JPH0557001B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-effect distillation apparatus suitable for producing distilled water mainly for medical use and pure steam.

(Prior art) For example, as a distilled water production device, a first system that generates water vapor from raw water by exchanging heat between high temperature primary steam and low temperature raw water supplied from a first passage for supplying raw water. Heat exchange is performed between the heat exchanger and the steam generated in the first heat exchanger and the unevaporated raw water to generate steam from the raw water 1
Alternatively, a configuration has already been proposed in which a series of two or more second heat exchangers is set, and each heat exchanger is set to have approximately the same capacity (for example, Japanese Patent Application No. 188957/1989).
60-78686).

However, with this configuration, as distillation progresses through each heat exchanger, the flow rate of unevaporated raw water decreases, so as the final stage of distillation approaches, a predetermined amount of raw water is not supplied to the heat exchanger. As a result, the generated steam becomes overheated (superheated) and problems such as hunting occur. Moreover, this causes a problem that it becomes impossible to stably obtain distilled water having uniform purity.
Furthermore, if the flow rate in the heat exchanger is extremely reduced, impurities contained in the raw water will stick to the wall surface where heat exchange is performed, resulting in a problem that the heat exchange efficiency will decrease.

On the other hand, if the overall flow rate is increased in order to prevent the above problems, the flow rate of raw water in the heat exchanger during the initial stage of distillation will become excessive, causing a problem that efficient heat exchange cannot be performed. . Also, in order to ensure the flow rate of raw water in the later stages, it is possible to install a pump and recycle the raw water, but the heated raw water is at a high temperature (usually
(100℃ or higher), and it is difficult to obtain a suitable pump that can withstand such high temperatures at a low cost. Furthermore, if a pump is provided, not only a driving device and a power source are required for the pump, but also problems arise that increase maintenance costs.

(Objective of the Invention) To supply an appropriate amount of heated liquid (for example, water) to each heat exchanger with a simple configuration without providing a drive mechanism such as a pump. The aim is to thereby prevent problems such as the generation of overheated steam and hunting, while also preventing a decrease in heat exchange efficiency and ensuring stable distillation.

(Structure of the Invention) The present invention provides a first method for generating steam from the heated liquid by performing heat exchange between a high temperature heating medium and a low temperature heated liquid supplied from a first passage for supplying the heated liquid. 1 or 2 for generating steam from the heated liquid by exchanging heat between the heat exchanger and the vapor generated in the first heat exchanger and the heated liquid that has not evaporated;
In a multi-effect distillation apparatus having the above series of second heat exchangers, each heat exchanger having approximately the same capacity; a bypass branching from the first passage;
Each heat exchanger is connected to the downstream side of the orifice of the second passage to supply the unevaporated heated liquid to the second heat exchanger via the orifice, and the heated liquid is supplied to the second heat exchanger. This is a multi-effect distillation apparatus characterized in that the amount of heated liquid supplied to the vessel is approximately equal.

(Example) In FIG. 1 showing the case where the multi-effect distillation device according to the present invention is adopted as a distilled water production device, a heating medium inlet 12 of a heat exchanger 11 is connected to a boiler (not shown) at 158°C (5Kg/cm ^{2 ).}・g)～174℃(8Kg/
A passage 13 into which heating steam (primary steam) of about 1 cm ² ·g) is introduced is connected. A passage 14 branching from the passage 13 is a heating medium inlet 1 of the preheater 15.
6, and the heating medium outlet 17 of the preheater 15 is connected to the discharge path 1 having a trap 18 in the middle.
It communicates with the outside via 9. Also heat exchanger 11
A heating medium inlet 20 for heating steam introduced into the interior also communicates with the outside via a discharge passage 19. The trap 18 is designed to drain water only when water accumulates, and close when water does not accumulate and exists as steam.

The leading end of the passage 22 is connected to the heated medium inlet 21 of the preheater 15 , and the rear end of the passage 22 is connected to the heated medium outlet 24 of the condenser 23 . The condenser 23 is a heat exchanger shared with another path 25, and raw water is supplied from a path 27 connected to the heated medium inlet 26 at a pressure of about 5 to 8 kg/cm ² ·g. ing.

On the other hand, the heated medium outlet 28 of the preheater 15 is connected to the heated medium inlet 3 of the heat exchanger 11 via a passage 29.
0, and the water introduced from the heated medium inlet 30 in the heat exchanger 11 is connected to the heat exchange pipe 31.
It is adapted to be heated by heating steam from the heating medium inlet 12 via the heating medium inlet 12 . A flushing chamber 32 is provided at the lower end of the heat exchanger 11, and a heated medium outlet 33 formed at the lower end of the flushing chamber 32 has a passage 35 having an orifice 34 (or valve) for restricting the flow rate in the middle. One end of is connected. The other end of the passage 35 is connected to the heated medium inlet 21a of the next stage preheater 15a. A mist separator 37 is provided at a steam outlet 36 formed on the side wall of the flushing chamber 32, and a steam outlet 38 of the mist separator 37 passes through a passage 39 to heat the heating medium inlet 16a of the preheater 15a and the heat exchanger 11a. Media inlet 12a
is connected to. Note that the mist separator 37 separates droplets in the vapor using a cyclone method.

The heat exchanger 11a, which is the second-stage distillation device, has roughly the same structure as the heat exchanger 11, and is set to the same capacity, and in FIG. There is. Although the preheater 15a is set to have a smaller capacity than the preheater 15, it has the same structure as the preheater 15, and the parts corresponding to the preheater 15a have an "a" in the code.
is attached. Note that the heating medium outlet of the preheater 15a is connected to the heating medium inlet 41a of the heat exchanger 11a via a passage 40a.

Furthermore, a heat exchanger 11b is installed as a third stage distillation device.
A preheater 15b is provided, and a heat exchanger 11b is provided.
and preheater 15b have the same connection configuration as between heat exchanger 11 and preheater 15 and between heat exchanger 11a and preheater 15a, respectively, and in FIG. .
However, the heating medium outlet 20a of the heat exchanger 11a is
It is connected to the heating medium inlet 12b of the heat exchanger 11b via a passage 43a having an orifice 42a in the middle. The heat exchanger 11b is set to have exactly the same shape and capacity as the heat exchanger 11a,
Further, the preheater 15b has exactly the same shape and capacity as the preheater 15a.

Heat exchanger 11c and preheater 1 as the fourth stage
5c is provided, and the heat exchanger 11c and the preheater 15c are the heat exchanger 11a and the preheater 1, respectively.
5a, heat exchanger 11b, and preheater 15b, the connection configuration is exactly the same as that between heat exchanger 11b and preheater 15b, and in FIG. The heat exchanger 11c has the same shape and capacity as the heat exchangers 11a and 111b, and the preheater 15c has the same shape and capacity as the heat exchangers 11a and 111b.
It is set to have exactly the same shape and capacity as b.

A passage 35c connected to the heated medium outlet 33c of the heat exchanger 11c has an orifice 45 in the middle, and the other end of the passage 35c is open to the outside. Also, the passage 43c and the passage 39 of the heat exchanger 11c
c are respectively connected to heating medium inlets 46 and 47 of the condenser 23, and a heating medium outlet 48 of the condenser 23 is connected via a passage 49 to a tank for distilled water (not shown).

Furthermore, in FIG. 1, a bypass 50 branches off from the passage 22, so that half of the raw water coming out of the heated medium outlet 24 of the condenser 23 flows to the bypass 50 side. The other end of the bypass 50 is 3
The main branch paths 51, 52, and 53 are branched, and the branch 51 is connected to the orifice 34 and the heated medium inlet 21a.
It is connected to a passage 35 in between. Branch road 5
2 is connected to the working fluid inlet of the injector 54, and the outlet of the injector 54 is connected to the orifice 3.
4a and the heated medium inlet 21b, the passage 35
connected to a. The branch passage 53 is connected to the working fluid inlet of the injector 55, and the outlet of the injector 55 is connected to the passage 35b between the orifice 34b and the heated medium inlet 21c. Further, a branch passage 56 branching from the passage 35b is connected to another inlet of the injector 54, and a branch passage 57 branching from the passage 35c between the heated medium outlet 33c and the orifice 45 is connected to another inlet of the injector 54.
It is connected to another entrance of 5.

Note that the bypass 50, branch roads 51, 52, 53,
Pipe diameters of branch passages 56 and 57 and injector 54,
The capacity of 55 is set so that raw water is distributed at a predetermined ratio during the operation described below.

Next, the operation will be explained. First, heated steam is supplied from the passage 13 into the heat exchanger 11 and the preheater 15 . Next, raw water (for example, highly purified water that has already been subjected to ion exchange and other treatments) is supplied to the condenser 23 from the passage 27 . As an example, assume that the supply amount from the passage 27 at this time is 1100/h, and that the design flow rate of each heat exchanger 11a, 11b, and 11c is set to 550/h. The raw water that has passed through the condenser 23 is supplied to the preheater 15 via the passage 22, but by distributing half of the raw water at 550/h to the bypass 50 branching from the passage 22, the amount of raw water to the preheater 15 is reduced. The supply amount will be 550/h. The raw water that has been preliminarily heated by the heated steam from the passage 13 in the preheater 15 is transferred from the heated medium inlet 30 to the heat exchanger 11.
will be introduced in Heat exchange pipe 3 in heat exchanger 11
1, the raw water is heated by the heated steam introduced from the heating medium inlet 12, and a portion of it evaporates mainly within the flushing chamber 32.
On the other hand, the heated steam from which heat has been removed in the heat exchanger 11 is condensed and becomes a liquid, and is discharged to the outside through the discharge passage 19 together with the water that has become a liquid in the preheater 15.

The water vapor generated in the flushing chamber 32 is removed in droplets by a mist separator 37, and then passed through a passage 39 to a heat exchanger 11a and a preheater 15a.
(The pressure is about 3Kg/
^cm2・g). The raw water that has not evaporated in the flushing chamber 32 is introduced into the preheater 15a as a medium to be heated, with its flow rate being adjusted by an orifice 34. Here, the amount of water vapor led from the heat exchanger 11 to the next stage via the passage 39 is approximately 250/
It is h. Therefore, the amount of raw water introduced to the next stage via the passage 35 is approximately 300/h. One side aisle 22
Of the 550/h of raw material water distributed from /h. The raw water introduced into the preheater 15a is preliminarily heated by removing heat from the water vapor in the preheater 15a, and is then used in the second stage distillation device. It is introduced into the heat exchanger 11a as a medium to be heated. A portion of the raw water, which has absorbed heat from the steam while flowing down inside the heat exchange pipe 31a of the heat exchanger 11a, evaporates mainly within the flushing chamber 32a. On the other hand, the distilled water that has been deprived of heat and condensed in the preheater 15a passes through the passage 40a to the heat exchanger 1.
1a, heat is given to the raw water in the heat exchanger 11a, and the distilled water from the heating medium inlet 12a is condensed and discharged to the passage 43a.

In the second stage heat exchanger 11a, in addition to the raw water from the heat exchanger 11, raw water from another route via the bypass 50 and the branch path 51 is added, and as a result, it is introduced into the preheater 15a and the heat exchanger 11a. The amount of raw water used is a predetermined amount, that is, 550/h. As a result, highly efficient heat exchange is performed within the heat exchanger 11a as designed.

The heat exchanger 11b, which is the third stage distillation device, has 250/250/250
In addition to the distilled water of h, water vapor whose droplets have been separated by the mist separator 37a is introduced in an amount equivalent to 250/h (pressure is approximately 2 Kg/cm ² ·
g). Therefore, the amount of raw water that has not evaporated in the flushing chamber 32a is 300/h, and the amount of raw water that has not evaporated in the flushing chamber 32a is 300/h, and the amount of raw water that has not evaporated in the flushing chamber 32a is 300/h.
b. On the other hand, it was distributed to bypass 50.
Of the raw water of 550/h, 100/h goes to branch road 52.
is distributed, and the preheater 15
100/h of raw water is added to b via the injector 54. Also, half of the raw water that did not evaporate in the heat exchanger 11b, which will be described later, was 150/h.
is distributed from the passage 35b and introduced into the preheater 15b via the branch passage 56 and the injector 54. Therefore, the total amount of raw water introduced into the preheater 15b as a medium to be heated is 550/h, and these raw water introduced into the preheater 15b are
It is introduced as a medium to be heated into the heat exchanger 11b, which is the second distillation device.

The behavior of the raw water, steam, and distilled water thereafter is the same as that in the second stage. The amount of raw water introduced in the third stage heat exchanger 11b is a predetermined amount,
That is, it becomes 550/h, and as a result, highly efficient heat exchange is performed within the heat exchanger 11b as designed.

Steam equivalent to 250/h of water evaporated in the flushing chamber 32b in the heat exchanger 11b is introduced as a heating medium into the heat exchanger 11c and the preheater 15c via the passage 39b (pressure is approximately 1 Kg/cm ² ·g). Also, the raw water of 300/h that has not been evaporated is introduced into the preheater 15c as a medium to be heated through the passage 35b. However, as mentioned above, raw water 300/h
Of these, 150/h is from branch road 56 to injector 5
Therefore, the amount of raw water introduced from the flushing 32b to the preheater 15c is 150/h.
becomes. On the other hand, the remaining 200/h of the raw water distributed to the bypass 50 is distributed to the branch path 53, and the remaining 200/h is distributed to the preheater 15b.
raw water is added via the injector 55. Also, 200/h of the raw water that did not evaporate in the heat exchanger 11c, which will be described later, is distributed from the passage 35c and introduced into the preheater 15c via the branch passage 57 and the injector 55. Therefore, the preheater 15
The total amount of raw water introduced as a heating medium into c is
550/h, and the raw water introduced into the preheater 15c is transferred to the heat exchanger 11c, which is the fourth stage distillation device.
is introduced as a heated medium.

The behavior of the raw water, water vapor and distilled water thereafter is the same as that in the second and third stages. The amount of raw water introduced into the fourth stage heat exchanger 11c is a predetermined amount, that is, 550/h, and as a result, highly efficient heat exchange as designed is performed within the heat exchanger 11c.

Steam equivalent to 250/h of water evaporated in the flushing chamber 32c in the heat exchanger 11c is introduced as a heating medium into the condenser 23 via the passage 39c (pressure is about atmospheric pressure), and 300/h that is not evaporated The raw water is discharged to the outside through the passage 35c.
However, as mentioned above, out of 300/h of raw water
Since 200/h is distributed from the branch path 57 to the injector 55, the amount of raw water discharged from the flushing chamber 32c to the outside is 100/h. The raw water that is discharged contains concentrated impurities that were originally contained in the distilled water produced at 1000/h.

On the other hand, the heat exchanger 11c which is the fourth stage distillation device
Along with the steam equivalent to 250/h of water generated in , the distilled water 750/h generated in the first to third stage distillers is sent to the condenser 23 via the passage 43c.
h is supplied as a heating medium. capacitor 23
A total of 1000/h of distilled water gives heat to the raw water from the passage 27 and the liquid flowing through the other passage 25.
It is sent to a tank (not shown) via a passage 49.

(Effects of the Invention) Heat exchange is performed between the high temperature heating medium (e.g. steam) and the low temperature liquid to be heated (e.g. water) supplied from the first passage (for example, passage 22) for supplying the liquid to be heated. A first step that generates steam from a heated liquid.
A heat exchanger (for example, heat exchanger 11) and one or more heat exchangers that generate steam from the heated liquid by exchanging heat between the steam generated in the first heat exchanger and the unevaporated heated liquid. In a multi-effect distillation apparatus having a series of second heat exchangers (for example, heat exchanger 11a), each heat exchanger having approximately the same capacity; a bypass 50 branching from the first passage;
A second passage (for example, a passage 35) is connected to the downstream side of the orifice 34 to supply the unevaporated heated liquid to the second heat exchanger via the orifice 34 to supply the heated liquid to the second heat exchanger. By doing so,
Since the amount of heated liquid supplied to each heat exchanger is approximately equal; (a) there is no need to provide a drive mechanism such as a pump;
With a simple configuration, it becomes possible to supply an appropriate amount of heated liquid to each heat exchanger.

(b) Since the liquid film on the surface of the pipe in the heat exchanger will not break, problems such as generation of overheated steam and hunting can be prevented, and stable distillation can be performed and distillation of consistent quality can be achieved. water is available.

(c) Since an appropriate amount of liquid to be heated is supplied to each heat exchanger, the heat exchange surface of the heat exchanger does not dry out, and as a result, impurities contained in the raw water are removed from the heat exchange surface. This prevents problems such as sticking and deteriorating heat exchange efficiency.

(d) Since the size (capacity) of each heat exchanger can be made the same, manufacturing costs can be reduced.

(e) Since it has a multi-stage structure, the amount of primary steam for heating can be reduced.

(f) Since the bypass 50 branching from the first passage 22 is connected to the downstream side of the orifice 34 of the second passage 35, the amount of the heated medium exiting from the heated medium outlet 33 of the flushing chamber 32 can be optimally controlled. An appropriate amount of the medium to be heated can be supplied to the second heat exchanger 11a.

(Another Embodiment) (a) The present invention is not limited to the case where it is employed in a four-stage multi-effect distillation apparatus, and may be applied as long as there are two or more stages. It is usually effectively employed in cases of 3 to 7 stages.

(b) The injector 54 and the branch passage 56 may be omitted and the branch passage 52 may be directly connected to the passage 35a.
In this case, in the above embodiment in which the raw water supply rate is 1100/h, the feed rate of raw water is 250/h to the branch path 52.
, and 50/h of raw material water may be distributed to the branch path 53.

(c) Furthermore, the injector 55 and branch path 57 can also be omitted. In this case, since the amount of discharge to the outside from the passage 35c is 300/h, the total amount of raw water supplied needs to be 1300/h. In this case, 750/h of the 1300/h of raw water is distributed to the bypass 50, and the
It is necessary to distribute 250/h of that to 3.

(d) The tube plates provided at both ends of the heat exchange pipe 31 of the heat exchanger 11 may have a double structure. Further, other heat exchangers may have a double tube plate structure.

(e) The present invention is not limited to the case where it is employed for the distillation of water, but can also be employed for the distillation of other fluids.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a multi-effect distillation apparatus according to the present invention. 11...first heat exchanger, 11a...heat exchanger (second
example of heat exchanger), 22...first passage, 35...second
Passage, 50...bypass.

Claims (1)

[Claims] 1. A first system for generating steam from the heated liquid by performing heat exchange between the high temperature heating medium and the low temperature heated liquid supplied from the first passage for supplying the heated liquid.
a series of one or more second heat exchangers that exchange heat between the heat exchanger and the steam generated in the first heat exchanger and the unevaporated heated liquid to generate steam from the heated liquid; In a multi-effect distillation apparatus having: and in which each heat exchanger is set to have approximately the same capacity;
A bypass branching from the first passage is connected to the downstream side of the orifice of the second passage, which supplies the liquid to be heated that has not evaporated to the second heat exchanger via the orifice, so that the liquid to be heated is supplied to the second heat exchanger. 1. A multi-effect can distillation apparatus characterized in that by supplying liquid, the amount of heated liquid supplied to each heat exchanger is approximately equal.