JPH09262422A - Dust collector for hot gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge dust falling to a hopper space without delay by making a gas introducing part communicate with a hopper space, forming a diffuser expanding downward on the outer periphery of the upper end of a communicating pipe 13, and returning dust containing gas to the introducing part from the hopper space. SOLUTION: A communicating pipe 13 arranged almost vertically in the center part of a vessel 2 for making a dust containing gas introducing pipe 10 communicate with a hopper space 7 by openings 'p' provided on its both ends is provided. And a diffuser 8 is formed between a pipe 15 of the gas introducing part 10 and an upper end part 13e of the communicating pipe 13. An opening is arranged on the upper end side face of the communicating pipe 13 and in a throat part of narrow flow passage area of the diffuser 8. By the difference in static pressure of the dust containing gas between the throat part of the diffuser and an outlet thereof, the dust containing gas in the hopper space 7 is returned to the gas introducing part 10 through the communicating pipe 13. Therefore, dust in the hopper space 7 is discharged without delay.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic filter suitable for dust removal of high temperature dust-containing gas discharged in a combustion process such as a power plant using a pressurized fluidized bed boiler, a direct coal combustion apparatus, or a coal gasification plant. The present invention relates to a dust remover for high temperature gas.

[0002]

2. Description of the Related Art The technology related to a high-temperature gas dust removal device incorporating a ceramic filter is intended to realize a coal gasification plant or a power generation plant using a pressurized fluidized-bed boiler, which is a next-generation high-efficiency and clean coal utilization technology. It is regarded as a key technology of the world, and development for practical use is progressing in various countries around the world.

When the dust remover is used by incorporating it into these plants, the behavior of dust at high temperatures is of particular concern. That is, generally, the higher the temperature is, the larger the viscosity coefficient of gas is, and the dust is strongly influenced by the gas flow at high temperature, and the main dust-containing gas in the dust removing chamber (the part where solid-gas separation is performed in the dust removing device) is Even if the flow is designed to be generally downward, a part of the fine dust tends to ride against the turbulent gas flow and flow against gravity, and does not easily fall into the hopper.

In an actual plant, the flow in the dust removal chamber constantly changes due to the turbulence caused by the operating conditions of the dust removal device itself or the disturbance generated in the upstream system or the downstream system, and a turbulent flow accompanied by various sidestreams is generated in the dust removal device. It exists inside.

As a result, the dust removing device has the following problems. This is a phenomenon seen in so-called candle type dust removers that use filter tubes with one end closed, and cross flow type dust removers that use plate filters.Backwashing ceramic filters by sideways or upward flow. Even if the dust does not fall into the lower hopper space, it is deposited again on the nearby ceramic filter, and because this is repeated, dust is thickly deposited on the surface of some ceramic filters, and finally the dust-containing gas side of the ceramic filter. Part of the flow path is blocked with accumulated dust.

When such dust bridging occurs,
When the effective filtration area of the ceramics filter is gradually reduced and the processing capacity of the dust remover is reduced, the unburned components contained in the bridged dust are often ignited when removing the combustion gas from the pressurized fluidized bed boiler. Combustion causes the ceramic filter to be fatally damaged by thermal stress caused by combustion heat.

Further, in the dust removal treatment of the gas produced in the coal gasification plant, the oxygen-containing air is removed when the state replaced with the non-oxidizing gas immediately after the operation is stopped is changed to the air atmosphere or when the operation is restarted. When existing in the apparatus, unburned components contained in the bridging dust and the like ignite and burn, causing fatal heat damage to the ceramic filter of the dust removing apparatus.

Further, when the load on the plant changes, a large amount of unburned components such as combustible gas and soot are discharged into the combustion gas and fly to the ceramics filter, which then ignites and abnormally burns. For example, when removing combustion gas from a pressurized fluidized bed boiler, a large amount of unburned components are generated depending on the operation of the boiler at low load, even though the oxygen concentration in the system is high, and a large amount of dust is contained in the dust. Flammable gas containing more than 10,000 ppm of carbon monoxide may be generated together with soot (sometimes reaching 30%).

In a pressurized fluidized bed boiler, a method is generally adopted in which combustion gas roughly dust-removed by a cyclone is removed by a dust-removing device having a built-in ceramic filter.
The cyclone does not exhibit a sufficient dust removal function due to dust overflow in a transient state where the dust concentration in the dust-containing gas rapidly increases.

In this case, the dust-containing gas containing a large amount of unburned components passing through the cyclone reaches the ceramic filter of the dust removing device. Since the dust concentration in the dust-containing gas at this time is 5 to 10 times the dust concentration in the steady state, the increase gradient of the filtration differential pressure is also 5 to 10 times that in the steady state.

In a candle-type dust removing device using a filter tube with one end closed, since the flow passage cross-sectional area on the dust-containing gas side of the dust removing chamber is large, the flow of dust-containing gas in the dust removing chamber is made completely downward. This is difficult, and dust tends to accumulate in a large amount on some filter tubes, and when dust or the like contains a large amount of unburned components, there is a high possibility of ignition and combustion.

A ceramic filter uses a filter tube with both ends open, the inside of the apparatus container is partitioned by a plurality of horizontal tube plates, and both ends of the plurality of filter tubes are held by the upper and lower tube plates, respectively, and dust-containing gas is prevented. A dust remover (hereinafter referred to as a tube type dust remover) configured to flow downward inside a filter tube is disclosed in Japanese Examined Patent Publication No. 63-40567 and Japanese Examined Patent Publication 2-2.
2689, Japanese Patent Publication No. 3-24251, Japanese Patent Publication No. 3-6107
6 and the like. Since the cross-sectional area of the flow path on the dust-containing gas side is small in the tube-type dust remover, it is easy to make the flow on the dust-containing gas side completely downward.

Therefore, under normal operating conditions, the dust does not deposit thickly on the filtration surface of the filter tube, the absolute amount of the unburned components that fly in does not fluctuate significantly, and there is always 10 particles in the dust.
% Of unburned components are contained, and as long as the unburned components are constantly and gradually burned on the surface of the filter tube, there is no problem of heat damage to the filter tube.

However, even in the tube type dust remover,
When the dust-containing gas containing a large amount of unburned components is introduced, a large amount of dust is accumulated on the inner surface of the lower end portion of the filter tube where the downward gas flow velocity is close to zero. The accumulated dust ignites and burns all at once, causing the temperature inside the filter tube to rise rapidly, the temperature difference between the inside and outside of the filter tube exceeding the allowable temperature difference of the ceramics, and the filter tube is damaged by thermal stress.

The flow velocity at the lower end of the filter tube is affected by the distribution of pressure and velocity in the gas inlet chamber of the apparatus, and the flow rate of the dust-containing gas varies among the filter tubes. For example, it became clear that there is a filter tube in which dust-containing gas flows back from the hopper space.

Further, the distribution of the pressure and velocity of the dust-containing gas in the gas inlet chamber is influenced by the fluctuations in the upstream of the plant regardless of whether the tube type dust removing device or the candle type dust removing device is used, and this changes every moment. It was also found to be one of the causes of the turbulent gas flow in the space.

The present inventors previously provided a diffuser in the dust-containing gas introducing portion of the container or the dust-containing gas introducing pipe, and provided a throat portion of the diffuser having a static pressure lower than that of the hopper space and a hopper space having a high static pressure. A communicating pipe is provided to communicate the dust-containing gas in the hopper space to the dust-containing gas introduction part by the difference in static pressure between the openings at both ends of the communicating pipe, and a downward flow of a constant flow velocity is provided at the lower end of the filter pipe. The configuration shown in FIG. 8 to be generated was proposed in Japanese Patent Laid-Open No. 6-47226.

This proposal is a useful method for suppressing the ignition and combustion of unburned components in a tube type dust remover, a candle type dust remover, or another ceramic filter device, and its usefulness has already been confirmed in a tube type dust remover. Was given.

However, in all of the dust removers disclosed in Japanese Patent Laid-Open No. 6-47226, the following problems are found because the end of the communicating pipe is connected to the side surface of the diffuser throat. It was a. In the tube type dust remover in which the inlet of the dust-containing gas is located in the upper center part of the container or the dust remover shown in US Pat. No. 5,348,572, the dust-containing gas is distributed relatively evenly and along the filtration surface of the ceramic filter. Since it easily flows down, the invention of JP-A-6-47226 can be preferably applied. But,
The diameter of the diffuser outlet is not so large compared to the diameter of the dust removal chamber inlet, so the distance between the diffuser outlet and the dust removal chamber inlet (upper end of the dust removal chamber) should be large so that all filter tubes contain dust evenly. The gas needs to be distributed. For this purpose, it is necessary to increase the height of the container by this amount, which increases the weight of the container. b. Since the dust-containing gas flows at a considerable speed in the communication pipe, wear occurs due to the dust-containing gas at the bent portion of the communication pipe. c. In the case of the tube type dust remover, since the communication tube is held at both ends by the tube sheet and the throat of the diffuser, considerable thermal stress is generated during operation. d. The bent pipe in the gas inlet chamber, the dust removing chamber, or the hopper space disturbs the flow of the dust-containing gas, making it difficult to evenly distribute the dust-containing gas to the filter tubes. e. In the case of the large-tube-type dust remover having the configuration shown in FIG. 8 shown in JP-A-6-47226, if the circulating gas amount is increased in consideration of the evenness of the downward flow in each filter tube and the wear of the communication tube, the communication becomes difficult. It is necessary to increase the number of pipes 13, which is troublesome in inspection, assembly, disassembly and maintenance inspection. By arranging a plurality of communication pipes, the introduced dust-containing gas can be evenly distributed to each filter pipe macroscopically, but since many communication pipes cross the dust-containing gas flow in the gas inlet chamber,
A Karman vortex is inevitably generated in the lower part of the communication tube, which may resonate with other vibrating elements, impairing the reliability of the device. f. In the case of the dust remover shown in FIG. 8, the descending flow velocity of the dust-containing gas in the filter pipe in the peripheral portion is smaller than the descending flow velocity in the filter pipe in the central portion, so that a part of the communication pipe is arranged in the peripheral portion. When arranged, the gas flow in each filter tube can be equalized, but a gas flow in the direction indicated by the arrow is generated in the hopper space, which hinders the movement of dust that has fallen onto the inner wall of the hopper.

[0020]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to eliminate the exhaust gas from a high temperature pressurized combustion process such as a pressurized fluidized bed boiler or a coal gasification plant. A communication pipe that recirculates dust-containing gas, which is suitable for dust removal, and the structure of its support are simple and highly reliable, and dust can be discharged smoothly from the hopper space to the gas inlet. To provide a dust remover for high temperature gas, which is provided with a means.

[0021]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and a high temperature gas dust removing apparatus of the present invention has a ceramics filter and a dust-containing gas introducing portion at an upper portion thereof. A dust remover having a container having a hopper space for collecting dust in the lower part and a backwashing means for regenerating a ceramics filter, which is arranged substantially vertically in the center of the container and provided at both ends thereof. Having a communication pipe that communicates the dust-containing gas introduction part and the hopper space by the opening, a diffuser is formed between the cylinder provided in the gas introduction part and the upper end of the communication pipe, and the upper end of the communication pipe is The opening provided on the side surface is located in the throat of the diffuser having a narrow flow passage cross-sectional area, and the dust-containing gas in the hopper space creates a communication pipe due to the static pressure difference between the dust-containing gas at the throat of the diffuser and the outlet of the diffuser. Characterized in that it is recirculated to the gas inlet portion Te.

In the dust remover of the present invention, the diffuser is formed between the inside of the cylinder provided in the gas introduction part and the upper end of the communication pipe, and the diffuser with the lowest static pressure in the dust-containing gas side space inside the container is used. The inlet part or the throat part of the diffuser (the part with the narrowest flow passage cross-sectional area) and the hopper space are connected by a communication pipe, and the dust-containing gas is introduced from the inside of the hopper space through the communication pipe to the side surface of the communication pipe provided in this throat part. The structure is such that it is sucked into the diffuser from the opening and is refluxed.

Specifically, for example, the upper end portion of the communication pipe is formed into a paraboloid of revolution, a spherical shape or a conical shape which is convex toward the upstream side of the dust-containing gas flow, and a slit shape is formed on the side surface near the upper end portion of the communication pipe. Alternatively, an opening including a plurality of holes is provided. The inside of the cylinder provided in the gas introduction part is expanded toward the downstream side to form a diffuser. It is preferable to use one communication pipe, but in the case of a device having a plurality of gas introduction ports, a communication pipe may be provided for each gas introduction port, and a plurality of communication pipes may be provided in one dust removing device. . Moreover, you may make it branched in the part which passes through the dust removal chamber of one communicating pipe, or in a hopper space.

Here, the diffuser refers to a diffuser having a function of converting the kinetic energy of the gas into static pressure, which has a cross-sectional area of the gas passage expanded toward the downstream side.

In order to prevent ignition and combustion of unburned components in the dust removal chamber of the dust removal apparatus for high temperature dust-containing gas, it is preferable that the descending flow velocity of the dust-containing gas at the lower end of the filter tube is 2 m / s or more.

According to the experience of the present inventors in the apparatus for removing the combustion gas from the pressurized fluidized bed boiler, if the descending flow velocity at the lower end of the filter tube is less than 2 m / s, if it is 0.5 m / s or more, ignition combustion Has the effect of suppressing If the flow velocity is less than this, the effect of suppressing ignition and combustion cannot be expected, but it has the effect of equalizing the gas flow distribution in the dust removal chamber. In dust removal of combustion gas from the pressurized fluidized bed boiler, if the descending flow velocity at the lower end of the filter tube is set to 3.5 to 5 m / sec, it is possible to more reliably prevent ignition and combustion of unburned components in the dust.

In the preferred high temperature gas dust remover of the present invention, the gas introducing portion is provided at the center of the upper part of the container, and one connecting pipe is provided substantially vertically from the central portion of the hopper space to the gas introducing portion.

In the preferred high temperature gas dust remover of the present invention, the ceramics filter is a filter tube having both ends open, and the inside of the container has a dust removal chamber partitioned by horizontal tube plates, and is arranged substantially vertically. The upper and lower ends of the installed filter tubes are held by the upper and lower tube plates, and the dust-containing gas is configured to flow inside each filter tube.

In the tube type dust remover, since the flow path of the dust-containing gas in the dust removing chamber is inside the filter tube, the cross-sectional area of the flow path of the dust-containing gas is small and a relatively small amount of dust-containing gas is discharged from the hopper space. If the gas is recirculated to the inlet chamber or its upstream, a large amount of dust is accumulated on a part of the filter surface when dust-containing gas containing a large amount of dust is introduced into the dust remover, or the dust-containing gas flow passage is blocked by the dust. Even if a large amount of dust containing unburned components is introduced into the dust remover, it is possible to avoid the problem that the unburned components ignite and burn near the surface of the filter tube and cause thermal damage to the filter tube. it can.

In the preferred high temperature gas dust remover of the present invention, the communication pipe is formed by connecting a plurality of communication pipe portions in the vertical direction, and each of the communication pipes can be drawn upward from the container. The part is attached.

In a large-sized tube type dust remover, if one communication pipe is used and the diameter of the communication pipe is set to about 500 to 600 mm, if the communication pipe is pulled out, the operator can utilize the space with the communication pipe from above. You can get down to any dust chamber,
Work such as maintenance becomes easy.

In the preferred high temperature gas dust removing apparatus of the present invention, four or more dust removing chambers having the same volume are provided in the container vertically, and two or more dust removing chambers adjacent to each other with the tube sheet in the container sandwiched therebetween. A working space having a height substantially equal to that of each dust removing chamber is provided between the groups.

The working space has a height such that an operator can enter the device when the apparatus is stopped to perform internal inspection and other works, and preferably has a length equal to or longer than the length of the filter tube at each stage. With this height, the filter space below the gas inlet chamber and the working space can be removed and installed at the same time by using the central space where the working space and the communication pipe were located. The time required for the replacement etc. can be greatly reduced.

In another preferred high temperature gas dust remover of the present invention, the ceramics filter is a filter tube with one end closed, and a dust removal unit in which a plurality of filter tubes are attached substantially vertically to the lower side or the upper side of the clean gas header is provided. The dust-containing gas is disposed in the container and is configured to remove dust while sequentially descending from the top of the dust removal unit.

When the dust remover for high temperature gas is a candle type dust remover in which such a dust remover is provided in a container, the flow passage cross-sectional area of the dust-containing gas in the dust remover is large. In order to avoid the uneven accumulation of dust on the surface of part of the filter tube, it is necessary to recirculate a large amount of dust-containing gas from the hopper space to the dust-containing gas introduction portion.

In the preferred high temperature gas dust remover of the present invention, the dust-containing gas in the hopper space is recirculated to the gas introducing portion through one substantially vertical communication pipe having an opening at the center of the hopper space. This simplifies the arrangement and support structure of the communication pipe, and the communication pipe can be arranged so as not to be restricted by thermal expansion, so that no excessive stress is generated in the communication pipe. Therefore, the reliability of the communication pipe is increased, and the rising dust-containing gas flow does not occur in the peripheral portion of the hopper space, so that the dust dropped on the inclined surface of the hopper moves to the lower discharge port without interruption.

In another preferred high temperature gas dust remover of the present invention, an ejector or an injector for promoting the inflow of dust-containing gas into the communication pipe is attached to the opening of the communication pipe provided in the hopper space.

According to this structure, when the combustion gas of the pressurized fluidized bed boiler is removed, when the boiler for co-firing coal and light oil starts up or when the load is low, the amount of unburned components coming in increases. The reflux rate can be increased independently of the inflowing dust-containing gas flow rate, and at the time of start-up, low load, or fuel purging inside the boiler following a fuel trip,
The circulation rate of dust-containing gas can be increased freely with the help of an ejector or an injector that uses high-pressure gas. By adopting this configuration, it is possible to reduce the amount of circulating gas under high load where ignition and combustion are less likely to occur in the dust removal chamber.

In another preferred high temperature gas dust remover of the present invention, a swirling means for forcibly swirling the dust-containing gas in the hopper space is provided. As the swirling means, high-pressure gas is blown into the hopper space from a nozzle directed substantially tangentially to the inner wall of the container, or a deflection plate is attached to the lower end of the filter tube, and the dust-containing gas stream flowing out of the filter tube is deflected. It is a preferable method to apply a swirling force to the dust-containing gas in the hopper space by hitting it. When the dust-containing gas swirls in the hopper space, the cyclone effect hardly sucks dust that has fallen into the hopper space from the opening of the communication pipe.

The communication pipe for circulating the dust-containing gas from the hopper space to the dust-containing gas introduction portion of the dust remover can be shortened by providing it inside the pressure vessel, and the energy loss spent for the circulation of the dust-containing gas can be reduced. Further, it is not necessary to apply a heat insulating material on the outer periphery of the communication pipe, there is no energy loss due to heat dissipation from the surface of the communication pipe, and it is not necessary to use pressure resistant piping for the communication pipe, so the construction cost of the device can be saved. .

In another preferred high temperature gas dust remover of the present invention, the dust-containing gas is the combustion gas of a pressurized fluidized bed boiler.
In other words, it is particularly suitable for a power plant incorporating a pressurized fluidized bed boiler, which is a future energy technology that uses coal with high efficiency and is clean (a small amount of SOx and NOx are emitted.). In this type of power plant, it is possible to obtain high power generation efficiency by using a steam turbine with steam of a boiler and a gas turbine driven by combustion gas, and the dust remover burns in a pressurized state. It is used to remove dust in the combustion gas that is harmful when the gas is used to drive the gas turbine (wears the blades of the gas turbine and shortens its life).

The high-temperature gas dust remover of the present invention is preferably applied to dust removal when a high-temperature dust-containing gas containing a large amount of unburned components is temporarily generated, for example, when the load of a pressurized fluidized bed boiler is increased or decreased. By preventing large amounts of dust containing unburned components from accumulating on the surface of the ceramic filter, the ignition of unburned components in the accumulated dust is suppressed, and even if it is ignited and burned, the built-in ceramic filter can be fatal. Thermal damage can be avoided.

[0043]

EXAMPLES The high-temperature gas dust remover of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

FIG. 1 is a vertical sectional view showing an embodiment in which the present invention is applied to a tube type dust remover. FIG. 2 shows A in FIG.
FIG. 5 is an enlarged view of part B, and FIG. 5 is an enlarged view of part B in FIG. Figure 1,
2 and 5, 1 is a tube type dust remover, 2 is a pressure vessel, 3 is a filter tube, 5a, 5b, 5
c, 5d, 5e, and 5f are tube plates (5a, 5a, 5a, 5a, 5f that support the respective filter tubes and horizontally partition the interior of the pressure vessel).
c, 5d, and 5f partition the space between the dust-containing gas and the dust removal chamber, and the other tube plates partition the dust removal chamber. ), 6 is a gas inlet chamber for uniformly distributing the introduced dust-containing gas to each filter tube,
7 is a hopper space, 8 is a diffuser formed between the cylinder 15 provided in the gas introduction portion and the outer periphery of the communication pipe portion 13e,
Reference numerals 9a, 9b, 9c, and 9d denote first, second, third, and fourth dust removal chambers, 25 is a working space, and 10 is a gas inlet. A heat insulating material is lined inside the pressure vessel 2.

Reference numerals 11a, 11b, 11c and 11d denote clean gas outlet pipes 12 also functioning as diffusers of ejectors for blowing backwash gas into the first, second, third and fourth dust removing chambers, respectively. Is a clean gas outlet, 13e, 13a, 13
Reference numerals b, 13s, 13c, 13d, and 13h are heat-resistant metal communication pipe portions that constitute the communication pipe 13 that recirculates the dust-containing gas from the hopper space to the gas introduction portion. 14a, 14b,
14c and 14d are ejector nozzles for ejecting compressed air for backwashing to the respective clean gas outlet pipes, 13n are openings (suction ports) at the tips of the communication pipe portions 13h of the hopper, and 13m.
Is a slit-shaped opening (suction port) of the communication pipe portion 13e arranged in the throat of the diffuser 8 formed between the cylinder 15 provided in the gas introduction portion and the outer periphery of the upper end of the communication pipe. 5 is an enlarged cross-sectional view of the communication pipe 13 of FIG.
17a, 17b, 17c of the communication pipe portions 13e, 13
Bellows connecting a, 13b, and 13s, 18 is a heat insulating material that protects the bellows from heat of hot gas, and 19 is a liner that closes the inner recess of the communication pipe and protects the heat insulating material 18 from a high-velocity gas flow. .

If the communication pipe 13 is constructed as shown in FIG. 6, for example, the communication pipe portions 13e, 13a, 13b and 13s can be pulled out in this order at the time of open inspection of the tube type dust remover. A worker can enter the dust removing chambers 9a from the gas inlet chamber or the working space by using the space from which the communication pipe is removed, so that the filter pipe can be easily inspected. Here, the communication pipe portion 13e in the gas inlet chamber is attached to the tube plate 5a, and the communication pipe portion 13s in the working space is attached to the tube plate 5d. There is a bellows 17a at the upper end of the communicating pipe portion 13a in the first-stage dust removal chamber, and a lower end of 13a is a removable bayonet joint having a spherical surface, and a flange attached to the pipe plate 5b of the next stage. If it is mounted on the taper surface, the dust-containing gas will not leak to the adjacent dust removing chamber 9b. In order to protect the spherical surfaces of the bellows and the joint from the high heat of the dust-containing gas, a heat insulating material 18 and a heat insulating material protecting sleeve 19 are arranged on the outer periphery of the flow path of the dust containing gas, and the bellows and the spherical surface are surrounding the cooling tube plate. 5a, 5b, 5c,
It is radiatively cooled by 5d. Hereinafter, the second-stage dust removal chamber 9b, the third-stage dust removal chamber 9c, and the fourth-stage dust removal chamber 9d are similarly configured. Here, the communication pipe portion 1 in the hopper space
A bellows is not required in the upper part of 3h, and a bayonet joint for mounting the communicating pipe portion 13d in the fourth-stage dust removing chamber 9d is provided on the lowermost tube plate 5f. If the outer diameter of the lower bayonet joint is made smaller than that of the upper one, it is possible to pull out the communicating pipe portions arranged below two chambers or more when the device is opened. It should be noted that the communication pipe part in the dust removal chamber is a plurality of filter pipes or heat-resistant metal pipes having substantially the same outer diameter as the filter pipe, and the communication pipe part in the gas inlet chamber or in the gas inlet chamber and the hopper space is one heat-resistant metal pipe. It is also possible to do so. In this way, the worker cannot get down from the hole of the communication pipe, but the reliability of the device is improved because the large diameter bellows is not used. In this case,
Manholes through which workers enter and leave may be provided on the side walls of the dust removing chambers 9a, 9b, 9c, and 9d.

In the dust remover of FIG. 1, when the pressurized fluidized bed boiler needs to be partially loaded to ensure a high circulation rate of the gas containing dust, the opening 13m is located at the throat of the diffuser 8 shown in FIG.
-X, the throat portion of the diffuser 8 is Y-Y due to thermal expansion of the communication tube portion 13e attached to the tube sheet 5a and the tube 15 of the gas introduction portion fixed to the gas introduction port 10 under high load.
Go to That is, when the throat of the diffuser moves from XX to YY, as shown in FIG.
With -Y, since the cross-sectional area of the flow passage is larger than that of the flow passage of YY, the circulation rate at high load can be made smaller than that at partial load. The dust-containing gas flows in from the gas inlet 10 in the direction of the arrow, reaches the upper end 13t of the communication pipe 13 and is accelerated, and has a maximum flow velocity at the throat of XX during partial load and YY during high load. , The static pressure becomes the minimum. Since the flow passage cross-sectional area of the gas in the diffuser 8 gradually increases from the throat, the dust-containing gas flow recovers the static pressure in the diffuser 8 and the static pressure is 1000 mmAq higher than the static pressure in the throat of the diffuser 8, for example. It flows into the gas inlet chamber 6. Since there is a pressure difference of about 200 mmAq between the gas inlet chamber 6 and the hopper space 7,
The dust-containing gas in the hopper space 7 recirculates to the gas introduction portion through the opening 13n, the communication pipe 13 and the opening 13m of the throat due to the differential pressure of about 800 mmAq.

FIG. 4 is a vertical sectional view showing another example of the structure of the gas introducing portion applied to the dust removing device of the present invention. FIG.
Then, the communication pipe 13 is inserted from the pocket 27p provided in the curved pipe 27 provided in the gas introduction port 10, and the upper end thereof is not exposed in the dust-containing gas flow. Although the cross-sectional area of the gas flow passage on the upstream side of the diffuser is gently narrowed near the throat, it may be rapidly narrowed if the pressure loss due to the diffuser may be slightly increased. In addition, 27a in FIG. 4 is a gas inlet.

In the high-temperature gas dust remover 1 of FIG. 1, the dust-containing gas distributed to each filter tube 3 in the gas inlet chamber 6 is filtered on the inner surface of the filter tube 3 while descending inside the filter tube 3. , Clean gas and dust removal chambers 9a, 9b, 9c, 9
It flows into the clean gas side space of d. Dust removal chambers 9a, 9b, 9
The clean gas flowing out of c and 9d is collected at the downstream of the clean gas outlet pipes 11a, 11b, 11c and 11d, respectively,
It is sent to the downstream system from the clean gas outlet 12.

The dust-containing gas flowing in the filter tube 3 exudes to the outside as it flows down in the filter tube 3, so that the downward flow velocity decreases downward and flows into the hopper space 7.

A part of the dust-containing gas that has flowed into the hopper space 7 descends a certain distance as it is, then reverses at the center of the hopper space 7 and is sucked into the opening 13n of the communication pipe 13.
The arrangement of the opening 13n is determined in consideration of the flow of the dust-containing gas in the hopper space 7.

When the opening 13n is provided in the central portion of the hopper space 7, the dust-containing gas flow in the hopper space 7 becomes symmetrical with respect to the central axis, and the dust-containing gas flow descends along the inclined surface of the hopper. Therefore, it is difficult for dust to accumulate on the inclined surface of the hopper.
Further, a deflecting plate is provided in the opening 13n at the lower end of the filter tube 3, and a swirling means for injecting high-pressure gas from a nozzle directed in the tangential direction of the container into the hopper space 7 is provided to swirl flow into the hopper space 7. The dust-containing gas in the hopper space 7 is swirled and a centrifugal force acts on the dust, so that the dust is hardly sucked from the opening 13n.

Diffuser effect causes diffuser 8
When a static pressure difference of 300 to 2000 mmAq is generated between the throat and the outlet of the device, the amount of dust-containing gas introduced into the dust remover 1 varies depending on the design of the tube type dust remover 1 and the plant to which it is applied. It is possible to recirculate 7 to 20% of the dust-containing gas, and thereby a downward flow velocity of the dust-containing gas that can suppress ignition and combustion can be secured at the lower ends of all the filter tubes 3.

When the introduction of the dust-containing gas into the dust remover 1 is started and dust begins to accumulate on the inner surface of the filter tube 3, the gas inlet chamber 6 and the clean gas outlet tubes 11a, 11b, 11c and 11d.
The pressure difference between the two, that is, the filtration pressure difference, gradually increases. The filtration pressure difference is usually backwashed at regular intervals to regenerate the filter, and a low filter pressure difference below a predetermined value is maintained.

For backwashing the filter tube 3, compressed air is ejected from the ejector nozzle 14 by opening and closing a control valve that operates at high speed.
a, 14b, 14c and 14d are alternately ejected, and the pressure in the clean gas side space of the corresponding dust removing chambers 9a, 9b, 9c, 9d is made higher than the pressure inside the filter tube 3 so that the gas of the filter tube 3 is discharged. Reverse flow from the outside to the inside and filter tube 3
Dust that has accumulated inside is separated from the inner wall surface of the filter tube 3, is pushed away by the downward gas flow in the filter tube 3, and is dropped into the hopper space 7.

Opening time of these control valves (fully closed to fully open,
The time required for full closing) is usually 0.1 to 0.5 seconds.
For effective backwashing, the time required from fully closed to fully opened and the holding time in the fully opened state are important. If the time required from full close to full open is too long, compressed air consumption will increase,
If the backwash differential pressure of the filter tube 3 does not become sufficiently large and the holding time of the fully open state is too short, the rise of the backwash differential pressure is insufficient and the regeneration of the filtering function of the filter tube 3 becomes incomplete.

If the backwash regeneration is incomplete, the filtration differential pressure of the filter tube 3 gradually increases, and the dust removal capability decreases. The conditions for backwashing are control valve type, size, compressed air pressure, compressed air pipe thickness, effective filtration surface area of the filter tube 3 for backwashing and dead volume outside the filter tube 3 (clean gas in the dust removal chamber). The optimum valve opening time is determined by the side space volume).

The backwashing may be performed at regular intervals (for example, 20 minutes) in the order of the dust removing chambers 9a, 9b, 9c, and 9d, and each dust removing chamber may be intermittently performed at intervals of 60 seconds or less. , 9
b, 9c, 9d dust chambers at regular intervals (for example, 5 minutes)
You may backwash each time. FIG. 6 is a vertical cross-sectional view showing an example of another preferable configuration of the communication pipe 13 of the dust removing device of the present invention. In the figure, 16a and 16b are holders with a bayonet joint. The same parts as those in FIG. 5 are designated by the same reference numerals as those in FIG. This bayonet joint is a bayonet joint that can be attached and detached by rotating the communicating pipe portions 13a and 13b by 45 °.

FIG. 7 is a vertical sectional view showing another preferred embodiment of the dust remover for high temperature gas according to the present invention. In the dust remover of the same figure, the opening 13n at the lower end of the communication pipe 13 is expanded in a funnel shape, and an ejector nozzle 20 for ejecting high pressure air is provided below the opening 13n. The jet flow of air or the like ejected from the ejector nozzle 20 pushes the dust-containing gas in the hopper space 7 into the communication pipe 13 by the ejector effect, and promotes the suction of the dust-containing gas into the communication pipe 13. With this configuration, when the pressurized fluidized bed boiler is started, when the load is low, when the fuel is purged from the boiler following the fuel trip, etc.
When it is desired to temporarily increase the reflux rate of the dust-containing gas, the reflux rate can be increased.

FIG. 9 illustrates the present invention in US Pat. No. 5,346,533.
It is a longitudinal cross-sectional view showing an example applied to the candle type dust remover disclosed in FIG.

In FIG. 9, 1'denotes a candle-type dust remover, 30 is a filter tube whose upper end is closed and whose lower end is connected to the clean gas header 100, 110 is a clean gas outlet pipe, and 120 is a clean gas outlet portion. The backwash ejector 140 is an ejector nozzle for injecting compressed air for backwash. The upper portion of the filter tube 30 is supported by a support plate 111 fixed to the clean gas outlet tube 110 so as not to fall. In FIG. 9, the filter tube 3 is a filter tube group attached to two sets of upper and lower clean gas headers 100, and the pressure vessel 2 is formed by the left and right clean gas outlet tubes 110.
A plurality of such filter tube groups are actually mounted in the thickness direction of the paper surface. The same reference numerals as those in FIGS. 1 and 2 denote the same reference numerals as those in FIGS. 1 and 2. The inside of the pressure vessel 2 is shown in FIG.
Insulation is lined as well, but not shown in this figure.

In the dust remover shown in FIG. 9, the dust-containing gas flows into the dust remover 1'through the gas inlet 10 and the wall 15 of the gas inlet.
And the outer periphery of the upper end of the communication pipe 13 has the smallest static pressure in the throat of the diffuser 8, and the dust-containing gas in the hopper space is sucked out from the opening 13m provided in this throat to allow the diffuser 8 To recover static pressure.

As a result, a downward flow of the dust-containing gas can be generated at the lower end of the filter tube 30, that is, at the lower part of the dust removing chamber 60, and abnormal accumulation and bridging of dust generated in a part of the filter tube 30 can be prevented. Therefore, it is possible to secure the flow rate of the dust-containing gas capable of preventing the ignition and combustion of the unburned component at the lower end of the lower filter tube 30 in which the descending flow rate of the gas is minimum in the dust removing chamber 50.

On the other hand, the clean gas filtered by the filter tube 30 descends in the filter tube 30 and is cleaned by the clean gas header 100.
Enter the clean gas outlet pipe 110, the backwash ejector 120
Via the clean gas outlet 12 to the downstream system.

In backwashing, air is ejected from the ejector nozzle 140 sequentially for the upper and lower filter tube groups or for each group of several filter tube groups so that the gas pressure in the clean gas header 100 is lower than the pressure on the dust-containing gas side. And the gas is caused to flow backwards through the filter wall of the filter tube 30.
This is done by removing the dust that has accumulated on the surface of the.

The ejection of air by the ejector nozzle 140 normally takes a valve opening time (a time required from fully closed to fully opened and fully closed) of 0.1 to 0.1 as in the case of the tube type dust remover of FIG.
This is done by opening and closing a control valve (not shown) set to 0.5 seconds. The dust blown off from the upper filter tube group by the backwash moves to the hopper space 7 by riding on the descending gas flow without staying in the upper space of the dust removing chamber 60,
A part is captured by the filter tube group in the lower stage, but a large part falls to the hopper space 7. The state of the gas flow in the hopper space 7 is the same as in the embodiment of FIG.

When the backwashing is carried out, the backwashing gas is ejected from the surface of the filter tube 30 and the gas flow in the dust removing chamber 60 and the hopper space 7 is temporarily disturbed, but the dust-containing gas is constantly extracted from the opening 13n. Therefore, the original gas flow state is immediately restored.

FIG. 10 is a vertical sectional view showing an example in which the dust remover for high temperature gas of the present invention is applied to a so-called Tiered type candle dust remover.

In FIG. 10, 1'denotes a candle type dust remover, 10 a gas inlet, and a cylinder 15 of the gas inlet is a tube plate 5.
It penetrates 0 and is welded to the tube sheet 50. 1
2 is a clean gas outlet, 2 is a pressure vessel, 30 is a filter tube whose one end is closed, 100 is a clean gas header on which the filter tube 30 is suspended, and 110 is a backwash ejector nozzle 1 inside.
A clean gas outlet tube having 40 is suspended on a tube plate 50 that partitions the dust-containing gas space and the clean gas space 90. FIG.
At 0, two sets of upper and lower clean gas headers 100 are suspended on one clean gas outlet pipe 110. A heat insulating material is lined inside the pressure vessel 2 as in the apparatus shown in FIG.

In the dust remover of FIG. 10, the dust-containing gas flows into the dust remover 1'through the gas introduction port 10 and the cylinder 1 of the gas introduction part is introduced.
5, the static pressure becomes the smallest in the throat of the diffuser formed between the gas introduction part and the outer periphery of the upper end of the communication pipe 13, and the dust-containing gas in the hopper space is sucked up from the opening 13m in this throat. Then, the static pressure is restored in the diffuser 8.

The candle type dust removing device of this type has a large dead volume in the dust removing chamber, and unless a considerable amount of dust-containing gas is recirculated from the hopper space 7 to the upstream portion, it is like a combustion gas of a pressurized fluidized bed boiler or the like. When removing dust-containing gas containing sticky dust, it is difficult to avoid dust bridging. According to the present invention, the dust-containing gas can be recirculated to forcibly give a downward flow to the dust-containing gas in the dust removing chamber, the horizontal gas flow in the dust removing chamber 60 can be suppressed, and The downward flow of the dust-containing gas can be ensured even at the lower end of the filter tube group 30 in the lowermost stage where the downward flow velocity of the dust-containing gas is minimized.

On the other hand, the clean gas filtered by the filter tube 30 rises in the filter tube 30 and rises to the clean gas header 100.
Enters the clean gas outlet pipe 110, is collected, and is sent from the clean gas outlet 12 to the downstream system.

In the backwash regeneration of the filter tube 30, the compressed air is ejected from the ejector nozzle 140 at an appropriate time interval so that the gas pressure in the clean gas header 100 becomes higher than the pressure on the dust-containing gas side, and the filter tube 30 is filtered. The backwash gas is passed through the wall in the direction opposite to that at the time of filtration to remove the dust accumulated on the surface of the filter tube 30.

The compressed air ejected from the ejector nozzle 140 normally has a valve opening time (a time required from fully closed to fully open and fully closed) of 0.1 to 0., as in the case of the tube type dust remover shown in FIG. Open and close the control valve (not shown) set to 5 seconds. When the configuration of the present invention is applied to this type of dust remover as well, the dust separated from the upper filter tube 30 by backwash does not stay in the upper space of the dust removing chamber 50 and flows into the hopper space 7 by the downward dust-containing gas flow. And partly captured by the lower filter tube 30,
Most of them fall as they are and are collected in the hopper.

[0076]

EFFECTS OF THE INVENTION The dust remover for high temperature gas according to the present invention can be used for dust removal of high temperature dust-containing gas produced in a combustion process such as a power plant using a pressurized fluidized bed boiler, a direct coal combustion device, or a coal gasification plant. For example, even if dust-containing gas with a high dust concentration is introduced into the dust remover, it is possible to suppress the phenomenon that a large amount of dust accumulates on a part of the filtration surface of the ceramic filter, and dust containing a large amount of unburned components such as soot. Even if the dust is introduced into the dust remover, it is possible to suppress the dust from burning and burning,
Even if dust is ignited, the thickness of the dust deposited on the filter tube is small, so that intense combustion does not occur and stable operation can be performed without causing thermal damage to the filter tube. Therefore, it can be expected that the time for full-scale commercialization of the above-mentioned future coal utilization technology can be hastened, so that its utility value in the energy industry field is great.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a high temperature gas dust remover of the present invention.

FIG. 2 is a vertical sectional view of a portion A of FIG.

FIG. 3 is a detailed vertical cross-sectional view of a portion A of FIG. 1 for explaining movement of the position of the throat of the diffuser during low load and high load.

FIG. 4 is a vertical cross-sectional view showing another embodiment of the gas introduction part of the high-temperature gas dust remover of the present invention.

5 is a detailed vertical cross-sectional view of a B part in FIG.

FIG. 6 is a vertical cross-sectional view of another preferred embodiment of the present invention applied to part B of FIG.

FIG. 7 is a vertical sectional view showing another embodiment of the high temperature gas dust remover of the present invention.

FIG. 8 is a vertical cross-sectional view showing an example of a conventional high-temperature gas dust remover.

FIG. 9 is a vertical cross-sectional view showing another embodiment of the hot gas dust remover of the present invention.

FIG. 10 is a vertical cross-sectional view showing another embodiment of the high-temperature gas dust remover of the present invention.

[Explanation of symbols]

1, 1 ': Dust remover 2: Pressure vessel 3, 30: Filter tube (ceramic filter) 5a, 5b, 5c, 5d, 5e, 5f, 50: Tube plate 6: Gas inlet chamber 7: Hopper space 8: Diffuser 9a , 9b, 9c, 9d, 60: Dust removal chamber 10, 27a: Gas inlet 11a, 11b, 11c, 11d: Clean gas outlet pipe 12: Clean gas outlet 13: Communication pipe 13e, 13a, 13b, 13s, 13c, 13d 1
3h: Communication pipe portion 13n: Opening (suction port) 13m: Opening (suction port) 14a, 14b, 14c, 14d, 140: Ejector nozzle 15: Gas inlet tube 25: Working space 27: Curved tube 90: Clean Gas space 100: Clean gas header 110: Clean gas outlet pipe 120: Ejector

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroshi Ando 1-1 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Asahi Glass Co., Ltd. Keihin Factory (72) Inventor Sadao Ito 4-33 Komachi, Naka-ku, Hiroshima-shi, Hiroshima Chugoku Electric Power Co., Inc. (72) Inventor Sadao Nishimura 4-33 Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture Chugoku Electric Power Co., Inc.

Claims (7)

[Claims] 1. A dust remover comprising a ceramics filter, a container having a dust-containing gas introduction part in the upper part and a hopper space for collecting dusts in the lower part, and a backwashing means for regenerating the ceramics filter. A tube provided at the gas introduction part, which has a communication pipe which is arranged substantially vertically in the center of the container and which connects the dust-containing gas introduction part and the hopper space through openings provided at both ends thereof. A diffuser is formed between the upper end of the communication pipe and an opening provided on the side surface of the upper end of the communication pipe is arranged in the throat of the diffuser having a narrow flow passage cross-sectional area, and the throat of the diffuser and the outlet of the diffuser. The dust removing device for high temperature gas, wherein the dust containing gas in the hopper space is recirculated to the gas introducing portion through the communication pipe due to the static pressure difference of the dust containing gas in the above. 2. A ceramic filter is a filter tube having openings at both ends, and a dust removing chamber whose upper and lower sides are partitioned by horizontal tube plates is provided inside a container. The dust remover for high-temperature gas according to claim 1, wherein the upper and lower ends are respectively held by the upper and lower tube plates, and the dust-containing gas flows inside each filter tube. 3. The communication pipe is formed by vertically connecting a plurality of communication pipe portions, and each communication pipe portion is attached so that each connection pipe portion can be pulled upward from the container. Dust remover for high temperature gas. 4. Dust removal chambers of equal volume are provided in the upper and lower four chambers, and each dust removal chamber is located between two or more dust removal chamber groups in the container which are adjacent to each other with a tube plate interposed therebetween. The dust remover for high-temperature gas according to claim 2 or 3, wherein a working space having a height substantially equal to the above is provided. 5. A high temperature gas according to any one of claims 1 to 4, wherein an ejector or an injector for promoting the inflow of dust-containing gas into the opening is attached to the opening of the communication pipe provided in the hopper space. Dust removal device. 6. The dust remover for high temperature gas according to claim 1, further comprising a swirling means for forcibly swirling the dust-containing gas in the hopper space. 7. The high temperature gas dust remover according to claim 1, wherein the dust-containing gas is a combustion gas of a pressurized fluidized bed boiler.