DE2135685C3 - Multi-stage flash evaporator - Google Patents

Description

The invention relates to a multi-stage flash evaporator with a vertical cylindrical, with pipe socket for supplying the desalination Salt water and housing provided for draining the non-evaporated salt water, inside it a condenser with jacket is arranged coaxially to the evaporation annulus, the openings / around Has flow of steam, distillate and non-condensable gases.

It is already a vaporizer with a multi-part Hüssigkcitsraum known (DT-AS 106b 541), where in arranged in the individual liquid chambers are. This known evaporator is used to evaporate solutions, the transition cross-sections of the not yet evaporated solution can be set between the individual liquid spaces.

The problem that is solved by the known evaporator is, with the same performance, the To reduce the surface of the pipes or to increase the performance with the same pipe surface, which is what it is achieved that between the heat transferring steam, which is referred to as primary steam, and the When the solution is boiling, a certain increase in the temperature difference is brought about. Because the boiling temperature the solution is proportional to its concentration, enables the boiling zone to be divided into several Stages at the same pressure of the secondary vapor formed by the boiling solution actually one some increase in the temperature difference in the first stages by 1 ° to 3 ° C.

This evaporator has the disadvantage that the heat of the secondary steam cannot be recovered. The total heat consumption of the evaporator is therefore very high.

The prior art also includes a number of embodiments of flash evaporators (Lu eg er, Lexikon der Technik, margin 16, pages 320,321).

One of these embodiments describes a single-stage flash evaporator with a vertical one cylindrical housing, which pipe socket for supplying the salt water to be desalinated and for Has draining the non-evaporated salt water. In the housing sits coaxially to the evaporation ring space a capacitor with a jacket. The vapor is passed through the evaporation annulus, the when the superheated salt water evaporates. There are openings on the jacket for the passage of steam, Distillate and non-condensable gases provided.

Another embodiment describes a multi-stage flash evaporator, its housing is rectangular and nozzle for supplying the heated salt water to be desalinated and to the Has draining the non-evaporated salt water. The interior of the case is vertical Partition walls divided into stages. Each stage has an evaporation chamber, a condenser and Openings for the passage of the steam of the salt water to be evaporated, the distillate and the non-condensable gases. The heat to be added to this evaporator to heat the salt water in the The heater before desalination is considerably smaller because the Evaporation heat to preheat the salt water flowing in the condenser tubes is exploited. Such multi-stage flash evaporators are particularly suitable for the generation of over 100 tons of distilled water per day.

Finally, expansion evaporators are also known, in which the salt water evaporates generated steam is compressed in the compressor and then fed to the heating device. In addition to the Compressor required effort, large heating surfaces are also required. In addition, there is the risk of a rapid build-up of scale.

If the expansion evaporator described above for smaller capacities, so for a Producing less than 50 t of distilled water per day, they have to use the Disadvantage that they require a lot of space, which is particularly large when installed on ships Disadvantage is. In addition, the amount of fresh water generated is very small in relation to its weight.

The object on which the invention is based is therefore to develop a multi-stage expansion evaporator of the type described at the outset to be created when space is limited, based on Weight that enables a large amount of fresh water to be produced.

This task is performed with the multi-stage expansion evaporator of the type described above achieved in that the housing and the capacitor with its jacket divided into individual steps over the entire height by radially extending partitions are, with openings for the passage of the salt water, the distillate and the non-condensable G.ise are provided at each stage.

The multi-stage flash evaporator according to the invention has the advantage that it can be used to produce large amounts of fresh water, based on weight, and that the space requirement is very small, so that the installation of the flash evaporator on ships is particularly suitable for fresh water production. A relaxation evaporator with eight to ten stages generates around 301 fresh water per day with a heat consumption of 150 to 180 kcal / kg. A flash evaporator with five to six stages generated at a heat rate from 200 to 220 kcal / kg daily ^r i to 10 tons of fresh water. The space requirement of the former version is 30%, that of the latter version 40 to 45% less than that of the well-known Entsnannunirsvur-

rectangular damper with the same number of stages.
The advantage of the multi-stage according to the invention

Tabel

Flash evaporator compared to currently used evaporators for the recovery of fresh water from salt water is shown in the following table.

product [.and Lei Siu- More specific Dimensions in broad mm height volume Accruing weight stung window- Steam- of the Ver distillate in the Be in number consumption length steamer related to drove in the Ver- state in Steam boat- 1320 2125 volume in t / day kg / kg 2419 2621 in' t / m'h ι invention USSR 25th 6th 0.31 1710 2419 2621 4.8 5.21 2.5 WEIR England 20th 2 0.88 2413 2130 2280 15.0 1.33 5.8 F-T England 30th 2 0.88 2413 15.0 2.0 6.1 BUCKLEY England 25th 3 0.75 2130 2210 2280 10.6 2.36 & TAYLOR 1680 2360 AQUA BOTTLE England 30th 3 0.725 2280 11.5 2.61 CLEAVER United States 31 2 0.85 2360 9.34 3.32 BROOKS (Aqua-Chem)

The invention is explained in more detail, for example, with the aid of the drawings.

I'ig. 1 schematically shows a longitudinal section through a first embodiment of a stress relief valve;

F i g. 2 is a section along line 11-11 of FIG. 1;

Fig. 3 shows a second embodiment of a multi-stage flash evaporator in longitudinal section;

F i g. 4 is a section along line III-III of FIG. 3.

The multi-stage flash evaporator shown in FIGS has a cylindrical housing I and a heater 2. In the housing is coaxial too A condenser 3 with a jacket 4 is arranged in the evaporation annulus. The case I and the Capacitor 3 with jacket 4 are over the entire height by radially extending partition walls 5 in divided into individual stages, with each stage a section of the evaporation ring and a condenser assigned. The salt water to be desalinated is supplied to the housing 1 through the pipe socket 6 fed. The pipe socket 7 serves to discharge the non-evaporated salt water.

At its end face, the capacitor 3 is closed by covers 8 and 9, which are not channels shown for overflowing the salt water from the condenser of one stage into that of the other stage are provided. On the cover 8 ties capacitor 3 is the Rohrstutyen 10 for supplying the cold Fortified by salt water.

On the lower part of the jacket 4 are a Röhrst uzen Il for discharging the fresh water and a pipe socket 12 for discharging lull and non-condensable egg Gases attached.

Each partition 5 with the exception of the last The dividing wall of the successive stages has an opening 13 on its lower part, which is surrounded by distillate to the overflow of the distillate, an opening 14 above the distillate level for the air and the overflow non-condensable gases and an opening 15 on the part of the partition wall surrounded by the salt water for ile overflow of deep salt water from one stage into the next level. A separator 16 is located on the jacket 4 for the separation of the salt water irrigation carried out by the steam.

This multi-stage flash evaporator works as follows. Through the pipe socket 10 in Lid 8 of the condenser 3 is supplied with cold salt water, which successively through the pipes of the Condenser 3 flows, heated and then fed to the heating device 2 for further heating will. The heated salt water then flows through the pipe socket 6 in the housing 1 into the evaporation annulus section the first stage. In this annular space section, a pressure is maintained below the Saturation pressure is, which corresponds to the temperature of the supplied salt water, d. H. the salt water will overheat. The superheated salt water partially evaporates adiabatically and cools down in the process. Not that one Evaporated salt water runs through the opening 15 in the partition 5 into the evaporation annulus section the next stage, with adiabatic evaporation also occurring, which are successively in the the following stages repeated. The salt water that has not evaporated is released from the last stage through the pipe socket 7 discharged to the outside on the housing 1. The vapor formed by evaporation, entrained drops of salt water and formed non-condensable gases are fed into the separator 16. That one from them Steam freed from salt water droplets is led into the condenser 3, where it adheres to the pipe surfaces Condensed distillate, which flows to the lower part of the condensers 3 and through the opening 13 in the radial running partition 5 overflows into the next stage. The last stage becomes there ;. Distillate in The form of fresh water discharged through the pipe socket II in the housing 4 for consumption.

The non-condensable gases released during the evaporation flow through the opening 14 into the partition wall 5 from one stage to the other and are through the nozzle 12 on the jacket 4 from the last step removed.

The in the F i g. The embodiment shown in FIGS. 3 and 4 differs from that in FIGS. 1 and 2 shown in that in each stage a capacitor j with a jacket 4 sit / t, with jetler capacitor at his Front sides through the ceiling! 8 and 9 is complete. The cover 8 of each capacitor 1 of each Stage has a pipe socket / s 17 for the feed and a KohrsUity.cn 18 for the Abführuni: ties Sal / was-

sers. At the bottom of the shell 4 of each stage is with the exception of the first stage, to which the heated salt water from the heating device 2 is fed, the pipe socket 19 is attached for introducing the distillate from the previous stage. The pipe socket 11. Seated for the removal of the distillate from each stage also on the jacket 4. A separator 16 is attached to the jacket 4 of each stage.

. The embodiment of the Enlspannungsverdampfers shown in Figures 3 and 4 operates substantially like the reference to the f ⁱ g. 1 and 2 described. One difference is that the cold salt water is fed to the condenser 3 of each stage through the pipe socket 17 in the cover 8, the overflow of the salt water from the condenser of one stage to that of the next stage takes place via the pipe socket 18 in the cover 8. The Distillate in the condenser 3 is fed through the pipe socket II in the jacket 4 to the pipe socket 19 on the jacket 4 of the next stage. This embodiment has the advantage that the individual capacitors can be serviced individually. In addition, the evaporator is easier to adapt to the thermodynamically most favorable operating behavior.

For this 2 lilii

Claims (1)

Claim: Multi-stage expansion evaporator with a vertical cylindrical, with pipe socket for Supply of the salt water to be desalinated and provided for discharging the non-evaporated salt water Housing, inside of which a condenser with jacket coaxially to the evaporation annulus is arranged, the openings for the passage of steam, distillate and non-condensable gases has, characterized in that the housing (1) and the capacitor (3) with his Jacket (4) over the entire height through radially extending partitions (5) in individual stages are divided, with openings (15, 13, 14) for the passage of the salt water, the distillate and the non-condensable gases are provided in each stage.