JP2001330540A - Method of collecting sample gas for exhaust gas analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably perform on-line gas analysis while minimizing a time leg depending on sampling systems by preventing sample collecting lines from plugging with dust by using a simple structure when analyzing gas composition on-line. SOLUTION: Water vapor is generated by heating water in drain pots 16 and 17 for collecting mist removed from the sample gas. The water vapor is returned to sample pipes 12 and 13 for sample gas suction to be condensed or fine dust in the sample gas, thereby removing the dust.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a converter and the like,
The present invention relates to a method for analyzing a flue gas component on-line and stably collecting a sample gas from a flue, which is suitable for use in flue gas recovery equipment, estimation of molten steel component, or flue explosion monitoring.

[0002]

2. Description of the Related Art Conventionally, sample gas sampling for on-line analysis of converter exhaust gas has various filters in its sampling path for the purpose of improving the accuracy of analysis values in an exhaust gas analyzer and stably operating the analyzer itself. Provided, particle size several μm
Above dust is removed.

However, the dust in the converter exhaust gas is
The amount of the generated gas is extremely large, and the filter provided in the collection path is also immediately clogged, so that the sample gas cannot be collected.

[0004] In general, in order to prevent this, the sampling system is duplicated, and the sampling system is switched at regular time intervals. In addition, long-term sample gas sampling is performed.

FIG. 3 shows an example of a typical gas analysis sampling system.

In FIG. 1, a sample gas is introduced into a sample pipe 12 from a sampling probe 10, and is sucked by a suction pump 18 through a mist filter 14. The sampling probe 10 is a filter, in which dust in the sample gas is first removed. The sampling probe 10 is heated to 100 ° C. or higher by a heater, and the sample pipe 1
The sample gas is cooled in two paths, and the mist is removed by the mist filter 14, and at the same time, the fine dust is removed.
The mist removed by the mist filter 14 is collected in a drain pot 16.

[0007] The sample gas dehumidified by the gas cooler 20 is then finally removed by a membrane filter 22 to remove ultra-fine dust.
After passing through 4 and 25, they are led to a gas analyzer 26 for analyzing oxygen (O2) and a gas analyzer 27 for analyzing carbon monoxide (CO), respectively.

At this time, the sampling probe 10, the sample pipe 12, the mist filter 14, and the drain pot 16 are another system (the sampling probe 11, the sample pipe 13, the mist filter 15, and the drain pot 17).
Is provided. Then, at regular intervals, the sample system switching valves 28, 29, 30, 3
1, 32, and 33, the backwashing purge is performed by the purge gas introduced by the purge valves 36, 37, 38, and 39 through the filter regulator 34 on the one hand and the dust adhering to the filter on the other hand. Has been removed.

In FIG. 1, reference numeral 40 denotes a suction pump for purging gas, and reference numeral 42 denotes a fin negative pressure gauge for detecting blockage of a filter.

[0010]

However, according to the conventional method shown in FIG. 3, fine particles having a particle size of 10 μm or less cannot be completely removed from the sampling probes 10 and 11, and eventually, Often causes clogging of the filter, and as a result, analysis becomes impossible. Filter holes in the sampling probe itself,
If the filter is made finer, clogging of the filter at the subsequent stage can be avoided, but the sampling probe itself is clogged immediately, and as a result, continuous and stable online analysis cannot be performed.

For example, it is possible to remove fine dust to some extent by preparing a pot filled with water and passing a sample gas through the pot, but in this case, the sampling time becomes longer and the exhaust gas is recovered. In control, etc.
This has the problem that it leads to operational losses.

As similar to the present invention, Japanese Patent Application Laid-Open No. Hei 10-260119 discloses a method in which solid particles in a sample gas are caused to flow down by being provided on a wet wall and contacting the flowing water with the sample gas on the wet wall. It is described that the material is removed by moving to water, but a new tall wet wall needs to be provided.

[0013] In addition, in Japanese Utility Model Laid-Open No. 7-5045, a water ejector connected to a gas introduction pipe, a water circulation pipe connected to the water ejector, and a steam separator sent to the water circulation pipe are provided. It is described that while spraying water into a water washer, water is pumped from a water part of a steam separator to a water ejector via a water circulation pipe by a pump, but equipment such as a water ejector and steam separator is also described. And the configuration is complicated.

Japanese Patent Application Laid-Open No. 9-187615 discloses that a gas fluid containing fine dust is sprayed with steam having a higher temperature and a higher pressure than the gas fluid, and the steam is agglomerated with the fine dust as a core.
It is described that the enlarged droplets are removed, but it is not applied to sample gas collection.

The present invention has been made to solve the above-mentioned conventional problems, and has a simple structure to remove fine dust that cannot be removed by a sampling probe and to reduce exhaust gas without extending sampling time. The goal is to achieve a long-term stable operation of online analysis.

[0016]

SUMMARY OF THE INVENTION According to the present invention, when a sample gas of an exhaust gas analyzer is collected, water in a drain pot for collecting mist removed from the sample gas is heated to generate steam, and the sample gas is sucked. The above problem has been solved by returning to a sample pipe for use, whereby water vapor is condensed and removed from fine dust in the sample gas.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In this embodiment, as shown in FIG. 1, in a gas analysis sampling system similar to the conventional example shown in FIG. 3, a drain pot 16, which collects the mist removed from the sample gas by the mist filters 14, 15, is provided. And water supply pipes 50 and 51 for guiding water from the water supply pipe 17.
For example, band heaters 52 and 53 are wound around 0 and 51 to heat water to generate water vapor, and the generated water vapor is supplied to sample piping 1 by heat retaining pipes 54 and 55 that have been subjected to heat retaining treatment.
2, 13 are connected to connection points 12A, 13A.

The water guide pipes 50 and 51 have a slight pressure difference due to the influence of the sampling suction pumps 18 and 19, but have a water level almost equal to the level of the drain pots 16 and 17.

The connection points 12A and 12B of the heat retaining pipes 54 and 55 to the sampling pipes 12 and 13 are located as close to the sampling probes 10 and 11 as possible.

As a result, water vapor is added to the sample gas at the connection points 12A and 12B. However, the paths of the sample pipes 11 and 12 from the connection points 12A and 12B to the mist filters 14 and 15 Because
The added water vapor condenses with the fine dust in the sample gas as a core. The water that has condensed into water droplets is collected in the drain pots 16 and 17, and as a result, fine dust in the sample gas can be removed.

The means for heating the water in the drain pot introduced into the water pipe is not limited to the band heater.

[0023]

FIG. 2 shows an embodiment in which the present invention is carried out in a steel mill having two 160-ton top-bottom blowing converters. As the converter equipment, the blowing time is 90 to 120 minutes, and the converter exhaust gas recovery equipment (Oxygen Converter Gas Recovery System)
em: hereinafter abbreviated as OG) The gas sampling probes 10 and 11 are attached to the emission chimney 60, and the exhaust gas component in the flue 61 is monitored by the analyzer 70. ) An explosion is avoided by the nitrogen purge introduced from the supply line 62.

The analyzer 70 includes suction pumps 18 and 1
9 is disposed downstream of the cooler 20 and the filter 22, and a CO spectrometer 27 of, for example, an infrared spectroscopic type and an O2 spectrometer 26 of, for example, a magnetic type are connected in series in this order. Different from 1.

In the figure, 64 is a flow rate control valve for purge gas, 66 is a flow rate transmitter (FT), 68 is an on-off valve, 72
Is a switching / backwash sequence for switching the sampling system and performing purging by backwashing, 80 is a flow rate control valve (FICA) 82 for purge gas, a leakage valve / bypass valve leak detection sequence 84, and an air leak detection sequence 8
6. OG emergency stop device (existing) 88, analyzer monitor screen 9
0, an OG digital control device (OG DCS) containing an annunciator message 92.

The B0 to B2 purges are all purges to the OG flue and are labeled A, B and C from the upstream of the flue, and the B purge indicates a purge to the emission chimney 60.

As a result of applying the present invention to this equipment, there is no period during which exhaust gas analysis cannot be performed, equipment safety is improved, and the repair cost of the analyzer is reduced by 10%.

In the above description, the present invention has been applied to an explosion avoidance system of a steel mill having two upper-bottom blow converters, but the present invention is not limited to this. Obviously, the present invention can be similarly applied to exhaust gas analysis of converters other than blown converters and other equipment / systems.

[0029]

According to the present invention, for dust removal,
The fine dust in the sample gas can be removed without providing a new device in the sampling path or making the sampling path long. Therefore, it is possible to prevent various filters installed in the sampling path from being clogged with dust while keeping the sampling time at the same level as before.

As a result, the long-term stable operation of the exhaust gas analyzer can be achieved, and the safety of the equipment can be improved. Further, the frequency of maintenance of the exhaust gas analyzer can be reduced, and the repair cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a pipeline diagram showing an embodiment of a gas analysis sampling system according to the present invention.

FIG. 2 is a pipeline diagram showing the configuration of an embodiment of the present invention applied to a steelmaking plant having two 160-ton top-bottom blow converters.

FIG. 3 is a pipeline diagram showing an example of a conventional gas analysis sampling system.

[Explanation of symbols]

 10, 11 ... sampling probe 12, 13 ... sample pipe 14, 15 ... mist filter 16, 17 ... drain pot 18, 16, 40 ... suction pump 26, 27 ... gas analyzer 50, 51 ... water pipe 52, 53 ... band Heaters 54, 55 ... heat insulation pipe

Claims (1)

[Claims] When collecting a sample gas of an exhaust gas analyzer, water in a drain pot for collecting mist removed from the sample gas is heated to generate steam and returned to a sample pipe for sample gas suction. A method for collecting a sample gas of an exhaust gas analyzer, wherein water vapor is condensed and removed from fine dust in the sample gas.