DE2135685B2 - MULTI-STAGE EXPANSION EVAPORATOR - Google Patents

Description

The invention relates to a multi-stage expansion evaporator with a vertical cylindrical, with pipe socket for supplying the salt water to be desalinated and for discharging the non-evaporated water Housing provided with salt water, inside a condenser coaxially to the evaporation annulus is arranged with a jacket, the openings for the passage of steam, distillate and non-condensable Has gases.

An evaporator with a multi-part liquid space is already known (DT-AS 10 66 541), with in Boiling tubes are arranged in the individual liquid spaces. This well-known evaporator is used for Evaporation of solutions, with the cross-sections of the not yet evaporated solution between the individual fluid spaces are adjustable.

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 is achieved that between the heat-emitting 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 certain increase in temperature difference in the first stages by 1 ° to 3 ° C.

This evaporator has the disadvantage that there is no recovery of the heat from the secondary steam. The total heat consumption of the evaporator is therefore very high.

The prior art also includes a number of embodiments of flash evaporators (Lueger, Lexikon der Technik, Volume 16, page 320,321).

One of these embodiments describes a single-stage expansion evaporator with a vertical cylindrical housing which has pipe connections for supplying the salt water to be desalinated and for discharging the salt water that has not been evaporated. A condenser with a jacket is located in the housing coaxially to the evaporation * ™ * space. The vapor produced when the superheated salt water evaporates is led through the evaporation ring space. Openings for the passage of steam, distillate and non-condensable gases are provided on the jacket. Another embodiment describes a multistage expansion evaporator, the housing of which is rectangular and has nozzles for supplying the heated salt water to be desalinated and for discharging the non-evaporated salt water. The interior of the housing is divided into stages by vertical partitions. Each stage has an evaporation chamber, a condenser and openings for the passage of the steam from the salt water to be evaporated, the distillate and the non-condensable gases. The heat to be supplied to this evaporator for heating the salt water in the heater before desalination is considerably smaller, since the heat of evaporation is used to preheat the salt water which flows in the condenser tubes. Such multi-stage flash evaporators are particularly suitable for the production of over 1001 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 ίο Compressor required effort, large heating surfaces are also required. In addition, there is the risk of a rapid build-up of scale.

If the above-described relaxation

evaporator for smaller capacities, so for one

.15 Producing Less Than 501 Distilled Water

should be used per day, you have the

Disadvantage 'that they require a lot of space, what

especially when installed on ships

Disadvantage is. In addition, the freshwater volume generated is

ge very small for their weight.

The object on which the invention is based is therefore to develop a multi-stage expansion evaporator of the type described above to be created with a small footprint, based on Weight that enables a large amount of fresh water to be produced.

This task is performed with the multi-stage flash evaporator of the type described above solved in that the housing and the capacitor so with its jacket over the entire height through radially running partitions are divided into individual steps, with openings for the passage of the salt water, of the distillate and the non-condensable gases are provided in each stage.

The multi-stage flash evaporator according to the invention has the advantage that it is related on the weight, can produce large amounts of fresh water and the space requirement is very small, so that the Installation of the flash evaporator on ships is particularly suitable for the extraction of fresh water. A flash evaporator with eight to ten stages generated with a heat consumption of 150 to 180 kcal / kg about 30 tons of fresh water daily. A flash evaporator with five to six stages produces at one Heat consumption of 200 to 220 kcal / kg daily 5 to 101 fresh water. The space required by the former version is 30% smaller, that of the latter design is 40 to 45% smaller than that of the well-known relaxation

(f

damper of rectangular design with the same stage expansion evaporator compared to currently available

Number· . Turned VppHnmnfnrn inr Ρ.ηικίηηιιηίτ »ιΛη CllftiuaccAi"

The advantage of the multi-level table according to the invention

used evaporators for the extraction of fresh water from salt water - is shown in the following table.

product country Lei
stung Stu
fe i- Specifical fishermen
Vaccine Dimensions in broad mm height volume
of the Ver Accruing
distillate weight
in the Be φ in number consumption Longing steamer related to
the Ver drove in Steam boat state in ft volume in
t / m ^y f t / day kg / kg 1320 2125 m » 5.21 t I. invention USSR 25th 6th 0.31 1710 2419 2621 4.8 1.33 2.5 I. WEIR England 20th 2 0.88 2413 2419 2621 15.0 2.0 5.8 » F-T England 30th 2 0.88 2413 2130 2280 15.0 2.36 6.1 BUCKLEY England 25th 3 0.75 2130 10.6 & TAYLOR 2210 2280 2.61 b AQUA BOTTLE England 30th 3 0.725 2280 1680 2360 11.5 3.32 CLEAVER
BROOKS
(Aqua-Chem) United States 31 2 0.85 2360 9.34

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

F i g. 1 shows schematically a longitudinal section through a first embodiment of a flash evaporator,

F i g. Figure 2 is a section taken on line 11-11 of Figure 1;

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

F i g. Figure 4 is a section along line 1II-I11 of Figure 4. 3.

The in F i g. 1 and 2 shown multi-stage flash evaporator has a cylindrical housing 1 and a heating device 2. A condenser 3 is coaxial with the evaporation annulus in the housing a jacket 4 is arranged. The housing 1 and the capacitor 3 with the jacket 4 are all over Height divided into individual steps by radially extending partition walls 5, each step a Section of the evaporation annulus and a condenser are assigned. Through the pipe socket 6 is the housing 1 is supplied with the salt water to be desalinated. The pipe socket 7 serves to discharge the not 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 of the condenser 3 is the pipe socket 10 for supplying the cold Fortified by salt water.

A pipe socket 11 is located on the lower part of the jacket 4 for discharging the fresh water and a pipe socket 12 for discharging air and non-condensable Gases attached.

Each partition 5 with the exception of the last partition of the successive stages has on Its lower part, which is surrounded by distillate, has an opening 13 to the overflow of the distillate, above the distillate level an opening 14 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 the overflow of the salt water from one stage to the next stage. A separator 16 is seated on the jacket 4 to separate the salt water carried 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 is overheated The overheated 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 fed into the condenser 3, where it adheres to the pipe surfaces The distillate condenses, which flows to the lower part of the condensers 3 and through the opening 13 in the radial direction running partition 5 overflows into the next stage. From the last stage, the distillate is turned into The form of fresh water is discharged through the pipe socket 11 in the housing 4 for consumption.

The non-condensable gases released during the evaporation flow through the opening 14 in the partition wall 5 from one stage to the other and are through the nozzle 12 on the jacket 4 from the last 2 runs away.

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 a capacitor 3 with a jacket 4 is seated in each stage, each capacitor at its End faces by the cover 8 and 9 is completed. The cover 8 of each capacitor 3 of each Stage has a pipe socket 17 for the supply and a pipe socket 18 for the discharge of the salt water

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 for the removal of the distillate from each stage is also located on the jacket 4. The jacket 4 of each stage is a separator 16 attached.

The in the F i g. The embodiment of the flash evaporator shown in FIGS. 3 and 4 works essentially as described with reference to FIGS. 1 and 2. One difference is that the cold salt water the condenser 3 of each stage is fed through the pipe socket 17 in the cover 8, the The overflow of the salt water from the condenser of one stage into that of the next stage takes place via the Pipe socket 18 in the cover 8. The distillate in the condenser 3 is through the pipe socket 11 in the Jacket 4 fed 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. The vaporizer is also lighter adapt to the thermodynamically most favorable operating behavior.

For this purpose 2 sheets of Zciclinunsicn

Claims (1)

Claim: Multi-stage expansion evaporator with a vertical cylindrical housing provided with pipe connections for supplying the salt water to be desalinated and for discharging the non-evaporated salt water, inside of which a condenser with jacket is arranged coaxially to the evaporation annulus, the openings for the passage of steam, distillate and non-condensable Has gases, characterized in that the housing (1) and the condenser (3) with its jacket (4) are divided into individual steps over the entire height by radially extending partition walls (5), with openings (15, 13, 14) for the passage of the salt water, the distillate and the non-condensable gases in each stage.