JPH0681027A - Exhaust gas sampling device in vacuum refining furnace - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an exhaust gas sampling apparatus capable of stably sampling exhaust gas even under high vacuum. [Structure] Prefilters PF, PF are arranged and sealed on the intermediate parts 511, 511 of the probes 51, 52 projecting in the exhaust duct 2, and the rear lids 510, 510 are attached, and the exhaust gas purifying device 6 and the purging device 7 and the massage structure pipe are attached. Connect via 81,81,82,82.
The exhaust gas purifying device 6 has filters F ₁ and F ₂ built-in, and a filter 66 is disposed via vacuum device joints 9 and 9.
The exhaust gas purification device 6 is connected to the analysis device 4 for analyzing the components of the filtered exhaust gas via a kneading structure pipe 83. A line 70 from the purging device 7 is provided at both ends of the filter 66.
3,704 are connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for collecting exhaust gas discharged from a vacuum refining furnace during the vacuum refining process.

[0002]

2. Description of the Related Art Since the amount of carbon in steel has a great influence on the quality and mechanical strength of steel, it is important to match the carbon content with the target value in the vacuum refining process. As a method for controlling the carbon content, a dynamic control method based on the component analysis value of the exhaust gas discharged from the vacuum refining furnace is widely used.

As an apparatus for analyzing exhaust gas components from a vacuum refining furnace, an apparatus for analyzing exhaust gas components at a normal pressure (760 Torr) is known. This equipment samples atmospheric pressure exhaust gas on the outlet side of a vacuum pump (booster or ejector pump) installed away from the vacuum refining furnace, and analyzes its components with a mass spectrometer or infrared type analyzer. It is designed to be analyzed.

However, in such an analyzer, it takes a long time to move the exhaust gas, so that it is difficult to obtain a timely analysis result with time.

Further, a system for introducing exhaust gas into the mass spectrometer is provided with a valve mechanism whose conductance is variable,
A device that continuously analyzes the components of exhaust gas is
It is disclosed in Japanese Patent Publication No. 85. The analyzer disclosed herein will be briefly described below.

FIG. 4 is a schematic diagram showing the structure of this analyzer. In the figure, 31 is connected to a vacuum refining furnace (not shown) and is an exhaust duct which is a flue for exhausting exhaust gas from the vacuum refining furnace. Is. In the exhaust duct 31, a gas sampling pipe 32 for collecting a part of the exhaust gas is provided so as to project.
The end of 32 is connected to a mass spectrometer 33 which analyzes the components of the exhaust gas. In the gas sampling pipe 32, three valves 34a, 34b, 34c having different conductances are interposed in parallel, and one of them is measured by a measurement signal from a vacuum gauge 35 installed in the exhaust duct 31. Any valve can be selected and opened. In addition, the valves 34a, 34b,
A dust trap 36 for filtering dust is interposed in the gas sampling pipe 32 on the upstream side of the interposed position of 34c. Further, in the gas sampling pipe 32, from the upstream side to the downstream side thereof, two vacuum pumps 37, 37 for introducing the exhaust gas discharged from the exhaust duct 31 into the mass spectrometer 33 and the mass spectrometer 33 are exhausted. An exhaust pump 38 for performing the operation is provided in this order.

In the apparatus having such a structure, the exhaust duct 31
The exhaust gas is introduced into the mass spectrometer 33 through the gas sampling pipe 32 and the components of the exhaust gas are continuously analyzed. At this time, the pressure in the exhaust duct 31 is measured by the vacuum gauge 35, and the valve having the optimum conductance is selected from the three valves 34a, 34b, 34c based on the measured value.
The pressure of the exhaust gas introduced into the
It is possible to analyze the components of the exhaust gas.

[0008]

By the way, in order to actually dispose such a conventional device in the exhaust duct and to collect a part of the exhaust gas, it is necessary to use a normal pressure at the start and a high vacuum thereafter. In the environment of vacuum refining, it becomes possible to collect exhaust gas that is very hot and contains a large amount of dust and that has high humidity.
The device must be configured.

That is, when collecting the exhaust gas under a high vacuum, when the outside air is sucked from the gas sampling pipe 32 communicating with the mass spectrometer 33 from the exhaust duct 31, accurate analysis can be performed by the mass spectrometer 33. It will be a big problem. If the gas sampling pipe 32 is a single pipe having no connecting portion, the above problem does not occur. However, in that case, the clogging of the dust trap 36 due to the dust in the exhaust gas and the contamination of the pipe between the collection port and the dust trap 36, or the clogging of the gas collection pipe 32 due to the condensed water from the high temperature and high humidity exhaust gas, etc. should be dealt with. Therefore, it is impossible to obtain a stable exhaust gas.

On the other hand, in the case of adopting the structure through the connecting portion to solve this problem, for example, the vibration is transmitted from the vacuum refining furnace during the vacuum refining, so that the joint is loosened, so that the intake of the outside air may occur. . The present invention has been made in view of such circumstances, and an object of the present invention is to provide an exhaust gas sampling apparatus that can stably collect exhaust gas even under a high vacuum.

[0011]

An exhaust gas collecting apparatus according to a first aspect of the present invention is a probe for collecting exhaust gas discharged during vacuum refining, and an analysis for purifying the exhaust gas collected by the probe to analyze the components of the exhaust gas. In the exhaust gas collecting device having an exhaust gas purifying device to be introduced into the device, the probe and the exhaust gas purifying device are detachably provided with a filter for removing dust in the exhaust gas, and a sealing means for preventing intake of outside air to the detached portion. It is characterized by having.

Further, in the exhaust gas collecting apparatus according to the second aspect of the present invention, purge gas flows from the exhaust gas purifying apparatus to the probe in the probe direction, and purge gas flows from the analyzing apparatus to the exhaust gas purifying apparatus in the exhaust gas purifying apparatus. It is characterized in that the purging devices for flowing through are respectively connected.

Further, an exhaust gas collecting apparatus according to a third aspect of the present invention is a probe for collecting the exhaust gas discharged during vacuum refining, and an exhaust gas for introducing into the analyzer for purifying the exhaust gas collected by the probe and analyzing the components of the exhaust gas. In an exhaust gas sampling device including a purifying device, the probe and the exhaust gas purifying device, and between the exhaust gas purifying device and the analyzing device are connected by a kneading structure pipe that absorbs vibrations, To do.

[0014]

In the first aspect of the invention, since the filter is detachably attached, if the filter is clogged, the filter can be easily replaced, and since the detached portion is provided with the sealing means, even under high vacuum. There is no danger of inhaling outside air.

In the second aspect of the invention, the probe and the exhaust gas are passed by passing the purge gas through the probe from the exhaust gas purifying device toward the probe and through the exhaust gas purifying device toward the exhaust gas purifying device toward the exhaust gas purifying device. Dirt accumulated on the filter equipped with the purifying device can be removed, and exhaust gas does not enter the standby probe.

In the third aspect of the invention, since the probe, the exhaust gas purifying device and the analyzing device are connected through the kneading structure pipe, vibration generated in each device is absorbed and loosening of the connecting portion is prevented.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a block diagram showing an outline of an exhaust gas collecting apparatus according to the present invention. Reference numeral 1 in the figure is a vacuum refining furnace for accommodating a ladle (not shown) containing molten steel therein and for refining the molten steel in a vacuum. And exhaust duct 2 in vacuum refining furnace 1
The vacuum pump 3 is connected via. The exhaust gas discharged during the vacuum refining is exhausted through the exhaust duct 2 by the vacuum pump 3 in the direction of the white arrow in the figure.

In such a vacuum refining apparatus, in order to analyze the components of the exhaust gas, the exhaust duct 2 is penetrated with probes 51, 52 as exhaust gas sampling ports.
Is an exhaust gas purification device 6 that removes fine dust in the exhaust gas
Is connected via a kneading structure pipe 80 that absorbs vibrations, for example, a flexible pipe, and the exhaust gas purifying apparatus 6 is similarly connected to the kneading structure pipe 80.
It is connected via 80 to the exhaust gas analyzer 4 for analyzing the components of the exhaust gas.

On the other hand, a line from the purging device 7 is provided at the end portion of the probes 51, 52 on the exhaust gas purifying device 6 side.
Further, a line from the purging device 7 is opened on the line of the exhaust gas purification device 6 on the analysis device 4 side. Then, the purge gas is passed from the purging device 7 to remove dust adhering to the probes 51, 52 and the exhaust gas purifying device 6 and to purge the probes 51, 52.

The device thus configured will be described in more detail with reference to FIG. 2 showing an example thereof. FIG. 2 is a schematic diagram showing the configuration of an exhaust gas sampling apparatus in which two probes 51, 52 penetrate the exhaust duct 2. In the figure, 51 and 52 are probes for collecting exhaust gas exhausted in the arrow direction in the figure,
The probe 51 is projectingly provided in the exhaust duct 2 so that the probe 51 is upstream in the exhaust direction and the probe 52 is downstream in the exhaust direction. One end of the cylindrical probe 51 (52) is projected into the exhaust duct 2, and the other end is detachably attached with a lid 510 (520).
And the line leading to the exhaust gas purification device 6 is connected to the lid 510 (520).
A line 701 (702) leading to the 601 (602) and the purging device 7 is established.

The intermediate portion 511 (521) from the attachment portion of the lid 510 (520) to the exhaust duct 2 has a double structure in which cooling water flows back, and the attachment portion is relatively large in the exhaust gas. A heat-resistant prefilter PF (PF) with a diameter of 10 μm to 20 μm for removing dust is inserted, and it is inserted between the prefilter PF (PF) and the intermediate part 511 (521) and between the prefilter PF (PF) and the lid 510.
A seal S such as a heat-resistant O-ring or packing is provided between the (520) and the (520) to prevent intake of outside air.

Exhaust gas containing a large amount of dust is collected from the probe 51 having the above-described structure, and at this time, relatively large dust is collected by the pre-filter PF installed on the probe 51. Since the collected dust gradually accumulates in the pre-filter PF, there is a risk that clogging will occur and stable exhaust gas collection will not be possible. Therefore, the exhaust gas is sampled from the probe 52, which was operated by operating the valve before the occurrence of clogging, and the sampling from the probe 51 is stopped. And the probe
The line 51 is regenerated by spraying a purge gas onto a pre-filter PF from a line 701 from a purging device which will be described later to backwash and prepare for the next exhaust gas collection.

On the other hand, when the clogging of the prefilter PF cannot be eliminated by backwashing with the purge gas, the prefilter PF is replaced, but the lid 510 of the probe 51 is removable, so the prefilter PF can be easily replaced. By the way, since the middle portion 511, the pre-filter PF, and the lid 510 are sealed as described above, there is no possibility that the outside air is sucked from these portions even under a high vacuum. In addition, since the exhaust gas is extremely hot, there is a risk that the intermediate portion 511 will expand and a gap will form between it and the lid 510, but the intermediate portion 511 has a double structure to allow cooling water to flow. Expansion is suppressed by the flowing cooling water.

The exhaust gas collected by the probes 51, 52 is sent to the exhaust gas purifying apparatus via the kneading structure pipes 81, 81. The main part of the exhaust gas purifying apparatus is a cartridge type filter 66 in which heat resistant filters F ₁ and F ₂ having a diameter of 1 to 2 mm are arranged.
Line 60, which is connected to lines 601, 602 at one end.
3 and a line 604 communicating the other end with the gas component analyzer 4.
And a vacuum device joint (for example, Swagelok). Lines 704 and 703 communicating with the purging device 7 are connected to the lines 603 and 604, respectively.

A line connected to the line 603 connected to the filter 66 and connected to the probe 51 and the probe 52, respectively.
Two air valves 101 and 10 are provided for 601 and line 602, respectively.
2,111,112 are respectively provided in series, and when the outside air is sucked in, these lines are closed to prevent the outside air from flowing into the analyzer 4. If two air valves are provided in series in this way, the reliability of preventing the inflow of outside air is increased.

Exhaust gas from which relatively large dust has been removed by the pre-filters PF, PF of the probes 51, 52 has finer dust removed by filters F ₁ , F ₂ arranged in the filter 66. After that, the gas is introduced into the exhaust gas component analyzer 13 such as a mass spectrometer or an infrared type analyzer through the inlet unit 12 for adjusting the conductance by the vacuum pumps 14, 14. At this time, since the exhaust gas is purified by the filter 66, the analysis value is stable and does not adversely affect the analyzer 13.

Contamination of the filters F ₁ and F ₂ due to the filtration of the exhaust gas is removed by spraying the purge gas from the analyzer 4 toward the exhaust gas purifier 6, and the purge gas containing the dirt is exhausted from the purge gas exhaust lines 704 and 705. If the clogging of the filters F ₁ and F ₂ cannot be eliminated by this, the filter 66 is replaced with a new one. At this time, since the joint for the vacuum device is used, the filter 66 can be easily replaced, but there is no risk of the outside air being sucked in under a high vacuum.

Although the filter is a cartridge type in the present embodiment, the present invention is not limited to this, and one or both ends of the filter may be a detachable lid like the probes 51 and 52 and may be sealed. Good. Such a probe
As described above, the lines from the purging device 7 are connected to the 51, 52 and the exhaust gas purifying device. Then, the purging device 7 operates as follows. First, when the exhaust gas is collected by the probe 51, a small amount of N ₂ gas, for example, as a purge gas is made to flow through the line 702 to the probe 52 on standby. Since the probe 52 has a positive pressure higher than that in the exhaust duct 2 due to the purge gas, the exhaust gas does not enter the probe 52, so that the probe 52 is not contaminated during standby.

In addition, the exhaust gas sampling from the probe 51 to the probe
In the case of replacing with 52, by flowing the purge gas through the probe 51, the pre-filter PF in the probe 51 can be backwashed even while the exhaust gas is being collected by the probe 52.
When the vacuum refining is completed, the pre-filter for both probes
Backwash PF and PF.

After the vacuum refining is completed, the purge gas is passed from the line 703 to the filter 66 of the exhaust gas purifying apparatus 6, the filters F ₁ and F ₂ are backwashed, and the purge gas containing dirt is exhausted from the lines 704 and 705. Further, purge gas is also passed through the lines 601 and 602 to remove the dirt adhering to both lines.

By the way, the lines 601, 602, 701, 702 connecting the probes 51, 52 and the exhaust gas purifying apparatus 6 are connected to the line 60 connecting the exhaust gas purifying apparatus 6 and the analyzer 4.
4 are provided with kneading structure pipes 81, 81, 82, 82, 83, respectively. This absorbs the vibrations generated in the respective devices and prevents the joints from loosening.

FIG. 3 shows the results obtained by continuously collecting exhaust gas during vacuum refining and analyzing the components by using the apparatus of the present invention having the above-described structure. As is apparent from FIG. 3, in the device of the present invention, the exhaust gas could be stably collected without sucking the outside air under the environment where the pressure greatly changes from about 760 Torr to 0.1 Torr.

[0033]

As described above in detail, in the apparatus of the present invention, the replacement of the pre-filter and the filter can be easily performed, so that the replacement work is efficient when clogging occurs, and the purge gas cleans the both filters. Since it can be removed, the life of the filter is extended and it is economical. Further, since the respective devices are connected through the kneading structure pipe, the loosening of the connection portion due to vibration is prevented, and thus the maintenance management of the connection portion is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an exhaust gas collecting apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of an exhaust gas collecting apparatus according to the present invention.

FIG. 3 is a graph showing the results of analysis of exhaust gas using the exhaust gas sampling apparatus according to the present invention.

FIG. 4 is a schematic diagram showing a configuration of a conventional exhaust gas collecting apparatus.

[Explanation of symbols]

1 vacuum refining furnace 2 exhaust duct 3 vacuum pump 4 exhaust gas analyzer 51,52 probe 6 exhaust gas purifier 7 purge device 601,602,603,604 line 701,702,703,704 line 9 joint 101,102,111,112 air valve 13 analyzer 14 vacuum pump 66 filter 81,82,83 kneading structure Tube PF Pre-filter F ₁ , F ₂ filter S seal

Claims (3)

[Claims] 1. An exhaust gas collecting apparatus comprising: a probe for collecting exhaust gas discharged during vacuum refining; and an exhaust gas purifying apparatus for purifying the exhaust gas collected by the probe and introducing it into an analyzer for analyzing components of the exhaust gas. The probe and the exhaust gas purifying apparatus are equipped with a filter for removing dust in exhaust gas so that they can be detachably attached, and the detaching portion is provided with a sealing means for preventing intake of outside air. 2. A purging device is connected to the probe for flowing a purge gas from the exhaust gas purifying device toward the probe, and to the exhaust gas purifying device for flowing a purge gas from the analyzer toward the exhaust gas purifying device. The exhaust gas collecting apparatus according to claim 1, which is provided. 3. An exhaust gas collecting apparatus comprising a probe for collecting exhaust gas discharged during vacuum refining, and an exhaust gas purifying apparatus for purifying the exhaust gas collected by the probe and introducing it into an analyzer for analyzing the components of the exhaust gas. An exhaust gas collecting apparatus, wherein the probe and the exhaust gas purifying apparatus and the exhaust gas purifying apparatus and the analyzing apparatus are connected by a kneading structure pipe that absorbs vibration.