JP5388799B2 - Multi-stage flash water generator - Google Patents

Description

  The present invention relates to a multistage flash type fresh water generator.

  In a multistage flash type fresh water generator, a plurality of evaporation chambers are formed in multiple stages (in series) in an evaporation container, and in each of these evaporation chambers, flash evaporation of seawater (hereinafter also referred to as brine) ( Evaporation under reduced pressure is performed and the vapor evaporated in each evaporation chamber is cooled to obtain fresh water from seawater.

  That is, in the multi-stage flash type fresh water generator, a plurality of evaporation chambers are sequentially arranged in multi-stages by partition walls provided at predetermined intervals in the evaporation container, and each of the evaporation chambers contains brine. Heat exchange means for obtaining fresh water by introducing and cooling the steam (water vapor) obtained by flash evaporation is arranged, and an opening for moving brine is formed in the lower part of the partition wall. ing.

  By the way, although the flow rate of the brine also changes according to the fresh water generation load, at this time, the height of the opening that communicates between the evaporation chambers is also an appropriate height, for example, at least no blow-through occurs. It is necessary to maintain the height, and when the liquid level of the brine is high, the brine flowing through the bottom of the evaporation chamber is difficult to evaporate (because the static pressure increases), and the evaporation performance is reduced. It means that.

  For this reason, in order to set the liquid level height on the brine side to an appropriate value, a movable weir capable of adjusting the opening height is provided in the opening (for example, see Patent Document 1).

JP 2008-136923 A

  However, as described above, it is very troublesome to provide a movable weir at the opening provided in the partition wall for partitioning the evaporation chamber and adjust the opening height according to the liquid level of the brine. In addition, at the time of the adjustment, it is necessary to stop the operation of the fresh water generator, which causes a problem that the operation efficiency is lowered.

  Therefore, when the height of the brine changes, the present invention can maintain the height of the brine optimally without adjusting the height of the opening, that is, without stopping the operation of the fresh water generator. An object of the present invention is to provide a multistage flash type fresh water generator.

In order to solve the above-mentioned problem, the multistage flash type water freshener according to claim 1 of the present invention has seawater evaporation chambers formed in multiple stages in the container body via the partition walls and formed below the partition walls. In the multi-stage flash type fresh water generator in which heat exchange means for guiding and cooling the flash evaporated steam is arranged at the upper part of each evaporation chamber formed by communicating the upstream evaporation chamber and the downstream evaporation chamber through the opened opening. ,
A cylindrical body in which a plurality of discharge holes are formed is attached to the upper edge of the opening of each partition wall, and low temperature seawater lower than the temperature of the seawater in the upstream evaporation chamber is supplied to each cylindrical body. Connect a low-temperature fluid supply pipe and a high-temperature fluid supply pipe that supplies high-temperature seawater that is higher than the temperature of seawater in the upstream evaporation chamber,
A level gauge for detecting the level of seawater in each of the evaporation chambers is provided, and the measurement height from each level gauge is input to be connected to the cylindrical body of the partition wall on the downstream side of each evaporation chamber. A control means for controlling the on-off valve provided in each of the supply pipes;
When the measured height is higher than the set height, the control means opens the on-off valve provided in the low-temperature fluid supply pipe, and when the measured height is lower than the set height, the high-temperature fluid supply pipe is opened. The on-off valve provided in is opened .

  Moreover, the multistage flash-type fresh water generator according to claim 2 is configured such that the installation range of the discharge hole in the cross section of the tubular body in the fresh water generator according to claim 1 is an upstream horizontal line and a lower vertical line. The range is 90 degrees between.

Furthermore, the multistage flash-type fresh water generator according to claim 3 uses steam instead of the high-temperature seawater in the fresh water generator according to claim 1 or 2.

  According to the configuration of the multistage flash type fresh water generator, since the cylindrical body is arranged at the upper edge of the opening of the partition wall, the pressure loss is reduced compared to the case where the cylindrical body is not provided. The evaporation of seawater, that is, brine in the head is suppressed, and when the liquid level rises due to the static pressure decreasing and evaporating in front of the opening, the brine is blown into the opening to lower the saturation pressure. Thus, the evaporation of the brine is suppressed, so that the rise of the brine liquid level on the upstream side can be suppressed, and therefore the evaporation of the brine in the evaporation chamber on the upstream side can be promoted. A decrease can be prevented.

  In addition, when the brine in the evaporation chamber is too low and blow-through occurs in the opening, high temperature brine or steam is blown into the opening to promote the evaporation of the brine, so the pressure loss at the opening Becomes larger and the static pressure increases, so that blow-through at the opening can be prevented.

  That is, when the height of the brine changes, the height of the brine can be optimally maintained without adjusting the height of the opening, that is, without stopping the operation of the fresh water generator.

It is a schematic sectional drawing of the multistage flash type fresh water generator concerning the Example of this invention. It is principal part sectional drawing of the evaporation chamber of the multistage flash | flush type fresh water generator. It is a principal part view for a comparison for demonstrating the effect | action of the cylindrical body of the evaporation chamber. It is principal part sectional drawing explaining the other effect | action by the cylindrical body of the evaporation chamber.

Hereinafter, the multistage flash type fresh water generator according to the embodiment of the present invention will be described based on specific examples.
First, the schematic structure of this multistage flash type fresh water generator will be described with reference to FIG.

  The multi-stage flash type fresh water generator includes a heater 1 that guides seawater and heats it with steam, and an evaporation container (also referred to as an evaporator) that guides high-temperature seawater heated by the heater 1 and performs flash evaporation. 2, a vacuum device 3 for sucking the air in the evaporation container 2 to a predetermined pressure or less, and a piping system (described later) for transferring seawater and the like.

  The container body 2a of the evaporation container 2 has a box shape having a predetermined length and a rectangular cross-sectional shape, and a plurality of partition walls 11 provided at predetermined intervals are provided inside the container body 2a. The evaporation chambers 12 are sequentially arranged in multiple stages (in series), and in each of the evaporation chambers 12, steam (water vapor) obtained by flash evaporation (vacuum evaporation) of seawater (hereinafter also referred to as brine) a. ) Cooling heat transfer tube (hereinafter referred to as heat transfer tube) 13 as a heat exchange means (also referred to as a heat exchange portion) for obtaining fresh water by guiding b and cooling, and a tray (receiving portion) for receiving fresh water at a position below it 14 is disposed, and the mist of the steam b is removed in the middle of the steam introduction passage 15 provided on the lower side of the heat transfer pipe 13 of each evaporation chamber 12 (downstream side in the seawater flow path direction) ( Demister to capture) 6 is provided. In addition, the pressure of each evaporation chamber 12 is made to become low sequentially from the heater 1 side with the vacuum apparatus 3, for example, the saturation temperature difference between adjacent evaporation chambers 12 is 3-4 degreeC. .

  As shown in FIG. 2, the upstream evaporating chamber 12 (12U) and the downstream evaporating chamber 12 (12D) communicate with each other at the lower part of each partition wall 11 to guide the brine a from the upstream side to the downstream side. 11a (also referred to as a communication opening) is provided.

  In FIG. 1, for ease of understanding, the case where three evaporation chambers 12 are provided in the container body 2a is shown, but in reality, the evaporation chambers 12 are arranged with 10 or more stages. In addition, two evaporation containers 2 themselves are arranged (in two stages). More specifically, an evaporation container as a heat recovery unit that recovers heat by heating the seawater supplied to the heater 1, and seawater (brine) discharged from the evaporation container as the heat recovery unit. An evaporation container serving as a heat release part that cools and releases heat to the outside is provided. In this embodiment, an evaporation container as a heat recovery part will be described.

Next, the piping system in this fresh water generator will be described.
A seawater supply pipe (cooling low-temperature seawater supply pipe) that is connected in series to the heat transfer pipes 13 arranged in the respective evaporation chambers 12 of the evaporation container 2 of the fresh water generator and guides the seawater for cooling (low-temperature seawater). ) 21, the first seawater transfer pipe 22 that guides the seawater from the heat transfer pipe 13 (13 </ b> A) disposed in the first stage evaporation chamber 12 (12 </ b> A) to the heater 1, and the heater 1 A second seawater transfer pipe 23 for transferring the heated high-temperature seawater to the first stage evaporation chamber 12 (12A) of the evaporation container 1, and a fresh water discharge pipe 24 for taking out fresh water collected in the tray 14 in each of the evaporation chambers 12, A third seawater transfer pipe 25 is provided for transferring the brine a in the final stage evaporation chamber 12 (12L) to the evaporation container of the heat release unit. Note that the steam supplied to the heater 1 is discharged as condensate drain.

Here, the overall flow will be briefly described.
In the above configuration, while the steam is supplied to the heater 1 and the inside of each evaporation chamber 12 is maintained at a predetermined pressure (negative pressure) by the vacuum device 3, the evaporation container 2 is supplied from the seawater supply pipe 21. The low-temperature seawater (seawater temperature is about 35 ° C., but is heated to about 43 ° C. through the heat release part) is sequentially passed through the heat transfer tubes 13 in the respective evaporation chambers 12. It is transferred into the heater 1 where it is heated to a predetermined temperature (for example, about 105 ° C.) by steam. Although not shown, actually, as described above, the seawater passes through the evaporation container as the heat release part and is heated to some extent, and then the evaporation container as the heat recovery part. 1 to be supplied.

  The heated high-temperature seawater, that is, the brine a is transferred into the first stage evaporation chamber 12 (12A) and subjected to flash evaporation under reduced pressure. This steam is cooled by the low-temperature seawater flowing in the heat transfer tube 13. It condenses into fresh water and falls onto the fresh water tray 14.

  Similarly, the brine that has entered the next-stage evaporation chamber 12 through the opening 11 a is also flash-evaporated and condensed by the low-temperature seawater that passes through the heat transfer tube 13 to become fresh water, and falls onto the tray 14. To do.

Thus, the high temperature seawater from the heater 1 is sequentially moved from the first stage evaporation chamber 12 (12A) to the last stage evaporation chamber 12 (12L).
In addition, in the evaporation container as the heat release unit, as in the evaporation container as the heat recovery unit, the low temperature flowing from the first stage evaporation chamber to the last stage evaporation chamber and flowing in the heat transfer tubes in the respective evaporation chambers. The fresh water is condensed by the seawater and falls on the fresh water tray. The fresh water obtained in both of these evaporation containers is finally taken out from the fresh water take-out pipe.

Although not shown, a pump for transferring each fluid is provided at least in the middle of the seawater supply pipe 21 and the predetermined transfer pipes 24 and 25.
As described above, the entire fresh water generator has been schematically described. Next, the configuration of the evaporation vessel, which is the gist of the present invention, in particular, the configuration of the partition wall, the increase in pressure loss at the opening, and the blow-off of seawater. A configuration capable of preventing the above will be described.

  In the evaporation container 1, as described above, a plurality of evaporation chambers 12 are sequentially formed by the partition wall 11 in the container body 2a, and an upstream evaporation chamber 12 (12U) is formed below the partition wall 11. And the downstream evaporation chamber 12 (12D) are provided with an opening (also referred to as a communication opening) 11a.

  And the cylindrical body (for example, the pipe is used) 31 is attached to the upper edge part of the opening part 11a of each partition wall 11 in the horizontal direction, and on the outer peripheral surface of this cylindrical body 31, A large number of holes, that is, discharge holes 31a are formed along the axial direction (horizontal direction).

  In addition, the formation range of the discharge hole 31a in the cross section (vertical plane) of the cylindrical body 31 is the 90 degree range on the upstream side and the lower part (that is, in the mathematical coordinate system, the third quadrant (180 Corresponding to ˜270 °).

  Furthermore, in this cylindrical body 31, the temperature of the low temperature seawater 3-4 degreeC lower than the temperature of the brine in the upstream evaporation chamber 12 formed of the partition wall 11 or 3-4 degreeC higher temperature The very high temperature seawater is configured to be supplied with low or very high temperature seawater according to the level of the seawater level in each evaporation chamber 12.

  That is, in order to supply the cylindrical body 31 with the cryogenic seawater supply pipe (cryogenic fluid supply pipe) 41 for supplying the cryogenic seawater that is 3 to 4 ° C. and the cryogenic seawater that is 3 to 4 ° C. higher. The high temperature seawater supply pipe (micro high temperature fluid supply pipe) 42 is connected, and in the middle of each of the supply pipes 41, 42, on-off valves 43, 44 are respectively provided, and in each evaporation chamber 12. A control means 33 for controlling the on-off valves 43 and 44 is provided by the liquid level gauge 32 arranged.

  As shown in FIG. 1, the control means 33 includes a liquid level setting unit 34 that can individually set the liquid level of the brine in each evaporation chamber 11, and a liquid level setting unit 34 that is set in each evaporation chamber 12. The measured height from the liquid level gauge 32 and the set height (set value) set by the liquid level height setting unit 34 are input and compared, and the measured height is higher than the set height (deep ), The on-off valve 43 provided in the micro-low temperature seawater supply pipe 41 is opened and closed. Conversely, when the measured height is lower (shallow) than the set height, the micro-high temperature seawater supply pipe 42 is provided. And a judgment control unit 35 for opening and closing the open / close valve 44. Specifically, the on-off valve 43 is opened when the measured height is higher than the set height, and the on-off valve 44 is opened when the measured height is lower than the set height.

  Thus, since the cylindrical body 31 is provided in the upper edge part of the opening part 11a of the partition wall 11, compared with the case where it does not provide, generation | occurrence | production of a contraction is prevented (that is, flow resistance is reduced). The flow pressure loss can be reduced, and therefore the brine flow can be smooth. Furthermore, since a very low temperature brine is discharged (spouted) from the cylindrical body 31 to the lower half part, the temperature is lowered, that is, the saturation temperature is lowered to suppress the evaporation of the brine. Can do. FIG. 3 shows a state in which flash evaporation occurs at the upper edge of the opening 11a, the static pressure increases, and the liquid level rises. FIG. 2 shows a case where a very low temperature brine is ejected from the discharge hole 31a of the cylindrical body 31 to suppress flash evaporation and the liquid level is lowered.

In the above configuration, the heated brine a is sequentially moved through the evaporation chambers 12 through the openings 11a provided in the lower part of the partition wall 11, and flash evaporation is performed.
Of course, when the brine a sequentially moves through the evaporation chamber 12, if the brine a moves from the upstream evaporation chamber 12U to the partition wall 11 of the evaporation chamber 12U, the presence of the cylindrical body 31 and the brine a from the discharge hole 31a. Due to the release, the pressure is reduced and flash evaporation is performed efficiently.

  That is, the brine a rapidly expands by flash evaporation, is led from the downstream steam introduction passage 15 to the heat transfer tube 13, and is cooled by the brine a having a low temperature to obtain fresh water. Of course, the mist of the brine a is removed by the demister 16.

  By the way, at this time, the cryogenic seawater is discharged from the discharge hole 31a of the cylindrical body 31 to the upstream side and downward, and the temperature of the brine a is lowered. That is, the saturation temperature is lowered, the evaporation on the upstream side of the opening portion 11a, that is, the orifice portion is suppressed, and the pressure is lowered. Furthermore, contraction is prevented by the cylindrical body 31 provided at the upper edge of the opening 11a, that is, pressure loss (flow resistance) is reduced, and an increase in the brine liquid level on the upstream side is suppressed. Therefore, a decrease in evaporation performance is prevented.

  On the other hand, when the liquid level of the brine a in the evaporation chamber 12 falls, the control means 33 detects that, and the opening / closing valve 44 of the very high temperature seawater supply pipe 42 is opened, so Is ejected from the cylindrical body 31 to the upstream side and downward.

  Thus, when very high temperature seawater that is about 3 to 4 ° C. is ejected, the temperature at the opening 11a rises as shown in FIG. 4, so that flash evaporation becomes active and pressure loss at the opening. And therefore the liquid level rises to prevent blow-through.

  According to said structure, since the cylindrical body was arrange | positioned at the upper edge part of the opening part of a partition wall, compared with the case where the cylindrical body is not provided, pressure loss (flow resistance) reduces and it is in an opening part. When the static pressure rises and the liquid level rises due to the evaporation of seawater, that is, brine, further evaporating before the opening, the brine is blown into the opening to lower the saturation pressure. Since the evaporation of the brine is suppressed, the rise of the brine liquid level on the upstream side is suppressed, and therefore the evaporation performance is prevented from being lowered.

  In addition, when the brine in the evaporation chamber has fallen too much and a blow-through has occurred in the opening, a very high temperature brine or steam is blown into the opening to promote the evaporation of the brine. Loss is increased and static pressure is increased, so that blow-through at the opening can be prevented.

  That is, when the height of the brine changes, the height of the brine is optimized without adjusting the height of the opening, that is, without stopping the operation of the fresh water generator (without reducing the operation efficiency). Can be maintained.

  By the way, in the said Example, in order to raise the liquid level of a brine, although very hot seawater was supplied to the cylindrical body, you may make it supply a vapor | steam instead.

DESCRIPTION OF SYMBOLS 1 Heater 2 Evaporation container 2a Container main body 3 Vacuum apparatus 11 Partition wall 11a Opening part 12 Evaporating chamber 13 Cooling heat transfer pipe 14 Receptacle 15 Steam introduction path 16 Demister 21 Seawater supply pipe 22 First seawater transfer pipe 23 Second seawater Transfer pipe 24 Fresh water take-out pipe 31 Tubular body 31a Discharge hole 32 Level gauge 33 Control means 34 Liquid level height setting part 35 Judgment control part 41 Cryogenic seawater supply pipe 42 Slightly hot seawater supply pipe 43 On-off valve 44 On-off valve

Claims (3)

Each evaporation chamber in which seawater evaporation chambers are formed in multiple stages in the container body via partition walls, and the upstream evaporation chamber and the downstream evaporation chamber are communicated with each other through an opening formed in the lower portion of each partition wall. In the multistage flash type fresh water generator in which heat exchange means for cooling the steam evaporated by flashing is disposed on the upper part of
A cylindrical body in which a plurality of discharge holes are formed is attached to the upper edge of the opening of each partition wall, and low temperature seawater lower than the temperature of the seawater in the upstream evaporation chamber is supplied to each cylindrical body. Connect a low-temperature fluid supply pipe and a high-temperature fluid supply pipe that supplies high-temperature seawater that is higher than the temperature of seawater in the upstream evaporation chamber,
A level gauge for detecting the level of seawater in each of the evaporation chambers is provided, and the measurement height from each level gauge is input to be connected to the cylindrical body of the partition wall on the downstream side of each evaporation chamber. A control means for controlling the on-off valve provided in each of the supply pipes;
When the measured height is higher than the set height, the control means opens the on-off valve provided in the low-temperature fluid supply pipe, and when the measured height is lower than the set height, the high-temperature fluid supply pipe is opened. A multi-stage flush type fresh water generator characterized by opening an on-off valve provided in the water.   The multi-stage flash type fresh water generator according to claim 1, wherein the installation range of the discharge hole in the cross section of the cylindrical body is a range of 90 degrees between the horizontal line on the upstream side and the vertical line on the lower side. .   The multistage flash type fresh water generator according to claim 1 or 2, wherein steam is used instead of high temperature seawater.

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