JPS61268330A - Dust removal apparatus equipped with heat exchanger - Google Patents

Abstract

PURPOSE:To obtain the titled apparatus for performing dust removal without injecting room temp. backwashing gas to a high temp. filter material at the time of backwashing, by providing the blow-off port of a gas stream to the space in a purified gas side while providing a heat exchanger to the flow passage of the aforementioned gas stream. CONSTITUTION:The high temp. dust-containing gas entering from a dust- containing gas introducing port 13 enters a filter cylinder 11 at the time of dust removal operation to remove the dust therein and passes through a diffuser 20 and a dust 25 to be led out from a blower 26. At the time of backwashing, the low temp. gas stream issued from a high pressure pump 28 passes through a coil shaped tubular heat exchanger 31 to be injected from a flow-off port 29. Low temp. backwashing gas is thermally expanded by heat exchange to be heated to high temp. and the jet speed thereof increases. This high temp. gas stream also takes in circumferential high temp. gas by the ejector effect of the throat part 27 to form a large amount of a high temp. backwashing gas stream. Therefore, backwashing can be performed without damaging the filter cylinder 11 such as a solid filter by thermal shock.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a dust removal device, and particularly to a dust removal device having a filter wall made of an air-permeable porous solid.

[Prior Art] Filtration and dust removal devices that use furnace cloth as the furnace material have been widely used in the past, but in these dust removal devices, the temperature of the dust-containing gas does not exceed 250°C because the furnace cloth has poor heat resistance. If it exceeds it, it can no longer be used.

Therefore, the present applicant has proposed a dust removal device that can be used for high-temperature dust-containing gases and is made of a porous porous ceramic material (Japanese Patent Laid-Open No. 59-22572
(see 1). In this dust removal device, dust-containing gas is supplied from above into a cylinder made of a permeable porous solid installed upright, and the clean gas flows out from inside the cylinder to the outside, and is blocked from passing through by the furnace cylinder. A part of the dust accumulates on the inner wall of the furnace cylinder, and most of it falls inside the furnace cylinder and is collected in a dust hopper provided below the furnace cylinder.

By the way, in such a filtration and dust removal device, when dust removal operations are performed continuously, the filter material gradually becomes clogged, the differential pressure required for filtration increases by t, and the filtration speed decreases. For this reason, a so-called backwashing operation is required to remove clogging dust by flowing gas from the clean gas side to the dust-containing gas side every time the dust removal operation is performed for a predetermined period of time.

In a dust removal device using furnace cloth, a high-pressure gas jet nozzle is installed in the clean gas outlet piping during dust removal operation, and an L is installed on the furnace cloth side.
A well-known backwashing method is one in which an opening is not installed in the opposite direction and high-speed gas is spouted from the opening during the backwashing operation. In this method, the temperature of the dust-containing gas used for dust removal is at most 2
In addition to being not very high at 50°C, furnace cloth is generally thin and has flexibility and bendability, so even if backwash air at room temperature is suddenly blown out at high speed toward the cloth, the furnace The fabric does not suffer any damage.

[Problems to be Solved by the Invention] However, the backwashing method used for furnace cloth dust removal cannot be applied to a dust removal device using an air permeable porous solid (hereinafter referred to as a solid filter) as a member.

In other words, the solid filter, which was being used to remove high-temperature dust-containing gases, is also at a high temperature, and when backwashing air at room temperature is suddenly ejected to it, it can damage sintered metals, ceramics, etc. In particular, solid filters made of ceramics, which are thicker than furnace cloth, lack flexibility, and are vulnerable to thermal shock, are subject to excessive thermal stress due to large temperature differences, and may crack. This will occur and lead to damage.

Therefore, the present invention solves such problems that cannot be solved by the conventional technology, and provides a solid filter that is not likely to be damaged even when a backwashing air source at a temperature lower than that of the dust-containing gas, for example, at room temperature, is used. The purpose of this invention is to provide a type dust removal device.

[Means for solving problems and their effects] In other words,
The present invention provides a dust removal device that supplies dust-containing gas to one side of a filter wall made of a porous solid having air permeability, and extracts clean gas from the other side of the filter wall, in which an air flow outlet is provided in a space on the clean gas side. The dust removal device is characterized in that a heat exchanger with the clean gas is provided in the flow path of the air flow.

Therefore, according to the present invention, since the airflow outlet is provided in the space on the clean gas side, the airflow blown out from the outlet flows into the space on the clean gas side and is used as a backwash airflow. And in the second air flow path, high temperature clean air =
Since a heat exchanger is provided to exchange heat between
Even if this airflow is initially at a low temperature, it is heated by heat exchange and the temperature difference between it and the clean gas is reduced. Therefore, even if this heated airflow hits the high-temperature filter wall, the filter wall is prevented from cracking or eventually being damaged due to thermal shock.

Further, according to the present invention, since the thermal energy of the clean gas is used as a heat source for heating the airflow, it is possible to eliminate the need for a separate heat source equipment for heating the backwashing airflow. Furthermore, since heat exchange is not performed with the dust-containing gas even if the gas is at the same high temperature, troubles in the heat exchanger are also prevented.

In the present invention, various types of heat exchangers such as a normal double-tube type, multi-tube type, and plate type can be used as the heat exchanger. This is not limited to heat exchangers that heat low-temperature backwash airflow with high-temperature clean gas flowing at the same time, but is also a heat storage (i-regeneration type) heat exchanger that is installed at a location where clean gas and backwash airflow alternate over time. Exchangers can also be used. Furthermore, a plurality of these various heat exchangers may be used in combination.

In the present invention, the material of the solid filter may be made of sintered metal or the like, but it is preferably made of ceramic inx due to its excellent heat resistance and corrosion resistance. Furthermore, when removing dust from high-temperature dust-containing gas by taking advantage of its heat resistance, consideration must be given to temperature changes such as when starting operation, stopping operation, changing dust removal/backwashing, and the temperature change of the dust-containing gas itself. In this case, it is particularly preferable to use a ceramic material which has excellent thermal shock resistance. Specifically, cordierite, β
- Preferable examples include ceramics such as subodumene, zirconia, and aluminum titanate.

The furnace wall may be shaped like a flat plate, arranged parallel to each other at predetermined intervals, and the partitioned spaces may be configured alternately into a dust-containing gas side and a clean gas side, but this is preferred. Preferably, the furnace wall is formed into a hollow cylindrical shape, particularly a hollow cylindrical cylinder, and the dust-containing gas is fed into the space inside the furnace wall. This allows the space on the clean gas side to communicate and completely surround the outside of the filter wall, reducing the number of clean gas outlet ducts required. Further, by forming the filter into a hollow cylindrical shape, the possibility that the filter wall will be damaged due to the pressure difference on both sides of the furnace wall is minimized. Although the filter wall may be arranged horizontally or inclined, it is preferably arranged vertically. Thereby, it is possible to prevent the dust separated by the furnace from falling one after another and reducing the dust removal efficiency.

A detailed description will be given below with reference to the drawings.

[Configuration of First Embodiment] In FIG. 1, a plurality of hollow cylindrical furnace cylinders 11 are housed in a cylindrical can body 12 at appropriate intervals. The furnace tube 11 is made of an air permeable porous solid made of cordierite ceramics.

A header 14 equipped with a dust-containing gas inlet 13 and a hopper 16 equipped with a dust extraction valve 15 are attached above and below the can body 12 . Multiple (four in Figure 1) tube plates 1
7 is provided inside the can 432 to hold the furnace cylinder 11. The tube sheets 17 are kept airtight with the furnace tube 11 and the can body 12, respectively, and clean gas chambers 18 are formed between adjacent tube sheets 17, respectively. The upper end of the furnace tube 11,
The lower ends are open to a header 14 and a hopper 16, respectively. Note that at least two tube sheets 17 are required, and an intermediate tube sheet may be provided to allow the clean gas chambers 18 above and below to communicate with each other.

A diffuser 20 is provided in the can body 12 corresponding to each clean gas chamber 18 so that the inner periphery of the can body 12 has an enlarged diameter end. Furthermore, an airflow direct hit prevention body 22 is provided at the center of this diameter-expanded end via a support 21.

A duct 25 is connected to the reduced diameter end of the diffuser 20, and the plurality of ducts 25 are collectively connected to a blower 26. Further, the diameter of the duct 25 is reduced at the connection portion with the reduced diameter end of the diffuser 20 to form a throat portion 27 .

The piping from the high-pressure cylinder 28, such as compressed air or compressed nitrogen, enters the interior of the °C gut 25 via a solenoid valve 35, where it forms a coiled tubular heat exchanger 31. Next, an air outlet 28 is formed by opening toward the cylinder 11 at the shaft portion in front of the throat portion 27 . In addition, high pressure cylinder 2
8 may be replaced with other high-speed airflow generating means, such as a baby compressor.

Further, inside the can body 12, an air-permeable heat storage body 32 made of a plate-shaped ceramic honeycomb body or a laminate of wire gauze is disposed so as to cover the enlarged diameter end of the diffuser 20.

[Operation of the first embodiment] This dust removal device operates as follows.

First, during the dust removal operation, high temperature dust-containing gas is introduced from the dust-containing gas inlet 13, distributed and flowing down inside each furnace tube 11. As it flows down, the dust-containing gas is separated by the furnace tube 11, some of the dust is deposited on the inner wall of the furnace tube 11, and most of the dust falls downward and accumulates in the hopper 16. The high-temperature clean gas passes through the filter wall of the furnace cylinder 11, enters the clean gas chamber 18, and is led out to the D2. During this time, the furnace tube 11 gradually becomes clogged with dust, and the filtration resistance increases. Therefore, a backwash operation is performed after a predetermined dust removal operation.

The backwashing operation may be performed on the upper, middle, and lower parts of the furnace cylinder 11 at the same time, but preferably it is performed on each part one by one, while the dust removal operation continues in other parts of the furnace cylinder 11. As a result, the dust removal operation of the dust removal apparatus as a whole is not interrupted.

Describing the case of backwashing the lower part of the furnace tube 11,
First, the electromagnetic valve 35 is opened to blow out a high-speed airflow from the high-pressure cylinder 28 from the blow-off port 28 . During this time, high pressure cylinder 2
The low-temperature airflow coming out of B passes through the coiled tubular heat exchanger 31, where it is heated by receiving heat from the high-temperature clean gas flowing around the coiled tube, and its flow rate is increased by thermal expansion. When it is ejected from the exit 28, the temperature is quite high and the ejector speed is also high. Due to the ejector effect, a large amount of high-temperature clean gas existing in the surrounding area is taken in, making the whole into a multi-star, and the opposite of high temperature. Forms a wash air flow.

Although this high-temperature backwash airflow has a considerable speed, the pressure is slightly negative because the throat portion 27 sucks in surrounding clean gas. Even if such high-speed, negative-pressure backwash air flows directly into the lower clean gas chamber 18, the pressure difference with the dust-containing gas inside the furnace tube 11 is insufficient, and the air flows inside the furnace tube 11. does not flow sufficiently. Therefore, the air is passed through the diffuser 20, during which much of the velocity energy of the high-speed backwash airflow is converted into pressure energy, and the pressure is sufficiently increased at the expanded diameter end of the diffuser 2o. Note that an airflow direct hit prevention body 22 provided on the diffuser 20 and consisting of a disc body having a Mt. Fuji-shaped protrusion, for example.
This action also prevents the possibility that the high-speed backwash airflow flowing through the shaft portion of the diffuser 20 will directly hit the furnace tube 11 and damage the furnace tube 11 due to its velocity energy.

The wash air flow passes through the breathable heat storage body 32, and the backwash air flow is further heated by receiving the heat accumulated in the breathable heat storage body 32 during the dust removal operation. Note that this breathable heat storage body 32 has the effect of attenuating the motion of the backwash airflow and also acts as an airflow direct hit prevention body.

In this way: the backwashing airflow, which is heated to a temperature that does not cause cracks due to thermal shock even when it hits the furnace tube 11, and whose pressure is sufficiently increased, flows into the entire area of the lower clean gas chamber 18, and the furnace tube It passes through the filter wall 11 and flows into the inside of the furnace cylinder 11. At this time, the dust that was clogging the furnace tube 11 is washed out, and the furnace tube 11 is restored to a low pressure loss state again. The backwash airflow that has flowed into the inside of the furnace cylinder 11 is combined with dust-containing gas, passes through the filter wall of the upper or middle cylinder 11, becomes clean gas, and enters the clean gas chamber 18 in the upper or middle stage. , -L stage or middle stage duct 25 and is guided to the blower 28. At that time, some of the clean gas is transferred to the lower duct 25, the throat section 27, and the air user 2.
0 and is circulated to the lower clean gas chamber 28.

In this way, while the dust removal operation continues in the upper and middle stages, the backwashing operation is performed in the lower stage. Even if a low-temperature airflow is ejected, the furnace tube 11 will not be damaged.

Similarly, the backwashing operation can be carried out sequentially in the first stage and the middle stage, and the backwashing operation of the entire dust removal apparatus can be carried out smoothly.

Note that it is also possible to backwash the -L stage, middle stage, and lower stage at the same time; in this case, the supply of dust-containing gas from the dust-containing gas inlet 13 is interrupted, and the high-pressure cylinders 28 of each stage are opened. For example, each clean gas chamber 18 is opened by opening the dust removal valve 15.
The backwash airflow that has flowed into the inside of the empty cylinder 11 is led out from here.

[Configuration and operation of second embodiment] In another embodiment shown in FIG. It functions as an air outlet. In addition. The same parts as in the case of FIG. 1 are given the same numbers and the explanation is omitted.

That is, a clean gas valve 3B is provided in each stage of the tact 25, and a branch duct 37 is connected between the clean gas valve 36 and the can body 12. A diffuser 20 is provided in the branch duct 37 at each stage, and a backwash airflow valve 4 is further provided beyond the diffuser 20.
0 are provided, and then collected and connected to the forced blower 3B. An indirect heat exchanger 38 using a heat medium is provided between the grouped ducts for clean gas and the grouped ducts for backwash air flow.

In this dust removal device, during dust removal operation, each backwash airflow valve 40 is closed, each clean gas valve 36 is opened, and the blower 2B is operated to proceed with dust removal.

Next, if the dust removal operation is to be continued in the second and middle sections of the furnace tube 11 and the backwash operation is to be performed in the lower section of the furnace tube 11, the lower clean gas valve 36 is closed and the lower backwash airflow valve is closed. 40 is opened and the forced blower 38 is activated. For example, the room temperature backwash air flow sent out from the forced blower 38 is heated from the high temperature clean gas flowing in the collective duct for the clean body through the action of the indirect heat exchanger 39, and then heated by the diffuser 20. The gas is pressurized, passes through the lower branch duct 37, is further heated by the breathable heat storage body 32, and enters the lower clean gas chamber 18. In this way, the backwash airflow heated by heat exchange with the heat retained in the clean gas by the indirect heat exchanger 38 and the breathable heat storage body 32 has a sufficiently high temperature, and the furnace cylinder 11 is damaged by thermal shock. The fear of doing so is gone.

The backwash airflow that entered the lower clean gas chamber 18 enters the inside of the furnace tube 11 while washing out the dust that was causing clogging of the furnace tube 11, and then it cleans the wall of the upper or middle section of the furnace tube 11. It passes through, becomes clean gas, and finally reaches blower 2.
6 and sent out of the system. In addition, when backwashing the L stage or middle stage part of the furnace tube It, it is performed in the same way.

[Effects of the Invention 1] As described above, in the dust removal device of the present invention, a backwashing air outlet is provided in the space on the cleaning gas side, and a heat exchanger with the retained heat of the clean gas is provided in the airflow path. Since a heat exchanger is provided, the backwash air stream is sufficiently heated and the filter wall consisting of a solid filter is prevented from being damaged by thermal shock. Furthermore, since the heat retained in the clean gas is utilized as the heating source for this air flow, it is possible to eliminate the need for any other special heating device.

In the above embodiment, the flow path for clean gas during the dust removal operation and the flow path for the backwash air flow during the backwash operation partially overlap, but for example, if the can body has a clean gas outlet and The air outlet for backwashing may be opened independently. Further, the diffuser may be omitted depending on the case.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a dust removal device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a dust removal device according to another embodiment of the present invention.

Claims (1)

[Claims] 1. In a dust removal device that supplies dust-containing gas to one side of a filter wall made of a porous solid with breathability and extracts clean gas from the other side of the filter wall, an airflow outlet is provided in the space on the clean gas side. A dust removal device characterized in that a heat exchanger with the clean gas is provided in the flow path of the air flow.