JP5777651B2 - Flue gas desulfurization equipment - Google Patents

Description

  The present invention relates to a flue gas desulfurization apparatus applied to power plants such as coal-fired, crude oil-fired, and heavy oil-fired, and particularly, a liquid column type flue gas desulfurization that uses an absorbent (such as seawater or lime water) to desulfurize. Relates to the device.

Conventionally, in a power plant using coal, crude oil or the like as fuel, combustion exhaust gas (hereinafter referred to as “boiler exhaust gas”) discharged from the boiler is sulfur dioxide (SO ₂ ) or the like contained in the boiler exhaust gas. Sulfur oxide (SOx) is removed before being released to the atmosphere. As a desulfurization method of the flue gas desulfurization device that performs such desulfurization treatment, there is a liquid column type flue gas desulfurization device that performs desulfurization by making gas-liquid contact between absorption liquid such as seawater and lime water and boiler exhaust gas inside the desulfurization tower. Are known.

The liquid column type flue gas desulfurization apparatus is an apparatus that installs a large number of liquid column nozzles inside a desulfurization tower to spout the absorption liquid, and desulfurizes the falling absorption liquid and boiler exhaust gas by gas-liquid contact.
In the conventional liquid column system, for example, as shown in FIGS. 17 and 18, a liquid column nozzle 1 having a substantially cylindrical shape is used. A number of liquid column nozzles 1 are attached upward from a horizontal header 2 installed in the desulfurization tower. The absorbing liquid flowing out from the liquid column nozzle 1 becomes a rod-shaped water column having a substantially circular cross section, and is sprayed to a liquid column height H determined according to the characteristics set in the nozzle 1 and has a dispersion width (diameter) W around the top. It falls after being dispersed in the circumferential direction. Note that the larger the dispersion width W in which the liquid column is dispersed, the more the absorbing liquid is dispersed into fine droplets, thereby increasing the area of gas-liquid contact.

Therefore, in the liquid column type flue gas desulfurization apparatus, in addition to the absorption liquid flow rate forming the liquid column, the liquid column height H that affects the gas-liquid contact time and the liquid-liquid contact droplet area are affected. The dispersibility (the diameter of the dispersion width W and the size of the droplets) of the absorbing liquid is important in improving the desulfurization efficiency.
In addition, another conventional technology of the above-described flue gas desulfurization apparatus has proposed a configuration in which the absorption water spraying means are alternately arranged up and down for the purpose of improving the desulfurization effect. (For example, see Patent Document 1)

No. 2002-119827

By the way, in the above-described flue gas desulfurization apparatus, as means for improving the desulfurization rate under the condition that the flow rate of the absorbing liquid is constant, increasing the liquid column height H of the absorbing liquid ejected from the liquid column nozzle and dispersibility. It is possible to increase. However, since the conventional liquid column nozzle cannot change the characteristics, it has been difficult to flexibly cope with changes in various conditions.
That is, in order to increase the flow rate of the absorption liquid, it is necessary to change the absorption liquid supply equipment such as a pump, and a change that greatly increases the cost, the construction period, and the like is necessary. However, when the flow rate of the absorbing liquid cannot be changed, it is necessary to take measures such as increasing the liquid column height H by replacing a number of liquid column nozzles. is necessary.
Further, from the viewpoint of reducing the cost by reducing the size of the absorption tower of the flue gas desulfurization apparatus, it is desired to increase the dispersibility of the absorbing liquid ejected from the liquid column nozzle to increase the desulfurization performance.

Against this background, in liquid column type flue gas desulfurization equipment, when changing various conditions such as desulfurization performance or on-site adjustment, it is possible to respond flexibly with minimal increase in cost and construction period It is desirable to do.
The present invention has been made in view of the above circumstances, and the object of the present invention is to minimize the increase in cost and construction period when carrying out change of conditions such as desulfurization performance and on-site adjustment. It is an object of the present invention to provide a liquid column type flue gas desulfurization apparatus that can be flexibly adapted. Another object of the present invention is to improve the dispersibility of the absorbing liquid ejected from the liquid column nozzle in the liquid column type flue gas desulfurization apparatus.

In order to solve the above problems, the present invention employs the following means.
The flue gas desulfurization apparatus according to the present invention is a liquid column system that desulfurizes an absorption liquid sprayed and dropped from a liquid column nozzle inside the desulfurization tower and a combustion exhaust gas rising from below the desulfurization tower by gas-liquid contact. In the flue gas desulfurization apparatus, a liquid column dispersing mechanism is attached to the liquid column nozzle, and the liquid column dispersing mechanism has a rectangular shape arranged radially in a plan view to disperse the liquid column blown up in a rod shape from the liquid column nozzle . A radial outlet at the tip of the nozzle, an uneven shape portion provided at an equal pitch in the circumferential direction at the tip of the nozzle that sucks and disperses the combustion exhaust gas into the liquid column ejected from the liquid column nozzle, and ejects from the liquid column nozzle An ejector installed near the nozzle outlet that sucks and disperses the combustion exhaust gas into the liquid column, or the combustion exhaust gas is sucked into the absorption liquid flowing in the liquid column nozzle to disperse the liquid column. It is characterized in that either of the gas suction port through the nozzle side wall.

  According to such a flue gas desulfurization apparatus, the liquid column dispersion mechanism is attached to the tip of the liquid column nozzle, thereby promoting the dispersion of the liquid column and increasing the number of liquid droplets of the absorption liquid. The area can be increased. Note that the liquid column dispersion mechanism may be attached to the outlet tip of the liquid column nozzle.

According to the present invention described above, by attaching a liquid column dispersion mechanism to the tip of the liquid column nozzle, it is possible to promote the dispersion of the liquid column and increase the area of the absorbing liquid that comes into contact with the combustion exhaust gas. As a result, the desulfurization tower can be reduced in size by improving the desulfurization efficiency, and a great effect is achieved in reducing the installation space and cost of the apparatus.
Further, according to the structure of the reference example in which the outlet tip having a different absorption flow velocity or ejection pattern of the absorbing liquid is detachably attached to the tip of the liquid column nozzle, the outlet tip attached detachably to the tip of the liquid column nozzle By exchanging, it is possible to easily change the ejection flow rate and ejection pattern of the absorbing liquid. For this reason, it is not necessary to replace the entire liquid column nozzle, and the liquid column height and dispersibility of the liquid column nozzle can be changed only by replacing the outlet tip. Therefore, when changing various conditions such as desulfurization performance or when site adjustment is required, it is only necessary to replace the outlet tip, which increases costs and construction time compared to replacing the entire nozzle. A flexible response that is minimized is possible.

The figure which shows the reference example regarding a liquid column nozzle about the liquid column type flue gas desulfurization apparatus which concerns on this invention, (a) is a top view of outlet shape, (b) is sectional drawing. It is a figure which shows the 1st modification regarding the liquid column nozzle of FIG. 1, (a) is a top view of exit shape, (b) is sectional drawing, (c) is a front view. It is a figure which shows the 2nd modification regarding the liquid column nozzle of FIG. 1, (a) is a top view of exit shape, (b) is sectional drawing. It is a figure which shows the 3rd modification regarding the liquid column nozzle of FIG. 1, (a) is a top view of exit shape, (b) is sectional drawing. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a first embodiment of a liquid column type flue gas desulfurization apparatus according to the present invention relating to a liquid column nozzle having a radial outlet liquid column separation mechanism, wherein (a) is a plan view of the outlet shape; b) is a sectional view. It is a modification regarding the liquid column nozzle provided with the liquid column separation mechanism of the radial exit shown in FIG. 5, (a) is a top view of outlet shape, (b) is sectional drawing. It is a 1st modification regarding the liquid column separation mechanism of the radial exit shown in FIG. 5, (a) is a top view which shows the exit shape of the liquid column nozzle provided with the liquid column separation mechanism of an uneven | corrugated shaped part, (b) is It is sectional drawing. It is a modification regarding the liquid column nozzle provided with the liquid column separation mechanism of the uneven | corrugated shaped part shown in FIG. 7, (a) is a top view of outlet shape, (b) is sectional drawing. FIG. 6 is a cross-sectional view of a liquid column nozzle including a liquid column separation mechanism of an ejector, which is a second modification example regarding the liquid column separation mechanism of the radial outlet illustrated in FIG. 5. It is sectional drawing which shows the modification regarding the liquid column nozzle provided with the liquid column separation mechanism of the ejector shown in FIG. It is a reference example regarding the liquid column separation mechanism of the radial outlet shown in FIG. 5, (a) is a top view which shows the exit shape of the liquid column nozzle provided with the liquid column separation mechanism of a swirl flow formation means, (b) is a cross section FIG. It is sectional drawing which shows the modification regarding the liquid column nozzle provided with the liquid column separation mechanism (reference example) of the swirl | vortex flow formation means shown in FIG. It is a 3rd modification regarding the liquid column separation mechanism of the radial outlet shown in FIG. 5, (a) is a top view which shows the exit shape of the liquid column nozzle provided with the liquid column separation mechanism of a gas suction port, (b) is It is sectional drawing. It is a figure explaining the effect regarding the liquid column height of a liquid column. It is a figure explaining the effect regarding the dispersion width of a liquid column. It is a figure which shows the outline | summary of a structure about a liquid column system flue gas desulfurization apparatus. It is a figure which shows the liquid column height and dispersion width of the conventional liquid column nozzle. It is a figure which shows the conventional liquid column nozzle about a liquid column type flue gas desulfurization apparatus, (a) is a top view of exit shape, (b) is sectional drawing.

Hereinafter, an embodiment of a flue gas desulfurization apparatus according to the present invention will be described with reference to the drawings.
In the flue gas desulfurization apparatus 10 shown in FIG. 16, the desulfurization tower 11 is included in combustion exhaust gas (hereinafter referred to as “boiler exhaust gas”) discharged from a boiler of a power plant using, for example, coal or crude oil as fuel. This is a liquid column type device that removes sulfur oxides (SOx) such as sulfur dioxide (SO2) by bringing them into gas-liquid contact with absorbing liquid such as seawater and lime water ejected in a columnar shape before being released to the atmosphere. .

The illustrated flue gas desulfurization apparatus 10 supplies an absorbing liquid and boiler exhaust gas into a desulfurization tower 11 having, for example, a rectangular cross-section of a cylinder placed vertically, thereby absorbing the absorbing liquid and boiler exhaust gas ejected from the liquid column nozzle 20. The gas-liquid contact is generated between the two and the sulfur oxide is removed.
The boiler exhaust gas supplied to the desulfurization tower 11 flows into the desulfurization tower 11 from the exhaust gas inlet 12 provided at the lower part of the desulfurization tower 11 and rises. The absorption liquid supplied to the desulfurization tower 11 is ejected upward from a number of liquid column nozzles 20 attached to the header 13 disposed in the desulfurization tower 11 and rises to the top of the liquid column inside the desulfurization tower 11. Later it falls naturally.

  Inside the desulfurization tower 11, a plurality of headers 13 are arranged in a horizontal direction with a predetermined interval, and each header 13 is connected to an absorption liquid supply pipe (not shown). In addition, a large number of liquid column nozzles 20 are attached to the top of each header 13 at an equal pitch. The liquid column nozzle 20 ejects the absorbing liquid upward to form a substantially columnar liquid column. Hereinafter, the configuration of the liquid column nozzle 20 will be specifically described.

<Reference example>
The liquid column nozzle 20 shown in FIG. 1 includes a nozzle body 21 and an outlet tip 30 that is detachably attached to the upper end portion of the nozzle body 21. In the configuration example shown in FIG. 1, the nozzle body 21 and the outlet tip 30 are detachably integrated by screwing the outer screw 22 of the nozzle body 21 and the inner screw 31 of the outlet tip 30. In addition, although illustration is abbreviate | omitted, the seal | sticker by packing, an O-ring, etc. is given to the required part.
The nozzle body 21 is a substantially cylindrical member provided with a flange 23 for attaching a header, and the liquid column nozzle 20 having desired characteristics is obtained by attaching an outlet tip 30 that defines nozzle characteristics to the upper end portion.

The outlet tip 30 is a part that defines the jetting flow velocity of the absorbing liquid, the jetting pattern, and the like, and a plurality of types having different outlet shapes and outlet dimensions are prepared as necessary. The outlet tip 30 shown in FIG. 1 has a circular cross section, and the jetted absorption liquid forms a substantially columnar liquid column, so that the liquid column height can be adjusted by changing the diameter of the absorption liquid channel outlet. It becomes.
With such a configuration, by preparing a plurality of different outlet cross-sectional shapes of the outlet tip 30 or those having the same cross-sectional shape but different dimensions such as the channel outlet diameter, the ejection flow rate and ejection pattern of the absorbing liquid can be set. Can be changed. Therefore, the liquid column nozzle 20 can easily change the jetting flow velocity and the jetting pattern of the absorbing liquid by exchanging the removable outlet tip 30 attached to the tip.

The liquid column nozzle 20A of the first modification shown in FIG. 2 is different in the structure in which the nozzle body 21A and the outlet tip 30A inserted into the upper end portion of the nozzle body 21A are detachably integrated. That is, a structure in which the outlet tip 30A is fixed to the nozzle body 21A using a pair of solid bands 40 is employed instead of the screwing structure of the above-described embodiment. Also in this case, the necessary portions are sealed with packing, O-rings, etc. (not shown).
Note that the fixed band 40 shown in FIG. 2 is formed by bending an elastic wire, for example, and is inserted from above by inserting both end portions into locking holes (not shown) of the nozzle body 21A. The upper end surface of the outlet tip 30A that is just fitted can be pressed and fixed.

  The liquid column nozzle 20B of the second modification shown in FIG. 3 has a structure in which the outlet tip 30B is inserted from the upper end portion of the nozzle body 21B, and then fixed by the fixing bolt 41 from the outer peripheral portion. In the example shown in the figure, three fixing bolts 41 are arranged at a pitch of 120 degrees, and pass through the nozzle body 21B and reach the middle of the outlet tip 30B, thereby fixing it so as to prevent movement in the axial direction. Yes. The number of fixing bolts 41 used is not particularly limited, although three or four are generally preferred.

  Further, the liquid column nozzle 20C of the third modification shown in FIG. 4 is provided with a flange portion 32 on the outlet tip 30C. After the outlet tip 30C is inserted from the upper end portion of the nozzle body 21C, the fixing bolt 41 is used from above. It has a fixed structure. In the illustrated example, three fixing bolts 41 are arranged at a pitch of 120 degrees and pass through the flange portion 32 to reach the nozzle body 21C, thereby fixing the outlet tip 30C from moving in the axial direction. It has a structure. The fixing bolt 41 in this case is not particularly limited, although generally three or four are used.

<First Embodiment>
The liquid column nozzle 50 shown in FIG. 5 has a radial outlet 60 attached to the tip of the nozzle as a liquid column dispersion mechanism that promotes dispersion of the absorbing liquid that forms the liquid column. In the illustrated liquid column nozzle 50, the radial outlet 60 provided at the tip of the substantially cylindrical nozzle body 51 has an outlet shape that is a cross shape obtained by orthogonally crossing elongated rectangles in plan view. That is, the absorbing liquid ejected from the liquid column nozzle 50 is ejected from a cross-shaped outlet in which long and narrow rectangles are orthogonal to each other, so that the liquid column blown up in a rod shape spreads in the circumferential direction by having the inclined portion 60a. The dispersion width W of the liquid column is increased, and in the process of rising, the surrounding gas is involved and is easily dispersed into droplets. Therefore, when the absorbing liquid falls, it is in a state of being dispersed in relatively fine droplets, so that the surface area of the absorbing liquid that is in gas-liquid contact with the boiler exhaust gas can be increased.

Thus, in the state where the surface area of the gas-liquid contact is increased by the dispersion of the absorbing liquid, efficient desulfurization by the absorbing liquid becomes possible, so if the flow rate of the absorbing liquid used is the same, the surface area of the gas-liquid contact As a result, the desulfurization performance of the entire apparatus is improved.
In the configuration example shown in FIG. 5, the radial outlet 60 serving as the liquid column dispersion mechanism is integrated with the nozzle body 51 of the liquid column nozzle 50. It is good also as a structure which can be attached or detached by providing the radial exit 60 of a liquid column separation mechanism in the exit chip | tip of a body.

  By the way, although the radial outlet 60 of the above-described embodiment has a cross shape in plan view, for example, an outlet shape in which elongated rectangles are arranged radially at a pitch of 45 degrees, such as a radial outlet 60 'shown in FIG. It is not limited to a cross shape.

Subsequently, a first modification of the above-described liquid column separation mechanism will be described with reference to FIG. In the first modified example, an uneven portion 60A is formed by a rectangular notch 61 provided at a predetermined pitch in the circumferential direction at the tip of the liquid column nozzle 50A, and the uneven portion 60A functions as a liquid column separation mechanism. To do. In this case, since the surrounding boiler exhaust gas sucked into the liquid column nozzle body 50A from the notch 61 flows into the liquid column of the absorbing liquid ejected from the liquid column nozzle 50A, the liquid column of the absorbing liquid is caused by this boiler exhaust gas. Dispersion will be promoted.
Further, the uneven shape portion 60A in this case is not limited to a rectangular shape, and there are various modified examples such as forming the uneven shape portion 60B by a triangular notch 61 'as shown in FIG. Is possible.

Subsequently, a second modification of the above-described liquid column separation mechanism will be described with reference to FIGS. In this second modification, ejectors 70 and 70A serving as a liquid column separation mechanism are installed in the vicinity of the outlet of the liquid column nozzle 1 adopting the conventional structure. By providing such ejectors 70 and 70A, when the liquid column passes through the ejector and flows, the surrounding boiler exhaust gas is positively sucked, so that the boiler exhaust gas promotes the dispersion of the liquid column.
In this modified example, the ejector 70, 70A is combined with the liquid column nozzle 1 having a conventional structure, but the liquid column nozzle 20 and the modified example shown in the reference example described above are not limited to FIGS. It is possible to combine with the liquid column nozzle 50 having the liquid column separation mechanism shown in FIG.

Next, a third modified example (reference example) of the above-described liquid column separation mechanism will be described with reference to FIGS. In this third modification, swirl flow forming means serving as a liquid column separation mechanism is provided at an appropriate position of the liquid column nozzle 1.
The swirl flow forming means shown in FIG. 11 is a swirler 80 provided near the outlet of the liquid column nozzle 1. By providing this swirler 80, the liquid column of the absorbing liquid ejected from the liquid column nozzle 1 becomes a swirling flow. Therefore, the liquid column spreads in the circumferential direction to increase the dispersion width W, and in the process of rising while swirling, The boiler exhaust gas is sucked into the liquid column. As a result, the boiler exhaust gas sucked into the liquid column is subjected to swirling agitation to promote the dispersion of the liquid column.

In addition to the swirler 80 described above, for example, a rifle groove 81 shown in FIG. 12 is used as the swirl flow forming means for swirling the liquid column ejected from the liquid column nozzle 1. The rifle groove 81 is a spiral groove formed on the inner peripheral surface of the liquid column nozzle 1. Accordingly, the liquid column of the absorbing liquid ejected from the liquid column nozzle 1 provided with the rifle groove 81 flows as a swirl flow through the rifle groove 81 when passing through the nozzle, so that the surrounding boiler exhaust gas is liquid. The suction of the column promotes the dispersion of the liquid column.
The third modified example (reference example) is not limited to the combination with the liquid column nozzle 1 having the conventional structure, and the liquid column nozzle 20 and the modified example shown in the reference example described above are not limited thereto. Of course, it is also possible to combine with the liquid column nozzle 50 having the liquid column separation mechanism shown in FIGS.

Finally, a third modification of the above-described liquid column separation mechanism will be described with reference to FIG. In the third modification , a gas suction port 90 serving as a liquid column separation mechanism is provided at an appropriate position of the liquid column nozzle 1. In the illustrated configuration example, eight obliquely upward gas suction ports 90 are formed radially in the vicinity of the outlet of the liquid column nozzle 1.
By providing such a gas suction port 90, the surrounding boiler exhaust gas is sucked into the absorbing liquid flowing in the nozzle, and therefore the boiler exhaust gas sucked into the liquid column promotes the dispersion of the liquid column. .

By the way, the gas suction port 90 described above is not limited to the configuration example of FIG. 13 described above with respect to the obliquely upward perforation direction, the number of perforations, and the like.
Further, the third modified example is not limited to the combination with the liquid column nozzle 1 having the conventional structure, and the liquid column nozzle 20 and the modified example shown in the reference example described above, of course, It is also possible to combine with the liquid column nozzle 50 having the liquid column separation mechanism shown in FIGS.

As described above, according to the present invention and the reference example described above, by changing the outlet tip 30 that is detachably attached to the tip of the liquid column nozzle 20, it is possible to easily change the ejection flow rate and ejection pattern of the absorbing liquid. it can. For this reason, it is not necessary to replace the entire liquid column nozzle, and the liquid column height H and dispersibility W of the liquid column nozzle 20 can be changed only by replacing the outlet tip 30.
Therefore, even if the flow rate of the absorbing liquid is not changed, the conventional liquid column height H can be increased to Ha by replacing the nozzle tip 30 with a small outlet diameter, for example, as shown in FIG. Even if the flow rate of the absorbing liquid is not changed, the liquid column height Hn is lower than the conventional one by using the liquid column nozzle 50 to which the columnar separation mechanism is attached as shown in FIG. Wn can be increased.

As a result, when various conditions such as desulfurization performance are changed or when on-site adjustment or the like is necessary, it is only necessary to replace and adjust the outlet tip 30, so compared with the case where the entire nozzle is replaced. Flexible response with minimal increase in cost and construction period is possible.
In addition, by installing a liquid column dispersion mechanism at the tip of the liquid column nozzle, it is possible to increase the area of the absorbing liquid that comes into contact with the combustion exhaust gas by promoting the dispersion of the liquid column. The size can be reduced, and the installation space and cost of the apparatus can be reduced.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

DESCRIPTION OF SYMBOLS 10 Flue gas desulfurization apparatus 11 Desulfurization tower 13 Header 20,20A-C Liquid column nozzle 21,21A-C Nozzle main body 30,30A-C Outlet tip 40 Fixing band 41 Fixing bolt 50,50 ', 50A Liquid column nozzle 51 Nozzle main body 60,60 'Radial outlet (liquid column separation mechanism)
60A, 60B Uneven shape part (liquid column separation mechanism)
61, 61 'Notch 70, 70A Ejector (liquid column separation mechanism)
80 swirler (liquid column separation mechanism)
81 Rifle groove (liquid column separation mechanism)
90 Gas suction port (liquid column separation mechanism)

Claims (1)

In a liquid column type flue gas desulfurization apparatus that performs desulfurization by making gas-liquid contact between an absorbing liquid sprayed from a liquid column nozzle and falling inside the desulfurization tower and a combustion exhaust gas rising from below the desulfurization tower,
A liquid column dispersion mechanism is attached to the liquid column nozzle,
The liquid column dispersion mechanism is
The liquid column blown up from the liquid column nozzle is dispersed by sucking and dispersing the combustion exhaust gas into a radial outlet at a nozzle tip portion in which elongated rectangular shapes are radially arranged in a plan view and a liquid column ejected from the liquid column nozzle. An uneven portion provided at an equal pitch in the circumferential direction at the nozzle tip to be ejected, an ejector installed near the nozzle outlet for sucking and dispersing the combustion exhaust gas into the liquid column ejected from the liquid column nozzle, or the liquid column A flue gas desulfurization apparatus characterized by being one of gas suction ports penetrating a nozzle side wall for sucking the combustion exhaust gas into the absorbing liquid flowing in the nozzle and dispersing the liquid column.

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