JP5355939B2 - Exhaust gas treatment apparatus and exhaust gas treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for treating an exhaust gas which can suppress the rise of a pressure loss inside an adsorbing column while suppressing the increase of the cost. <P>SOLUTION: The apparatus for treating the exhaust gas is provided with: the adsorbing column 30 eliminating harmful materials by a medium; a desorbing column 2 regenerating the medium; a transfer line 3a transferring the medium discharged from the adsorbing column 30 to the desorbing column 2; a return line 3b, 3c returning the medium regenerated in the desorbing column 2 to the adsorbing column 30; and a circulation line 4 returning the medium discharged from the adsorbing column 30 to the adsorbing column 30. The adsorbing column 30 possesses an introducing part 8, a first reaction chamber, a second reaction chamber, a first recovery hopper 16 recovering the medium discharged from the first reaction chamber and a second recovery hopper 17 recovering the medium discharged from the second reaction chamber. The introducing part 8 is connected to the return line 3b, 3c and the circulation line 4, the first recovery hopper 16 is connected to the transfer line 3a, and the second recovery hopper 16 is connected to the circulation line 17. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an exhaust gas treatment apparatus and an exhaust gas treatment method.

  Conventionally, when removing harmful substances such as SOx, NOx, dioxin, dust and soot from exhaust gas generated from boilers such as power generation boilers, sintering furnaces or sintering machines such as steelworks, various chemical plants, etc., dry-type An exhaust gas treatment method using an exhaust gas treatment apparatus is used.

  In such exhaust gas treatment, a medium such as a granular carbonaceous adsorbent is vertically supplied from the upper part of the adsorption tower, and exhaust gas mixed with a reducing agent such as ammonia is introduced into the adsorption tower in a horizontal direction. An AC moving bed is used.

  In this case, advanced exhaust gas treatment is performed by collision collection of the particles to the medium when the particle diameter of the harmful substance exceeds 1 μm, and diffusion collection when the particle diameter of the harmful substance is 1 μm or less. On the other hand, there is a problem that the pressure loss increases due to the easy accumulation of the particles in the moving layer.

  In addition, the medium becomes finer due to friction and impact during the movement of the medium and a decrease in the medium strength due to chemical wear that occurs when the medium is regenerated in the desorption tower. The finely divided medium exhibits a behavior equivalent to that of harmful substance particles, and the finely divided medium and the particles form a close packed structure, which also helps increase the pressure loss.

  Another cause of the increase in pressure loss is that the outlet of the reaction chamber in the adsorption tower has a constricted shape, so that the uniform descent of the medium is hindered, soot or dust accumulates in a part of the moving bed, and the exhaust gas drifts. It is generated. In order to reduce the influence of this throttle shape, the reaction chamber is divided into multiple layers from the upstream side toward the downstream side, and a roll feeder is provided at the outlet of each layer to individually control the flow rate of the medium in each layer, A method for effectively discharging the dust trapped in the medium has been proposed.

  However, in the above-described method, when the pressure loss increases, a large amount of exhaust gas is diverted from the previous layer of the reaction chamber to the subsequent layer through this roll feeder, resulting in fluidization of the medium, There was a problem that the descent speed could not be controlled and the vehicle could not be driven. Therefore, Patent Document 1 below proposes a method for preventing the bypass flow of the exhaust gas. Specifically, a method is disclosed in which a detour flow of exhaust gas is prevented by providing a partition in the discharge portion of the adsorption tower.

JP 2005-296760 A

  However, even the exhaust gas treatment apparatus described in Patent Document 1 has a risk of increasing pressure loss due to accumulation of harmful substances in the adsorption tower.

  Therefore, it is conceivable to increase the regeneration capacity by enlarging the desorption tower that regenerates the medium and increasing the amount of medium drawn from the adsorption tower, but increases the equipment cost and the cost of fuel used during heat regeneration, etc. There was also a problem in terms of cost.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust gas treatment apparatus and an exhaust gas treatment method capable of suppressing an increase in pressure loss in an adsorption tower while suppressing an increase in cost. .

  In the exhaust gas treatment apparatus of the present invention, an adsorption tower that contains a medium and removes harmful substances by passing the exhaust gas through the medium, a desorption tower that regenerates the medium with reduced activity, and a medium discharged from the adsorption tower are removed. A transport line for transporting to the separation tower, a return line for returning the medium regenerated in the desorption tower to the adsorption tower, and a circulation line for returning the medium discharged from the adsorption tower to the adsorption tower. Introducing section into which the medium is introduced, first reaction chamber located upstream in the exhaust gas flow direction, second reaction chamber located downstream in the exhaust gas flow direction, medium discharged from the first reaction chamber And a second recovery hopper for recovering the medium discharged from the second reaction chamber, and the introduction part of the adsorption tower is connected to the return line and the circulation line, The first recovery hopper of the adsorption tower is connected to the transfer line. It is continued, a second recovery hopper of the adsorption tower is characterized in that it is connected to the circulation line.

  When exhaust gas treatment is performed, a lot of harmful substances adhere to the first reaction chamber located upstream in the exhaust gas flow direction in the adsorption tower, and the second reaction chamber located downstream in the exhaust gas flow direction Tend to have less harmful substances. Therefore, according to the present invention, it is possible to circulate the medium discharged from the second recovery hopper and unnecessary for regeneration in the desorption tower to the adsorption tower through the circulation line. Thereby, the regeneration processing amount of the medium discharged from the first recovery hopper and requiring regeneration in the desorption tower can be increased without enlarging the desorption tower. Therefore, even when a large amount of exhaust gas treatment is performed, it is possible to reduce pressure loss in the adsorption tower while suppressing an increase in cost. In addition, the medium that is discharged from the second recovery hopper and does not need to be regenerated in the desorption tower can be recycled and reused without sieving. It becomes.

  The "pressure loss" is caused by the fluid resistance when exhaust gas passes through a medium such as a carbonaceous adsorbent in the adsorption tower, and when the medium is used with a certain exhaust gas treatment air volume, It represents the difference (decrease) in air pressure (static pressure) generated between the exhaust gas inlet and the exhaust gas outlet of the adsorption tower. The unit is expressed in Pa, and a pressure gauge is used for this measurement.

  Furthermore, the second recovery hopper of the adsorption tower is also connected to the transfer line, and it is preferable that the connection can be switched between the transfer line and the circulation line.

  As a result, the medium discharged from the second recovery hopper can be transferred from the transfer line to the circulation line. Therefore, the amount of the medium recovered by the first recovery hopper and regenerated in the desorption tower is increased by the amount of the medium recovered by the second recovery hopper and not required to be regenerated in the desorption tower. It becomes possible. Therefore, if necessary, it is possible to increase the amount of regeneration processing of the medium that needs to be regenerated in the desorption tower and reduce the pressure loss in the adsorption tower. Furthermore, if necessary, it is also possible to return to the original state and return the connection of the second recovery hopper from the circulation line to the transport line.

  In the exhaust gas treatment method of the present invention using the exhaust gas treatment apparatus, the medium recovered by the first recovery hopper is transported to the desorption tower via the transport line and regenerated, and the regenerated medium is adsorbed via the return line. The medium returned to the tower and recovered by the second recovery hopper is returned to the adsorption tower through a circulation line.

  According to the present invention, it is possible to circulate the medium discharged from the second recovery hopper and unnecessary for regeneration in the desorption tower to the adsorption tower by the circulation line. Thereby, the regeneration processing amount of the medium discharged from the first recovery hopper and requiring regeneration in the desorption tower can be increased without enlarging the desorption tower. Therefore, even when a large amount of exhaust gas treatment is performed, it is possible to reduce pressure loss in the adsorption tower while suppressing an increase in cost. In addition, the medium that is discharged from the second recovery hopper and does not need to be regenerated in the desorption tower can be recycled and reused without sieving, so that the medium can be used effectively and the wear of the medium can be reduced. It becomes.

  In the exhaust gas treatment method of the present invention using the exhaust gas treatment apparatus, if the pressure loss in the adsorption tower is less than a predetermined first threshold value, the medium recovered by the first and second recovery hoppers is transferred to the transport line. When the pressure loss in the adsorption tower is equal to or higher than the first threshold value, the low pressure loss operation is performed by transferring the regenerated medium to the adsorption tower via the return line and returning the regenerated medium to the adsorption tower via the return line. The medium recovered by the first recovery hopper is transported to the desorption tower via the transport line and regenerated, the recovered medium is returned to the adsorption tower via the return line, and the medium recovered by the second recovery hopper It is preferable to perform the operation at the time of high pressure loss to return the gas to the adsorption tower through the circulation line.

  As a result, when the pressure loss in the adsorption tower is sufficiently low, all the medium can be circulated to the adsorption tower via the desorption tower. When the pressure loss increases and exceeds the first threshold value, the conveyance path of the medium recovered by the second recovery hopper is adsorbed from the path returning to the adsorption tower via the desorption tower without passing through the desorption tower. By switching to the path for returning to the tower, the medium that needs to be regenerated in the desorption tower can be quickly regenerated, and the pressure loss in the adsorption tower can be reduced.

  In the exhaust gas treatment method of the present invention using the exhaust gas treatment apparatus, when the pressure loss in the adsorption tower is equal to or higher than the first threshold value, the pressure loss in the adsorption tower falls below a second threshold value that is smaller than the first threshold value. It is preferable to perform the operation at the time of high pressure loss.

  As a result, the pressure loss in the adsorption tower is reduced to a second threshold value that is smaller than the first threshold value. Therefore, even if the pressure loss rises as the exhaust gas treatment time elapses again, the pressure loss in the adsorption tower is reduced. Until at least the first threshold value is raised, the exhaust gas treatment can be suitably continued.

  ADVANTAGE OF THE INVENTION According to this invention, the pressure loss in an adsorption tower can be reduced, and the exhaust gas processing apparatus and exhaust gas processing method which can suppress the increase in cost can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratio in each drawing does not necessarily match the actual dimensional ratio.

(First embodiment)
The exhaust gas treatment apparatus and the exhaust gas treatment method according to the first embodiment of the present invention are applied to, for example, a steel mill and the like, and sulfur oxide (SOx) and nitrogen oxide ( NOx), heavy metals such as hydrogen chloride and mercury, organic chlorine compounds such as dioxins, dust, and harmful substances such as soot are removed using a carbonaceous adsorbent (medium).

  The carbonaceous adsorbent is in the form of pellets, and is composed of, for example, activated carbon, activated coke, activated char, etc. (abbreviated as AC) and has the ability to adsorb and decompose harmful components contained in exhaust gas. Yes.

  Hereinafter, the exhaust gas treatment apparatus according to the first embodiment will be described. FIG. 1 is a schematic diagram showing an exhaust gas treatment apparatus 100. The exhaust gas treatment apparatus 100 includes an adsorption facility 1, a desorption tower 2, a transfer line 3a, return lines 3b and 3c, and a circulation line 4.

  As shown in FIG. 1, the exhaust gas treatment apparatus 100 further includes a receiving hopper 5 and a storage tank 6. The receiving hopper 5 is a container in which a carbonaceous adsorbent (AC) can be dropped and taken out from a bottom-open funnel-type mouth. The storage tank 6 is provided with a roll feeder RF4 and a roll feeder operator M4.

Further, in order to remove harmful substances contained in the exhaust gas by adding ammonia to the exhaust gas, the exhaust gas treatment device 100 includes a liquid ammonia supply device, an ammonia vaporizer, and an ammonia gas addition device (not shown). ).

  Hereinafter, the adsorption facility 1 will be described. Although FIG. 1 shows an example in which three adsorption towers 30 are provided in the adsorption facility 1, the number of adsorption towers 30 is not limited to this. In other words, it is sufficient that at least one adsorption tower 30 is provided in the adsorption facility 1.

  FIG. 2 is a schematic cross-sectional view of one adsorption tower 30 in the adsorption facility 1. The adsorption tower 30 introduces the exhaust gas W in the horizontal direction, and removes the harmful substances by containing and contacting the carbonaceous adsorbent P (medium) that adsorbs the harmful substances in the exhaust gas so as to flow in the vertical direction. This is a so-called cross-flow type moving bed type adsorption tower.

  As shown in FIG. 2, the upper part of the adsorption tower 30 is provided with an introduction part 8 into which a medium is introduced and an opening / closing valve V1, and the opening / closing valve V1 is an air for taking in and out the medium while preventing leakage of exhaust gas. It is a lock valve, and supplies the carbonaceous adsorbent P supplied from the introduction part 8 while preventing leakage of exhaust gas. An example of the on-off valve V1 is a rotary valve.

  Exhaust gas inlets 14 and exhaust gas outlets 15 are respectively disposed on opposite sides of the adsorption tower 30. Inside the adsorption tower 30, a front wall 9a, a partition wall 10a, a partition wall 10b, and a rear wall 9b each having an opening through which the exhaust gas W passes are vertically arranged in this order from the exhaust gas inlet 14 side to the exhaust gas outlet 15 side. It is arranged to extend. As the front wall 9a and the rear wall 9b, for example, a louver member in the shape of a loyal door is mentioned. Examples of the partition wall 10a and the partition wall 10b include a perforated plate.

  The inside of the adsorption tower 30 is divided into a front chamber 11a between the front wall 9a and the partition wall 10a, a middle chamber 11b between the partition wall 10a and the partition wall 10b, and a rear chamber 11c between the partition wall 10b and the rear wall 9b. ing. Each of the front chamber 11a, the middle chamber 11b, and the rear chamber 11c is filled with a carbonaceous adsorbent P to form a moving layer. The front chamber 11a and the middle chamber 11b positioned on the upstream side in the exhaust gas flow direction are referred to as a first reaction chamber, and the rear chamber 11c positioned on the downstream side in the exhaust gas flow direction is referred to as a second reaction chamber.

  A single-drawer-shaped lower hopper 12a and a roll feeder RF1a are arranged in the lower portion of the front chamber 11a, and a single-drawer-shaped lower hopper 12b and a roll feeder RF1b are arranged in the lower portion of the middle chamber 11b, and the rear chamber 11c. A single-drawer-shaped lower hopper 12c and a roll feeder RF2 are arranged at the lower part of the sheet feeder. The lower hoppers 12a and 12b are containers capable of dropping and removing a carbonaceous adsorbent from a bottom-open funnel-shaped mouth, and are formed of, for example, an iron plate.

  The lower ends of the lower hoppers 12a and 12b provided with the roll feeders RF1a, RF1b, and RF2 are determined according to the size of the carbonaceous adsorbent P, but are usually opened by 10 to 40 mm. The carbonaceous adsorption discharged from the opening by, for example, electrically controlling the rotation of the roll feeders RF1a, RF1b, and RF2 by a roll feeder operator M1 (shown in FIG. 1) provided outside the adsorption tower 30. The discharge speed of the material P is controlled. Note that the roll feeders RF1a and RF1b shown in FIG. 2 correspond to the roll feeder RF1 shown in FIG.

  Further, at the lower part of the adsorption tower 30, a first recovery hopper 16 that recovers the carbonaceous adsorbent P discharged from the first reaction chamber via the roll feeders RF1a and RF1b, and a roll from the second reaction chamber. A second recovery hopper 17 for recovering the carbonaceous adsorbent P discharged through the feeder RF2 is provided.

  A first recovery region X of the carbonaceous adsorbent P formed inside the first recovery hopper 16 and a second recovery region Y of the carbonaceous adsorbent P formed inside the second recovery hopper 17. Since the partition M is provided between the first recovery area X and the second recovery area Y, the first recovery area X and the second recovery area Y are independent from each other. As a result, the carbonaceous adsorbent P recovered in the first recovery region X and the second recovery region Y is mixed, and exhaust gas is discharged from the front chamber 11a and the middle chamber 11b via the roll feeders RF1a, 1b and RF2. It is possible to prevent detouring to the rear chamber 11c.

  The lower part of the first recovery hopper 16 has, for example, an inverted quadrangular pyramid shape, and an adsorbent extraction nozzle 18 for extracting the carbonaceous adsorbent P at the lower end of the center of the first recovery hopper 16, and this extraction There is provided an open / close valve V2 that performs discharge while preventing leakage of exhaust gas. Similarly, the lower part of the second recovery hopper 17 has, for example, an inverted quadrangular pyramid shape, and an adsorbent extraction nozzle 19 for extracting the carbonaceous adsorbent P at the center lower end of the second recovery hopper 17. An open / close valve V3 for extracting the adsorbent is provided. Examples of the open / close valves V2 and V3 include a rotary valve.

  The first recovery hopper 16 is connected to a later-described transport line 3a via an adsorbent extraction nozzle 18 and an opening / closing valve V2. The second recovery hopper 17 is connected to a circulation line 4 to be described later via an adsorbent extraction nozzle 19 and an opening / closing valve V3.

  Next, the desorption tower 2 for regenerating the carbonaceous adsorbent with reduced activity will be described. As shown in FIG. 1, a roll feeder RF3 is provided inside the desorption tower 2, and the rotation of the roll feeder RF3 is controlled by a roll feeder operating unit M3 provided outside the desorption tower 2, so that the carbonaceous matter is removed. The adsorbent is discharged. Opening / closing valves V4 and V5 are arranged at the upper and lower parts of the desorption tower 2, respectively. Examples of the open / close valves V4 and V5 include a rotary valve. Although not shown, the desorption tower 2 is provided with a heat source supply device such as a multi-tube heat exchanger including a heating device and a cooling device, and a hot stove.

  Next, the conveyance line 3a, the return lines 3b and 3c, and the circulation line 4 will be described. The conveyance line 3 a is a line that connects the first recovery hopper 16 and the desorption tower 2 and conveys the carbonaceous adsorbent discharged from the adsorption tower 30 to the desorption tower 2. The return line 3 b is a line that connects the desorption tower 2 and a sieving machine 7 to be described later and conveys the carbonaceous adsorbent regenerated in the detachment tower 2 to the sieving machine 7. The return line 3 c is a line that connects the sieving machine 7 and the introduction part 8 of the adsorption tower 30 and returns the carbonaceous adsorbent separated by the sieving machine 7 to the adsorption tower 30. The circulation line 4 is a line that connects the second recovery hopper 17 and the adsorption tower 30 and returns the carbonaceous adsorbent discharged from the adsorption tower 30 to the adsorption tower 30. The return line 3 c and the circulation line 4 are connected to the introduction part 8 of the adsorption tower 30.

  The conveyance line 3a, the return line 3c, and the circulation line 4 are conveyors such as a conveyor, and examples thereof include a belt conveyor and a bucket conveyor. The belt conveyor is a transporter that moves a belt member made of rubber on a roll member, and moves a medium on the belt member. On the other hand, a bucket conveyor is a transporter that accommodates and moves a medium in a so-called bucket-shaped container. The return line 3b is a chute.

  In order to convey the carbonaceous adsorbent as stationary as possible, it is preferable to use bucket conveyors for the conveyance line 3a and the return line 3c. On the other hand, a belt conveyor is preferably used for the circulation line 4 from the viewpoint of suppressing an increase in cost.

  An example of the sieving machine 7 is a vibrating sieve.

  Next, the exhaust gas treatment method according to the first embodiment of the present invention will be described.

  First, as shown in FIG. 1, the carbonaceous adsorbent before being circulated to the adsorption tower 30 and the desorption tower 2 is stored in the receiving hopper 5. Then, the carbonaceous adsorbent taken out from the receiving hopper 5 is stored in the storage tank 6. In the storage tank 6, the carbonaceous adsorbent is discharged by controlling the rotation of the roll feeder RF4 by the roll feeder operating device M4.

  Next, the adsorption tower 30, the desorption tower 2, the transport line 3a, and the return line 3c are driven to start circulation of the carbonaceous adsorbent. Then, the carbonaceous adsorbent conveyed to the desorption tower 2 is heated and regenerated and transferred from the desorption tower 2 to the sieving machine 7 through the return line 3b. Dust, fine particles of carbonaceous adsorbent, etc. are removed from the carbonaceous adsorbent regenerated in the desorption tower 2 by the sieving machine 7. In addition, the carbonaceous adsorbent discharged from the storage tank 6 is transported to the desorption tower 2 via the transport line 3a.

  Thereafter, the carbonaceous adsorbent is returned from the sieving machine 7 to the adsorption tower 30 via the return line 3c. In the adsorption tower 30, a moving layer of a carbonaceous adsorbent is formed and, for example, ammonia added to exhaust gas discharged from a sintering furnace or the like is introduced into the adsorption tower 30 through an exhaust gas introduction line (not shown). To do.

  Ammonia is added, for example, as follows. First, liquid ammonia is supplied to an ammonia vaporizer from a liquid ammonia supply device (not shown) and vaporized to generate ammonia gas. Next, the generated ammonia gas is added to the exhaust gas using an ammonia gas addition device.

As a result, ammonia can be added to the exhaust gas introduced into the adsorption tower 30, and harmful substances (for example, NO _x ) contained in the exhaust gas can be removed by catalytic reaction. For example, NO _x nitrogen oxides, the catalytic action of the carbonaceous adsorbent, that is, removed turned been reduced nitrogen and water by reaction with ammonia adsorbed on the carbonaceous adsorbent.

  A part of the carbonaceous adsorbent after contacting the exhaust gas in the adsorption tower 30 is recovered by the first recovery hopper 16 of the adsorption tower 30 and then transferred to the desorption tower 2 via the transfer line 3a. That is, the carbonaceous adsorbent that needs to be regenerated is transported to the desorption tower 2.

  In the desorption tower 2, the carbonaceous adsorbent is introduced from the top of the desorption tower 2 via the opening / closing valve V4, and the carbonaceous adsorbent is discharged from the bottom of the desorption tower 2 via the opening / closing valve V5. To form a vertically downward moving layer. For example, the carbonaceous adsorbent is heated by introducing heated gas generated in a hot stove (not shown) into the heating device of the desorption tower 2, and harmful substances such as SOx adsorbed on the carbonaceous adsorbent are removed. Desorb, decompose and regenerate.

Furthermore, the carbonaceous adsorbent is cooled by supplying a cooling medium to a multi-tubular heat exchanger (not shown) below the desorption tower 2 to obtain a reusable carbonaceous adsorbent. Note that sulfur oxide gas such as SO ₂ adsorbed on the carbonaceous adsorbent is desorbed, and the carbonaceous adsorbent is regenerated. Sulfuric acid, sulfur, and the like are recovered from the desorbed sulfur oxide gas by a by-product recovery device (not shown).

  Thereafter, the carbonaceous adsorbent discharged from the desorption tower 2 is conveyed to the sieving machine 7 through the return line 3b. By this sieving machine 7, the carbonaceous adsorbent regenerated in the desorption tower 2 is removed from dust and wear-powdered as it is used. The reusable carbonaceous adsorbent thus obtained is returned to the introduction section 8 of the adsorption tower 30 through the return line 3c and repeatedly used.

  On the other hand, the remainder of the carbonaceous adsorbent after contacting the exhaust gas in the adsorption tower 30 is recovered by the second recovery hopper 17 of the adsorption tower 30 and then circulated to the adsorption tower 30 without going through the desorption tower 2. . That is, the carbonaceous adsorbent which does not need to be recycled is returned to the introduction part 8 of the adsorption tower 30 via the circulation line 4 and reused.

  Below, the effect by the exhaust gas processing apparatus and exhaust gas processing method which concerns on 1st Embodiment is demonstrated.

  First, a sonde (sampling probe) is inserted from the wall surfaces of the front chamber 11a, the middle chamber 11b, and the rear chamber 11c in the adsorption tower 30 by a pilot test apparatus, and the carbonaceous adsorbent is sampled together with collected dust. The results of quantitative analysis of the amount of adsorption and the amount of collected dust are shown in FIG. The horizontal axis in FIG. 3 corresponds to the wall surfaces in the order from the left end to the front chamber 11a, the middle chamber 11b, and the rear chamber 11c, and the vertical axis corresponds to the vertical wall surface of the exhaust gas inlet into which the exhaust gas is introduced.

  As shown in FIG. 3, a desulfurization zone composed of a carbonaceous adsorbent adsorbing a large amount of sulfur oxide (SOx) is distributed in the front chamber and the middle chamber, and a denitration zone that hardly adsorbs SOx is behind. Many rooms are distributed. Although not shown, as a result of sampling soot and dust, the same collection zone distribution as the desulfurization zone was formed.

  That is, the carbonaceous adsorbent adsorbing a large amount of SOx and dust is discharged from the front chamber 11a and the middle chamber 11b shown in FIG. 2, and the carbonaceous adsorbent hardly adsorbing SOx and dust is the rear chamber 11c. Discharged from.

  Therefore, in the present embodiment, the carbonaceous adsorbent adsorbing a large amount of SOx that is recovered by the first recovery hopper 16 and needs to be regenerated in the desorption tower 2 is transferred to the desorption tower 2 by the transfer line 3a. The carbonaceous adsorbent, which is hardly adsorbed by SOx which is recovered by the second recovery hopper 17 and does not need to be regenerated in the desorption tower 2, is circulated to the adsorption tower 30 by a circulation line 4 different from the transport line 3a. I made it.

  Thereby, the regeneration processing amount in the desorption tower 2 of the carbonaceous adsorbent that needs to be constantly regenerated can be increased without increasing the desorption tower 2. Therefore, even when a large amount of exhaust gas treatment is performed, it is possible to reduce pressure loss in the adsorption tower while suppressing an increase in cost. Furthermore, the carbonaceous adsorbent discharged from the rear chamber 11c can be recycled and used without sieving, so that the carbonaceous adsorbent can be used effectively and the wear of the carbonaceous adsorbent can be reduced. Become.

  A specific example will be described below by taking as an example a case where the desorption tower 2 can regenerate the carbonaceous adsorbent for a total amount of 20 tons per hour.

  For example, 5 tons / hour from the front chamber 11a (first reaction chamber) of the adsorption tower 30, 7.5 tons / hour from the middle chamber 11b (first reaction chamber), and every hour from the rear chamber 11c (second reaction chamber). It is assumed that 7.5 tons of carbonaceous adsorbent has been conveyed to the desorption tower 2.

  In this case, if the carbonaceous adsorbent discharged from the rear chamber 11c is circulated to the adsorption tower 30 via the circulation line 4 without passing through the desorption tower 2, the carbon discharged from the front chamber 11a and the middle chamber 11b. Since it is necessary to regenerate only 12.5 t of the adsorbent, the regeneration process can be performed quickly in the desorption tower 2. Further, since the amount of the carbonaceous adsorbent to be regenerated is reduced, it is not necessary to enlarge the desorption tower 2, and it is possible to reduce the consumption of fuel used for heating regeneration. Therefore, even when a large amount of exhaust gas treatment is performed, it is possible to reduce pressure loss in the adsorption tower while suppressing an increase in cost.

Further, as described above, the carbonaceous adsorbent adsorbing a large amount of SOx discharged from the front chamber 11a and the middle chamber 11b needs to be regenerated. On the other hand, the carbonaceous adsorbent is discharged from the rear chamber 11c is dust content, for the amount of adsorption of SO ₂ is small, there is no need to play in the regenerator 2, it is recycled back to the adsorption tower 30 issues Absent.

  Therefore, in the desorption tower 2, the amount of the carbonaceous adsorbent discharged from the front chamber 11a and the middle chamber 11b is regenerated by the amount transported from the rear chamber 11c to the desorption tower 2 (7.5 t / hour). It is possible to increase it.

  In this case, the carbonaceous adsorbent can be sent to the full capacity of the desorption tower 2 by increasing the rotation speed of the roll feeders RF1a and RF1b in the front chamber 11a and the middle chamber 11b. By drawing out the carbonaceous adsorbent (dust) from the adsorption tower 30 in this way, the pressure loss in the adsorption tower 30 can be reduced as quickly as possible.

  Further, by controlling the rotation speeds of the roll feeder RF1a in the front chamber 11a, the roll feeder RF1b in the middle chamber 11b, and the roll feeder RF2 in the rear chamber 11c, the carbon in the front chamber 11a, the middle chamber 11b, and the rear chamber 11c is controlled. The moving speed of the adsorbent can be adjusted.

  In addition, as a transfer amount of the carbonaceous adsorbent, for example, the ratio of the front chamber 11a is 20 to 25% with respect to the whole (the front chamber 11a, the middle chamber 11b, the rear chamber 11c), and the ratio of the middle chamber 11b is with respect to the whole. 50 to 60%, and the ratio of the rear chamber 11c can be selected to be 20 to 25% of the whole. That is, the transfer amount of the carbonaceous adsorbents required for regeneration discharged from the front chamber 11a and the middle chamber 11b corresponds to 75 to 80% of the total, and the carbonaceous adsorbents required for regeneration are sent to the desorption tower 2. After being regenerated, it is returned to the adsorption tower 30. Therefore, the regeneration-free carbonaceous adsorbent discharged from the rear chamber 11c is 20 to 25% of the regenerated carbonaceous adsorbent supplied from the desorption tower 2. The rate at which this regeneration-necessary adsorbed carbonaceous material reaches the rear chamber 11c again is about 6.3% at the maximum, so there is little possibility that accumulation of sulfur oxide (SOx) will be a problem.

(Second Embodiment)
Hereinafter, an exhaust gas treatment apparatus according to the second embodiment will be described.

  The exhaust gas treatment apparatus according to the second embodiment is the same as that of the first embodiment except that the exhaust gas treatment apparatus according to the first embodiment is further provided with a switching unit.

  FIG. 4 shows an exhaust gas treatment apparatus 400 according to the second embodiment. As shown in FIG. 4, a switching unit SW2 is provided between the opening / closing valve V3 of the adsorption tower 30 and the transfer line 3a.

  That is, the second recovery hopper 17 of the adsorption tower 30 can switch the connection between the transport line 3a and the circulation line 4 by selecting the switching unit SW2.

  The switching unit SW2 includes a three-way valve or a diverter, and the operation may be performed manually or may be performed automatically by a computer or the like.

  Next, an exhaust gas treatment method according to the second embodiment will be described.

[Operation at low pressure loss]
First, the low pressure loss operation will be described with reference to FIG.

  In the initial stage of the exhaust gas treatment operation, there is little clogging of harmful substances in the adsorption tower 30, and the pressure loss is low. At the time of such a low pressure loss that the pressure loss in the adsorption tower 30 is less than a predetermined first threshold value, the following operation at the low pressure loss is performed. The pressure loss is measured by using a pressure gauge to determine the difference (decrease) in air pressure (static pressure) generated between the exhaust gas inlet 14 and the exhaust gas outlet 15 of the adsorption tower 30 shown in FIG.

  First, as shown in FIG. 4, the switching unit SW2 selects the transport line 3a. In this case, the carbonaceous adsorbent after contacting the exhaust gas in the adsorption tower 30 is recovered from the first recovery hopper 16 and the second recovery hopper 17 of the adsorption tower 30, respectively, and then desorbed via the transport line 3a. Transport to the separation tower 2. Then, after the carbonaceous adsorbent sent to the desorption tower 2 is heated and regenerated, it is cooled and discharged. Thereafter, the carbonaceous adsorbent discharged from the desorption tower 2 is conveyed to the sieving machine 7 through the return line 3b. In the sieving machine 7, the carbonaceous adsorbent regenerated in the desorption tower 2 is removed from dust and those that are worn and powdered with use. The reusable carbonaceous adsorbent thus obtained is returned to the introduction section 8 of the adsorption tower 30 through the return line 3c and repeatedly used.

[Operation at high pressure loss]
Next, operation during high pressure loss will be described with reference to FIG. FIG. 5 shows an exhaust gas treatment apparatus 500 according to the second embodiment.

  When the exhaust gas treatment operation is continued, harmful substances are clogged in the adsorption tower 30 and the pressure loss increases. At the time of such a high pressure loss that the pressure loss in the adsorption tower 30 is equal to or higher than a predetermined first threshold value, the following operation at the time of high pressure loss is performed.

  First, as shown in FIG. 5, the switching unit SW2 selects the circulation line 4. In this case, the carbonaceous adsorbent that comes into contact with the exhaust gas in the adsorption tower 30 and is discharged from the front chamber 11a and the middle chamber 11b and recovered by the first recovery hopper 16 is transferred to the desorption tower 2 via the transport line 3a. Transport. The carbonaceous adsorbent conveyed to the desorption tower 2 is heated and regenerated, and then cooled and discharged. Thereafter, the carbonaceous adsorbent discharged from the desorption tower 2 is conveyed to the sieving machine 7 through the return line 3b. In the sieving machine 7, the carbonaceous adsorbent regenerated in the desorption tower 2 is removed from dust and those that are worn and powdered with use. The reusable carbonaceous adsorbent thus obtained is returned to the introduction section 8 of the adsorption tower 30 through the return line 3c and repeatedly used.

  On the other hand, the carbonaceous adsorbent that comes into contact with the exhaust gas in the adsorption tower 30 and is discharged from the rear chamber 11 c and collected by the second collection hopper 17 is circulated to the adsorption tower 30 without passing through the desorption tower 2. That is, the carbonaceous adsorbent which does not need to be recycled is returned to the introduction part 8 of the adsorption tower 30 via the circulation line 4 and reused.

  Thereafter, when the pressure loss in the adsorption tower 30 falls below the second threshold value which is smaller than the first threshold value, the selection of the switching unit SW2 is returned from the circulation line 4 to the transfer line 3a, thereby returning to the operation at the time of low pressure loss. It is also possible.

  For example, when the limit value of the pressure loss in the adsorption tower 30 is 5 kPa, for example, 4 kPa to 4.5 kPa is selected as the first threshold value lower than the limit value, and further lower than the first threshold value. For example, 2 kPa to 3 kPa is selected as the second threshold value.

  The effects of the exhaust gas treatment device and the exhaust gas treatment method according to the second embodiment will be described below.

  According to the exhaust gas treatment apparatus and the exhaust gas treatment method according to the second embodiment, when the pressure loss in the adsorption tower 30 is sufficiently low, the low pressure loss operation is performed, and all the carbonaceous adsorbent is passed through the desorption tower 2. Thus, it can be circulated through the adsorption tower 30. And when the pressure loss in the adsorption tower 30 becomes high, operation at the time of high pressure loss is performed, and the conveyance of the carbonaceous adsorbent discharged from the second recovery hopper 17 is carried by the conveyance line 3a and the return lines 3b, 3c. Can be switched to the circulation line 4. As a result, the amount of the medium discharged from the first recovery hopper 16 and needing regeneration in the desorption tower 2 by the amount of the medium discharged from the second recovery hopper 17 and unnecessary to be regenerated in the desorption tower 2 is recovered. It is possible to increase the amount of reproduction processing. Therefore, when the pressure loss in the adsorption tower 30 increases while suppressing an increase in cost, the pressure loss can be selectively reduced.

  Furthermore, when the pressure loss is reduced to the second threshold value, it is possible to perform switching again to return to the operation at the time of low pressure loss. Thereby, even if the pressure loss rises again with the passage of the exhaust gas treatment time, the exhaust gas treatment can be suitably continued until the pressure loss in the adsorption tower 30 rises to at least the first threshold value. .

(Third embodiment)
Hereinafter, an exhaust gas treatment apparatus according to the third embodiment will be described.

  The exhaust gas treatment apparatus according to the third embodiment is the same as that of the second embodiment except that the circulation line of the exhaust gas treatment apparatus according to the second embodiment is changed to a backup line and a switching unit SW1 is added.

  FIG. 6 shows an exhaust gas treatment apparatus 600 according to the third embodiment. As shown in FIG. 6, a switching unit SW1 is provided between the opening / closing valve V2 of the adsorption tower 30 and the transfer line 3a. The switching unit SW1 includes a three-way valve or a diverter, and the operation may be performed manually or may be performed automatically by a computer or the like. In addition to the transfer line 3a, a backup line BL1 is provided at the tip of the switching unit SW1, and the switching unit SW1 can switch the selection between the transfer line 3a and the backup line BL1. Similarly, a switching unit SW2 is provided between the opening / closing valve V3 of the adsorption tower 30 and the transport line 3a. In addition to the transfer line 3a, a backup line BL2 is provided at the tip of the switching unit SW2, and the switching unit SW2 can switch the selection between the transfer line 3a and the backup line BL2.

  The backup lines BL1 and BL2 are connected to the backup line BL. A backup line BL3 is provided between the backup line BL and the introduction part 8 (shown in FIG. 2) of the adsorption tower 30. A backup line BL4 is provided between the backup line BL and the opening / closing valve V4 of the desorption tower 2. Further, a backup line BL5 is provided between the backup line BL and the opening / closing valve V5 of the desorption tower 2, and a backup line BL6 is provided between the downstream side of the sieving machine 7 and the backup line BL. It has been.

  The backup lines BL and BL1 to 6 are conveyors such as conveyors, and examples thereof include belt conveyors and bucket conveyors. From the viewpoint of suppressing an increase in cost, it is preferable to use a belt conveyor for the backup lines BL, BL1 to BL6.

  Next, an exhaust gas treatment method according to the third embodiment will be described.

〔Normal time〕
First, an exhaust gas treatment method in a normal time will be described. During normal times when the transfer line 3a and the return line 3c can be operated normally, the exhaust gas treatment method similar to the low pressure loss operation described in the second embodiment is performed.

[When the transport line 3a fails]
Next, an exhaust gas treatment method when the transfer line 3a fails due to damage or the like will be described. In this case, the selection of the switching units SW1 and SW2 is switched from the transport line 3a to the backup lines BL1 and BL2, respectively.

  As a result, the carbonaceous adsorbent discharged from the adsorption tower 30 is merged with the backup line BL via the backup lines BL1 and BL2, and then conveyed to the desorption tower 2 via the backup line BL4. The carbonaceous adsorbent heated and regenerated in the desorption tower 2 is returned to the adsorption tower 30 via the return lines 3b and 3c and can be reused.

[When the sieve 7 connected to the return line 3b fails]
Next, an exhaust gas treatment method in the case where the sieving device 7 connected to the return line 3b fails due to damage or the like will be described. In this case, the carbonaceous adsorbent discharged from the desorption tower 2 is transferred to the backup line BL via the backup line BL5 and then returned to the adsorption tower 30 via the backup line BL3 so that it can be reused. .

[When return line 3c fails]
Finally, an exhaust gas treatment method in the case where the return line 3c fails due to damage or the like will be described. In this case, the carbonaceous adsorbent discharged from the sieving machine 7 is transported to the backup line BL via the backup line BL6 and then returned to the adsorption tower 30 via the backup line BL3 so that it can be reused.

  The effects of the exhaust gas treatment device and the exhaust gas treatment method according to the third embodiment will be described below.

  In addition to the effects described in the second embodiment, when at least one of the transfer line 3a, the return line 3b, and the return line 3c of the exhaust gas treatment device fails due to damage or the like, the backup lines BL and BL1 to 6 are substituted. Thus, the exhaust gas treatment operation can be continued.

It is a schematic diagram which shows the structure of the waste gas processing apparatus which concerns on 1st Embodiment. It is a schematic cross section which shows the structure of the reaction chamber which concerns on this invention. It is a figure which shows the result of having sampled and measured the deposit | attachment to the adsorption tower 30 wall surface. It is a schematic diagram which shows the structure of the waste gas processing apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the structure of the waste gas processing apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the structure of the waste gas processing apparatus which concerns on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Adsorption equipment, 2 ... Desorption tower, 3a ... Conveyance line, 3b, 3c ... Return line, 4 ... Circulation line, 5 ... Receiving hopper, 6 ... Storage tank, 7 ... Sieving machine, 8 ... Introduction part, 16 ... First One recovery hopper, 17... Second recovery hopper, 30... Adsorption tower, 100, 400, 500, 600.

Claims (5)

In exhaust gas treatment equipment that removes harmful substances in exhaust gas with a medium,
An adsorption tower for containing the medium and removing the harmful substances by passing the exhaust gas through the medium;
A desorption tower for regenerating the medium having reduced activity;
A transport line for transporting the medium discharged from the adsorption tower to the desorption tower;
A return line for returning the medium regenerated in the desorption tower to the adsorption tower;
A circulation line for returning the medium discharged from the adsorption tower to the adsorption tower,
The adsorption tower includes an introduction part into which the medium is introduced, a first reaction chamber located upstream in the exhaust gas flow direction, a second reaction chamber located downstream in the exhaust gas flow direction, and the first A first recovery hopper for recovering the medium discharged from one reaction chamber, and a second recovery hopper for recovering the medium discharged from the second reaction chamber;
The introduction part of the adsorption tower is connected to the return line and the circulation line;
The first recovery hopper of the adsorption tower is connected to the transport line;
Wherein the second recovery hopper of the adsorption tower, the is connected to the circulation line and the conveying line, exhaust gas treatment, it characterized the next possible to switch between the connection between the transport line and the circulation line apparatus. When the pressure loss in the adsorption tower is less than a predetermined first threshold, the connection of the second recovery hopper is switched to the transfer line, and the pressure loss in the adsorption tower is The exhaust gas treatment apparatus according to claim 1, further comprising a switching unit that switches connection of the second recovery hopper to the circulation line when the value is equal to or greater than a threshold value . In the exhaust gas treatment method using the exhaust gas treatment device according to claim 1,
The medium recovered by the first recovery hopper is transported to the desorption tower via the transport line and regenerated, and the regenerated medium is returned to the adsorption tower via the return line,
An exhaust gas treatment method, wherein the medium recovered by the second recovery hopper is returned to the adsorption tower through the circulation line. In the exhaust gas treatment method using the exhaust gas treatment device according to claim 1 ,
When the pressure loss in the adsorption tower is less than a predetermined first threshold, the medium recovered by the first and second recovery hoppers is transported to the desorption tower via the transport line. Regenerating and performing the operation at low pressure loss to return the regenerated medium to the adsorption tower through the return line,
When the pressure loss in the adsorption tower becomes equal to or higher than the first threshold, the medium recovered by the first recovery hopper is transported to the desorption tower via the transport line and regenerated, and the regenerated medium Is returned to the adsorption tower via the return line, and the medium recovered by the second recovery hopper is returned to the adsorption tower via the circulation line for high pressure loss operation. Exhaust gas treatment method.   When the pressure loss in the adsorption tower is equal to or higher than the first threshold, the high pressure loss operation is performed until the pressure loss in the adsorption tower falls below a second threshold that is smaller than the first threshold. The exhaust gas treatment method according to claim 4.

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