JP4618432B2 - Multistage flash evaporative water freshener - Google Patents

Description

The present invention relates to a multi-stage flash evaporation type fresh water generator used for producing fresh water from seawater, for example.

  Many types of multistage flash distillation type fresh water generators have been proposed, but in each case, seawater, ie, brine, is introduced into the heat transfer tube of the condenser, and the water vapor generated by flash evaporation is cooled and condensed on the outer surface of the heat transfer tube. Production water is used (see Patent Documents 1 to 5).

  For example, as shown in FIG. 3, the brine passes through a plurality of condensers (A1)... (An) connected in series from the low temperature stage to the high temperature stage, and at that time, the temperature is increased by several degrees. The brine used as cooling water in the hottest stage condenser (An) exits the condenser (An) and is then heated in the heater (B) to the top brine temperature and then the hottest stage evaporation. It is introduced into the chamber (C1), flows down to the evaporation chamber (Cn) at the lowest temperature stage while being sequentially flushed under reduced pressure, and is discharged out of the apparatus. During this time, the water vapor generated by flash evaporation in each stage is cooled and condensed on the outer surface of the heat transfer tube and taken out as production fresh water.

  In the above prior art, a large-pump seawater pump (D) and a brine circulation pump (E) are required to allow brine to flow inside the condenser heat transfer tube with a large ratio of pipe length to pipe diameter and very high fluid friction resistance. However, the power consumption is very large, and in addition, there is a problem that a pump having a large flow rate and a high head is very large and expensive.

In recent years, multi-stage flash distillation type fresh water generators tend to be larger, and there is an urgent need to solve the problems of the prior art.
JP 2000-84302 A JP 2000-107501 A JP 2000-107502 A JP 2000-325944 A JP 2001-962 A

An object of the present invention is to overcome the above-described problems in the prior art and to provide a multistage flash distillation type fresh water generator with low power consumption at a low cost.

According to the first aspect of the present invention, a plurality of evaporation chambers (1) connected in series from a low temperature stage to a high temperature stage, and a pair of left and right condensers (3) provided above each evaporation chamber (1) ( 3 ′), and each condenser (3) (3 ′) includes a plurality of condensing heat transfer tubes (2) and a cooling brine spraying device provided so as to face these heat transfer tubes (2) from above. (4) In the multistage flash distillation type fresh water generator composed of the above, the evaporation brine flowing from the high temperature stage to the low temperature stage in the bottom of each evaporation chamber (1) is flashed under reduced pressure to generate water vapor. The water vapor is separated and removed by the brackish water separator (5), and then introduced into the condenser heat transfer tube (2). In each condenser (3) (3 ′), a cooling brine spraying device is installed at the top. (4) Cooling brine is sprayed toward the multiple heat transfer tubes (2) and flows down the outer surface of the heat transfer tubes. The water vapor passing through the pipe (2) is cooled to be condensed water, and the resulting production fresh water flows down to the production water receiver (10), from which it is taken out to the production water reservoir, where the remaining water vapor is not condensed. And non-condensable gas ascends the air passage (9) formed between the left and right condenser heat transfer tube groups in each stage and is discharged out of the system by the discharge device (7). The cooling brine sprayed toward (2) and heated while flowing down the outer surface of the pipe is collected in a cooling brine reservoir (6) provided under each condenser (3) (3 ′). Among adjacent stages, for cooling above the cooling brine reservoir (6) below the pair of low temperature stage condensers (3) (3 ') and above the pair of high temperature stage condensers (3) (3') The brine spraying device (4) is connected to the pumping device (8), and the cooling cooling brine in the low temperature stage is sprayed from the cooling brine spraying device in the high temperature stage, and the condensation in the high temperature stage. It is characterized in that it is used to cool the heat transfer tube.
The invention according to claim 2 is the multi-stage flash evaporation type fresh water generator according to claim 1, wherein in each stage, the plurality of condensation heat transfer tubes (2) constituting the left condenser (3) are arranged on the right side. The multiple condenser heat transfer tubes (2) constituting the right condenser (3´) are inclined downward toward the left side, and the right and left condensation heat transfer pipes (2) It is characterized by being inclined so as to descend toward the air passage (9) formed between the two.

According to the configuration of the present invention, by adopting the above configuration, the heat recovery can be efficiently performed, and the power consumption of the pump can be significantly reduced as compared with the prior art, thereby reducing the power consumption of the multistage flash. A distillation type fresh water generator can be provided at low cost.

  Hereinafter, a multistage flash evaporative fresh water generator according to an embodiment of the present invention will be described with reference to the drawings.

Example 1
In FIG. 1, a multistage flash distillation type fresh water generator has a plurality of evaporation chambers (1) connected in series from a low temperature stage to a high temperature stage (that is, from right to left), and above each evaporation chamber (1). It is mainly composed of a pair of left and right condensers (3) (3 ') provided. Each condenser (3) (3´) is composed of a plurality of horizontally-condensed heat transfer tubes (2) and a cooling brine spraying device (4) installed so as to face these heat transfer tubes (2) from above. And mainly consists of The cooling brine spraying device (4) is composed of, for example, a perforated plate, a spray nozzle, etc., and sprays the cooling brine uniformly over the plurality of condensation heat transfer tubes (2).

In the multistage flash distillation type fresh water generator having the above-described configuration, the evaporating brine flowing from the high temperature stage to the low temperature stage in the bottom of each evaporation chamber (1) is flashed under reduced pressure to generate water vapor. The generated water vapor is separated and removed by a brackish water separator (5) composed of a wire mesh, hook and vane, etc., and then introduced into the condenser heat transfer tube (2).

In each of the condensers (3) (3 '), cooling the brine from the cooling brine spraying device (4) is sprayed to a plurality of condensing heat transfer tubes (2) at the top, cooling flowing down the heat transfer tube outer surface In the brine, the water vapor passing through the condenser heat transfer tube (2) is cooled to become condensed water. The obtained production fresh water flows down to the production water receiver (10) and is taken out from here to the production water reservoir.

  The water vapor residue and non-condensable gas that are not condensed here ascend the vertical ventilation path (9) formed between the left and right condenser heat transfer tube groups in each stage, and discharge devices such as ejectors (7) Is discharged outside the system.

On the other hand, the cooling brine sprayed toward the condenser heat transfer tube (2) and heated while flowing down the outer surface of the tube is a cooling brine reservoir (3 ′) provided under each condenser (3) (3 ′). Collected in 6). Of the adjacent stages, a pair of condenser cold stage (3) (3 ') cooling the brine reservoir (6) and a pair of condenser hot stage under (3) for cooling the top of (3') brine spraying device and (4) are connected via a pumping device such as a pump (8), brine for flow down the cooling of the low temperature stage is sprayed from the cooling brine spraying apparatus of the hot stage, the high-temperature stage condenser Den Used for cooling of heat tubes.

With the above configuration, the present invention can realize a fresh water generator that is less expensive than the prior art. That is, the head of the pumping device is the sum of the head corresponding to the pressure difference between the evaporation chambers (1) of each stage and the height to the cooling brine spraying device (4), which is much higher than the conventional technology. A small head is enough. However, when a brine pump is arranged at each stage, the cost of the pump may be higher than that of the conventional technology, but a configuration in which a plurality of stages of cooling cooling brine are collectively supplied to a plurality of stages on the high temperature side. By doing so, the cost of the pump can be made smaller than that of the prior art. Further, in this case, the driving power is reduced as compared with the prior art.

  On the other hand, the amount of steel material in each part of the apparatus is greatly reduced as compared with the prior art. For example, in the case of the present invention, heat transfer by a thin coating is performed both outside and inside the tube, so that higher heat transfer characteristics can be obtained as compared with the prior art. It can be greatly reduced. In addition, since the pressure of the brine is extremely lower than that of the prior art, the thickness of the pressure resistant steel such as the tube sheet and the brine conduit can be greatly reduced.

Example 2
In this embodiment, as shown in FIG. 2, in each stage, the plurality of condensation heat transfer tubes (2) constituting the left condenser (3) are inclined slightly downward toward the right side, and the right condenser The plurality of condensation heat transfer tubes (2) constituting (3 ′) are inclined slightly downward toward the left side. That is, the left and right condensing heat transfer tubes (2) are inclined so as to descend slightly toward the vertical air passage (9) formed therebetween. Therefore, the production fresh water generated by the condensation of water vapor in the condenser heat transfer tube (2) easily flows down from the inclined lower end of each tube to the production water receiver (10). Other configurations of this embodiment are the same as those of the first embodiment.

Example 3
In this embodiment, in FIG. 1, a multistage flash distillation type fresh water generator is constituted from a plurality of condensing chambers (1) connected in series from right to left, that is, from a low temperature stage to a high temperature stage. Are also arranged in the front-rear direction. Other configurations of this embodiment are the same as those of the first embodiment.

It is a vertical longitudinal cross-sectional view which shows the structure of the multistage flash distillation type fresh water installation in Example 1. FIG. It is a vertical longitudinal cross-sectional view which shows the structure of the multistage flash distillation type fresh water mounting in Example 2. It is a flowchart of the multistage flash distillation type fresh water generator of a prior art.

(1) Evaporation chamber
(2) Condensation heat transfer tube
(3) (3´) Condenser
(4) Brine spraying device for cooling
(5) Brackish water separator
(6) Cooling brine reservoir
(7) Discharge device
(8) Pumping equipment
(9) Ventilation path
(10) Production water receiving

Claims (2)

A plurality of evaporation chambers (1) connected in series from the low temperature stage to the high temperature stage, and a pair of left and right condensers (3) (3 ′) provided above each evaporation chamber (1), Each condenser (3) (3 ') is composed of a plurality of condensing heat transfer tubes (2) and a cooling brine spraying device (4) provided so as to face these heat transfer tubes (2) from above. In the multistage flash distillation type fresh water generator, the evaporating brine flowing from the high temperature stage toward the low temperature stage in the bottom of each evaporation chamber (1) is flashed under reduced pressure to generate water vapor. ), After separating and removing the liquid, it was introduced inside the condenser heat transfer tube (2), and in each condenser (3) (3 ′), cooling brine was fed from the cooling brine spraying device (4) at the top. A cooling brine sprayed to the multiple heat transfer tubes (2) and flowing down the outer surface of the heat transfer tubes, and water vapor passing through the condenser heat transfer tubes (2). The product fresh water obtained flows down to the production water receiver (10) and is taken out from this into the production water reservoir, where the water vapor residue and non-condensable gas that are not condensed here The air flow path (9) formed between the left and right condenser heat transfer tube groups is ascended and discharged from the system by the discharge device (7), while being scattered toward the condenser heat transfer tube (2). The cooling brine heated while flowing down the outer surface of the tube is collected in a cooling brine reservoir (6) provided under each condenser (3) (3 ′). The cooling brine reservoir (6) below the pair of condensers (3) (3´) and the cooling brine spraying device (4) above the pair of high-temperature stage condensers (3) (3´) are pumped up. The cooling brine in the low-temperature stage is sprayed from the brine spraying device in the high-temperature stage and used to cool the condensation heat transfer tubes in the high-temperature stage. Characterized Rukoto, multistage flash evaporation type fresh water generator. In each stage, the plurality of condensation heat transfer tubes (2) constituting the left condenser (3) are inclined downward toward the right side, and the plurality of condensation heat transfer tubes (3 ′) constituting the right condenser (3 ′) ( 2) is inclined downward toward the left side, and the right and left condensing heat transfer tubes (2) are inclined downward toward the air passage (9) formed between them. The multi-stage flash evaporation type fresh water generator according to claim 1.

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