JPS6223542Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a dust removal device for a denitrification reactor, and in particular, the dust attached to the inside of the denitrification reactor is removed using the exhaust gas itself. The present invention relates to a dust removal device for a denitrification reactor that can achieve energy savings in removal processing and significantly reduce the operating costs of the entire plant.

[Technical background of the invention and its problems] In a denitrification reactor for removing nitrogen oxides contained in the exhaust gas of a boiler, etc., if the exhaust gas to be treated contains dust, The dust adheres to and accumulates on the catalyst layer, walls, reinforcing beams, etc., leading to a decline in denitrification performance, and increasing pressure loss, which affects plant operation.

To this end, conventionally, a soot blower using air or steam was installed inside the reactor to remove the adhering dust, or the mesh size of the catalyst layer was increased to prevent dust from adhering to the catalyst layer. It prevented accumulation.

However, as mentioned above, when air or steam is used, the operating costs for injecting them will increase, and increasing the mesh size of the catalyst layer will inevitably increase the amount of gas per unit volume of the catalyst. The contact area decreases, and therefore, in order to obtain a predetermined denitrification performance, it is necessary to increase the amount of catalyst packed into the reactor, which is not economical.

The present invention focuses on the above-mentioned problems and has been devised to effectively solve them.

[Purpose of the invention] The purpose of the invention is to remove the dust attached to the denitrification reactor using the exhaust gas itself, thereby achieving energy savings in the dust removal process and reducing the operating costs of the entire plant. The purpose of the present invention is to provide a dust removal device for a denitrification reactor that can perform the following steps.

[Summary of the invention] This invention is a denitrification reactor for exhaust gas such as a boiler, and the exhaust gas flowing into the catalyst layer is deposited on the upstream side of the catalyst layer in the denitrification reactor by changing its flow direction and flow rate. The above objective is achieved by providing a current plate for removing dust.

[Embodiment of the invention] A preferred embodiment of the invention will be described below in detail with reference to the accompanying drawings.

Figure 1 is a schematic vertical cross-sectional view of the denitrification reactor;
The figure is a front view showing a first embodiment of the dust removal device according to the present invention, and FIGS. 3 and 4 are perspective views showing the operation of the first embodiment of the present invention.

As shown in FIG. 1, the denitrification reactor 1 includes a catalyst layer 3 in a casing 2 along the flow direction of the exhaust gas to be treated.
It is constructed by providing the following. A to-be-treated gas inlet 4 is provided in the upper part of the casing 2, and a to-be-treated exhaust gas transfer passage 6 having a nozzle 5 for adding ammonia gas into the to-be-treated exhaust gas being transferred is connected to this inlet 4. ing.
Furthermore, a gas outlet 7 is provided at the lower part of the casing 2 for discharging the denitrified exhaust gas.

A dust removal device 9 according to the present invention is provided upstream of the catalyst layer 3 in the exhaust gas flow, that is, above the catalyst layer 3 in the illustrated example. Specifically, as shown in FIGS. 2 to 4, this dust removal device 9 includes a large number of rectifying plates 10 formed into rectangular shapes.
It is mainly composed of... These rectifying plates 1
0 are integrally attached and fixed to a plurality of rotating shafts 11 which are disposed above the catalyst layer 3 so as to be perpendicular to each other and are rotatably supported by penetrating the casing 2 at both ends. By rotationally displacing the rotating shaft 11 by an appropriate angle and changing the angle of the current plate 10, the direction of the gas flow and the area of the flow path can be changed.

An angle control means 12 using a pulse motor or the like as a drive source is attached to one end of the rotating shaft 11, so that the rotating shafts 11 arranged in the same direction can be rotated synchronously and by the same angle (see Figures 3 and 4).

In the illustrated example (Fig. 2), a rectifying plate group 10a attached to a rotating shaft 11a parallel to the plane of the paper and a rectifying plate group 10b attached to a rotating shaft 11b perpendicular to the plane of the paper are provided, and the exhaust gas flow is can be changed in mutually orthogonal directions.

The operation of these current plate groups 10a and 10b is as follows.
As shown in FIG. 4 and FIG. 4, when operating one group of rectifying plates, for example, the rectifying plate group 10a, the other rectifying plate group 10b is held parallel to the flow direction of the exhaust gas, and the rectifying plate group 10a is held parallel to the flow direction of the exhaust gas. , 10b from interfering with each other.

In the illustrated example, two groups of baffle plates are arranged perpendicularly to each other in order to increase the displacement directions of the gas flow, but it goes without saying that only one group may be provided.

Next, the operation of the present invention will be explained.

First, the treated exhaust gas mixed with ammonia gas is introduced into the casing 2 through the treated gas inlet 4, is passed through it while being in contact with the catalyst layer 3, and is subjected to denitrification treatment. Discharge from 7. In steady state, all current plates 1
0 is maintained parallel to the gas flow,
The exhaust gas flow is rectified.

As gas is passed through the denitrification reactor, dust 14 tends to adhere to the inner wall of the reactor 1, the catalyst basket 3, etc., but by synchronizing the rectifying plates 10 and changing the angle appropriately, the situation shown in FIG. As shown, the flow direction of the exhaust gas 20 changes in the direction of inclination of the current plate 10, and dust adhering to the reactor inner wall, catalyst layer 3, reinforcing beams, etc. is blown away and removed.

Also, by changing the angle of the current plate 10,
Since the flow path area is relatively reduced compared to the steady state, the gas flow rate increases, and the above-mentioned dust removal effect increases.

In this embodiment, two current plate groups 10a, 1
In order to avoid mutual interference between the rectifying plates 10a and 0b, first, the rectifying plate group 10a is attached to the rotating shaft 11a parallel to the plane of the paper.
(see Fig. 3), and after removing the dust and making it parallel to the gas flow again, the rectifying plate group 10b attached to the rotating shaft 11b perpendicular to the plane of the paper.
These operations are performed periodically or intermittently depending on the state of dust adhesion to remove adhering dust around the reactor.

In particular, in this embodiment, since two groups of rectifying plates are provided, the gas flow can be changed in many directions. Therefore, the attached dust can be efficiently removed.

In this way, by changing the angle of the rectifier plate 10 that is freely displaceable on the upstream side of the catalyst layer 3, the flow direction and flow velocity of the gas can be changed, so that the dust attached inside the reactor can be removed by the gas itself. can do.

In addition, by maintaining each rectifier plate group 10 parallel to the gas flow except when operating for dust removal, the gas flow is rectified, and it is possible to uniformly flow the gas flow into the catalyst layer 3 without causing deviation. Therefore, the denitrification performance as designed can be maintained.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects can be achieved.

(1) Adhering dust can be removed by the gas itself by changing the flow direction and flow velocity of the exhaust gas by changing the angle of the baffle plate provided upstream of the catalyst layer.

(2) Therefore, the steam, air, etc. that were conventionally required for dust removal are no longer required, and the operating costs of the supply equipment to supply them can be eliminated, leading to energy savings in dust removal processing. It can be achieved.

(3) Since it is possible to prevent dust from accumulating on the catalyst layer, it is possible to reduce the catalyst mesh pitch, which reduces the ease of filling the catalyst.
Combined with the reason in paragraph (2), the operating costs of the entire plant can be reduced.

(4) As mentioned above, since dust adhesion and accumulation can be prevented from occurring, an increase in pressure loss can be prevented and long-term continuous stable operation can be achieved.

[Brief explanation of the drawing]

Figure 1 is a schematic longitudinal sectional view showing the denitrification reactor, Figure 2
The figure is a front view showing the first embodiment of the dust removal device according to the present invention, Figures 3 and 4 are perspective views for explaining the operation of the present invention, and Figure 5 is an enlarged front view of the rectifying plate. be. In addition, in the figure, 1 is a denitrification reactor, 22 is a casing, 3 is a catalyst layer, 10 is a rectifier plate, 11 is a rotating shaft,
13 is dust.

Claims (1)

[Scope of utility model registration request] In a denitrification reactor for exhaust gas from a boiler, etc., a rectifying plate is provided on the exhaust gas upstream side of the catalyst layer to change the flow direction and flow velocity of the exhaust gas flowing into the catalyst layer in order to remove dust adhering to the denitrification reactor. A dust removal device for a denitrification reactor, characterized by: