JP2006326430A - Absorbing tower for flue gas desulfurization apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbing tower for a flue gas desulfurization apparatus capable of effectively resolving settlement and deposition problems of solid in a liquid sump tank with less facility cost and energy consumption. <P>SOLUTION: Agitation units 21 for swirling gypsum slurry A in are provided at the outer circumference of the liquid sump tank 20, and a unit for increasing the flow rate of the gypsum slurry A is provided near the central part of the liquid sump tank 20. A piping system 50 is provided as a means for increasing the flow speed of the gypsum slurry A near the central part, taking out part of the gypsum slurry A from the discharge side of a circulation pumps 32 and jetting through multiple ejectors 54 in the liquid sump tank 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The invention according to claim relates to an absorption tower of a flue gas desulfurization apparatus in which flue gas (exhaust gas) and gypsum slurry are brought into contact with each other in an upper gas-liquid contact area and the gypsum slurry is stored in a lower liquid tank. is there.

As a flue gas desulfurization apparatus which is an environmental countermeasure facility such as a power plant, an absorption tower 1 ′ having a format as shown in FIG. 6 is generally used. As shown in FIG. 6 (a), the absorption tower 1 ′ has a gas-liquid contact area (absorption zone) 10 for absorbing and removing SO ₂ in the exhaust gas by injecting spray water into the exhaust gas to be introduced. The liquid reservoir tank 20 for storing the slurry used as spray water is provided in the lower part. Reference numeral 12 in the figure denotes a partition plate for forming an exhaust gas passage, reference numeral 14 denotes a spray nozzle, and reference numeral 32 denotes a slurry circulation pump. In the liquid storage tank 20, air is blown into the liquid and limestone is supplied to oxidize the slurry that has absorbed SO ₂ and to neutralize the sulfuric acid produced thereby. By doing so, gypsum (CaSO ₄ .2H ₂ O) can be obtained as a by-product in the liquid storage tank 20.

The above process in the flue gas desulfurization apparatus is represented by the following reaction formula. That is,
Absorption reaction: SO ₂ + H ₂ O → H ₂ SO ₃
Oxidation reaction: H ₂ SO ₃ + 1 / 2O ₂ → H ₂ SO ₄
Neutralization reaction: CaCO ₃ + H ₂ SO ₄ + H ₂ O → CaSO ₄ .2H ₂ O + CO ₂

  Although the gypsum slurry is stored in the liquid tank 20 by the above, in the liquid tank 20 for the purpose of promoting the neutralization reaction and preventing the solid matter such as gypsum from settling and depositing on the bottom. Conventionally, a stirring means for rotating the gypsum slurry is arranged. In the example of FIG. 6, a plurality of propeller-type horizontal stirrers 21 are attached to the outer wall of the liquid reservoir 20 as shown in FIG. Each stirrer 21 is provided with a slight inclination in the specific direction from the central portion of the liquid storage tank 20 with respect to the center line (direction of the generated flow). Thus, a swirl flow is formed.

The stirring means generally used is a horizontal stirrer as described above (see FIG. 6), and there are Patent Documents 1 and 2 listed below as means for further improving the stirring power. In the example of Patent Document 1, different types of stirrers are arranged separately on the upper and lower portions of the outer wall of the liquid storage tank. In the example of Patent Document 2, a stirrer 21 is provided on the outer wall of the liquid reservoir 20 as in the apparatus 1 ″ of FIG. 7, and the liquid dropping motion is horizontally between the gas-liquid contact area 10 and the liquid reservoir 20. By attaching the vane 28 having the function of converting the motion into the direction, the swirl flow by the stirrer 21 is strengthened.
JP-A-62-71520 JP 2002-248318 A

  When the stirring means (stirrer 21) is provided on the outer wall of the liquid storage tank as shown in FIG. 6, solid matter X ′ such as gypsum is likely to settle and deposit near the center of the liquid storage tank 20. This is because the speed of the swirling flow formed tends to be insufficient near the center even if it is high near the outer periphery. As the apparatus becomes larger and the diameter of the liquid reservoir 20 becomes larger, the amount of solid matter X 'deposited near the center generally increases.

The following problems arise when the amount of solid deposits increases. That is, the effective capacity of the liquid storage tank is reduced by the accumulated solid matter, the progress of the oxidation reaction / neutralization reaction becomes insufficient, the unreacted H ₂ SO ₃ remains, or the unreacted CaCO ₃ becomes gypsum. Many remain in it. As a result, desulfurization performance may be deteriorated, or high-quality gypsum may not be obtained as a by-product. In addition, when inspecting the bottom of the liquid storage tank by periodic inspection (inspecting the soundness of the lining, etc. inside the absorption tower), it is necessary to remove the deposit and to treat the removed deposit. Time, labor, and expense are required.

  If the strong swirl flow is generated by increasing the number and capacity of the stirring means provided near the outer periphery, the above-mentioned problems can be solved. In this case, however, considerable equipment cost and energy (electric power, etc.) are required for the stirring means. I need it. This is because the entire gypsum slurry must be swirled so as to have a sufficient flow rate even near the center of the liquid reservoir.

  In the example of Patent Document 1 as well, since the stirring means is provided only near the outer periphery of the liquid reservoir, in order to prevent the settling and accumulation of solid matter near the center, a considerably large capacity or a large number of stirring means is required. As they are deployed, they need to consume considerable energy.

  On the other hand, in the example of Patent Document 2 (see FIG. 7), although the swirl flow by the stirring means is strengthened by the action of the vane, a considerable equipment cost is required to provide the vane in the upper part of the liquid reservoir. Become. The vane needs to be a large member that covers almost the entire reservoir tank, and it is also resistant to wear and corrosion so that it will not be worn or corroded by the gypsum slurry that falls from the reservoir tank to the gas-liquid contact area. This is because processing for granting is necessary.

  The claimed invention has been made to solve the above-described problems, and is capable of effectively eliminating the sedimentation and accumulation of solid matter in the liquid storage tank with a small equipment cost and a small amount of energy consumption. An absorption tower of a smoke desulfurization apparatus is provided.

The invention according to the claim relates to an absorption tower of a flue gas desulfurization apparatus of a type in which gypsum slurry is accumulated in a liquid storage tank and circulated between the upper gas-liquid contact area using a pump.
a) Stirring means for swirling the gypsum slurry inside the liquid storage tank (regardless of type, for example, liquid or gas jetted from a nozzle or liquid sent by a propeller, etc.) Near the outer periphery (region along the outer wall),
b) Means for increasing the flow rate of the gypsum slurry near the center in the vicinity of the center of the liquid reservoir (the portion along the vertical center line and the vicinity thereof, that is, the region farthest from the outer periphery). This is characterized in that liquid or gas is ejected from the nozzle, or liquid is sent by a propeller or the like.

  In this absorption tower, a swirling flow is generated in the liquid storage tank using the stirring means shown in the above a), and the flow velocity near the center of the liquid storage tank is locally increased using the means shown in the above b). By both, a flow having a certain speed or more is formed near the outer periphery or near the center in the liquid storage tank, so that a large amount of solid matter can be prevented from being settled and deposited in any part including the vicinity of the center. Therefore, the effective capacity of the liquid storage tank due to the accumulated solids does not decrease, the oxidation reaction / neutralization reaction proceeds sufficiently, the desulfurization performance is improved, and high-quality gypsum can be obtained as a by-product. It is done. Regular inspections of the bottom of the liquid reservoir can be easily performed in a short time.

  In addition, the entire gypsum slurry in the liquid reservoir containing the vicinity of the center is not swirled integrally, but only the vicinity of the center where the flow velocity tends to be insufficient among the swirling flow formed by the stirring means a) is b. ), The speed is increased, so that a large-capacity facility is unnecessary and energy consumption can be reduced. In addition, it is not necessary to use a large member that covers the entire liquid storage tank, and it is not necessary to modify or add to the stirring means near the outer periphery. Easy to do.

  In the above absorption tower, a propeller-type horizontal stirrer is provided as a stirring means for swirling the gypsum slurry, and as the above means for increasing the flow rate of the gypsum slurry near the center, one is provided from the outlet side (discharge side) of the pump. It is particularly preferable to provide a pipeline system for taking out the gypsum slurry of the part and ejecting it from a plurality of ejectors in the liquid reservoir. As is well known, an ejector is an ejection means in a form in which a fluid ejected from a nozzle entrains surrounding fluid and ejects it from a diffuser.

In this way, equipment costs and energy consumption are particularly effectively suppressed. This is because the propeller-type horizontal stirrer can efficiently swivel the gypsum slurry with less equipment cost. Furthermore, the above-mentioned pipeline system as a means for increasing the flow rate of the gypsum slurry near the center is similar to the above. This is because it has a particularly advantageous effect on the surface.
That is, the pipeline system first takes out a part of the gypsum slurry from the outlet side of the pump and ejects it into the liquid reservoir, and does not require a dedicated pump or the like. In addition, the required amount of gypsum slurry to be taken out in order to locally increase the flow velocity in the vicinity of the center of the liquid tank is generally much higher than the capacity of the pump that circulates the gypsum slurry in the liquid tank between the gas-liquid contact area. Since the amount is small, there is almost no influence of such removal on the capacity of the pump and the progress of the absorption reaction in the gas-liquid contact area.
Secondly, the pipeline system also has an advantageous effect in that gypsum slurry is ejected from an ejector rather than a simple nozzle. If it is a mere nozzle, only the same amount of gypsum slurry as that taken out from the outlet side of the pump will be ejected, but if an ejector is used, the surrounding gypsum slurry will also be entrained and a larger amount than the diffuser (amount taken out) (3-4 times greater than that), it is clearly effective in increasing the flow velocity.

  The upstream end (that is, the outlet) of the pipeline system for taking out the gypsum slurry is provided with a horizontal portion having an enlarged pipe diameter (expanded from the diameter of the pump outlet portion) on the outlet side (discharge side) of the pump. It is preferable to connect to the upper part of the horizontal part.

  By doing so, it is difficult for the solid matter to flow into the above-described pipeline system leading to the ejector, and thus the ejector is prevented from being blocked. This is because if a horizontal part with an enlarged pipe diameter is provided on the outlet side of the pump, the gypsum slurry has a low flow velocity in the pipe and solids mainly flow in the lower part, so that there is little solids in the upper part of the part. That is, gypsum slurry with less solid matter is sent to the above pipe line system from the upper part of the horizontal part with an enlarged pipe diameter on the outlet side of the pump.

Of the above ejectors, the nozzle and diffuser are made of ceramic, or the inner surface is lined with wear-resistant rubber or resin (for example, a metal such as stainless steel or FRP as a base material, the inner surface, etc. It is recommended to use the one with such a lining.
Since the gypsum slurry flows inside the ejector at a high flow rate, when the nozzle or diffuser is formed of a general metal, there is a possibility that it will be corroded and worn out and lose its durability in a short time. In that regard, if the nozzle is formed of ceramic as described above, or if the inner surface is made of a material that is lined with wear-resistant rubber or resin, it will be long enough to provide sufficient corrosion resistance and wear resistance. It becomes possible to continue using the period.

The bottom plate of the liquid storage tank is preferably subjected to wear-resistant lining including the vicinity of the center.
In the absorption tower of the present invention, the gypsum slurry swirls in the liquid tank, and the flow velocity is high even near the center. Therefore, if such a lining is not provided, long-term use becomes impossible due to wear. .

The above-mentioned means for increasing the flow rate of the gypsum slurry near the center is arranged so as to generate a flow from the center of the liquid storage tank to the outside and obliquely downward, and at the center of the bottom of the liquid storage tank, a conical or truncated cone It is particularly preferable to form a cone (protrusion) that bulges upward in a shape and wear-resistant lining the upper surface of the cone.
Even if the means for increasing the flow rate of the gypsum slurry near the center is provided as described above, a sufficient flow rate is unlikely to occur in the central portion of the liquid reservoir, and solid deposits tend to occur somewhat. However, if the direction of the means for increasing the flow rate is set as described above and the cone as described above is formed at the center of the bottom of the liquid reservoir, solid deposition is hardly generated at the center. This is because accumulation is generally difficult to occur on the inclined surface of the cone, and the flow by the above-mentioned means for increasing the flow velocity follows the surface of the cone, so that it is difficult for solids to settle on and near the surface of the cone. .

The direction of the increase in flow rate in the above means for increasing the flow rate of the gypsum slurry near the center (if not limited to a specific direction, the direction in which the flow rate is highest) refers to the speed component in the turning direction by the stirring means. It is recommended that it be included.
By doing so, the swirling flow formed in the liquid storage tank by the stirring means is also strengthened by the increase in flow velocity caused by the above means for increasing the flow velocity near the center, so that a strong swirling flow is applied to the entire liquid storage tank. Is easily formed. When the swirl flow is strengthened as a whole, the flow velocity is improved as a whole, including the center of the liquid reservoir and parts close to it, so that it is easy to prevent sedimentation and accumulation of solids in the entire area of the liquid reservoir. The neutralizing action of is promoted.

  According to the absorption tower described in the claims, a flow of gypsum slurry having a speed equal to or higher than a certain rate is formed near the outer periphery and near the center in the liquid reservoir, and a large amount of solid matter is present in any part including the vicinity of the center. Sedimentation and deposition are prevented. As a result, the work of removing the solid matter accumulated at the bottom of the absorption tower during the periodic inspection is greatly reduced, and the periodic inspection period can be shortened and the processing cost can be reduced. Moreover, since the entire gypsum slurry in the liquid storage tank is not swirled integrally, a large-capacity facility is unnecessary and energy consumption can be reduced. Further, it is not necessary to use a special large member, and it is not necessary to modify or add a stirring means in the vicinity of the outer periphery. Therefore, the existing apparatus can be easily modified and configured at low cost.

  As a means of increasing the flow rate of the gypsum slurry near the center, if a pipe system is provided that takes out a part of the gypsum slurry from the outlet side (discharge side) of the pump and ejects it from a plurality of ejectors in the reservoir, the equipment costs And is particularly advantageous in terms of energy consumption. This is because it is not necessary to provide a dedicated pump or the like for the means, and a large amount of ejection can be obtained by the action of the ejector.

  In particular, when applied to an existing absorption tower, it is not necessary to increase the capacity of the stirrer or install a new stirrer, and it is sufficient to supply a small amount of absorbent slurry to the ejector compared with the circulation flow rate of the absorption tower. Therefore, there is almost no increase in running cost.

  In addition, if the material of each part is determined or the lining is applied as described in any claim, the service life of the apparatus is extended and long-term use becomes possible. Further, if the direction of the ejector or the like is determined and the cone is formed as described in the claims, the accumulation of solid matter in the central portion of the liquid reservoir is more effectively prevented. In addition, if the direction of the ejector, etc. is determined appropriately, the flow rate of the liquid reservoir is improved as a whole and the stirring effect is improved. As a result, there are further advantages in terms of preventing solids accumulation and promoting neutralization / oxidation. It is.

  One form regarding implementation of invention is shown in FIGS. 1 is a longitudinal sectional view showing the entire absorption tower 1 of the flue gas desulfurization apparatus, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is a plan view showing details of the structure near the center of FIG. 3 (a)) and a side view (same (b)). FIG. 4 is a detailed view showing the upstream end (outlet) 51 of the pipe line system 50 leading to the ejector 54. FIG. 5 is a diagram showing a state of deposition of the solid substance X in the liquid storage tank 20 when the ejector 54 or the like is used. FIG. 5 (a) is a plan view (same (a)), and FIG. It is a bb sectional view in).

As shown in FIG. 1, the absorption tower 1 is provided with a gas-liquid contact area 10 in an upper part inside a casing 2 formed in a substantially cylindrical shape, and a liquid storage tank 20 in a lower part thereof. The gypsum slurry A is stored in the liquid storage tank 20, and is supplied to the gas-liquid contact area 10 through a circulation pipe 30 including a circulation pump 32, and sprayed from a large number of spray nozzles 14 arranged there. On the other hand, exhaust gas (smoke) from a boiler or the like is introduced into the same gas-liquid contact area 10. The exhaust gas is introduced from the inlet duct 11 and sent along the partition plate 12 in the gas-liquid contact area 10 in a specific direction, where it is brought into contact with the gypsum slurry spray and discharged from the outlet duct 13. Due to the gas-liquid contact between the exhaust gas and the slurry, the exhaust gas is absorbed and removed by most of the sulfur oxide (SO ₂ ) and discharged from the outlet duct 13, and the slurry absorbs SO ₂ in moisture and then is liquid. Return to the reservoir 20. The pH of the slurry A in the liquid reservoir 20 is around 5.

Reference numeral 15 in FIG. 1 denotes a support column that stands in the center of the bottom 2a of the casing 2 and supports the spray nozzle 14, the air blowing pipe 22 shown in FIG. 3, the ejector 54 described later, and the like. It is. The blowing pipe 22 blows air into the liquid storage tank 20 to oxidize the slurry A that has absorbed SO ₂ , and reference numeral 23 denotes the blowing nozzle. The extraction pump 42 (described later) is a pump for extracting the generated gypsum out of the absorption tower.
Although not shown in the drawing, the liquid tank 20 is connected with a slurry inlet pipe for neutralizing sulfuric acid produced by oxidizing the slurry A.

  The circulation pipe 30 that circulates the gypsum slurry between the liquid reservoir 20 and the gas-liquid contact area 10 is configured by connecting the following equipment and members. That is, a plurality of suction pipes 31 each having a suction nozzle 31a (see FIG. 2) attached to the side wall (outer wall) of the liquid storage tank 20, a plurality of circulation pumps 32 connected thereto, and outlets of the pumps 32 were connected. A discharge pipe 33, a horizontal header 34 in which a plurality of discharge pipes 33 are connected in parallel, and a supply pipe 35 extending from the horizontal header 34 to the spray 14 are connected. Since the horizontal header 34 collects the slurry sent from the plurality of discharge pipes 33, as shown in FIG. 4, a pipe having a diameter considerably larger than the discharge pipe 33 (for example, about 1 m inside diameter) (for example, about 2 m inside diameter). It is formed by.

  As shown in FIGS. 1 and 2, a plurality of propeller-type horizontal stirrers 21 are arranged on the side wall of the liquid tank 20 to generate a swirling flow of the gypsum slurry A in the liquid tank 20. Each of the stirrers 21 has a drive source 21 a such as a motor outside the liquid reservoir 20, and is equipped with a propeller at the end of a horizontal drive shaft extending to the inside of the liquid reservoir 20. Since all of the agitators 21 are attached by tilting the drive shaft and the propeller center line in a specific direction (slightly toward the left from the center of the liquid reservoir 20 as shown in FIG. 2), the slurry A in the liquid reservoir 20 Thus, a swirling flow in the direction of the arrow (clockwise as viewed from above) is generated. By generating the swirling flow in this manner, the sedimentation / deposition of solid matter in the liquid storage tank 20 is reduced, and the neutralization reaction and the like are promoted. Flake glass lining (FGL) is applied to the bottom 2a and the side wall of the casing 2 in order to prevent wear and corrosion due to the swirling flow.

  With only the swirl flow by the horizontal stirrer 21, in general, a sufficient flow velocity is unlikely to occur near the center of the liquid storage tank 20, and therefore solid matter mainly composed of gypsum tends to accumulate in the vicinity thereof. Therefore, in the illustrated absorption tower 1, the flow rate of the gypsum slurry A in the vicinity of the center of the liquid reservoir 20 is increased as follows.

  That is, as shown in FIG. 3B and the like, a plurality of (in the example shown in the figure) with the spray destination directed outward and obliquely downward at a height near the center of the liquid reservoir 20 and immersed in the gypsum slurry A liquid. Six) ejectors 54 were attached. Each ejector 54 is incorporated in a conduit system 50 including a straight tube 52 for supplying slurry and an annular tube 53 to which all the ejectors 54 are attached at intervals. It is fixed.

  Each ejector is composed of a nozzle part and a diffuser part. The ejector takes in the surrounding liquid by a high-speed flow ejected from the nozzle part, and discharges a flow rate about three times the supply flow rate from the diffuser part. FRP with high corrosion resistance is used as the material of the ejector, and further, lining with high corrosion resistance and wear resistance is applied to the inside of the nozzle portion and the diffuser portion in order to prevent wear due to slurry having a high flow rate.

  Supply of the fluid to the ejector 54 performed via the pipeline system 50 is not performed by a dedicated pump, but is performed using the circulation pump 32 in the circulation pipe 30 shown in FIG. That is, the upstream end 51 of the pipe line system 50 is connected to the outlet side (discharge side) of the circulation pump 32 in the circulation pipe 30, and a part of the gypsum slurry sent to the gas-liquid contact area 10 is taken out to each ejector 54. Supply. The amount of slurry supplied to the ejector 54 is determined based on the fact that the flow rate near the center of the bottom of the liquid reservoir 20 is equal to or higher than the sedimentation rate of the solid matter. In order to increase the flow velocity in this way for the local gypsum slurry A limited to the vicinity of the center of the liquid reservoir 20, it is sufficient to supply a small amount of slurry to each ejector 54 as a driving fluid. Since the amount thereof is about 0.3% of the circulation flow rate through the circulation pipe 30, the removal of the gypsum slurry by the pipe line system 50 has no possibility of affecting the original circulation and desulfurization reaction of the slurry.

  In the circulation pipe 30, as described above, the horizontal header 34 that is a large-diameter horizontal pipe portion is provided on the outlet side of the circulation pump 32. The upstream end (outlet) 51 of the pipe line system 50 reaching the ejector 54 is connected to a part of the horizontal header 34 in the circulation pipe 30 as shown in FIGS. More specifically, the upstream end 51 of the pipeline system 50 is a portion of the horizontal header 34 where a large amount of slurry from the discharge pipe 33 to the supply pipe 35 is not merged (ie, for example, one of the headers 34). When counting the number of connection locations of the discharge pipe 33 from the end portion 34a toward the connection portion of the supply pipe 35, the number of connection locations between the end portion 34a and the upstream end 51 of the pipeline system 50 is 1 or less. And a portion that can be said to be the uppermost portion (or the vicinity thereof) of the horizontal header 34. Since the header 34 has a large diameter, the internal flow velocity is low. However, in the above portion, the flow velocity is particularly low due to the combined flow rate, so the solid matter in the slurry mainly flows in the lower part of the pipeline, and the uppermost portion. This is because a liquid with a small amount of solids is supplied to the pipeline system 50 at a location close to. When a slurry containing a small amount of solids is supplied to the pipeline system 50, blockage of the flow path is difficult to occur in the pipeline system 50, and the nozzle portion of the ejector 54 that is most thin and easily clogged. The slurry is continuously sprayed.

  As described above, each of the ejectors 54 directs the ejection destination to the outside and obliquely downward (see FIG. 3B). As the direction shown in the plan view, each ejection destination is set as shown in FIG. 3A. Inclined by an angle θ to the right with respect to the base (upstream end). That is, the speed component of the direction along the swirl flow by the horizontal stirrer 21 shown in FIG. 2 is included in the increase in the flow velocity of the slurry A by the ejector 54. Thereby, the swirling flow of the slurry A formed in the liquid storage tank 20 by the horizontal stirrer 21 is strengthened, and the accumulation of solid matter is easily prevented throughout the liquid storage tank 20.

  Further, as shown in FIG. 3, in the vicinity of the central portion of the liquid reservoir 20, an upward cone 24 having a truncated cone shape is formed between the bottom 2 a and the support column 15. The cone 24 is also a member for reinforcing the base portion of the support column 15, but also exhibits a function of preventing the accumulation of solid substances in the center of the liquid reservoir 20 in combination with the action of the flow of the slurry A by the ejector 54. In general, deposition does not easily occur on the inclined surface of the cone 24, and the flow by the ejector 54 follows the inclined surface, so that solids hardly deposit on the surface of the cone 24 and the vicinity thereof. Since it is in contact with the flow by the ejector 54, the surface of the cone 24 and its periphery are provided with a lining excellent in wear resistance.

  In the illustrated absorption tower 1 of FIG. 1, the slurry can be supplied to the ejector 54 also from the outlet pipe (extraction pipe 40) of the extraction pump 42. This is because when the liquid level in the absorption tower 1 is low, the large circulation pump must be stopped, and even in such a case, a smaller size than the circulation pump 32 is provided so that slurry can be supplied to the ejector 54. This is because the slurry can be supplied also from the extraction pump 42. For example, when liquid removal is performed at the time of inspection of the absorption tower 1, the slurry supply from the circulation pump 32 is switched to the slurry supply from the extraction pump 42 as the liquid level decreases. (In the illustrated absorption tower 1, the liquid level at which the circulation pump is stopped is 5 m, whereas the liquid level at which the extraction pump 42 is stopped is 1.4 m.)

  FIG. 5 shows an actual deposition state of solid matter in the central portion of the liquid storage tank 20 of the absorption tower 1. When only the horizontal stirrer 21 (see FIG. 1 and the like) is used when the ejector 54 and the pipe line system 50 including the ejector 54 are not attached, the phantom line in FIG. As shown in FIG. 1, a large deposit of solid X ′ was observed. However, when the pipe line system 50 including the ejector 54 is attached and used with the horizontal stirrer 21, the accumulation of the solid substance X is extremely small as shown by the solid lines in FIGS. 5 (a) and 5 (b). became. The amount of deposited solids was reduced by about 90% compared to the case where the ejector 54 was not provided. That is, in the illustrated example, when the ejector 54 or the like is used, an area in which the solid matter X hardly accumulates occurs near the center of the liquid storage tank 20, and the maximum height of the solid matter X is less than 1 m in the accumulated area. Diminished.

It is a longitudinal section showing the whole absorption tower 1 as an embodiment of the invention. It is II-II sectional drawing in FIG. FIG. 3 is a plan view (FIG. 3A) and a side view (FIG. 3B) showing details of the structure near the center of FIG. FIG. 5 is a detailed view showing an upstream end (outlet) 51 of the pipeline system 50 leading to the ejector 54. It is a figure which shows the deposition condition of the solid substance X in the center part of the liquid storage tank 20 at the time of using the ejector 54 grade | etc., The same (a) is a top view, The same (b) is a bb sectional drawing in the same (a). is there. It is the longitudinal cross-sectional view (FIG. 6 (a)) and top view (the same (b)) which show the conventional common flue gas desulfurization apparatus 1 '. It is a longitudinal cross-sectional view which shows the flue gas desulfurization apparatus 1 '' described in patent document 2.

Explanation of symbols

1 Absorption tower 10 Gas-liquid contact area 20 Liquid reservoir 21 Horizontal stirrer (stirring means)
24 Cone 30 Circulation piping 32 Circulation pump 34 Horizontal header (Horizontal portion with expanded piping diameter)
42 Extraction pump 50 Pipe system 51 Upstream end (outlet)
54 Ejector A Gypsum slurry X Solid

Claims (7)

In the absorption tower of the flue gas desulfurization apparatus of the type in which the gypsum slurry is stored in a liquid storage tank and circulated between the upper gas-liquid contact area using a pump,
A flue gas characterized in that a stirring means for swirling the gypsum slurry inside the liquid storage tank is provided near the outer periphery of the liquid storage tank, and a means for increasing the flow rate of the gypsum slurry near the center is provided near the center of the liquid storage tank. Absorption tower of desulfurization equipment.   A propeller-type horizontal stirrer is provided as the stirring means for swirling the gypsum slurry, and a part of the gypsum slurry is taken out from the outlet side of the pump as the means for increasing the flow rate of the gypsum slurry near the center. The absorption tower of the flue gas desulfurization apparatus according to claim 1, further comprising a pipe line system for ejecting from a plurality of ejectors.   3. A horizontal portion having an enlarged pipe diameter is provided on the outlet side of the pump, and an upstream end of the pipeline system for taking out a part of the gypsum slurry is connected to an upper portion of the horizontal portion. Absorption tower of exhaust flue gas desulfurization equipment.   4. The flue gas desulfurization according to claim 2, wherein the nozzle and the diffuser in the ejector are made of ceramic, or one whose inner surface is lined with wear-resistant rubber or resin is used. 5. Equipment absorption tower.   The absorption tower of the flue gas desulfurization apparatus according to any one of claims 1 to 4, wherein the bottom plate of the liquid storage tank is subjected to wear-resistant lining including the vicinity of the center thereof. The above-mentioned means for increasing the flow rate of the gypsum slurry near the center is arranged so as to generate a flow from the center of the liquid reservoir outward and obliquely downward,
6. A conical or frustoconical upward cone is formed at the center of the bottom of the liquid reservoir, and an abrasion-resistant lining is applied to the upper surface of the cone. Absorption tower of exhaust flue gas desulfurization equipment. The direction of the increase in the flow rate in the above means for increasing the flow rate of the gypsum slurry near the center is determined so as to include a speed component in the turning direction by the stirring means. Absorption tower of the described flue gas desulfurization apparatus.

Images