JPS6080082A - Plate type evaporator - Google Patents

Abstract

PURPOSE:To permit to develop a predetermind capacity with small pumping power by a method wherein plates, having comparatively short heat-transfer length, are utilized and liquid is injected so as to form a thin film on the heat- transfer surface. CONSTITUTION:First path B, closed to the supply port 4 and discharge port 5 of heated fluid, as well as the second path A, communicating the supply port 4 of the heated fluid with the discharging port 5, are provided alternately. Fluid, injected from a nozzle 16 into the first path B, flows down on the heat-transfer surface of the plate 9 in the shape of a thin film and deprives heat from the heated fluid flowing through the neighboring second path A and evaporates in this case. Vapor, produced therein, flows to the upper vapor discharging port 2 from the lower opening 15 through a vapor introducing space D. Liquid, not vaporised yet or condensed liquid, is circulated to the nozzle 16 from a condensed liquid discharging port 3 by a liquid circulating pump 19. The plate 9 is rectangular substantially and is equipped with the heat-transfer surface of short heat-transfer length.

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, and a liquid to be evaporated is fed to one passage, and a liquid to be evaporated is fed to the other. The present invention relates to a plate-type evaporator that evaporates liquid by supplying heating fluid to the passages of the plate.

BACKGROUND OF THE INVENTION 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, these conventional devices are not satisfactory (2). 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, it is necessary to have a long falling liquid film. As a result, the height of the entire evaporator becomes extremely high, and an increase in pump power for liquid circulation is unavoidable. Therefore, it also has the disadvantage that not only the cost of the evaporator itself is high, but also a large amount of cost is required for piping, a frame, etc.

OBJECT OF THE INVENTION The present invention aims to provide a plate-type evaporator having a structure that can overcome the above-mentioned drawbacks of the prior art. 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.

20 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) in the upper part and a concentrated liquid outlet (3) in the lower part, and , heating fluid supply port (4) and discharge port (5)
); housed within the shell (1) and having openings (151 to 151) in the upper part, both sides and the lower part; a first passage (B) that communicates with the internal space (C) of the shell (1) at 154) and is closed to the heating fluid supply port (4) and the discharge port (5);
Vertically extending passages that close the internal space (C) of the shell (1) and alternately form second passages (A) communicating with the heating fluid supply port (4) and the discharge port (5). (9) i Inject the liquid to be evaporated inward from the openings (14, to 143) at the top and side of the first passage (B). a group of nozzles (16) arranged in multiple stages for
D); and from the concentrate outlet (3) to the nozzle (16)
A liquid circulation pump (19) connected to a pipe (18) leading to
includes i.

(4) The liquid injected from the nozzle (16) into the first passage (B) flows down on the heat transfer surface of the plate (1) in the form of a thin film. It evaporates by taking heat from the heating fluid flowing in the passage (A). The generated steam is released through the downward opening (15 to)
From the upper steam outlet (2) through the steam derivation space (D)
Head to.

The unevaporated liquid, that is, the concentrated liquid, is circulated from the concentrated liquid outlet (3) to the nozzle (1B) by the liquid circulation pump (19).

Effects of the Invention According to this invention, a plate with a relatively short heat transfer length is used, and the liquid is injected to form a thin film on the heat transfer surface, so that the circulation of the concentrated liquid is improved. The flow rate is small, and therefore the power of the circulation pump can be saved. 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 (5) 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 direct contact of the liquid injected from the nozzle with the already generated vapor accelerates evaporation compared to simply creating a falling liquid film on the heat transfer surface. Furthermore, since the liquid is injected from the top and side openings toward the inside of the passage, a sealing effect is achieved, preventing the generated steam from escaping out of the passage against the flow, and allowing it to quickly flow into the bottom opening. can lead.

Examples Embodiments of the invention shown in the drawings will be described below.

First, referring to Figure 1, the shell (1) has a cylindrical shape with an elliptical cross section extending in the horizontal direction, with a steam outlet (2) at the top and a concentrated liquid outlet (6) at the bottom. (3). Heating fluid supply port (4
) as well as the outlet (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 the end plate (8).

A plurality of plates (9) connect the shell (1) and the moving frame (
10) A bolt or the like is tightened by a means. As shown in FIG. 2, each plate (9) is approximately rectangular and has a heat transfer surface with a short heat transfer length (preferably 4 m or less) and through holes (11 ) (12). The plates (9) extend vertically, and in the state where their palms touch each other, all the through holes (11)
# and (12) are aligned, and the through hole (11) communicates with the heating fluid supply port (4), and the through hole (12) communicates with the heating fluid outlet (5).

These plurality of plates (9) come into contact with each other via gaskets, so that alternate passages (
A) (B) is formed.

(7) To explain in more detail, as can be clearly seen from Figure 3,
The heating fluid passage (A) is closed off to the internal space (C) of the shell (1) by a gasket (13) extending along the outer periphery of the plate (9), while the through hole (11
) (12) and therefore also with the supply (4) and the discharge (5) of the heating fluid. The passage (B) for the liquid to be evaporated is a partially cut out gasket) (
The internal space (C ) are in contact.

A header (17) equipped with a group of nozzles (16) for injecting the liquid to be vaporized into each passage (B) each has an opening (15,) at the top of the passage (B) as well as an opening at the side ( 1
5,) (153) is located so that the nozzle (16) is facing. In the illustrated example, the nozzle group is provided in three stages, but
A liquid circulation pump (19) is connected to the conduit (18) leading from the concentrate outlet (8) (3) to the header (17), which may be provided in two or four or more stages as necessary. . Liquid circulation pump (
19), there is a concentrate take-out pipe (20
) is further connected to a supply pipe (21) for the liquid to be evaporated.

Inside the shell (1), outside the area occupied by the plate (1), a steam outlet space (D) is defined which functions for the outlet of the steam generated in the passageway (B) and for mist separation. There is. The steam outlet space is defined not only in a part of the cylindrical shell (1) in the axial direction as shown in the figure, but also in the plate (1) in the cross section perpendicular to the axis (Fig. 2).
It can also be defined on both sides. (22) 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 is supplied from the supply port (4) provided in the shell (1) through the through hole (11) as shown by the solid line in FIG.
It flows into each passage (A) from (9) and flows out from the through hole (12) to reach the discharge port (5).

The liquid to be vaporized is as shown by the broken line in FIG.
Injected from the nozzle (16) into the passage (B)
It flows down in a thin film on the heat transfer surface of the plate (1) facing.

At this time, steam is generated by heating by the heating fluid flowing through the adjacent passage (A). The unevaporated liquid, that is, the concentrated liquid, falls from the lower opening (154) of the passageway (B) to the bottom of the shell (1), and is removed by the liquid circulation pump (20) to the outlet (3).
) is circulated through line (18) to header (17).

The concentrated liquid is taken out from the withdrawal pipe (20) as appropriate, and a certain amount of new liquid to be evaporated is supplied from the replenishment pipe (21) accordingly or independently.

The steam generated in the passage (B) flows through the opening (1
54) once flows out toward the steam derivation space (D),
The steam then heads towards the steam outlet (2), during which it follows a generally U-shaped (lO) path, but when changing direction from the lower opening (154) to the upper steam outlet (2), the As shown by the broken line in Figure 1, the mist separates from the steam and forms a shell (1).
stagnates at the bottom. If there is still mist mixed in the steam, it will be captured by the demister (22).

[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 vertical sectional view, and FIG.
FIG. 3 is an exploded perspective view showing how the plates overlap and the state of fluid flow. (1)--shell, (2')-steam outlet, (3)
-・Concentrate discharge port, (4) -Heating fluid supply port, (5)
- Heated fluid outlet, (9) - Plate, (11)
(12) - through hole, (13) (14,~143)・-
... Gasket, (151~15+) - Sekiguchi, (16
) - Nozzle, (1B) - Pipeline, (19) ---
- One-liquid circulation pump, (A) - Heating fluid passage, (B)
- Pathway for the liquid to be evaporated. (11) Figure 1

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; a plurality of vertically extending plates with short heat transfer lengths that close the space and alternately form second passages communicating with the supply port and the discharge port of the heating fluid; the first passage; a group of nozzles arranged in multiple stages for injecting liquid to be evaporated inward from the upper and side openings of the passageway; a vapor extraction space defined inside the shell and outside the plate; and The concentrated liquid (1) includes a liquid circulation pump connected to a pipe line leading from the discharge port to the nozzle group, and the vapor generated in the first passage is sent to the lower part of the first passage. 1. A plate type evaporator, characterized in that the steam is taken out from the opening through the steam outlet space and through the steam exhaust port.