JPH10260119A - Pre-treating device for gas analysis - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pre-treating device for gas analysis which can enable a gas analyzer to continuously perform analysis. SOLUTION: A sample gas is introduced to the upper pot 21 of a first stage A and then sent downward through a wetted wall 22. When flowing-down water comes into contact with the sample gas on the wall 22, solid particles contained in the sample gas move to the water. The sample gas is then extracted through the top of a first circulating tank 23, introduced to the upper pot 24 of a second stage B, and sent downward through another wetted wall 25. When the sample gas is sent downward, the gas and water are forcibly sent downward by means of a pot 26 equipped with an aspirator. The sample gas then reaches the upper pot 28 of a third stage C and is subjected to the same treatment as that performed in the second stage B. After the third stage C, the sample gas reaches the upper pot 32 of a fourth stage D and is subjected to the same treatment as that, in the first stage A. The sample gas from which solid particles are completely removed through the treatment in the four stages is sent to a gas analyzer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a gas analyzer for analyzing the oxygen concentration in a gasifier for pyrolyzing wastes to generate a flammable gas, the gas being analyzed. The present invention relates to a gas analysis pretreatment device for removing solid particles therein.

[0002]

2. Description of the Related Art Waste such as municipal solid waste and industrial waste is pyrolyzed in a gasification furnace, and the combustible gas generated is guided to a melting furnace for combustion. BACKGROUND ART A waste gasification / melting apparatus that recovers heat of exhaust gas with a waste heat boiler has been conventionally known. In this waste gasification and melting apparatus, the oxygen concentration in the gasification furnace is continuously analyzed by a gas analyzer in order to prevent a furnace explosion due to an increase in the oxygen concentration in the gasification furnace. The furnace gas contains a large amount of solid particles such as tar and dust, and a gas analysis pretreatment device for removing these solid particles is provided upstream of the gas analyzer.

[0003] As a conventional gas analysis pretreatment device, a dust collector and a filter are generally used.

[0004]

In the above-mentioned conventional dust collector and filter, solid particles accumulate and need to be periodically cleaned, so that the analysis by the gas analyzer can be performed continuously. There was no problem.

An object of the present invention is to provide a gas analysis pretreatment device which enables continuous analysis by a gas analyzer.

Another object of the present invention is to provide a waste gasification and melting apparatus capable of continuous automatic operation for a long time.

[0007]

SUMMARY OF THE INVENTION A gas analysis pretreatment apparatus according to the present invention is provided upstream of a gas analyzer and removes solid particles in a gas to be analyzed. A pipe to flow down is provided vertically, and the gas to be analyzed is caused to flow through the pipe to purify the gas by gas-liquid contact.

[0008] Preferably, the pipe is a round pipe.

Preferably, a plurality of pipes are arranged.

This gas analysis pretreatment device is preferably provided in a waste gasification and melting device. Waste gasification and melting equipment pyrolyzes waste in a gasification furnace, guides the combustible gas generated to the melting furnace and burns it, melts the ash with the heat of combustion, and removes the heat of the exhaust gas from the melting furnace. A gas analyzer for continuously recovering the oxygen concentration in the gasification furnace is provided for recovering heat in a waste heat boiler, and the gas analysis pretreatment device is a gas analyzer and a gas analyzer. It is provided between them.

The waste gasification and melting apparatus is designed to automatically introduce boiler steam into the gasification furnace to reduce the oxygen concentration when the oxygen concentration in the gasification furnace increases. Is preferred. Further, the waste gasification / melting apparatus may be configured to automatically introduce an inert gas into the gasification furnace to decrease the oxygen concentration when the oxygen concentration in the gasification furnace increases. .

[0012]

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

FIG. 1 shows an embodiment in which the gas analysis pretreatment apparatus of the present invention is used in a fluidized bed gasification and melting apparatus.

A fluidized bed gasification and melting apparatus (1) is a fluidized bed gasification furnace (2) for thermally decomposing waste such as municipal solid waste and industrial waste.
And a melting furnace (3) that burns the combustible gas generated in the gasifier (2) and melts the ash with the combustion heat, and a waste heat boiler (4) that recovers the heat of the exhaust gas from the melting furnace (3). ).

The waste introduced into the gasifier (2) by the dust supply device (5) is thermally decomposed by the heat of the medium of the fluidized bed (6) and the heat of partial combustion, and combustible gas, char, Tar, dust, etc. are generated. These are the gasifier outlet (7)
And discharged into the melting furnace (3). In the melting furnace (3), the pyrolysis gas and the char burn, and the heat of combustion melts dust and ash. Exhaust gas from the melting furnace (3) is led to a boiler (4), which gives heat to generate steam and is discharged through a bag filter (8).

In the gasification furnace (2), if the pressure inside the furnace (2) becomes positive, harmful gases such as CO gas may be blown out. It is kept at pressure. The pressure inside the furnace (2) fluctuates due to fluctuations in the properties of waste and fluctuations in the supply amount, and may be even lower than normal operating pressure. At this time, the atmosphere is sucked into the furnace (2), the oxygen concentration in the furnace (2) rises,
(2) An internal explosion may occur.

Therefore, the fluidized bed gasification and melting apparatus (1) includes:
The oxygen concentration in the furnace (2) gas is monitored, and when the oxygen concentration rises,
An explosion prevention device (9) is provided to blow inert gas into the generated gas below the explosion limit.

The explosion prevention device (9) includes a gas analyzer (10) for extracting gas in the flue at the outlet of the gasifier (2) with a sampling probe (11) and measuring the oxygen concentration, and a gas analyzer (10). Gas analysis pretreatment device (12) provided upstream of (10)
And a steam pipe (13) for introducing steam from the waste heat boiler (4) into the gasification furnace (2), and an automatic valve provided in the middle of the steam pipe (13).
(14) and a valve controller (15) provided between the gas analyzer (10) and the automatic valve (14) and configured to open the automatic valve (14) when the oxygen concentration increases. Have.

When an increase in the oxygen concentration is detected by the gas analyzer (10), the valve controller (15) receiving the detection signal causes the automatic valve to operate.
Send a valve control signal to (14) and open it, waste heat boiler (4)
Steam is introduced into the gasifier (2).

The sampling probe (11) has a built-in temperature control heater (16) as shown in FIG. The gas temperature and gas flow rate in the furnace (2) fluctuate, and as the gas temperature decreases, the probe (11) cools down, and tar and dust contained in the gas may condense and accumulate. By heating the probe (11) by the heater (16), the gas passage in the probe (11) is prevented from being blocked by tar or dust.

FIG. 3 shows a flow of the gas analysis pretreatment device (12), and FIG. 4 shows an embodiment of the gas analysis pretreatment device (12). 3 and 4, solid arrows indicate gas passages,
Dashed arrows indicate water passages.

The gas analysis pretreatment device (12) is composed of four stages (A to D) as shown in FIG.

The first stage A includes a sampling probe (11),
Wet wall upper pot (21), wet wall (22) and circulating fluid tank (23)
It has. By contacting the sample gas (analyte gas) with the flowing water on the wetting wall (22), solid particles in the sample gas move to the flowing water. The first stage A cools the pyrolysis gas and condenses the tar to separate it from the gas.

The second stage B includes a wet wall upper pot (24), a wet wall (25), a gas scrubber (26), and a circulating liquid tank (27). The gas washer (26) uses an ejector or aspirator to increase the gas flow rate to increase the cleaning effect.
As the gas flow rate increases, the mixing of the gas with the circulating water and the collision of tar and dust are promoted, and more tar and dust are removed from the pyrolysis gas. The removed tar and dust are collected at the bottom of the circulating liquid tank (27).

The third stage C has a wet wall upper pot (28), a wet wall (29), a gas scrubber (30) and a circulating fluid tank (31), and has the same function as the second stage B. doing.

The fourth stage D includes a wet wall upper pot (32), a wet wall (33), a circulating liquid tank (34), a drain pot (35), a cassette type filter (36), an electronic cooler (37) and Equipped with a flow meter (38) to completely remove tar and dust, and to separate moisture in the gas.

In the gas analysis pretreatment device (12) shown in FIG. 4, the portion (A) for performing the processing of the first stage A in order from the left, the second
The part (B) that performs the processing of the stage B, the part that performs the processing of the third stage C
(C) and a part (D) for performing the processing of the fourth stage D. Each part (A) (B) (C) (D) is an upper pot (21) (24) (28) (32) serving as a sample gas and water inlet, respectively.
Wetting walls (2) are provided in a hanging manner on the upper pots (21), (24), (28), (32) and made to contact the analyte gas with the falling water.
2) (25) (29) (33), and a circulation tank (23) (27) (31) (34) in which water flowing down the wetting wall (22) (25) (29) (33) is stored. Circulation tank (23)
(27) (31) (34) Drain water from the bottom and draw the upper pot (21) (2
4) Circulating pumps (39), (40), (42) and (44) for returning to (28) and (32). Part (B) for performing the processing of the second stage B and third stage C
The part (C) for performing the above treatment further comprises a pot with an aspirator (26) (30) provided in the middle of the wetting wall (25) (29) and forcibly sending the sample gas and water downward, and a circulation tank ( 27)
(31) Withdraw water from the bottom and use a pot with an aspirator (2
6) A circulation pump (41) (43) for returning to (30).

In the part (A) where the processing of the first stage A is performed, the sample gas extracted from the sampling probe (11) not shown is introduced into the upper pot (21) and passes through the wetting wall (22). Sent down. The contact between the flowing water and the sample gas on the wetting wall (22) causes the solid particles in the sample gas to move to the flowing water. The sample gas is withdrawn from the top of the first circulation tank (23), introduced into the upper pot (24) of the part (B) to be treated in the second stage B, and passed downward through the wetting wall (25). Sent. In this part (B), the gas and water are forced downward by the aspirator pot (26), and the mixing of gas and circulating water is promoted.
It is designed to enhance the effect of removing solid particles. The sample gas is then withdrawn from the top of the second circulation tank (27), and the upper pot 2 of the part (C) where the third stage C treatment is performed
8), and the same processing as the processing of the second stage B is performed while passing through the wetting wall (25). The sample gas is further supplied to the third circulation tank
(34) is extracted from the top, reaches the upper pot (32) of the part (D) where the processing of the fourth stage D is performed, and is the same as the processing of the first stage A while passing through the wetting wall (33). Is given. The sample gas from which solid particles such as tar, dust, and char have been completely removed through the four-stage treatment is supplied to a cassette type filter (not shown).
(36), and sent to the gas analyzer (10) via the electronic cooler (37).

In the embodiment shown in FIG. 4, each wetting wall (2
2) (25) (29) (33) is formed by a vertically provided round pipe, water flows down along the inner wall surface of the pipe,
The sample gas is made to pass downward through the inside of the pipe. If there is a portion where water does not flow, water flows over the entire inner wall surface of the pipe because dust adheres and accumulates on the wall surface. The pipe may be a round pipe or a square pipe. The lower end of each wetting wall (22) (25) (29) (33), so that dust does not accumulate here, each circulation tank (23) (27) (31) (34)
Above the liquid level. Each circulation tank (23)
(27) (31) (34), vertical partition wall (23a) (27a) (31a) (34a), the water flowing down each wet wall (22) (25) (29) (33) falls It is divided into two parts, a part and a part from which water is extracted by a circulation pump, so that dust and the like do not enter the circulating water. In the second stage B and the third stage C, the bottoms of the circulation tanks (23), (27), (31), and (34) are connected by communication pipes (45), (46), (47), respectively. And the second
-The tar, dust and char accumulated in the fourth circulation tank (27) (31) (34) are collected at the bottom of the first circulation tank (23) by these communicating pipes (45) (46) (47). Then, it is sucked by the circulation pump (35) of the first circulation tank (23) and discharged out of the system.

According to the gas analysis pretreatment device (12), since solid particles are continuously removed from the gas to be analyzed by using circulating water, the frequency of cleaning the device (12) can be extremely low. The analysis by the gas analyzer (10) can be performed continuously. Therefore, when a dust collector or a filter is used, the continuous analysis time, which is several hours to several tens hours, is extended to several tens hours to several hundred hours. When an increase in oxygen concentration is detected by the gas analyzer (10), the valve controller
(15) opens the automatic valve (14), the steam from the waste heat boiler (4) is introduced into the gasifier (2), and the oxygen concentration in the furnace (2) is always kept below the explosion limit . This makes it possible to automatically and continuously operate the fluidized bed gasification and melting apparatus (1) for a long time.

In the above description, the first to fourth stages are performed. However, the number of stages is not limited to four, and the number of stages may be increased or decreased according to the properties of gas or the degree of removal of solid particles. Is of course possible. The steam from the waste heat boiler (4) is introduced into the gasification furnace (2) .However, an inert gas such as nitrogen gas is introduced into the gasification furnace (2) and the furnace ( 2) The oxygen concentration in the inside may be reduced.

[0032]

According to the pretreatment apparatus for gas analysis of the present invention, the solid particles move into the flowing water by the contact between the gas to be analyzed and the falling water, and the solid particles in the gas to be analyzed are removed. Therefore, cleaning of the accumulated solid particles, which is required when a dust collector or a filter is used, becomes unnecessary, and the analysis by the gas analyzer can be continuously performed.

Further, by providing this gas analysis pretreatment device in a waste gasification and melting device, a fluidized bed gasification and melting device can be operated continuously for a long time.

Further, when the oxygen concentration in the gasification furnace rises, the oxygen concentration in the furnace always explodes by introducing an inert gas or steam from a boiler into the gasification furnace to lower the oxygen concentration. It is kept below the limit, and automatic continuous operation of the gasification and melting apparatus becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a fluidized bed gasification and melting apparatus in which a gas analysis pretreatment apparatus according to the present invention is used.

FIG. 2 is an enlarged view of a sampling probe.

FIG. 3 is a flowchart of a gas analysis pretreatment device.

FIG. 4 is a diagram schematically showing a specific example of a gas analysis pretreatment device.

[Explanation of symbols]

 (1) Waste gasification and melting equipment (2) Fluidized bed gasifier (3) Melting furnace (10) Gas analyzer (12) Gas analysis pretreatment equipment (22) (25) (29) (33) Wet wall

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Matsumori 5-3-28 Nishikujo, Konohana-ku, Osaka-shi Inside Hitachi Zosen Corporation (72) Inventor Hiroyuki Domoto 5-3-28 Nishikujo, Konohana-ku, Osaka-shi Hitachi Zosen Corporation

Claims (6)

[Claims] 1. A gas analysis pretreatment device provided in front of a gas analyzer for removing solid particles in a gas to be analyzed, wherein a pipe for flowing down a cleaning water for the gas to be analyzed is provided vertically, A gas analysis pretreatment device configured to flow a gas to be analyzed through a pipe and purify the gas by gas-liquid contact. 2. The gas analysis pretreatment apparatus according to claim 1, wherein the pipe is a round pipe. 3. The gas analysis pretreatment apparatus according to claim 1, wherein a plurality of pipes are arranged. 4. A waste gas is pyrolyzed in a gasification furnace, the combustible gas generated is guided to a melting furnace and burned, the ash is melted by the combustion heat, and the heat of the exhaust gas from the melting furnace is converted into a waste heat boiler. 2. A waste gasification and melting apparatus for recovering heat by using a gas analyzer for continuously analyzing an oxygen concentration in a gasification furnace, wherein a gas analyzer is provided between the gasification furnace and the gas analyzer. A waste gasification / melting device, comprising the gas analysis pretreatment device according to any one of claims 1 to 3. 5. The waste gas according to claim 4, wherein the boiler steam is automatically introduced into the gasification furnace to decrease the oxygen concentration when the oxygen concentration in the gasification furnace increases. Chemical melting equipment. 6. The waste gas according to claim 4, wherein an inert gas is automatically introduced into the gasification furnace to decrease the oxygen concentration when the oxygen concentration in the gasification furnace increases. Chemical melting equipment.