BACKGROUND OF THE INVENTION

The present invention relates to an improvement on a solid-gas contact reactor for dirty gas such as exhaust gas of a sintering furnace or a coking oven using coal or heavy oil and, more particularly, to such reactor of upright type in which the troubles due to a piling up of dust are eliminated.

The conventional solid-gas contact reactor is shown in FIGS. 1A to 1D. As will be clear from these figures, it is composed of a plurality of packages of catalyst layers each composed of a plurality of relatively short, identical honeycomb catalysts 1 stacked in a frame structure 2. The plurality of the packages of catalyst layers are mounted on a support base 3 provided for each stage of the reactor. Although the cross sectional shape of each gas passage of the honeycomb catalyst is shown as being reactangular in FIG. 1A, it may be hexagonal or triangular.

With this structure, a gas flow 7 in the down stream side of the support base 3 tends to drift. In addition to this, since the flow rate of the gas is relatively low, there may be vortices in a peripheral area of a lower surface of the support base 3 adjacent to a wall 6 of the reactor and dust 4 may pile up around the peripheral area with time, as shown in FIG. 1D. This tendency is enhanced when the dust is viscous.

When the accumulation of the dust 4 exceeds a certain level, it tends to fall down into the gas passages 5 and the end faces of the catalyst layers in the subsequent stage by gravity or other externally applied vibrations etc., resulting in a substantial pressure loss in the reactor and renders impossible a continuous, long period of operation and further, the performance of the catalyst itself is degraded.

Further, dust accumulates on areas a between the adjacent frame structures 2 and areas b between the frame structure 2 and the reactor wall 6 on the upstream side of the gas flow. The dust ends to fall downwardly due to external forces etc. and clog the gas passages 5 of the catalyst layers thereof, causing the same problems to occur as mentioned previously concerning the down stream side.

SUMMARY OF THE INVENTION

The present invention is intended to resolve the above-mentioned problems inherent in the conventional reactor and an object of the present invention is to provide an improvement on the conventional solid-gas contact reactor for dirty exhaust gas, which is featured by a first dust-proof plate means provided on contact areas between a lower surface of a support base for support packages of catalyst layers in each stage and a reactor wall so that the first dust-proof plate means makes an angle equal to or larger than the rest angle of dust in the exhaust gas with respect to the support base and second dust-proof plate means provided on contact areas between adjacent ones of the packages of catalyst layers in each stage and contact areas between the reactor wall and frames of the packages of catalyst layers so that the second dust-proof plate means forms the same angle with respect to the frame structure of the reactor.

BRIEF DESCRIPTION OF THE DRAWING

Other objects and features of the present invention will become clear from the following description of the preferred embodiments of the present invention with reference to the accompanying drawings through which identical portions are depicted by the same reference numerals, in which:

FIGS. 1A to 1D show the conventional solid-gas contact reactor in which FIG. 1A is a unit of honeycomb layers, FIG. 1B is a packages of catalyst layers, FIG. 1C is a plurality of packages of catalyst layers mounted in stack on the support bases of the reactor frame and FIG. 1D illustrates the dust accumulation in the reactor.

FIGS. 2A to 2C show an embodiment of the present invention in which FIG. 2A illustrates the downstream side portion of the embodiment, FIG. 2B is a perspective view of FIG. 2A and FIG. 2C illustrates the upstream side portion of the embodiment; and

FIGS. 3A and 3B show dust-proof plate means adapted to be used in the upstream side.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Firstly, to the downstream side of the packages of catalyst layers on the support base 3 with respect to the gas flow 7, a first dust-proof plate means is provided on the wall 6. The support base has openings therethrough aligned with the edges of the frame structure defining the flow path through each package of catalyst layers. The openings have sides arranged generally parallel to and spaced closely from the inside surface of the wall forming the flow path through the reactor. The first dust-proof plate means comprises a plate member 8 bridging between the wall 6 and the lower surface of the support base 3 as shown in FIGS. 2A and 2B. The angle .theta. between the plate member 8 and the support base 3 is selected such that it is not less than the rest angle (45.degree.) of dust in the exhaust gas and is less than 90.degree.. It may be possible that the plate member 8 is formed integrally with the support base 3. It is preferable that the plate member 8 has flat and smooth surfaces.

In the upstream side of the packages of catalyst layers, second dust-proof plate means 9 is provided as shown in FIG. 2C. The second dust-proof plate means 9 comprises a dust-proof plate member 9.sub.1 for contact areas a, note FIG. 1C, between the adjacent packages of catalyst layers and a dust-proof plate member 9.sub.2 for the contact areas b between the packages of catalyst layers and the reactor wall 6. The plate members 9.sub.1 and 9.sub.2 have the structures shown in FIGS. 3A and 3B, respectively. That is the slanting angle .theta. thereof is generally selected as being equal to or larger than the rest angle (45.degree.) but smaller than 90.degree..

With the above-mentioned structure, the accumulation of dust on the downstream side of the support base and on the upper portion of the frame structure facing toward the inlet side of the catalyst layers is minimized. Therefore, clogging of the gas passages thereof and the adverse effects on the catalyst performance are eliminated, affording a long period, continuous operation of the reactor to become possible. This effect is very important practically.

Although in the above mentioned embodiment, the gas flows vertically downwardly, the present invention is also applicable to gas flow in the opposite direction.