JP2597180B2 - Aerial aldehyde capture device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerial aldehyde trapping device, and more particularly to an improvement in a mechanism for continuously trapping aldehyde in a gas in a liquid.

[Prior art] In recent years, environmental destruction due to an increase in the concentration of aldehydes in the atmosphere,
Particularly, the influence of formaldehyde is becoming a problem, and aldehyde analysis of automobile exhaust gas and the like is regarded as important.

Conventionally, with regard to measurement of aerial aldehyde, a method of monitoring by connecting a gas cell to an infrared spectrometer or a method of bubbling an aldehyde-containing gas, converting the aerial aldehyde into an aqueous solution, and measuring by a colorimetric method, etc. have been attempted. Had been.

[Problems to be Solved by the Invention] However, in the method of monitoring by connecting a gas cell to an infrared spectrometer, the sensitivity is low especially for continuous monitoring of a low concentration ppb level airborne aldehyde, and the operation is complicated. Had the problem of being

In the method of capturing in an aqueous solution by bubbling,
There is a problem in responsiveness to changes in the aldehyde concentration in the sample gas, and it is difficult to change various trapping conditions, so that continuous monitoring of air aldehyde has many problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to provide an aerial aldehyde capturing device capable of accurately capturing even a low concentration of aerial aldehyde and enabling continuous monitoring.

[Means for Solving the Problems] A gaseous aldehyde capturing device according to the present invention for achieving the above object, a gas sample conducting portion, a trapping solvent conducting portion,
And an aldehyde permeable membrane section.

The gas sample conducting section can conduct a gas sample containing gaseous aldehyde.

In addition, the trapping solvent conducting part conducts the trapping solvent capable of dissolving the aldehyde.

Further, the aldehyde permeable membrane portion is disposed between the two conducting portions, and is formed so as not to transmit the trapping solvent but to transmit the air aldehyde.

[Operation] Since the gas aldehyde trapping device according to the present invention is configured as described above, when the gas sample is conducted to the gas sample conducting portion, the gas aldehyde in the gas sample passes through the aldehyde permeable membrane portion. Then, it comes into contact with the trapping solvent in the trapping solvent passage.

And the trapping solvent dissolves and traps the gaseous aldehyde,
It is sent to a predetermined analyzer or the like.

Here, since the gaseous aldehyde is captured by the capture solvent, it is possible to adjust the aldehyde concentration in the capture solvent by appropriately changing the capture conditions such as the flow rate, pressure, and temperature of the gaseous sample. Low-concentration gaseous aldehydes can be accurately captured.

In addition, since the gas sample is not directly conducted into the trapping solvent as in the case of bubbling, extremely high responsiveness is obtained even when the aldehyde concentration in the gas sample changes without causing disturbance in the trapping solvent conduction. It becomes possible.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the aerial aldehyde trapping device according to the present invention.

In FIG. 1, the aerial aldehyde trapping device 10 includes a gas sample conducting part 12, a trapping solvent conducting part 14, an aldehyde permeable membrane part.
16 and including.

And the gas sample conducting part 12 is formed in a cylindrical shape,
A gas sample inlet 18 is provided at the right end, and a gas sample outlet 20 is provided at the left end.

On the other hand, the aldehyde permeable membrane section 16 is formed of a pipe made of a porous fluororesin membrane inserted into the gas sample conducting section 12, and the inside thereof is a trapping solvent conducting section through which the trapping solvent passes.
Make up 14.

The left end of the aldehyde permeable membrane 16 is connected to a pump 22 for supplying a trapping solvent (pure water in this embodiment), and the right end is connected to a reaction system such as an aldehyde analyzer.

Further, the gas sample introduction port 18 of the gas sample conducting section 12 is connected to, for example, an exhaust gas pipe 28 of an automobile via a switching cock 24 and a pump 26. The switching cock 24
The gas sample passage 30 and the nitrogen gas passage 32 are selectively switched to supply a desired gas to the gas sample inlet 18.

Further, the gas sample outlet 20 is connected to the gas outlet via a pressure valve 34.

The aerial aldehyde trapping device according to the present embodiment is configured as described above, and its operation will be described next.

First, the pump 22 is operated, and pure water is caused to flow through the trapping solvent conducting section 24 at a constant flow rate.

Then, the switching cock 24 is operated to connect the gas sample flow path 30 and the gas sample introduction port 18, and the pump 26 is operated.

Then, a gas sample (exhaust gas) is collected from the exhaust gas pipe 28 at a predetermined flow rate, and is introduced into the gas sample conducting unit 12 via the switching cock 24.

The gaseous aldehyde in the gaseous sample permeates through the aldehyde permeable membrane section 16 made of a porous fluororesin membrane, is trapped by the trapping solvent (pure water) flowing through the trapping solvent conducting section 14, and is sequentially sent to the reaction system. .

Here, by operating the pressure valve 34 to control the pressure in the gas sample conducting unit 12, the pressure at which the aldehyde in the gas sample passes through the membrane unit 16 can be changed to control the aldehyde capture rate. Can be.

It is also preferable to install the aerial aldehyde trapping device 10 in a constant temperature module as needed and heat it to a constant temperature.

That is, by heating the capturing device 10, the molecular motion of the sample component in the gas sample conducting portion 12 can be increased, and the transmittance of the aldehyde to the membrane portion 16 can be improved. It is also possible to reduce the adsorption of different components that are not permeated on the membrane or the like.

After the aldehyde trapping in the exhaust gas has been completed as described above, the switching cock 24 is then operated and the nitrogen gas flow path 32
Is connected to the gas sample introduction port 18, and nitrogen gas is introduced into the gas sample conducting section 12.

As a result, the exhaust gas in the gas sample conducting section 12 is sequentially discharged from the gas sample discharge port 20, and the trapped solvent in the base state where no aldehyde is present is sent to the reaction system.

Then, each part of the capturing device 10 can be cleaned, and the base can be set in the reaction system.

As described above, the aerial aldehyde trapping device according to the present embodiment
According to 10, the aldehyde in the exhaust gas can be efficiently captured by the capturing solvent. Also, the trapping solvent conducting section 14
Since the flow rate of the trapping solvent in the gas sample can be constantly adjusted to a constant value, the responsiveness to the fluctuation of the aldehyde concentration in the gas sample becomes extremely good.

Further, it is possible to adjust the temperature of the capture device 10, the flow rate of the capture solvent, the flow rate of the sample gas, and the sample gas pressure by an easy operation, and to set the optimum conditions according to the type of the gas sample or the measurement environment.

In the present embodiment, the example in which the pipe-shaped trapping solvent conducting part 14 is installed in the tubular gas sample conducting part 12 has been described. 12 can be installed.

Further, in the present embodiment, in order to increase the area of the aldehyde permeable membrane section 16 as much as possible and improve the aldehyde trapping efficiency, the aldehyde permeable membrane section 16 formed in a spiral or bellows shape in the gas sample conducting section 12. Installation is also suitable.

Further, connectors 16a and 16b are provided at the connection between the aldehyde permeable membrane 16 and the pump 22 and the reaction system, and the gas sample inlet 1 is provided.
The connector 18a is provided at the connection between the switching cock 8 and the switching cock 14, and the connector 20a is provided at the connection between the gas sample outlet 20 and the pressure valve 34 so as to be detachable.
It is itself replaceable.

Therefore, when clogging of the aldehyde permeable membrane 16 or contamination of other portions occurs, the entire capturing device 10 can be replaced.

FIG. 2 shows the gaseous aldehyde trapping device shown in FIG.
A continuous analyzer for aldehydes in exhaust gas using 10 is shown, and portions corresponding to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

In the illustrated example, the aldehyde trapping solvent sent from the trapping device 10 is supplied to the in-liquid aldehyde analyzer 54 via the flow path 50 and the solution injection injector 52.

Here, the liquid aldehyde analyzer 54 includes a pump 56 for supplying a nicotinamide adenine dinucleotide (NAD) solution, a pump 58 for supplying a phenazine mezosulfate solution, and a pump for supplying an isoluminol-microperoxidase mixed solution. 60 and immobilized enzyme reactor 62
And a chemiluminescence detector 64.

Then, the aldehyde trapping solvent sent through the channel 50 is first mixed with the NAD solution, and reaches the immobilized enzyme reactor 62.

The immobilized enzyme reactor 62 is formed by immobilizing formaldehyde dehydrogenase, and while formaldehyde in the aldehyde capture solvent is oxidized to formic acid,
NAD is reduced to NADH.

Then, the solution further containing NADH is mixed and reacted with phenazine mezosulfate sent from the pump 58 to generate hydrogen peroxide (H ₂ O ₂ ).

Next, it reacts with the mixed solution of isoluminol and microperoxidase sent from the pump 60.

As a result, the generated chemiluminescence is detected by the chemiluminescence detector 64.

Therefore, the chemiluminescence intensity detected by the chemiluminescence detector 64 is quantitatively proportional to the formaldehyde concentration in the aldehyde trapping solvent sent through the channel 50.

As described above, the aldehyde in the exhaust gas captured by the gaseous aldehyde capturing device 10 is specifically determined by the in-liquid aldehyde analyzer 54, particularly formaldehyde, and is compared with the amount of exhaust gas collected by the pump 26. Thus, the amount of formaldehyde in the exhaust gas can be accurately and continuously measured.

An aldehyde solution having a known concentration was injected from the solution injection injector 52, and the aldehyde concentration was compared with the chemiluminescence detector.
By comparing the amount of light emission according to 64, a calibration curve of aldehyde can be created.

Here, in preparing the calibration curve for aldehyde, it is necessary to switch the switching cock 24 to the nitrogen gas flow path 32 side so that the aldehyde does not flow into the trapping solution flowing through the flow path 50.

Furthermore, instead of connecting the nitrogen gas flow path 32 to the switching cock 24, an aldehyde standard gas with a known concentration is introduced,
It is also preferable to create a calibration curve that takes into account the capture efficiency of the aldehyde capture device 10.

As a result, it is possible to more accurately grasp the aldehyde concentration in the exhaust gas.

In addition, if aldehyde dehydrogenase is immobilized on the immobilized enzyme reactor 62, the total aldehyde amount can be measured.

Further, in the present embodiment, the mechanism for measuring chemiluminescence based on the presence of NADH is used as the aldehyde measuring device in liquid. However, for example, a mechanism for detecting NADH itself with a fluorescence detector is also possible.

Further, as shown in FIG. 3, cyclohexane-1,3-dione was supplied by a pump 70, mixed with an aldehyde trapping solvent, passed through a heated reaction coil 72, and mixed with aldehyde and cyclohexane-1,3-dione. It is also possible to provide a mechanism for measuring the reaction product of the above with the fluorescence detector 74.

As described above, the use of the aerial aldehyde capturing device according to the present embodiment makes it possible to efficiently and continuously capture aldehyde in a sample gas such as an exhaust gas of an automobile.

When used in combination with the liquid aldehyde analyzer shown in FIG. 2, the liquid aldehyde flowing through the flow path 50 is reacted with NAD with a predetermined immobilized enzyme, and the generated NADH is measured by a chemiluminescence method. Therefore, an extremely small amount of aldehyde can be accurately measured, and a desired measurement target such as formaldehyde or total aldehyde can be selected by changing the type of the immobilized enzyme constituting the immobilized enzyme reactor 62.

[Effects of the Invention] As described above, according to the aerial aldehyde trapping device according to the present invention, aldehyde in the gas sample is trapped by the trapping solvent through the aldehyde permeable membrane part.
A small amount of aldehyde can be efficiently and continuously captured stably.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration of an aerial aldehyde capturing device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a configuration of an aerial aldehyde analyzer using the aerial aldehyde capturing device shown in FIG. FIG. 3 is an explanatory view of another aldehyde analyzer. 10… Aerial aldehyde trapping device 12… Gas sample conducting part 14… Capturing solvent conducting part 16 …… Aldehyde permeable membrane part

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshiaki Tanaka 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-58-85135 (JP, A) JP-A-54-51584 (JP, A) JP-A-55-89751 (JP, A) JP-A-1-171351 (JP, U) JP-A-63-148853 (JP, U)

Claims (1)

(57) [Claims] 1. A gas sample conducting portion for passing a gas sample containing a gaseous aldehyde, a trapping solvent conducting portion for passing a trapping solvent capable of dissolving the aldehyde, and a trapping solvent conducting portion disposed between the two conducting portions. An aerial aldehyde capturing device, comprising: an aldehyde permeable membrane portion that is permeable to the aldehyde without being transmitted.