JPS598168B2 - Dust collection/denitrification equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to combustion exhaust gas (hereinafter simply referred to as exhaust gas).

In particular, it relates to a dust collection/denitrification device that simultaneously removes dust from high-temperature exhaust gas and denitrates it in the same device. In order to decompose and remove nitrogen oxides (hereinafter referred to as NOX) contained in exhaust gas, NH3, H2S, H2CO, CH4
A so-called dry flue gas denitrification device has recently been developed, in which a ring-forming agent such as the following is added to the exhaust gas and brought into contact with a denitrification catalyst to reduce NOx to N2.

However, in the dry denitrification equipment using a catalyst as described above, the catalyst is poisoned by the dust in the exhaust gas, reducing the activity characteristics of the catalyst, so removing dust from the high-temperature exhaust gas becomes an important issue. It's coming.

For this reason, it is possible to install devices such as electrostatic precipitators and bag filters upstream of the denitrification reactor, but since general electrostatic precipitators are made of carbon steel, 350℃), and in order to use it at high temperatures, heat-resistant materials such as stainless steel must be used, making it expensive, and furthermore, there is the problem that dust cannot be completely removed. have. In addition, even if the bag filter is made of heat-resistant glass fiber with ζ5 as the filter material, the temperature is about 280℃.
can only withstand temperatures of 350°C.
It has the disadvantage that it cannot be applied to high-temperature exhaust gas before and after.

As described above, in the past, dust removal and denitrification of exhaust gas had to be carried out by installing expensive dust collectors and denitrification equipment separately, which increased the cost of exhaust gas treatment and was extremely uneconomical. In order to eliminate these shortages, as shown in Japanese Patent Application Laid-Open No. 51-4064, a porcelain packing layer filled with a porcelain material is provided in front of a catalyst layer filled with a denitrification catalyst.
A device has been proposed that removes dust from the exhaust gas in advance, but since the catalyst layer and the packing layer are flat, the device is large-scale, and the dust may adhere to the support in front of the packing layer and fall. There are problems such as difficulty in smoothly discharging large-sized dust particles.

The present invention has been made in view of the above points, and includes an outer porous tube made of a double porous body provided in an outer tube consisting of a cylindrical portion and a conical portion integrally connected to the lower part of the cylindrical portion. A dust collecting material made of sand, gravel, etc. is filled between the double porous bodies of the outer porous cylinder to form a dust collection part, and an inner porous cylinder made of double porous bodies is provided inside the outer porous cylinder. A denitration section is formed by filling a denitrification catalyst between the double porous bodies of this inner porous cylinder so that it can be circulated freely, and an exhaust gas inlet is provided on the side of the outer cylinder in the tangential direction to the outer cylinder, and the upper part of the outer cylinder is A clean gas outlet is provided in the center, a conical passage provided along the inner surface of the conical part is connected to the lower part of the outer porous cylinder, and the intersection of this conical passage is connected from the top of the conical part to the outside of the outer cylinder. A conical passage is connected to the lower part of the inner porous cylinder, and the intersection of the conical passage is extracted from the top of the conical part to the outside of the outer cylinder to form a catalyst extraction passage. By forming an opening for dust entrainment between the lowest part of the outer perforated plate of the outer perforated cylinder and the conical part, and providing a ring agent addition means on the downstream or upstream side of the dust collection part, After the dust in the exhaust gas introduced into the outer cylinder is removed in the dust collection section, the NOx in the exhaust gas is decomposed and removed in the denitrification section. The object of the present invention is to provide a dust collection/denitrification device that can efficiently perform denitrification and denitrification at the same time, and can smoothly discharge large-sized dust that has adhered to the front surface of the dust collection section and fallen. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below based on embodiments shown in the drawings.

Reference numeral 1 denotes an outer cylinder consisting of a cylindrical part 2 and a conical part 3 connected to a funnel body at the lower part of the cylindrical part. It is provided so as to have a cylinder wall and a space 6.

A conical passage 7 provided along the inner surface of the conical part 3 is connected to the lower part of this outer porous cylinder 5, and the intersection of this passage 7 is connected from the top of the conical part 3 to the outside of the external cylinder IS. A dust collection material extraction passage 8 is formed by drawing out the dust collection material, and a dust collection material extraction valve 9 is provided in this passage 8. Between the double perforated plates 4, 4 of the outer perforated tube 5, a dust collecting material 10, 10, . That is, the dust collection material extraction passage 8 is connected to the upper part of the outer porous cylinder 5 via a conveyance means such as a screw conveyor and a snolining device (none of which are shown), and extracts the dust collection material containing dust. The dust collecting material is separated from the dust by processing, and the separated dust collecting material can be circulated. Further, a new dust collecting material replenishing means is connected to the upstream side of the outer porous cylinder 5 so as to be able to replenish the dust collecting material for the amount of waste. Further, inside the outer porous tube 5, an inner porous tube 13 consisting of double perforated plates 12, 12 is provided so as to have a space 14 with the outer porous tube 5.

A conical passage 15 is connected to the lower part of this inner porous cylinder 13,
The intersection of this passage 15 is extracted from the top of the conical part 3 to the outside of the outer cylinder to form a catalyst extraction passage 16.
6 is provided with a catalyst extraction valve 17. A denitrification section 19 is formed by filling denitrification catalysts 18, 18, . That is, the catalyst extraction passage 16 is connected to the upper part of the inner porous cylinder 13 via a conveying means such as a screw conveyor and a processing device such as a water washing/drying device (none of which are shown). The structure is such that the catalyst can be extracted and processed to activate the catalyst and circulated.
Further, a new catalyst replenishing means is connected to the upstream side of the inner porous cylinder 13 so as to be able to replenish the catalyst equivalent to the loss D. On the other hand, NH3, H2S. H
2.CO,. A cyclizing agent addition means 20 for adding a cyclizing agent such as CH4 is provided.

21 is an exhaust gas outlet provided on the side of the outer cylinder 1, 22 is an outer cylinder lid, 23 is a clean gas outlet provided on the outer cylinder lid, and 24 is the lowest part and conical part of the outer perforated plate of the outer perforated cylinder 5. 3 is an opening for drawing in dust.

Note that instead of using a perforated plate as the material for forming the perforated tubes 5 and 13, a porous body such as wire mesh may be used. Since the present invention is configured in this manner, the dust and NO introduced into the outer cylinder 1 from the exhaust gas population 21 are
The exhaust gas containing X is first removed by the dust collector 11.

To explain the dust removal mechanism in more detail, when the exhaust gas passes through the dust collection section 11, the large particle size dust in the exhaust gas adheres to the surface of the outer perforated plate in a layered manner, and the small particle size dust passes through this dust layer. High-performance dust collection is achieved using dust collection materials. When the thickness of the dust layer becomes large, the dust layer peels off from the surface of the perforated plate and falls, and is rolled into the conical passage 7 together with the dust collecting material through the dust entrainment opening 24. The dust collecting material is then sent to a screening device to separate the dust collecting material from the dust, and the separated dust collecting material is circulated to the outer porous cylinder 5 again. In this case, it is necessary to constantly move the dust collection material. Note that instead of providing the dust entrainment opening 24 to entrain dust into the dust collecting material, other means such as a dust extraction valve may be provided. In this case, the dust collection material does not necessarily need to be moved all the time, and may be moved at regular intervals. Next, a ring agent is added to the dust-removed exhaust gas, and then the denitrification section 1
NOX in the exhaust gas comes into contact with the catalysts 18, 18...
is decomposed into N, rendered harmless, and discharged from the clean gas outlet 23.

As an example, the reaction formula for the ammonia-catalyzed ring reduction method is as follows. 6N0+4NH→5N+6H
0 3226N0 +8NH→7N+12H02 When the activity characteristics of the denitrification catalyst decrease, the catalyst extraction valve 1
7 is opened to send the catalyst to a processing device such as a water washing/drying device, where the catalyst is activated and circulated to the inner porous cylinder 13 again.

The catalyst extraction valve 17 is desirably configured to be automatically opened when the activity characteristics of the catalyst decrease. In the above embodiment, the case where the cyclic agent addition means 20 is provided between the dust collection section 11 and the denitrification section 19 has been described, but it is not necessarily necessary to provide it at this position. It may be provided outside, on the upstream side of the dust collecting section, such as in the exhaust gas port 21 or the exhaust gas duct (in the drawing, the case where it is provided in the exhaust gas wide opening 21 is shown by a chain line as an example).

Also, by circulating and mixing a part of the clean gas into the cyclic agent to dilute it and add it. ．． It may be configured to improve the dispersion of the ring agent. In addition, in FIGS. 1 and 2, the arrow shown by a chain line on the side of the exhaust gas population 21 indicates the position where the cyclic agent is added. It is also possible to provide the dust collecting section 11 and the denitrification section 19 in close contact with each other. In this case, it is possible to reduce the number of perforated plates between the dust collection section and the denitrification section to one. Furthermore, instead of using sand or gravel as the dust collecting material, the same catalyst as used in the denitrification section can also be used. In this case, since there is no problem even if the catalysts are mixed with each other, the catalysts can be removed very easily and the manufacturing cost of the device can be reduced. As explained above, according to the dust collection/denitrification device of the present invention, dust removal and denitration of high-temperature exhaust gas of 250 to 400°C can be efficiently performed simultaneously in the same equipment or container. In addition to eliminating the need for separate expensive dust collectors and denitrification equipment as in the past,
It is possible to smoothly discharge large-sized dust that has adhered to the front of the dust collection section and fallen, and also to screen the dust collection material.
Since it is easy to automatically activate the denitrification catalyst, it has the effect that exhaust gas can be treated at low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the dust collection/denitrification apparatus of the present invention, and FIG. 2 is a cross-sectional view thereof. 1...Outer tube, 2...Cylindrical portion, 3...
... Conical part, 4, 12 ... Perforated plate, 5 ...
... Outer porous cylinder, 6, 14 ... Space part, 7,
15...Conical passage, 8...Dust collection material extraction passage, 9...Dust collection material extraction valve, 10.
...Dust collection material, 11 ...Dust collection part, 13
...Inner porous tube, 16...Catalyst extraction passage, 17...Catalyst extraction valve, 18...
・Denitrification catalyst, 19... Denitrification section, 20...
- Ring agent addition means, 21...Exhaust gas population, 22
...Outer cylinder lid, 23...Clean gas outlet,
24...Opening for drawing in dust.

Claims (1)

[Claims] 1. An outer porous cylinder made of a double porous body is provided in an outer cylinder consisting of a cylindrical part and a conical part integrally connected to the lower part of the cylindrical part, and sand, sand, A dust collecting material such as gravel is filled in a freely circulating manner to form a dust collecting section, and an inner porous cylinder made of a double porous material is provided inside the outer porous cylinder, and a dust collecting material such as gravel is filled between the double porous materials of the inner porous cylinder. A denitration section is formed by filling a denitrification catalyst in a freely circulating manner, an exhaust gas inlet is provided on the side of the outer cylinder in the tangential direction to the outer cylinder, a clean gas outlet is provided in the upper center of the outer cylinder, and the outer porous A conical passage provided along the inner surface of the conical part is connected to the lower part of the cylinder, and the intersection of the conical passage is extracted from the top of the conical part to the outside of the outer cylinder to form a dust collection material extraction passage. , a conical passage is connected to the lower part of the inner porous cylinder, an intersection of the conical passage is extracted from the top of the conical part to the outside of the outer cylinder to form a catalyst extraction passage, and an outer perforated plate of the outer perforated cylinder is connected to the conical passage. A dust collection/denitrification device characterized by having an opening for dust entrainment between the lowest part and the conical part.