JP3186602B2 - Gas analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas analyzer used for analyzing, for example, tail gas in a desulfurization plant.

[0002]

2. Description of the Related Art A gas analyzer of this type irradiates a specific light (ultraviolet light or infrared light) into a cell while flowing a gas to be measured through an analysis chamber (cell) for analysis. The amount of light absorption of the gas is measured from the amount of transmitted light, and the concentration of the gas is quantitatively analyzed from the result. An ultraviolet gas analyzer uses ultraviolet light, and an infrared gas analyzer uses infrared light.

[0003] The cell of such a gas analyzer is provided with a window for irradiating ultraviolet light or infrared light from the outside and a window for emitting light transmitted through the gas in the cell from the cell to the outside. ing. A cell window composed of a quartz rod or the like is provided in each of these windows. Needless to say, the installation of the cell window allows the gas to be measured to leak out of the cell by sealing the airtightly.

[0004]

The gas measured by the gas analyzer is tail gas or the like as described above.
It contains high temperature and considerable dust (dust), and when it touches the window of the cell, dew condensation due to the temperature drop and dust adheres to the cell window. The dew condensation and the adhesion of dust reduce light transmission (or the amount of transmission), which causes a decrease in measurement accuracy. In addition, the durability of the analyzer is reduced. In order to solve such a problem, attempts have been made to send air to the window to form an air curtain at the inner end of the cell window. However, since the supplied air is at room temperature, the temperature at the inner end of the cell window decreases, and dew condensation and dust adhesion occur, and the problem is not solved.

The present invention has been made in order to solve the above-mentioned problem, and provides a gas analyzer in which dew condensation and dust do not occur on the inner end of a cell window.

[0006]

In a gas analyzer provided by the present invention, a cell and a piping for introducing / discharging a gas to be measured into / from the cell are formed as a steam jacket having a double pipe structure in which steam flows inside. Swirling a gas conduit of air or an inert gas around the outer periphery of the measurement gas introduction / discharge pipe, and introducing a gas introduced from the gas conduit and heated by heat from a steam jacket into the cell;
It is configured to spray on the inner end of the window.

[0007]

FIG. 1 is an enlarged view of a main part of a gas analyzer provided by the present invention. FIG. 2 is a view showing the entire configuration of a gas analyzer according to the present invention. FIG. 1 is a diagram showing an entire system including a gas analyzer according to the present invention. The illustrated example shows the configuration of an ultraviolet gas analyzer.

In FIG. 3, the gas to be measured is introduced from the upper end opening of the pipe P1, and subsequently discharged from the left end of the pipe P6 via a pipe P2 with a ball valve for adjusting the flow rate. The circulation of this gas is performed by the steam ejector SE installed in the pipe P5 to which the pipe P6 is connected. As described above, in the case of tail gas in a desulfurization plant, the gas flow rate is about 400 l / min.
The analysis pipes P3 and P4 having a cell function are interposed between the pipes P2 and P5. In the case of this ultraviolet gas analyzer, a steam heater system is adopted as shown in the figure to prevent the temperature of the gas to be measured from dropping, and each of the pipes P1 to P6 has a double pipe structure. There is a steam jacket in the so-called steam jacket structure. This heating steam is supplied from the introduction pipe SP. CP is a connecting portion for connecting the inside of the outer pipe in each of the pipes P1 to P6. Also, S
E is a steam ejector for circulating gas.

[0009] Now, the analysis pipe P3 and P4 constitute the principal cell S1 and S2, performs the analysis of the measured gas, S1 is a cell for analyzing SO ₂ gas, S2 is H ₂
This is a cell for analyzing S + KSO ₂ gas. Therefore, the cells S1 and the light source unit K1 and SO ₂ light receiving portion J1 for gas for SO ₂ gas is opposed, the other cells S2 H ₂ S
+ KSO ₂ source unit K2 and H ₂ S + KSO ₂ receiving part J2 of the gas for the gas are opposed.

FIG. 2 shows only the SO2 gas analyzer portion shown in FIG. 3, but FIG. 2 shows a practical appearance in which a heat insulating material for insulating the analysis pipe P3 surrounds the entire surface and is bent. It is shown. In this ultraviolet gas analyzer, as shown in FIG. 3, ultraviolet light emitted from the light source unit K1 passes through the cell S1 in the axial direction, passes through the gas in the cell S1, and is received by the light receiving unit J1. The light receiving unit J1
The UV absorption of the gas is measured based on the output of the above, and the concentration of the gas to be measured is quantitatively analyzed. Since the ultraviolet rays pass through the gas in the cell S1, the cell S1 is provided with a light transmitting window (not shown) at both ends. Although this window is clearly shown in FIG. 3, reference numeral 8 denotes an injection port for blowing air or an inert gas onto the window to form an air curtain. The present invention has a feature in this air curtain forming mechanism, and a gas passage pipe HP for supplying gas to the injection port 8 is swirled around the outer periphery of the steam jacket of the analysis pipe P3. This swirling heats the supplied and injected gas.

The heated air or inert gas (hereinafter, nitrogen gas will be described as an example) is supplied to the window of the cell S1 and injected as shown in FIG. FIG. 1 is an enlarged cross-sectional view showing the right side of the cell 1, that is, the portion on the side where the ultraviolet light from the light source unit K1 is irradiated to the cell S1, and the irradiation window of the ultraviolet light for the cell S1 is a cell window 5. And is located at a fixed distance inward from the end of the cell S1. This is to prevent the temperature from dropping by positioning the window inside the steam jacket SJ. A cell window 5 for irradiating the inside with ultraviolet light is fitted to an inner end of the cell window 5. Numeral 1 denotes an outer tube and numeral 2 denotes an inner tube. The cell S1 has a double-tube structure with both tubes and a steam jacket SJ with a tube end 3. The cell window 5 is air-tightly installed at the end of the cell S1 in the fixed frame 6, and 9 is a sealing packing for that purpose. Cell window 5
Are sandwiched between the cover 4 and the fixing frame 6 and are integrally fixed to the end of the cell S1 with fixing screws. Further, between the cell window 5 and the fixed frame 6, a seal frame 7 holding a sealing material is screwed to the fixed frame 6, and the gas to be measured in the cell S1 is moved to the end of the cell S1 by such an airtight mechanism. Is prevented from leaking out. By the way, the injection port 8 is inserted in the cell S1 so that the inner end thereof coincides with the inner pipe 2, and is installed at a position where gas is blown to the inner end of the cell window 5.

Since the gas analyzer according to the present invention has the above configuration, the cell S1 is irradiated with ultraviolet light from the light source unit K1 for gas analysis, and at the same time, nitrogen gas is pressurized to perform gas analysis. It is guided to the injection port 8 by the pipe HP and is injected from the tip. At this time, the nitrogen gas is heated by the heat from the steam jacket SJ in the middle of the gas path pipe in which the gas path pipe HP is circling the steam jacket SJ. The curtain A serves as a heated air curtain and heats the inner end of the cell window 5 or maintains a temperature equal to the gas temperature of the inner end of the cell window 5. Therefore, no dew condensation occurs at the inner end of the cell window 5, and no dust or impurities adhere. Moreover, since the gas injection amount for forming the air curtain A is about 1 l / min, it is about 0.25% of the flow rate of the gas to be measured and can be ignored.

Although the features of the present invention have been described above, the present invention is not limited to the above and illustrated examples, but includes various modified embodiments utilizing the features of the present invention.
First, as described above, the present invention is applicable not only to an ultraviolet gas analyzer but also to an infrared gas analyzer, and is not limited to the ultraviolet gas analyzer in the illustrated example.
Of course, the mechanism of the cell window is not limited to the illustrated example. Furthermore, for the gas that forms the air curtain,
Helium gas may be used as an inert gas other than nitrogen gas, or air may be used as long as the gas to be measured does not have any trouble or influence. Further, even in the case of an ultraviolet gas analyzer, the present invention is not limited to the dual system as shown in FIG. Also, it goes without saying that the content of the gas to be measured is not limited to the above gas. The present invention includes all of these modified embodiments.

[0014]

The gas analyzer provided by the present invention is as described above. Therefore, when an air curtain is formed in the light transmitting portion at the inner end of the cell window, the formed air curtain is a heated air curtain. The window mechanism, that is, the inner end of the cell window is heated, or the inner end of the cell window maintains the same temperature as the gas temperature, and dew condensation of the measured gas occurs at the inner end of the cell window. No dust or impurities are attached. Therefore, the analysis function can be improved without lowering the durability of the gas analyzer.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a main part of a gas analyzer according to the present invention.

FIG. 2 is an external view showing a configuration of a gas analyzer according to the present invention.

FIG. 3 is a diagram showing an overall configuration of a gas analyzer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer tube 2 ... Inner tube 3 ... Tube end 4 ... Cover 5 ... Cell window 6 ... Fixed frame 7 ... Seal frame 8 ... Injection port 9 ... Packing A ... Air curtain SJ ... Steam jacket K1, K2 ... Light source J1, J2 ... Light receiving unit S1, S2 ... cells P1, P2, P5, P6 ... piping P3, P4 ... analysis piping

Claims (1)

(57) [Claims] 1. A cell having a cell window at both ends and a cell having a pipe for introducing / discharging a gas to be measured is irradiated with specific light from one of the cell windows, and flows through the inside of the cell based on the amount of light transmitted from the other cell window. In a spectrometer for measuring the amount of light absorption of a gas to be measured and quantitatively analyzing the concentration of the gas from the result, a steam having a double pipe structure in which steam flows through the cell and the gas introduction / discharge pipes to be measured. As a jacket, a gas conduit for air or an inert gas is swirled around the periphery of the gas introduction / exhaust pipe to be measured, and a gas introduced from the gas conduit and heated by heat from a steam jacket is introduced into the cell. A gas analyzer that blows the inner end of the window.