JPH02227113A - Gas sealing method in two-step type dry desulfurization equipment - Google Patents

Abstract

PURPOSE:To prevent particles of small diameter from being accumulated to the lower part of a denitrification tower by providing the conveyors for discharging an adsorbent which has been blown off to the outside lowermost parts of the outlet louvers of a desulfurization tower and the denitrification tower. CONSTITUTION:A denitrification tower 7 is placed to the upper part of a desulfurization tower 6 via a material sealing part 10. The conveyors 17 for discharging an adsorbent 18 are provided which has been blown off to the outside lowermost parts of the outlet louvers 4 of the desulfurization tower 6 and the denitrification tower 7. The adsorbent recovered by the conveyors 7 is returned to an adsorbent circulating and transferring system and can be reutilized. In other words, even when the amount of particles having small diameter is increased which are contained in the granular adsorbent in the lower part of the denitrification tower, the increase of pressure drop of the gas to be treated can be prevented which is passed through the granular adsorbent layer. As a result, the problems such as lowering of the amount of the gas to be treated, rise in operating cost and blowout of the granular adsorbent from the louver of a gas outlet side can be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gas sealing method for a two-stage dry desulfurization apparatus.

(Prior art) Two-stage dry desulfurization and denitrification equipment having a desulfurization tower and a denitrification tower include a desulfurization tower and denitrification tower juxtaposed type as shown in Figure 5, and a denitrification tower mounted type as shown in Figure 6. It has been known. Since the side-by-side type has gas seal valves 2 above and below each tower, the gas to be treated 1 will not leak from the desulfurization tower 6 to the denitrification tower 7 through the adsorbent path. Since there is no mechanism for gas sealing between the lower part and the upper part of the desulfurization tower 6, the seal between them relies on a material seal.

In addition, since the side-by-side type as shown in FIG. 5 spreads laterally, the installation space becomes large, and a large number of conveyors 5 and the like are required to circulate the adsorbent. On the other hand, the mounted type shown in Figure 6 has a more compact structure.

Since there is a pressure gradient from the upper part of the desulfurization tower 6 to the lower part of the denitrification tower 7, it is impossible to completely prevent gas leakage during this period.

(Problems to be Solved by the Invention) As shown in FIG. 6, in a moving bed type dry desulfurization and denitrification device in which a denitrification tower 7 is mounted on the desulfurization tower 6, a granular adsorbent (for example, activated carbon ) When the amount of small-diameter particles (powdered activated carbon, dust, etc.) contained in the granular adsorbent layer increases, the pressure loss of the process gas passing through the granular adsorbent layer increases. This causes problems such as a decrease in the amount of gas to be processed, an increase in operating costs, and blowing of particulate adsorbent from the louver on the gas outlet side.

In view of these problems, it is an object of the present invention to provide a structure that can prevent small-diameter particles from accumulating in the lower part of a denitrification tower.

(Means for solving problems by the invention) In a moving bed type dry desulfurization and denitrification device in which a denitrification tower is mounted on the upper part of the desulfurization tower via a material seal part, an adsorbent blown out to the outermost bottom part of the desulfurization tower and the outlet louver of the denitrification tower A conveyor was provided to discharge the adsorbent, and the adsorbent collected by the conveyor was returned to the adsorbent circulation transfer system so that it could be reused.

Further, a slit and a slit plate extending outward from the slit and having an inclination smaller than the repose angle of the adsorbent were provided in the lowermost louver portion of the denitrification tower outlet louver.

(Example) An explanation will be given based on FIGS. 1 to 4. FIG. 1 shows a mounted two-stage dry desulfurization and denitrification apparatus similar to FIG. 6, and the gas to be treated 1 flows into a desulfurization tower 6 on the lower side.

Adsorbent layer 1 filled between inlet louver 3 and outlet louver 4
9, the treated gas 9 passes through the adsorbent layer 19' filled between the inlet louver 3 and the outlet louver 4 again in the upper denitrification tower 7.
and is discharged.

Now, with such a configuration, it was thought that the adsorbent would not fly out from the outlet louver 4. However, in reality, adsorbents of sufficient size that can still be used may also fly out, mixed in with adsorbents of small particle size.

This is undesirable because it accumulates at the outer lower part of the outlet louver 4 during long-term operation and not only obstructs the gas flow but also increases the amount of adsorbent consumed.

Therefore, in the present invention, a conveyor 17 is provided at the lower part of the outlet side of the outlet louver 4 to collect the adsorbent and return it to the adsorbent transfer system.

The adsorbent collected on the conveyor 17 is passed through a sieve (not shown) or directly returned to the adsorbent transfer system, passed through a sieve in the transfer system to remove powder, and the usable amount is reused. .

In particular, in the case of the mounted type, small particles 12 blown up by leak gas 11 from the upper part of the desulfurization tower 6 through the material seal part 10 are placed at the bottom of the outlet louver 4 of the denitrification tower 7 as shown in FIG. As a result, the concentration of small particle size particles 12 increases extremely.
The ventilation resistance at the bottom of the denitrification tower increases, and the pressure drop across the denitrification tower increases.

As shown by reference numeral 13 outside the lower part of the louver 4, a large amount of adsorbent is instantly blown out, and the plant becomes inoperable.

In order to prevent the accumulation of small particles 12 blown up by the leak gas 11, the present invention provides a slit 15 at the lowest stage of the outlet louver 4 of the denitrification tower 7 and a slit plate 16 extending outward from the slit 15. Established.

The angle of inclination of the slit plate 16 is smaller than the angle of repose of the adsorbent;
This provides an angle that prevents the adsorbent from falling by itself when the adsorbent transfer is stopped or there is no gas flow.

However, when the adsorbent is transferred, a small amount of the adsorbent is pushed outward due to the dynamic pressure of the powder pressure generated during the movement. A small amount of adsorbent is also pushed out by the gas flow. This extruded adsorbent is the accumulated small particle size 12
is removed from the system to prevent accumulation. At this time, if the height of the slit 15 or the angle connecting the upper end of the slit and the tip of the slit plate 16 can be changed, the amount extracted from the slit 15 can be adjusted.

Further, as shown in FIG. 2, it is also possible to receive the adsorbent pushed out from the slit 15 at an angle of repose so that only the amount discharged by the conveyor 17 comes out from the slit 15.

(Effects) A conveyor for discharging the blown out adsorbent was provided at the outermost bottom of the exit louver of the desulfurization tower and the denitrification tower, and the adsorbent recovered by this conveyor was returned to the adsorbent circulation transfer system. Therefore, even if the amount of small-diameter particles contained in the granular adsorbent in the lower part of the denitrification tower increases, it is possible to prevent the pressure loss of the process gas passing through the granular adsorbent layer from increasing.
As a result, problems such as a decrease in the amount of gas to be processed, an increase in operating costs, and the blowing out of particulate adsorbent from the louver on the gas outlet side could be solved.

Further, a slit and a slit plate extending outward from the slit and having an inclination smaller than the repose angle of the adsorbent were provided in the lowermost louver portion of the denitrification tower outlet louver.

This also makes it possible to prevent the accumulation of small-sized particles blown up by leak gas.

[Brief explanation of the drawing]

Figure 1 is an overall view of the parallel two-stage dry desulfurization and denitrification equipment. Figure 2 is an overall diagram of the on-board two-stage dry desulfurization and denitrification equipment. Figure 3 is an enlarged view of the mounted material seal. FIG. 4 is a sectional view of the discharging machine of the present invention. FIG. 5 is a sectional view showing the exit louver slit of the present invention. FIG. 6 is a front view of the exit louver slit portion of the present invention. FIG. 7 is an enlarged view of the outlet louver slit portion of the present invention. 1 Gas to be treated (exhaust gas) 2 Gas seal valve 3 Population louver 4 Outlet louver 5 Conveyor 6 Desulfurization tower 7 Denitration tower 8 Desorption tower 9 Processed gas 10 Material seal part 11 Leak gas 12 Small particle size particles 13 Blowing adsorbent 14 Circulation state of small particle size 15 Exit louver slit 16 Exit louver slit plate 17 Adsorbent 19 spilled from the roller of conveyor 18 Adsorbent layer and above 1st Diagram size 0

Claims (1)

[Scope of Claims] 1) In a moving bed type dry desulfurization and denitrification equipment in which a denitrification tower is mounted on the upper part of the desulfurization tower via a material seal, the adsorbent blown out to the outermost bottom part of the desulfurization tower and the exit louver of the denitration tower A gas sealing method for a two-stage dry desulfurization apparatus, characterized in that a conveyor is provided for discharging the adsorbent, and the adsorbent recovered by the conveyor is returned to the adsorbent circulation transfer system so that it can be reused. 2) The two-stage system according to claim 1, wherein the lowermost louver of the denitrification tower outlet louver is provided with a slit and a slit plate extending outward from the slit and having an inclination smaller than the angle of repose of the adsorbent. Gas sealing method for dry desulfurization equipment.