JP4923802B2 - Apparatus and method for measuring gas containing aromatic hydrocarbon - Google Patents

Description

  The present invention relates to a measuring device and a measuring method for a gas containing an aromatic hydrocarbon.

Sick house syndrome, which has become a problem in recent years, is caused by so-called VOCs (volatile organic compounds) such as toluene and xylene mixed in adhesives and inks applied to building materials. As a countermeasure against sick house syndrome, it is necessary to first measure the VOC in the air. Such a method is disclosed in Patent Document 1, for example.
JP 2005-83854 A

  However, after the building material is installed, it is difficult to prevent the generation of VOC from the applied ink. Therefore, as a fundamental solution, it is desirable to remove the VOC causing the ink from the ink before printing on the building material in advance. For that purpose, for example, it is necessary to detect VOC from the ink at the time of printing and to remove the ink having abnormality in advance. Therefore, since a VOC measuring device has already been commercialized, it is possible to measure VOC generated in a factory printing press or the like. By the way, since printing is performed continuously, the occurrence of VOC also changes over time. Therefore, it is necessary to measure VOC over time. However, the measurement apparatus as described above can only measure VOCs once, and cannot measure the occurrence of VOCs that change over time.

  The above-mentioned problems are not limited to VOCs, but also occur when measuring all other gases containing aromatic hydrocarbons. Aromatic hydrocarbons that change over time with a simple configuration There has been a demand for an apparatus capable of measuring the concentration of sucrose.

  The present invention has been made in order to solve the above problems, and has a simple configuration and is capable of continuously measuring the generation of a gas containing an aromatic hydrocarbon that changes over time. An object of the present invention is to provide a measuring device and a measuring method for gas containing gas.

The present invention has been made in order to solve the above-mentioned problem. When the gas containing the aromatic hydrocarbon is absorbed, the optical characteristics are changed, and the amount of change in the concentration of the absorbed aromatic hydrocarbon and the optical property are changed. A liquid reagent having a substantially constant relationship with a change amount of an optical parameter indicating a physical characteristic, a container for storing the reagent, a reagent extending into the reagent in the container, and the gas in the container A gas supply pipe to be supplied to, a measuring means for measuring the optical parameter, a control means for calculating the concentration of the aromatic hydrocarbon contained in the absorbed gas from the optical parameter measured by the measuring means , It has.

  According to this configuration, when the reagent used absorbs a gas containing aromatic hydrocarbons, the optical characteristics change, and the optical parameter indicating the amount of change in the concentration and the optical characteristics of the absorbed aromatic hydrocarbons. Since the ratio to the amount of change in the gas has a substantially constant relationship, as long as the ratio is constant, the gas can be continuously supplied to the reagent, and the concentration of the aromatic hydrocarbon over time changes Can be measured. That is, as the concentration of the aromatic hydrocarbon increases, the optical parameter indicating the optical characteristics of the reagent changes proportionally, so the concentration of the aromatic hydrocarbon contained in the reagent is derived from the measured optical parameter. be able to. At this time, if the gas is continuously supplied in a predetermined amount, the change with time of the concentration of the aromatic hydrocarbon contained in the absorbed gas can be measured. Moreover, the change with time of the concentration of the aromatic hydrocarbon can be easily measured without using an expensive apparatus. The optical characteristics referred to here include, for example, liquid reagent coloring, fluorescence generation, light reflection, refraction characteristics, etc. when aromatic hydrocarbons are absorbed, and the optical parameter is a color difference serving as an index. Fluorescence, absorbance, reflectance, refractive index and the like.

  In addition, the aromatic hydrocarbon made into object by this invention can be toluene, xylene, ethylbenzene, p-dichlorobenzene etc. which are aromatic hydrocarbons whose boiling point is 100-200 degreeC, for example. In addition, the reagent used in the present invention is particularly suitable if the ratio between the amount of change in the concentration of the absorbed aromatic hydrocarbon and the amount of change in the optical parameter indicating the optical characteristics has a substantially constant relationship. Although it is not limited, For example, what dissolved diiodine pentoxide in the acidic solution can be mentioned. Moreover, the liquid reagent as used in the field of this invention contains what melt | dissolved the reagent in aqueous solution or a solvent.

  In the above apparatus, it is preferable that the control means calculates the change amount of the optical parameter within a predetermined time, and notifies when the change amount exceeds a reference value. That is, when the gas supply amount is constant, if the change amount of the optical parameter within a predetermined time is larger than the reference value, the concentration of the aromatic hydrocarbon that changes over time is larger than the reference value within that time. It will be. At this time, since the control means notifies that, it is possible to easily recognize that the amount of the aromatic hydrocarbon exceeds the reference value.

  In the above reagent, the ratio between the concentration of the absorbed aromatic hydrocarbon and the optical parameter has a substantially constant relationship, but when the concentration of the aromatic hydrocarbon exceeds a predetermined amount, the relationship is constant. May disappear. If such a region having a certain relationship is calculated in advance, it can be known from the optical parameter that the concentration of the aromatic hydrocarbon absorbed by the reagent exceeds the region. By doing so, the concentration of the aromatic hydrocarbon can be accurately and continuously measured except for the time required for liquid exchange.

  The optical parameter is not particularly limited as long as the amount of change is an index that is proportional to the amount of change in aromatic hydrocarbon concentration. For example, when the reagent is irradiated with light of a predetermined wavelength. The measuring means can be an absorptiometer. There are various other methods, for example, reflectance, fluorescence, color difference, and refractive index are optical parameters, and as a measuring means for measuring each, a reflection photometer, a fluorimeter, a color difference meter, a CCD camera, a refractor A rate meter can be used.

Further, the method for measuring a gas containing an aromatic hydrocarbon according to the present invention has a change in optical characteristics when the gas containing an aromatic hydrocarbon is absorbed, and a change amount of the concentration of the absorbed aromatic hydrocarbon, a step for storing a reagent liquid ratio of the amount of change optical parameters indicating the optical characteristics has a substantially constant relationship to the housing body, the gas through the gas supply pipe extending reagent in said containing body A predetermined amount is supplied to the reagent, the optical characteristics of the reagent are changed, the optical parameters of the reagent with the changed optical characteristics are measured, and the supplied gas is determined from the measured optical parameters. and includes a step, a for calculating the concentration in the.

  According to this configuration, when the reagent used absorbs a gas containing an aromatic hydrocarbon, the optical characteristics change, and the optical property indicating the amount of change in the concentration of the absorbed aromatic hydrocarbon and the optical characteristics. Since the ratio to the amount of change in parameter has a substantially constant relationship, as long as the ratio is constant, even if gas is continuously supplied to the reagent, it is included in the gas from the measured optical parameters. The concentration of aromatic hydrocarbons can be derived. As a result, the change with time of the concentration of the aromatic hydrocarbon can be measured.

  Moreover, it is preferable to further provide a step of notifying when the amount of change of the optical parameter within a predetermined time exceeds the reference value. By doing so, it can be easily recognized that the concentration of the aromatic hydrocarbon exceeds the reference value.

  Further, it is preferable that the method further includes a step of replacing the reagent when the ratio between the concentration of the absorbed aromatic hydrocarbon and the optical parameter no longer shows a substantially constant relationship. Thus, by repeating the replacement of the reagent, the concentration of the aromatic hydrocarbon can be measured accurately and continuously.

  In the above method, the optical parameter can be, for example, absorbance when the reagent is irradiated with light of a predetermined wavelength.

  According to the present invention, it is possible to continuously and easily measure the generation of a gas containing an aromatic hydrocarbon that changes over time.

  Hereinafter, an embodiment of a gas measuring device containing an aromatic hydrocarbon according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an apparatus according to the present embodiment. In this embodiment, a case where the amount of toluene contained in the target air is continuously measured will be described.

  As shown in FIG. 1, the measuring apparatus according to this embodiment includes a cylindrical transparent container 1 that stores a liquid reagent M for detecting toluene. A gas supply pipe 11 for supplying a gas containing toluene and a gas discharge pipe 12 for discharging the gas are attached to the upper surface of the container 1. The gas supply pipe 11 extends into the reagent M to supply toluene to the reagent. A reagent supply pipe 13 for supplying the reagent M is provided on the upper surface of the container 1, and a reagent discharge pipe 14 for discharging the reagent M is provided on the lower surface.

  An illuminator 2 that irradiates light having a wavelength of about 400 nm is installed in the vicinity of the outer peripheral surface of the container 1 so that the reagent M is irradiated with light. In the vicinity of the outer peripheral surface of the container M opposite to the illuminator 2, an absorptiometer 3 is disposed in order to continuously measure the absorbance of the reagent irradiated with light. And this absorptiometer 3 is connected to the control part 4 comprised with a computer.

  Next, the reagent M used in this embodiment will be described. The reagent M used here is not particularly limited as long as it develops color when toluene is absorbed and there is a proportional relationship between the amount of change in the concentration of toluene and the degree of color development of the reagent. In fact, various reagents are known. As such a reagent, for example, a reagent in which diiodine pentoxide is dissolved in an acidic solution used in a detector tube based on JIS K0804 can be used, and absorbance is used as the degree of color development. That is, there is a proportional relationship between the amount of change in the concentration of toluene and the amount of change in the absorbance of the reagent.

  In this embodiment, this reagent is used. FIG. 2 shows the relationship between the toluene concentration and the absorbance when this reagent is absorbed with toluene and irradiated with light. Here, the absorbance when the reagent M is irradiated with light having a wavelength of about 400 nm as described above is used. When light is irradiated at this wavelength, the concentration of toluene can be quantified with high sensitivity. According to the graph of FIG. 2, from point A to point B, the concentration of toluene and the absorbance are in a substantially proportional relationship. That is, the absorbance increases proportionally as the concentration of toluene increases. On the other hand, the points higher than the origin 0 to the points A and B do not have a proportional relationship, and the absorbance does not increase so much even if the concentration of toluene increases. In the present embodiment, the concentration of toluene absorbed in the reagent from the absorbance is measured using the proportional relationship in the region from point A to point B. Hereinafter, the area of points A to B is referred to as an effective area.

  In the control unit 4 described above, the data of the graph is stored in a database, and the concentration of toluene is calculated over time from the measured amount of change in absorbance. When the toluene concentration within a predetermined time exceeds a reference value, the fact is displayed or a warning can be given by voice.

  Next, a method for measuring toluene by the above apparatus will be described with reference to FIGS. FIG. 3 is a flowchart of the measurement method, and FIG. 4 is a graph showing an example of the relationship between absorbance and time. In this embodiment, since the effective area of the reagent is used, it is necessary to first adjust the reagent M so that it is in the effective area. Therefore, toluene is added to the reagent until the reagent M reaches the point A in the graph (S1).

  Subsequently, a gas to be measured is supplied from the gas supply pipe 11 by a certain amount (S2). The supply amount of gas per time at this time is also input to the control unit 4 in advance. Thus, when the gas is supplied, the absorbance is measured, and the amount of change in absorbance per unit time is measured (S3), the control unit 4 calculates the concentration of toluene based on the amount of change in absorbance. (S4). Here, as an example, a case where the absorbance as shown in FIG. 4 is measured will be described. First, when supply of gas is started, toluene is already added to the reagent M, so the initial value of absorbance is L1. Thereafter, until time T1, since the supplied gas does not contain toluene, the absorbance does not increase and remains constant. Then, the absorbance increases from the time T1. Between these times T1 and T2, the absorbance increases at the inclination angle α. At this time, the control unit 4 calculates the rate of increase in absorbance per unit time, and calculates the amount of increase in toluene concentration per unit time based on the amount of gas supplied per unit time and the graph of FIG. (S4). If the toluene concentration calculated at this time exceeds the reference value X (YES in S5), the control unit 4 notifies that (S6). 4 shows that the reference value X was exceeded when the rate of increase in absorbance reached the inclination angle β at times T3 to T4, which is shown in FIG. 5 described later. The notification method may be either display or sound warning.

  According to FIG. 4, since the absorbance does not change at times 0 to T1, T2 to T3, and T4 to T5, toluene is not contained in the supplied gas. On the other hand, since the graph is inclined at times T1 to T2, T3 to T4, and T5 to T6, it can be seen that toluene is contained in the gas. When the graph is inclined, the concentration of toluene is calculated in the control unit 4 as described above. Therefore, in the case of the gas shown in the graph of FIG. 4, the relationship between time and the concentration of toluene is, for example, as shown in FIG.

  Thus, the measurement of the toluene concentration is continued, and as shown in FIG. 4, when the absorbance becomes L2 at time T6 (NO in S7), the reagent used here exceeds the effective area shown in FIG. Therefore, the measurement is stopped and the reagent is exchanged (S8). This is because if the effective region is exceeded, the absorbance and the toluene concentration do not show a proportional relationship, so that an accurate toluene concentration cannot be calculated from the absorbance. Accordingly, the reagent is discharged from the reagent discharge tube 14 of the container 1 and a new reagent is supplied from the reagent supply tube 13 into the container 1.

  As described above, according to the present embodiment, the reagent M to be used is colored when it absorbs toluene, and the ratio between the amount of change in the absorbed toluene concentration and the amount of change in absorbance has a substantially constant relationship. Therefore, as long as the ratio is constant, the gas can be continuously supplied to the reagent, and the change in the concentration of toluene over time can be measured. That is, since the absorbance changes proportionally as the concentration of toluene increases, the concentration of toluene contained in the reagent can be derived from the measured absorbance. At this time, if the gas is continuously supplied by a predetermined amount, the change with time of the concentration of toluene contained in the absorbed gas can be measured. Further, it is possible to easily measure a change with time in the concentration of toluene without using an expensive apparatus.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, A various change is possible unless it deviates from the meaning. For example, the measuring device can be applied to a printing press, and can measure VOCs such as toluene generated during printing over time. An example is shown in FIG. This figure shows an example in which the above-described measuring apparatus is installed in a factory equipped with three gravure printing presses P1 to P3. Each printing press P1 to P3 is provided with four printing units U1 to U4, and these printing units U1 to U4 are provided with branch lines A1 to A4 for exhausting air. Further, the branch lines A1 to A4 are connected to an exhaust line B, and the exhaust that passes through the exhaust line B is processed as factory exhaust. And measuring device S1-S4 mentioned above is attached to each printing unit U1-U4. However, a control unit is not attached to each measurement device S1 to S4 provided here, and a control unit 4 is provided separately from each measurement device S1 to S4. That is, each measuring device S <b> 1 to S <b> 4 is connected to one control unit 4 via the signal line E. And the light absorbency measured by each measuring device S1-S4 is transmitted to the control part 4, and the toluene concentration which generate | occur | produces in each printing unit U1-U4 intensively in the control part 4 is calculated.

  According to the above configuration, in a multicolor printing press having a plurality of printing units such as a gravure printing press, toluene generated in each of the printing units U1 to U4 can be measured over time, and a reference value can be set. Since it will alert | report from the control part 4 when exceeding, it can recognize easily. In addition, since the measuring device is provided in each of the printing units U1 to U4, it can be easily recognized which toluene has exceeded the reference value in which printing unit. Thereafter, the source of toluene can be removed by ink exchange or the like.

  Moreover, in the said embodiment, although the cylindrical thing is used as a container which accommodates a reagent, it is not limited to this, Various things, such as a cube, a rectangular parallelepiped, and an Erlenmeyer flask type, can be used.

  By the way, in the said embodiment, although the density | concentration of toluene is measured, it is not limited to this, Measurement object is a gas containing aromatic hydrocarbons, especially xylene and ethylbenzene whose boiling point is 100-200 degreeC. It is effective for p-dichlorobenzene and the like, and can also be applied to aromatic hydrocarbons belonging to VOC whose boiling point is defined at 50 to 260 ° C. Further, the reagent is not particularly limited as long as the ratio of the change in the concentration of toluene and the change in the absorbance of the reagent has a substantially constant relationship, but other than those shown in the above-described embodiments. Various types as will be described later can be used. Furthermore, optical parameters other than absorbance can be used, and various things such as reflectance, color difference, refractive index, etc. can be used in addition to fluorescence as described later. Examples are given below.

 (1) A reagent having a proportional relationship between the absorbance of a dye produced by reaction with an aromatic hydrocarbon such as toluene and the concentration of the reacted toluene can be used. For example, when p-dimethylaminobenzaldehyde as described in JP-A-2005-83854 is used, the concentration of toluene or the like is measured by measuring the absorbance of the dye produced by the reaction with toluene or xylene. Can do. More specifically, the dye produced has an absorption peak near the wavelength of 455 nm, but p-dimethylaminobenzaldehyde hardly absorbs light at this wavelength, so that the dye of the product can be easily measured. Thus, the concentration of toluene or the like can be measured. Incidentally, p-dimethylaminobenzaldehyde can be produced by the method described in the above publication.

 (2) A reagent having a proportional relationship between the fluorescence of a product produced by reacting with an aromatic hydrocarbon such as toluene and the concentration of the reacted toluene can be used. For example, when 9,10-bis- (diphenyl-phosphinothionyl) -anthracene as described in JP-A-2005-187382 is used, the fluorescence of the product produced by the reaction with toluene or benzene is measured. Thus, the concentration of toluene or the like can be measured. More specifically, after bringing toluene or the like into contact with the reagent, a fluorescent lamp is irradiated, and fluorescence is measured with a fluorometer. In the above reagent, the excitation wavelength at the time of fluorescence measurement is preferably 420 nm, for example, and the measurement wavelength is preferably 470 nm. By this method, only the fluorescence of toluene and benzene can be selectively measured. 9,10-bis- (diphenyl-phosphinothionyl) -anthracene can be produced by the method described in the above publication.

It is a schematic block diagram which shows one Embodiment of the measuring apparatus of the gas containing the aromatic hydrocarbon which concerns on this invention. It is a graph which shows the relationship between the density | concentration of toluene, and a light absorbency. It is a flowchart which shows the measuring method of toluene in the apparatus shown in FIG. It is a graph which shows a time-dependent change of a light absorbency. It is a graph which shows the time-dependent change of the density | concentration of toluene. It is a schematic block diagram of the printing machine to which the measuring apparatus of this invention is applied.

Explanation of symbols

1 container 11 gas supply pipe 3 absorptiometer (measuring means)
4 Control unit (control means)
M reagent

Claims (8)

When the gas containing the aromatic hydrocarbon is absorbed, the optical characteristics change, and the ratio between the change in the concentration of the absorbed aromatic hydrocarbon and the change in the optical parameter indicating the optical characteristics is substantially constant. A liquid reagent having a relationship;
A container for storing the reagent;
A gas supply pipe extending into the reagent in the container and supplying the gas to the reagent in the container;
Measuring means for measuring an optical parameter of the reagent whose optical properties have changed;
Control means for calculating the concentration of aromatic hydrocarbons contained in the absorbed gas from the optical parameters measured by the measuring means ;
An apparatus for measuring a gas containing an aromatic hydrocarbon.   The apparatus for measuring a gas containing an aromatic hydrocarbon according to claim 1, wherein the control means performs notification when the amount of change in the optical parameter within a predetermined time exceeds a reference value.   3. The apparatus for measuring a gas containing an aromatic hydrocarbon according to claim 1, wherein the control means stops the supply of the gas when the ratio no longer shows a substantially constant relationship.   The aromatic hydrocarbon according to any one of claims 1 to 3, wherein the optical parameter is an absorbance of the reagent when the reagent is irradiated with light having a predetermined wavelength, and the measuring unit is an absorptiometer. Gas measuring device including. When the gas containing the aromatic hydrocarbon is absorbed, the optical characteristics change, and the ratio between the change in the concentration of the absorbed aromatic hydrocarbon and the change in the optical parameter indicating the optical characteristics is substantially constant. Storing a liquid reagent having a relationship in the container ;
Supplying the gas to the reagent by a predetermined amount via a gas supply pipe extending into the reagent in the container, and changing the optical characteristics of the reagent;
Measuring the optical parameters of the reagent with altered optical properties;
Calculating the concentration of aromatic hydrocarbons contained in the supplied gas from the measured optical parameters ;
A method for measuring a gas containing an aromatic hydrocarbon, comprising:   The method for measuring a gas containing an aromatic hydrocarbon according to claim 5, further comprising a step of performing a notification when a change amount of the optical parameter within a predetermined time exceeds a reference value.   7. The method according to claim 5, further comprising replacing the reagent when the ratio between the concentration of the absorbed aromatic hydrocarbon and the optical parameter no longer shows a substantially constant relationship. A method for measuring a gas containing an aromatic hydrocarbon.   The method for measuring a gas containing an aromatic hydrocarbon according to any one of claims 5 to 7, wherein the optical parameter is absorbance of the reagent when the reagent is irradiated with light having a predetermined wavelength.

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