JPS6341615B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a solid-gas catalytic reaction that prevents dust from adhering to the filling material in a gas parallel flow type solid-gas catalytic reactor that processes dirty exhaust gas such as denitrification and deflow of coal-fired boiler exhaust gas. Regarding equipment.

One of the problems with solid-gas contact reactors for treating dirty exhaust gas is clogging of the packed bed with dust.

As a countermeasure to this problem, parallel flow gas reactors using grid-like or hunk-like packings have been proposed.
(Example: Japanese Patent Application No. 51-082697) In this method, since the catalyst surface is arranged parallel to the gas flow direction, there is less dust collision with the catalyst surface, and therefore there is almost no dust adhesion, so it is so-called dust-free. It is a type of solid-gas contact device.

However, since the dust collides perpendicularly with the end face of the packing into which the exhaust gas flows, depending on the adhesion of the exhaust gas dust, some of the dust may adhere or
It may accumulate and become partially occluded (Figure 4).
If left as it is, the performance of the processing equipment will deteriorate and the operation of the smoke source equipment will be affected, so it is necessary to periodically brush off the dust.

Currently, a method of blowing steam or air (hereinafter referred to as soot blowing method) is being considered as a means of blowing off adhering dust during process operation, but although this method is reliable in removing dust, In a solid-gas contact reactor that processes a large volume of exhaust gas such as exhaust gas, a large amount of air or steam is required to soot-blow the entire surface of the gas inlet, which has a huge cross section, making it uneconomical and the equipment complicated. shortcomings have been pointed out.

The present invention was made to improve the conventional drawbacks, and as a result of investigating the properties of dust deposits on the end face of the packing for various exhaust gases, it was found that in order to remove the deposits, a particularly strong soot broker is not used. By installing a baffle plate on the gas upstream side of the adhering end face and appropriately disturbing the gas flow flowing into the filling end downstream of the baffle plate, adhesion of dust can be almost eliminated.
It has been discovered that deposits can also be removed.

Hereinafter, details of the present invention will be explained using combustion exhaust gas as an example with reference to FIGS. 1 and 2.

In FIG. 1, 1 is combustion gas flowing in a vertical direction, 2 is a packed bed, and 3 is combustion gas that has passed through the packed bed and has been purified by a solid-gas reaction.

As shown in detail in FIG. 3, the packed bed is made of a lattice-shaped, honeycomb-shaped, or other type of packing having gas ventilation holes, and is generally packaged in a plurality of pieces and supported by a duct on the outer wall of the packing.

A feature of the present invention is that a baffle plate 4 that causes gas disturbance is installed on the gas upstream side of the packed bed.

A plurality of these baffle plates are fixed on a support body 5 that can be moved left and right. In addition, in FIGS. 1 and 2, the support 5 has a mechanism that automatically reciprocates in the length direction of the support, so that the dust deposits 6 shown in FIG. 1 can be thoroughly removed. is now possible.

In the packed layer 2, Nox and SOx in the combustion gas
reacts with the reducing agent previously supplied,
Since the gas is removed in a solid-gas contact manner, such as by being adsorbed by the packing, the gas that has passed through the packed bed 2 is discharged outside the system as clean gas 3, as described above.

On the other hand, part of the dust contained in the exhaust gas adheres to the end face of the inlet of the packed bed and grows as dust deposits 6.

As shown in FIG. 4, this form of dust adhesion is such that the dust adhesion 6 tends to grow along the end face of the packed bed in the gas flow direction 1. 2
a is a side view of the packed bed; However, since turbulence 7 such as eddy currents and drifted flows occur downstream of the baffle plate, the direction of gas flow is not constant, and the adhesion of dust does not occur due to the re-scattering effect of the adhering dust due to the flow that occurs from side to side. Since this baffle plate covers the entire end surface of the filling layer in the range in which the support body 5 moves from side to side, it is possible to prevent dust from adhering to the entire end surface of the filling layer.

FIG. 5 shows another embodiment of the baffle plate. A is a long, rectangular steel plate, and B is the steel plate in A installed at an angle. C is a combination of two rectangles as shown in the figure, d is a triangular shape, and e is a double combination of tubes. Various baffle plates are effective.

This dust adhesion prevention effect becomes better as the gas flow rate increases. 4
It was effective in the range of ~10 m/sec. Moreover, it was particularly effective when the distance between the baffle plate and the end face of the packed bed was 100 to 600 mm.

Next, in the case of a tubular baffle plate such as a triangular or round shape, a nozzle 8 is provided in the direction of the filling of the tube as shown in FIG.
By communicating with the suit blower, it can also be used as a suit blowing device.

In this case as well, it is normally used as a dust adhesion prevention device using a baffle plate effect, and is used intermittently when it is desirable to remove dust relatively cleanly, such as before a long-term shutdown.

As described above, this dust adhesion prevention operation is performed during process operation, so it can be applied to fixed bed reactors, and compared to the soot blowing method, it is possible to
There is no need to introduce air or other air from outside, making it mechanically simple and economical.

Furthermore, even when used in the soot blowing method, there is no need for soot blowing all the time, so there are economical effects such as less air and the like being used.

As described above, the solid-gas contact reaction apparatus of the present invention can prevent the inlet portion of the packed bed from being clogged with adhering substances such as dust with reliable effect and economy, and has excellent practical value.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment in which the present invention is applied to combustion exhaust gas, Fig. 2 is a perspective view of the main parts thereof, Fig. 3 is a perspective view showing an example of a filler applied to the present invention, Fig. 4 The figure is an explanatory diagram showing the growth of deposits on the end face of the filling, Figure 5 is a side view of an embodiment of the support and baffle plate that constitute the main parts of the present invention, and Figure 6 is a soot blow nozzle attached to the baffle plate. FIG. 2 is a schematic diagram of an example in which 1... Combustion gas, 2... Solid gas contact packed bed, 3...
...Clean gas, 4...Baffle plate, 5...Support, 6...
...Dust deposits, 7...Gas disturbances such as vortices and drifts, 8...Soot blow nozzle, 9...Pressure gas from outside.

Claims (1)

[Claims] 1. In a solid-gas contact reactor, a movable gas baffle plate is installed on the gas upstream side of the packing, and turbulence in the gas flow such as a gas vortex or drift that reaches the end face of the packing from the downstream of the baffle plate is generated, A solid-gas contact reaction device characterized by preventing dust from adhering to an end face of a gas inlet of a gas.