JPH0211834B2 - - Google Patents

Description

Detailed Description of the Invention A. Technical Field The present invention has a plurality of plates that face each other to form alternating passages between them. The present invention relates to a plate-type evaporator that evaporates liquid by supplying heating fluid to a passage.

B. Prior art This type of evaporator has conventionally been of the natural circulation type or the weir type, each of which has been put to practical use. However, considering the use of heat pumps and the like under recent energy conditions, none of these conventional devices are satisfactory. In other words, in the case of the natural circulation type, it is pointed out that the specific gravity of the solution increases as the process progresses, making it difficult to evaporate depending on the liquid depth, and in the case of the weir type, the falling liquid film is long. As a result, the height of the entire evaporator becomes very high, and an increase in pump power for liquid circulation is unavoidable. Therefore, the evaporator itself has the disadvantage that not only the cost of the evaporator itself is high, but also that a large amount of money is required for the piping, the frame, and the like.

C. Purpose of the Invention The present invention aims to provide a plate-type evaporator having a structure that can eliminate the conventional drawbacks as described above. That is, the main object of the present invention is to provide an economical plate-type evaporator that can exhibit desired performance with a small pump power.

D. Structure of the Invention In order to achieve the above object, the plate type evaporator of the present invention is provided with a steam outlet 2 at the upper part, a concentrated liquid outlet 3 at the lower part, and a heating fluid supply port 4 and a discharge outlet. Shell 1 with outlet 5; housed within shell 1 and with gaskets 13,1
Openings 15 1 to 1 in the upper part, both sides, and the lower part are placed between the palms of the palms through 4 ₁ to _{14 3} .
While communicating with the internal space C of Ciel 1 at 5 ₄ ,
A first passage B is closed to the heating fluid supply port 4 and the discharge port 5, and a second passage B is closed to the internal space C of the shell 1 and communicates the heating fluid supply port 4 and the discharge port 5. vertically extending multi-speed plates 9 with short heat transfer lengths forming alternating passages A; from openings 15 ₁ to 15 ₄ at the top and side of the first passage B toward the inside of the passage; Nozzles 16 arranged in multiple stages for spraying liquid to be evaporated
group; a vapor derivation space D defined inside the shell 1 and outside the plate 9; and a concentrate outlet 3
a liquid circulation pump 19 connected to a conduit 18 leading from the nozzle 16 to the nozzle 16;

E. Effect of the Invention The liquid injected into the first passage B from the nozzle 16 falls on the heat transfer surface of the plate 1 in the form of a thin film, and at this time, the liquid is heated by the heated fluid flowing in the adjacent second passage A. It takes away and evaporates. The generated evaporation flows from the lower opening ₁₅₄ through the evaporation outlet space D to the upper steam outlet 2.

The unevaporated liquid, that is, the concentrated liquid, is sent to the liquid circulation pump 19.
As a result, the concentrated liquid is circulated from the concentrate outlet 3 to the nozzle 16.

F. Effects of the Invention According to this invention, since a plate with a relatively short heat transfer length is used and the liquid is injected so as to form a thin film on the heat transfer surface, the circulating flow rate of the concentrated liquid is Therefore, the power of the circulation pump can be reduced. In addition to this, not requiring a large frame etc. also contributes to cost reduction. In this way, it is possible to provide an economical plate-type evaporator that can meet the demand for energy conservation.

Furthermore, since the plate-type evaporator of the present invention is configured to guide and discharge the generated steam from the bottom to the top in a generally U-shape through the steam outlet space, it is possible to effectively separate mist from the steam. can.

Furthermore, the liquid sprayed from the nozzle
Direct contact with already formed vapor accelerates evaporation compared to simply creating a falling film on the heat transfer surface. In addition, since the liquid is injected inward from the openings at the top and side, a sealing effect is achieved, preventing the generated steam from escaping out of the passage against the flow, and quickly filling the opening at the bottom. can lead to.

G. Embodiments Hereinafter, embodiments of the present invention shown in the drawings will be described.

First, referring to FIG. 1, the shell 1 has a cylindrical shape with an oval cross section extending in the horizontal direction, and is provided with a steam outlet 2 at the upper part and a concentrated liquid outlet 3 at the lower part. A heating fluid supply port 4 and a discharge port 5 are provided on the end face 6 of the shell 1. The other end of the shell 1 is open as indicated by reference numeral 7, and is closed by flanging an end plate 8.

Multiple plates 9 move Ciel 1 and moving frame 1
0 by tightening means such as bolts. As can be seen from FIG. 2, each plate 9 is approximately rectangular and has a short heat transfer length (preferably 4
m or less) and has a heat transfer surface and through holes 11 and 12 that allow the heating fluid to flow therethrough. The plate 9 extends vertically, and in the palm-to-palm state, all the through holes 11 and 12 are aligned respectively, the through hole 11 serving as the heating fluid supply port 4, and the through hole 12 serving as the heating fluid discharge port. Connects with 5.

When these plurality of plates 9 come into contact with each other via gaskets, alternate passages A and B are formed between the plates. More specifically, as can be clearly seen from FIG. The holes 11, 12 and thus also the supply inlet 4 as well as the outlet 5 of the heating fluid communicate. The passage B of the liquid to be evaporated is separated from the through holes 11, 12 by partially cut out gaskets 14 ₁ to 14 ₃ , while the cut out parts of the gaskets, i.e. the openings 15 at the top, sides and bottom. It communicates with the internal space of Ciel 1 through ₁ to 15 ₄ .

A header 17 in which a group of nozzles 16 for injecting the liquid to be evaporated into each passage B is provided in _each passage B.
₂ and 15 ₃ so that the nozzle 16 is placed between them.
In the illustrated example, the nozzle groups are provided in three stages, but two or four or more stages may be provided as necessary.
Pipe line 1 leading from concentrate outlet 3 to header 17
8 is connected to a liquid circulation pump 19. In the discharge side pipe section of the liquid circulation pump 19, there is a take-out pipe 20 for the concentrated liquid and a replenishment pipe 2 for the liquid to be evaporated.
1 is connected.

Inside the shell 1, in addition to the portion occupied by the plate 1, a steam derivation space D is defined, which functions for deriving the steam generated in the passage B and separating mist. In addition to being defined in a portion of the cylindrical shell 1 in the axial direction as shown in the figure, the steam outlet space can also be defined on both sides of the plate 1 in a cross section perpendicular to the axis (FIG. 2). 2
2 is a normal demister attached to the steam outlet 2.

Next, the operation of the plate type evaporator constructed as described above will be described.

The heating fluid supplied from the supply port 4 provided in the shell 1 is supplied to the through hole 1 as shown by the solid line in FIG.
1 into the new passageway A, flows out through the through hole 12 and reaches the outlet 5.

The vaporized liquid is injected from the nozzle 16 into the passage B and flows down in a thin film over the heat transfer surface of the plate 1 facing the passage B, as shown by the broken line in FIG.

At this time, steam is generated due to heating by the heating fluid flowing through the adjacent passage A. The unevaporated liquid, that is, the concentrated liquid, is transferred from the opening ₁₅₄ at the bottom of passage B to shell 1.
The liquid drops to the bottom of the tank and is circulated from the outlet 3 through the pipe 18 to the header 17 by the liquid circulation pump 20. The concentrated liquid is taken out from the take-out pipe 20 as appropriate, and a certain amount of new liquid to be vaporized is accordingly or independently taken out from the supply pipe 20.
1.

The evaporation generated in passage B is shown in Figures 1 and 3.
As shown by the chain line in the figure, the steam flows out from the opening ₁₅₄ at the bottom of the passage B to the steam derivation space D.
After that, it heads to the steam outlet 2. During this time, the steam follows a generally U-shaped path, with the lower opening 15 ₄
When changing direction from the steam outlet 2 to the upper steam outlet 2, the mist is separated from the steam and settles at the bottom of the shell 1, as shown by the broken line in FIG. If there is still mist mixed in the steam, remove the demister 2.
Captured at 2.

[Brief explanation of drawings]

The drawings show an embodiment of the plate-type evaporator of the present invention, in which Fig. 1 is a schematic longitudinal cross-sectional view, Fig. 2 is a cross-sectional view taken along the - line in Fig. 1, and Fig. 3 is a cross-sectional view of the plate. FIG. 3 is an exploded perspective view showing the polymerization procedure and distribution state. DESCRIPTION OF SYMBOLS 1... Shell, 2... Steam outlet, 3... Concentrated liquid outlet, 4... Heating fluid supply port, 5... Heating fluid outlet, 9... Plate, 11, 12... Through hole, 13 , 14 ₁ ~ 14 ₃ ...Gasket, 15 ₁
~15 ₄ ...Opening, 16...Nozzle, 18...Pipe line, 19...Liquid circulation pump, A...Passway for heated fluid, B...Passway for liquid to be vaporized.

Claims (1)

[Claims] 1. A shell that is equipped with a steam outlet in the upper part, a concentrated liquid outlet in the lower part, and a heating fluid supply inlet and an outlet; a first passage that communicates with the internal space of the shell through openings at the top, both sides, and the bottom, and is closed to the heating fluid supply and discharge ports, and to the internal space of the shell; a plurality of vertically extending plates with short heat transfer lengths that alternately form second passages that are closed and communicate with the supply and discharge ports of the heating fluid; an upper portion and a side of the first passage; a group of nozzles arranged in multiple stages for injecting the liquid to be evaporated inward from the opening of the shell; a vapor lead-out space defined inside the shell and outside the plate; and the concentrated liquid discharge space. a liquid circulation pump connected to a pipe line leading from the outlet to the nozzle group; and the steam generated in the first passage is transferred from the opening in the lower part of the first passage to the steam extraction space. A plate type evaporator, characterized in that the steam is taken out through the steam outlet.