JP3100235B2 - Flue gas sampling probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flue gas sampling probe.

[0002]

2. Description of the Related Art For example, flue gas discharged from power plants, large-scale factories, etc., emits dust, sulfur oxides (SOx), nitrogen oxides (NOx), hydrogen chloride, etc., which are substances causing air pollution. In order to prevent air pollution, those who emit these substances are legally required to measure their emissions (see Article 16 of the Air Pollution Control Act).

[0003] Among these monitored objects, gases such as sulfur oxides (SOx), nitrogen oxides (NOx), and hydrogen chloride are used to filter dust from a gas that is quantitatively sucked from a flue via a sampling probe. After removal, it is led to a component analyzer such as an infrared analyzer to measure the concentration. Normal,
The flue gas that has passed through the component analyzer has been removed of the harmful substances described above, and can be released into the atmosphere as it is, but can be returned to the flue again.

[0004] Dust is a solid substance, and as a method for measuring the concentration in flue gas, Japanese Industrial Standard (JIS) Z
The filtration and trapping method specified in 8808 (Method of measuring dust concentration in exhaust gas) is the standard, but a light transmission type monitor that measures the amount of transmitted light is a monitor that can continuously measure the concentration of dust. A light scattering type for measuring the amount of light scattered by dust (see Japanese Patent Publication No. 53-28234 and Japanese Patent Application Laid-Open No. 62-274244), a β-ray absorption type for measuring the absorbed β dose, a contact charging A contact charging type for measuring the amount has been proposed.

[0005] A monitor capable of continuously measuring the concentration of dust is provided with a filter at a subsequent stage to remove the dust in order to prevent flue gas containing harmful components from being discharged out of the flue as it is. Removing harmful gas components such as SOx, NOx, and hydrogen chloride by adsorption, etc., and then releasing them into the atmosphere, and returning the measured flue gas to the flue again by the dynamic pressure of the flue gas or an air pump. doing.

Up to now, the gas component measuring device using the above-mentioned component analyzer and the solid component monitor have been separately manufactured and separately assembled in a flue.

[0007]

Therefore, in order to install them, two holes with different positions are made in the flue,
It is necessary to install a gas component measuring device on one side and a dust component monitor on the other side, which increases installation costs and greatly restricts these installation locations due to piping etc. installed near the flue. It is not uncommon.

[0008] The present invention has been made in view of the above circumstances, and it is possible to install a device for measuring a gas component and a device for measuring a dust component at low cost, and furthermore, it is possible to freely select these installation locations. It is an object of the present invention to provide a flue gas sampling probe with an increased degree.

[0009]

According to the present invention, as shown in, for example, FIG.
Assuming a flue gas sampling probe having a probe body 4 which is connected to the component analyzer 3 via the filter unit 2 outside, the following measures are taken in order to achieve the above object.

That is, the dust concentration measuring section 6 provided outside the flue 1 and in front of the filter section 2 and the portion of the probe main body 4 outside the flue 1 and the dust concentration measuring section 6 are heated and It is characterized by comprising a heating device 9 for preventing condensation of moisture in the dust measurement section 6.

[0011]

In the present invention, after the dust of the flue gas is measured by the dust measuring section 6, the dust is removed from the flue gas by the filter section 2 and guided to the component analyzer 3, where the dust is measured. The concentration of the gas component is measured.

Therefore, a probe for extracting flue gas from the flue for measuring the gas component concentration is also used as a probe for extracting flue gas for measuring the dust concentration, and the flue 1 has one hole for inserting a probe. Only be formed.

In addition, a filter for removing dust from flue gas for measuring gas component concentration is also used as a filter for removing dust from flue gas released into the atmosphere after measuring dust concentration. The component analyzer for measurement is also used as a means for removing harmful gas components from the flue gas released into the atmosphere after measuring the dust concentration.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flue gas sampling probe according to one embodiment of the present invention will be described below with reference to FIGS.

This flue gas sampling probe is used for a monitor for measuring the concentration of flue gas dust, SOx, NOx, hydrogen chloride and the like. As shown in the configuration diagram of FIG. And a probe main body 4 whose other end is connected to the component analyzer 3 via the filter unit 2 outside the flue 1 at the other end.

A dust concentration measuring unit 6 is provided between the probe body 4 and the filter case 5 housing the filter unit 2.
A measurement chamber 7 communicating with the inside of the flue 1 via the probe main body 4 and communicating with the inside of the filter case 5 is formed in the dust concentration measuring section 6.

The portion of the probe body 4 outside the flue 1, the dust concentration measuring section 6 and the filter case 5 are housed in a heat insulating box 8 having heat insulating properties. 9 are provided.

The heater 9 is provided to prevent moisture contained in the flue gas from condensing in the portion of the probe body 4 outside the flue 1 and inside the dust concentration measuring section 6, and therefore, the heat insulation box What is necessary is just to heat the inside of 8 to about 110-150 degreeC.

If the temperature of the heater 9 is lower than 110 ° C., the moisture contained in the flue gas may condense inside the portion of the probe body 4 outside the flue 1 or inside the dust concentration measuring section 6, which is not preferable. When the temperature of the heater 9 exceeds 150 ° C., the effect of preventing coagulation is not further enhanced,
As well as wasting energy, the probe body 4
It is not preferable because the heat loads of the dust concentration measurement unit 6, the filter case 5, and the like become excessive.

As shown in the cross-sectional view of FIG. 2, the dust concentration measuring section 6 includes an optical fiber 10 for projecting light from a light source outside the heat insulating box 8 toward the center of the measuring chamber 7, The light emitting optical axis of the light projecting optical fiber 10 and the light receiving optical axis of the light receiving optical fiber 11 are provided with a light receiving optical fiber 11 for guiding the scattered light in the central part in the measurement chamber 7 to the optical sensor outside the heat insulating box 8. Are intersected with each other at an angle of, for example, 120 ° on the center axis of the measurement chamber 7, and the light beam passing through the center of the measurement chamber 7 is located on the emission optical axis of the light projecting optical fiber 10. Trap 12 for preventing irregular reflection on the peripheral surface of
Is provided on the light receiving optical axis of the light receiving optical fiber 11.
The light irregularly reflected on the peripheral surface of the measurement chamber 7
An optical trap 13 is provided to prevent the light from being incident on the light source.

The light projecting optical fiber 10 is supported on a peripheral wall of the measuring chamber 7 via a holder 14, and a light guide 15 formed in the holder 14 is provided with a lens 16 for converging light. An air supply path 17 is connected to the light guide path 15, and the lens 16 and the optical fiber 10 are cooled by air ejected from the air supply path 17, and dust from the measurement chamber 7 is passed through the light guide path 15. An air curtain for preventing the light from reaching the lens 16 and being attached thereto is formed in the light guide path 15.

Similarly, the light receiving optical fiber 11 is also
Is supported by the peripheral wall of the measurement chamber 7 via a light guide, and a lens for converging light is provided in a light guide path formed in the holder 18,
An air supply path 19 is connected to the light guide path to form an air curtain for cooling the lens 16 and the optical fiber 11 and preventing dust from entering the light guide path from the measurement chamber 7.

As shown in the sectional views of FIGS. 1 and 3, most of the probe main body 4 is housed in a heat insulating sleeve 20 fixed to a heat insulating box 8. Filter case 5
A filter chamber 21 is formed coaxially with the probe main body 4 and the measurement chamber 7, and a filter element 22 made of glass wool or the like is arranged to be shifted toward the measurement chamber 7 in the filter chamber 21. Is done.

A communication passage 23 for communicating the filter chamber 21 with the component analyzer 3 is led out from a lower portion of the filter chamber 21 on the side opposite to the measurement chamber. The component analyzer 3 includes a heating conduit 3 for sampling flue exhaust gas from the probe body 4.
a, but only a joint in which the upper end of the heating conduit 3a is fitted is shown in the drawings.

Although not shown, an electronic circuit for controlling the monitor, a control box containing the light source and the optical sensor are arranged above the heat insulating box 8, and the monitor is operated on one side. An operation panel for performing the operation is provided.

In this monitor, when the vacuum pump of the component analyzer 3 is operated, the flue gas in the flue 1 passes through the probe body 4, the measurement chamber 7, the filter chamber 21, and the communication passage 23, and the component analyzer 3 Is sucked.

In the measuring chamber 7, light is emitted from the light source toward the center of the measuring chamber 7 from the light emitting optical fiber 10, and light scattered by dust passing through the center of the measuring chamber 7 is used for light receiving. The light is received by the optical sensor via the optical fiber 11. Then, the control circuit calculates and records the dust concentration in the flue gas based on the amount of light received by the optical sensor,
For example, it is displayed by a display means provided on the operation panel as needed.

A portion of the probe body 4 located inside the flue 1 is heated by the flue gas, and a portion of the probe body 4 located outside the flue 1 and the measuring chamber 7 are heated by a heater 9 in an insulating box 8. Since it is heated to 110 ° to 150 °, there is no possibility that moisture will condense inside the probe main body 4 and the measurement chamber 7, and the dust concentration will not be erroneously detected due to the adsorption of the dust to the flocculated water. When the temperature inside the furnace varies greatly in a batch-operated combustion furnace or the like, the probe portion protruding into the flue 1 is also heated by the heater.

Further, since the light source and the optical sensor are arranged outside the heat insulation box 8, it is prevented that the heat source and the light sensor are deteriorated by being heated by the heater 9 in the heat insulation box 8, thereby shortening the service life. The flue gas that has passed through the measurement chamber 7 is removed from the dust by the filter unit 2 in the filter chamber 26, and then guided to the component analyzer 3, where the concentration of SOx, NOx, hydrogen chloride, and the like is measured.

In this monitor, the gas component SO
The probe body 4 for extracting flue gas from the flue for measuring the concentration of x, NOx, hydrogen chloride, etc. is also used as the probe body 4 for extracting flue gas from the flue for measuring dust.

Therefore, it is not necessary to provide two probes for measuring the concentration of the gas component and the concentration of the dust, and only one probe insertion hole is formed in the flue. Installation costs are halved.

Further, in this monitor, the probe main body for measuring the gas component concentration is also used as the probe main body for measuring the dust concentration, and the filter provided before the measurement of the gas component concentration is a filter for removing dust after measuring the dust concentration. A component analyzer for measuring a gas component concentration is also used as a harmful gas component removal device after measuring a dust concentration.

Therefore, compared to the prior art in which a monitor for measuring the concentration of dust and a monitor for measuring the concentration of gaseous components are installed, the whole monitor can be made small and compact, and the installation location is restricted by pipes near the flue. And the degree of freedom in selecting the installation location is increased.

Further, since the number of parts of the whole monitor can be reduced and the structure is simplified, the whole monitor can be inexpensive. In the above embodiment, the light scattering method of measuring the amount of light scattered by the dust is adopted as the method of measuring the dust concentration, but instead, the light transmission method of measuring the amount of transmitted light, the β-ray It is possible to adopt a β-ray absorption method for measuring the β dose absorbed by irradiation or a contact charging method for measuring the contact charge amount.

[0035]

As described above, according to the present invention,
It is possible to measure the concentration of dust and the concentration of gas components in flue gas collected from the flue via one probe.

Therefore, it is not necessary to provide two probes for measuring the concentration of the gas component and the concentration of the dust, and only one probe insertion hole is formed in the flue. Installation costs are halved.

Further, the probe for measuring the gas component concentration is used also as the probe for measuring the dust concentration, and the filter provided at the preceding stage of the measurement of the gas component concentration is also used as the filter for removing dust after the measurement of the dust concentration. Since the component analyzer for concentration measurement is also used as a device for removing harmful gas components after measuring the dust concentration, the monitor as a whole is smaller than the conventional technology in which a monitor for measuring the concentration of dust and a monitor for measuring the concentration of gas components are installed. The size of the monitor can be reduced, the number of parts can be reduced, and the structure can be simplified. So
The whole monitor can be inexpensive.

Further, in the present invention, in particular, the heating device has a heat insulating box surrounding the probe main body and the dust measuring section, and a heater for heating the inside of the heat insulating box. A light emitting optical fiber for introducing light from a light source outside the heat insulation box into the measurement chamber, and a light receiving optical fiber for guiding light from the measurement chamber to an optical sensor outside the heat insulation box, the measurement light chamber having a measurement chamber communicating with the filter; In this case, it is possible to prevent the light source and the optical sensor from deteriorating due to the heat of the heating device to shorten their life.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view of a main part of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flue 2 Filter part 3 Component analyzer 4 Probe main body 6 Dust concentration measuring part 7 Measurement room 8 Insulation box 9 Heater 10 Optical fiber 11 Optical fiber

Continuation of the front page (72) Inventor Harumichi Shibata 5-5-5 Hongo, Bunkyo-ku, Tokyo (72) Inventor Masao Abe 3608-3, Kashiwada-cho, Ushiku-shi, Ibaraki Pref. (JP, A) JP-A-54-99485 (JP, A) JP-A-59-100841 (JP, A) JP-A-49-1288 (JP, A) JP-A-53-76088 (JP, A) 57-108149 (JP, U) U.S. Pat. No. 3,874,902 (US, A) French Patent Application 2036476 (FR, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 1/00 -1/28 G01N 21/00-21/61

Claims (1)

(57) [Claims] 1. One end protrudes into the flue and the other end is outside the flue.
In the flue gas sampling probe to be connected to the component analyzer, to the flue gas sampling the probe, measuring dust concentration
And a filter for removing dust at a stage subsequent to the dust concentration measuring section.
A filter case for accommodating the filter unit, and accommodating the dust concentration measurement unit and the filter case.
The dust concentration measurement unit and the filter case
Is heated to the inside of the dust concentration measurement section and the filter case.
A flue gas sampling probe, comprising: a heating device for preventing condensation and condensation of moisture in the flue gas.