Title of Invention

“EXHAUST GAS DESULFURIZER”

Abstract

To provide a liquid-column type exhaust gas desulfurizer which realizes flexible response in which the increase of costs and work periods is suppressed to the minimum when the change of various conditions such as desulfurization performance, field control and the like are performed. In the liquid-column type exhaust gas desulfurizer performing desulfurization by allowing gas-liquid contact to generate between absorbing solution spouted from liquid column nozzles (20) and falling down inside a desulfurization tower and combustion exhaust gas rising from a lower part of the desulfurization tower, an outlet tip (30) which differs in a flow velocity or a spouting pattern of absorbing solution is installed at a tip portion of the liquid column nozzle (20) so as to be detachable.

Full Text

DESCRIPTION EXHAUST GAS DESULFURIZER Technical Field [0001] The invention relates to an exhaust gas desulfurizer applied to a coal-fired, a crude-oil fired or a heavy-oil fired power generating plant, and particularly relates to a liquid-column type exhaust gas desulfurizer which performs desulfurization by using absorbing solution (seawater, calcic water and the like). Background Art [0002] Conventionally, in the power generating plant using coal or crude oil as fuel, combustion exhaust gas exhausted from a boiler (hereinafter, referred to as "boiler exhaust gas") is discharged to the air after sulfur oxide (SOx) such as sulfur dioxide (SO2) and the like included in the boiler exhaust gas is removed therefrom. As a desulfurization method of the exhaust gas desulfurizer performing desulfurization processing, a liquid-column type exhaust gas desulfurizer is known, which performs desulfurization by gas-liquid contact between the absorbing solution such as seawater, calcic water or the like and the boiler exhaust gas inside a desulfurization tower. [0003] The liquid-column type exhaust gas desulfurizer is an apparatus in which a plurality of liquid column nozzles are installed inside the desulfurization tower and the absorbing solution is spouted up and falling to perform desulfurization by the gas-liquid contact between the falling absorbing solution and the boiler exhaust gas. In the conventional liquid column type, liquid column nozzles 1 which has an approximately cylindrical shape are used as shown, for example, in Fig. 17, Fig. 18A and Fig. 18B. A large number of liquid column nozzles 1 are provided to be directed upward on a header 2 installed in a horizontal direction in the desulfurization tower. The absorbing solution flown from the liquid column nozzle 1 will be stick shaped water column whose cross section is an approximately circle, which is spouted up to the liquid column height H which is prescribed according to characteristics set to the nozzles 1 as well as dispersed in circumferential directions to the dispersion width (diameter) W near the top of the column, then, falls down. The larger the dispersion width W in which the liquid column disperses is, the smaller liquid drops of the absorbing solution is dispersed into, and the area of the gas-liquid contact can be increased. [0004] Accordingly, in the liquid-column type exhaust gas desulfurizer, in addition to a flow rate of absorbing solution forming the liquid column, the liquid column height H which affects time of gas-liquid contact and dispersion property of absorbing solution which affects the liquid drop area of the gas-liquid contact (the diameter of the dispersion width W or the size of liquid drops) will be important on improving desulfurization efficiency. As another related art of the above exhaust gas desulfurizer, there is a technique in which a structure of arranging absorbent water spray apparatus above and below alternately is proposed with a view to improve the desulfurization efficiency. (For example, refer to Patent Document 1) Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2002-119827 Disclosure of Invention [0005] In the exhaust gas desulfurizer described above, as solution for improving a desulfurization rate in a condition that the flow rate of absorbing solution is fixed, it can be considered that the liquid column height H of the absorbing solution spouted from the liquid column nozzle is increased or the dispersion property thereof is increased. However, it is unable to change characteristics of the liquid column nozzle of the related art, therefore, it is difficult to respond to the change of various conditions flexibly. That is, it is necessary to change an absorbing solution supply unit such as a pump in order to increase the flow rate of absorbing solution, and the change which drastically increases costs, work periods and the like becomes necessary. However, when it is unable to change the flow rate of absorbing solution, measures such that the liquid column height H is increased by exchanging many liquid column nozzles are necessary, and costs and time are necessary also for exchanging liquid column nozzles. In addition, from the perspective that costs are reduced by downsizing the absorbent tower of the exhaust gas desulfurizer, it is desirable that the desulfurization performance is increased by increasing the dispersion property of absorbing solution spouted from the liquid column nozzles. [0006] From the above background, when the change of various conditions such as desulfurization performance, field control and the like are performed in the liquid-column type exhaust gas desulfurizer, it is desirable to enable the flexible response in which the increase of costs and work periods is suppressed to the minimum. The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid-column type exhaust gas desulfurizer which enables flexible response in which the increase of costs and work periods is suppressed to the minimum when the change of various conditions such as desulfurization performance, field control and the like are performed. Another object of the present invention is to improve the dispersion property of absorbing solution spouted from the liquid column nozzles in the liquid-column type exhaust gas desulfurizer. [0007] The invention applies the following solution in order to solve the above problems. An exhaust gas desulfurizer according to the invention is a liquid-column type exhaust gas desulfurizer performing desulfurization by gas-liquid contact between absorbing solution spouted from liquid column nozzles and falling down inside a desulfurization tower and combustion exhaust gas rising from a lower part of the desulfurization tower, in which an outlet tip which differs in a flow velocity or a spouting pattern of absorbing solution is installed at a tip portion of the liquid column nozzle so as to be detachable. [0008] According to the exhaust gas desulfurizer, the outlet tip which differs in the flowing velocity or the spouting pattern of absorbing solution is installed at the tip portion of the liquid column nozzle so as to be detachable, therefore, it is not necessary to change the whole liquid column nozzle, and the liquid column height and dispersion property of the liquid column nozzle can be changed only by exchanging the outlet tip. [0009] An exhaust gas desulfurizer according to the invention is a liquid-column type exhaust gas desulfurizer performing desulfurization by gas-liquid contact between absorbing solution spouted from liquid column nozzles and falling down inside a desulfurization tower and combustion exhaust gas rising from a lower part of the desulfurization tower, in which a liquid column dispersion mechanism is installed at a tip of the liquid column nozzle. [0010] According to the above exhaust gas desulfurizer, the liquid column dispersion mechanism is installed at the tip of the liquid column nozzle, which promotes the dispersion of the liquid column and increases liquid drops of absorbing solution, as a result, the surface area (gas-liquid contact area) of absorbing solution touching the combustion exhaust gas can be increased. The liquid column mechanism may be installed at an outlet tip of the liquid column nozzle. [0011] According to the present invention described above, the flow velocity or the spouting pattern of absorbing solution can be easily changed by exchanging the outlet chip installed at the tip portion of the liquid column nozzle so as to be detachable. Accordingly, it is not necessary to change the whole liquid column nozzle, and the liquid column height and the dispersion property of the liquid column nozzle can be changed only by exchanging the outlet tip. Therefore, when various conditions such as desulfurization performance are changed or when field control and the like are necessary, only the outlet tip have to be changed, therefore, flexible response can be realized, in which the increase of costs and work periods is suppressed to the minimum as compared with the case of changing the whole nozzle. In addition, it is possible to promote the dispersion of the liquid column and to increase the surface area of absorbing solution touching the combustion exhaust gas by installing the liquid column dispersion mechanism at the tip of the liquid column nozzle, therefore, the desulfurization tower can be downsized due to improvement of the desulfurization efficiency, which has great effect on the reduction of installation space or costs for the apparatus. Brief Description of Drawings [0012] [FIG. 1A] Fig. 1A is a plan view of an outlet shape in a first embodiment concerning a liquid column nozzle in a liquid-column type exhaust gas desulfurizer according to the present invention. [FIG. IB] Fig. IB is a cross-sectional view in the first embodiment concerning the liquid column nozzle in the liquid-column type exhaust gas desulfurizer according to the present invention, [FIG. 2A] Fig. 2A is a plan view of an outlet shape showing a first modification concerning the liquid column nozzle of Fig, 1A and Fig. IB. [FIG. 2B] Fig. 2B is a cross-sectional view showing the first modification concerning the liquid column nozzle of Fig. 1A and Fig. IB. [FIG. 2C] Fig. 2C is a front view showing the first modification concerning the liquid column nozzle of Fig. 1A and Fig. IB. [FIG. 3A] Fig. 3A is a plan view of an outlet shape showing a second modification concerning the liquid column nozzle of Fig. 1A and Fig. IB. [FIG. 3B] Fig. 3B is a cross-sectional view showing the second modification concerning the liquid column nozzle of Fig. 1A and Fig. IB. [FIG. 4A] Fig. 4A is a plan view of an outlet shape showing a third modification concerning the liquid column nozzle of Fig. 1A and Fig. IB. [FIG. 4B] Fig. 4B is a cross-sectional view showing the third modification concerning the liquid column nozzle of Fig. 1A and Fig. IB. [FIG. 5A] Fig. 5A is a plan view of an outlet shape showing a second embodiment concerning a liquid column nozzle including a liquid column dispersion mechanism of a radial outlet concerning a liquid-column type exhaust gas desulfurizer according to the invention. [FIG. 5B] Fig. 5B is a cross-sectional view showing a second embodiment concerning a liquid column nozzle including a liquid column dispersion mechanism of a radial outlet concerning a liquid-column type exhaust gas desulfurizer according to the invention. [FIG. 6A] Fig. 6A is a plan view of an outlet shape of a modification concerning the liquid column nozzle including the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 6B] Fig. 6B is a cross-sectional view of the modification example concerning the liquid column nozzle including the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 7A] Fig. 7A is a plan view showing an outlet shape of a liquid column nozzle including a liquid column dispersion mechanism of a concavocpnvex-shape portion of the first modification concerning the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 7B] Fig. 7B is a cross-sectional view of a first modification concerning the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 8A] Fig. 8A is a plan view of an outlet shape in the modification concerning the liquid column nozzle including the liquid column dispersion mechanism of the concavoconvex-shape portion shown in Fig. 7A and Fig. 7B. [FIG. 8B] Fig. 8B is a cross-sectional view of the modification concerning the liquid column nozzle including the liquid column dispersion mechanism of the concavoconvex-shape portion shown in Fig. 7A and Fig. 7B. [FIG. 9] Fig. 9 is a cross-sectional view of a liquid column nozzle including a liquid column dispersion mechanism of an ejector, which is a second modification concerning the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 10] Fig. 10 is a cross-sectional view showing a modification concerning the liquid column nozzle including the liquid column dispersion mechanism of the ejector shown in Fig. 9. [FIG. 11A] Fig. 11A is a plan view showing an outlet shape of a liquid column nozzle including a liquid column dispersion mechanism of a swirl flow forming device in a third modification concerning the liquid column dispersion mechanism of a radial outlet showh in Fig. 5A and Fig. 5B. [FIG. 11B] Fig. 11B is a cross-sectional view of the third modification concerning the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 12] Fig. 12 is a cross-sectional view showing a modification concerning a liquid column nozzle including the liquid column dispersion mechanism of the swirl flow forming device shown in Fig. 11. [FIG. 13A] Fig. 13A is a plan view showing an outlet shape of a liquid column nozzle including a liquid column dispersion mechanism of a gas suction port in a fourth modification concerning the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 13B] Fig. 13B is a cross-sectional view of the fourth modification concerning the liquid column dispersion mechanism of the radial outlet shown in Fig. 5A and Fig. 5B. [FIG. 14] Fig. 14 is a view explaining the effect concerning the liquid column height of liquid columns. [FIG. 15] Fig. 15 is a view explaining the effect concerning the dispersion width of liquid columns. [FIG. 16] Fig. 16 is a view showing the structural outline concerning a liquid-column type exhaust gas desulfurizer. [FIG. 17] Fig. 17 is a view showing the liquid column height and the dispersion width of conventional liquid column nozzles. [FIG. 18A] Fig. 18A is a plan view showing an outlet shape of a conventional liquid column nozzle in a liquid-column type exhaust gas desulfurizer. [FIG. 18B] Fig. 18B is a cross-sectional view showing the conventional liquid column nozzle in the liquid-column type exhaust gas desulfurizer. Explanation of Reference: [0013] 10: exhaust gas desulfurizer 11: desulfurization tower 13: header 20, 20A, B, C: liquid column nozzle 21, 21A, B, C: nozzle body 30, 30A, B, C: outlet tip (nozzle tip) 40: fixing belt 41: fixing bolt 50, 50', 50A: liquid column nozzle 51: nozzle body 60, 60': radial outlet (liquid column dispersion mechanism) 60A, 60B: concavo-convex shape portion (liquid column dispersion mechanism) 61, 61': notch 70, 70A: ejector (liquid column dispersion mechanism) 80: swirler (liquid column dispersion mechanism) 81: rifle groove (liquid column dispersion mechanism) 90: gas suction port (liquid column dispersion mechanism) Best Mode for Carrying Out the Invention [0014] Hereinafter, one embodiment of an exhaust gas desulfurizer according to the present invention is explained with reference to the drawings. In an exhaust gas desulfurizer 10 shown in Fig. 16, a desulfurization tower 11 is a liquid column type apparatus which removes sulfur oxide (SOx) such as sulfur dioxide (SO2) included in combustion exhaust gas (hereinafter, referred to as "boiler exhaust gas") exhausted from a boiler in the power generating plant using coal or crude oil as fuel by allowing gas-liquid contact to generate between absorbing solution such as seawater, calcic water or the like which is spouted in a columnar shape and the boiler exhaust gas before the boiler exhaust gas is discharged to the air. [0015] The exhaust gas desulfurizer 10 as shown in the drawing is configured to remove sulfur oxide, allowing gas-liquid contact to generate between an absorbing solution spouted from liquid column nozzles 20 and the boiler exhaust gas by supplying the absorbing solution and the boiler exhaust gas inside the tubular desulfurization tower 11 having a rectangular cross section which is vertically placed. The boiler exhaust gas supplied to the desulfurization tower 11 flows into the desulfurization tower 11 from an exhaust gas introducing port 12 provided at a lower portion of. the desulfurization tower 11 and rises. The absorbing solution supplied to the desulfurization tower 11 is spouted upward from a large number of liquid column nozzles 20 attached to headers 13 arranged in the desulfurization tower 11 and rises to the top of the liquid columns in the desulfurization tower 11, then, falls down naturally. [0016] Inside the desulfurization tower 11, plural headers 13 are arranged at predetermined intervals in the horizontal direction, and the respective headers 13 are connected to a not-shown supply pipe for the absorbing solution. A large number of liquid column nozzles 20 are attached above the respective headers 13 at an equal interval. The liquid column nozzles 20 form liquid columns having an approximately columnar shape by spouting the absorbing solution in the upward direction. The structure of the liquid column nozzle 20 will be specifically explained below. [0017] The liquid column nozzle 20 shown in Fig. 1A and Fig. IB is formed by including a nozzle body 21 and an outlet tip 30 attached to an upper end of the nozzle body 21 so as to be detachable. In the structural example shown in Fig.lA and Fig. IB, the nozzle body 21 and the outlet tip 30 are integrated so as to be detachable by screwing between outer threads 22 of the nozzle body 21 and inner threads 31 of the outlet tip 30 . Though not shown, necessary points are sealed by a gasket, an O-ring and so on. The nozzle body 21 is a member having an approximately ' cylindrical shape with a flange 23 for attaching the header, which will be the liquid column nozzle 20 having desired characteristics by attaching the outlet tip 30 which prescribes the nozzle characteristics at the upper end. [0018] The outlet tip 30 is a portion which prescribes the flow velocity, a pattern and the like of spouting absorbing solution, and plural types of tips having different outlet shapes or outlet sizes are prepared according to need. The outlet tip 30 shown in Fig. 1A has a circular cross—section, and the spouted absorbing solution forms a liquid column of an approximately columnar shape, therefore, it is possible to control the liquid column height by changing the outlet diameter of a flow path for the absorbing solution. According to the above structure, plural outlet tips 30 having different shapes in the outlet cross-section or different sizes in the outlet diameter of the flow path and the like though having the same sectional shape are provided, thereby the flow velocity or the spouting pattern of absorbing solution can be changed. Therefore, the liquid column nozzle 20 can easily change the flow velocity or the spouting pattern of absorbing solution by exchanging the outlet tip 30 attached at the tip portion so as to be detachable. [0019] A liquid column nozzle 20A of a first Modification shown in Fig. 2A, Fig. 2B and Fig. 2C is different in a structure in which a nozzle body 21A and an outlet tip 30A which is inserted to an upper end of the nozzle body 21A are integrated so as to be detachable. That is, the structure in which the outlet tip 30A is fixed to the nozzle body 21A by using a pair of fixing belts 40 is applied instead of the screwing structure in the above embodiment. Also in this case, necessary points are sealed by a not-shown gasket, an O-ring and so on. The fixing belt 40 shown in Fig. 2A, Fig. 2B and Fig. 2C is, for example, formed by bending a wire member having flexibility, and both end portions thereof are inserted into locking holes (not shown) in the nozzle body 21A, thereby overbear an upper surface of the outlet tip 30A to be fixed, which is in a state of being inserted from above and just being fitted. [0020] A liquid column nozzle 20B of a second modification shown in Fig. 3A and Fig. 3B has a structure in which an outlet tip 30B is inserted from an upper end of a nozzle body 21B and fixed by fixing bolts 41 from an outer periphery. In the shown example, three fixing bolts 41 are arranged at a pitch of 120 degrees, piercing the nozzle body 21B and reaching in the middle of the outlet tip 30B, thereby fixing the outlet tip 30B so as to prevent the movement in the axial direction. It Is preferable that the number of the fixing bolts 41 to be used is three or four, however, it is not particularly limited. [0021] A liquid column nozzle 20C of a third modification shown in Fig. 4A and Fig. 4B has a structure in which a flange portion 32 is formed at an outlet tip 30C and the outlet tip 30C is inserted from an upper end of a nozzle body 21C and fixed by fixing bolts 41 from above. In the shown example, three fixing bolts 41 are arranged at a pitch of 120 degrees, piercing the flange portion 32 and reaching the nozzle body 21C, which forms a fixing structure preventing the outlet tip 30C from moving in the axial direction. Also in this case, it is preferable that three or four fixing bolts 41 are used in general, however, it is not particularly limited. [0022] A liquid column nozzle 5 0 shown in Fig. 5A and Fig. 5B has a radial outlet 60 at a tip portion of the nozzle as a liquid column dispersion mechanism which promotes the dispersion of absorbing solution forming a liquid column. In the shown liquid column nozzle 50, the radial outlet 60 provided at the tip portion of a nozzle body 51 having an approximately cylindrical shape has an outlet shape to be a cross shape in which elongated rectangles cross each other in plan view. The absorbing solution spouted from the liquid column nozzle 50 is spouted from the cross-shaped outlet in which elongated rectangles cross each other, accordingly, the liquid column spouted in a stick shape is spread in circumferential directions due to the existence of a tilt portion 60a and the dispersion width W of the liquid column becomes large, as a result, the liquid column is easily dispersed into liquid drops by involving surrounding gas in the process of rising. When the absorbing solution falls down, it is in a state of being dispersed into relatively small liquid drops, therefore, the surface area of the absorbing solution contacting the boiler exhaust gas can be increased. [0023] In the state in which the surface area of absorbing solution (gas-liquid contact area) is increased by the dispersion of the absorbing solution as described above, efficient desulfurization by the absorbing solution becomes possible, therefore, the desulfurization performance in the whole apparatus will be improved by the increase of the gas-liquid contact area when the flow rate of the absorbing solution to be used is the same. In the structural example shown in Fig. 5B, the radial outlet 60 as the liquid column dispersion mechanism is integrated with the nozzle body 51 of the liquid column nozzle 50, however, it is also preferable to apply a structure in which the radial outlet 60 is detachable with respect to the nozzle body 51 by providing the radial outlet 60 as the liquid column dispersion mechanism at a separate outlet tip of the nozzle body 51 in the same manner as the above first embodiment. [0024] The radial outlet 60 of the above embodiment has the plan view of the cross shape, however, it is not limited to the cross shape and preferable to apply an outlet shape in which elongated rectangles are arranged in a radial pattern at a pitch of 45 degrees as a radial outlet 60' shown in, for example, Fig. 6A and Fig. 6B. [0025] Subsequently, a first modification of the above-described liquid column dispersion mechanism will be explained with reference to Fig. 7A and Fig. 7B. In the first modification, a concavoconvex-shape portion 60A is formed by rectangular notches 61 provided at the tip portion of the liquid column nozzle 50A at a prescribed pitch in a circumferential direction, and the concavoconvex-shape portion 60A functions as the liquid column dispersion mechanism. In this case, the surrounding boiler exhaust gas absorbed into the liquid column nozzle 50A from the notches 61 flows into the liquid column of the absorbing solution spouted from the liquid column nozzle 50A, therefore, the dispersion of the liquid column of the absorbing solution is promoted by the boiler-exhaust gas. The concavoconvex-shape portion 60A in this case is not limited to the rectangular shape, and various modifications can be applied such that a concavoconvex-shape portion 60B is formed by triangular notches 61' as shown in Fig. 8A and Fig. 8B. [0026] Subsequently, a second modification of the above liquid column dispersion mechanism will be explained with reference to Fig. 9 and Fig. 10. In the second modification, ejectors 70, 70A to be the liquid column dispersion mechanism are installed in the vicinity of the outlet of the liquid column nozzle 1 which applies the conventional structure. The liquid column positively absorbs the surrounding boiler exhaust gas when the liquid column passes and flows through the ejectors by providing such ejectors 70, 70A, therefore, the boiler exhaust gas promotes the dispersion of the liquid column. In the modification, the ejectors 70, 70A are combined with the liquid column nozzle 1 having the conventional structure, however, it is possible that the ejectors 70, 70A are combined with not only the liquid column nozzle 20 and modifications thereof shown in the first embodiment but also the liquid column nozzle 50 and modifications thereof having the liquid column dispersion mechanism shown Fig. 5A to Fig. 8B. [0027] Subsequently, a third modification of the above liquid column dispersion mechanism will be explained with reference to Fig. 11 A, Fig. 11B and Fig. 12. In the third modification, a swirl flow forming device to be the liquid column dispersion mechanism is provided at a suitable position of the liquid column nozzle 1. The swirl flow forming device shown in Fig. 11A and Fig. LIB is a swirler 80 provided in the vicinity of the outlet of the liquid column nozzle 1. The liquid column of absorbing solution spouted from the liquid column nozzle 1 will be the swirl flow by providing the swirler 80, therefore, the liquid column is spread in circumferential directions to increase the dispersion width W and absorbs the surrounding boiler exhaust gas into the liquid column in the process of rising while swirling. As a result, the boiler exhaust gas absorbed into the liquid column promotes the dispersion of the liquid column, being stirred by the swirl flow. [0028] As a swirl flow forming device which makes the liquid column spouted from the liquid column nozzle 1 be swirl flow, for example, there is a rifle groove 81 shown in Fig. 12, in addition to the above-described swirler 80. The rifle groove 81 is a helical groove formed in an inner peripheral face of the liquid column nozzle 1. Accordingly, the liquid column of absorbing solution spouted from the liquid column nozzle 1 in which the rifle groove 81 is provided flows out as the swirl flow by the rifle groove 81 when passing through the nozzle, therefore, the surrounding boiler exhaust gas is absorbed into the liquid column to promote the dispersion of the liquid column. The third modification is also not limited to the combination with respect to the liquid column nozzle 1 of the conventional structure, and it is possible to be combined with the liquid column nozzle 50 and modifications thereof having the liquid column dispersion mechanism shown in Fig. 5A to Fig. 10, in addition to the liquid column nozzle 20 and modifications thereof shown in the above first embodiment. [0029] Lastly, a fourth modification of the above liquid column dispersion mechanism will be explained with reference to Fig. 13A and Fig. 13B. In the fourth modification, gas suction ports 90 to be the liquid column dispersion mechanism are provided at suitable positions of the liquid column nozzle 1. In the shown structural example, eight gas suction ports 90 slanting upward are drilled in a radial pattern in the vicinity of the outlet of the liquid column nozzle 1. The surrounding boiler exhaust gas is absorbed into the absorbing solution flowing in the nozzle by providing such gas suction ports 90, therefore, the boiler exhaust gas absorbed into the liquid column promotes the dispersion of the liquid column. [0030] The drilling direction which is slanting upward and the number of drilling the above-described gas suction ports 90 are not limited to the structural example of the above Fig. 13A and Fig. 13B. The fourth modification is also not limited to the combination with respect to the liquid column nozzle 1 of the conventional structure, and it is possible to be combined with the liquid column nozzle 50 and modifications thereof having the liquid column dispersion mechanism shown in Fig. 5A to Fig. 12, in addition to the liquid column nozzle 20 and modifications thereof shown in the above first embodiment. [0031] According to the above-described invention, it is possible to easily change the flow velocity and the spouting pattern of absorbing solution by exchanging the outlet tip 30 attached at the tip portion of the liquid column nozzle 20 so as to be detachable. Therefore, it is not necessary to change the whole liquid column nozzle, and the liquid column height H and the dispersion property W of the liquid column nozzle 20 can be changed only by exchanging the outlet tip 30. Accordingly, the conventional liquid column height H can be increased to Ha as shown in, for example, Fig. 14, by exchanging for a nozzle tip 30 whose outlet diameter is smaller even when the flow rate of absorbing solution is not changed. In addition, it is possible to increase the dispersion width Wn by exchanging for the liquid column nozzle 50 in which the columnar dispersion mechanism is installed as shown in, for example, Fig. 15 even when the flow rate of absorbing solution is not changed, though the liquid column height Hn becomes lower than the conventional one. [0032] As a result, when various conditions such as desulfurization performance are changed or when field control and the like are necessary, the control can be performed by exchanging only the outlet tip 30, therefore, a flexible response in which the increase of costs and work periods is suppressed to the minimum will be realized "as compared with the case in which the whole nozzle is changed. In addition, it is possible to promote the dispersion of the liquid column and increase the area of absorbing solution touching the combustion exhaust gas by installing the liquid column dispersion mechanism at the tip of the liquid column nozzle, therefore, the desulfurization tower can be downsized due to the improvement of desulfurization efficiency, which enables the reduction of installation space and costs for the apparatus. The present invention is not limited to the above embodiments and can be suitably modified within a scope not departing from the gist of the invention. WE CLAIM 1. An exhaust gas desulfurizer which is a liquid-column type exhaust gas desulfurizer performing desulfurization by gas-liquid contact between absorbing solution spouted from a liquid column nozzle and falling down inside a desulfurization tower and combustion exhaust gas rising from a lower part of the desulfurization tower, wherein an outlet tip which differs in a flow velocity or a spouting pattern of absorbing solution is installed at a tip portion of the liquid column nozzle so as to be detachable. 2. An exhaust gas desulfurizer which is a liquid-column type exhaust gas desulfurizer performing desulfurization by gas-liquid contact between absorbing solution spouted from a liquid column nozzle and falling down inside a desulfurization tower and combustion exhaust gas rising from a lower part of the desulfurization tower, wherein a liquid column dispersion mechanism is installed at a tip of the liquid column nozzle.

Documents:

8147-DELNP-2009-Abstract-(15-12-2009).pdf

8147-DELNP-2009-Claims-(15-12-2009).pdf

8147-delnp-2009-Claims-(21-08-2014).pdf

8147-delnp-2009-Correspondence Others-(21-08-2014).pdf

8147-DELNP-2009-Correspondence-Others-(08-06-2010).pdf

8147-DELNP-2009-Correspondence-Others-(15-12-2009)--.pdf

8147-DELNP-2009-Correspondence-Others-(15-12-2009).pdf

8147-delnp-2009-Correspondence-others-(23-04-2012).pdf

8147-DELNP-2009-Description (Complete)-(15-12-2009).pdf

8147-DELNP-2009-Drawings-(15-12-2009).pdf

8147-delnp-2009-Drawings-(21-08-2014).pdf

8147-DELNP-2009-Form-1-(15-12-2009).pdf

8147-DELNP-2009-Form-18-(15-12-2009).pdf

8147-DELNP-2009-Form-2-(15-12-2009).pdf

8147-DELNP-2009-Form-26-(15-12-2009).pdf

8147-DELNP-2009-Form-3-(08-06-2010).pdf

8147-DELNP-2009-Form-3-(15-12-2009).pdf

8147-delnp-2009-Form-3-(21-08-2014).pdf

8147-delnp-2009-Form-3-(23-04-2012).pdf

8147-DELNP-2009-Form-5-(15-12-2009).pdf

Claims.pdf

Correspondence.pdf

Drawings.pdf

FER_SER REPLY.pdf

FORM 2.pdf

Form-1.pdf

Form-3.doc

Form-5.doc

Other.pdf

Petition under Rule 137.pdf