JP2001017829A - Double-chamber wet type flue gas desulfurization apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet type flue gas desulfurization apparatus whose installation cost and operation cost are lowered by simplifying the duct arrangement in the surrounding of an absorption tower and improving the desulfurization performance without increasing the pressure loss in the absorption tower. SOLUTION: An absorption tower of this desulfurization apparatus is provided with an absorption liquid storage circulation tank 7, a waste gas flow route from an inlet duct 2 to introduce a waste gas approximately horizontally into an upper side of an absorption liquid storage circulation tank 7 to a waste gas outlet duct 3 to discharge the waste gas approximately horizontally to the outside, a partitioning plate 4 partitioning the waste gas flow route into two regions; an upward current region 12 and a downward current region 13, and spray nozzles 16, 17 installed in the respective regions and in the absorption tower, SOx in a waste gas treated by bringing the waste gas into contact with an absorption liquid sprayed from the spraying nozzles 16, 17. The partitioning plate 4 is unevenly shifted to the waste gas downward flow region 13 side and the spray nozzles 16 are so arranged as to keep the spraying holes of the spraying nozzles 16 upward in the upward current region 12. By spraying the absorption liquid upward, even if the gas flow rate in the upward current region is increased to about 8 m/s from a conventional flow rate, 5 m/s, the increase of the pressure loss can be suppressed and the residence time of the droplets of the sprayed liquid can be elongated in the down current region 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet flue gas desulfurization apparatus and method for removing sulfur dioxide (SO2) in exhaust gas discharged from a combustion apparatus such as a boiler, and more particularly, to a partition plate inside an absorption tower. In the two-chamber desulfurization device divided into two gas-liquid contact parts of the upward flow region where the exhaust gas flows upward and the downward flow region where the exhaust gas flows downward, without increasing the pressure loss of the absorption tower, The present invention relates to a wet flue gas desulfurization apparatus or method capable of obtaining desulfurization performance.

[0002]

2. Description of the Related Art In thermal power plants and the like, sulfur oxides in flue gas generated by combustion of fossil fuels, especially SO
2 is one of the main causes of environmental problems such as air pollution and acid rain, and in recent years, the spread of flue gas desulfurization equipment on a global scale has been desired.

[0003] The current desulfurization system is dominated by the wet method based on the limestone-gypsum method.
Reliable spray type desulfurization equipment is widely used worldwide. This spray type desulfurization device has high desulfurization performance, and the basic technology is almost established.

[0004] However, the wet flue gas desulfurization equipment is expensive, and its penetration rate in developing countries is still low. Therefore, in order to increase the penetration rate of desulfurization equipment worldwide,
It is necessary to significantly reduce equipment costs and operation costs of the desulfurization unit. FIG. 8 shows a known example of a two-chamber wet flue gas desulfurization apparatus which adopts a conventional spray method and reduces cost.

This wet flue gas desulfurization apparatus mainly comprises an absorption tower main body 1, an inlet duct 2, an outlet duct 3, a partition plate 4, an absorption liquid circulation pumps 5 to 6, a circulation tank 7, a stirrer 8, an air blowing pipe 9 , Mist eliminator 10, absorption liquid discharge pipe 11,
Upflow area 12, Downflow area 13, Spray header 14
15, a counter-current spray nozzle 17 for injecting the absorbing liquid in a direction opposite to the gas flow, a co-current spray nozzle 16 for injecting the absorbing liquid in the gas flow direction, and the like.

A plurality of counter-current spray nozzles 17 and a plurality of parallel-flow spray nozzles 16 are provided in a cross section orthogonal to the gas flow, and are further provided in a plurality of stages in the gas flow direction. Further, the stirrer 8 and the air blowing pipe 9 are installed in the circulation tank 7 in which the absorbing liquid stays, and the mist eliminator 10 is installed in the outlet duct 3.

The exhaust gas discharged from the boiler (not shown) is introduced into the absorption tower body 1 from the inlet duct 2 in a substantially horizontal direction by a desulfurization fan (not shown), and is discharged from the outlet duct 3. Many of the spray tower absorption towers
The exhaust gas introduced from the lower part of the absorption tower is discharged from the top of the tower in order to bring the exhaust gas and the absorbing liquid into countercurrent contact. In the prior art shown in FIG. Is provided at substantially the same height as the inlet duct 2, the exhaust gas introduced from the inlet duct 2 is blocked by the partition plate 4, rises in the upflow region 12, reverses at the top of the tower, and then descends. 13 down.

In the meantime, in the ascending flow region 12 and the descending flow region 13, the absorption liquid containing calcium carbonate sent from the absorption liquid circulation pumps 5 and 6 is supplied to the counter-current spray nozzle 17 and the co-current spray nozzle provided in the respective regions. The gas is injected from the nozzle 16 and gas-liquid contact between the absorbing liquid and the exhaust gas is performed. At this time, the absorbing liquid selectively absorbs SO2 in the exhaust gas and generates calcium sulfite.

[0009] The absorption liquid which has produced calcium sulfite is temporarily stored in the circulation tank 7 and, while being stirred by the oxidizing stirrer 8, calcium sulfite is oxidized by oxygen in the air supplied from the air blowing pipe 9 and calcium sulfate (gypsum) ). A part of the absorbent in the circulation tank 7 where calcium carbonate and gypsum coexist is sent again to the counter-current spray nozzle 17 and the co-current spray nozzle 16 by the absorbent circulation pumps 5 and 6, and part of the absorbent is taken out of the absorbent discharge pipe 1.
1 to a waste liquid treatment / gypsum recovery system (not shown).

[0010] Of the absorbing liquid atomized by the injection from the counter-current spray nozzle 17 and the co-current spray nozzle 16, those having a small droplet diameter are accompanied by the exhaust gas.
The mist is collected by a mist eliminator 10 provided in the outlet duct 3.

In this prior art, since the outlet duct 3 is provided at a low height substantially at the same position as the inlet duct 2,
The supporting steel frame of the mist eliminator 10 and the outlet duct 3 (not shown) is low and simple, and the length of the duct for connecting to the heat exchanger (reheating side) not shown is also short.

However, in order to reduce the size of the absorption tower, if the size of a general single-chamber absorption tower having a gas flow rate of about 5 m / s is changed to a two-chamber absorption tower, the rising flow region 12 When the cross section of the downflow region 13 is the same, the gas flow velocity in each region is about 10 m /
s. In the descending flow region 13, there is no particular problem because the gas flow and the direction of drop of the droplet are the same, but in the upward flow region 12, gas flows against the drop of the droplet, and Since the gas flow velocity is almost the same as the velocity, the pressure loss increases sharply, and the power cost of the desulfurization fan (not shown) is greatly increased.

For this reason, as shown in FIG. 8, the partition plate 4 is eccentric to the descending flow region 13 to reduce the gas flow velocity in the ascending flow region 12 and increase the gas flow velocity in the descending flow region 13. Therefore, it is necessary to reduce the pressure loss of the entire absorption tower. However, even if the gas flow velocity in the descending flow region 13 is set to about 15 m / s, which is the same as the general flow velocity in the duct, the gas flow velocity in the ascending flow area 12 becomes about 8 m / s, which is 5 m in the prior art. 8 m / s is a high flow velocity compared to / m, and the pressure loss in the upflow region 12 must be high.

On the other hand, in the descending flow region 13, the pressure loss can be reduced, but when the gas flow rate is increased to about 15 m / s, the falling speed of the spray droplets is increased and the residence time of the droplets is shortened. In the flow region 13, it is difficult to obtain high desulfurization performance. Therefore, in order to improve the desulfurization performance in the downflow region, the amount of the absorbing liquid injected from the co-current spray nozzle 16 in the upflow region 12 must be increased.

[0015]

In the above prior art, sufficient consideration has not been given to reducing the pressure loss of the entire two-chamber absorption tower and improving the desulfurization performance in the exhaust gas downflow region, and the desulfurization fan and the absorption liquid circulation pump have not been considered. However, there is a problem that the operating cost becomes high with the increase in power of the motor.

An object of the present invention is to provide a wet flue gas desulfurization apparatus in which the arrangement of ducts around the absorption tower is simplified and the desulfurization performance is improved without increasing the pressure loss of the absorption tower, and the equipment and operation costs are low. And the way to get it.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for discharging exhaust gas discharged from a combustion device such as a boiler from an inlet duct in a substantially horizontal direction to an upper side of a circulation tank for storing an absorbent. By providing a partition plate having an opening on the ceiling side to divide the exhaust gas channel into two chambers on the inlet duct side and the outlet duct side. An upward flow area where the exhaust gas introduced from the duct flows upward, and a downward flow area where the exhaust gas flows downward toward the outlet duct after being inverted at the opening on the ceiling side, are injected from the spray nozzle installed in each area Contact the absorbing solution and exhaust gas
In a two-chamber type flue gas desulfurization device equipped with an absorption tower for treating sulfur oxides in exhaust gas, the partition plate is eccentric to the downward flow region side, and the spray holes of the spray nozzle are directed upward at least in the upward flow region. The problem is solved by a two-chamber type flue gas desulfurization device in which spray nozzles are arranged as follows.

An object of the present invention is to provide an exhaust gas passage for introducing exhaust gas discharged from a combustion device such as a boiler in a substantially horizontal direction and discharging the exhaust gas in a substantially horizontal direction above a circulation tank for storing an absorbing liquid. And an upward flow area in which the exhaust gas to be introduced flows upward, and an exhaust gas flow area divided into two chambers, a downward flow area in which the exhaust gas flows downward after being inverted at the opening on the ceiling side, and each area is formed. In the two-chamber wet-type flue gas desulfurization method equipped with an absorption tower for injecting the absorbent and contacting the exhaust gas and treating sulfur oxides in the exhaust gas, the capacity of the upflow area is made larger than the capacity of the downflow area. In addition, the above problem is also solved by a two-chamber type flue gas desulfurization method in which the absorbing liquid is injected at least in the upward flow region in a direction parallel to the exhaust gas flow.

In the two-chamber type flue gas desulfurization method of the present invention, the absorbent may be injected upward from the spray nozzle in any of the exhaust gas upward flow region and the exhaust gas downward flow region. The spray pressure of the absorbing liquid of the spray nozzle installed in the exhaust gas descending flow area may be made relatively lower than the spray pressure of the spray nozzle in the exhaust gas ascending flow area, and further installed in the exhaust gas descending flow area. The spray angle of the absorbing liquid of the spray nozzle may be relatively larger than the spray angle of the spray nozzle in the upflow region.

The present invention also includes a flue gas desulfurization apparatus to which the above two-chamber type flue gas desulfurization method is applied.

[0021]

Conventionally, in the exhaust gas ascending flow region in a two-chamber absorption tower, the most common countercurrent spray in which the absorbing liquid is jetted downward from a spray nozzle is used from the viewpoint of improving the desulfurization performance. If it can be changed to, the pressure loss can be greatly reduced.

At this time, there is a concern that the desulfurization performance may be reduced. According to recent experimental results, the desulfurization performance in the co-current spray region near the spray nozzle is certainly reduced, but the absorbent is once injected upward. It has been found that because of the falling, the residence time of the spray droplets is prolonged, and the desulfurization performance is generally equal or higher due to the effect. Therefore, even if the gas flow velocity in the exhaust gas ascending flow region is increased from the conventional 5 m / s to about 8 m / s, the upward spray can suppress a rapid increase in pressure loss in the exhaust gas ascending flow region and further improve the desulfurization performance. Improvement is possible.

On the other hand, in the exhaust gas downward flow region, the gas flow rate is 1
Since the speed is increased to about 5 m / s, conventionally, from the viewpoint of reducing the pressure loss, the absorbing liquid is jetted downward from the spray nozzle so as to form a co-current spray with the gas flow.

However, if the absorbing liquid is jetted in a co-current direction into the gas stream descending at a high speed, the drop velocity of the spray droplets becomes extremely fast, and the spray liquid drops fall in a gas-liquid contact portion in the exhaust gas descending area in a short time. . As described above, when the absorbing liquid is sprayed in the exhaust gas descending region in parallel with the gas flow, the pressure loss can be reduced, but the residence time of the spray droplets becomes short, and it becomes difficult to obtain high desulfurization performance.

Therefore, in order to prolong the residence time of the spray droplets in the exhaust gas downward flow region, it is necessary to once inject the absorbing liquid upward from the spray nozzle and drop it while drawing a parabola. In the case of injecting the absorbing liquid upward, the pressure loss is greatly increased because of the countercurrent spray in the vicinity of the spray nozzle, but by lowering the spray pressure of the spray nozzle or increasing the spray angle,
It is possible to minimize the increase in the pressure loss.

Further, as described above, if the spray nozzle in the upward exhaust gas flow region is disposed with the injection direction of the spray nozzle facing upward, the pressure loss is reduced, so that the increase in the pressure loss in the downward exhaust gas flow region can be covered, and the entire absorption tower can be covered. High desulfurization performance can be obtained without increasing pressure loss.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an absorption tower of a two-chamber wet-type flue gas desulfurization apparatus according to an embodiment of the present invention.
FIG. 2 is a plan view of the absorption tower in FIG. 1 as viewed from above, and FIG. 3 shows another embodiment of the absorption tower in FIG. The spray direction of both spray nozzles is directed upward. FIG. 4 is a comparison of the desulfurization rate between the prior art and the embodiment of the present invention. FIG. 5 is a comparison of pressure loss between the prior art and the embodiment of the present invention. FIG. 6 shows another embodiment of the absorption tower of FIG. 2, in which the spray nozzle installed in the exhaust gas downward flow region is a low-pressure spray nozzle. FIG. 7 shows another embodiment of the absorption tower of FIG. 2, in which the spray nozzle installed in the exhaust gas downward flow region is a wide-angle spray nozzle.

In FIGS. 1 to 7, devices or members having the same functions are denoted by the same reference numerals, and description thereof will be omitted. A low-pressure spray nozzle 18 is installed in the exhaust gas descending region 13, and a wide-angle spray nozzle 19 is installed in the exhaust gas descending region 13.

The embodiment shown in FIGS. 1 and 2 differs from the prior art in that a co-current spray nozzle 16 is provided in the exhaust gas upflow region 12 and arranged so as to jet the absorbing liquid upward.

As can be seen from FIG. 2, the embodiment shown in FIG. 1 employs a square structure as the basic structure of the absorption tower. In this example, the spray nozzle installed in the exhaust gas upflow region 12 is a co-current spray nozzle 16 and the direction of injection of the absorbing liquid is changed upward, so that the co-current spray is formed near the nozzle to greatly reduce the pressure loss. Can be.

When the absorbent is jetted upward in the exhaust gas upflow region 12, the desulfurization performance in the co-current spray near the spray nozzle decreases, but the absorbent rises once, reverses, and then falls. In addition, the residence time of the spray droplets becomes longer, and the desulfurization performance in the exhaust gas ascending flow region 12 is improved by the effect.

In the embodiment shown in FIG. 3, a co-current spray nozzle 16 is installed in the exhaust gas upflow region 12 and a counter-current spray nozzle 17 is installed in the exhaust gas downflow region 13 so that the absorbing liquid is jetted upward. This is different from the prior art in that it is arranged in

When the absorbing liquid is ejected upward from the counter-current spray nozzle 17 in the downward flow area 13, the spray liquid drops once rises, turns over and then falls, so that the liquid droplets are lower than when spraying downward. Residence time becomes very long. Accordingly, the desulfurization performance is improved, but the pressure loss is greatly increased in the vicinity of the spray nozzle 17 due to the countercurrent spray.

However, in the present embodiment, the spray nozzle 16 installed in the exhaust gas ascending flow region 12 is of a co-current type, and the injection direction of the absorbing liquid is changed upward, so that a co-current spray is formed in the vicinity of the spray nozzle 16, Pressure loss can be greatly reduced.

When the absorbent is injected upward in the exhaust gas upflow region 12, the desulfurization performance of the co-current spray near the spray nozzle 16 is reduced, but the descending flow region 13
In the same manner as described above, the absorption liquid rises once, reverses, and then falls, so that the residence time of the spray droplets is prolonged, and the effect of the effect makes the desulfurization performance generally equal or higher. FIG. 4 shows a comparison of the desulfurization rate between the prior art and the embodiment of the present invention shown in FIG.

Assuming that the desulfurization rate of the prior art at a liquid / gas ratio (L / G) of 14 L / m3N is 1, the desulfurization rate is relatively expressed in comparison with this value. It can be seen that the desulfurization performance in the embodiment (1) can obtain higher performance than that of the prior art.

Although the desulfurization performance in the vicinity of the co-current spray nozzle 16 in the exhaust gas upflow region 12 is reduced, the absorbent is once jetted upward in both the exhaust gas upflow region 12 and the exhaust gas downflow region 13, and the spray droplets are retained. Because of the longer time, the desulfurization performance of the entire absorption tower is higher than in the prior art. Therefore, since L / G for obtaining the same desulfurization performance can be relatively low, the absorption liquid circulation pump 5
And 6 power can be reduced.

FIG. 5 shows a comparison of pressure loss between the prior art and the embodiment of the present invention shown in FIG.
FIG. 3 shows the ratio of the pressure loss in the embodiment of the present invention shown in FIG. 3 when the pressure loss of the entire absorption tower in the prior art is set to 1, but the pressure loss of the present invention is lower in the entire absorption tower. I understand.

Since the vicinity of the spray nozzle 17 in the exhaust gas descending flow region 13 becomes countercurrent spray, the pressure loss in the exhaust gas descending flow region 13 increases, but the exhaust gas rising flow region 12
In the vicinity of the co-current spray nozzle 16, the co-current spray is formed, so that the pressure loss in the upflow region 12 is reduced conversely, and the pressure loss is slightly smaller in the embodiment of the present invention than in the prior art as a whole of the absorption tower. Lower. Therefore, the power of the desulfurization fan can be reduced.

FIG. 6 shows another embodiment of the absorption tower shown in FIG. 3, which is different from the embodiment shown in FIG. 3 in that the spray nozzle 17 in the exhaust gas descending flow region 13 is replaced with a low-pressure spray nozzle 18.

The pressure loss in the spray portion is affected by the relative velocity between the droplet and the gas, and the greater the relative velocity, the higher the pressure loss. Therefore, if the jetting pressure of the absorbing liquid is reduced and the jetting speed of the spray droplets is reduced, the relative speed with respect to the gas is reduced, so that the pressure loss in the downflow region 13 can be reduced.

FIG. 7 shows another embodiment of the absorption tower of FIG. 3, which is different from the embodiment of FIG. 3 in that the countercurrent spray nozzle 17 in the exhaust gas descending flow region 13 is replaced by a wide-angle spray nozzle 19. Increasing the injection angle of the absorbing liquid decreases the relative velocity between the spray droplets and the gas, so that the pressure loss in the downflow region can be reduced.

When the jetting angle of the absorbing liquid is increased, the absorbing liquid is apt to be atomized and the particle size of the spray droplets is reduced, so that the gas-liquid contact area is increased and the desulfurization performance is further improved. Become.

[0044]

As described above, according to the present invention, the residence time of spray droplets in the upflow region and the downflow region without increasing the pressure loss at the gas-liquid contact portion of the two-chamber absorption tower. And the desulfurization performance can be improved, the power of the absorbent circulation pump can be reduced, and the operating cost of the desulfurization device can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of an absorption tower of a two-chamber wet flue gas desulfurization apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the absorption tower in FIG. 1 as viewed from above.

FIG. 3 is a side view of the absorption tower of the two-chamber wet flue gas desulfurization apparatus according to the embodiment of the present invention, in which the spray nozzles in both the upflow region and the downflow region are directed upward.

FIG. 4 is a comparison of the desulfurization rate between the prior art and the embodiment of the present invention.

FIG. 5 is a comparison of the pressure loss between the prior art and the embodiment of the present invention.

FIG. 6 shows another embodiment of the absorption tower shown in FIG. 3, in which a spray nozzle installed in a downflow region is a low-pressure spray nozzle.

FIG. 7 shows another embodiment of the absorption tower shown in FIG. 3, in which a spray nozzle installed in a downflow region is a wide-angle spray nozzle.

FIG. 8 is an absorption tower in a conventional two-chamber wet flue gas desulfurization apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Absorption tower main body 2 Inlet duct 3 Outlet duct 4 Partition plate 5, 6 Absorbent liquid circulation pump 7 Circulation tank 8 Stirrer 9 Air injection pipe 10 Mist eliminator 11 Absorbent liquid extraction pipe 12 Exhaust gas rising flow area 13 Exhaust gas descending flow area 14, 15 spray header 16 co-current spray nozzle 17 counter-current spray nozzle 18 low-pressure spray nozzle 19 wide-angle spray nozzle

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Hirofumi Yoshikawa 3-36 Takara-cho, Kure-shi, Hiroshima Babcock-Hitachi Inside Kure Research Laboratories (72) Naoki Oda 6-9 Takara-cho Kure-shi, Hiroshima Babcock-Hitachi, Ltd. F-term in Kure Plant (reference) 4D002 AA02 BA02 BA16 CA01 CA13 CA20 DA05 DA16 EA03 FA03 4D020 AA06 BA02 BA09 BB03 CB27 CC08 CD01

Claims (9)

[Claims] Claims 1. Above a circulation tank for storing an absorbing liquid,
It has an exhaust gas passage that introduces exhaust gas discharged from a combustion device such as a boiler from the inlet duct in a substantially horizontal direction, and discharges the exhaust gas in a substantially horizontal direction from the outlet duct. By providing a partition plate having an opening on the ceiling side for dividing into two chambers, an upward flow region in which exhaust gas introduced from the inlet duct flows upward,
After the gas is inverted at the opening on the ceiling side, the exhaust gas flows downward toward the outlet duct and forms a downward flow area. In a two-chamber chamber type flue gas desulfurization device provided with an absorption tower for treating oxides, the partition plate is eccentric to the downward flow region side, and at least in the upward flow region, the spray nozzle is arranged so that the injection holes face upward. A two-chamber type flue gas desulfurization unit, which is arranged. 2. The two-chamber wet flue gas desulfurization according to claim 1, wherein the spray nozzles are arranged so that the spray holes of the spray nozzles face upward in both the upward flow region and the downward flow region. apparatus. 3. A two-chamber wet drain according to claim 1, wherein a hollow nozzle for injecting the absorbing liquid into a hollow cone is used as the spray nozzle installed in the downward flow region. Smoke desulfurization equipment. 4. The method according to claim 1, wherein the injection pressure of the absorbing liquid of the spray nozzle provided in the downward flow region is relatively lower than the injection pressure of the absorbing liquid of the spray nozzle in the upward flow region. A two-chamber wet flue gas desulfurization apparatus according to the above-mentioned. 5. The liquid jet apparatus according to claim 1, wherein the spraying angle of the absorbing liquid of the spray nozzle installed in the downflow area is relatively larger than the spraying angle of the absorbing liquid of the spray nozzle in the upflow area. A two-chamber wet flue gas desulfurization apparatus according to the above-mentioned. 6. Above a circulation tank for storing an absorbing liquid,
An upflow area in which exhaust gas discharged from a combustion device such as a boiler is introduced in a substantially horizontal direction, the exhaust gas flow path is discharged in a substantially horizontal direction, and the introduced exhaust gas flows upward, and an opening on a ceiling side. Form a divided exhaust gas flow area divided into two downward flow areas where the exhaust gas flows downward after reversing, and in each area, the absorbing liquid is injected to contact the exhaust gas and treat the sulfur oxides in the exhaust gas. In the two-chamber wet flue gas desulfurization method provided with an absorption tower, the capacity of the upflow area is made larger than the capacity of the downflow area, and at least in the upflow area, the absorbing liquid is injected in the co-current direction with the exhaust gas flow. Characteristic two-chamber type flue gas desulfurization method. 7. The two-chamber according to claim 6, wherein the ascending liquid is jetted in the upflow region in a direction parallel to the exhaust gas flow, and the ascending liquid is jetted in the downflow region in the countercurrent direction to the exhaust gas flow. Type wet flue gas desulfurization method. 8. The two-chamber wet drain according to claim 6, wherein the absorbent injection pressure in the downward flow region is relatively lower than the absorbent injection pressure in the upward flow region. Smoke desulfurization method. 9. The method according to claim 6, wherein the injection angle of the absorbing liquid in the downward flow area is relatively larger than the injection angle of the absorbing liquid in the upward flow area. Room type wet flue gas desulfurization method.