JP4742926B2 - Exhaust gas treatment equipment - Google Patents

Description

The present invention relates to an exhaust gas treatment facility for treating exhaust gas containing SO _x or the like generated when a sintered ore is produced.

Many types of exhaust gas, such as various types of boiler exhaust gas, incinerator exhaust gas such as garbage, and exhaust gas generated from a steel mill sintering machine, include dust, sulfur oxide (SO _X ), nitrogen oxide (NO _X ), heavy metals, Contains harmful substances such as dioxins. As a treatment method for these exhaust gases, exhaust gases are introduced into a packed bed filled with granular carbonaceous adsorbents, the exhaust gases are brought into contact with the adsorbents to remove harmful substances, and the used carbonaceous adsorbents are heated and regenerated. Then, an adsorption technique using a packed bed that is circulated and used is known (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

In the adsorption technology using a packed bed, a packed bed is formed with a moving bed reactor or the like packed so as to move a carbonaceous adsorbent such as activated carbon or activated coke from the upper side to the lower side, and packed when exhaust gas passes through the packed bed. Adsorb toxic substances to the layer. In this method, for example, SO _x in the exhaust gas is adsorbed and removed as sulfuric acid on the carbonaceous adsorbent. About dioxin, besides adsorbing to the carbonaceous adsorbent, particulate matter is also removed as dust.

  Since the sulfuric acid and the like are gradually accumulated in the carbonaceous adsorbent due to contact with the exhaust gas, and the desulfurization activity and denitration activity of the carbonaceous adsorbent decrease with time, it is necessary to regenerate the carbonaceous adsorbent. The carbonaceous adsorbent whose activity is temporarily reduced is conveyed to the top of a moving bed type regenerator, for example, and supplied into the regenerator through a supply valve. It is heated and regenerated in the process of moving to the lower part in the regenerator.

In this regeneration treatment, a large amount of SO ₂ , N ₂ , CO _2, and H ₂ O is generated by decomposition of sulfuric acid or the like adsorbed on the carbonaceous adsorbent. The carbonaceous adsorbent thus heated and regenerated is cooled, discharged from the bottom of the regenerator, supplied again to the top of a moving bed reactor or the like and reused.

  As described above, when the carbonaceous adsorbent is recycled, a part of the adsorbent is gradually pulverized. The powdered adsorbent is difficult to reuse in the packed bed, and the powdered adsorbent is separated and removed by wind sorting or sieving after regeneration. At the same time, the adsorbed dust is also removed.

If the exhaust gas treatment is performed using the adsorption technique using the packed bed as described above, the exhaust gas treatment can be efficiently performed by repeatedly using the carbonaceous adsorbent.
JP 2003-53135 A JP 2000-233112 A JP-A-8-131777

  However, when exhaust gas generated from a sintering machine for producing sintered ore, which is a raw material for iron making, is treated with exhaust gas using a carbonaceous adsorbent, the ventilation resistance of the packed bed gradually increases. is there.

  As the carbonaceous adsorbent is repeatedly used, the amount of dust that cannot be separated during sieving and remains attached to the carbonaceous adsorbent increases, and the activated carbon gradually wears to reduce the particle size. In addition, the ventilation resistance of the packed layer increases. When the ventilation resistance of a part of the packed bed increases, the exhaust gas flows through a portion with a low ventilation resistance, the flow velocity of the portion increases, the harmful substance removal rate decreases, and the processing efficiency decreases. When the ventilation resistance of the packed bed increases as a whole, it becomes difficult to introduce the exhaust gas into the packed bed, and it becomes difficult to perform the exhaust gas treatment operation. In order to increase the ventilation resistance, for example, the residence time in the packed bed of the carbonaceous adsorbent is shortened to increase the circulation rate, that is, the packed bed passage time of the carbonaceous adsorbent is relatively shortened with respect to the regeneration time. By increasing the dust recovery rate, it is possible to temporarily suppress the increase in ventilation resistance. However, finally, the exhaust gas treatment is stopped and only the carbonaceous adsorbent regeneration process is performed.

  Specifically, when the exhaust gas treatment facility is operated for about two weeks, the ventilation resistance of the packed bed increases, and it becomes necessary to perform a cleaning operation for stopping the exhaust gas treatment and performing only the regeneration treatment for about five days. However, since the exhaust gas treatment is stopped, it is necessary to perform treatment using other equipment, which is inefficient. Such a problem that the ventilation resistance of the packed bed increases and the continuous operation of the facility becomes difficult cannot be dealt with by the conventional techniques described in Patent Documents 1 to 3 and the like.

  Accordingly, the object of the present invention is to solve such problems of the prior art, and to perform exhaust gas treatment that occurs when a sintered ore is produced with a packed bed formed of an adsorbent by using the adsorbent in a circulating manner. An object of the present invention is to provide an exhaust gas treatment facility that reduces the degree of increase in ventilation resistance and enables a stable operation of exhaust gas treatment for a long period of time.

The features of the present invention for solving such problems are as follows.
(1) In order to treat the exhaust gas generated when producing the sintered ore, the adsorbent for removing harmful substances in the exhaust gas is filled, and the adsorbent is moved in the vertical direction substantially perpendicular to the passing direction of the exhaust gas, The moving bed type adsorption tower that discharges the adsorbent from the lower part, the regenerator that regenerates the adsorbent that has deteriorated the ability to remove harmful substances, and the ability to remove harmful substances from the adsorber tower to the regenerator is reduced. In an exhaust gas treatment facility comprising a first transport means for sending the adsorbent and a second transport means for sending the regenerated adsorbent to the adsorption tower from the regenerator, An impact applying means for impacting the exhaust gas outlet side wall of the lower hopper constituting the outlet portion is installed outside the side wall, and the side wall of the hopper parallel to the exhaust gas passage direction in the contracted portion at the lower part of the adsorption tower Adhesion almost parallel to Established the stop plate, the reproducing apparatus is installed sieved means at the bottom, the suction by the second transport means on a sieve to remove the fines from the adsorbent as a coarse adsorbent by sieve have interface unit exhaust gas treatment equipment according to claim Rukoto sent to the tower.
(2) The exhaust gas treatment facility according to (1), wherein the impact applying means is a knocker or a vibrator.
(3) The exhaust gas treatment facility according to (1) or (2), wherein a roll feeder that cuts out and discharges the adsorbent is installed at an outlet portion at a lower portion of the adsorption tower.

  ADVANTAGE OF THE INVENTION According to this invention, the raise of the ventilation resistance of the packed bed formed with an adsorbent can be suppressed, and the operation of exhaust gas treatment can be performed stably for a long period of time. For this reason, the efficiency of exhaust gas treatment is improved and the cost is also reduced.

  In order to perform long-term continuous operation of an exhaust gas treatment facility, the inventors have repeatedly studied a method for avoiding an increase in ventilation resistance (pressure loss) in an adsorption tower in which a packed bed filled with an adsorbent is formed. It was. As a result, the cause of the increase in the ventilation resistance of the adsorption tower is that, in addition to the powdering of the adsorbent, the accumulation of dust, etc., the particle diameter of the adsorbent in the adsorption tower becomes finer than expected. Yes, it is possible to suppress the increase in ventilation resistance of the adsorption tower by removing fine particles from the regenerated adsorbent and reusing only the coarse adsorbent having a particle diameter of 2 mm or more in the adsorption tower. The present inventors have found that it is important to install a sieving device after regeneration and to screen the adsorbent to a predetermined particle size. In particular, the occurrence of clogging with dust in the lower part of the adsorption tower affects the increase in the ventilation resistance of the adsorption tower, and in order to prevent clogging, it is effective to install impact applying means such as a knocker. I found out. The present invention obtained from the above knowledge is a moving bed type adsorption tower filled with an adsorbent for removing harmful substances in exhaust gas, a regeneration tower for regenerating an adsorbent with reduced harmful substance removal performance, In an exhaust gas treatment facility comprising a first transport means for sending an adsorbent having a reduced ability to remove harmful substances from a tower to a regeneration tower, and a second transport means for sending the regenerated adsorbent to the adsorption tower. An exhaust gas treatment facility characterized in that an impact applying means for impacting a side wall of a lower hopper which is an outlet portion of an adsorbent at the lower part of the tower is installed outside the side wall, and a sieving means is installed at the lower part of the regeneration tower. . It is preferable to use a knocker or a vibrator as the impact applying means, and to install the impact applying means on the side wall of the lower hopper which is the lower part of the adsorption tower on the exhaust gas side.

  In addition to the above, it is preferable to install a roll feeder that cuts out and discharges the adsorbent at the outlet of the lower hopper below the adsorption tower.

  Hereinafter, the exhaust gas treatment facility of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic view of an embodiment of the exhaust gas treatment facility of the present invention. In FIG. 1, 1 is a moving bed type adsorption tower filled with an adsorbent for removing harmful substances, 2 is a regeneration tower which is a regeneration apparatus for regenerating an adsorbent with reduced harmful substance removal performance, and 3 is an adsorption tower. 4 is a transport means for sending the adsorbent having a reduced ability of removing harmful substances from the regeneration tower to the regenerator, and 4 is a transport means for sending the regenerated adsorbent from the regeneration tower to the adsorption tower. Further, 5 is an adsorbent hopper, 6 is an adsorbent storage tank, 7 is a booster, 8 is a chimney, 9 is a vibrating sieve, and 10 is a fine particle adsorbent hopper.

  FIG. 2 is a schematic view of a lower section of the adsorption tower 1. A knocker 12 is installed on the outside of the side wall of the lower hopper 11 which is the exit portion of the adsorption tower 1. The knocker 12 is an impact applying means, and is installed for the purpose of giving an impact to the outside of the side wall of the lower hopper 11 and improving the flow of the adsorbent. For example, an air knocker, an electromagnetic knocker, or a vibrator can be used. Reference numeral 13 denotes a roll feeder for cutting out the adsorbent, which is installed as necessary.

  First, the sieving means installed at the lower part of the regeneration tower will be described. In order to remove fine particles from the adsorbent material so that only coarse particles are obtained, it is necessary to use a sieve such as a vibrating sieve 9 or the like. Fine particles can be removed from the adsorbent by a sieving process, and the top of the sieve can be made into a coarse adsorbent. If only dust is to be removed, it can be dealt with by installing a wind separator at the outlet of the regeneration tower that regenerates the adsorbent. However, the regenerated adsorbent has a predetermined particle size distribution. In order to use it, it is necessary to install a sieving means at the exit of the regeneration tower. The sieve mesh of the sieving means is preferably 2 mm or more. When the aperture of the screen used as a sieve is slit-like, the shortest length is preferably 2 mm or more. It is particularly preferable to perform sieving using a screen having an opening of 3 mm or more.

  Next, an impact applying means for applying an impact to the side wall of the lower hopper which is the outlet portion of the adsorbent at the lower part of the adsorption tower will be described. In the lower part of the adsorption tower, in order to discharge the adsorbent, as shown in FIG. 2, a side wall is inclined to form a hopper, and the adsorbent stays in this portion. The installation effect of the knocker as the impact applying means will be described with reference to FIG. FIG. 3 is a cross-sectional view of the lower part of the adsorption tower 1, and the exhaust gas flows from the left to the right toward the paper surface. The arrow shown with a dotted line is the flow of an adsorbent. An exhaust gas outlet portion of the adsorption tower 1 is constituted by a punching plate 15. As shown in FIG. 3A, when the adsorbent stagnation 16 occurs, large-scale clogging occurs in the lower portion of the punching plate 15 (the portion surrounded by the dotted oval). On the other hand, by installing a knocker and giving an impact to the side wall of the lower hopper 11, the adsorbent stay 16 is removed as shown in FIG. 3B, and the punching plate 15 is clogged. Can be prevented, the flow of the adsorbent can be kept good, and clogging can be prevented.

  For the above reason, it is preferable to install the impact applying means on the side wall of the lower hopper, which is the lower part of the adsorption tower on the exhaust gas side. When installing a larger number of impact applying means, the side wall of the lower hopper, which is the lower part of the left and right positions of the exhaust gas flow path (in parallel with the flow of the exhaust gas), centering on the lower hopper side wall on the exhaust gas exit side of the adsorption tower. It is preferable to install it on a side wall portion. Even when the impact applying means is installed in the side wall portion parallel to the flow of the exhaust gas, it is more preferable to install it in the portion near the side wall of the lower hopper, which is the lower part of the adsorption tower on the exhaust gas outlet side.

  In addition to the above, it is preferable to install a roll feeder that cuts out and discharges the adsorbent at the outlet of the lower hopper, which is the lower part of the lower hopper below the adsorption tower. Even when the inside of the adsorption tower is divided and the moving bed is divided into a plurality of moving beds, the adsorbing material in each moving bed is discharged uniformly, and the circulation amount of the adsorbing material is leveled. In FIG. 2, reference numeral 14 denotes a perforated plate for dividing the inside of the adsorption tower 1. In this case, the adsorbent is divided into three layers and falls in the adsorption tower 1. By using the roll feeder 13, it is possible to prevent the central layer from being preferentially discharged, and to discharge the entire layer more uniformly, and also to prevent clogging.

  Further, in addition to the above, an adhesion preventing plate 17 as shown in FIG. 4 is provided inside the hopper portion parallel to the side wall (side wall portion parallel to the exhaust gas flow) of the lower hopper, which is the lower portion of the left and right positions of the exhaust gas flow path. It is preferable to install. When dust or the like adheres to the side wall portion of the lower hopper, the load applied from the upper portion to the attached dust portion can be reduced by installing the adhesion preventing plate 17, so that dust can be effectively prevented from sticking. Can do. FIG. 4A is a top view of the lower hopper portion at the lower part of the adsorption tower, and FIG. 4B is a perspective view. The arrows in FIG. 4 indicate the direction in which the exhaust gas flows. The adhesion prevention plate 17 has a structure that is divided into three in the vertical direction by the presence of the partition plate 14. The adhesion preventing plate is preferably installed almost in parallel with the side wall of the lower hopper, and is installed in the lower hopper in a slightly opened state. In FIG. 4B, the knocker 12 is not shown.

  Next, a method for treating exhaust gas using the above equipment will be described. In general, a carbonaceous adsorbent is used as an adsorbent used for treating exhaust gas generated from a sintering machine for producing sintered ore. Therefore, the following will describe the exhaust gas treatment method of the present invention in the case where a carbonaceous adsorbent is used. Examples of the carbonaceous adsorbent include activated carbon and activated coke, and it is particularly preferable to use activated coke.

In FIG. 1, the exhaust gas A generated from the sintering machine is sucked by the booster 7 and removed from the main dust by the electric dust collector, and then introduced into the adsorption tower 1. The adsorption tower 1 is filled with a carbonaceous adsorbent to form a packed bed. The carbonaceous adsorbent is charged from the upper part 1a of the adsorption tower and cut out from the lower part 1b to adsorb in the adsorption tower 1. A moving bed of adsorbent from the tower upper part 1a to the lower part 1b is formed. Activated coke (activated carbon) is used as the carbonaceous adsorbent. As shown in FIG. 1, the exhaust gas is allowed to pass through the packed bed in a horizontal direction to bring the exhaust gas into contact with the carbonaceous adsorbent, so that dust and harmful substances (SO _X , NO _X , dioxin in the exhaust gas are brought into contact with each other. , Dust, etc.) are adsorbed on the carbonaceous adsorbent.

  The carbonaceous adsorbent cut out from the adsorption tower 1 is sent from the adsorption tower to the regeneration tower 2 as a regenerator by the transport means 3 and heated using hot air or the like. After cooling, the carbonaceous adsorbent has a predetermined particle size using the vibrating sieve 9. Only the coarse particles regenerated to a sufficiently active state after removing the following fine particles are sent from the regeneration tower 2 to the adsorption tower 1 by the transport means 4 and charged into the absorption tower 1 again. At the same time as the carbonaceous adsorbent having a predetermined particle size or less is removed as fine particles by the vibration sieve 9, dust is also removed. The shortage of the carbonaceous adsorbent is replenished from the carbonaceous adsorbent hopper 5 and the carbonaceous adsorbent storage tank 6.

  For example, a fine carbonaceous adsorbent having a particle diameter of less than 3 mm is removed by a sieving process using a vibration sieve 9, and a shock is applied to the side wall of the lower hopper 11 of the adsorption tower 1 by a knocker, thereby providing a ventilation resistance in the adsorption tower. It is possible to prevent the rise and carry out long-term continuous operation.

Schematic of one embodiment of the exhaust gas treatment facility of the present invention. The schematic of the cross section of the lower part of the adsorption tower in FIG. Explanatory drawing of the installation effect of an impact provision means. (A) Conventional example, (b) Invention example. Explanatory drawing of an adhesion prevention board. (A) Top view of lower hopper portion, (b) perspective view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adsorption tower 1a Adsorption tower upper part 1b Adsorption tower lower part 2 Regeneration tower 3 Transport means from adsorption tower to regeneration device 4 Transport means from regeneration tower to adsorption tower 5 Adsorbent hopper 6 Adsorbent storage tank 7 Booster 8 Chimney 9 Vibration sieve 10 Fine particle adsorber hopper 11 Lower hopper 12 Knocker 13 Roll feeder 14 Perforated plate 15 Punching plate 16 Adsorbent retention 17 Adhesion prevention plate A Exhaust gas

Claims (3)

In order to treat the exhaust gas generated when producing the sintered ore, the adsorbent for removing harmful substances in the exhaust gas is filled, the adsorbent is moved in the vertical direction substantially perpendicular to the passage direction of the exhaust gas, A moving bed type adsorption tower that discharges the adsorbent, a regenerator that regenerates the adsorbent whose harmful substance removal performance has been reduced, and the adsorption that has reduced the ability to remove harmful substances from the adsorber tower to the regenerator In an exhaust gas treatment facility comprising a first transport means for sending a material and a second transport means for sending the regenerated adsorbent from the regenerator to the adsorption tower, an outlet portion of the adsorbent at the lower part of the adsorption tower An impact applying means for giving an impact to the exhaust gas outlet side wall of the lower hopper is installed outside the side wall, and is substantially parallel to the side wall of the hopper parallel to the exhaust gas passage direction in the contraction part at the lower part of the adsorption tower. Anti-adhesion plate Installed, the set up sieving unit to the reproducing apparatus lower, feed to the adsorption tower by the second transport means on the sieve to remove the fines from the adsorbent as a coarse adsorbent by sieve have interface unit An exhaust gas treatment facility characterized by that. Exhaust gas treatment system according to claim 1, impact application means, characterized in that a knocker or vibrator.   The exhaust gas treatment facility according to claim 1 or 2, wherein a roll feeder that cuts out and discharges the adsorbent is installed at an outlet portion at a lower portion of the adsorption tower.

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