JPS59210289A - Gas-liquid catalytic device for liquefied gas - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a gas-liquid contact device for liquefied gas, and particularly to a gas-liquid contact device for liquefied gas that incorporates a plurality of perforated plates of a swirling flow type having an overflow pipe through which liquid flows down. The present invention relates to a gas-liquid contact device suitable for a rectification column.

[Background of the invention]

Gas-liquid contact equipment using a perforated plate with an overflow pipe has low pressure loss, high rectification performance, and simple structure, so it is suitable for chemical industries such as distillation, rectification, and absorption. It is widely used as a variety of gas-liquid contact devices.

By the way, in order to fully utilize the capacity of a rectification column incorporating a perforated plate, it is necessary to optimize the flow state of gas and liquid on the perforated plate. Further, since the pressure loss of the rectification column has a large effect on the power consumption of the air compressor, it is desirable to minimize the pressure loss as much as possible.

One way to reduce pressure loss is to reduce the rate of rise of gas, but this is not a good idea due to the trade-off between throughput and column diameter. Furthermore, there is a limit to the reduction in pressure loss due to the following reasons. First, the lower limit of the operating range of a perforated plate is determined by weaving, in which the liquid falls directly from the pores of the perforated plate onto the perforated plate one level below. This is because in a rationally porous plate having an overflow pipe, weaving directly reduces the rectification performance, so preventing weaving is an important issue. The second is a partially foamed state in which the liquid foams only partially on the perforated plate;
Gas-liquid contact on the perforated plate is only partially carried out.
This is because, like weaving, it directly reduces rectification performance.

The weaving and partially foaming state is due to the rising gas flow rate and the height of the liquid accumulated on the perforated plate, and is referred to as the liquid depth in the present invention. ) is greatly influenced by

In the same device, once the physical properties of the liquid flowing on the perforated plate, the hole diameter of the perforated plate, the arrangement pitch, the plate thickness, etc. are determined,
Gas flow rate passing through the holes in the perforated plate (hereinafter referred to as hole flow rate).

) and the static liquid depth, it is well known that weaving and partially foaming conditions occur. Therefore, in order to avoid weaving and partial foaming, it is important to maintain the rising gas flow rate in the column above a certain value and to maintain the same static liquid depth over the entire surface of the comb and perforated plate.

In order to reduce the pressure loss in the rectification column, various experiments were conducted on the flow state of the perforated plate, and the following points were clarified.

1. When the aperture ratio (hole area/perforated plate effective area) and hole flow rate are constant, the greater the static liquid depth, the more likely weaving and partial foaming will occur.

2. When the aperture ratio and liquid depth are constant, if the hole flow velocity becomes lower than a certain value, weaving and partial foaming will occur.

FIGS. 1 to 3 are explanatory diagrams of the flow of liquid in a perforated plate of a swirling flow type according to the prior art, and the prior art will be explained below using FIGS. 1 to 3. The swirling flow system includes one-way flow, two-way flow, and four-way flow, depending on the number of channels for liquid flowing on the perforated plate, and here, the case of two-way flow will be explained.

In Figures 1 to 3, l is the outer wall of the rectification column, 2 is the inlet weir, 3 is the perforated plate, 4 is the hole, 5 is the outlet weir, 6 is the overflow pipe, and the liquid is transferred to the hole 4 of the perforated plate 3. Since it flows over the perforated plate 3 from the inlet weir 2 to the outlet weir 5 side along the circumferential direction while coming into gas-liquid contact with the rising gas on the perforated plate 3, it is subject to the influence of centrifugal force and flow resistance. , the static liquid depth on the perforated plate 3 shows a tendency to increase in the radial direction from the center of the rectification column, and the static liquid depth is the largest at the outermost periphery of the perforated plate 3 and the smallest at the innermost periphery. Become.

Figures 4 and 5 are diagrams showing the distribution of static liquid depth when conducting experiments in a water-air system. In this example, the static liquid depth is approximately 8111 at the innermost periphery + 25 u + at the outermost periphery. It can be seen that there is a large difference between the innermost and outermost peripheries due to the effects of centrifugal force and liquid flow resistance.

On the other hand, the total pressure loss in the perforated plate 3 is composed of the dry pressure loss when gas passes through the holes 4 of the perforated plate 3, the surface tension pressure loss due to the effect of the surface tension of the liquid, and the wet pressure loss due to the depth of the static liquid. given by the sum.

Here, if the hole flow rate is constant, the drying pressure loss and the surface tension pressure loss are constant. However, the static liquid depth related to weaving and partial foaming is small on the inner circumferential side and becomes large on the outer circumferential side, and the total pressure loss is also large. In other words, weaving and partial foaming are more likely to occur on the outer peripheral side where the static liquid depth is greater.

In order to prevent weaving and partial foaming, it is necessary to plan based on the outer periphery of the perforated plate 3, where the static liquid depth at the hole flow rate is large, and to determine the pressure balance on the perforated plate 3 in addition to this. be.

However, on the inner periphery side where the static liquid depth is small, weaving and partial foaming can be prevented with a smaller hole flow rate than on the outer periphery side, so the hole flow rate should be adjusted to prevent weaving and partial foaming on the outer periphery side where the static liquid depth is large. If this is determined, the hole flow velocity will be higher than necessary. The experimental results also show that when the flow velocity in the holes is gradually increased, the perforated plate 3
The gas-liquid contact was carried out while maintaining the pressure balance between the inner and outer circumferential parts, and in the end, the flow rate at the hole was higher than necessary, causing the weaving to squeak, resulting in complete foaming. For this reason, the pressure loss becomes large, and the rectification column is allowed to have a pressure loss higher than necessary.On the other hand, if the flow rate at the hole is made low, weaving and partial foaming will occur on the outer periphery, resulting in the rectification column. There were problems in that performance deteriorated and the operating range became limited.

[Purpose of the invention]

The present invention has been made in view of the above, and its purpose is to provide a gas-liquid contact device for liquefied gas having an overflow pipe that can reduce pressure loss and widen the operating range. It's about doing.

[St key points of invention]

The present invention has a structure in which at least one row of rectifying plates having a height at least equal to or higher than the static liquid depth is attached on a perforated plate between an overflow pipe inlet and an overflow pipe outlet along the flow direction of the liquid. be.

[Embodiments of the invention]

The present invention will be explained in detail below with reference to the embodiments shown in FIGS. 6, 7, 11, and 12, and FIGS. 8 to 10.

FIG. 6 is an explanatory diagram showing one embodiment of the gas-liquid contact device of the present invention, and FIG. 7 is a plan view of FIG. 6. In FIGS. 6 and 7, l is a rectification column, which has a swirling flow type perforated plate 3 having an overflow pipe 6 (see FIG. 1 @) and forming an inlet weir 2 and an outlet weir 5. It has multiple built-in. The inlet weir 2 seals the overflow pipe 6 and prevents rising gas from flowing into the overflow pipe 6.
L, the outlet weir 5 is for maintaining a constant liquid depth on the perforated plate 3. The perforated plate 3 is installed horizontally within the rectification column 1, and a rectifier plate 7 is installed on the perforated plate 3 along the flow direction of the liquid.

The difference in static liquid depth between the inner and outer circumferential sides of the perforated plate 3 is determined by the hole velocity,
Liquid volume, gas volume, physical property constants of the fluid, and configuration of the rectification column (
large, flow method) etc. For this reason, the height and mounting position of the current plate 7 are influenced by these factors, so the mounting position and the height of the current plate 7 on the perforated plate 3 are determined by these factors. It is decided that the depth of the static liquid on the perforated plate 3 is the same, taking into consideration the following factors. That is, as shown in FIG. 7, the straightening plate 7 is installed between the overflow pipe outlet and the overflow pipe inlet along the flow direction of the liquid in a line, and the height of the straightening plate 7 is set so that the height of the straightening plate 7 is at least the same as that of the static liquid. The height was greater than the depth.

According to the embodiment of the present invention described above, when the liquid flows on the perforated plate 3 while being in gas-liquid contact with the rising gas, the static liquid depth increases ( On the outer periphery of the perforated plate, the static liquid depth is smaller than before,
On the other hand, it becomes thicker on the inner circumferential side. Figures 8 and 9 are diagrams showing examples of this. From this, the distribution of static liquid depth in the radial direction from the center of the rectification column becomes uniform. , it can be seen that the static liquid depth is almost the same over the entire surface of the perforated plate 3. Therefore, the reason why weaving and partial foaming occur is that the perforated plate 3
If the conditions are almost the same over the entire upper surface, for example, if the flow rate at the hole is the same as in the prior art, weaving and partial foaming will occur.

FIG. 10 is a diagram for explaining the effect of the above-described embodiment, and shows the relationship between the hole flow velocity, the zero pressure loss foaming rate, and the rectification efficiency. The solid line shows the conventional case, and the broken line shows the case according to the embodiment of the present invention. As mentioned above, weaving and partial foaming cause deterioration of rectification performance, and this can be solved by increasing the hole flow rate. It is necessary to increase the hole flow velocity according to the Therefore, conventionally, it has been necessary to determine the hole flow velocity based on the outer peripheral side of the porous plate where the static liquid depth is large. In other words, in order to prevent weaving and partial foaming caused by local differences in the depth of the static liquid on the perforated plate 3, the flow velocity in the holes had to be made thicker than necessary. As a result, the pressure loss was becoming louder.

On the other hand, when the plant is operated at a reduced capacity, that is, when the flow velocity at the hole is low, weaving and partial foaming occur, resulting in a decrease in performance. On the other hand, according to the embodiment of the present invention, the static liquid depth on the perforated plate 3 has a uniform distribution over the entire surface, so that the standard static liquid depth can be lowered than in the conventional case. can be used without requiring large hole flow velocities,
Moreover, weaving and partial foaming can be prevented from occurring. Therefore, even during a reduction operation in which the hole flow velocity is low, the rectification performance does not deteriorate, and the operating range can be made wider than before. Further, since the entire surface is foamed at a low flow rate in the holes and there is no weaving, the pressure loss due to the perforated plate 3 in the fully foamed state can be reduced.

11 and 12 are explanatory diagrams showing other embodiments of the present invention, respectively (bl is a plan view of (a), FIG.
The same parts as in FIG. 7 are indicated by the same reference numerals.

In FIG. 11, the rectifying plate 7 is provided with a hole 8, and in FIG.
The structure is arranged intermittently so as to have . According to these embodiments, even if the static liquid depth is less than the height of the rectifying plate 7, the liquid can move from one region to another via the rectifying plate 7, so that depending on the operating conditions of the rectifying column 1 and other factors, This is effective when there is a difference in flow rate between the inner and outer circumferential sides, and a difference in static liquid depth between the inner and outer circumferential sides.

Although the case where the liquid flow method is two-way flow has been described so far, the present invention can also be applied to one-way flow and four-way flow, and the same effect can be obtained by providing a number sequence. may be used and have the same effect.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reduce pressure loss and widen the operating range.

[Brief explanation of the drawing]

1 to 3 are structural explanatory diagrams of a gas-liquid contact device according to the prior art, FIGS. 4 and 5 are diagrams showing the distribution of static liquid depth on a perforated plate in the case of the prior art, and FIG. The figure is an explanatory diagram showing one embodiment of the gas-liquid contact device for liquefied gas of the present invention, FIG. 7 is a plan view of FIG. 6, and FIGS. FIG. 10 is a diagram for explaining the present invention in detail, and FIGS. 11 and 12 are explanatory diagrams showing other embodiments of the present invention. 1... Rectification tower, 2... Inlet weir, 3...
... Perforated plate, 4 ... Hole, 5 ... Outlet weir, 6 ... Overflow pipe, 7 ... Current plate,
8...Kong, 9...Clearance Department Agent Patent Attorney Akira Takahashi Unemployment 1 figure tz figure 4u, /f? For Kawakata (mth) 6-year-old 10-year old “X#te heel Nono”

Claims (1)

[Claims] 1. It has an overflow pipe through which the liquid flows down, and includes a plurality of perforated plates of a swirl flow type in which the liquid flows while swirling in the circumferential direction of the plate, and the liquid descends and rises. In the device in which rectification is carried out by bringing gas into gas-liquid contact on the perforated plate, the perforated plate has a small distance between the overflow pipe inlet and the overflow pipe outlet on the perforated plate along the flow direction of the liquid. 1. A gas-liquid contact device for liquefied gas, characterized in that it has a structure in which at least one row of rectifier plates each having a height equal to or higher than the static liquid depth are attached. 2. Claim 1, wherein the rectifier plate is provided with holes.
A gas-liquid contact device for liquefied gas as described in 1. 3. The gas-liquid contact device for liquefied gas according to claim 1, wherein a plurality of said baffle plates are disposed intermittently along the flow direction of the liquid.