JP2002202288A - Laser ionization mass spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser ionization mass spectrometer capable of directly analyzing dioxins in exhaust gas. SOLUTION: This mass spectrometer is equipped with a sample introduction means 15 for introducing continuously exhaust gas 13 from a gas duct 12 into a vacuum chamber 11 as leakage molecular beams 14, a first laser irradiation means 18 for irradiating femto-second pulse laser beams 17 into the introduced leakage molecular beams 14 through a condensing lens 16, a second laser irradiation means 20 for irradiating the condensing position of the first laser beams 17 with nano-second pulse laser beams 19 with the same optical axis, and a time-of-flight mass spectrometer 23 equipped with an ion detector 22 for analyzing molecular ion 21 generated respectively by irradiation of the first laser beams 17 and the second laser beams 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various incinerators such as municipal waste incinerators, industrial waste incinerators, sludge incinerators, etc.
Laser ionization mass spectrometer for directly analyzing dioxins in exhaust gas discharged from pyrolysis furnaces, melting furnaces, etc. in real time with no time delay, and combustion control for controlling combustion in the furnace based on the analysis results of the analyzer About the system.

[0002]

BACKGROUND ART Dioxin has a high toxicity in a trace amount, and development of a highly sensitive analytical method is desired. Therefore, it is conceivable to apply a laser analysis method that enables high-sensitivity analysis.
In recent years, it has been proposed that by combining the supersonic jet method and the resonance-sensitized multiphoton ionization method, it is possible to measure the spectrum of a chlorine-substituted product which is a kind of dioxins (C. Weickhardt, R. Zimmermann, U.
Bosel, EWSchlag, Papid Commun, Mass Spectron, 7,198
(1993)).

[0003]

However, the above-mentioned proposal is a method for analyzing a gas in which the spectrum is simplified by jetting a gas sample into a vacuum and instantaneously cooling the gas sample to near absolute zero. The detection limit of dioxin and its derivatives (hereinafter referred to as “dioxins”) is about ppb, and the actual dioxin analysis requires 5 to 6 digits of concentration, which takes time and labor for detection. is there.

In the conventional manual analysis, it takes one to two months for the analysis result to be obtained. The daily generation of dioxins in the incinerator is measured, and the combustion control is performed as needed. It is difficult to drive to meet the appropriate regulation values.

[0005] On the other hand, it has been proposed that the total concentration of all organic chlorine compounds contained in the combustion exhaust gas is an effective indicator of the dioxin concentration.

[0006] The measurement of total organochlorine compounds is performed by adsorbing organic molecules on an absorbent once and then burning it to generate HCl.
This is done by measuring

However, there is a problem that HCl in the combustion exhaust gas is mixed and causes an error in measurement of the organic chlorine compound. In addition, the use of an adsorbent has a problem in that measurement requires 12 hours and cannot be applied to feedback control to a combustion furnace.

On the other hand, conventionally, it has been proposed to estimate the concentration of dioxins by measuring the CO concentration and control combustion in an incinerator or the like.
It has been confirmed that when the concentration is as high as 0 ppm, there is a correlation between the CO concentration and the dioxin concentration. However, as shown in FIG. 6, when the CO concentration is in a low concentration region of 50 ppm or less, there is no concentration correlation between the dioxin concentration and the CO concentration.
There is a problem that effective combustion control that prevents generation of dioxins cannot be performed. In particular, in recent years, as a result of the establishment of low CO concentration combustion control, it has been demanded to appropriately prevent the generation of dioxins by instantaneous measurement of dioxins directly measured.

Furthermore, when measuring dioxin precursors such as chlorobenzene (CB) and dichlorobenzene (DCB), which are conventionally considered to have a concentration correlation with dioxins, dioxins are not directly measured. Therefore, the in-incinerator state cannot be determined properly, and real-time analysis in exhaust gas is demanded, and it is desired to use the result for combustion control.

Further, when measuring the concentration correlated substance of dioxins, as described above, since a specific type of substance is measured in the selective ionization, the deviation of the optical axis of the laser beam and the sampling piping are not measured. When dioxins are actually detected due to other factors such as clogging but cannot be detected, there is a problem that the concentration of dioxins cannot be measured properly. In order to solve this problem, it is necessary to provide two measuring devices and perform the analysis while referring to them. However, there is a problem that the analyzing device becomes large.

[0011]

Means for Solving the Problems A first method for solving the above problems is described below.
The invention provides a sample introduction means for introducing a sample into a vacuum vessel, and irradiation for irradiating the introduced sample with a first laser beam having a wide spectrum width and a second laser beam having a narrow spectrum width with a time difference. Means, and a time-of-flight mass spectrometer for analyzing molecular ions generated by the laser irradiation.

According to a second aspect, in the first aspect, there is provided a difference spectrum detecting means for obtaining a difference spectrum after normalizing the spectrum by the first laser beam and the second spectrum by a specific ion signal. It is characterized by the following.

A third invention is characterized in that, in the first invention, the first laser light is a femtosecond laser, and the second laser light is a nanosecond or picosecond laser light.

A fourth invention is characterized in that, in the first invention, the wavelengths of the first laser and the second laser light are the same.

A fifth invention is characterized in that, in the first invention, the sample introduction means is a capillary column for continuously introducing the sample molecules so as to leak out.

In a sixth aspect based on the fifth aspect, the sample introduction means is a capillary column having a pore size of 2 μm.
It is characterized by being 50 to 530 μm.

In a seventh aspect based on the fifth aspect, the distance between the laser irradiation position of the leaked molecular beam introduced from the capillary column and the tip of the capillary column is 1 mm or less. .

An eighth invention is characterized in that, in the first invention, the sample is exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace or the like.

According to a ninth aspect, in the first aspect, the time-of-flight mass spectrometer is a reflectron mass spectrometer.

According to a tenth aspect of the present invention, there is provided a sampling means for directly collecting combustion gas containing dioxins in exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, etc. The apparatus is provided with any one of the first to ninth laser ionization mass spectrometers for analyzing, and is characterized in that total organic chlorine compounds in the combustion gas are measured.

According to an eleventh aspect of the present invention, a burned material is charged into a furnace such as an incinerator, a pyrolysis furnace, a melting furnace, etc., so that the amount of heat generated by the combustion is kept constant and the generation of harmful gases such as dioxins is suppressed. 10. A combustion control system for an incinerator, wherein the concentration of total organic chlorine compounds in exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace, etc., can be instantaneously measured.
Equipped with a laser ionization mass spectrometer and combustion air control means according to any one of the above, detects all organic chlorine compounds in the combustion gas without time delay, and according to the detected total organic chlorine compound concentration, the amount of combustion air And controlling emission of dioxins.

According to a twelfth aspect, in the eleventh aspect,
The combustion air control means controls the air amount and oxygen concentration of one or both of the primary combustion air and the secondary combustion air.

According to a thirteenth aspect, in the eleventh aspect,
The emission control of the dioxins is controlled by any one of a furnace temperature, a furnace gas convection time, a furnace stirring force, or a combination thereof.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

FIG. 1 is a schematic diagram of a laser ionization mass spectrometer according to the present embodiment. As shown in FIG. 1, the laser ionization mass spectrometer according to the present embodiment includes a sample introduction unit 1 that leaks exhaust gas 13 from a flue 12 into a vacuum chamber 11 and continuously introduces it as a molecular beam 14.
5, a first laser irradiating means 18 for irradiating the introduced leaked molecular beam 14 with a femtosecond pulsed laser beam 17 via a condensing lens 16, and the first laser beam 17
A second laser irradiating means 20 for irradiating a nanosecond pulse laser beam 19 on the same optical axis to the converging position of
7 and a time-of-flight mass spectrometer 23 having an ion detector 22 for analyzing molecular ions 21 generated by irradiation with the second laser beam 19.
In FIG. 1, 24 to 27 are electrodes, 28 is a mirror, 29
Denotes a digital oscilloscope, 30 denotes an arithmetic unit, and 31 denotes a laser introduction window.

In the present embodiment, a pulse delay circuit 32 is provided to control the irradiation of the laser light between the first laser irradiation means 18 and the second laser irradiation means with a time difference, and to trigger the laser light from the delay circuit 32. The trigger signal is used to detect the ion signal from the mass spectrometer.
In this way, mass spectra ionized by two types of lasers are obtained individually. Note that a laser Q power switch trigger signal may be used from a laser power supply.

Further, in the arithmetic unit 30, the first
Spectrum of the laser beam 17 and the second laser beam 19
Is normalized by a specific ion signal (for example, an ion signal of toluene having a mass number of 92), and then a difference spectrum is obtained to obtain a mass spectrum of only the organic chlorine compound.

FIG. 2 shows a time sequence of the laser beam. As shown in FIG. 2, FIG. 2A shows a waveform of a nanosecond signal, and FIG. 2B shows a waveform of a femtosecond signal. This deviation is controlled by a delay circuit, and measurement 35 and 36 are performed at each irradiation position, so that measurement using a femtosecond laser and measurement using a nanosecond laser can be performed. The time difference between the irradiation of the sample and the irradiation of the sample is, for example, in the case of using a laser of 100 Hz as a nanosecond and a laser of 1 kHz as a femtosecond, which is extremely short as 0.1 ms, so that the gas concentration does not fluctuate extremely. At the same time, a sample of the same concentration is irradiated with laser.

Also, a nanosecond pulse of the second laser beam 19
In the laser, the sensitivity of molecules containing chlorine due to the internal heavy atom effect
Is reduced and hardly detected, but the first laser light 1
7 femtosecond laser sensitivity of chlorine-containing organic compounds
Does not decline. Therefore, in a femtosecond laser
As shown in FIG. 3A, when all the organic compounds can be measured.
In both cases, in the case of the nanosecond laser, as shown in FIG.
Unsubstituted organic compounds will be measured. same
Irradiated using laser light of 266 nm as one wavelength
In the case, HCl, Cl _TwoIonization, etc. hardly occurs.
What is the spectrum of an organic compound by mass number even when ionized
It can be completely distinguished.

FIG. 3 is a simplified diagram of the detected spectrum, in which benzene and toluene are given as the non-chlorinated organic compounds, and chlorotoluene, dichlorotoluene and trichlorotoluene are shown as the chlorine-substituted organic compounds. .

Here, since the signal intensities of the two are often different due to the fact that the laser beam intensities are not completely the same, for example, the correction is performed to obtain a difference spectrum, as shown in FIG. 3 (C). A mass spectrum of only an organic chlorine compound can be obtained. At this time, the difference spectrum can be easily obtained by normalizing the signal intensity with the ion signal of toluene having a mass number of 92.

Further, by irradiating two kinds of laser beams having the same wavelength with the same optical axis, a factor that changes the pattern of the mass spectrum is eliminated, so that the organochlorine compound can be obtained quickly and accurately.

Here, when the sample introduction means 15 such as a capillary column is used, the temperature of the irradiated part of the laser is 100 K or more, so that the leaked molecular beam is ionized without cooling and the broadened molecular beam is cooled. A spectrum can be obtained.

The sample introducing means 15 may be any one which continuously supplies molecular beams. However, a capillary column is preferable in that it is made of quartz, so that organic molecules are hardly attached thereto.

The pore diameter is desirably 250 to 530 μm, preferably about 320 μm. This is because if the pore diameter of the capillary column is out of the above range, a good leaked molecular beam 14 will not be obtained. The material of the capillary column is preferably a non-dielectric material such as quartz.

The distance between the laser irradiation position of the leaked molecular beam 14 introduced from the capillary column 15 and the tip of the capillary column 15 is 1 mm or less, preferably 0.1 mm.
It is desirable to set it to about 3 mm. This is because it is preferable that the distance between the tip of the capillary column and the laser be closer to each other because the ionization efficiency of the laser is high, but if the distance is too close, dielectric breakdown may occur at the tip of the capillary column, and the width of the capillary may be extremely large. Gives a broad mass spectrum of In this case, the mass resolution is greatly reduced, and it is difficult to apply the method to the analysis of a real gas containing a large number of components. Therefore, it is preferable to be as close as possible at a distance that is not affected by the laser irradiation.

The laser pulse wavelength is 240 to 2
Preferably it is 70 nm. This is because the dioxins and the dioxin precursor can be ionized by setting the wavelength range.

The apparatus of the present invention can measure the total amount of all the organic compounds in the exhaust gas by using it for the measurement of the exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace, etc. Based on the concentration of dioxins having a relationship, it is suitable from the viewpoint of real-time analysis of dioxins.

Since the femtosecond laser measures all organic compounds, the measurement result of the total amount of all organic compounds in the exhaust gas can be involved in the correction of the concentration of dioxins. This means that organic compounds (eg, benzene, toluene, xylene, naphthalene, anthracene, and those in which various functional groups such as hydroxyl groups are bonded thereto) generated as a result of combustion of waste without using only organic chlorine compounds as an index. This is because measurement may be an effective index depending on the characteristics of the incinerator.

In the present invention, it is preferable to use a reflectron type mass spectrometer 19 from the viewpoint of improving mass resolution. This means that ions of the same mass, with higher (smaller) translational energies, fly longer (short) effectively by folding deeper (shallower) into the electric field upon folding. Therefore, ions having different energies can be converged on the detector at the same time.

In the present invention, the filter 41 interposed in the sampling tube 40 shown in FIG. 1 is preferably a ceramic filter that can withstand high temperatures.
In order to prevent clogging, it is preferable to use a filter having a dust removal rate of 99% or more.

In order to prevent the filter 41 of the sampling tube 40 from being clogged, a reverse cleaning means for performing reverse cleaning by, for example, purging with nitrogen gas or the like is provided. Since this clogging state uses a laser beam with a wide spectrum width and a plurality of organic molecules other than dioxins are simultaneously ionized, the organic molecules other than the dioxins (such as benzene) are used as indices, By monitoring the change in the signal intensity of the organic molecule, clogging can be monitored. Alternatively, regardless of the change in the signal intensity, the nitrogen gas may be purged every time a predetermined time elapses to perform the reverse cleaning.

Further, since the tip of the sampling pipe 40 is exposed to the high temperature of the combustion exhaust gas in the furnace or the flue, there is no risk of resynthesis of dioxins in this portion. Therefore, the distribution itself of the homolog of dioxins in the furnace or the flue can be directly collected.

A protective means 42 is provided around the collection tube 40.
, And the temperature is maintained so that the temperature of the collection tube is 120 to 200 ° C. If the temperature is lower than 120 ° C., the combustion gas 13 contains a large amount of moisture.
This is to prevent the aggregation, and to prevent the re-synthesis of the dioxins at a high temperature of 200 ° C. or more.

The exhaust gas suction speed is preferably about 0.5 to 1.0 liter / minute. This is to prevent submicron unit dust in the exhaust gas from adhering to the piping.

As the above laser, a semiconductor laser, an excimer laser, a third harmonic of a titanium sapphire laser, or the like can be used.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below.

A sample gas (benzene, toluene, chlorobenzene, dichlorobenzene, trichlorobenzene) was introduced into a vacuum chamber using a capillary column having an inner diameter of 320 μm and a length of 2 m. A laser for ionization irradiates the inside of the vacuum chamber with a femtosecond laser having a pulse wavelength of 266 nm and a nanosecond YAG laser having the same wavelength with the same optical axis. The generated ions were detected by a time-of-flight mass spectrometer.

As shown in FIG. 3, the measurement results show that all organic compounds (benzene, toluene,
Chlorotoluene, dichlorotoluene, and trichlorotoluene) were measured, and organic compounds (benzene, toluene) containing no chlorine were measured by the nanosecond laser. These intensities were corrected to obtain a difference spectrum (FIG. 3C).

As described above, all the organic compounds are measured without assigning the mass spectrum obtained by the felt-second pulse laser, and the organic compounds containing no chlorine are measured by the nano-second pulse laser. By measuring the total amount of all organic chlorine compounds from the spectrum, it became possible to obtain a signal correlated with the concentration of dioxins.

[Second Embodiment] Next, an embodiment of a method for controlling a furnace using the measuring apparatus of the present invention will be described. FIG. 4 is a schematic diagram of the combustion control system. As shown in FIG. 4, the control system according to the present embodiment includes an incinerator 51.
In a combustion control system in an incinerator, which keeps a constant amount of heat generated by combustion and suppresses generation of harmful gases such as dioxins, a combustion control system such as an incinerator, a pyrolysis furnace, a melting furnace, or the like is used. A measuring device 53 capable of instantaneously measuring all the organic chlorine compounds in the furnace 51 and a combustion air control means 54 are provided, and the dioxin concentration is determined by the correlation with the concentration of the total organic chlorine compound. This system changes the amount of combustion air according to the concentration. Here, the incinerator 51 in the present embodiment is a fluidized bed furnace, and has a configuration having a fluidized bed 55 at the bottom. On the downstream side of the fluidized bed 55, an ash chute 56 for transporting ash after burning the combustibles 52 to a predetermined position is arranged. A forced blower 59 is connected to the fluidized bed 55 via a pipe 58 having a primary combustion air amount control valve 57 interposed therebetween.

The primary combustion air is supplied from the lower part of the fluidized bed 55 to an arbitrary position. A forced blower 62 is connected to a lower portion of the fluidized-bed furnace 51 via a pipe 61 having a secondary combustion air amount control valve 60 interposed therebetween. Here, the secondary combustion air functions to burn the combustion gas generated in the primary combustion in the upper part of the fluidized bed furnace 51.

On the lower side wall of the fluidized-bed furnace 51, there is provided a combustion material supply hopper 63 for introducing combustion materials such as municipal solid waste into the fluidized bed 55. A feeder 64 is provided below the hopper 63 and driven by a motor to push out the combustion products 52 to the fluidized bed 55. This feeder 6
The combustion products 52 sent by the gas turbine 4 are gasified in the fluidized bed 55 and burned in the fluidized bed furnace 51 above the fluidized bed 55.

In the upper stage of the fluidized bed furnace 51, a fluidized bed furnace 5 is provided.
Boiler 65 for cooling the high-temperature combustion gas obtained by burning in 1, exhaust gas treatment facility 6 for removing toxic gas and particulate matter
6. An induction blower 67 for inducing exhaust gas and a chimney 68 for discharging exhaust gas to the atmosphere are sequentially connected. Also,
A spraying device 6 for spraying slaked lime, activated carbon and the like into the equipment 66 as needed near the upper part of the exhaust gas treatment equipment 66.
9 are arranged.

Above the fluidized-bed furnace 51, a measuring device 53 capable of instantaneously measuring all organic chlorine compounds in the combustion gas in the furnace is provided. The measuring device 53 has the configuration shown in FIG. 1, and the measurement information is electrically connected to the controller 71. The controller 71 is electrically connected to the primary combustion air amount control valve 57, the secondary combustion air amount control valve 60, the oxygen amount adjustment valve 73, and the auxiliary burner 72, respectively. Further, the controller 71 receives information 80 on the boiler evaporation amount and temperature measurement information 81, and sends signals to a control unit 82 for controlling the supply feeder, a control unit 83 for controlling the stoker, and an oxygen supply amount unit 84. Sending and controlling.

In the combustion control, the primary combustion air amount control or the secondary combustion air amount control, the oxygen concentration control of the combustion air, or all of them are required according to the concentration of dioxins obtained from the measured total organochlorine compounds. May be performed according to Further, the control may be performed by any one of the furnace temperature, the furnace gas convection time, the furnace stirring force, or a combination thereof.

When the controller 71 includes a predictive control means, it is possible to predict a change in the concentration of dioxins from time-series data based on the result of measurement by the dioxin analyzer 53. The prediction control means includes, for example, a fuzzy controller that controls a baseline (average value) and a chaos controller that suppresses generation of dioxin concentration.

Here, the chaos controller predicts the concentration of dioxins at a certain time ahead from the time-series data based on the measurement result by the dioxin analyzer 53, and when it predicts that a peak will occur, the secondary combustion air An operation amount that increases the amount is calculated. The fuzzy controller calculates the difference between the measurement result of exhaust gas and the set value of dioxin concentration,
An operation amount that makes it zero is calculated. The primary combustion air amount control valve 57 and the secondary air amount control valve 60 are operated based on the operation amount obtained by combining the operation amount obtained by the chaos controller and the operation amount by the fuzzy controller 29 to reduce the concentration of dioxins in the plant. Control.

An example of the combustion control operation using the chaos theory of the combustion control device having such a configuration is shown below, but the combustion control of the present invention is not limited to the following. First, combustion products 52 such as municipal waste are charged from a combustion product supply hopper 63 into a fluidized bed 55 of a fluidized bed furnace 51. The input combustion material is gasified in the fluidized bed 55 and burns in the fluidized bed furnace 51.
Then, the exhaust gas is cooled by a boiler 65, and harmful gases and particulate matter are removed by an exhaust gas treatment facility 66 such as a filtration type dust collector. The exhaust gas is induced by an induction blower 67 and discharged into the atmosphere from a chimney 68. On the other hand, in the upper part of the fluidized-bed furnace 51, the dioxin concentration is instantaneously measured by the dioxin analyzer 53, and a signal based on the measurement result is sent to a prediction control device (not shown). After performing the fluctuation prediction based on the chaos theory, a signal from the prediction control device is sent to the controller 71, and the opening degrees of the primary combustion air amount control valve 57 and the secondary fuel air amount control valve 60 are adjusted to adjust the primary combustion air amount. Adjust the secondary combustion air amount.

As described above, the dioxin analyzer 53 is attached to the upper part of the fluidized-bed furnace 51, the concentration of dioxins in the combustion gas in the furnace is measured in real time, and the prediction controller using the chaos theory is obtained from the time series data. And the primary combustion air amount and the secondary combustion air amount at the lower side of the fluidized-bed furnace 51 are adjusted based on the prediction, so that the peak of the dioxin concentration is reduced to a predetermined value or less. The amount of dioxins generated can be reduced.

By using the measuring device of the present invention, it is possible to estimate the concentration of dioxins in the furnace and the exhaust gas flue by 5 to 5.
Real-time detection becomes possible with a time delay of about 20 seconds. Therefore, as shown in FIG. 5, since the measurement is performed in such a manner that the signal B detected by the measuring device follows the peak A of the dioxins (DXN) in the furnace, the concentration of the dioxins is improved. Measurement can be performed, and by performing the above-described control immediately, the peak C in which the generation of dioxins is controlled is detected.

The place where the exhaust gas is collected is not limited to the inside of the furnace as described above, and may be arranged as required in the flue from the furnace to the boiler 65 and the flue from the boiler 65 to the flue gas treatment facility 66. Can be.

In particular, by installing the dioxin analyzer 53 between the boiler 65 and the exhaust gas treatment equipment 66, if no dioxins are generated in the furnace, the dioxin precursor is resynthesized downstream of the furnace. By this, it can be determined that dioxins have been generated, and by spraying activated carbon as an adsorbent from the spraying device 69, dioxins in exhaust gas can be adsorbed and discharge to the outside can be prevented.

Instead of spraying activated carbon, an auxiliary burner 72 as a sub-combustion means may be installed in the flue to burn off the generated dioxins.

[0065]

As described above, according to the first aspect, the sample introducing means for introducing the sample into the vacuum vessel, the first laser light having a wide spectral width and the spectral Since it is provided with irradiation means for irradiating the second laser light with a narrow width with a time difference and a time-of-flight mass spectrometer for analyzing molecular ions generated by the laser irradiation, the spectrum of the second laser light is provided. With a narrow pulse laser, the sensitivity of molecules containing chlorine is reduced due to the internal heavy atom effect, and it is hardly detected. However, with the first wide laser, all organic compounds containing chlorine can be measured without a decrease in sensitivity. From this result, a difference spectrum between the two can be obtained.

According to a second aspect, in the first aspect, there is provided a difference spectrum detecting means for obtaining a difference spectrum after normalizing the spectrum by the first laser beam and the second spectrum by a specific ion signal. Therefore, the conversion of the concentration of all the organic chlorine compounds becomes accurate.

According to a third aspect, in the first aspect, the first laser beam is a femtosecond laser and the second laser beam is a nanosecond or picosecond laser beam. In the nanosecond pulse laser, the sensitivity of molecules containing chlorine is reduced due to the internal heavy atom effect, and it is hardly detected,
The femtosecond laser of the first laser beam can measure all organic compounds including chlorine without lowering the sensitivity, and a difference spectrum between them can be obtained from the result.

According to a fourth aspect, in the first aspect, since the wavelengths of the first laser and the second laser light are the same, the concentration of the same sample can be measured under the same condition.

According to a fifth aspect, in the first aspect, the sample introduction means is a capillary column that continuously introduces the sample molecules so as to leak out, so that the molecules that have not been cooled by the leaked molecular beam are absorbed. The line width is improved, and the ionization efficiency is improved.

In a sixth aspect based on the fifth aspect, the sample introduction means is a capillary column having a pore size of 2 μm.
Since it is 50 to 530 μm, a leaked molecular beam is suitable.

According to a seventh aspect, in the fifth aspect, the distance between the laser irradiation position of the leaked molecular beam introduced from the capillary column and the tip of the capillary column is 1 mm or less. Efficiency is improved.

According to an eighth aspect, in the first aspect, since the sample is an exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace, or the like, the concentration of the organic chlorine compound in the exhaust gas can be analyzed in real time. Become.

According to a ninth aspect, in the first aspect, since the time-of-flight mass spectrometer is a reflectron mass spectrometer, detection sensitivity can be improved.

A tenth aspect of the present invention is directed to a sampling means for directly collecting combustion gas containing dioxins in exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, and the like, and a real-time sampling of the collected gas containing dioxins. The apparatus is provided with any one of the first to ninth laser ionization mass spectrometers for analyzing and measuring the total organic chlorine compounds in the combustion gas, so that the combustion state can be monitored.

According to an eleventh aspect of the present invention, a burned material is put into a furnace such as an incinerator, a pyrolysis furnace, a melting furnace, etc., so that the amount of heat generated by the combustion is kept constant and the generation of harmful gases such as dioxins is suppressed. 10. A combustion control system for an incinerator, wherein the concentration of total organic chlorine compounds in exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace, etc., can be instantaneously measured.
Equipped with a laser ionization mass spectrometer and combustion air control means according to any one of the above, detects all organic chlorine compounds in the combustion gas without time delay, and according to the detected total organic chlorine compound concentration, the amount of combustion air , And the emission control of dioxins is performed, so that good combustion can be performed.

According to a twelfth aspect, in the eleventh aspect,
Since the control means for the combustion air controls the air amount and the oxygen concentration of one or both of the primary combustion air and the secondary combustion air, it is possible to perform combustion in which the generation of dioxins is prevented.

According to a thirteenth aspect, in the eleventh aspect,
Since the emission control of the dioxins is controlled by the furnace temperature, the gas convection time in the furnace, or the stirring power in the furnace or a combination thereof, it is possible to perform combustion without generating dioxins according to the combustion state. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a laser ionization mass spectrometer according to the present embodiment.

FIG. 2 is a signal waveform diagram of a nanosecond laser and a femtosecond laser.

FIG. 3 is a diagram showing a measurement spectrum.

FIG. 4 is a schematic diagram of a combustion control system.

FIG. 5 is a diagram showing before and after combustion control.

FIG. 6 is a correlation diagram between CO and dioxins.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Vacuum chamber 12 Flue 13 Exhaust gas 14 Leakage molecular beam 15 Sample introduction means 16 Condensing lens 17 Femtosecond pulse laser light 18 First laser irradiation means 19 Nanosecond pulse laser light 20 Second laser irradiation means 21 Molecular ion REFERENCE SIGNS LIST 22 ion detector 23 time-of-flight mass spectrometer 24 to 27 electrode 28 mirror 29 digital oscilloscope 30 arithmetic unit and 31 laser introduction window 51 furnace 52 burned material 53 dioxin analyzer 54 combustion air control means 55 fluidized bed 56 ash chute 57 Primary combustion air amount control valve 58 Piping 59 Push-in blower 60 Secondary combustion air amount control valve 61 Pipe 62 Push-in blower 63 Combustion material supply hopper 64 Extruding feeder 65 Boiler 66 Exhaust gas treatment equipment 67 Induction blower 68 Chimney 69 Spray device 71 Control La 72 auxiliary burner

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 49/40 H01J 49/40

Claims (13)

[Claims] 1. A sample introducing means for introducing a sample into a vacuum vessel, and irradiating the introduced sample with a first laser beam having a wide spectrum width and a second laser beam having a narrow spectrum width with a time difference. A laser ionization mass spectrometer comprising: irradiation means; and a time-of-flight mass spectrometer for analyzing molecular ions generated by the laser irradiation. 2. The apparatus according to claim 1, further comprising a difference spectrum detecting means for obtaining a difference spectrum after normalizing the spectrum by the first laser beam and the spectrum by the second with a specific ion signal. Laser ionization mass spectrometer. 3. The laser ionization mass spectrometer according to claim 1, wherein the first laser light is a femtosecond laser, and the second laser light is a nanosecond or picosecond laser light. 4. The laser ionization mass spectrometer according to claim 1, wherein the first laser and the second laser light have the same wavelength. 5. The laser ionization mass spectrometer according to claim 1, wherein the sample introduction means is a capillary column that continuously introduces sample molecules so as to leak out. 6. The laser ionization mass spectrometer according to claim 5, wherein the sample introduction means is a capillary column, and has a pore diameter of 250 to 530 μm. 7. The laser ionization mass spectrometer according to claim 5, wherein the distance between the laser irradiation position of the leaked molecular beam introduced from the capillary column and the tip of the capillary column is 1 mm or less. . 8. The laser ionization mass spectrometer according to claim 1, wherein the sample is an exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace, or the like. 9. The laser ionization mass spectrometer according to claim 1, wherein the time-of-flight mass spectrometer is a reflectron type mass spectrometer. 10. A sampling means for directly collecting combustion gas containing dioxins in exhaust gas discharged from an incinerator, a pyrolysis furnace, a melting furnace, etc., and analyzing the collected gas containing dioxins in real time. A total organic compound detection apparatus, comprising: the laser ionization mass spectrometer according to any one of 1 to 9, wherein the total organic chlorine compound in the combustion gas is measured. 11. An incinerator in which incinerators, pyrolysis furnaces, melting furnaces, and the like are charged with combustion products to maintain a constant amount of heat generated by combustion and suppress generation of harmful gases such as dioxins. 10. The laser ionization mass spectrometer according to any one of claims 1 to 9, wherein a total concentration of organic chlorine compounds in exhaust gas from an incinerator, a pyrolysis furnace, a melting furnace, or the like can be instantaneously measured in the combustion control system. It is equipped with air control means, detects all organic chlorine compounds in the combustion gas without time delay, changes the amount of combustion air according to the detected total organic chlorine compound concentration, and controls the emission of dioxins. Combustion control system in an incinerator. 12. The combustion control in an incinerator according to claim 11, wherein the control means for the combustion air controls the air amount and oxygen concentration of one or both of the primary combustion air and the secondary combustion air. system. 13. The combustion in an incinerator according to claim 11, wherein the emission control of the dioxins is controlled by any one of a furnace temperature, a furnace gas convection time, a furnace stirring force, or a combination thereof. Control system.