The present application has been divided out of Indian Patent
application no. 8147/DELNP/2009.
Technical Field
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
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.
3
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.
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
4
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
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
5
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.
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
6
the dispersion property of absorbing solution spouted from the
liquid column nozzles in the liquid-column type exhaust gas
desulfurizer.
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.
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.
An exhaust gas desulfurizer according to the invention is a
7
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.
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.
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
8
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
[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. 1B] Fig. 1B 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. 1B.
9
[FIG. 2B] Fig. 2B is a cross-sectional view showing the first
modification concerning the liquid column nozzle of Fig. 1A and
Fig. 1B.
[FIG. 2C] Fig. 2C is a front view showing the first
modification concerning the liquid column nozzle of Fig. 1A and
Fig. 1B.
[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. 1B.
[FIG. 3B] Fig. 3B is a cross-sectional view showing the second
modification concerning the liquid column nozzle of Fig. 1A and
Fig. 1B.
[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. 1B.
[FIG. 4B] Fig. 4B is a cross-sectional view showing the third
modification concerning the liquid column nozzle of Fig. 1A and
Fig. 1B.
[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
10
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 concavoconvex-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
11
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 shown 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
12
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:
10: exhaust gas desulfurizer
11: desulfurization tower
13: header
13
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
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
14
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.
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.
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
15
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.

The liquid column nozzle 20 shown in Fig. 1A and Fig. 1B 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.1A and Fig. 1B, 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.
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
16
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.
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.
17
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.
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.
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
18
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.

A liquid column nozzle 50 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.
19
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.
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.
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
20
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.
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.
21
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.
Subsequently, a third modification of the above liquid column
dispersion mechanism will be explained with reference to Fig. 11A,
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. 11B
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.
As a swirl flow forming device which makes the liquid column
22
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.
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
23
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.
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.
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.
24
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.
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
25
and can be suitably modified within a scope not departing from the
gist of the invention.
26

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 a liquid column dispersion mechanism is installed at
a tip of the liquid column nozzle.
Dated this 19th day of August 2014