JPH07241429A - Gas-liquid contacting device - Google Patents

Abstract

PURPOSE:To improve the dispersion of a liquid absorbent jetted upwards from a discharge pipe to obtain proper gas-liquid contact by making a device have a structure in which the liquid absorbent is discharged through a restriction part and a diffuser pipe and making the length of the discharge pipe be specific times as large as the bore diameter of the discharge pipe. CONSTITUTION:A pressure drop is caused when a liquid absorbent 3 is passed through a restriction part 2 of a discharge pipe 1. By cavitation caused when the pressure of the liquid absorbent 3 drops to not more than its vapor pressure, the liquid absorbent 3 jetted upwards is dispersed and spreads out over a large area to improve the gas-liquid contact efficiency. Since the vapor caused by pressure drop across the restriction part 2 is dissipated when pressure is restored in the discharge pipe 1, the length of the discharge pipe 1 is made to be 0.5-3 times as large as the bore diameter of the discharge pipe 1, allowing the dispersion of the jetted liquid by cavitation to be stabilized. Further, by making a device have a structure in which the restriction part 2 leads to the discharge pipe 1 through the diffuser pipe 12, a void is not caused in the discharge pipe 1 to obtain stable and high gas-liquid contact efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid contactor such as a wet flue gas desulfurizer for cleaning harmful components in exhaust gas and collecting soluble components in gas with an absorbing liquid.

[0002]

2. Description of the Related Art Conventionally, as a gas-liquid contactor, various types such as a spray tower, a packed tower, a venturi scrubber, and a bubble tower have been developed and put into practical use. However, there are advantages and disadvantages in each performance and characteristic. Therefore, a high-performance gas-liquid contactor having all of these advantages has been desired.

The applicant is the first application for utility model registration in 1982.
No. 46860 (Japanese Utility Model Laid-Open No. 59-53828) and Japanese Utility Model Laid-Open No. 63-46733 propose a gas-liquid contactor which provides the above-mentioned improvements. Hereinafter, referring to FIG. 5 and FIG.
These gas-liquid contact devices will be described.

FIG. 5 illustrates a gas-liquid contact device according to Japanese Utility Model Application No. 57-146860. In this gas-liquid contactor, a gas inlet and an outlet are arranged in the tower body so that one side is the upper side of the tower and the other side is the lower side, and the absorbing liquid is discharged into the inside of the tower body in a liquid column shape almost upward. It is characterized by arranging a plurality of discharge pipes that make it possible to effectively change the gas-liquid contact efficiency by adjusting the liquid column height of the absorbing liquid that is discharged almost upward in a liquid column. This is a new gas-liquid contact device that can be used.

That is, in FIG. 5, 5 and 7 are gas inlets and outlets, 6 is a tower body, and a discharge pipe 1 for discharging the absorbing liquid 3 in a columnar shape in the tower body is directed substantially upward.
Are arranged in the header pipe 4. A plurality of header pipes 4 are usually arranged, but they do not necessarily have to be arranged on the same plane. The absorbing liquid discharged in a liquid column form from the discharge pipe 1 is pumped from the liquid reservoir 8 at the bottom of the tower body 6 to the pump 1
The liquid column height can be arbitrarily changed by adjusting the discharge liquid amount. The discharged absorbing liquid reaches the highest position of the liquid column, and then falls by the action of gravity, and enters the liquid reservoir 8 in the lower part of the tower body. The gas has one of the portions indicated by reference numerals 5 and 7 as an inlet and the other as an outlet.

FIG. 6 illustrates a gas-liquid contact device according to Japanese Patent Application No. 63-46733. Since FIG. 6 is the same as that shown in FIG. 3 except for a throttle portion provided in the middle of the discharge pipe described below, the same portions are denoted by the same reference numerals. Reference numeral 5 is a gas (exhaust gas) inlet provided in the upper part of the tower body 6, and the exhaust gas to be treated flows downward from the inlet 5 into the tower body 6 and out from the outlet 7. Inside the tower body 6, a narrowed portion 2 having a small cross-sectional area is provided in the middle of each of a plurality of discharge pipes 1 connected to a header pipe 4 for discharging the absorbing liquid upward. A lower portion of the tower body 6 forms a reservoir 8 for the absorbing liquid 3, and a pipe having an opening in the reservoir 8 and a pump 11 arranged therein is connected to the header pipe 4, and the pump 11 stores the absorbing liquid 3 therein. From the discharge pipe 1 to the header pipe 4, and is jetted almost upward from the discharge pipe 1. Further, the absorbent liquid reservoir 8 is provided with a gas inlet pipe 9 having an opening 9 ', and the gas 10 is stored through the opening 9'.
It is designed to be blown into. The absorbing liquid 3 flowing in the header pipe 4 passes through the throttle portion 2 and has a high liquid flow velocity, so that the pressure is reduced. By lowering the pressure of the absorbing liquid in the throttle portion 2 in this manner, the absorbing liquid is vaporized, and the absorbing liquid jetted upward from the discharge pipe 1 is well dispersed and spreads over a wide range.

[0007]

However, in the gas-liquid contact device shown in FIG. 5, the absorbing liquid ejected upward in the form of a liquid column reaches the highest level and spreads and has a small spreading area, In order to make sure that the inflowing gas and the discharged absorbent are in contact with each other, it is necessary to arrange a large number of discharge pipes in the header pipe. Further, when the flow rate of the absorbing liquid discharged from the discharge pipe is reduced, there is a drawback that the spread area of the discharged absorbing liquid also becomes small.

Further, in the gas-liquid contact device shown in FIG. 6, since the throttle portion and the discharge pipe are directly connected to each other, the vapor generated in the throttle portion causes a gap in the discharge pipe, so that the liquid having the diameter of the throttle portion is mainly formed. There was a problem that the part was ejected.

In the gas-liquid contact device of the above type, the present invention devises the shape of the discharge pipe to improve the dispersion of the absorbing liquid ejected upward from the discharge pipe, thereby achieving good gas-liquid contact. It is intended to provide a gas-liquid contact device that can be obtained.

[0010]

The first object of the present invention is to arrange a gas inlet and an outlet in the tower body so that one is at the top of the tower and the other is at the bottom thereof, and the absorbing liquid is placed inside the tower body. In a gas-liquid contact device in which a plurality of discharge pipes for discharging upward are arranged, it has a structure for discharging the absorbing liquid from the discharge pipe through a throttle portion and a diffuser pipe, and the length of the discharge pipe is A gas-liquid contactor characterized in that the diameter is 0.5 to 3 times the diameter, and the second is a tower body in which gas inlets and outlets are arranged so that one is at the top of the tower and the other is at the bottom. Then
In a gas-liquid contactor in which a plurality of discharge pipes for discharging the absorbing liquid upward are arranged inside the tower body, the gas absorbing liquid has a structure in which the absorbing liquid is discharged from the discharging pipe through a throttle portion and a diffuser pipe. It is a gas-liquid contactor characterized in that a spiral projection is provided on the inner wall surface of the tube.

[0011]

In the first aspect of the present invention, the absorbing liquid causes a pressure drop when passing through the throttle portion of the discharge pipe, and jets upward due to cavitation that occurs when the pressure drops below the vapor pressure of the absorbing liquid. The absorbing liquid is dispersed and spread over a wide area, and the gas-liquid contact efficiency is improved. Further, the vapor generated by the pressure drop in the throttle portion disappears when the pressure is recovered in the discharge pipe. Therefore, by making the length of the discharge pipe 0.5 to 3 times the diameter of the discharge pipe, the liquid ejected by the cavitation is ejected. Stabilize dispersion. Further, in the structure shown in FIG. 6 in which the throttle portion and the discharge pipe are directly connected to each other, the vapor generated in the throttle portion causes a gap in the discharge pipe, and the liquid spouts the central portion with the diameter of the throttle portion unchanged. However, stable liquid dispersion cannot be obtained, but the structure from the throttle to the discharge pipe through the diffuser pipe eliminates the formation of voids in the discharge pipe, resulting in stable high gas-liquid contact efficiency. To be

In the second aspect of the present invention, a pressure drop occurs when the absorbing liquid passes through the narrowed portion of the discharge pipe, and cavitation occurs when the pressure drops below the vapor pressure of the absorbing liquid.
The absorbing liquid ejected upward is dispersed and spread over a wide area, and the gas-liquid contact efficiency is improved. Furthermore, by providing a spiral protrusion on the inner wall surface of the discharge pipe, a swirl flow is generated in the discharge liquid, and the absorbing liquid ejected from the discharge pipe can be spread over a wide area and finely dispersed. it can.

[0013]

EXAMPLES Hereinafter, the effects of the gas-liquid contactor of the present invention will be clarified by giving specific examples of the present invention. (Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an enlarged sectional view of an absorption liquid discharge pipe, and FIG. 2 is an overall sectional view of a gas-liquid contact device. The first embodiment is the same as the conventional one shown in FIG. 6 except for the discharge pipe and the diffuser pipe provided in the middle of the throttle portion, which will be described below, and therefore the same portions are denoted by the same reference numerals. .

Reference numeral 5 denotes an exhaust gas inlet provided in the upper part of the tower main body 6, and the exhaust gas to be treated flows downward from the inlet 5 into the tower main body 6 and out from the outlet 7. In the middle of each of a plurality of discharge pipes 1 connected to a header pipe 4 that discharges the absorbing liquid upward into the tower body 6, a narrowed portion 2 having a small cross-sectional area and a diffuser pipe 1 are provided.
Two are provided. A lower portion of the tower body 6 forms a reservoir 8 for the absorbing liquid 3, and a pipe having an opening in the reservoir 8 and a pump 11 disposed therein is connected to the header pipe 4, and the pump 11 stores the absorbing liquid 3 therein. From the discharge pipe 1 to the header pipe 4, and is jetted almost upward from the discharge pipe 1. Further, a gas inlet pipe 9 having an opening 9'is provided in the absorbing liquid reservoir 8 so that the gas 10 is blown into the absorbing liquid reservoir 8 through the opening 9 '.

In the first embodiment, the header pipe 4
The absorbing liquid 3 flowing through the flow path passes through the throttle portion 2 and is decompressed due to the increase in the liquid flow velocity, and after passing through the throttle portion 2, the liquid flow velocity is reduced in the diffuser pipe 12 to recover the pressure. By lowering the pressure of the absorbing liquid in the throttle portion 2 in this manner, the absorbing liquid is vaporized, and the absorbing liquid jetted upward from the discharge pipe 1 through the diffuser pipe 12 is well dispersed and spreads over a wide range. . Further, the absorbing liquid 3 generally contains bubbles, but in the first embodiment, a larger amount of bubbles are contained by blowing the gas 10 through the gas inlet pipe 9, and the absorbing liquid of the throttle portion 2 is thus included. The pressure drop causes the bubbles to expand rapidly and the absorbing liquid to spread over a wide area.

Further, in the discharge pipe 1, since the pressure is recovered, the generated bubbles partially disappear, so that the liquid dispersion is lowered. However, the length of the discharge pipe 1 should be 0.5 of the discharge pipe diameter.
From 3 to 3 times, stable liquid dispersion can be obtained.
Further, the liquid column ejected from the discharge pipe 1 is dispersed and the biased flow of gas and liquid is prevented, and uniform gas and liquid contact can be performed in the tower. In this embodiment, if the cross-sectional area of the throttle portion 2 can be adjusted, the fluid pressure in the throttle portion 2 can be adjusted.

(Experimental Example) As a comparative example of this Example 1,
By using the gas-liquid contact device shown in FIG.₂: 700
Exhaust gas containing ppm 14,000m³/ H is the gas absorption liquid
As CaCO ₃Gas-liquid contact was made using a slurry. The above
In the gas-liquid contact device shown in FIG. 6, four discharge pipes 1 are provided.
The inner diameter is 50 mm, the inner diameter of the narrowed portion 2 is 40 mm,
The diffuser tube 12 is not provided.

As the gas absorbing liquid, CaCO ₃ : 20w
t%, using the slurry of water as the balance, the gas absorbing liquid was sent to the header pipe 4 of the gas-liquid contactor at 280 m ³ / h, and no air was sent to the gas inlet pipe 9. It was When the exhaust gas was introduced downward from above the liquid column top of the gas absorbing liquid while ejecting the gas absorbing liquid upward from the four discharge pipes 1, the exhaust gas SO ₂ concentration was 1
It became 05 ppm.

Next, in the first embodiment, the diffuser pipe 12 shown in FIG.
The discharge pipe length was set to 40 mm, with a structure in which the spread angle was set to 5 degrees between the and the narrowed portion 2. Exhaust gas outlet SO ₂
Was 56 ppm, and it was confirmed that the gas-liquid contact efficiency was higher than that in the first example.

Further, the discharge pipe length is 20 mm, 40 m
Experiments were conducted under five conditions of m, 150 mm, 200 mm and 300 mm, and the results shown in Table 1 were obtained. That is, at a discharge pipe length that is less than 3 times the discharge pipe diameter,
It was confirmed that the SO ₂ concentration at the outlet was lowered and the gas-liquid contact efficiency was increased. However, it is 0.4 times the diameter of the discharge pipe.
When the discharge pipe length was 0 mm, the SO ₂ concentration at the outlet was high and the gas-liquid contact efficiency was low.

[0021]

[Table 1]

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is an enlarged sectional view of the absorbent discharge pipe, and FIG. 4 is an overall sectional view of the gas-liquid contact device. The second embodiment is also the same as the conventional one shown in FIG. 6 except for the discharge pipe and the diffuser pipe provided in the middle of the throttle portion, which will be described below, and therefore the same portions are denoted by the same reference numerals.

Reference numeral 5 denotes an exhaust gas inlet provided in the upper part of the tower main body 6, and the exhaust gas to be treated flows downward from the inlet 5 into the inside of the tower main body 6 and flows out from the outlet 7. In the middle of each of a plurality of discharge pipes 1 connected to a header pipe 4 that discharges the absorbing liquid upward into the tower body 6, a narrowed portion 2 having a small cross-sectional area and a diffuser pipe 1 are provided.
Two are provided. Inside the discharge pipe 1, a spiral projection 13 is provided. The lower part of the tower body 6 is the absorbing liquid 3
A reservoir 8 is formed, and a pipe having an opening in the reservoir 8 and a pump 11 arranged therein is connected to the header pipe 4,
The pump 11 sends the absorbing liquid 3 from the reservoir 8 to the header pipe 4, and jets the absorbing liquid 3 substantially upward from the discharge pipe 1. In addition, an opening 9'is formed in the absorbent reservoir 8.
The gas inlet pipe 9 having the above is provided, and the gas 10 is blown into the absorbing liquid reservoir 8 through the opening 9 '.

In the second embodiment, the header pipe 4 is used.
The absorbing liquid 3 flowing through the flow path passes through the throttle portion 2 and is decompressed due to the increase in the liquid flow velocity, and after passing through the throttle portion 2, the liquid flow velocity is reduced in the diffuser pipe 12 to recover the pressure. By thus reducing the pressure of the absorbing liquid in the throttle portion 2, the absorbing liquid is vaporized and jetted upward from the discharge pipe 1 through the diffuser pipe 12 while swirling by the spiral projection 13. Further, the absorbing liquid 3 generally contains bubbles, but in the second embodiment, the gas 1 is supplied from the gas inlet pipe 9.
By injecting 0, a larger amount of bubbles are contained, and the bubbles rapidly expand due to the pressure drop of the absorbing liquid in the throttle portion 2, and the absorbing liquid spreads over a wide area.

(Experimental Example) As a comparative example of this Example 2, using the gas-liquid contactor shown in FIG. 6, SO ₂ : 700 p
Exhaust gas of 14,000 m ³ / h containing pm was brought into gas-liquid contact with CaCO ₃ slurry as a gas absorbing liquid. The gas-liquid contactor shown in FIG. 6 has four discharge pipes 1, the inner diameter of which is 50 mm, the throttle portion 2 has an inner diameter of 40 mm, and the diffuser pipe 12 is not provided.

As the gas absorbing liquid, CaCO ₃ : 20w
t%, using the slurry of water as the balance, the gas absorbing liquid was sent to the header pipe 4 of the gas-liquid contactor at 280 m ³ / h, and no air was sent to the gas inlet pipe 9. It was When the exhaust gas was introduced downward from above the liquid column top of the gas absorbing liquid while ejecting the gas absorbing liquid upward from the four discharge pipes 1, the exhaust gas SO ₂ concentration was 1
It became 05 ppm.

Next, in the second embodiment, the diffuser pipe 12 shown in FIG.
A divergence angle of 5 degrees is provided between the squeezing portion 2 and the narrowed portion 2, and a protrusion having a groove width of 2 mm is spirally formed at an angle of 45 ° in the vertical direction on the inner wall surface of the discharge pipe 1.

When the gas absorbing liquid was sent at 280 m ³ / h, it was confirmed that the exhaust gas SO ₂ concentration was 60 ppm and the gas-liquid contact efficiency was higher than that of the comparative example. Further, as a comparative example of this Example 2, the experiment was conducted under the same conditions except for the protrusions in the discharge pipe 1, and the exhaust gas SO ₂ concentration was 85 ppm. From this, it was confirmed that the gas-liquid contact efficiency was increased by the spiral protrusion.

[0029]

EFFECTS OF THE INVENTION According to the first and second aspects of the present invention, the dispersion of the ejected liquid column becomes good, and high gas-liquid contact efficiency can be obtained.
Further, it is possible to prevent a biased flow of gas-liquid and to make uniform contact of gas-liquid inside the tower body.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a gas absorbing liquid discharge pipe according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the gas-liquid contactor according to the first embodiment of the present invention.

FIG. 3 is a vertical sectional view of a gas absorbing liquid discharge pipe according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of a gas-liquid contactor according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of one aspect of a conventional gas-liquid contact device.

FIG. 6 is a vertical cross-sectional view of another aspect of the conventional gas-liquid contact device.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B01D 53/77 B01J 10/00 Z 8822-4G

Claims (2)

[Claims] 1. A plurality of discharge pipes for arranging a gas inlet and a gas outlet in the tower body such that one is an upper part of the tower and the other is a lower part, and discharges an absorbing liquid upward in the tower body. In the arranged gas-liquid contact device, it has a structure for discharging the absorbing liquid from the discharge pipe through the throttle portion and the diffuser pipe,
A gas-liquid contactor characterized in that the length of the discharge pipe is 0.5 to 3 times the diameter of the discharge pipe. 2. A plurality of discharge pipes for arranging a gas inlet and a gas outlet in the tower body such that one is an upper part of the tower and the other is a lower part, and discharges an absorbing liquid upward in the tower body. In the arranged gas-liquid contact device, it has a structure for discharging the absorbing liquid from the discharge pipe through the throttle portion and the diffuser pipe,
A gas-liquid contact device characterized in that a spiral projection is provided on the inner wall surface of the discharge pipe.