IL41459A - Vapour compressing distillation apparatus particularly for distilling sea water - Google Patents

Description

41459/2 VAPOUR COMPRESSING DISTILLATION APPARATUS, PARTICULARLY FOR DISTILLING SEA WATER »a ηΐ3Τ -my tnva:. .ηαν ρππ πρτ τρππ 41459/2 The present invention relates to an apparatus for the separation of solutes from solvents in solutions, more particularly the invention concerns vapour compressing distillation apparatus. The apparatus is especially-useful in sweetening sea water or brackish water.

In my Specification to Patent No. 31.373 I have described a method and an apparatus for sweetening sea water. It is the object of the present invention to produce an apparatus which may be built and which can be installed as a unit, meaning that most of the assembly can be attended to in the factory. The plant is made and the apparatus can be shipped to the site of use and set up there, there remaining only a minimal amount of work of assembly to be done on the spot.

In designing a plait of this kind, the following points have to be taken into consideration: in water sweetening processes, the incoming sea water to be sweetened has to be heated up, which is done by means of heat exchangers which commonly comprise a great number of metal tubes through which the incoming sea water flows. These metal tubes are rather expensive and in view of the great number to be installed, this item very much . increases the cost of the plant. Moreover, the tubes are Tather thick , walled and therefore the exchange of heat is not as efficient as is desirable.

A further point to be considered is the formation of scale which occurs in the heat transferring bodies or more particularly at the heat transferring side where the temperature of the sea water is rising. Thus where heat exchangers comprising tubes are used, as in known arrangements, the scale forms within the tubes.

The rate of evaporation of water is very low temperature and low pressure results in the formation of large volumes of vapour which in turn can be converted to a small volume of product, namely sweetened water.

According to the invention, the new compact apparatus comprises three operational superposed chambers or cells which are partitioned from one another and where in the intermediate one of them is provided a heat exchanger consisting of a plurality of vertically/ disposed hollow plate shaped allround closed members and extending radially in the chamber, the sea water travelling through the said chamber between the said plates, the top chamber housing a compressor, adapted to compress vapours anifi deliver them into the hollow plates, while the bottom chamber serves as condensate collecting space, and means for feeding solution into the middle chamber onto the heat exchanger plates, the said hollow plates having inlet spigots at top and like outlet spigots at bottom; an inlet into the casing - in its upper part - add an outlet from the bottom chamber being provided.

According to a further feature of the invention, the sea water is fed into the interior of the chamber comprising the hollow plates by means of multi-nozzle hollow ring which delivers a steady flow of sea water onto the heat-exchanger plates, the said nozzles being positioned 41459/-$ above and in line with the top faces of the plates. The sea water drips from the said multi-nozzled ring to the plates by gravity.

According to still another feature of the invention, the compressor which is provided in the top chamber is a steel blade disc ring double acting compressor.

The bottom chamber .which serves as accumulating station for the condensate is provided with a pump to remove the product from the said chamber.

According' to yet another feature, there is also provided an outlet for not condensable air and gases which are remnved by means of a vacuum pump or other conventional means · Incidentally the plant of the type referrred to just now is especially adapted for use in connection with electric power plants where sea water serves as the cooling medium and is available at the temperature of about 42°C, to enter the distillation plant and to be converted into sweet water. v The invention will now be described with reference to the annexed drawings. In the drawings Fig. 1 is a sche-matical elevational view of the new apparatus. Fig. 2 indicates the position of an identical apparatus being coupled with the first named one and being the next in a row of such distilling apparatus. Fig. 3 is a cross sectional view of the new a aratus on line III-III of Fi . 1 and Turning first to Fig. 1 there is provided an outer cylindrical casing which however may also be of prismatic shape and which is indicated by the numeral 1. This casing need not be designed for high pressures. Therefore no special requirements have to be considered in designing and making the casing. The interior of the casing is subdivided into three chambers by partitions extending in the horizontal, and numbered from top to bottom 2, 3 and 4.

Thus, by means of these partitions, there are created: a top chamber indicated by the numeral 5, middle zone chamber indicated by 6, narrow chamber 7 lying just beneath the chamber 6 and finally a bottom chamber 8.

Roughly speaking the top chamber 5 is intended for compression, the top and middle zone of chamber 6 contains the heat exchanger and the lower portion of chamber 6 serves as evaporation zone. The chamber 7 is a barrier or vapour trap (as will become evident) while the bottom chamber 8 serves for the collection of condensate ive. sweetened water.

The purpose and function of these chambers will become clear from the following. Turning first to the top central chamber indicated by the numeral 5, there is provided a compressor 18 by which vapours sucked from chamber 6 are compressed, transferring these downward, through spigots 11 toward a number of hollow plates 9 to which reference will be made presently. In the interior of chamber 6, there is provided a plurality of rectangularly shaped, hollow plates which are built of thin sheet metal, the individual plates being indicated by numeral 9» From the top and bottom faces of that plate there extend spigots leading into and out of the interior of the plates. The spigots 11 at top are composed of two parts inter-connected by connections 12· The division of spigots 11 into two parts and the connection by sleeves 12 facilitates the mounting and dismounting (if required) of the individual parts of the apparatus. Functionally, and for all practical purposes the two parts f®¾6m one spigot 11.

The spigots 11 are mounted on the partition walls extending between the chambers, so the upper spigot 11 depends from partition 2 while the lower spigot 11 is set in partition 3, Abwe the plates there is provided an annular pipe 13 provided with a great number of nozzles through which sea water conducted into the said ring can exit and flow down by gravity as a thin film over the' surfaces of the plates 9 and flow or drip through a zone 6a which constitutes the upper part of chamber 6 to be vapourised by contact with the hollow plates. The compressor 18 can suck these vapours through a chimney 19 from the zone 6a and deliver them from chamber 5 through the upper spigots 11 to the space in the interior of the plates 9. The suction exerted by the compressor reduces the pressure in the middle chamber 6. Sea water from which vapour had been extracted in zone 6a now fills the lower portion of chamber 6, indicated at 6b around the plates 9. Thus in the interior thereof the vapours are cooled and condensed. The condensate exits through the lower spigots 11 to enter the narrow chamber 7. An annular weir 7a disposed on partition 4 and extending into chamber 7 extends somewhat higher than the lower ends of the lower spigots 11. Thus the lower end of the lower spigots 11 preventing vapours from escaping from the interior of the plates. Water flowing from the outlet of the plates collects in the narrow space of chamber Ί- until its level -rises above the edge of the weir 7a to overflow into chamber 8 from which it can be drained.

The sea water in chamber 6 at 6b, now of higher salinity may be conducted to a successive indentical distillation apparatus ( Fig.2 ) through conduits 33, 35 where the same operation is repeated. Alternatively, the sea water of higher salinity in chamber 6 may be returned to the sea.

The water may be introduced directly fTom the sea or it may be preheated in a heater 37.

Claims (4)

WHAT IS CLAIMED IS : 41459/3

1. , An apparatus for the separation by distillation of solutes from solvents in solutions, comprising three operational superposed chambers or cells which are partitioned from one another and where in the intermediate one of them is provided a heat exchanger consisting of a plurality of vertically disposed hollow plate shaped allround closed members and extending radically in the chamber, the sea water travelling through the said chamber between the said plates, the top chamber housing a compressor adapted to compress a^d^ deliver them into the hollow plates, while the bottom chamber serves as condensate collecting space and means for feeding solution into the middle chamber onto the heat exchanger plates, the said hollow plates having inlet spigots at top and like outlet spigots at bottom, an inlet into the casing -in its upper part - and an outlet from the bottom chamber being provided,

2. An apparatus, as claimed in Claim 1, characterised by the provision - as means for feeding in the solution -of a multi-nozzle hollow ring arranged on top of the said hollow plates, the nozzles being in line, i.e. vertically above each plate, the said ring having an inlet port for the incoming solution.

3. · An apparatus, as claimed in Claim 1, characterised by the provision of a steel blade disc ring double acting compressor in the top of the apparatus.

4. An apparatus, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings ·