JPH08266862A - Nitrogen oxide adsorbing and removing device - Google Patents

Abstract

PURPOSE: To prevent the drift at the time when regenerated gases pass the adsorbents of a device housed with adsorptive materials so as to partition the inside of a hermetic reaction vessel to a diffusion zone and a collection zone by installing current rectifying members at the corners where the relative wall surfaces of the adsorptive materials in the diffusion zone and the relative wall surfaces of a regenerated gas outlet intersect. CONSTITUTION: This NOx adsorbing and removing device for adsorbing and removing the low-concn. NOx included in a large amt. of ventilation gases in various kinds of tunnels has a reactor 11 and the adsorbents 12 packed in this reactor 11. The adsorbents 12 are arranged in about the middle of the height in the reactor 11, by which the inside of the reactor 11 is divided to the diffusion zone 43 communicated with the a treating gas inlet 31 and a regenerated gas outlet 36 and the collection zone 44 communicating with a treated gas outlet 32 and a regenerated gas inlet 35. The right current rectifying members 51 are built up in the corner parts where the bottom walls 21 and right side walls 24 in the diffusion zone 43 intersect in such a manner that these parts are rounded. In addition, the left current rectifying members 52 are built up in the parts on the left side of the treated gas inlet of the bottom walls 21.

Description

Detailed Description of the Invention

[0001]

This invention relates to various road tunnels,
A large amount of ventilation gas (100,000 m3) in various tunnels such as mountain tunnels, subsea tunnels, underground roads, and roads with shelters.
/ h or more), and a NOx adsorption / removal device for adsorbing and removing a low concentration of NOx (nitrogen oxide).

[0002]

2. Description of the Related Art As this type of NOx adsorption / removal device,
The so-called cone type is a horizontal cylindrical closed reactor having tapered portions at both ends, and an adsorption filled in the reactor so as to divide it into a diffusion zone and a collection zone in the length direction. Equipped with a material, in the reactor,
A processing gas inlet communicating with the diffusion zone and facing the adsorbent and a processing gas outlet communicating with the collection zone and facing the adsorbent are provided, with an inlet pipe at the processing gas inlet and an exhaust pipe at the processing gas outlet. It is known that they are connected to each other, and a discharge gas is provided with a regeneration gas inlet and an introduction pipe is provided with a regeneration gas outlet.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the Ox adsorption / removal device, if the size of the diffusion zone and the collection zone is set to be large enough to diffuse the regenerated gas in the diffusion zone and the collection zone in preparation for the regeneration of the adsorbent, the adsorbent will pass through. However, if the size of the diffusion zone and the collection zone is small, the regeneration gas concentrates only on the part of the entire adsorbent that faces the process gas inlet and outlet. As a result, the deviation of the regeneration gas becomes large. Therefore, the diffusion zone and the collection zone tend to be set large, and then the entire reactor becomes large, and it is difficult to install the reactor in a limited space such as an underground space.

An object of the present invention is to provide a NOx adsorption / removal device which solves the above problems, reduces the pressure loss of the regeneration gas passing through the reactor, and saves space.

[0005]

A NOx adsorption / removal apparatus according to the present invention comprises a closed reactor and an adsorbent filled in the reactor so as to divide the reactor into a diffusion zone and a collection zone. In the NOx adsorption / removal device, the reactor is provided with a processing gas inlet communicating with the diffusion zone and facing the adsorbent and a processing gas outlet communicating with the collection zone and facing the adsorbent. A regeneration gas inlet communicating with the collection zone and orthogonal to the processing gas outlet and a regeneration gas outlet communicating with the diffusion zone and orthogonal to the processing gas inlet are provided, and the vertical and horizontal cross sections of the reactor are , Both of which are formed in a rectangular shape, and the corners of the diffusion zone where the wall surface facing the adsorbent and the wall surface facing the regeneration gas outlet intersect are rounded. It is characterized in that the member is piled.

[0006]

In the NOx adsorption / removal device according to the present invention, the reactor is provided with a regeneration gas inlet which communicates with the collection zone and is orthogonal to the treatment gas outlet, and a regeneration gas which is communicated with the diffusion zone and orthogonal to the treatment gas inlet. Since the outlet is provided, the regenerated gas introduced into the collection zone from the inlet is
In the collecting zone, it flows in such a direction to the surface of the adsorbent to be diffused, passes through the whole of the adsorbent, and then flows along the surface of the adsorbent in the diffusion zone and exits from the outlet.

Further, since the vertical cross section and the horizontal cross section of the reactor are both formed in a rectangular shape, the maximum gas passage area is secured in the minimum space.

Further, in the corner portion where the wall surface facing the adsorbent and the wall surface facing the regeneration gas outlet intersect in the diffusion zone,
Since the rectifying member is provided so as to be rounded, turbulent flow is prevented from occurring in the diffusion zone.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, the NOx adsorption / removal apparatus includes a reactor 11 and an adsorbent 12 filled in the reactor 11.
It has and.

The reactor 11 is a box-shaped hermetically-closed reactor having a vertical cross section and a horizontal cross section, and has a bottom wall 21 and a top wall.
It has 22 and left and right side walls 23, 24.

The bottom wall 21 has a downwardly projecting rectangular tubular processing gas inlet 31.
However, the top wall 22 is provided with an upward projecting rectangular tubular processing gas outlet 32, respectively. Dampers 33 and 34 are provided in the inlet 31 and the outlet 32, respectively. A left-side protruding rectangular tubular regeneration gas inlet 35 is provided above the center of the left side wall 23.
However, the left-side protruding rectangular tubular regeneration gas outlets 36 are respectively provided on the lower side thereof. Dampers 37 and 38 are also provided at the open ends of the inlet 35 and the outlet 36, respectively.

The adsorbent 12 is arranged in the middle of the height in the reactor 11. As a result, in the reactor 11, a diffusion zone communicated with the process gas inlet 31 and the regeneration gas outlet 36.
43 and a collection zone 44 in communication with the process gas outlet 32 and the regeneration gas inlet 35, respectively.

At the corner where the bottom wall 21 and the right side wall 24 intersect in the diffusion zone 43, a right rectifying member 51 having a substantially triangular cross section is provided so as to be rounded. Further, a left flow straightening member 52 having a substantially arcuate cross section is provided in a portion of the bottom wall 21 on the left side of the processing gas inlet.

The processing gas is supplied from the processing gas inlet 31 to the reactor 11
While passing through the adsorbent 12, the target components such as nitrogen oxides contained in the processing gas are adsorbed and removed, and then discharged from the processing gas outlet 32 to the outside of the reactor 11.

When the concentration of the treated gas component exceeds the reference value or when the gas passage time reaches the reference time, the adsorbent 12 is regenerated.

Regeneration of the adsorbent 12 is carried out by introducing a regeneration gas into the reactor 11 through the regeneration gas inlet 35. Hot air at 200 to 350 ° C. is used as the regeneration gas. The regeneration gas introduced into the reactor 11 passes through the adsorbent 12 in the direction opposite to the flow of the processing gas, and during this time, the adsorbent 12
The adsorbent 12 is regenerated by desorbing the target component adsorbed on the. The regeneration gas that has passed through the adsorbent 12 is discharged from the regeneration gas outlet 36 to the outside of the reactor 11. The discharged regenerated gas is passed through an ammonia-added SCR denitration catalyst (not shown) to remove the target component, and then introduced into the reactor 11 through the regenerated gas inlet 35 and circulated and reused.

In order to effectively regenerate the adsorbent 12, it is necessary to minimize the nonuniform flow of the regeneration gas when passing through the adsorbent 12 so that the regeneration gas can flow uniformly. If the uneven flow is large, the temperature rise of the adsorbent 12 may fluctuate, and the regenerated residue may occur, so that the regeneration may not be performed uniformly.To avoid this, it is necessary to use more regeneration gas than necessary. It is uneconomical. In addition, when the regenerated gas is turbulent due to the uneven flow, the pressure loss is increased, and the operating cost of the regenerated gas blower is also increased.

If, as shown in FIG.
If there is no 51 and left rectifying member 52, when the regeneration gas introduced into the reactor 11 passes through the adsorbent 12 and flows into the diffusion zone 43, the bottom wall 21 of the reactor 11 and the left and right side walls 23, 24 intersect. A swirl may occur in the left and right corners, but this is prevented by both the flow regulating members 51, 52.

[0020]

According to the present invention, the regenerated gas introduced from the inlet into the collecting zone flows in such a direction to the surface of the adsorbent in the collecting zone to be diffused, and after passing through the whole of the adsorbent, is diffused. In the zone, it flows along the surface of the adsorbent and exits from the outlet, so it is possible to prevent uneven flow of the regeneration gas when passing through the adsorbent.

Further, since the maximum gas passage area is secured in the minimum space, the reactor can be made compact, and installation in a limited space is possible.

Further, since turbulent flow is prevented from being generated in the diffusion zone, the pressure loss of the regeneration gas can be reduced.

[Brief description of drawings]

1 is a vertical cross-sectional view of a device according to the present invention.

FIG. 2 is a vertical longitudinal sectional view corresponding to FIG. 1 of a device showing a comparative example of the present invention.

[Explanation of symbols]

 11 Reactor 12 Adsorbent 31 Processing gas inlet 32 Processing gas outlet 35 Regeneration gas inlet 36 Regeneration gas outlet 43 Diffusion zone 44 Collection zone 51 Rectifying member

Claims (1)

[Claims] 1. The reactor 11 is provided with a closed reactor 11 and an adsorbent 12 which is filled inside the reactor 11 so as to partition the diffusion zone 43 and the collection zone 44. Process gas inlet communicating with zone 43 and facing adsorbent 12
In the NOx adsorption / removal device that is provided with a processing gas outlet 32 that communicates with 31 and the collection zone 44 and faces the adsorbent 12, the reactor 11 communicates with the collection zone 44 and the processing gas outlet 32.
There is provided a regeneration gas inlet 35 that is orthogonal to the above and a regeneration gas outlet 36 that is in communication with the diffusion zone 43 and is orthogonal to the processing gas inlet 31, and both the vertical cross section and the horizontal cross section of the reactor 11 are Formed in shape, diffusion zone
A NOx adsorption / removal device characterized in that a rectifying member 51 is provided at a corner where a wall surface facing the adsorbent 12 of 43 and a wall surface facing the regeneration gas outlet 36 are rounded.