JPS60251919A - Gas scrubbing appratus - Google Patents

Abstract

PURPOSE:To reduce operation cost, in a gas scrubbing apparatus, by forming a precipitative separation tank in adjacent relation to a scrubbing solution storage tank and forming the flooding weir from the storage tank to the upper part between both tanks while providing a precipitated catalyst return passage from the lower part of the separation tank to the upper part of the storage tank. CONSTITUTION:Exhaust gas is introduced into a scrubbing tower 2 from a blower 4 to receive gas-liquid contact treatment in a packing material 1 and discharged to the open air while mist therein is removed by a demister 5. Scrubbing water is flowed down to the storage tank 6 provided to the lower part of the scrubbing tower 2 and the pH thereof is measured by a pH meter 8 while an alkali solution 10 is appropriately flowed in on the basis of the pH value to adjust the pH of the scrubbing water. Replenishing water 12 is appropriately added and the scrubbing solution corresponding to the replenished water is flooded from a weir 15 to be flowed into a separation tank 14 and the supernatant solution is flooded to the outside from a weir 21. The catalyst precipitated and accumulated in the separation tank is appropriately returned to the storage tank from a duct 16 by air lift effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for cleaning gas in a cleaning tower using a cleaning liquid containing a catalyst in suspension.

Gas cleaning devices bring specific components in gas into gas-liquid contact through a filler in order to absorb them into a cleaning liquid, and are generally widely used for deodorization, exhaust gas cleaning, and the like. For example, some deodorizing equipment uses an alkaline aqueous solution as the cleaning liquid to clean foul-smelling gas from sources such as human waste treatment towers, absorbs hydrogen sulfide in the gas, and removes it through an alkaline reaction. Some cleaning solutions contain catalysts in a suspended state to increase absorption efficiency.

These are caused by the accumulation of oxidation products of substances absorbed in the cleaning liquid.If the cleaning gas is dry, the water in the cleaning liquid evaporates, concentrating the dissolved substances, causing calcium, magnetic acid, etc. Scales such as cum become easier to generate. For this reason, it is necessary to add make-up water and constantly discharge dissolved substances so as not to increase the concentration rate. Since this discharged cleaning liquid contains catalyst and other suspended matter, various techniques have been used to collect and reuse the catalyst and discharge it as supernatant water free of suspended matter.

An example of the conventional method is as shown in FIG.
The cleaning liquid is jetted down from the spray nozzle 3 at the upper part of the cleaning tower 2, which is equipped with a cleaning tower 2, and the gas to be cleaned is sent from the lower part into the cleaning tower 2 by the blower 4, and the cleaning gas is brought into gas-liquid contact with the cleaning liquid in the packing material 1. After removing the accompanying mist with a demister 5, it is released into the outside air. On the other hand, the cleaning water from the filler 1 flows down to the storage tank 6 at the bottom of the cleaning tower 2 and is circulated to the spray nozzle 3 by the slurry pump 7.

The pH value of the circulating cleaning water is measured by a pH meter 8,
Based on this value, the alkaline concentrate 10 is appropriately flowed into the washing tower 2 by the regulator 9 via the pump 11 to adjust the pH of the washing water.

In addition, in order to prevent malodorous components or oxidation products of malodorous components from accumulating and concentrating in the cleaning solution, a certain amount of make-up water 12
is added, and the added amount of cleaning liquid flows into the adjacent settling tank 14 from the lower opening 13 of the storage tank 6 and overflows from the upper part.

In this conventional example, since the side surface of the sedimentation separation tank 14 is inclined, the flow of the liquid here is slow, and the liquid flows further upward (the flow rate is slow and the suspended catalyst is separated by sedimentation). It is said that

However, the storage tank 6 and the separation tank 14 are connected to the lower opening 13.
Because of this, there is a problem that the catalyst accumulated in the lower part of the storage tank 6 flows into the separation tank 14 together with the flowing water, becomes large in quantity, and flows out together with the overflowing water without settling. That is, there is a problem in that smooth sedimentation and separation cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas cleaning device that can perform smooth sedimentation separation of a catalyst.

In order to achieve this object, in the conventional gas cleaning apparatus described above, a sedimentation separation tank is formed adjacent to the cleaning liquid storage tank in the lower part of the cleaning tower, and a sedimentation separation tank is formed in the upper part between the two tanks from the storage tank. An overflow weir is formed, and a precipitated catalyst return passageway with a pump is provided from the bottom of the separation tank to the top of the storage tank.

With this configuration, gas cleaning is performed by gas-liquid contact as in the conventional case, the cleaning liquid in the storage tank overflows and flows into the sedimentation separation tank, and the supernatant liquid overflows and is discharged to the outside. Sedimentation in the separation tank □The catalyst is returned to the storage tank through the return passage by a pump. During this operation, the upper part of the storage tank does not have much use for holding back the catalyst, and since the washing water in the upper part overflows and flows into the separation tank, the amount of catalyst flowing in is also small.

However, according to the present invention, the amount of catalyst flowing out from the gas scrubbing device is extremely reduced, which has the effect of reducing operating costs.

Embodiments of the present invention will be described below with reference to FIG. 2 of the accompanying drawings. Note that the same reference numerals as above indicate the same items.

As shown in the figure, in the above-mentioned gas cleaning device, an overflow weir 15 is formed at the upper part of the partition between the storage tank 6 and the sedimentation separation tank 14.
．． This allows the cleaning water in two parts of the storage tank 6 to overflow, causing separation (
A tact 16 is provided from the lower part of the tank 14 to the upper part of the storage tank 6, and air can flow into the lower part of the duct 16 from a blower 17 via a solenoid valve 18, and the lifting effect of this air moves the sedimented catalyst in the lower part of the separation tank 14 into the storage tank. Return it to 6.

Air can be supplied from the floor 17 to a diffuser 19 provided at the bottom of the storage tank 6, and the diffusion of air by the diffuser 19 prevents the catalyst from settling and accumulating in the storage tank 6.

If the sedimentation separation tank 14 has a sloped side wall as shown in the drawing, it is advantageous in terms of the catalyst sedimentation effect.

Further, the provision of the current plate 20 in the separation tank 14 has the effect of preventing the cleaning liquid from the storage tank 6 from mixing with the supernatant liquid.

The embodiment is constructed as shown in Fig. 2, and its operation will be explained next.

As in the conventional case, when the gas to be cleaned is sent into the cleaning tower 2 by the blower 4 while the cleaning liquid is jetting down from the spray nozzle 3, the gas to be cleaned passes through the filler 1.
After coming into gas-liquid contact with the cleaning liquid inside, the accompanying mist is removed by a demister 5, and then released to the outside air. On the other hand, the washing water from the filler 1 flows down to the storage tank 6 at the bottom of the washing tower 2.
The slurry pump 7 circulates the slurry to the spray nozzle 3 .

The pT-1 value of the circulating cleaning water is measured by a pT-1 total 8, and based on the value, the regulator 9 flows the alkaline concentrated liquid 10 or the pump 11 into the cleaning tower 2 as appropriate for cleaning. The pH of the water is adjusted.

In addition, make-up water 12 is suspended and added at the appropriate time to adjust the concentration of the washing water, and the added amount of washing liquid overflows from the weir 15 and flows into the separation tank 14, and the supernatant liquid flows from the weir 21 above it. overflows to the outside. During this operation, the amount of catalyst in the upper part of the storage tank 6 is small, and the washing water in the upper part flows into the separation tank 14 by overflowing, so the amount of catalyst flowing in is also small.

The catalyst deposited in the separation tank 14 is returned to the storage tank 6 through the tact 16 as needed or periodically due to the air lift effect. Normally, the blower 17 can be an existing blower installed in the processing equipment including this gas cleaning device, and in this respect, return using an air lift is advantageous.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional gas cleaning device, and FIG. 2 is a schematic diagram of an embodiment of the gas cleaning device of the present invention. 1...Filling material, 2...Washing tower, 6...Storage tank, 14
... Sedimentation tank, 15... Weir, 16... Duct Patent applicant Kubota Iron Works Co., Ltd. Figure 1 Cleaning gas ↑ Figure 2 Cleaning gas ↑

Claims (1)

[Scope of Claims] ([) An apparatus for performing gas cleaning in a cleaning tower using a cleaning liquid containing a catalyst in a suspended state, wherein a sedimentation separation tank is formed adjacent to a cleaning liquid storage tank at a lower part of the cleaning tower; A gas cleaning device characterized in that an overflow weir from the storage tank is formed in the upper part between the two tanks, and a precipitated catalyst return passage with a pump interposed from the lower part of the separation tank to the upper part of the storage tank is provided. (2) The gas cleaning device according to claim (1), wherein the pump is of an air lift type.