JPS6120804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dehumidifying device for a gas analyzer in which a sample gas is passed through a semi-permeable membrane type gas phase dehumidifier and then introduced into the gas analyzer.

Generally, when using a gas analyzer to investigate the composition of a gas, it is desirable that the amount of water vapor, moisture, etc. contained in the sample gas to be measured introduced into the gas analyzer is as small as possible. For example, chemiluminescent
In the case of NOx analyzers, contamination of the reaction cell window is reduced and span drift is reduced, and in the case of infrared analyzers, contamination of the sample cell inner wall window is reduced and normal This results in a reduction in zero drift.

To this end, heating conduits are typically used to prevent the formation of condensed water, and a dehumidifier is used to remove moisture from the sample gas before introducing the dry sample gas into the gas analyzer. Furthermore, in the case of an SO ₂ gas analyzer, the gas conduit leading to the dehumidifier is heated above the condensation point of SO ₂ because SO ₂ easily dissolves in the drain. However, if the distance from the sampling point of the measurement gas to the dehumidifier becomes long, the power consumption for heating the conduit increases and it is difficult to perform uniform heating.

In order to solve these problems, the present applicant previously provided a gas analyzer as shown in FIG.
According to this device, a sample gas containing water vapor enters a gas sampling device 2 through a gas extraction pipe 1 and is introduced into a semipermeable membrane gas phase dehumidifier 4 through a conduit 3. The sample gas dried by this dehumidifier 4 is introduced into a gas analyzer 6 through a conduit 5, and then exhausted through a gas exhaust conduit 7. The pressure is reduced through a total of 9, and the semi-permeable membrane gas phase dehumidifier 4
is supplied as a dry purge gas. This dry purge gas is then sucked out from the dehumidifier 4 through the exhaust conduit 10 by the suction pump 11 and released into the atmosphere.

However, in this conventional device, the pressure of the sample gas within the analyzer changes as the suction capacity of the suction pump 11 increases or decreases, which causes an error in the readings of the analyzer.

Therefore, an object of the present invention is to minimize the pressure fluctuation of the sample gas inside the gas analyzer, and to provide a semi-permeable membrane vapor phase dehumidifier for the sample gas that is dried by the dehumidifier and discharged from the gas analyzer. An object of the present invention is to provide a dehumidifying device for a gas analyzer that can be supplied as a dry purge gas.

However, in order to achieve this purpose,
The present invention is a dehumidifying device for a gas analyzer of the type mentioned at the beginning, in which a part of the gas discharged from the gas analyzer is introduced into the gas phase dehumidifier as dry purge gas, and the gas discharged from the gas analyzer is It is characterized by being configured so that the remainder is released into the atmosphere.

According to the present invention, the pressure of the sample gas in the gas analyzer can be maintained at approximately atmospheric pressure.

According to one advantageous embodiment of the present invention, the gas exhausted from the gas analyzer is exhausted into an atmosphere-opening tube whose one end is open to the atmosphere, and a part of this exhausted gas is used as dry purge gas. .

According to another embodiment of the invention, the vapor phase dehumidifier is provided in multiple stages, and the dry purge gas is introduced into the first stage of the vapor phase dehumidifier.

According to still another embodiment of the present invention, the gas phase dehumidifier is provided in multiple stages, and the gas exhausted from the gas analyzer is introduced into the final stage gas phase dehumidifier as a dry purge gas, and then the gas is introduced into the atmosphere-opening pipe. is exhausted.

Embodiments of the dehumidifying device for gas analyzers according to the present invention will be described below with reference to FIGS. 2 to 5.

FIG. 2 shows an embodiment of the dehumidifying device for a gas analyzer according to the present invention. In the figure, a sample gas containing water vapor enters a gas sampling device 2 through a gas extraction pipe 1, passes through a conduit 3, and enters a first gas phase. It is introduced into the dehumidifier 4. The sample gas dried by the first gas-phase dehumidifier 4 is sucked out by the first suction pump 13 through the filter 12, and is divided along the way.
A portion of the sample gas is introduced into the second gas phase dehumidifier 14 and further dried. The dried sample gas is introduced into the gas analyzer 6 via a valve 15, a flow meter 16, and a filter 17 in this order. However,
The sample gas discharged from the gas analyzer 6 passes through the outlet conduit 18 to the inlet 19b furthest from the open end 19a of the atmosphere open tube 19, detailed in FIG.
is exhausted. The dry sample gas exhausted into the atmosphere opening pipe 19 is supplied as a dry purge gas to the first gas phase dehumidifier 4 via a purge gas intake pipe 21 equipped with a valve 20 on the pipe, and then to the second suction pump. 22.

On the other hand, the remaining part of the sample gas separated downstream of the first suction pump 13 is discharged to the outlet 19c of the atmosphere opening pipe 19 through a bypass pipe 24 provided with a valve 23.

Further, dry purge gas to the second gas phase dehumidifier 14 is supplied via a return path 26 equipped with a valve 25, and is supplied to the bypass pipe 2 through a bypass path 27.
It is discharged at 4.

In this embodiment, a semipermeable membrane type vapor phase dehumidifier 4,
14 is preferably a dehumidifier with the trade name PermaPure Dryer, and as is clear from FIG. It is composed of a large number of inner tubes 30, 30, 30 supported by each inner tube 30.
It is composed of NAFION, a product of E.I. DuPont, and has the function of transmitting water vapor. Therefore, when a sample gas containing water vapor is introduced into each inner tube 30 from the inlet 31 and discharged from the outlet 32, the water vapor in the sample gas passes through the wall of each inner tube 30 and flows into the outer tube 28. discharged inside. On the other hand, if the dry purge gas is allowed to flow from the inlet 33 to the outlet 34 of the outer tube 28, water vapor in the sample gas will be taken out by the dry purge gas.

According to the present invention configured in this manner, the sample gas discharged from the gas analyzer is exhausted into the atmosphere open pipe whose one end is open to the atmosphere, so that the pressure of the sample gas inside the analyzer is The pressure can be maintained at approximately atmospheric pressure regardless of increases or decreases in the suction capacity of the pump, and measurement errors due to pressure fluctuations can be eliminated. Furthermore, since the highly dry sample gas dehumidified through the first and second vapor phase dehumidifiers is passed through the first vapor phase dehumidifier as a dry purge gas, the dehumidification in the first vapor phase dehumidifier can be further enhanced. I can do it.

Next, another embodiment of the present invention will be described with reference to FIG. 5, in which the same parts as in FIG. 3 are denoted by the same reference numerals. A description of the same components as in FIG. 3 will be omitted, and different parts will be described. Sample gas discharged from the gas analyzer 6 is introduced into the second gas phase dehumidifier 14 through the purge gas intake pipe 35. On the other hand, the remaining portion of the sample gas separated downstream of the first pump 13 is exhausted through the pipe line 36 equipped with the valve 23 to the outlet 19b furthest from the open end of the air release pipe 19. The dry sample gas exhausted into the atmosphere opening pipe 19 is supplied as a dry purge gas to the first gas phase dehumidifier 4 through a purge gas intake pipe 21 equipped with a valve 20 on the pipe, and is then supplied to the first gas phase dehumidifier 4 as a dry purge gas. It is evacuated by pump 22.

Further, the dry purge gas introduced into the second gas phase dehumidifier 14 is exhausted through the exhaust pipe line 37 to the outlet 19c near the open end of the air release pipe 19.

According to another embodiment of the present invention configured in this manner, the outlet side of the gas analyzer 6 communicates with the atmosphere through the purge gas intake pipe 35, the second gas phase dehumidifier 14, and the exhaust pipe 37. Therefore, the pressure of the sample gas inside the gas analyzer can be maintained at approximately atmospheric pressure, and measurement errors of the gas analyzer can be reduced.

As described above, according to the present invention, the sample gas discharged from the gas analyzer is communicated with the atmosphere open pipe whose one end is open to the atmosphere.
The pressure of the sample gas within the gas analyzer can be maintained approximately constant without being affected by changes in the suction capacity of the suction pump, and measurement errors caused by the gas analyzer can be reduced.

In addition, since the dehumidified dry gas exhausted from one or two gas phase dehumidifiers was used as the dry purge gas supplied to the semipermeable membrane type gas phase dehumidifier, water vapor in the sample gas was effectively removed. This can reduce contamination of the reaction cell window of the gas analyzer and reduce drift.

In the above embodiment, an example was described in which two vapor phase dehumidifiers were used, but three or more may be used. In this case, the sample gas in the atmosphere open pipe is used as a dry purge gas at least in the first stage. Introduced into a vapor phase dehumidifier.

Furthermore, as mentioned above, it is clear that a single vapor phase dehumidifier may also be used.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing a conventional dehumidifier device for a gas analyzer, Fig. 2 is a system diagram showing a dehumidifier device for a gas analyzer according to the present invention, and Fig. 3 is a longitudinal sectional view showing a pipe open to the atmosphere. 4 is a vertical sectional view showing the structure of a gas phase dehumidifier, and FIG. 5 is a system diagram showing a dehumidifying device for a gas analyzer according to the present invention. 1...Gas extraction tube, 2...Gas sampling device, 4...
First gas phase dehumidifier, 6... Gas analyzer, 13... First suction pump, 14... Second gas phase dehumidifier, 19...
...Atmospheric release pipe, 21...Purge gas intake pipe, 22
...Second suction pump, 24...Bypass pipe line, 2
6...Return route.

Claims (1)

[Scope of Claims] 1. In a device in which a sample gas is introduced into a gas analyzer through a semi-permeable membrane type gas phase dehumidifier, a part of the gas discharged from the gas analyzer is used as a dry purge gas. 1. A dehumidifier for a gas analyzer, characterized in that the dehumidifier is introduced into a phase dehumidifier and is configured to discharge the remainder of the gas discharged from the gas analyzer into the atmosphere. 2. In the dehumidification device according to claim 1, the gas exhausted from the gas analyzer is exhausted into an atmosphere open pipe whose one end is open to the atmosphere, and a part of this exhausted gas is A dehumidifying device for a gas analyzer, characterized in that it is used as a purge gas. 3. The dehumidification device according to claim 1 or 2, wherein the vapor phase dehumidifier is provided in multiple stages, and the dry purge gas is introduced into the first stage of the vapor phase dehumidifier. A dehumidifying device for gas analyzers. 4. In the dehumidification device according to claim 1 or 2, the gas phase dehumidifier is provided in multiple stages, and the gas discharged from the gas analyzer is used as a dry purge gas in the final stage gas phase dehumidifier. A dehumidifier for a gas analyzer, characterized in that the dehumidifier is introduced into the atmosphere and then exhausted into the atmosphere open pipe.