JPS6270729A - Apparatus for sampling flue gas specimen in chimney - Google Patents

Abstract

PURPOSE:To enable highly accurate measurement and to extend the replacement cycle of a filter element and a gas heater, by mounting a jacket pipe to a gas suction pipe over the total length thereof and providing a mist filter to a pretreating pipe. CONSTITUTION:A gas sampler 2 is provided in the vinity of the upper end of a chimney 1 equipped with a washing and desulfurizing apparatus of a flue gas and a jacket pipe 4 is mounted to the gas suction conduit 3 connected to said gas sampler 2 and extending to the vicinity of the ground along the total length of said conduit 3. A steam pipe 6 is connected to the jacket pipe 4 and the outer surface of the jacket pipe 4 is covered with a heat insulating material 11. A mist filter 18 is provided to the pretreating pipe 15 connecting the inlet of the gas heater positioned on the ground and the gas suction conduit 3 and a gas analyser is connected to the outlet of the gas heater 23 through a feed pipe 25 and a pump 26. By this method, the flue gas specimen can be sent to a gas analyser in a saturated state.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a device for collecting exhaust gas samples in a chimney. What is the concentration of residual components such as sulfur oxides (SOx)? ll! ! It is used to determine the

(Prior Art) In order to lower the concentration of sulfur oxides in the exhaust gas released into the atmosphere, it is known to wash the exhaust gas in a chimney with water. In order to test the concentration of sulfur oxides in the exhaust gas after water washing that is released into the atmosphere, a gas sampling device is installed inside near the top of the chimney, and this gas sampling device and a gas analyzer on the ground are connected to a long gas suction device. They were connected via a conduit, and a suction pump installed in the gas suction conduit collected exhaust gas samples and sent them to the gas analyzer. However, since the above exhaust gas sample has just been washed with water and has a humidity of 100%, the water vapor in the exhaust gas sample may be exposed due to the temperature drop during transfer, producing sulfuric acid or sulfur oxides. In order to prevent this, conventional methods have been to heat the exhaust gas sample by attaching a gas heater to the gas sampler or wrapping a heating wire around the gas suction conduit described in -1-. was.

In addition, a gas heater is provided as a pretreatment device n on the inlet side of the gas analyzer in the ground to reheat the exhaust gas sample, and the gas suction conduit is branched at the outlet of this gas heater.

It is also known to connect one end to a gas analyzer and open the other end to the atmosphere via a mist filter, a flowator and an air aspirator.

(Problem to be solved by the invention) If a gas heater is attached to the gas sampler and the exhaust gas sample is heated above the saturation temperature, it is possible to slightly delay the time it takes for pain to subside compared to when no heating is done. However, since the gas heater was installed near the top of the chimney, if the chimney was high, the distance to the gas analyzer would be long, making it almost ineffective. In addition, when a heating wire is wrapped around a gas suction conduit, the contact area with the heated object varies, making it difficult to maintain a constant temperature over the entire length, resulting in abnormal heating in one area or breakage of the heating wire. Therefore, if the gas suction conduit becomes long, it becomes difficult to maintain the wandering gas sample above the saturation temperature, and the moisture in the exhaust gas sample becomes a drain. In addition, if a gas heater is installed on the artificial side of the gas analyzer to reheat the exhaust gas sample, it only prevents exposure from this position to the gas analyzer; It was almost impossible to vaporize the exposed material again. Therefore, even if these are used together, the height of the chimney will be 25
m or more, the exhaust gas sample collected near the top of the chimney cannot be transferred to the gas analyzer in a saturated state without being exposed, and therefore a? There was a problem that the I-determination accuracy decreased and the verification tolerance could not be satisfied.

On the other hand, since the mist filter was installed at the rear of the gas heater, the molds in the exhaust gas sample were baked onto the inner wall of the gas heater at high temperatures, reducing the heating performance of the gas heater itself. The heater had to be replaced approximately every three days. Furthermore, in conventional mist filters, the filter element is made by molding a thin web of glass fiber, cellulose fiber, etc. into a cylindrical shape using phenol resin or the like.

It was easily clogged and became unusable after just one day of operation.

This invention allows exhaust gas samples to be sent to the gas analyzer on the ground in a saturated state without exposing them even when the height of the chimney exceeds 25 m, making it possible to perform highly accurate measurements that meet certification tolerances. This system facilitates the continuous automatic analysis of oxides by removing dust particles from exhaust gas samples, and also greatly extends the replacement cycle of the filter element of the mist filter and the gas heater.

(Means for solving the problem) A gas sampling device is installed near the top of the chimney equipped with a flushing desulfurization device for flue gas, and a jacket is installed along the entire length of the gas suction pipe that is connected to this gas sampling device and extends to near the ground. A heating medium conduction pipe is connected to this jacket pipe, and the outer surface of the jacket pipe is further covered with a heat insulating material, and the above-mentioned gas suction pipe is connected to the gas heater inlet located above ground. A mist filter is interposed in the pretreatment pipe connecting the gas heater, and a gas analyzer is connected to the outlet of the gas heater via a feed pipe and a pump.

(Operation) A part of the flue gas that has been washed and desulfurized in the chimney is collected as a flue gas sample by a gas sampler near the top of the chimney, and is transported to the ground through the gas suction pipe. At this time, the above-mentioned exhaust gas sample is heated by the steam supplied to the jacket pipe outside the gas suction conduit and the heat medium vapor such as dowsum, so after being collected by the gas sampling device, the temperature is almost constant. It is transported to the ground in its saturated state at the time of collection without descending. Therefore, the temperature of the heating medium in the jacket pipe is preferably 150 to 160°C; if it is less than 150"C, the wandering gas sample will turn into a drain, and if it exceeds 160"C, the gas suction pipe will expand excessively, shortening its life. In other words, the temperature of the heat medium such as the supplied steam is reduced so that the temperature inside the jacket pipe is maintained within the above range.

The IJ1 gas sample, which was transported to the ground by the gas suction pipe, is sent to the filter through the pretreatment pipe to Mis1, where dust and dirt are removed, and then sent to the gas heater to be reheated. It is then sent to the gas analyzer from the outlet of the gas heater via a feed pipe and a pump. At this time, the gas sample is sent to the gas heater after passing through the mist filter, so the amount of dust etc. in the exhaust gas sample that burns onto the inner wall of the gas heater is extremely small, and the gas heater itself There is almost no decline in the heating performance of
The replacement cycle is significantly extended. Furthermore, the gas suction pipe is not corroded by sulfur oxides, etc.
Any material may be used as long as it can withstand exhaust gas temperature, but it is particularly preferable to use a material made of fluororesin or one whose inner surface is coated with fluororesin.

Additionally, multiple steam pipes and drain pipes as heat medium conduction pipes can be connected to the jacket pipe at predetermined intervals. In this case, steam supplied from each steam pipe passes through the jacket pipe. As it descends, it exchanges heat with the exhaust gas sample, and when its temperature drops, it is immediately discharged from the drain pipe and replaced with fresh steam supplied from the steam pipe, which reduces the temperature drop of the exhaust gas sample. In addition, the filter element of the mist filter is preferably made of a nonwoven fabric with a porosity of 10 to 40% and made of synthetic fiber filaments of 0.5 to 5 deniers. However, because a water film is not formed,
Clogging is further reduced.

(Example) In FIG. 1, a chimney 1 has a height of about 50 m, and is equipped with a water washing desulfurization device (not shown) below.

A gas sampling device 2 is attached to the inner side near the upper end of the chimney 1, and a gas suction conduit 3 made of fluororesin is connected to the outer protrusion of the gas sampling device 2 and extends downward. As shown in FIG. 2, this gas suction conduit 3 is inserted into a jacket pipe 4, and a plurality of steam pipes branch from the main pipe 5 for supplying steam at the upper end and lower end of this jacket pipe 4. (Heating medium conducting pipes) 6 are connected at intervals of about 10 m, and a cock 7 is provided for each steam vibro. A plurality of drain drain pipes 8 corresponding to these steam vibros are connected to the gas suction conduit 3 at a position below the connection part of the corresponding steam vibro, and the other end of each drain drain pipe 8 is It is connected to a drain drain main pipe 10 via a steam trap 9. Then, the outer surface of the jacket pipe 4 is covered with a heat insulating material 11.

A drain trap 14 is connected to the jacket pipe 4 via a drain separator 12 and a cock 13 near the end of the extraction line consisting of the gas suction conduit 3, jacket pipe 4, and heat insulating material 11. On the other hand, at the end of the extraction line, one end of each of a pretreatment pipe 15 and a bypass pipe 16 are connected to the gas suction conduit 3, and a cock 17a, a mist filter 18, and a cock 17b are connected to the pretreatment pipe 15. The other end of the bypass pipe 16 is connected to the outlet side of the cock 17b, and the bypass pipe [6
A cock 19 is provided. As shown in FIG. 3, the above-mentioned Miss 1 filter 18 is a cylindrical filter in which a nonwoven fabric layer 18b with a porosity of 25% and made of 3-denier synthetic fiber filaments 1 is laminated on the outer surface of a porous pipe 18a. The filter element 18c is equipped with an element 18c so that the exhaust gas sample passes through the filter element 18c from the outside to the inside, and drain bottles 1 to 21 are installed on the bottom of the case via a safety protection box 20 for preventing suction from the drain. installed,
Drain in the exhaust gas sample is collected in a drain pot 21.

A cock 22, a gas heater 23, and a cock 24 are further interposed in this order in the pretreatment pipe 15, and a feed pipe 25 having a heat insulating layer and a pump 2 are connected to the cock 24.
A gas analyzer (not shown) is connected via the gas pipe 27 to the jacket 23a of the gas-heated pipe 23.
and steam 1-wrap 28 are installed, respectively. Note that a cock 29 is interposed in the steam pipe 27.

Thus, a flushing pipe 32 and a water purification pipe 33 are connected in parallel to the upstream side of the inlet cock 22 of the gas heater 23 via a cleaning pipe 31 having a cock 30, and these flushing pipes 32 and Pressure gauges 32a, 33a and cocks 32b, 3; 3b are installed in the water purification pipe 33, respectively.

Further, an exhaust pipe 34 is connected to the outlet side of the gas heater 23, a flowator 35 and an air aspirator 3G are sequentially attached to this air pipe 34, an air pipe 37 is connected to this air aspirator 36, and an air pipe 37 is connected to this air pipe 34. 37, pressure gauge 38, air set 39, cock 40
are interposed in turn.

In the above structure, when the steam vibro cock 7 along the gas suction conduit 3 is opened, steam is supplied into the jacket pipe 4 outside the gas suction conduit 3, and drain is discharged from the drain pipe 8.10 and the drain separator] The HP gas sample discharged through 2 and collected from the chimney 1 descends within the gas suction conduit 3 while being maintained at a predetermined temperature. The cock 19 of the bypass pipe 16 is closed, and the cocks 17a, 17b, 22.24 of the pretreatment pipe 15 are opened.
Further, when the cock 30 of the cleaning pipe 31 is closed, the exhaust gas sample is sent to the gas analyzer through the mist filter 18 and the gas heater 23. However, gas heater 2
When the cock 24 on the outlet side of the air aspirator 3 is closed and the cock 40 of the air pipe 37 is opened to send compressed air, the air aspirator 3
6, the above exhaust gas sample is transferred to the exhaust pipe 34.
flow to the flow rater 35 and air aspirator 36.
released into the atmosphere via. In addition, pretreatment pipe 1
Close the cocks 17a, 17b, 22 of No.5, and close the cocks 19.5 of bypass pipe 16. Cock 30 of cleaning pipe 31
And when the cock 32b of the flushing pipe 32 is opened and nitrogen gas is supplied to the flushing pipe 32,
Nitrogen gas flows backward through the gas suction conduit 3 to clean the inside, and when the cock 33b of the water purification pipe 33 is opened instead of the cock 32b of the flushing pipe 32 to supply cleaning water, the inside of the gas suction conduit 3 is is washed with wash water.

(Effects of the Invention) This invention covers the gas suction conduit for guiding the exhaust gas sample collected near the top of the chimney to the ground with a jacket pipe, and sends a heat filter inside the jacket pipe. Since the entire length of the gas suction conduit is heated almost uniformly, even when the height of the chimney reaches 50 m, the exhaust gas sample can be transferred without becoming a drain. In addition, a gas heater and a mist filter were installed as a pretreatment device between the second gas analyzer and the lower end of the gas suction conduit, so that the mist filter was located on the flow side. This mistake 1 - The filter removes dust and mist from the exhaust gas sample, significantly reducing the amount of dust that sticks to the inner wall of the gas heater, reducing the possibility of poor heating performance of the gas heater itself, and replacing it. The period will be significantly extended. therefore.

Continuous automatic analysis of residual sulfur oxides after washing exhaust gas with water can be performed with a high degree of accuracy that satisfies the certification tolerance.In addition, the life of the mist filter's filter element and gas heater can be greatly extended. Continuous use for about a month is possible.

[Brief explanation of drawings]

FIG. 1 is a piping diagram of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an extraction line, and FIG. 3 is a vertical sectional view of a mist filter. 1: Chimney, 2: Gas extractor, 3: Gas suction conduit, 4: Jacket pipe, 6: Steam pipe (heat medium 4 pipes)
, 8: Drain removal pipe, 11: Heat insulation layer, 15: Pretreatment pipe, 18: Mist filter, 23: Gas heater,
25: Feed pipe, 26: Pump. Patent Applicant Toyobo Co., Ltd. Agent Patent Attorney Takeshi Sakano Daikichi 1) Tsukasa Ryo

Claims (1)

[Scope of Claims] [1] A gas sampling device is provided near the top of the chimney equipped with a water washing desulfurization device for exhaust gas, and a gas suction pipe for jacketing is provided along the entire length of the gas suction conduit that is connected to the gas sampling device and extends to near the ground. A heat medium conduction pipe is connected to this jacket pipe, the outer surface of the jacket pipe is further covered with a heat insulating material, and the inlet of the gas heater located on the ground is connected to the above gas suction pipe. 1. A device for collecting exhaust gas samples in a chimney, characterized in that a mist filter is interposed in a pretreatment pipe, and a gas analyzer is connected to an outlet of the gas heater via a feed pipe and a pump. [2] The apparatus for collecting exhaust gas samples in a chimney according to claim 1, wherein a plurality of heat medium conducting pipes are connected to the jacket pipe at predetermined intervals. [3] The device for collecting exhaust gas samples in a chimney according to claim 1 or 2, wherein the heating medium is steam. [4] The temperature of the heat medium in the jacket pipe is 150 to 16
A device for collecting an exhaust gas sample in a chimney according to any one of claims 1 to 3, wherein the temperature is 0°C. [5] The filter element of the mist filter has a thickness of 0.
5. The device for collecting an exhaust gas sample in a chimney according to any one of claims 1 to 4, which is a nonwoven fabric having a porosity of 10 to 40% and made of synthetic fiber filaments of 5 to 5 deniers.