JPH0360525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for preventing gas leakage in adsorption towers used when desulfurizing or desulfurizing and denitrating combustion exhaust gas.

[Prior Art] When performing dry desulfurization or dry desulfurization and denitration of flue gas discharged from various combustion furnaces or combustion furnaces, an adsorption tower filled with a carbonaceous adsorbent such as activated carbon in the form of a moving bed is used. is normally used, and the exhaust gas is desulfurized or desulfurized and denitrated by contacting it with a moving bed of carbonaceous adsorbent in a cross flow.

In the case of the above type of adsorption tower, exhaust gas leaks from the inlet and outlet of the adsorbent, as well as from dust discharge sections provided on the upstream and downstream sides of the moving bed when viewed from the flow direction of the exhaust gas. A rotary valve is installed in this area to prevent this from happening. However, installing a rotary valve alone cannot completely prevent exhaust gas leakage. Since the gas leaking from the adsorption tower is naturally cooled, the moisture in the leaked gas condenses, which impedes the smooth operation of the adsorbent transfer conveyor and its attached equipment. There was also the disadvantage that corrosion occurred in these.

[Means for solving the problems] In order to solve the above-mentioned disadvantages, the present invention has the following features:
This method provides a simple method to prevent gas leakage from an adsorption tower, and its feature is that air heated by waste heat from an exhaust gas generation source is passed through the adsorption tower's adsorbent inlet/outlet area. and blowing into the dust discharge section. To be sure, it has not been conventional practice to blow sealing gas into the adsorbent outlet, inlet, etc. of an adsorption tower for the purpose of preventing gas leakage. Conventional thinking has led to the misconception that an inert gas must be used as the sealing gas, which must also be dehumidified, and for this reason it is not economically viable to blow the sealing gas into the adsorption tower. Traditionally, it was thought that there was no such thing.

In the method of the present invention, it is preferable to use air heated to 80 to 160°C using waste heat from an exhaust gas generation source as the blown air. For example, in the case of a sintering furnace, sintered ore Air is used from the cooler outlet, or in the case of a boiler, from the economizer outlet. The pressure of the blown air can be maintained at about 0 to 50 mmH ₂ O higher than the internal pressure of the adsorption tower. In areas where the bulk density of the adsorbent is sparse, such as the adsorbent inlet of the adsorption tower, it is preferable to increase the blowing amount, for example, the amount equivalent to 1.5 to 3 times the normal gas leak amount. By blowing hot air into the area, gas leaks from the area can be completely blocked.

Next, one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a flow sheet when an iron ore sintering equipment and its exhaust gas treatment equipment are combined.
2 indicates a sintering machine, 2 indicates a dust collector, 3 indicates a sintered ore cooler, and 4 indicates a sintering machine ignition furnace. The exhaust gas from the sintering equipment passes through the dust collector 2 and is then sent to the adsorption tower 9 of the exhaust gas treatment equipment.
is supplied to An adsorbent is supplied to the top of the adsorption tower 9 via a rotary valve 10, and as it flows down the tower as a moving bed, it comes into contact with the exhaust gas in a cross flow to desulfurize and denitrify it. The adsorbent that has reached the bottom of the adsorption tower is transferred to the conveyor 13 via the rotary valve 12.
It is discharged to the top. In addition, dust collection chambers 16 are provided respectively on the upstream and downstream sides of the adsorbent moving bed of the adsorption tower when viewed from the flow direction of the exhaust gas, and the dust collected here is transferred to a screw conveyor at the bottom of the collection chamber. 11 and a rotary valve 12', it is discharged onto a conveyor 13 like the adsorbent. Conveyor 13 transports the adsorbent to the top of regeneration tower 15 . The regeneration tower 15 uses this as a moving bed to regenerate the adsorbent flowing down, and the regenerated adsorbent is discharged from the bottom of the regeneration tower onto the conveyor 14 and circulated to the top of the adsorption tower 9 by the conveyor.

As mentioned above, rotary valves are installed at the adsorbent inlet and outlet sections of the adsorption tower, as well as at the dust discharge section, in order to prevent exhaust gas from leaking from these sections, but this alone cannot completely prevent gas leakage. cannot be prevented. Therefore, in the illustrated embodiment, a part of the air supplied to the sintered ore cooler 3 and heated by heat exchange with the sintered ore is separated into the line 5,
This is blown into the adsorbent inlet, outlet, and dust discharge part to prevent gas leakage from the adsorption tower.

That is, the heated air in line 5 passes through pressure regulating valve 8.
If the temperature of the heated air in line 5 is too high, the amount of cold air supplied from fan 6 and mixed into line 5 is controlled by control valve 7. adjusted. Next, this air is distributed and supplied to the adsorbent inlet, outlet, and dust discharge part of the adsorption tower, and is blown into each part as shown in FIGS. 2 to 4. When the pressure fluctuation inside the adsorption tower is large, it is possible to use a flow rate control valve instead of the pressure control valve 8, or to use both in combination.

Although not shown in the drawings, the blowing of heated air according to the present invention can also be applied to the adsorbent inlet and outlet of a regeneration tower attached to an adsorption tower.
In addition, although the drawing shows an example in which the adsorbent is supplied into the column through a rotary valve and discharged from the column, the present invention can also be applied to an adsorption column that does not use a rotary valve for supplying and discharging the adsorbent. Of course, blowing of heated air can be performed depending on the method.

[Brief explanation of drawings]

Fig. 1 is a flow sheet showing an embodiment of the present invention, Fig. 2 is an enlarged view of the dust discharge section into which heated air is blown, and Fig. 3 is an enlarged view of the adsorbent outlet section into which heated air is blown. , FIG. 4 is an enlarged view of the adsorbent inlet into which heated air is blown. 1: Sintering machine, 2: Dust collector, 3: Sintered ore cooler,
4: Sintering machine ignition furnace, 5: Heating air line for sealing, 6: Cold air fan, 7: Temperature control valve, 8: Pressure control valve, 9: Adsorption tower, 10, 12, 12': Rotary valve, 11: Screw conveyor, 1
3, 14: Conveyor, 15: Regeneration tower, 16: Dust collection room.

Claims (1)

[Claims] 1. A method for preventing gas leakage in an adsorption tower, which comprises blowing air heated by waste heat from an exhaust gas generation source into the adsorbent inlet/outlet and dust discharge part of an adsorption tower used in an exhaust gas treatment device.