JP2017018927A - Multi-utility type water producing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-utility type water producing apparatus in which, because an existing thermo-compressor can be adopted for boosting the pressure of the vapor in the latter stage evaporation can, the performance can be improved with a simple configuration.SOLUTION: A multi-utility type water producing apparatus 1 comprises evaporation cans 2 disposed in a plurality of stages 2A to 2Z, and a plurality of thermo-compressors 3. The evaporation cans 2 are so configured as to evaporate raw water from outside as well as to cool and condense the vapor in order to produce pure water. The plurality of thermo-compressors 3 include a suction thermo-compressor 3A for sucking the vapor in the evaporation cans 2 at the m-th stage 2M and boosting the pressure, and a feed thermo-compressor 3Z for sucking the vapor whose pressure is boosted by the suction thermo-compressor 3A and further boosting the pressure, followed by feeding into the evaporation cans 2 at the foremost stage 2A.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-effect fresh water generator.

  The multi-effect freshwater generator, which is one of the seawater desalination plants, has advantages in that it is more resistant to deterioration of seawater quality and easier to maintain and inspect than a freshwater generator using a reverse osmosis membrane. On the other hand, the multi-effect fresh water generator also has a disadvantage that it consumes a large amount of energy. For this reason, seawater desalination plants that consume large amounts of energy, such as multi-effect freshwater generators, are widely used in Gulf Arab countries and other countries with abundant energy resources.

  Such a multi-effect fresh water generator is a kind of apparatus that desalinates seawater by an evaporation method, in other words, a kind of apparatus that obtains pure water by cooling steam obtained by evaporation of seawater. The multi-effect freshwater generator has not only a multi-stage evaporator for evaporating seawater, but also a low-pressure steam in one of the second and subsequent evaporators in order to obtain pure water more efficiently. It is also equipped with a thermocompressor that boosts pressure and supplies it to the first evaporator. The thermocompressor sucks and raises the pressure of low-pressure steam using high-pressure drive steam that is separate steam.

  By the way, in a seawater desalination plant equipped with a thermocompressor such as a multi-effect fresh water generator, the evaporator connected to the thermocompressor is the mth stage, and the low-pressure steam sucked from the mth stage evaporator Assuming that the flow rate is D, the obtained pure water theoretically increases by m · D compared to a multi-effect fresh water generator not equipped with a thermocompressor. That is, in order to increase the obtained pure water, it is conceivable to connect a thermocompressor to a later stage evaporator and increase the flow rate D of the low-pressure steam sucked. For this reason, as a conventional seawater desalination plant, a seawater desalination apparatus has been proposed in which the flow rate D of low-pressure steam sucked into a thermocompressor is increased (see, for example, Patent Document 1).

JP 2012-148203 A

  On the other hand, the thermocompressor connected to the later evaporator is required to increase the pressure of the sucked low-pressure steam. This is because the evaporator is a multiple effect type, and the vaporizer at a later stage has a lower pressure. For this reason, since such a thermocompressor requires a pressure increase exceeding the performance of the existing thermocompressor, the existing thermocompressor cannot be employed. Therefore, in order to adopt an existing thermocompressor and to have a simple configuration, the evaporator connected to the thermocompressor is limited to the previous one, so the obtained pure water cannot be increased sufficiently, and as a result There was a problem that the performance could not be improved.

  Therefore, the present invention has an object to provide a multi-effect fresh water generator capable of improving performance with a simple configuration by adopting an existing thermocompressor to increase the pressure of steam in a subsequent evaporator. And

In order to solve the above-mentioned problem, a multi-effect fresh water generator according to the first invention is a multi-effect fresh water generator comprising evaporators arranged in a plurality of stages and a plurality of thermocompressors,
The evaporator is configured to evaporate raw water from outside and obtain pure water by cooling and condensing steam.
The plurality of thermocompressors sucks and boosts the vapor of the evaporators in the second and subsequent stages, and further evaporates after boosting the steam boosted by the suction thermocompressors, And a supply thermocompressor to be supplied to.

  Further, in the multi-effect freshwater generator according to the second invention, the plurality of thermocompressors in the multi-effect freshwater generator according to the first invention is three or more thermocompressors, and the pressure is increased by the suction thermocompressor. It has an intermediate thermocompressor that sucks and raises the generated steam and sucks it to the supply thermocompressor.

  Further, the multi-effect fresh water generator according to the third invention is the multi-effect fresh water generator according to the first or second invention, wherein the multi-effect fresh water generator is connected to all of the plurality of thermocompressors and driven for boosting. A driving steam source for supplying steam is provided.

  According to the multi-effect fresh water generator, the performance can be improved with a simple configuration because the existing thermocompressor can be used to increase the pressure of the vapor in the subsequent evaporator.

1 is an overall configuration diagram of a multiple-effect fresh water generator according to Embodiment 1 of the present invention. It is a block diagram of the thermocompressor with which the multi-effect fresh water generator is provided. It is a graph which shows the relationship between each evaporator and the pressure and temperature of those vapor | steam. It is a schematic block diagram of the multiple effect type fresh water generator which concerns on the Example of this invention. It is a schematic block diagram of the multiple effect type fresh water generator which concerns on a comparative example. It is a schematic block diagram of the multiple effect type fresh water generator concerning Embodiment 2 of this invention. It is a schematic block diagram which shows the modification of the multi-effect type fresh water generator.

[Embodiment 1]
Hereinafter, a multi-effect fresh water generator according to Embodiment 1 of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, this multi-effect fresh water generator has evaporators 2 arranged in a plurality of stages 2 </ b> A to 2 </ b> Z for obtaining pure water from an external raw water (for example, seawater) by an evaporation method. It is. The multi-effect fresh water generator 1 includes a plurality of thermocompressors 3 and a drive steam supply unit 9 (an example of a drive steam source) for driving these thermocompressors 3.

The inside of each evaporator 2 is divided into an upstream evaporation chamber 4 and a downstream storage chamber 8 by a partition wall 7 provided with a demister 7d at a predetermined height or more.
In the evaporation chamber 4, steam is supplied from one of a plurality of thermocompressors 3 (which will be described later in detail as a supply thermocompressor 3 </ b> Z) to the heat transfer pipe 5 in the first stage 2 </ b> A, and the other stage is 2 </ b> B to 2Z. Steam is supplied from the evaporator 2 to the heat transfer tube 5. On the other hand, raw water is sprayed from the spreader 6 to the heat transfer tube 5. Thereby, the steam in the heat transfer tube 5 is cooled and partly becomes condensed water, and part of the sprayed raw water is evaporated to become steam. This vapor fills not only the evaporation chamber 4 but also the storage chamber 8 through the demister 7d. Of the sprayed raw water, the raw water that has not evaporated is accumulated in the lower part of the evaporation chamber 4 as concentrated raw water. On the other hand, the condensed water in the heat transfer tube 5 is accumulated in the lower portion of the storage chamber 8 as pure water.

  The front and rear evaporation chambers 4 are connected by a raw water transfer pipe 10, and the front and rear storage chambers 8 are connected by a pure water transfer pipe 11. The pure water transfer pipe 11 in the foremost stage 2A branches to a condensate pipe 12. The evaporation chamber 4 of the last stage 2Z is connected to a concentrated raw water discharge pipe 13 that discharges the concentrated raw water, and the storage chamber 8 of the last stage 2Z is connected to a pure water extraction pipe 14 that takes out pure water. The condensate pipe 12 is provided with a condensate pump 22, the concentrated raw water discharge pipe 13 is provided with a blow-down pump 23, and the pure water discharge pipe 14 is provided with a production water pump 24.

  The raw cooling water is guided to the raw cooling water supply pipe 15 in the storage chamber 8 of the last stage 2Z, and the steam in the storage chamber 8 is cooled to be condensed water. As a result, the temperature of the cooling raw water rises and becomes simply raw water. A part of the raw water is discharged by the raw water discharge pipe 16, and the others are branched from the raw water discharge pipe 16 and supplied to the sprayer 6 of each evaporator 2 by the raw water supply pipe 17 provided with a makeup pump 27. Supplied. The raw water supplied to the spreader 6 is heated by a heater (not shown) provided in the raw water supply pipe 17.

  The steam in the m-th storage chamber 8 (must be the second and subsequent stages) 2M storage chamber 8 is boosted by a plurality of (two in the first embodiment) thermocompressors 3 and is supplied to the heat transfer tube 5 in the foremost stage 2A. Supplied. As shown in FIG. 2, each of the thermocompressors 3 includes a suction unit 31 for sucking steam, a drive unit 32 connected to the drive steam supply unit 9 and supplied with drive steam, and the suction unit 31 and the drive. It has a body 34 provided with the portion 32, a sleeve 35 provided on the downstream side of the body 34, and a diffuser 36 connected to the downstream side of the sleeve 35. The drive unit 32 includes a nozzle unit 33 disposed inside the body 34. The nozzle portion 33 reduces the pressure inside the body 34 by making the flow of driving steam inside the body 34 a supersonic flow. Vapor is sucked from the suction portion 31 due to the decrease in pressure.

Hereinafter, the arrangement of the plurality of thermocompressors 3 that is the gist of the present invention will be described.
As shown in FIG. 1, the plurality of thermocompressors 3 sucks the steam in the m-th stage 2M storage chamber 8 and sucks the steam boosted by the suction thermocompressor 3A. And a supply thermocompressor 3 </ b> Z that supplies the heat transfer pipe 5 of the front stage 2 </ b> A after further boosting. The m-stage 2M storage chamber 8 and the suction part 31 of the suction thermocompressor 3A are connected by a steam suction pipe 18, and the diffuser 36 of the suction thermocompressor 3A and the suction part 31 of the supply thermocompressor 3Z are connected by a steam relay pipe 20. The diffuser 36 of the supply thermocompressor 3Z and the heat transfer pipe 5 of the foremost stage 2A are connected by a steam supply pipe 19. In other words, the plurality of thermocompressors 3 are connected in multiple stages. The drive units 32 of the suction thermocompressor 3A and the supply thermocompressor 3Z constituting the plurality of thermocompressors 3 are all connected to one drive steam supply unit 9.

  Since these evaporators 2A to 2Z are multi-effect types, as shown in FIG. 3, the temperature T and the pressure P of the vapor in the evaporator 2 decrease in order from the front stage 2A to the last stage 2Z. For this reason, the vapor pressure P in the evaporator 2 is high when it is the foremost stage 2A, and is low when it is the m-th stage 2M sucked by the suction thermocompressor 3A. Accordingly, the plurality of thermocompressors 3 are required to increase the pressure of the sucked steam from the pressure at the m-th stage 2M to the pressure at the foremost stage 2A. When the m-th stage 2M is a later stage, the required step-up ΔP becomes large. Therefore, the conventional thermocompressor 3 may have insufficient performance if the conventional thermocompressor 3 is used. Therefore, in the present invention, as shown in FIG. 3, by dividing the required boost ΔP by the plurality of thermocompressors 3A, 3Z, the boosts Δp1, Δp2 required for the individual thermocompressors 3 are reduced, The existing thermocompressor 3 can be used.

Here, in the present invention, the fact that the existing thermocompressor 3 can be employed will be described using the example of FIG. 4 and the comparative example of FIG.
The multi-effect fresh water generator 1 according to the example of FIG. 4 is the m-th stage 2M in which the steam in the storage chamber 8 is sucked by the suction thermocompressor 3A in the multi-effect fresh water generator 1 according to the first embodiment. Is the 9th stage 2I. On the other hand, the multi-effect fresh water generator according to the comparative example of FIG. 5 is configured by a single thermocompressor instead of a plurality of thermocompressors 3 as in the above embodiment.

  The steam temperature T and pressure P in each of the evaporators 2 of the above examples and comparative examples are as shown in Table 1 below.

実施例および比較例のサーモコンプレッサ３は、いずれも、９段目２Ｉの貯留室８から吸引した蒸気を、１２．３４［ＫＰａ］（９段目２Ｉ）から５１．３３［ＫＰａ］（最前段２Ａ）まで昇圧させることが要求される。実施例では、図４に示すように、この要求される昇圧ΔＰを２つのサーモコンプレッサ３（吸引サーモコンプレッサ３Ａおよび供給サーモコンプレッサ３Ｚ）で分担する。具体的には、吸引サーモコンプレッサ３Ａで蒸気を１２．３４［ＫＰａ］（９段目２Ｉ）から例えば２６．１５［ＫＰａ］まで昇圧させ、供給サーモコンプレッサ３Ｚで蒸気をこの２６．１５［ＫＰａ］から５１．３３［ＫＰａ］（最前段２Ａ）まで昇圧させる。この場合、吸引サーモコンプレッサ３Ａの圧縮比（吸引した蒸気の圧力に対する供給した蒸気の圧力）が２．１２となり、供給サーモコンプレッサ３Ｚの圧縮比が１．９６となる。既存のサーモコンプレッサ３の圧縮比は２．５程度までなので、上記実施例では、吸引サーモコンプレッサ３Ａおよび供給サーモコンプレッサ３Ｚに、いずれも既存のサーモコンプレッサ３が採用可能となる。これに対して、比較例では、図５に示すように、単一のサーモコンプレッサ３００により構成されるので、上記要求される昇圧ΔＰを複数のサーモコンプレッサ３で分担しない。具体的には、単一のサーモコンプレッサ３００で蒸気を１２．３４［ＫＰａ］（９段目２Ｉ）から５１．３３［ＫＰａ］（最前段２Ａ）まで昇圧させる。この場合、単一のサーモコンプレッサ３００の圧縮比が４．１６となる。既存のサーモコンプレッサ３の圧縮比は２．５程度までなので、上記比較例では、上記単一のサーモコンプレッサ３００に既存のサーモコンプレッサ３が採用不可能となる。

In each of the thermocompressors 3 of the example and the comparative example, the steam sucked from the storage chamber 8 of the 9th stage 2I is changed from 12.34 [KPa] (9th stage 2I) to 51.33 [KPa] (frontmost stage). 2A) is required to be boosted. In the embodiment, as shown in FIG. 4, the required boost ΔP is shared by the two thermocompressors 3 (the suction thermocompressor 3A and the supply thermocompressor 3Z). Specifically, the pressure is increased from 12.34 [KPa] (9th stage 2I) to, for example, 26.15 [KPa] by the suction thermocompressor 3A, and the steam is increased by 26.15 [KPa] by the supply thermocompressor 3Z. To 51.33 [KPa] (first stage 2A). In this case, the compression ratio of the suction thermocompressor 3A (the pressure of the supplied steam with respect to the pressure of the sucked steam) is 2.12, and the compression ratio of the supply thermocompressor 3Z is 1.96. Since the compression ratio of the existing thermocompressor 3 is up to about 2.5, in the above embodiment, the existing thermocompressor 3 can be used for both the suction thermocompressor 3A and the supply thermocompressor 3Z. On the other hand, in the comparative example, as shown in FIG. 5, since it is configured by a single thermocompressor 300, the required boost ΔP is not shared by a plurality of thermocompressors 3. Specifically, the pressure of the steam is increased from 12.34 [KPa] (9th stage 2I) to 51.33 [KPa] (first stage 2A) by a single thermocompressor 300. In this case, the compression ratio of the single thermocompressor 300 is 4.16. Since the compression ratio of the existing thermocompressor 3 is up to about 2.5, in the comparative example, the existing thermocompressor 3 cannot be used for the single thermocompressor 300.

  As described above, according to the multi-effect fresh water generator 1 according to Embodiment 1 of the present invention, the existing thermocompressor 3 can be employed to increase the pressure of the vapor in the subsequent evaporator 2, so that the configuration is simple. Can improve performance.

[Embodiment 2]
A multi-effect fresh water generator 1 according to Embodiment 2 of the present invention is a multi-effect fresh water generator 1 according to Embodiment 1 described above, wherein a plurality of thermocompressors 3 are replaced with three thermocompressors 3. .

In the following, the description will be made by paying attention to portions different from those of the first embodiment, and the same components as those of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.
As shown in FIG. 6, the plurality of thermocompressors 3 in the multi-effect fresh water generator 1 according to Embodiment 2 of the present invention includes an intermediate thermocompressor 3B in addition to the suction thermocompressor 3A and the supply thermocompressor 3Z. . The intermediate thermocompressor 3B sucks and raises the pressure of the steam boosted by the suction thermocompressor 3A, and then sucks the steam to the supply thermocompressor 3Z. The diffuser 36 of the suction thermocompressor 3A and the suction part 31 of the intermediate thermocompressor 3B are connected by the first steam relay pipe 20A, and the diffuser 36 of the intermediate thermocompressor 3B and the suction part 31 of the supply thermocompressor 3Z are connected by the second steam relay. Connected by a tube 20B.

  In the multi-effect fresh water generator 1 according to Embodiment 2 of the present invention, the required boost ΔP is shared by the three thermocompressors 3A, 3B, and 3Z, so that they are shared by the two thermocompressors 3A and 3Z. Compared to the case, the pressure increase required for each thermocompressor 3 is further reduced. For this reason, the existing thermocompressor 3 having a smaller compression ratio can be employed. Further, as shown in FIG. 7, it is possible to increase the pressure of the vapor of the evaporator 2 at a later stage (for example, the last stage 2Z) by adopting the existing thermocompressor 3.

  Thus, according to the multi-effect fresh water generator 1 according to Embodiment 2 of the present invention, the existing thermocompressor 3 having a small compression ratio can be used to increase the pressure of the vapor in the further-stage evaporator 2. Therefore, the performance can be further improved with a simple configuration.

  In the second embodiment, the plurality of thermocompressors 3 are described as three thermocompressors 3, but may be four or more. In this case, a plurality of intermediate thermocompressors 3B are connected in multiple stages.

DESCRIPTION OF SYMBOLS 1 Multi-effect type fresh water generator 2 Evaporator 3 Thermocompressor 3A Suction thermocompressor 3B Intermediate thermocompressor 3Z Supply thermocompressor 5 Heat transfer pipe 8 Storage chamber 9 Drive steam supply part 18 Steam suction pipe 19 Steam supply pipe 20 Steam relay pipe 20A 1st One steam relay pipe 20B Second steam relay pipe 31 Suction part 32 Drive part 33 Nozzle part 34 Body 35 Sleeve 36 Diffuser

Claims (3)

A multi-effect fresh water generator comprising an evaporator arranged in a plurality of stages and a plurality of thermocompressors,
The evaporator is configured to evaporate raw water from outside and obtain pure water by cooling and condensing steam.
The plurality of thermocompressors sucks and boosts the vapor of the evaporators in the second and subsequent stages, and further evaporates after boosting the steam boosted by the suction thermocompressors, A multi-effect fresh water generator characterized by having a supply thermocompressor for supplying to the water.   The plurality of thermo-compressors are three or more thermo-compressors, and have an intermediate thermo-compressor that sucks and pressurizes the steam boosted by the suction thermo-compressor and then sucks the steam into the supply thermo-compressor. Item 2. The multi-effect fresh water generator according to Item 1. The multi-effect fresh water generator according to claim 1 or 2, further comprising a driving steam source connected to all of the plurality of thermocompressors to supply driving steam for boosting.

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