe 411, the

valves

211, 212, 213, and 214 are heated and temperature-adjusted to a predetermined temperature (for example, 150 ℃).

In the regeneration, first, the valve 211 is switched to the open state, and the trap pipe 411 starts to be heated by the heating unit 412. Thereby, the temperature of the trap pipe 411 gradually increases toward the target temperature (e.g., 280 ℃). At this time, the pump 43 is stopped from being driven, and the gas supply from the mixer 44 is also stopped.

When the temperature of the trap pipe 411 reaches the target temperature, the valve 211 is switched to the closed state and the valve 214 is switched to the open state while controlling the heating unit 412 so as to maintain the target temperature. In this state, the carrier gas is supplied from the carrier gas supply portion 5 by controlling the mixer 44. At this time, the standard gas is not supplied from the standard gas supply unit 6.

In this case, as shown by the broken line in fig. 5A, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

104, 109, and 107. Thereby, the component desorbed from trap tube 411 is removed from inside trap tube 411. In this way, in the present embodiment, the carrier gas can be supplied to the concentrator 41 while heating the concentrator 41 (trap pipe 411), and the components remaining in the concentrator 41 can be discharged (regeneration step).

Thereafter, the cooling of trap pipe 411 by cooling unit 413 is started while the supply of the carrier gas from carrier gas supply unit 5 is continued. At this time, the valve 212 is switched to the open state, and the valve 214 is switched to the closed state.

In this case, as shown by the broken line in fig. 5B, the carrier gas supplied from the carrier gas supply unit 5 flows through the

channels

104 and 103. Thus, even after the separation of the component remaining in the trap tube 411 is completed, the flow of the carrier gas indicated by the broken line in fig. 5B is maintained, and therefore the inside of the flow path 103 can be purged.

6. Modification example

In the above embodiment, the case where the detector is the gas chromatograph 2 has been described, but a configuration may be adopted in which a detector other than the gas chromatograph 2 is used to detect the target component. The flow path structure can be arbitrarily changed, and the flow path switching is not limited to the structure using the

valves

211, 212, 213, and 214.

At least a part of the operation at the time of zero point calibration as illustrated in fig. 2A and 2B, the operation at the time of span calibration as illustrated in fig. 3A to 3C, the operation at the time of analysis as illustrated in fig. 4A to 4D, and the operation at the time of regeneration as illustrated in fig. 5A and 5B may be manually performed by an operator, instead of automatic control by the control unit.

7. Means for

It should be understood by those skilled in the art that the various exemplary embodiments described above are specific examples in the following manner.

The gas analysis method according to the first aspect may include:

concentrating the components in the sample gas by using a concentrator;

supplying the concentrated component to a detector by supplying a carrier gas to the concentrator;

supplying the concentrated component to the detector by supplying a carrier gas to the concentrator after concentrating the component in a mixed gas generated by mixing a standard gas with the carrier gas by the concentrator; and

the concentration of the component in the sample gas is measured based on the detection intensity of the component in the sample gas and the detection intensity of the component in the mixed gas in the detector.

According to the gas analysis method described in the first paragraph, the sample gas and the standard gas can be introduced into the concentrator separately, and the standard gas can be diluted with the carrier gas. This eliminates the need for a separate diluter, and thus enables an optimized configuration.

(second item) the gas analysis method according to the first item, wherein,

further comprising the steps of:

supplying the carrier gas to the detector; and

a calibration curve is made based on the detection intensity of the component in the mixed gas and the detection intensity of the component in the carrier gas in the detector,

in the step of measuring the concentration, the concentration of the component in the sample gas is measured based on the detection intensity of the component in the sample gas in the detector and the calibration curve.

According to the gas analysis method described in the second item, a calibration curve can be created based on the detection intensity of the component in the standard gas (component in the mixed gas) diluted with the carrier gas and the detection intensity of the component in the carrier gas, and the concentration of the component in the sample gas can be measured using the calibration curve.

(third) the method for analyzing a gas according to the first or second aspect, wherein the gas is introduced into the reaction chamber,

further comprising the steps of: after the analysis, the carrier gas is supplied to the concentrator to discharge the components remaining in the concentrator.

According to the gas analysis method described in the third aspect, it is possible to prevent the component remaining in the concentrator from adversely affecting the measurement result of the concentration of the component in the sample gas at the time of the next analysis.

The gas analyzer according to the (fourth) aspect may include:

a concentrator for concentrating the sample gas introduced from the sample introduction part;

a detector for detecting components in the sample gas concentrated by the concentrator;

a carrier gas supply unit for supplying a carrier gas;

a standard gas supply unit for supplying a standard gas;

a sample gas flow path that communicates an upstream side of the concentrator with the sample introduction section;

a standard gas flow path that communicates the standard gas supply section with the sample gas flow path at a first confluence section and introduces a standard gas from an upstream side to the concentrator via the sample gas flow path;

a carrier gas flow path which communicates the downstream side of the concentrator with the carrier gas supply unit and introduces the carrier gas from the downstream side into the concentrator;

a pump that is provided downstream of the first merging section and introduces the sample gas or the standard gas from the upstream side into the concentrator;

a flow meter provided downstream of the first merging section and configured to measure a flow rate of the sample gas or a flow rate of the standard gas introduced into the concentrator; and

and a mixer that mixes the standard gas introduced into the concentrator through the standard gas passage with the carrier gas supplied from the carrier gas supply unit.

According to the gas analyzer of the fourth aspect, the sample gas and the standard gas can be introduced into the concentrator, respectively, and the standard gas can be diluted with the carrier gas. This eliminates the need for a separate diluter, and thus enables an optimized configuration.

(fifth item) the gas analyzer according to the fourth item, wherein,

further comprises a lead-out flow path for communicating the upstream side of the concentrator with the detector,

the components in the sample gas or the components in the standard gas concentrated by the concentrator are discharged to the discharge passage by the carrier gas introduced from the carrier gas passage to the downstream side of the concentrator.

According to the gas analyzer of the fifth aspect, after the component in the sample gas and the component in the standard gas are concentrated by the concentrator, the concentrated component can be supplied from the lead-out passage to the detector by the carrier gas introduced into the carrier gas passage.

(sixth item) the gas analyzer according to the fourth or fifth item, wherein,

further comprises an exhaust passage communicating with the carrier gas passage at a second junction,

at least one of the pump and the flow meter is provided in the exhaust passage.

According to the gas analyzer of the sixth aspect, the sample gas introduced from the sample introduction unit can be introduced into the concentrator by driving the pump, and can be discharged through the exhaust passage. By providing at least one of the pump and the flow meter in the exhaust passage, foreign matter and the like can be prevented from being mixed into the concentrator from the pump or the flow meter.

(seventh) the gas analyzer according to any one of the fourth to sixth aspects, wherein,

the mixer can adjust the mixing ratio of the carrier gas with respect to the standard gas.

According to the gas analyzer of the seventh aspect, the standard gas can be diluted at an arbitrary dilution ratio by adjusting the mixing ratio of the carrier gas to the standard gas.

Description of the reference numerals

1: a sample introduction section; 2: a gas chromatograph; 3: a filter; 4: a concentration device; 5: a carrier gas supply unit; 6: a standard gas supply unit; 7: a pump; 40: a housing; 41: a concentrator; 42: a flow meter; 43: a pump; 44: a mixer; 101 to 109, 162, 163: a flow path; 110: a sample gas flow path; 111. 122, 161, 164: a branching section; 120: a lead-out flow path; 121. 171: a confluence section; 130: a standard gas flow path; 140: a carrier gas flow path; 210-214: a valve; 411: a capture tube; 412: a heating section; 413: a cooling section.

Claims

1. A method of gas analysis comprising the steps of:

concentrating the components in the sample gas by using a concentrator;

2. The gas analysis method of claim 1, further comprising the steps of:

supplying the carrier gas to the detector; and

3. The gas analysis method according to claim 1,

4. A gas analyzer is provided with:

a carrier gas supply unit for supplying a carrier gas;

a standard gas supply unit for supplying a standard gas;

5. The gas analysis apparatus according to claim 4,

6. The gas analysis apparatus according to claim 4,

the apparatus further includes an exhaust passage communicating with the carrier gas passage at a second junction, and at least one of the pump and the flow meter is provided in the exhaust passage.

7. The gas analysis apparatus according to claim 4,