JP2000065696A - Filter device and sulfur analytical system provided with filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filter device whose constitution is simple and by which impurities contained in a gas to be analyzed can be removed by a method wherein a filter composed of a blank which does not adsorb sulfur oxide gas is installed on the downstream side of a combustion device. SOLUTION: A filter device 3 is installed in front of a gas dehumidifier 4 on the downstream side of a test-sample combustion device 2. A filter holder 31 which is formed of a heat-resistant fluororesin or the like, a filter 32 which is housed in the holder 31 and a heater 33 which is installed at the outer circumference of the holder 31 so as to be ring-shaped constitute the filter device 3. The filter 32 is formed of a blank which is not reacted with sulfur dioxide gas in a gas to be analyzed and which does not adsorb the sulfur dioxide gas so as to be permeated, e.g. a metal fiber or ceramic fiber fabric, a nonwoven fabric or the like. The heater 33 heats the holder 31 in order to prevent vapor from being condensed at the filter 32. Thereby, impurities such as soot, unsaturated hydrocarbons or the like which are generated due to incomplete combustion are removed, it is possible to prevent the gas dehumidifier 4 and an analyzer 5 from being contaminated, and it is possible to reduce a measuring error.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for purifying an analyte gas obtained by burning a sample, for example, when measuring a sulfur component in the sample using an ultraviolet fluorescence method.
The present invention relates to a filter device, and further to a sulfur analysis system having such a filter device.

[0002]

2. Description of the Related Art An analysis system (sulfur analysis system) is provided with an analyzer using an ultraviolet fluorescence method for quantifying a sulfur component in a sample. Here, the ultraviolet fluorescence method utilizes the fact that when an analyte gas containing a sulfur dioxide gas is irradiated with ultraviolet rays, the sulfur dioxide gas in the analyte gas is excited and emits fluorescence, and the intensity of the fluorescence is measured. It measures the concentration of sulfur dioxide gas in the gas to be analyzed.

[0003] In the analysis system, a sample combustion device for analysis is provided in front of the analyzer in order to change the sulfur component in the sample into sulfur dioxide gas. In addition,
This sample combustion device for analysis converts a sulfur component in a sample into sulfur dioxide gas by burning the sample to generate a gas to be analyzed containing the sulfur dioxide gas.

In the analysis system, the gas to be analyzed generated by the sample combustion device for analysis is introduced into the analyzer via a gas dehumidifier.

[0005]

However, when the sample is incompletely burned by the sample combustion device for analysis, impurities such as soot and unsaturated hydrocarbons are generated, and the gas to be analyzed containing these impurities is generated. Since the gas is introduced into the analyzer through the gas dehumidifier, the soot in the gas to be analyzed contaminates the gas dehumidifier and the analyzer, and the measurement by the analyzer due to unsaturated hydrocarbons in the gas to be analyzed. There is a problem that an error occurs. Note that unsaturated hydrocarbons cause a strong positive error in the ultraviolet fluorescence method.

Therefore, when the sample is incompletely burned in the sample combustion apparatus for analysis, contamination by soot can be solved by disassembling and cleaning the analysis apparatus or replacing gas dehumidifiers and gas pipes. Although such measures are taken, there is a problem that such measures are troublesome and costly. on the other hand,
No effective countermeasures have been taken against measurement errors caused by unsaturated hydrocarbons.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and has a simple configuration so that impurities contained in a gas to be analyzed can be removed without adsorbing sulfur dioxide gas contained in the gas to be analyzed. It is an object of the present invention to provide a filter device and a sulfur analysis system having such a filter device.

[0008]

Therefore, a filter device according to the present invention is a filter device provided downstream of a combustion device that generates a sulfur oxide gas by burning a sulfur analysis sample. And a filter made of a material that does not adsorb the sulfur oxide gas.

Further, the filter device of the present invention is characterized in that the filter is made of silica fiber. Here, the main part of the filter holder is preferably a fluororesin (claim 3), and the fluororesin is more preferably a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (claim 4). ).

Preferably, a heating means for heating the filter device is provided (claim 5). Further, the sulfur analysis system of the present invention comprises a combustion device for burning a sulfur analysis sample to generate a sulfur oxide gas, and a filter holder provided on the downstream side of the combustion device and having a main part made of a fluororesin. And a filter device comprising a filter made of silica fibers housed in the filter holder, and a filter device provided downstream of the filter device and generated by the combustion device introduced through the filter device. The apparatus is characterized in that the apparatus is provided with a sulfur oxide gas analyzer for irradiating the sulfur oxide gas with ultraviolet rays from an ultraviolet light source to measure a sulfur component in the sulfur oxide gas.

The sulfur analysis system according to the present invention is characterized in that the fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (claim 7).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but are not limited to the following description without departing from the gist of the invention. FIG. 1 is a block diagram illustrating a configuration of a sulfur analysis system having a filter device according to an embodiment of the present invention, and FIG. 7 is a functional block diagram illustrating a configuration of the sulfur analysis system.

This sulfur analysis system (hereinafter simply referred to as an analysis system) 1 measures the content of a sulfur component in an analysis sample (sulfur analysis sample) using an ultraviolet fluorescence method. As shown in FIG.
The apparatus includes a filter device 3, a gas dehumidifier 4, and an analyzer (sulfur dioxide gas analyzer) 5. Here, the sample burning device for analysis 2 according to the present embodiment burns a sample containing a sulfur component to generate an analyte gas containing a sulfur dioxide gas in which the sulfur component in the sample has changed, In addition to a sample combustion section 11 consisting of a reaction section 6 and a heater (heating section) 7, a gas purifier 8A, 8
B, gas flow meters 9A to 9C and a gas switching valve 10.

The reaction section 6 is configured as a quartz glass reaction tube for generating a gas to be analyzed by burning a sample, and includes an inner pipe (first reaction section) 62 and an outer pipe (second reaction section). ) 63. The inner tube 62 generates a sample gas by partially vaporizing and thermally decomposing the sample introduced therein, and is connected to the analysis sample introduction unit 61 and the inert gas introduction unit 62A. The sample is introduced through an inert gas introduction section 62.
An inert gas (carrier gas) such as an argon gas is introduced through A.

In the present embodiment, the sample is placed on the sample boat 65 and introduced into the inner tube 62. However, the sample can be injected into the inner tube 62 using a syringe or the like.
A sample introduction tube for introducing a sample may be connected to the inner tube 62 to inject a sample from the sample introduction tube. In the present embodiment, the sample after the thermal decomposition is completely burned in the inner tube 62.

The outer tube 63 burns the sample gas generated in the inner tube 62. The outer tube 63 is provided so as to include the inner tube 62 on the outer periphery of the inner tube 62. Oxygen gas is introduced through an introduction section 63B. In addition, quartz wool 64 for accelerating the reaction is provided in the outer tube 63. That is, the inner tube 6
2 is partially inserted into the outer tube 63 such that the outer end opening 62C is located inside the outer tube 63. In other words, the outer tube 63 communicates with the inner tube 62 and It is provided adjacent to and connected to the oxygen gas introduction part 63B.

Further, the heater 7 constitutes an annular electric furnace for heating the reaction section 6 to set it in a high-temperature atmosphere, and mainly comprises a pre-stage for applying heat for generating a sample gas to the inner tube 62. It is composed of a heater 7A and a rear-stage heater 7B that mainly supplies heat for burning the sample gas to the outer tube 63, and the front-stage heater 7A and the rear-stage heater 7B cooperate to apply heat to the reaction unit 6. ing.

In this embodiment, the set temperature of the first-stage heater 7A is about 800 ° C., and the set temperature of the second-stage heater 7B is about 1000 ° C. The heater 7 is usually provided on the outer periphery of the reaction section 6 as in the present embodiment, but may be provided on the entire outer periphery or on a part of the outer periphery.
Further, the heater 7 may be provided inside the reaction section 6.

On the other hand, the gas purifier 8A purifies the inert gas supplied to the reaction section 6, and the gas purifier 8B
Is for purifying the oxygen gas supplied to the reaction section 6. Further, the gas flow meter 9A adjusts the flow rate of the inert gas purified by the gas purifier 8A, and the gas flow meters 9B and 9C control the flow rate of the oxygen gas purified by the gas purifier 8B. Is to adjust. In this embodiment,
In order to enable the supply flow path of the oxygen gas to be switched by the gas switching valve 10 described later, the gas flow meters 9B and 9 for the oxygen gas are used.
C is provided and the oxygen gas flow path is divided into two.

As an example, when the flow rate of the inert gas introduced into the reaction section 6 is 400 mL / min and the flow rate of the oxygen gas introduced into the reaction section 6 is 600 mL / min, the gas flow meter 9 A 400 mL of active gas flow
/ Min, and gas flow meters 9B and 9C
Are adjusted so that the flow rate of oxygen gas is 300 mL / min.

The gas switching valve 10 is provided with a gas flow meter 9B.
The supply path of the oxygen gas is switched so as to supply the oxygen gas from the supply port to the oxygen gas introduction section 63B of the outer pipe 63 and the oxygen gas supply section 62B of the inner pipe 62. In other words, the gas switching valve 10 functions as an oxygen-containing gas supply switching unit that can supply a part of the oxygen gas supplied to the outer pipe 63 to the inner pipe 62.

That is, in the sample burning device for analysis 2 of this embodiment, when the sample is pyrolyzed in the inner tube 62, the oxygen gas supplied from the gas flow meter 9B is supplied to the gas switching valve 10
The oxygen gas is supplied to the outer tube 63 through the oxygen gas inlet 63B (see FIG. 1). However, when the pyrolyzed sample is completely burned in the inner tube 62, the gas switching valve 10 is used.
To switch the flow path of the oxygen gas to supply the oxygen gas (a part of the oxygen gas supplied to the outer tube 63) supplied from the gas flow meter 9B to the gas switching valve 10 and the oxygen gas introduction section 62B.
Through the inner tube 62.

In the present embodiment, after the gas switching valve 10 is switched, a part of the oxygen gas is introduced into the inner tube 62 in order to quickly introduce the oxygen gas into the inner pipe 62. A part of the oxygen gas can be supplied to the inner pipe 62 by being introduced from the gas introduction part 62B. As a result of intensive studies, the present inventors have found that when the oxygen gas concentration in the gas to be analyzed fluctuates, the baseline of the analyzer 5 fluctuates (that is, noise is generated in the output of the analyzer 5). Was.

Therefore, in the present embodiment, in order to keep the oxygen gas concentration at the time of burning the sample constant, the flow path of the oxygen gas is switched by the gas switching valve 10 so that the oxygen gas from the gas flow meter 9B is supplied. By mixing with the inner pipe 62 through the oxygen gas introduction part 62B, the total flow rate and the flow rate ratio of the oxygen gas and the inert gas are not changed.

That is, in the above-described example, when the sample is thermally decomposed in the inner tube 62, the flow rate of 400
While supplying the inert gas of mL / min to the inner tube 62,
As shown in FIG. 1, the position of the gas switching valve 10 is set so that the oxygen gas from the gas flow meter 9B merges with the oxygen gas from the gas flow meter 9C, and the flow rates of the gas flow meters 9B and 9C are 300 mL, respectively. / Min oxygen gas is supplied to the outer tube 63.

When the pyrolyzed sample is completely burned in the inner tube 62, an inert gas having a flow rate of 400 mL / min is supplied from the gas flow meter 9A to the inner tube 62, while the gas flow meter 9A is used. The gas switching valve 10 is switched so that oxygen gas from 9B is introduced into the oxygen gas introduction section 62B, and oxygen gas at a flow rate of 300 mL / min is further supplied from the gas flow meter 9B to the inner pipe 62, and the gas flow meter 9
An oxygen gas at a flow rate of 300 mL / min is supplied to the outer tube 63 from C.

As described above, in this embodiment, since a part of the oxygen gas supplied to the outer pipe 63 is supplied to the inner pipe 62, the total flow rate and the flow rate ratio of the oxygen gas and the inert gas are reduced. It can be kept unchanged. By the way, the filter device 3 according to the present embodiment removes impurities (such as soot and unsaturated hydrocarbons generated by incomplete combustion) contained in the analyte gas generated by the sample combustion device for analysis 2, It is for purifying the gas to be analyzed, and is provided between the gas dehumidifier 4 and the sample combustion device 2 for analysis downstream of the sample combustion device 2 for analysis.

Here, the filter device 3 is provided with a filter holder 31, a filter 32 and a heater (heating means) 33 as shown in FIG. In addition,
FIG. 4 shows a perspective view of the filter holder 31 and the filter 32. The filter holder 31 holds the filter 32, and its main part is made of a heat-resistant material (preferably, a fluororesin).

Here, as the fluorine resin, for example,
Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride And polyvinyl fluoride. Among them, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) is preferable.

The filter holder 31 may be made of metal or ceramic as long as it does not adsorb sulfur dioxide gas. Also, the filter 32
A material that allows components other than the above impurities in the analyte gas to pass therethrough, is contained in the filter holder 31, does not react with the sulfur dioxide gas in the analyte gas, and is made of a material that does not adsorb the sulfur dioxide gas. It is.

Here, such a material is usually
A woven fabric of a metal fiber or a ceramic fiber, a non-woven fabric of a metal fiber or a ceramic fiber, and the like can be given. In particular, a silica fiber containing no alumina binder is preferable. Further, in the present embodiment, it is necessary to use a filter having a density capable of removing 95% or more of fine particles of 0.3 μm or more.

Further, the heater 33 heats the filter holder 31 in order to prevent condensation of water vapor in the filter 32, and is provided on the outer periphery of the filter holder 31 in an annular shape. Note that, in the present embodiment, as the heater 33, while holding the filter holder 31, 110 to 15
A pipe mantle heater capable of keeping the temperature at about 0 ° C. was used.

In order to determine the materials of the filter 32 and the filter holder 31, the present inventors constructed a filter device by combining various filters and various filter holders, and adsorbed sulfur dioxide gas in these filter devices. And the reproducibility of the signal were tested, and the following results were obtained. In the following, the analyte gas generated by burning the sulfur-containing standard sample is supplied to the analyzer 5 through these filter devices, and the peak shape and the baseline are measured by the analyzer 5, and no filter device is provided. It is a comparison with the peak shape and the baseline in the case.

[0034]

[Table 1]

Teflon is a registered trademark representing tetrafluoroethylene. Here, two types of filters were tested for a composite membrane of a fluororesin and glass fiber, a Teflon membrane, a borosilicate glass membrane, and a silica fiber membrane. In the case of a composite membrane of a fluororesin and glass fiber, it was judged to be unsuitable because the adsorption of sulfur dioxide gas was severe. In addition, the Teflon membrane and the borosilicate glass membrane were judged to be unsuitable, respectively, because it is considered that sulfur dioxide gas was adsorbed from the point that the signal reproducibility was poor and the analysis value was too small. Further, the silica fiber membrane containing the alumina binder seemed to slightly react with and adsorb to the sulfur dioxide gas, but the silica fiber membrane not containing the alumina binder did not adsorb the sulfur dioxide gas, so that good results were obtained. .

The filter holder is made of polypropylene (PP), stainless steel (SUS), PFA
The product made from PFA was tested, but if the product made from PFA was heated and used, there was no problem in the analytical value. Therefore, the present inventors have found from the above results that PF having heat resistance and chemical resistance
The combination of a filter holder made of A and a filter made of silica fiber that does not adsorb sulfur dioxide (does not contain an alumina binder) has the least effect on the adsorption of sulfur dioxide gas and the reproducibility of signals, and is effective. I found it.

When the incomplete combustion was caused in the sample combustion device 2 for analysis using the filter device 3 of the above specification, the signal change was observed. After the replacement of the contaminated filter device 3, about 1. It returned to its original low baseline in 5 hours. Conventionally, the baseline was not restored unless it was decomposed and washed. It is considered that the reason why the baseline is gradually recovered is that the disturbing gas components and the like that have passed through the filter device 3 adhere to the piping system, and it takes time to replace the piping system.

There is no general analysis system (sulfur analysis system) 1 in which a filter device 3 is provided between an analysis sample combustion device 2 and an analysis device 5. The gas dehumidifier 4 removes moisture contained in the gas to be analyzed from the sample combustion device for analysis 2. Further, the analyzer 5 is provided on the downstream side of the filter device 3 and the gas dehumidifier 4, and when the analyte gas generated by the sample combustion device for analysis 2 is introduced through the filter device 3 and the gas dehumidifier 4, The concentration of the sulfur dioxide gas contained in the gas to be analyzed is measured.

FIG. 5 shows the structure of the analyzer 5. Here, the analyzer 5 includes an ultraviolet irradiation light source unit 55 and a measurement cell unit 56, as shown in FIGS. The ultraviolet irradiation light source section 55 has a built-in ultraviolet irradiation light source for irradiating ultraviolet rays. Specifically, the ultraviolet irradiation light source section 55 includes a light source section 51 and a spectral cell section 52.

The light source 51 includes a light source 51A such as a xenon lamp and a condenser lens 51B in a cylindrical casing 51C. In addition, the spectroscopic cell unit 52 preferably incorporates filters 52A and 52B that reflect ultraviolet rays having a wavelength of 200 to 240 nm in a rectangular parallelepiped casing 52C, thereby extracting ultraviolet rays from light from the light source unit 51 and measuring cells. The light is emitted to the unit 56.

As shown in FIG. 6, the casing 52C comprises a frame member 52b and lid members 52a and 52c, and the filters 52A and 52B have a casing 52C as shown in FIG. The light source unit 51 is disposed at an angle of about 45 ° with respect to the optical path through which the light from the light source unit 51 passes. Further, as shown in FIGS. 5 and 6, the light source unit 51 has a wall surface (a light passing unit P through which light from the light source 51A passes) connected to the spectral cell unit 52 of the casing unit 51C.
A pair of openings H1 and H2 are formed at positions opposite to the cylindrical wall surface W2 other than the wall surface W1 of the casing portion 51C formed with No. 1. In the present embodiment, the openings H1 and H2 are formed in the vicinity of the spectroscopic cell section 52 on the cylindrical wall surface W2.

As shown in FIGS. 5 and 6, the spectroscopic cell section 52 has a wall surface (a light passing section P2 through which light from the light source section 51 passes) connected to the light source section 51 of the casing section 52C.
Is formed on the wall of the casing portion 52C) and the wall connected to the measurement cell portion 56 of the casing portion 52C (the light passing portion P3 through which the ultraviolet light obtained by the spectroscopic cell portion 52 passes).
Are formed on the opposite wall surfaces W5 and W6 of the wall surfaces other than W4).
3, H4 are formed.

Here, the openings H1 and H2 are connected to the light source 51.
The openings H3 and H4 are provided for ventilation of the internal gas of the casing portion 52C of the spectroscopic cell portion 52. Since air is present in the casings 51C and 52C of the light source unit 51 and the spectroscopic cell unit 52, oxygen gas contained in the air absorbs ultraviolet rays for exciting the sulfur dioxide gas, while oxygen that has absorbed the ultraviolet rays. The gas changes to ozone gas, and this ozone gas also absorbs ultraviolet rays. Therefore, if the analyzer 5 is used as it is, the intensity of the ultraviolet rays incident on the measurement cell unit 56 will decrease. In particular, when the concentration of the ozone gas increases with the passage of time, the intensity of the ultraviolet light continuously decreases.

As described above, when the intensity of the ultraviolet ray for exciting the sulfur dioxide gas changes, the intensity of the fluorescent light generated from the gas to be analyzed also changes. Become. Therefore, in the present embodiment, in order to reduce the internal retention of the ozone gas generated by the ultraviolet rays, the openings H1 and H2 are provided on the wall surface W2 of the casing 51C, while the openings H3 and H2 are provided.
4 is provided on the wall surfaces W5 and W6 of the casing portion 52C, and the inside gas of the casing portions 51C and 52C is ventilated by venting and replacing with an inert gas or the atmosphere.

Here, in the case where the gas is replaced by the inert gas, one of the openings H1 and H2 of the casing 51C (or the openings H3 and H4 of the casing 52C) is provided. For example, an inert gas cylinder (not shown) for supplying an inert gas is connected, the inert gas from the inert gas cylinder is introduced into the casing 51C (or the casing 52C), and the exhaust gas is exhausted from the other opening. In this case, the internal gas of the casing 51C (or the casing 52C) may be forcibly ventilated.

When the air is replaced by air,
For example, a blower is connected to one of the openings H1 and H2 of the casing portion 51C (or the opening portions H3 and H4 of the casing portion 52C), and the wind from the blower is sent to the casing portion 51C (or Into the casing part 52C) and exhaust air through the other opening.
What is necessary is just to comprise so that the internal gas of 1C (or casing part 52C) may be forcibly ventilated.

When the air is replaced by air,
Without using a blower or the like, the opening portions H1 and H2 of the casing portion 51C (or the opening portions H3 and H3 of the casing portion 52C).
H4) may be opened to the atmosphere so that the gas inside the casing 51C (or the casing 52C) is naturally ventilated. That is, the analyzer 5 in the present embodiment
In the above, the ventilation means for ventilating the internal gas is configured to include openings H1 to H4 formed in the casing parts 51C and 52C of the ultraviolet light source 55, When an inert gas cylinder or a blower is attached to the device 5, it is configured as a forced ventilation means for the internal gas, and when the openings H1 to H4 are opened to the atmosphere, it serves as a natural ventilation means for the internal gas. Will be composed.

On the other hand, the measuring cell section 56 irradiates the gas to be analyzed with ultraviolet rays from the ultraviolet light source 55 to measure the components in the gas to be analyzed (measure the concentration of sulfur dioxide gas). More specifically, as shown in FIGS. 1, 5, and 7, it is configured to include a cell 53, a photodetector 54, and a controller 57 (see FIG. 7). The cell 53 is for irradiating the gas to be analyzed with ultraviolet rays to generate fluorescence in the sulfur dioxide gas, and has a condenser lens (not shown) and a space for generating fluorescence in the sulfur dioxide component. Cell body 53A, gas inlet 5 for introducing gas to be analyzed
3B, a gas outlet 53C for discharging the gas to be analyzed.

The light detecting section 54 detects the fluorescence generated in the cell 53, performs photoelectric conversion, and generates an electric signal corresponding to the intensity of the fluorescence, and includes a condenser lens (not shown), Photomultiplier tube (PMT)
) 54A and a filter 54B for extracting fluorescence. The filter 54B is an optical filter that can selectively transmit only the wavelength of preferably 300 to 400 nm among the fluorescent wavelengths unique to the sulfur dioxide gas.

Further, the control section 57 amplifies the electric signal obtained by the light detection section 54. With the above-described configuration, in the analysis system 1 having the filter device 3 according to one embodiment of the present invention, when a sample to be measured is introduced into the analysis sample combustion device 2, the analysis sample combustion device 2 By burning this sample, an analyte gas containing sulfur dioxide gas is generated.

The analyte gas generated by the sample combustion device for analysis 2 is introduced into the analyzer 5 through the filter device 3 and the gas dehumidifier 4. At this time, the filter device 3 removes soot and the like contained in the gas to be analyzed, and the gas dehumidifier 4 removes moisture contained in the gas to be analyzed.
Then, in the analyzer 5, the concentration of the sulfur dioxide gas in the introduced analyte gas is measured, and the measured analyte gas is discharged from the analyzer 5.

Here, the combustion processing of the sample in the sample burning device for analysis 2 will be described. First, in the sample burning device for analysis 2, the inner pipe 62 of the reaction section 6 of the sample burning portion 11 is used.
In this state, the sample and the inert gas are introduced, and the outer tube 63 is introduced with the oxygen gas.
For example, in the example described above, the gas flow meter 9A is attached to the inner pipe 62.
A gas flow meter 9B, 9C is supplied to the outer pipe 63 through the gas switching valve 10 in a state as shown in FIG.
From which oxygen gas having a total flow rate of 600 mL / min is introduced.

Then, the reaction section 6 is heated by the heater 7 to make the inside of the reaction section 6 a high-temperature atmosphere, and the sample is partially vaporized and thermally decomposed by the high-temperature atmosphere in the reaction section 6 to thereby decompose the sample in the inner tube 62. A sample gas is generated from the sample. Further, in the inner tube 62, the sample gas is transported into the outer tube 63 by continuing to introduce the inert gas, and in the outer tube 63, the transported sample gas is transported by the oxygen gas in the outer tube 63. Burn (the above is the first step).

Thereafter, the gas switching valve 10 is switched to supply the inner pipe 62 with the inert gas and also supply the oxygen gas from the gas flow meter 9 B which is supplying the outer pipe 63 with the inner pipe 62. The sample combustion in the inner tube 62 is promoted to completely burn the sample in the inner tube 62 (second step). For example, in the above-described example, by switching the gas switching valve 10, the inner pipe 62 has a flow rate of 400 m from the gas flow meter 9A.
In addition to the L / min inert gas introduced, an oxygen gas at a flow rate of 300 mL / min from the gas flow meter 9B is also introduced.
The sample is completely burned in the inner tube 62 by introducing oxygen gas at 0 mL / min.

Finally, in the sample burning device for analysis 2, the gas switching valve 10 is switched again to supply the oxygen gas from the gas flow meter 9 B to the inner pipe 62 in preparation for the generation of the gas to be analyzed for the next sample. While the supply is stopped, the oxygen gas is supplied to the outer tube 63, and the state of introduction of the inert gas into the inner tube 62 and the state of introduction of the oxygen gas into the outer tube 63 are respectively the initial states (the above-described first state). (The same state as one step) (third step). For example, in the example above,
By switching the gas switching valve 10 again to return to the state shown in FIG. 1, the inner pipe 62 is returned to a state in which only the inert gas with a flow rate of 400 mL / min from the gas flow meter 9A is introduced. Gas flow meter 9B, 9C
Is returned to a state where oxygen gas with a total flow rate of 600 mL / min is introduced.

In this way, the flow ratio between the oxygen gas and the inert gas supplied to the entire reaction section 6 in the second step is supplied to the entire reaction section 6 in the first and third steps. It can be set to the same value as the flow ratio of the oxygen gas and the inert gas to be performed, and the change in the total flow rate and the mixing ratio of the oxygen gas and the inert gas can be minimized.

When the sample for analysis is burned, oxygen gas is separately supplied to the inner tube 62 as in the prior art [FIG.
FIG. 3 (a) schematically shows this]. As shown in FIG. 3 (b), although the baseline of the analyzer 5 fluctuates, the oxygen gas supplied to the outer tube 63 as in this embodiment is changed. Is supplied to the inner tube 62 (this is schematically shown in FIG. 2A), it is possible to reduce the fluctuation of the baseline of the analyzer 5 as shown in FIG. 2B. it can.

As described above, according to the sample burning device for analysis 2 of the present embodiment, the gas switching valve 10 is provided and the inner pipe 6 is provided.
Since the gas switching valve 10 is switched when the sample is burned in the inside 2, a part of the oxygen gas supplied to the outer tube 63 is supplied to the inner tube 62 in addition to the supply of the inert gas. The gas flow path to the reaction section 6 can be switched without changing the total flow rate and the mixing ratio of the gas and the inert gas.
Therefore, it is possible to prevent a change in the oxygen gas concentration in the gas to be analyzed, thereby preventing a change in the baseline in the analyzer 5, and to accurately measure the sulfur component even when the sample contains a trace amount of the sulfur component.

Further, in this sample combustion apparatus for analysis 2, when a part of the oxygen gas supplied to the outer tube 63 is supplied to the inner tube 62 by switching the flow path, a part of the oxygen gas is supplied to the sample. Since the oxygen gas is introduced from the oxygen gas introduction part 62B provided downstream of the introduction part 61A, the oxygen gas is quickly introduced into the inner pipe 62 to shorten the time during which only the inert gas flows through the inner pipe 62. can do. On the other hand, when the gas to be analyzed generated by the sample combustion device for analysis 2 as described above passes through the filter device 3, impurities such as soot contained in the gas to be analyzed are removed by the filter 32.

At this time, in the filter device 3, the heater 3
3, the filter holder 31 is kept at a temperature of about 110 to 150 ° C., so that condensation of water vapor in the filter 32 can be prevented. As described above, according to the filter device 3 according to the present embodiment, the impurities contained in the gas to be analyzed can be removed without adsorbing the sulfur dioxide gas contained in the gas to be analyzed. In addition to preventing the gas dehumidifier 4 and the analyzer 5 from being contaminated, measurement errors in the analyzer 5 can be reduced.

Accordingly, the time required for the baseline recovery in the analyzer 5 can be shortened, the labor required for the baseline recovery can be reduced, the maintenance of the analyzer 5 can be facilitated, and the gas dehumidifier 4 and the gas piping can be used. It is no longer necessary to replace the battery, so that the cost for replacement can be reduced. And the measurement in the analyzer 5 can be performed with high accuracy.

In the present embodiment, the filter device 3 having a shape as shown in FIGS. 1 and 4 is used, but another shape (for example, a column shape) may be used. Further, the gas to be analyzed purified by the filter device 3 is introduced into the analyzer 5 after the moisture is removed when passing through the gas dehumidifier 4. Here, the measurement processing of the gas to be analyzed in the analyzer 5 will be described. First, in the ultraviolet irradiation light source unit 55, when the light from the light source unit 51 is irradiated to the spectral cell unit 52, the spectral cell unit 52 , Filter 5
The ultraviolet rays in the light are reflected at 2A and 52B to select the ultraviolet rays, and the selected ultraviolet rays are measured.
6 is emitted.

At this time, in the light source section 51, the apertures H1,
The gas inside the casing portion 51C is ventilated through H2, and the opening portions H3, H4
The ventilation of the internal gas of the casing part 52C is performed through. When ventilating the inside gas of the casing portions 51C and 52C and replacing the ventilation with an inert gas, the opening portions H1 and H2 of the casing portion 51C (or the opening portions H3 and H4 of the casing portion 52C). An inert gas is introduced into the casing 51C (or the casing 52C) from one of the openings by, for example, an inert gas cylinder (not shown), and the other opening is used to exhaust gas.
The gas inside the casing 51C (or the casing 52C) is forcibly ventilated.

When the air is replaced by air,
For example, a blower blows wind from one of the openings H1 and H2 of the casing 51C (or the openings H3 and H4 of the casing 52C) to the casing 51C.
(Or the casing 52C), and exhaust is performed through the other opening to forcibly ventilate the gas inside the casing 51C (or the casing 52C).

When the air is replaced by air,
Without using a blower or the like, the opening portions H1 and H2 of the casing portion 51C (or the opening portions H3 and H3 of the casing portion 52C).
H4) may be opened to the atmosphere to naturally ventilate the gas inside the casing 51C (or the casing 52C). In this state, when the gas to be analyzed is introduced from the gas dehumidifier 4 into the measurement cell section 56, the sulfur dioxide gas in the gas to be analyzed is excited by ultraviolet rays in the cell 53 of the measurement cell section 56, and the fluorescence is emitted. appear. Then, the fluorescence generated in the cell 53 is detected by the PMT 54A of the light detection unit 54, and is converted into an electric signal according to the fluorescence intensity.
The electric signal obtained by the light detection unit 54 is transmitted to the control unit 5
After being amplified at 7, the waveform is processed, and the analysis result of the sulfur component in the gas to be analyzed is obtained.

As described above, according to the analyzer 5 of this embodiment, the ultraviolet light source 55 (that is, the light source 51)
Further, since the opening portions H1 to H4 are provided in the spectral cell portion 52) to ventilate the internal gas, the internal retention of the ozone gas can be reduced, and the change in the ultraviolet intensity can be reduced or prevented. Therefore, the accuracy of the analysis value can be improved, and also, as shown in FIG. 8, daily fluctuation of the analysis value can be prevented (see ● in FIG. 8). In addition, FIG.
FIG. 9 is a diagram showing the diurnal variation of the analysis value of the gas to be analyzed generated by burning the sulfur-containing standard sample. In FIG. 8, the analysis values when the apertures H1 to H4 are not provided in the ultraviolet light source 55 are shown. The analysis value when the opening portions H1 to H4 are provided in the ultraviolet irradiation light source unit 55 is indicated by ○, and the analysis value is indicated by ●.

Further, since the apertures H1 and H2 are formed in the vicinity of the spectroscopic cell section 52 of the light source section 51, the internal stagnation of ozone gas can be effectively reduced. In the analyzer 5 according to the present embodiment, the openings H1 and H2 are
It is formed in the vicinity of the spectroscopic cell portion 52 of the cylindrical wall surface W2 so as to face in the horizontal direction as shown in FIG.
It may be formed so as to be opposed in the vertical direction. The openings H1 and H2 may be formed at positions near the wall surface W2.

In this embodiment, the opening portions H3, H4
Is the wall surface W3 formed with the light passing portion P2 and the light passing portion P
3 are formed on opposing wall surfaces W5 and W6 of the wall surfaces other than the wall surface W4 on which the holes 3 are formed.
As long as it is a wall surface other than the wall surfaces W3 and W4, it may be formed on the wall surfaces other than the opposing wall surfaces W5 and W6, or may be formed on the same wall surface.

Further, in the present embodiment, the apertures H1 and H2 are formed in the light source 51 of the analyzer 5 and the apertures H3 and H4 are formed in the spectroscopic cell 52.
The openings H1 and H2 may be formed only in the light source unit 51, or the openings H3 and H4 may be formed only in the spectral cell unit 52.
In the present embodiment, the light source 51 has a pair of apertures H.
1 and H2 are formed, and a pair of openings H3 and H4 are formed in the spectroscopic cell unit 52, but a single unpaired opening may be formed.

Further, in the analyzer 5 of the present embodiment, the filters 52A and 52B
Although a reflection-type optical filter is used as an example, a transmission-type optical filter may be used. In addition, in the analysis system 1 shown in FIG. 1, a general analysis sample combustion device that does not include the gas switching valve 10 can be used as the analysis sample combustion device 2. Analysis system 1
, The gas dehumidifier 4 may not be provided.

Further, in the analysis system 1, the opening H 1 as described in the present embodiment is used as the analyzer 5.
A general analyzer having no H4 can be used.

[0072]

As described in detail above, according to the present invention,
Since the impurities contained in the gas to be analyzed can be removed without adsorbing the sulfur dioxide gas contained in the gas to be analyzed, it is possible to prevent the gas dehumidifier and the analyzer provided at the subsequent stage from being contaminated. Has the advantage of being able to
There is an advantage that a measurement error in the analyzer can be reduced. Therefore, it is possible to reduce the labor required for the restoration of the baseline, to facilitate the maintenance of the analyzer, to reduce the cost of replacing the gas dehumidifier and the gas piping, and to improve the accuracy of the measurement by the analyzer. It can be carried out well (claims 1-4, 6, 7).

Further, according to the filter device of the present invention, since the heating means for heating the filter device is provided, there is an advantage that the condensation of water vapor on the filter can be prevented (claim 5).

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a sulfur analysis system having a filter device according to one embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating an oxygen gas supply method used in the sample combustion apparatus for analysis according to one embodiment of the present invention.

FIGS. 3A and 3B are diagrams illustrating an oxygen gas supply method used in a general analytical sample combustion apparatus.

FIG. 4 is a perspective view showing a configuration of a filter device according to one embodiment of the present invention.

FIG. 5 is a diagram schematically showing a configuration of an analyzer according to one embodiment of the present invention.

FIG. 6 is a perspective view showing a configuration of a light source unit and a spectral cell unit.

FIG. 7 is a functional block diagram showing a configuration of a sulfur analysis system having a filter device according to one embodiment of the present invention.

FIG. 8 is a diagram showing an effect of reducing daily fluctuation of an analysis value by the analyzer according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 analysis system (sulfur analysis system) 2 sample combustion device for analysis 3 filter device 4 gas dehumidifier 5 analyzer 6 reaction unit 7 heater (heating unit) 7A front stage heater 7B rear stage heater 8A, 8B gas purifier 9A to 9C gas flow rate Total 10 Gas switching valve (oxygen-containing gas supply switching means) 11 Sample burning part 31 Filter holder 32 Filter 33 Heater (Heating means) 51 Light source part 51A Light source 51B Condensing lens 51C Casing part 52 Spectral cell part 52A, 52B Filter 52C Casing Unit 53 Cell 53A Cell body 53B Gas inlet 53C Gas outlet 54 Light detector 54A Photomultiplier tube 54B Filter 55 Ultraviolet irradiation light source unit 56 Measurement cell unit 57 Control unit 61 Sample introduction unit 62 Inner tube (first reaction unit) 62A Inert gas introduction section 62B Oxygen gas introduction Part 62C Outer end opening 63 Outer tube (second reaction part) 63B Oxygen gas introduction part (oxygen-containing gas introduction part) 64 Quartz wool 65 Sample boat H1 to H4 Opening part P1 to P3 Light passing part W1 to W6 Wall surface

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshio Kaneko 1000 Kamoshitacho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 2G042 AA01 BA08 DA04 DA09 EA02 HA07 HA10 2G043 AA01 BA07 DA01 DA02 EA01 GA06 GA14 HA01 JA01 KA03 LA02

Claims (7)

[Claims] 1. A filter device provided downstream of a combustion device for producing a sulfur oxide gas by burning a sulfur analysis sample, comprising: a filter holder; and a filter made of a material that does not adsorb the sulfur oxide gas. A filter device comprising: 2. The filter device according to claim 1, wherein said filter is made of silica fiber. 3. The filter device according to claim 1, wherein a main part of the filter holder is made of a fluororesin. 4. The filter device according to claim 3, wherein said fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. 5. The filter device according to claim 1, further comprising heating means for heating the filter device. 6. A combustion device for producing a sulfur oxide gas by burning a sample for sulfur analysis, a filter holder provided on the downstream side of the combustion device and having a main part made of fluororesin, and the filter holder A filter device comprising a filter made of silica fibers housed therein; and an ultraviolet ray provided to the sulfur oxide gas generated by the combustion device provided downstream of the filter device and introduced through the filter device. A sulfur analysis system having a filter device, comprising: a sulfur oxide gas analyzer for irradiating ultraviolet rays from an irradiation light source unit to measure a sulfur component in the sulfur oxide gas. 7. The sulfur analysis system having a filter device according to claim 6, wherein the fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.