JPH0222689B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dust removal device for high-temperature gas having a cylinder made of an air-permeable porous solid inside a can.

[Prior Art] Excessive dust removal devices made of cloth have been widely used in the past, but in the case of such dust removal devices,
Because the cloth has poor heat resistance, the temperature of the dust-containing gas is 250℃.
If it exceeds ℃, 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 (see Japanese Patent Laid-Open No. 59-225721). In this dust removal device,
Dust-containing gas is supplied from above into an upright cylinder made of a permeable porous solid, and the clean gas flows out from the inside of the cylinder to the outside, while some of the dust that was blocked from passing by the cylinder is Deposits on the inner wall of the cylinder,
Most of the dust falls inside the cylinder and is collected in a dust hopper installed at the bottom of the cylinder.

By the way, in such an excessive dust removal device, when dust removal operations are performed continuously, the material gradually becomes clogged, the differential pressure required increases, and the overspeed 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 dust removal equipment that uses cloth, a high-pressure gas jet nozzle is installed in the clean gas outlet piping during dust removal operation, with its opening facing the cloth side, and high-speed gas is jetted from there during backwash operation. The method is well known. In this method, the temperature of the dust-containing gas used for dust removal is only 250°C, which is not very high, and the cloth is generally thin and has flexibility and bendability, so backwashing airflow at room temperature is Even if it is suddenly sprayed at high speed towards the cloth, the cloth will not be damaged in any way.

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

In other words, the solid filter, which had been removing dust from high-temperature dust-containing gases, is also at a high temperature, and when backwashing air at room temperature is suddenly ejected to the solid filter, it can cause damage to sintered metals, ceramics, etc. In particular, solid filters made of ceramics, which are thicker than cloth, lack flexibility, and are vulnerable to thermal shock, are subject to large temperature differences.
Excessive thermal stress will cause cracks to occur, leading to damage.

Therefore, the present invention solves these problems that cannot be addressed with the prior art, and makes it difficult to damage solid filters 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 the present invention is to provide a solid filter type dust removal device.

[Means for Solving the Problems and Their Effects] That is, the present invention supplies dust-containing gas to one side of a cylinder made of a porous solid having air permeability disposed inside a can, and supplies dust-containing gas from the other side of the cylinder. A dust removal device for extracting clean gas, characterized in that an outlet flow path from the can for clean gas is used as an introduction flow path for a backwash air flow, and a breathable heat storage body is provided in the outlet flow path. This is a dust removal device for use.

Therefore, in the dust removal device for high temperature gas of the present invention,
Since the outlet passage from the clean gas can is used as the introduction port for the backwash airflow, the backwash airflow introduced from this outlet passage flows into the space on the clean gas side inside the can and cleans the cylinder. It is configured to backwash and regenerate.
At this time, the flow path of this airflow is provided with a breathable heat storage body that exchanges heat with the discharged high-temperature clean gas, so even if this airflow is initially low temperature, it is heated by heat exchange. The temperature difference with the clean gas is reduced. Therefore, even if this heated airflow hits the high-temperature tube, the tube is prevented from cracking due to thermal shock and eventually breaking.
Further, according to the present invention, since the thermal energy of the clean gas is used as a heat source for heating the backwash airflow, it is possible to eliminate the need for separate heat source equipment for heating the backwash airflow. Furthermore, even if the gas is at the same high temperature, there is no heat exchange with the dust-containing gas, so troubles such as clogging of the heat storage body do not occur.

In the present invention, as a heat exchanger, an air-permeable heat storage body (regenerative heat exchanger) is used, which is installed in a part where clean gas and backwash air flow alternately over time. Various types of heat exchangers such as type, multi-tube type, and plate type may be used together.

In the present invention, the solid filter may be made of sintered metal or the like, but it is preferably made of ceramic because of 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, ceramic materials such as cordierite, β-spodium, zirconia, and aluminum titanate are preferably used.

The wall is a hollow cylindrical tube, especially a hollow cylindrical tube, and when dust-containing gas is supplied to the inner space, the space on the clean gas side communicates and surrounds the outside of the tube. Therefore, the required number of clean gas outlet ducts can be reduced. Further, by forming the wall into a hollow cylindrical shape, the risk of damage to the wall due to the pressure difference on both sides of the wall is minimized. Although the tube may be arranged horizontally or inclined, it is preferably arranged vertically. Thereby, it is possible to prevent the separated dust 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 the first embodiment] In FIG. 1, a plurality of hollow cylindrical tubes 11 are connected to a cylindrical can body 12 at appropriate intervals.
is housed in. The tube 11 is made of a porous, breathable 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 connected to the can body 1.
It is attached above and below 2. A plurality of tube sheets 17 (four in FIG. 1) are provided inside the can body 12 to hold the tube 11. The tube sheets 17 are kept airtight with the tube 11 and the can body 12, respectively, and clean gas chambers 18 are formed between adjacent tube sheets 17, respectively. The upper and lower ends of the cylinder 11 are open to a header 14 and a hopper 16, respectively. It is sufficient that there are at least two tube sheets 17, and the intermediate tube sheet has clean gas chambers 18 above and below it.
It may also be something that allows communication between the two.

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

A duct 25 is connected to the reduced diameter end of the differential user 20, and the plurality of ducts 25 are collected and connected to the blower 2.
6. Further, the diameter of the duct 25 is reduced at the connection portion with the reduced diameter end of the differential user 20 to form a throat portion 27 .

High pressure cylinder 28 such as compressed air or compressed nitrogen
The piping from the duct enters the interior of the duct 25 via a solenoid valve 35, where it forms a coiled tubular heat exchanger 31. Next, the shaft section in front of the throat section 27 is opened toward the cylinder 11 to open the air outlet 2.
9 is formed. Note that in place of the high-pressure cylinder 28, other high-speed airflow generating means, such as a baby compressor, may be employed.

Further, an air-permeable heat storage body 32 made of a plate-shaped ceramic honeycomb body or a laminate of wire gauze is disposed inside the can body 12 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 dust removal operation, high-temperature dust-containing gas is introduced from the dust-containing gas inlet 13 and is distributed to each cylinder.
It flows down the inside of 1. As it flows down, the dust-containing gas is separated by the cylinder 11, and some of the dust flows into the cylinder 1.
Most of the dust accumulates on the inner wall of the hopper 16 and falls downward and accumulates in the hopper 16. The high temperature clean gas passes through the wall of the cylinder 11, enters the clean gas chamber 18, passes through the diffuser 20 and the duct 25, and is led out from the blower 26. During this time, the cylinder 11 gradually becomes clogged with dust, and the excessive resistance increases. Therefore, a backwashing operation is performed after a predetermined dust removal operation.

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

When backwashing the lower part of the cylinder 11, first open the solenoid valve 35 to flush the high pressure cylinder 2.
8 and blows out a high-speed airflow from the outlet 29.
During this time, the low-temperature airflow coming out of the high-pressure cylinder 28 passes through the coiled tubular heat exchanger 31, where it receives heat from the high-temperature clean gas flowing around the coiled tube, is heated, and increases the flow rate by thermal expansion. When the air is forced to flow and is ejected from the air outlet 29, the ejection speed also increases. Due to the ejector effect of the throat portion 27, this heated high-temperature airflow also takes in a large amount of high-temperature clean gas existing in the periphery, increasing the amount as a whole and forming a considerably high-temperature backwashing airflow.

Although this backwash airflow has a considerable speed,
In terms of pressure, the throat portion 27 sucks in surrounding clean gas, so the pressure is somewhat negative. Even if such a high-speed, negative-pressure backwash air flow directly flows into the lower clean gas chamber 18, the pressure difference between the dust-containing gas inside the cylinder 11 and the dust-containing gas inside the cylinder 11 is insufficient, and the inside of the cylinder 11 is not sufficiently filled. does not flow into the Therefore, the air is passed through the differential user 20, during which time the velocity energy of the high-speed backwash airflow is converted into a large amount of pressure energy, and the pressure is sufficiently increased at the expanded diameter end of the differential user 20. Note that due to the action of the airflow direct hit prevention body 22 which is provided on the differential user 20 and is made of a disc body having a Mt. The risk of damaging the cylinder 11 due to energy is also prevented.

In this way, the pressurized backwash airflow leaving the diff user 20 passes through the breathable heat storage body 32, and at this time,
The backwash airflow is further heated by 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 dynamic pressure of the backwash airflow, and also acts as an airflow direct hit prevention body.

In this way, even when the backwash airflow hits the cylinder 11, the cylinder 11 is heated to a temperature that does not cause cracks due to thermal shock, and the sufficiently pressurized backwash airflow is applied to the entire area of the lower clean gas chamber 18. Inflow, cylinder 1
1 and flows into the inside of the cylinder 11. At this time, the dust that had caused clogging in the tube 11 is washed out, and the tube 11 is restored to a low pressure loss state again. The backwash air flow that has flowed into the inside of the cylinder 11 is combined with dust-containing gas, passes through the wall of the upper or middle cylinder 11, becomes clean gas, enters the upper or middle clean gas chamber 18, and is then transferred to the upper or middle cylinder 18. Alternatively, it is guided to the blower 26 through the middle duct 25. At that time, some of the clean gas is transferred to the lower duct 25, the throat section 27, and the diffuser 2.
0 to the lower clean gas chamber 18.

In this way, the dust removal operation is continued in the upper and middle stages, while the backwashing operation is performed in the lower stage. Even if a low-temperature airflow is ejected, a backwash airflow at a temperature that will not damage the cylinder 11 is supplied.

Similarly, the backwashing operation is sequentially performed in the upper stage and the middle stage, so that the backwashing operation of the entire dust removal apparatus can proceed smoothly.

It is also possible to backwash the upper, middle and lower stages at the same time, in which case the dust-containing gas inlet 13
The supply of dust-containing gas from
is opened, and the backwash airflow that has flowed into the inside of the tube 11 from each clean gas chamber 18 is led out from here.

[Configuration and operation of the second embodiment] In another embodiment shown in FIG. It functions as an exit. Incidentally, 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 3 is installed in each stage of the duct 25.
6 is provided, and a branch duct 37 is connected between the clean gas valve 36 and the can body 12. A differential user 20 is provided in each stage of the branch duct 37,
Furthermore, a backwash airflow valve 40 is provided beyond that, and then they are assembled and connected to the forced blower 38. An indirect heat exchanger 39 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 air flow valve 40 is closed, each clean gas valve 36 is opened, and the blower 26 is operated to proceed with dust removal.

Next, when performing a backwash operation in the lower part of the cylinder 11 while continuing the dust removal operation in the upper and middle parts of the cylinder 11, the lower clean gas valve 36 is closed, the lower backwash air flow valve 40 is opened, and the pump is pressed. Blower 3
8 is activated. For example, the room-temperature backwash air flow sent out from the forced blower 38 is heated by the high temperature clean gas flowing in the collected clean gas ducts through the action of the indirect heat exchanger 39, and then the pressure is increased by the diffuser 20. and the lower branch duct 3
7, it is further heated by the breathable heat storage body 32 and enters the clean gas chamber 18 in the lower stage. The backwash airflow heated by heat exchange with the heat retained in the clean gas by the indirect heat exchanger 39 and the air-permeable heat storage body 32 has a sufficiently high temperature and damages the cylinder 11 due to thermal shock. Fear is gone.

The backwash airflow that entered the lower clean gas chamber 18 enters the inside of the cylinder 11 while washing out the dust that was clogging the cylinder 11.
The gas passes through the walls of the upper or middle portion of the air filter 1, becomes clean gas, and is finally sent out of the system from the blower 26. Note that the same procedure is performed when backwashing the upper or middle portion of the cylinder 11.

[Effects of the Invention] As described above, in the high-temperature gas dust removal device of the present invention, the outlet flow path from the clean gas can is used as the inlet for the backwashing air flow, and the flow path for this air flow is Since the air-permeable heat storage body is provided to exchange heat with the heat retained in the clean gas, the backwash air flow is sufficiently heated and the cylinder made of the 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.

This breathable heat storage body has a simple structure, such as a plate-shaped ceramic honeycomb body or a laminate of wire mesh, and can heat the backwashing airflow to the necessary and sufficient level, and there is no risk of failure and the installation cost is low. In addition, it also has the effect of relaxing the flow velocity distribution and temperature distribution of the backwash airflow.

[Brief explanation of drawings]

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)

[Scope of Claims] 1. A dust removal device that supplies dust-containing gas to one side of a cylinder made of a porous solid having air permeability disposed inside a can body, and extracts clean gas from the other side of the cylinder. A dust removal device for high-temperature gas, characterized in that an outlet flow path from the can body is used as an introduction flow path for a backwash air flow, and a breathable heat storage body is provided in the outlet flow path. 2. The dust removing device for high temperature gas according to claim 1, wherein the dust-containing gas is supplied to the inside of the cylinder, and the outlet flow path for the clean gas from the can is provided on the side of the can. 3. The high-temperature gas dust removal device according to claim 1 or 2, wherein the porous solid cylinder having air permeability is made of ceramics.