JPS641187B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a dry scrubber that can remove dust and water droplets from gas containing dust and water droplets, and is particularly suitable for use in extremely cold regions. This is an improved version.

[Conventional technology]

BACKGROUND ART Conventionally, a dry scrubber having a structure as shown in FIG. 1 has been employed as a dry scrubber for removing dust and water droplets from gas or blast furnace gas transported via a gas pipeline. This dry scrubber is currently commonly used as a cyclone separator. In FIG. 1, a gas inlet 1 is provided in a cylindrical body 11 of a container 3 constituting the main body of the dry scrubber.
A gas outlet 2 is provided at the top of the container, and the lower part of the container is formed as a tapered dust bunker 9, and a dust discharge nozzle 10 is provided at the bottom of the container.
is provided. An upper support plate 7 that supports the riser pipe 4 and a lower support plate 8 that supports the separator 5 integrated with the riser pipe 4 are provided above and below the cylindrical body 11 of the container 3. The gas is introduced into the space between the upper and lower support plates 7 and 8. The separator 5 is provided with a cone 6 into which the lower end of the riser tube 4 is inserted up to a midway height, and whose lower inner surface is formed into a conical shape. The separator 5, as shown in the horizontal cross-sectional view of FIG. It is designed to remove dust and water droplets by creating a swirling flow.

This dry scrubber removes dust entering from gas inlet 1.
Gas containing water droplets and the like is separated by the separator 5, and dust and the like are discharged diagonally downward from the dust discharge port 26 of the cone 6, through the inside of the dust bunker 9, and then discharged to the outside from the dust discharge nozzle 10. On the other hand, the gas from which dust and the like have been removed rises through the riser pipe 4, passes through a chamber above the upper support plate 7 in the container 3, and is taken out from the gas outlet 2.

However, this conventional type of dry scrubber has the disadvantage that the separation efficiency cannot be made very high due to the so-called breathing effect. FIG. 3 is a diagram explaining this. Since the dust outlet 26 of the cone 6 is formed in a conical shape, the air flow near the periphery of the dust outlet 26 is directed diagonally downward as shown by arrow A. On the other hand, since there is an upward flow as shown by arrow B at the center of the dust discharge port 26, the dust, etc. that should be discharged in the direction of arrow A is caused by the upward flow at the center of the cone 6. A phenomenon occurs in which the air enters the riser tube 4 and rises. For this reason, the separation efficiency is not good.

As shown in Fig. 4, as a conventional type that eliminates such drawbacks, a plurality of small dust discharge ports 27 are provided at the bottom of the lower end of the cone 6, so that once separated dust, etc. can be returned to the riser pipe. There are some items that are not included in 4.

The structure shown in Fig. 4 has good separation efficiency, but because the dust discharge port 27 is small, the dust discharge is caused by water droplets, adhesive dust containing moisture (moisture dust), or coarse dust. A drawback is that the outlet 27 is clogged.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a dry scrubber that has good separation efficiency and does not cause clogging.

In order to achieve the above purpose, the following configuration can be considered (hereinafter referred to as a draft plan).

(i) In the prior art, there was a paradoxical problem in that when trying to increase separation efficiency, clogging tends to occur, and when preventing clogging, separation efficiency decreases.

In order to solve this problem, one large cyclone air cleaner type gas purifier is provided and a plurality of small cyclone type separators are provided.

(ii) The large gas purifier and the small separator group are connected in series, and a plurality of separators are arranged in parallel inside the small separator group.

Here, "large" means having a diameter that is 1/2 or more compared to the diameter of the cylindrical body that forms the outer casing, and 2
It means a size that cannot accommodate more than one item. Comparatively, "small" means a size that allows multiple units to be stored side by side.

(iii) The outer casing is divided into upper, middle, and lower parts, with a large cyclone type gas purifier provided as a primary cleaner in the lower part, and a plurality of small cyclone type separators provided in the middle part as a secondary cleaner.

(iv) Since the above-mentioned secondary cleaner is located in the middle stage, the foreign matter separated here is guided downward by a pipe that penetrates the lower stage chamber.

According to the above proposal, large foreign objects can be removed in advance using one large gas purifier. Since it is large, there is little gas flow resistance, and since there is only one, the structure is simple, the cost is low, and maintenance is easy.

Further, although a small separator has a relatively high gas flow resistance, by providing a plurality of separators in parallel, the flow resistance can be reduced.

Furthermore, since the foreign substances separated by the small separator are small particles and in a small amount, a thin discharge pipe is sufficient. Moreover, this discharge pipe cannot be made very thick because it passes through the lower chamber.

[Problems to be Solved by the Invention] The above describes the known technologies related to dry scrubbers and the proposals that can be considered relatively easily based on the known technologies. When such dry scrubbers are used in extremely cold regions, the problem of preventing freezing becomes more prominent.

For example, when considering a dry scrubber as a cleaning means for using Siberian natural gas as gas turbine fuel in cooperation with the Siberian development, moisture in the natural gas and components that are easily liquefied sublimate and precipitate in the form of a sherbet. There is a serious problem in that it mixes with dust and interferes with the scrubber's function.

In order to prevent such freezing in a broad sense, everyone should consider ``installing heaters in areas where moisture (including components that are easily liquefied; the same applies hereinafter) and dust are separated.'' However, if a means (heater) for heating the separation action area (for example, the cone 6 in FIG. 4) of the conventional dry scrubber is installed, (a) the internal structure of the dry scrubber becomes complicated; (b) Maintenance of the heater section is extremely difficult; (c) the function of the scrubber may be affected by the installation of the heater; and (d) the heater has poor thermal efficiency because it is cooled by a gas flow.

The present invention has been made in view of the above circumstances, and has the following features: (a) the internal structure of the dry scrubber is not complicated, (b) maintenance of the heater part is easy, and (c) the installation of the heater It is an object of the present invention to provide a dry type scrubber that does not have any risk of affecting its function as a scrubber.

[Means to solve the problem]

The dry scrubber of the present invention, which was created to achieve the above object, is an improvement on the dry scrubber of the above-mentioned draft. (ii) A heater is provided to heat the dust extraction pipe from the outside through the cylindrical body.

[Effect]

According to the above configuration, since the heater is provided outside the cylindrical body, maintenance is easy, and there is no risk of affecting the gas flow or being cooled by the gas flow.

〔Example〕

Next, one embodiment of the present invention will be described with reference to FIGS. 5 and 6. In FIGS. 5 and 6, 12 is a cyclone constituting the first stage separator section,
The cyclone consists of a first-stage support plate 22 provided at an intermediate position of the cylindrical body 11 of the container 3 constituting the main body of the dry scrubber, and a cylindrical structure that hangs down from an opening in the center of the first-stage support plate. A first stage riser pipe 15 is provided concentrically with the body 11, and a lower part 21a is provided concentrically so as to surround the riser pipe 15, and an opening is formed at the lower end of the cone part 21a. As shown in FIG. 6, the gas inlet 1 provided in the tangential direction of the first stage cylindrical body 21 and the inside of the first stage cylindrical body 21 are communicated with each other. It consists of a gas introduction part 20 provided on an extension of the gas inlet 1 in order to A first stage dust bunker 23 is formed at the lower part of the cone part 21a of the first stage cylindrical body 21 by the end plate part 28 of the container 3, and the dust accumulated in the first stage dust bunker 23 is transferred to the end plate part 28. The first
The stage dust is taken out from the stage dust discharge nozzle 18.

On the other hand, on the upper part of the first stage support plate 22, a first
A second stage separator section is configured to remove fine dust from the coarse dust-separated gas rising through the stage riser pipe 15. 29 is on the top of the first stage support plate 22,
This is a dust collecting cylindrical body installed between the support plate 22 and the cylindrical body 11 with a gap 30 forming a gas flow path, and the lower part thereof is formed into a cone shape 29a. The cylindrical body 29 is provided with a top plate 31,
A plurality of second-stage separators 17 are supported through the top plate, and the second-stage riser pipes 16 that raise the gas removed by the second-stage separators have their upper end openings connected to the container 3. It is supported and attached by a second stage support plate 32 fixed inside the upper end portion of the cylindrical body portion 11 . On the other hand, the lower cone portion 29a of the dust collecting cylindrical body 29 is connected to the cylindrical body 1 of the container.
1, and is connected to a second stage dust extraction pipe 13 provided along the inner wall of the second stage dust extraction pipe 1.
The lower end of 3 communicates with the inside of a second stage dust bunker 24 formed by partitioning the first stage dust bunker 23 and a partition plate 25, and the fine dust accumulated in the second stage dust bunker 24 is transferred to the end plate portion 28. The dust is taken out from the second stage dust discharge nozzle 19 provided in the.

As shown in FIG. 6, the second-stage dust extraction pipe 13 is placed along the inner wall surface of the cylindrical body 11 forming the outer casing of the scrubber, and along the wall of the cylindrical body 11. A heater 14 is provided on the outside. When the heater is provided in this manner, even when the temperature of the inflowing gas is low, there is no risk that the inner surface of the take-out pipe 13 will freeze and become clogged.

In this configuration, when gas containing dust and water droplets is introduced into the first stage cylindrical body 21 from the gas inlet 1, the gas inlet 1 and the gas introduction part 20 are tangentially moved with respect to the first stage cylindrical body 21. As a result, a swirling flow is generated, and coarse dust, water droplets, and sticky dust containing moisture (moisture dust) are moved to the first stage cylindrical body 21 and its surroundings by centrifugal force and adhesive force. The dust flows down along the inner wall of the cone portion 21a, passes through the opening 21b, accumulates in the first stage dust bunker 23, and is taken out from the first stage dust discharge nozzle 18.

On the other hand, the gas from which coarse dust, water droplets, or moisture-containing dust has been removed rises through the first stage riser pipe 15 and reaches the second stage separator 17 through the flow path 30. This second stage separator 17 is a member similar to the conventional separator 5 shown in FIG. In the second stage separator 17, fine dust and fine water droplets are removed, ascend the second stage riser pipe 16, pass through the chamber above the support plate 32, and are taken out from the gas outlet 2. Further, the fine dust and fine water droplets separated by the second stage separator 17 are transferred to the second stage cylindrical body 29 and the second stage separator 17.
2nd stage dust bunker 2 via stage dust extraction pipe 13
4 and is taken out from the second stage dust discharge nozzle 19.

In this way, by separating coarse dust etc. by the first stage separator section 12 and then separating fine dust etc. by the second stage separator 17, the second stage separator section 12 separates fine dust etc.
Even if a highly efficient separator such as that shown in FIG. 4 is used as the stage separator 17, clogging will not occur and the performance of the second stage separator 17 can be fully demonstrated. That is, a highly efficient dry scrubber can be realized.

In addition, in this embodiment, since the gas introduction part 20 is oriented in the tangential direction of the first stage cylindrical body 21 to generate a swirling flow, the structure is similar to that normally used in this type of scrubber. That is, compared to a system that generates a swirling flow by providing a partition plate in the gas introduction section to change the gas flow, pressure loss is lower, high separation efficiency is obtained, and water droplets and coarse dust can be sufficiently removed.

Furthermore, in this embodiment, since the first-stage dust discharge system and the second-stage dust discharge system are provided separately, backflow does not occur in the second-stage dust discharge system (the second-stage dust discharge system The internal pressure of the dust extraction pipe 13 is mainly caused by pressure loss in the second stage separator 17, and is lower than the internal pressure of the first stage dust bunker 23). In addition, because the discharge systems are provided separately, there is no need to control the pressure of the separators in the first and second stages, making it possible to select the best design point for each, and it is easy to operate and expensive. Separation efficiency can be maintained.

A heater as shown at 14 in FIG. 6 is provided on the outer surface of the cylindrical body portion 11 of the container at a location corresponding to the attachment portion of the second stage dust extraction pipe 13. As a result, even when the temperature of the inflowing gas is low, the extraction pipe 1
It is possible to prevent the phenomenon in which the inner surface of No. 3 freezes and fine dust and moisture cannot flow downward.

FIGS. 7 and 8 show an application example of the present invention, and this application example is based on the first stage cylindrical body 2
1 is omitted, and instead of the first stage cylindrical body, a container 13 is used.
The cylindrical portion 11 is used as a component of the first stage separator. In this embodiment, the separation efficiency of coarse dust, water droplets, etc. is slightly lower than that of the previous embodiment, but it has the advantage that the structure is simple and maintenance is very easy.

As described above, according to the dry scrubber of the present invention, even if the temperature of the suction gas is low, there is no risk that the function will be inhibited by freezing, and maintenance is easy.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an example of a conventional dry scrubber, Fig. 2 is a horizontal sectional view of the separator in the above conventional example, and Fig. 3 is an enlarged sectional view of the separator part to explain the problems of the conventional example. 4 is a vertical sectional view showing another conventional example of a dry type scrubber, FIG. 5 is a vertical sectional view showing an embodiment of the dry type scrubber according to the present invention, and FIG. Fig. 7 is a vertical cross-sectional view showing an example of application of the present invention, and Fig. 8 is a B--B thereof.
FIG. 1... Gas inlet, 2... Gas outlet, 3... Container, 11
...Cylindrical body part, 12...First stage separator part, 13...
2nd stage dust extraction pipe, 14...heater, 15...first
Stage riser pipe, 16...Second stage riser pipe, 17...Second
stage separator, 18...first stage dust discharge nozzle,
19... Second stage dust discharge nozzle, 20... Gas introduction part, 21... First stage cylindrical body, 22... First stage support plate,
23...First stage dust bunker, 24...Second stage dust bunker, 29...Cylindrical body for dust collection, 32...Second stage support plate.

Claims (1)

[Claims] 1 (a) The inside of the cylindrical body, which is a vertical cylindrical outer casing,
It is divided into three chambers, upper, middle, and lower, by the first and second stage support plates in the form of horizontal partition plates. The side wall of the lower chamber is provided with an inlet for unpurified gas, and the bottom of the lower chamber is provided with the first stage dust bunker and the first stage dust bunker.
a stage dust discharge nozzle, a second stage dust bunker, and a second stage dust discharge nozzle; (c) a cyclone type gas purifier attached to a second stage support plate is provided in the lower chamber;
(d) arranging a plurality of cyclone separators in the middle chamber to allow the foreign matter in the separated gas to fall into the first stage dust bunker and guide the gas from which the foreign matter has been removed into the middle chamber; (e) A second stage dust extraction pipe is provided to allow the gas sent from the cyclone type gas purifier to pass through the plurality of sets of separators in a divided manner and to guide foreign substances in the separated gas to the second stage dust bunker; (e) In a dry scrubber having a structure in which a second stage riser pipe for guiding clean gas from each of the plurality of sets of separators is fixed to the first stage support plate to guide the clean gas into the upper chamber, (f) The second stage dust extraction pipe in the above item (d) is installed along the inner surface of the cylindrical body, and a heater is installed on the outside of the cylindrical body in correspondence with the dust extraction pipe. Dry scrubber with special features.