JP2007069072A - Equipment and method for processing exhaust gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an equipment and a method for processing exhaust gas capable of detecting generation of hot spot in an early stage, and processing the exhaust gas in an early stage of generation of the hot spot when processing exhaust gas generated in manufacturing sintered ores by a filled layer formed of an adsorbing material by cyclically using the adsorbing material. <P>SOLUTION: The processing equipment of exhaust gas generated when manufacturing sintered ores has a movable layer type adsorption tower filled with an adsorbing material for removing hazardous substances in the exhaust gas, and a plurality of thermometers are installed inside the adsorption tower at the spacing within 4 m in the moving direction of the adsorbing material at least at a lower part of the adsorption tower. In the exhaust gas processing method, the exhaust gas generated when manufacturing sintered ores is processed by using the exhaust gas processing equipment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an exhaust gas treatment facility and an exhaust gas treatment method for treating exhaust gas containing SO _x or the like generated when producing sintered ore.

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. Thus, an adsorption technique using a packed bed that is circulated and used is known.

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. Such a carbonaceous adsorbent whose activity has been temporarily reduced is conveyed to the top of a moving bed type regenerator, for example, and supplied into the regenerator through a supply valve. In the regenerator, it is heated and regenerated as it moves downward.

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.

  When the carbonaceous adsorbent is circulated and used as described above, a phenomenon called a hot spot in which the carbonaceous adsorbent partially becomes abnormally high in the packed bed may occur. When hot spots occur, it is necessary to stop the exhaust gas treatment and introduce an inert gas to stop the spread of the carbonaceous adsorbent, and in addition, the device that forms the packed bed may be deformed by heat, It is desirable to prevent the occurrence of hot spots that are forced into a long-term facility shutdown.

In order to prevent the occurrence of hot spots in the exhaust gas treatment using the adsorption technology by the packed bed using such a carbonaceous adsorbent, a low oxygen concentration gas is blown from the lower part of the packed bed, and the air below the packed bed is A technique for substituting a gas with a low oxygen concentration gas is known (for example, see Patent Document 1).
Japanese Patent No. 3537365

However, in the method using the technique of substituting the air under the packed bed with the low oxygen concentration gas, the carbonaceous adsorbent reacts with oxygen and generates heat in the lower part of the packed bed, particularly in the lower cone part. The cause is that the oxygen concentration in this portion is reduced to prevent the temperature from rising, but the hot spot is not necessarily generated only in the lower cone portion of the packed bed, so it is not a sufficient measure. The main causes of hot spot generation are the exothermic reaction due to adsorption of SO _{2 on} the carbonaceous adsorbent and the temperature rise of the carbonaceous adsorbent due to the heat of dilution generated when the generated sulfuric acid absorbs moisture in the exhaust gas. This is not necessarily a reaction in the lower cone.

  Therefore, realistically, when a hot spot occurs, it is important to quickly detect and cope with the temperature rise due to the occurrence.

  In view of the above, the object of the present invention is to solve such problems of the prior art, and to treat exhaust gas generated when producing sintered ore by circulating the adsorbent and forming the packed bed with the adsorbent. The present invention is to provide an exhaust gas treatment facility and an exhaust gas treatment method that can detect occurrence of a hot spot at an early stage and can cope with it at an initial stage of occurrence of the hot spot.

The features of the present invention for solving such problems are as follows.
(1) A treatment facility for exhaust gas generated when producing sintered ore, comprising a moving bed type adsorption tower filled with an adsorbent for removing harmful substances in the exhaust gas, and the interior of the adsorption tower A plurality of thermometers are installed at an interval of 4 m or less in the moving direction of the adsorbent at least in the lower part of the adsorption tower.
(2) An exhaust gas treatment method characterized by treating the exhaust gas produced when producing sintered ore using the exhaust gas treatment facility according to (1).
(3) The occurrence of a hot spot that is a temperature rising portion of the adsorbent is detected by a thermometer inside the adsorption tower, and after the occurrence of the hot spot is detected, an inert gas is blown into the adsorption tower at 3000 Nm ³ / h or more. The exhaust gas treatment method according to (2), which is characterized.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the hot spot from which the packed bed formed with an adsorbent becomes high temperature locally can be detected at an early stage, and can be dealt with in the initial stage of hot spot generation. For this reason, the operating rate of the exhaust gas treatment facility is improved, the deformation of the facility due to heat can be prevented, and the cost is reduced.

The inventors of the present invention, when processing exhaust gas generated when producing sintered ore with a processing facility having a moving bed type adsorption tower filled with an adsorbent for removing harmful substances in the exhaust gas, A method for monitoring a phenomenon in which an abnormally high temperature portion (hereinafter referred to as a “hot spot”) of the adsorbent is generated using a thermometer was examined. In the exhaust gas treatment facility for sintered ore, the height of the adsorption tower is about 20 m, although it varies depending on the exhaust gas treatment amount and required specifications, and the adsorbent passes through the adsorption tower in about 5 days. It has been found that a thermometer installed in such an adsorption tower can detect the temperature rise of the adsorbent within about 2 m before and after. From this, it was considered that the installation interval of the thermometer should be about 4 m. Also, the hot spot contains a lot of dust in the exhaust gas, the influence of the lowering of the ignition point of the adsorbent due to the catalytic effect of the dust component contained in the exhaust gas is large, and the time of exposure to the exothermic reaction due to adsorption of SO ₂ is long It was found that it is highly likely to occur in the lower part of the adsorption tower, and it is important to install thermometers closely in the lower part of the adsorption tower. Accordingly, at least in the lower half of the adsorption tower, it is effective for early detection of hot spots to use an exhaust gas treatment facility in which a thermometer is installed with an interval in the moving direction of the adsorbent within 4 m. In the upper half of the adsorption tower, a thermometer may be installed with an interval in the moving direction of the adsorbent within 4 m. However, in order to reduce the cost of installing the thermometer, an interval of about 5 m is practical. Is fine. It is appropriate to use a thermocouple as the thermometer. It is important to measure the temperature at the thermometer installation position inside the adsorption tower, and the thermometer installation position indicates the temperature measurement position in the adsorption tower. Therefore, if the temperature at the thermometer installation position can be measured, the main body of the thermometer can be installed at a location away from the adsorption tower.

  As described above, the exhaust gas generated when the sintered ore is produced is processed using the exhaust gas processing facility in which the thermometer for measuring the temperature inside the adsorption tower is installed. By using such an exhaust gas treatment method, it becomes possible to detect the temperature rise of the adsorbent at an early stage and prevent the occurrence of hot spots in advance, or to detect them simultaneously with the occurrence, and further limit the range of hot spots. Preventing disasters and returning to operation after hotspot response measures will be faster than before.

  The occurrence of a hot spot is detected by a rise in temperature inside the adsorption tower. For example, when a thermometer that measures the temperature of the adsorbent inside the adsorption tower detects 180 ° C., it can be determined that a hot spot has occurred. The hot spot detection temperature is preferably about 150 to 190 ° C.

When a hot spot is detected, it is preferable to stop the circulation of the adsorbent and to blow more than 3000 Nm ³ / h (N represents the volume in the standard state) of inert gas per tower. By blowing a large amount of inert gas, the inside of the adsorption tower can be immediately put into an inert gas atmosphere, and the expansion of hot spots can be prevented. More preferably, an inert gas of 3900 Nm ³ / h or more is blown. It is desirable to use nitrogen gas as the inert gas.

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

  FIG. 1 shows a schematic view of an embodiment of an exhaust gas treatment facility used in 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 vertical cross-sectional view of the adsorption tower 1 and is a schematic view showing the position of a thermometer arranged inside the adsorption tower. When the height of the adsorption tower is 20 m, when the thermometer 20 is installed as shown in FIG. 2A, the interval in the moving direction (height direction) of the adsorbent of the thermometer 20 in the lower half of the adsorption tower 1 Is 10 m, and it is difficult to detect hot spots in such an arrangement. On the other hand, when the thermometer 20 is installed as shown in FIG. 2B, the interval in the moving direction (height direction) of the adsorbent of the thermometer 20 in the lower half of the adsorption tower 1 is 2.5 m. The interval between the thermometers 20 in the upper half of the tower 1 is 5 m. With this arrangement, hot spots can be detected almost simultaneously with the occurrence. Although it is desirable that the number of thermometers is increased, the thermometers are set to be at least 4 m in the lower half of the adsorption tower 1.

  Next, a method for treating exhaust gas using the facilities shown in FIGS. 1 and 2B 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 the 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). , 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. The adsorbent regenerated to a sufficiently active state by removing fine particles and dust below the particle size is sent from the regenerating tower 2 to the adsorbing tower 1 by the transport means 4 and charged again into the absorption tower 1. The The shortage of the carbonaceous adsorbent is replenished from the carbonaceous adsorbent hopper 5 and the carbonaceous adsorbent storage tank 6.

  The temperature of the adsorption tower during operation is monitored using a thermometer 20. When a high temperature portion of 160 ° C. or higher occurs at any position in the adsorption tower 1, it is determined that a hot spot is generated, the operation of the adsorption tower is stopped, and an inert gas is blown into the adsorption tower. . After confirming a decrease in temperature in the adsorption tower 1, the operation is resumed.

The exhaust gas generated from the sintering machine at the steelworks was treated using the same equipment as in FIG. Thermometers for measuring the temperature inside the adsorption tower were arranged in the vertical direction of the adsorption tower as shown in FIG. 2 (a), and 252 thermometers were installed in the entire adsorption tower equipment. As the adsorbent, using activated coke, which is a carbonaceous adsorbent, from the exhaust gas of 1000000 Nm ³ / h, an operation was carried out to perform dedioxin and desulfurization treatment. The tower was cooled by blowing nitrogen gas at 900 Nm ³ / h. When the operation was stopped and the inside of the adsorption tower was confirmed, the partition plate inside the adsorption tower was deformed by heat. It was difficult to detect the occurrence of hot spots in advance.

Therefore, as shown in FIG. 2 (b), a total of 336 thermometers inside the adsorption tower are arranged in four places in the longitudinal direction, and a total of 336 thermometers are installed. It was in a state. As a result, the generation of the high temperature portion can be reliably detected. When the high temperature portion of 160 ° C. or higher was generated, the exhaust gas treatment was stopped, and nitrogen gas was blown into the adsorption tower at 3900 Nm ³ / h to be cooled. This operation makes it possible to immediately detect the occurrence of a hot spot and respond quickly.

Schematic of one embodiment of an exhaust gas treatment facility used in the present invention. Schematic which shows the thermometer position arrange | positioned inside the adsorption tower.

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 Vibrating sieve 10 Fine particle adsorber hopper 20 Thermometer A Exhaust gas

Claims (3)

  A facility for treating exhaust gas produced when producing sintered ore, comprising a moving bed type adsorption tower filled with an adsorbent for removing harmful substances in the exhaust gas, and a plurality of temperatures inside the adsorption tower An exhaust gas treatment facility characterized in that a meter is installed at least in the lower part of the adsorption tower with an interval in the moving direction of the adsorbent within 4 m.   An exhaust gas treatment method comprising treating exhaust gas produced when producing sintered ore using the exhaust gas treatment facility according to claim 1. The generation of a hot spot, which is a temperature rising portion of the adsorbent, is detected by a thermometer inside the adsorption tower, and after detecting the occurrence of the hot spot, an inert gas is blown into the adsorption tower at 3000 Nm ³ / h or more. Item 3. An exhaust gas treatment method according to Item 2.

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