DE1095699B - Evaporator for a sea water distillation plant - Google Patents

Description

The invention relates to an evaporator for an evaporator that operates with a continuous supply of seawater Sea water distillation plant with a substantially vertical, through one or more horizontal ones Transverse walls in a boiling chamber below and one or more above this or one above the other Separation chambers divided housing, in which the boiling chamber is a centrally located Contains heat exchanger device for evaporating the sea water and with a central and above this arranged line for discharging the generated steam and the entrained by this Seawater into the separation chamber located above the boiling chamber and with an inlet opening for Lake water is provided near their bottom.

An evaporator for producing drinking water has already become known, which is located in the lower part of a The boiler has a cylindrical shape, with a large one. Number of heat exchangers provided with radial fins having. The sea water is fed in the middle of the boiler and is kept constant by a float Height held.

In previously known sea water evaporators, the sea water of the boiling chamber is taken from a sea water storage tank, which is arranged above the boiling chamber, via a standpipe that the boiling chamber interspersed, fed. To maintain a constant seawater level in this reservoir, a float operated inlet valve has heretofore been used.

This working with float control evaporator systems have the disadvantage that the float or control mechanism as a result of deposits of contaminants in the feed water can jam.

The object of the invention is therefore to provide an evaporator to create, in addition to a higher degree of efficiency, a largely automatic control of the Evaporation process causes without the aid of float devices.

This is achieved according to the invention that between the wall of the boiling chamber and the Heat exchanger around this with a constant distance to both an essentially vertical one Jacket is provided, the one between it and the heat exchanger forming, ascending Column of boiling seawater and steam limited, the jacket being designed as an overflow and so high is that part of the water of the column flows back over its upper edge into the boiling chamber while the remaining water from the steam through the connecting line to the separation chamber above is discharged.

Another essential feature of the invention vaporizer
for a sea water distillation plant

Applicant:

Emhart Manufacturing Company,
Hartford, Conn. (V. St. A.)

Representative:

Dr.-Ing. K. Boehmert and Dipl.-Ing. A. Boehmert,
Patent Attorneys, Bremen 1, Feldstr. 24

Claimed priority:
V. St. v. America 6 February 1956

William Rodger Williamson,
Wethersfield, Conn. (V. St. Α.),
has been named as the inventor

consists in that the transverse wall separating the boiling chamber and separation chamber is designed so that they have an annular and in cross-section V-shaped, drainable sump around the outlet line from the Boiling chamber forms in which part of the seawater contained in the steam-water mixture discharged through the pipe collects. Here is the training is preferably such that the side facing the boiling chamber of the transverse wall with its annular profile is arranged to the upper edge of the jacket that it is for the rising in the jacket Steam-water column forms both a baffle plate and a guide device, which separates the part of the water from the rising water-steam column that has overflowed via the jacket supports and leads steam and entrained water into the outlet pipe.

This new arrangement according to the invention gives the following advantages:

a) There is a largely automatic regulation of the evaporation process without the use achieved by float systems.

h) The excess seawater supplied to the boiling chamber is continuously generated by the Steam discharged from the boiling chamber.

c) A constant water level is maintained in the boiling chamber.

d) The arrangement of the jacket a better heat transfer is achieved because by means of

009 679/60

the heating fins of the heat exchanger are wetted in their entire length and the circulation of the sea water after leaving these heating fins in the boiling chamber will.

Further advantages of the invention emerge from the following description in connection with FIG Drawing in which a preferred embodiment is explained, for example. It shows

Fig. 1 is a schematic view of an evaporator for a seawater distillation plant and

Fig. 2 is a horizontal cross section through the boiling chamber of the evaporator along the line 2-2 of the Fig. 1.

The evaporator 10 consists of a cylindrical housing 12 which, from bottom to top, is divided into three chambers 14, 16 and 18 is divided. The lower chamber 14 forms a closed boiling chamber in which the sea water is heated and evaporated; this chamber is from the first separation chamber 16 separated by a horizontal partition 20. The first separation chamber 16 consists of a centrifugal separation chamber, in which water and foam are separated from the steam produced when the seawater is boiled. It is also through a bulkhead 22 separated from the upper or second separation chamber 18. This is the final one Separation of the water from the vapor before the vapor generated by boiling the sea water is discharged from the evaporator 10 to a condenser (not shown).

The present invention does not relate to the method or to devices known per se for separating water and steam.

In the boiling chamber 14 shown in FIGS. 1 and 2 there is a heat exchanger 26, which is designed as a bell heat exchanger according to US Pat. No. 2,649,408. This consists in essentially of a generally cylindrical metal housing with deep corrugations or heating fins 28. This is closed at the top by a plate or a head piece 30 and its bottom 32 opens into its central part in a cylindrical pot 34 which extends vertically downwards through the bottom of the Evaporator housing 12 is performed. A heating steam supply pipe 36 leads vertically through this pot 34 upwards into the heat exchanger 26.

The sea water is introduced into the boiling chamber 14 through an opening 38 and reaches a water level L therein. This can be changed, as follows from the following. The seawater in the boiling chamber 14 is heated because it touches the outer surfaces of the heat exchanger 26 between the corrugations or heating fins 28 and thus absorbs heat from the heating steam supplied, which enters through the line 36 and in the heat exchanger 26 within the hollow fins or corrugations 28 circulates. As a result of the heat being given off to the surrounding seawater, the steam condenses in the heat exchanger 26 and its condensate runs off into the pot 34; from here it can be discharged via a line 40 and a pump 41 to the boiler in which the heating steam was generated. The part of the steam which is already condensing in the steam supply line 36 is discharged through the opening 42 into the pot 34.

According to the invention, one is essentially vertical and cylindrical and more open at both ends Jacket 44, the height of which corresponds essentially to that of the heat exchanger 26, in the boiling chamber 14 arranged around the heat exchanger. The jacket 44 faces from the outer edges of the heating fins 28 the heat exchanger at a distance.

The inner surface of the jacket 44 and the outer surfaces of the heating fins 28 of the heat exchanger 26 form an annulus with a vertical axis in which a mixture of boiling seawater, foam and steam is formed. Because this mix Contains foam and steam in addition to seawater, its specific density is lower than that of seawater on the outside of the jacket 44, since neither foam nor steam is formed there. Consequently causes the specifically heavier water on the outside of the jacket 44 a rapid increase in the specifically lighter mixture in the annulus between the heating fins and the jacket 44, and a faster rise of the mixture causes the entire surface of the finned heat exchanger enveloped by the rising column of water, foam and steam.

The violent boiling between the heating fins 28 and the high rate of rise of the column within of the shell 44 carries a substantial amount of water and foam up with the steam. As will be explained in detail later, it is desirable to carry foam and some water with the steam, when this is discharged from the boiling chamber 14; however, not all of the Water flowing out of the coat will be carried away. A certain amount already occurs within the boiling chamber 14 Separation of steam and water before the steam is removed from this and the first separation chamber 16 is fed.

Since, according to the invention, the jacket 44 is also arranged at a distance from the housing 12, this does not work upwardly entrained water from the water column within this mantle over its upper edge outside and flows back to the seawater column surrounding the jacket in the boiling chamber 14.

In order to facilitate this overflow, the lower one facing the boiling chamber 14 is according to the invention .Side of the transverse wall 20 with its annular profile so arranged to the upper edge of the shell 44, that they have both a baffle plate and a baffle plate for the steam-water column rising in the jacket Forming guiding device, which separates the then flowing over the jacket part of the water from the supports rising steam-water column and leads steam and entrained water into the outlet opening of line 46.

According to the invention, the transverse wall separating the boiling chamber 14 and the separation chamber 16, ie the intermediate floor 20, can be designed so that it forms an annular sump S , which is V-shaped in cross section and can be emptied, around the outlet opening of the line 46 from the boiling chamber, in which some of the seawater contained in the steam-water mixture discharged through line 46 collects.

The steam, the entrained foam and the water are discharged from the sump S via a line 46 from the boiling chamber 14. The outlet opening of the line 46 lies in the middle of the partition wall 20 within the annular trough which forms the sump S. The line 46 leads essentially horizontally above the partition 20 as the bottom of the first separation chamber 16 through the housing 12 to the outside of the housing, then upwards and then with a tangential inlet 48 back into the upper part of the separation chamber 16.

The water that collects in the sump S and is heavily enriched with salt and other impurities contained in the seawater is discharged from the sump S via one or more lines 62 leading radially outward.

Furthermore, there is at least one vertical standpipe 68 which has a relatively small diameter and through the partition 20 between the boiling chamber 14 and the first separation chamber 16 performs. This tube 68 does not serve as a line between the two chambers for filling the Boiler, but as a compensation line or compensation pipe between them. It runs from the lower part the boiling chamber 14 through the partition 20 and extends slightly beyond that, so that less brine of the first separation chamber can run back into the boiling chamber. Its lower end plunges into that Water of the boiling chamber 14 a. With this compensating pipe 68 a device is to be created, with which more water can be quickly removed from the boiling chamber 14 than it is due to the entrainment is possible with the steam. This is particularly important when starting up the system and adjusting the working conditions important if sudden and relatively high pressure increases in the boiling chamber appear. Water then flows up through line 68 into the first separation chamber and becomes via line 62 removed. However, under normal conditions, no water will flow through the pipe 68. A sudden increase in the amount of steam entering the heat exchanger can especially occur in cause a high water level in the boiling chamber 14 a flow through line 68 until the water level has dropped again sufficiently. Usually, dragging through the line is enough 46 to maintain a constant water level in the boiling chamber.

The operation of the evaporator for a distillation plant shown in FIG. 1 will now be described below. When the system is started up, seawater is pumped into the boiling chamber 14 of the evaporator until the seawater in the boiling chamber reaches approximately the water level marked L. The steam introduced into the heat exchanger 26 then begins to heat the seawater within the shell 44.

The steam generated in the boiling chamber is discharged from this via line 46 and, as described, entrains foam and some seawater. Foam and water in the steam are separated from the steam in the first and second separation chambers, and the dry steam is supplied from the evaporator 10 to a condenser. The concentrated salt water, the brine, separated from the steam-water mixture in the evaporator, runs off into the annular sump S and is discharged to the outboard.

When the seawater flow rate is set to its correct value, there is no further regulation necessary while the system is running. This results in a regulation that runs essentially automatically is achieved in which a substantially constant evaporation is maintained and fluctuations can be balanced in the seawater supply without reducing the amount of distillate formation will be changed.

This essentially constant distillate recovery without the need to regulate the seawater flow rate if there are any changes to the same, the heat exchanger jacket caused and improved by the annular partition above the boiling chamber, the evaporator an amount of distillate is generated which essentially only by changing the steam supply to the heat exchanger of the boiling chamber is affected. This arrangement and formation of the coat and partition also enable a substantially constant level of sea water in the boiling chamber is maintained for a given seawater supply, d. that is, the vaporizer has a change compensates in the sea water supply by setting a new sea water level in the boiling chamber, without causing a change in the amount of distillate.

There, as already mentioned, the heat exchanger surfaces of the heat exchanger regardless of the seawater level outside the jacket are circulated is a significant change in the generation of vapor and the amount of distillate only by changing the steam supply to the heat exchanger, as described in more detail below will.

The way in which the jacket and the separating or guiding surface arranged above it the seawater level regulating in the boiling chamber with a given amount of supplied seawater is best can be explained if one considers the occurrence of a change in the amount of supplied seawater and Considered the constant amount of steam supplied to the heat exchanger. As already mentioned, With a constant supply of heating steam and sea water, the sea water level in the boiling chamber is stabilized, constant evaporation takes place, water being carried along with the steam in a constant amount is and also overflows in a constant amount over the jacket or flows back into the boiling chamber. If the amount of supplied seawater increases, the water level on the outside rises of the coat. This results in an increased entrainment of the water because it is now the outside of the jacket 44 is more water, which the water-steam column between the heat exchanger 26 and the jacket 44 can rise faster because it is specifically heavier than that Water-steam mixture inside the jacket. The water level continues to rise until it intensifies Being carried away by the steam compensates for the excess supply of seawater and thus the water level is stabilized in a higher position. The amount of vapor generated remains essentially unchanged.

If the amount of supplied seawater decreases, the seawater level in the boiling chamber falls, and there are now smaller amounts of water with a lower density on the upper inner part of the coat. But if there is less water here, the entrainment also decreases, and the The amount of water overflowing and circulating around the wall of the jacket is reduced. Of the Water level in the boiling chamber continues to drop until the reduction in entrainment reduces the seawater supply compensates. The amount of vapor generated remains essentially unchanged.

If the amount of sea water supplied is constant and, on the other hand, the heating steam supply to the heat exchanger is decreased, there is less vigorous boiling first and thus a decrease in entrainment. The water level rises, causing the water content of greater density at the upper inner Part of the mantle is enlarged, which in turn increases the entrainment. The water level

continues to rise until the increasing entrainment causes the water level to stabilize. The stabilization at this moment it is similar to the one with a constant supply of heating steam and an increasing supply of seawater occurs, but here the amount of distillate formation increases to a new constant Water level from.

If the seawater supply remains constant and the heating steam supply increases, a more violent one occurs first Simmer, which causes a stronger entrainment. This increased entrainment reduces the Height of the sea water level so that the content of denser water at the top of the mantle is reduced which in turn reduces the entrainment. This reduction in entrainment stabilizes the water level and is similar to the stabilization that occurs with a constant supply of heating steam and a lower supply of seawater; however, the size of the Distillate formation up to a new, essentially constant water level.

This results in the advantageous effect of the jacket and the ring-shaped ones arranged above it Partition or guide wall according to the invention.

While the inventive improved evaporator in connection with a single distillation, -tionsanlage has been described, understandably several such evaporators in series can be switched to create a multiple evaporator. With such low-pressure multiple evaporator systems or systems, such a largely automatic control is particularly advantageous.

Claims (3)

Claims = 1. Evaporator for a sea water distillation system that works with a continuous supply of sea water with an essentially vertical, through one or more horizontal transverse walls into a boiling chamber below and one or more housings subdivided above this or one above the other, in which the boiling chamber has a centrally located heat exchanger device for evaporation of the lake water and with a centrally and above this arranged line to Discharge of the generated steam and the sea water entrained by it into the above Separation chamber lying on the boiling chamber and with an inlet opening for sea water nearby its bottom is provided, characterized in that with a constant distance to both between the wall of the boiling chamber (14) and the heat exchanger (26) around this substantially vertical jacket (44) is provided, the one between it and the heat exchanger forming, rising column of boiling seawater and steam bounded, with the mantle (44) is designed as an overflow and so high that part of the water of the column over its upper Edge flows back into the boiling chamber (14), while the remaining water flows through from the steam the connecting line (46) to the overlying separation chamber (16) is discharged. 2. Apparatus according to claim 1, characterized in that the transverse wall (20) separating the boiling chamber (14) and separating chamber (16) is designed so that it has an annular, V-shaped cross-section and drainable sump (S) around the outlet opening the line (46) from the boiling chamber, in which part of the seawater contained in the steam-water mixture discharged through the line (46) collects. 3. Apparatus according to claim 2, characterized in that the boiling chamber (14) facing Side of the transverse wall (20) with its annular profile so to the upper edge of the shell (44) is arranged that they have both one for the rising steam-water column in the jacket The baffle plate as well as a guide device forms the separation of the overflow over the jacket Part of the water from the rising steam-water column supports and steam and entrained water into the outlet opening the line (46) leads. Considered publications:
German Patent Nos. 881 195, 963 843;
U.S. Patent No. 2,649,408. 1 sheet of drawings © 009 679/60 12.