JPH03137901A - Evaporator - Google Patents

Abstract

PURPOSE:To enable to prolong the contact time between a liq. to be treated and a heating body by providing a container with a spiral heating body in its interior and a heating body having an untreated liq. supply part on its exterior. CONSTITUTION:A heating tube 2 is provided on the exterior of an evaporator with a spray nozzle 4 as an untreated liq. supply member for supplying a liq. waste 3. The heating tube 2 is maintained at a high temp. by passing a high temp. vapor therethrough. The liq. waste 3 is then continuously sprayed from the spray nozzle 4 to attach the liq. particles 5 to the outer surface 6 of the upper heating tube 2a. In doing so, the screen of the liq. waste is formed over the entire periphery of the outer surface 6 and the liq. screen on the lower part of the outer surface 6 partially reduces into water droplets 7 which are gradually moved downwardly and fallen off from the lowest part of the heating tube 2. This enables the heating efficiency to be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a technique for heating, evaporating, and concentrating a liquid to be treated such as industrial wastewater.

[Conventional technology]

In order to heat the above-mentioned liquid to be treated, conventional evaporators bring the liquid to be treated into contact with a heating body such as a high-temperature heating plate or heating tube. Various types of evaporators are known, such as a vertical type, a horizontal type, and an inclined type.

[Problem to be solved by the invention]

However, in the conventional evaporator as described above, the contact time between the liquid to be treated and the heating body cannot be kept long, and therefore there is a problem that the evaporation efficiency is poor.

The present invention has been made to solve this problem, and aims to provide an evaporator that can improve evaporation efficiency by increasing the contact time between a liquid to be treated and a heating element that heats the liquid. purpose.

[Means to solve the problem]

The evaporator according to the present invention includes a spiral heating body that is heated, and a liquid to be treated supply member that supplies a liquid to be treated to the outer surface of the heating body.

The present invention also includes a container that can maintain negative pressure, a spiral heating element that is housed in the container and heated, and a container that is placed near the heating element and supplies the liquid to be treated to the outer surface of the heating element. The treatment liquid supplying member and a recovery device that recovers at least one of the vapor of the liquid to be treated evaporated in the container and the staying liquid remaining in the container may be provided.

In addition, a container is installed in each of the above-mentioned chambers, which is partitioned into multiple chambers in a multi-tiered manner and can maintain negative pressure, and the heating medium flows through the outer tube, and circulates while remaining in each chamber through the inner tube. A spiral double-tube heating tube through which the liquid to be treated flows, and a liquid to be treated that is placed near the double-tube heating tube and passes through the inner tube,
A liquid to be treated supply member that supplies the outer surface of the double-pipe heating tube, a vapor recovery device that recovers the vapor of the liquid to be treated that has evaporated in the chamber, and a stagnant liquid recovery device that recovers the stagnant liquid that remains in the chamber. It may also include a device.

Further, it is preferable that the liquid to be treated supply member is a spray nozzle that sprays the liquid to be treated.

[Effect]

In the present invention, since the heating body has a spiral shape,
Due to the surface tension of the liquid, the liquid to be treated that is supplied to the outer surface of the heating element falls down over a long period of time while adhering to the outer surface of the heating element while spiraling downward.

Furthermore, since the container housing the heating element can be maintained at a negative pressure, the liquid to be treated boils at a temperature below the boiling point of the liquid to be treated under atmospheric pressure, improving the rate of evaporation.

Furthermore, the efficiency of evaporation is further improved by making the heating tube into a double tube shape, partitioning the container into a plurality of chambers in a multi-stage manner, and creating a flow system for a multi-effect can.

Furthermore, if a spray nozzle sprays the liquid onto the outer surface of the heating element in the form of a mist, the liquid will uniformly adhere to the outer surface and easily evaporate.

〔Example〕

First Embodiment A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. As shown in the figure, the evaporator 1 according to the present embodiment includes a heating tube 2 as a spiral heating body, and
A spray nozzle 4 is provided on the outer surface of the heating tube 2 as a to-be-treated liquid supply member for supplying waste water 3 as a to-be-treated liquid. By supplying high-temperature waste water or steam into the interior of the heating tube 2, the heating tube 2 is always maintained at a high temperature.

The circular and coiled force tube 2 is erected so that the central axis of the spiral portion is in the vertical direction, and the spray nozzle 4
As shown in FIG.
It is positioned so as to be attached to the outer surface 6 of the upper heating tube 2a of the spiral heating tubes 2.

If the waste water 3 is continuously sprayed from the spray nozzle 4 and the spray droplets 5 are attached to the outer surface 6 of the upper heating tube 2a, a film of waste water is formed on the entire circumference of the outer surface 6. A part of the filtered water film at the lower part of the outer surface 6 becomes wavy water droplets 7 due to its own gravity and gradually moves downward while adhering to the lower part of the outer surface of the heating tube 2 (arrow A). Finally, it separates from the heating tube 2 at the bottom of the heating tube 2 and falls (arrow B). Therefore, according to the device 1 of the present embodiment, the water film and water droplets 7 attached to the outer surface 6 of the heating tube 2 are in contact with the heating tube '2 for a long time due to the surface tension of water, so that sufficient heating is possible. The evaporation is carried out while the evaporation efficiency is -
becomes very high. In the device 1 of this embodiment, it is possible to increase the contact time between the waste water and the heating tube 2 by two to three times as compared to the conventional device.

Second Embodiment FIGS. 3 to 5 are diagrams showing an evaporator 20 according to a second embodiment of the present invention. As shown in FIGS. 3 and 4, a container 21 that can be maintained at negative pressure has a cylindrical shape with a bottom, and a sealing lid 22 is attached to the upper opening. In this embodiment, the central axis of the spiral portion of the heating tube 23 as a spiral heating body that is housed in the container 21 and heated is in the vertical direction with respect to the container 21, and is shown by arrows C and D. As shown, it is constantly heated to high temperatures by waste water or steam. In this embodiment, the spray nozzle 24, which serves as a liquid-to-be-treated member disposed near the heating tube 23 and supplies the liquid to be treated to the outer surface of the heating tube 23, is disposed above the spiral center of the heating tube 23. The liquid sprayed from the spray nozzle 24 is uniformly attached to the upper spiral portion of the heating tube 23. The concentrated liquid 25 as a staying liquid that stays in the lower part of the container 21 due to evaporation in the container 21 is extracted by a circulation pump 26 communicating with the container 21, passes through a pipe 27, and is sprayed into the heating tube 23 by a spray nozzle 24. sprayed onto the surface. A pipe 28 for discharging steam inside the container 21 is attached to the lid 22 of the container 21.
A condenser 29 is connected to the other end, and by supplying cooling water to the shell 30 side (arrows E and F), the pipe 2
The steam in the pipe 31 communicating with the pipe 8 is condensed.

Distilled water 32 generated by condensation in the condenser 29 is stored in a closed distilled water tank 33 and then transferred to the extraction pump 3.
4, it is extracted from the system. At the top of the distilled water tank 33 is a pipe 35 to which a vacuum pump 36 is connected at the other end.
is connected. Therefore, by operating the vacuum pump 36, the pipe 35, the distilled water tank 33, and the pipe 31 of the condenser 29, which are in communication with the vacuum pump 36,
, the inside of the container 21 is maintained at negative pressure via the pipe 28.

The condenser 29, the distilled water tank 33, the extraction pump 34, and the vacuum pump 36 constitute a recovery device 40 that recovers the steam generated within the container 21.

Therefore, in the evaporator 20 configured as described above, the heating tube 23 is maintained at a high temperature while the circulation pump 26
When the liquid 25 accumulated in the container 21 is extracted and sprayed from the spray nozzle 24, the sprayed liquid adheres to the outer surface of the upper helical portion of the heating tube 23 and forms a water film, as in the first embodiment. While forming water droplets, they become wavy water droplets due to their own gravity, and while they remain attached to the outer surface of the heating tube 23, they gradually move downward in a spiral shape over a long period of time, thereby causing "evaporation and concentration of the liquid." The concentrated liquid falls to the lower part of the container 21 and stays there. On the other hand, the vapor generated by evaporation is extracted from the container 21 through the pipe 28 by the vacuum pump 36, and then transferred to the condenser 29, the distilled water tank 33, pump 34
It is extracted by It takes an evaporator! Regarding 20,
For example, the inside of the container 21 is approximately -750m by the vacuum pump 36.
Negative pressure up to mFIg allows evaporation to occur between 42°C and 60°C, accelerating the evaporation rate.

FIG. 5 shows the height relationship of the spray nozzle 24 with respect to the heating tube 23, and shows the relationship between the height of the spray nozzle 24 and the uppermost pipe 41a among the pipes 41 of the heating tube 23 arranged at a predetermined pitch in the vertical direction. If the spray nozzle 24 is installed at a predetermined height as shown by the solid line, the liquid to be treated that is sprayed in a fan shape from the spray nozzle 24 will leak outward (to the left in the figure) from the gaps between the pipes 41 and 41a. There isn't. However, if the position of the spray nozzle 24 is low as shown by the chain line in the figure,
A part of the sprayed liquid leaks outward from the gap and does not adhere to the surface of the heating tube 23, which is not preferable because the leaked liquid is not evaporated on the surface of the heating tube (see G in the figure).

In addition, in the second embodiment, a supply line 42 for continuously supplying the liquid to be treated is provided in the container 21, and a staying liquid recovery device (not shown) is provided for continuously extracting the concentrated staying liquid 25. You can. In this way, the evaporator 2
0 can be operated continuously for a long time.

Also, the above 1. The heating body in the second embodiment may be a spiral rod-shaped body that is heated by other means (for example, an electric heater) without using a tube.

Third Embodiment FIG. 6 is a diagram showing an evaporator 50 according to a third embodiment of the present invention, in which a container 51 that can be maintained at negative pressure is partitioned into a plurality of chambers in a multi-stage shape (n-stage shape). In this figure, the number of stages n is 3, and the top stage is the first stage chamber 100, and below this are the second stage chamber 200 and the third stage (nth stage) chamber 300.

A spiral double-tube heating tube 52 is installed in each chamber 100, 200, 300, and an outer tube 53 of this heating tube 52 is installed.
A heating medium for heating the outer tube 53 is passed through the inner tube 54, and a liquid to be treated that circulates while remaining in each chamber is passed through the inner tube 54.

That is, in the first stage chamber 100, hot water or steam (heating medium) from the heat source 55 is circulated in the outer tube 53 through a loop of the heat source 55, the pipe 56, the outer tube 53, and the pipe 57, and the tube 52 is heated. The liquid 1 stagnant in the chamber 100 is heated inside the inner tube 54.
10 is circulated through a loop including a pump 120, a pipe 125, an inner pipe 54, a nozzle supply pipe 130, and a spray nozzle 140, and is heated and evaporated on the outer surface of a double-pipe heating pipe 52. Note that the valve 12 provided in the pipe 125
6 is closed. The spray nozzle 140 serving as a member to supply the liquid to be treated sprays the supplied high-pressure staying liquid 110 onto the outer surface of the outer tube 53 .

The vapor that evaporates from the heated liquid on the surface of the outer tube 53 is
The steam is extracted from the steam extraction pipe 150 by a vacuum pump 500, which will be described later, and flows through the pipe 160.

A cover 170 is attached to the lower part of the opening of the steam extraction pipe 150 so that the liquid injected from the spray nozzle 140 does not directly enter the steam extraction pipe 150.

In the second stage chamber 200, the high temperature steam (heating medium) from the first stage chamber 100 is transferred to the steam extraction pipe 1 in the outer tube 53.
50, the pipe 160, and the outer tube 53 inside the chamber 200 in this order, and this steam is led to the vacuum pump 500. The stagnant liquid 210 in the chamber 200 is pumped through the pump 220, the pipe 225, and the chamber 2.
The liquid is circulated through a loop of the inner tube 54 for 00, the nozzle supply pipe 230, and the spray nozzle 240 serving as a liquid to be treated member, and is heated and evaporated on the outer surface of the heating tube 52. Note that the valve 226 of the pipe 225 is closed. The spray nozzle 240 and the cover 270 are the same as the spray nozzle 14.
0. It is similar to the cover 170, and the steam evaporated on the surface of the outer tube 53 inside the chamber 200 is extracted from the steam extraction pipe 250 by the vacuum pump 500 and flows into the pipe 260.

In the third-stage chamber 300, the high-temperature steam (heating medium) from the second-stage chamber 200 and the third-stage chamber 300 is supplied to the outer tube 53 through steam extraction pipes 250 and 350, pipes 260.3
60 and the outer pipe 53 inside the chamber 300, and this steam is led to the vacuum pump 500. Remaining liquid 310 in chamber 300
is the pump 320, the pipe 325, and the inner pipe 5 for the chamber 300.
4. The heating pipe 5 is circulated through a loop of the nozzle supply pipe 330 and the spray nozzle 340 as a liquid to be treated supply member.
It is heated and evaporated on the outer surface of 2. Note that the valve 326 of the pipe 325 is closed. spray nozzle 340,
The cover 370 includes the steam spray nozzle 140 and the cover 17
0, the steam evaporated on the surface of the outer tube 53 in the chamber 300 is transferred to the steam extraction tube 3 by the vacuum pump 500.
50 and flows into pipe 360. Room 200
The steam evacuated through each outer tube 53 of 300 and 300 is
After passing through the pipes 400 and 410, the capacitor 420
After being cooled and condensed by cooling water,
After being stored as distilled water 440 in the distilled water tank 430, it is extracted from the system by the extraction pump 450. tank 4
The gas phase part in 30 is connected to a vacuum pump 500, and this vacuum pump 500 connects the distilled water tank 430, the condenser 420, each outer pipe 53 of the chamber 200, 300, and the chamber connected to this outer pipe 53. Each of the chambers at 100°, 200° and 300° is maintained at a negative pressure.

The condenser 420, the distilled water tank 430, and the vacuum pump 500 constitute a vapor recovery device 600 that recovers the vapor of the liquid to be treated evaporated within the chambers 100, 200° 300. In addition, pumps 120, 220, and 320,
A stagnant liquid recovery device 7 that collects stagnant liquid in the chambers 100, 200° 300 using a valve 126゜226.326 and a pipe 125゜225.325 connected thereto.
00, and when the valves 126, 226, and 326 are opened by a predetermined amount while the evaporator 50 is in operation, the liquid in the upper stage gradually moves to the lower stage and is finally discharged from the system through the valve 326. Ru.

Therefore, in this third embodiment, since the container 51 has multiple stages, the flow becomes a multi-effect can flow, and the heat amount of the steam generated in the upper stage chamber can be used in the lower stage chamber, thereby increasing the evaporation efficiency. It is possible to realize improvements in heat efficiency and effective use of heat. Further, the present evaporator 50 can be applied to the concentration of high-concentration wastewater, product concentration, and the like.

In the third embodiment, the container 51 is divided into three stages and partitioned into three chambers, but any number of stages other than three stages may be used as long as there are a plurality of chambers.

In the first to third embodiments described above, the spray nozzle may be a ring-shaped spray nozzle having an inner ring diameter similar to that of the heating tube. Moreover, although the heating tube was installed upright and fixed, the heating tube may be placed horizontally and rotated. Further, this spiral heating tube is not limited to a circular shape.

Note that the same reference numerals in each figure indicate the same or corresponding parts.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

In the evaporator according to the first aspect, since the heating body to which the liquid to be treated is supplied to the outer surface is configured in a spiral shape, the liquid to be treated moves in a spiral while adhering to the outer surface of the heating body, and the liquid to be treated is The contact time between the liquid and the heating element becomes longer and sufficient evaporation occurs.

In the evaporator of the second aspect, in addition to the above-mentioned effects, since the container has a negative pressure, evaporation can be caused at a low temperature, and the evaporation rate is improved.

In the evaporator of claim 3, in addition to the effects of claims 1 and 2, since the container is partitioned into a plurality of chambers and double-pipe heating tubes are used, the amount of heat of the steam in the upper stage is transferred to the lower stage. can be used to further improve evaporation efficiency.

In the evaporator according to the fourth aspect of the present invention, the spray nozzle causes the liquid to adhere to the outer surface of the heating element in the form of a mist, so that the liquid becomes uniform on the outer surface and evaporation is promoted.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an evaporator showing a first embodiment of the present invention;
FIG. 2 is a front view of the same embodiment, FIGS. 3 to 5 are diagrams showing a second embodiment of the present invention, and FIG. 3 is a front view showing the structure of a container in which a heating tube is housed. Figure 4 is a circuit diagram of an evaporator equipped with the container shown in Figure 3, Figure 5 is an enlarged view showing the height positional relationship of the spray nozzle with respect to the heating tube, and Figure 6 is a diagram showing the third embodiment of the present invention. FIG. 2 is a circuit diagram of the evaporator shown in FIG. 1.20.50... Evaporation device, 2.23... Heating body (heating tube), 3.25,110,210.310... Liquid to be treated, 4
．． 24,140,240,340... To be treated liquid supply member (spray nozzle), 21.51... Container, 25... Remaining liquid (concentrated liquid), 40... Recovery device, 52... Double pipe heating tube, 53... Outer tube, 54... Inner tube, 100.200.300... Chamber, 600... Steam recovery device, 700... Remaining liquid recovery device.

Claims (1)

[Scope of Claims] 1. An evaporation device characterized by comprising a spiral heating body that is heated, and a liquid to be treated supply member that supplies liquid to be treated to the outer surface of this heating body. 2. A container that can be maintained at negative pressure, and a container that is stored in the container,
A spiral heating body to be heated, a liquid to be treated member disposed near the heating body to supply the liquid to be treated to the outer surface of the heating body, and vapor of the liquid to be treated by evaporation within the container. and a recovery device for recovering at least one of the remaining liquid remaining in the container. 3. A container that is partitioned into a plurality of chambers in a multi-tiered manner and can be maintained at negative pressure, and installed in each of the above chambers, with the heating medium flowing through the outer tube and circulating while remaining in each chamber through the inner tube. A spiral double-pipe heating tube through which the liquid to be treated flows, and a spiral heating tube arranged near the double-pipe heating tube to direct the liquid to be treated that has passed through the inner tube onto the outer surface of the double-pipe heating tube. The present invention is characterized by comprising a liquid to be treated supplying member, a vapor recovery device for recovering the vapor of the liquid to be treated evaporated in the room, and a liquid recovery device for recovering the liquid remaining in the room. Evaporation equipment. 4. Claim 1, 2 or 3, wherein the liquid to be treated supplying member is a spray nozzle that sprays the liquid to be treated.
Evaporation device as described.