DE2840066A1 - DEVICE FOR OBTAINING PURE WATER FROM SEA WATER - Google Patents

Description

28A0066

PATENT LAWYERS

WUESTHOFF - ν. PECHMANN - BEHRENS - GOET2

PROFESSIONAL REPRESENTATIVES BEFORE THE EUROPEAN PATENT OFFICE

MANDATAiRES agrees pres l'office europeen des brevets

DR.-ING. FRANZ WUESTHOFF DR. PHIL. FREDA WUESTHOFF (1927-1956) DIPL.-ING. GERHARD PULS (19J2-I971) DIPL.-CHEM. DR. E. BARBER OF PECHHANN DR.-ING. DIETER BEHRENS DIPL.-ING .; DIPL.-WIRTSCH.-ING. RUPERT GOETZ

D-8000 MUNICH SCHWEIGERSTRASSE phone: (089) 66 20 ji telegram: protectpatent telex: 524070

IA-5I 322

Patent application

Applicant: Snamprogetti S.p.A.

Corso Venezia 16, Milan / Italy

Title: Device for obtaining pure water from sea water

Addendum to patent 23 34 481

90981 B / 0705

DR.-INC. FRANZ TUESTHOFF

PATENT LAWYERS

DR. PHIL. FREDA TFUESTHOFF (1927-1976)

WUiZSTHOFF-v.PECHMANN-BEHRENS-GOETZ

dipl-incgerhard puls

DIPL.-CHEM. DR. E. BARBER OF PECHMANN PROFEjSIONAL REPRESENTATIVES BEFORE THE EUROPEAN PATENT OFFICE DR.-ING. BIDDERS BEHRENS

MANDATAIRES ΑσΗέΕ5 PRES l'oFFICE EOROPEEN DES BREVETS DIPL.-ING .; DrPL.-WIRTSCH.-ING. RUPERT GOET2

D-8000 MÜNCHEN 90 SCHWEIGERSTRASSE 2 phone: (089) 66 20 ji TELEGRAM: PROTECTPATENT TELEX: J 24 070

1Δ-51 322

description

The I) E-PS 2334481 relates to a device for G-ewinnung of pure water from sea water according to the multi-effect process with heat exchangers, separating tanks, feeds for sea water and pr imärdarapf discharges for salt solution and pure water as well as connection to a vacuum system, wherein a vertical column is divided into several cylindrical sections. These contain two film evaporators in the form of vertical tube bundles - designed as a circular segment in cross section without Jacket - and two tanks that are at the bottom with the upper tube plate of one of the film evaporators of the same section - in the last section without film evaporator, but connected to the discharge line for saline solution - and at the top with the lower tube plate of the film evaporator of the section above first section connected with the seawater feed extension - / * Finally, there is a bottle neck-like overflow at the Bottom of each container for the passage of the saline solution from the container to the underlying tube plates and for compensation the positive pressure difference. Openings for the exhaust of the steam are at the top of every container with the exception of the container provided in the first section. Finally, one or more Siphonrotrqfe) is used to withdraw the water at the bottom of each Section collecting condensate and for re-introduction at a middle point of the next section. Horizontal

/* are connected.

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arranged tube bundle exchangers ensure preheating the sea water with steam and inert gas lines connect the sections up to the vacuum system.

The additional application DE-OS 2625358 brings a further development of this device by the tube bundle exchanger for preheating the sea water in a continuous Tube is housed, which is in the containing the saline solution Container is located and this divided into two tubs.

The present invention brings a further modification of the device according to DE-PS 2 334 4-81 to the effect that for systems With a high throughput, vertically arranged tube bundle exchangers for preheating the seawater offer particular advantages, especially with regard to capital expenditure and energy consumption.

1 shows a longitudinal section through one of the sections of a column for desalination of seawater or brackish water from the following parts:

a) Vertical tube bundle film evaporator 1 without a jacket;

b) Container 2 for collecting the (brackish) water, connected at the bottom with the top tube plate of the film evaporator, this Container - in the last section without a film evaporator with the discharge pipe above the lower tube plate of the one above Section is connected. The tank is in the first section with the feed line for the sea or brackish water tied together.

c) Then there is a system at the bottom of each container allows the flow of water into the second container 4, the bottom plate of which is the upper tube plate 8 of the one below Filraverdampfers 1. This way it becomes a positive Pressure difference between container and film evaporator eliminated.

d) Finally, in the upper part of the side wall, each can be found

Container - _N with the exception of the container of the first section -

)
Openings 3 / and

*) to extract the steam ^ _{0g815 / 0705}

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e) one or more siphon pipe (s) for draining off the condensate that collects at the bottom of each section and introducing it

• in the middle of the next section. (Tube bundle) -

f) The / heat exchanger 5 is used to preheat the feed

Water with steam obtained in each section.

g) Finally, there are line systems for inert gases, which may be in the vacuum system, between the individual sections available.

The shell and tube film evaporators in each section has a cross section in the form of a segment of a circle and the heat exchanger 5 for preheating the feed Water has a circular cross-section and is arranged vertically. Its lower tube plate rests on the parting line for next section and the top tube plate is in the heat with the parting line of the section above it expandable connection 6 connected, which expansion differences of the column and the tube plates by different materials capable of balancing and having a single passage for upward flow in the section. He is located in the circle segment, which is from the film evaporators 1 is still being released.

The last condenser below the last section is a horizontal tube bundle condenser with fixed Tube plates on diametrically opposite parts of the column and is used to condense all that is present in the last section Steam.

]? ig. 2 shows a cross section according to AA from FIG. 1, from which the position of the heat exchanger 5 and the lamellar separators 3 ′ including the upper container for (brackish) water 2 ¹ can be seen.

The invention is further illustrated by the following examples.

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example 1

Initial values:

Sea water salinity 35,000 ppm pH at 2O ⁰ G 8.1 temperature 26 ⁰ G Primary steam 3 atu 135 ⁰ G Fresh water output 1,500 m ⁵ / h Fresh water temperature 46 ⁰ G Salinity of fresh water 15 ppm

Desalination with a vertically arranged heat exchanger for preheating "is particularly interesting for large systems, as can be seen from the following table in the the main characteristics of two systems are combined, i.e. with a horizontal and a vertical arrangement of the heat exchanger for preheating.

horizontal vertical m Number of sections 15th 15th m Number of columns 2 2 m 0 1 * column 8 m 6.5 0 2nd column 8 m 6.5 kWh / m ⁵ Height of 1st column 37.2 m 41.4 Height of 2nd column 40.8 m 45 τη Electricity demand 2.35 kWh / m ³ 1.86

The embodiment with a horizontally arranged tube bundle exchanger for preheating the sea water requires tube plates with a diameter of 2.45 m, connected with large ones Problems with the construction and support of the tube bundle inside each section due to their own weight and the

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■ Γ

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"Considerable sealing problems on the flanges due to possible Air intake from the outside and finally - what is probably most important - that practical handling of the tube bundle Such a size is not possible if they are removed from the column for repair or maintenance or used in it should.

The fact that in the device according to the invention The total length of the two columns is 8.4 m greater than in the known embodiment with horizontally arranged heat exchangers for preheating, is not intended to lead to the deceptive view that a substantial decrease in Diameter is given by the omission of the outer distributor for the exchanger, which inevitably consists of a high-quality Material must be made (copper / nickel 90/10), the reinforcement must also be made of an expensive material, see above that considerable initial costs can be saved, as can be seen from the following example.

Example 2

Output data:

Salt content of the sea water pH value at 20 ⁰ C sea water temperature Primary steam Fresh water output Fresh water temperature Salt content of the fresh water

With the lower throughput of 535 m / h, which is considered to be medium to higher, the advantages achieved according to the invention are not as clear as in Example 1, however

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35 000 m ⁵ C. ppm 8.1 ppm 26 ° C. 3 atü and 135 ⁰ C 535 46 ° 15th

⁰ I.

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nevertheless represents a "considerable material saving fixed.

horizontal vertical Number of sections 15th 15th Number of columns 2 2 0 1st column 4.7 m 4.35 m 0 2nd column 4.7 τη 4.35 τη Height of 1st column 37.2 m 39.8 m Height of 2nd column 40.8 m 44 m Electricity demand 2.35 kwH / m ⁵ 1.86 kwH / m ⁵

This comparison is closer and allows the actual economic benefits to be assessed more precisely.

The total weight of the two columns is about 33 t less. The very expensive copper / nickel alloy accounts for 5.5 t of this 90/10 and the remainder on carbon steel which is generally clad with expensive material or in an expensive manner is.

In the case of a unit with a laterally extendable, horizontally arranged tube bundle exchanger for preheating the seawater outside the columns must be a scaffold with working platforms for each section and lifting equipment for moving in and out of the Heat exchangers may be provided.

According to the invention, both the evaporator tube bundle as well as the preheating tube bundle vertically from the top of the columns be extended. So you only need a hoist of the appropriate power above the head of the columns, which can serve both columns and which rests on a platform on the column heads. So you need for the work outside of the column no scaffolding, which has an estimated weight of about 140 t and can reduce the workload for

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save the erection of such a G-scaffold.

A powerful pump for the film evaporator will be cheaper if the hydraulic pressure that has to be overcome with the same performance. can be lowered from 180 to 120 m

even
can. All of this influences / the creation time, a factor that should not be overlooked in the current market situation.

Besides the weight reduction and thus a reduction In addition to the investment costs, savings in operating costs are also achieved through lower power consumption.

For an annual output, spread over 330 working days and with electricity costs of 30 lire / kWh, the following savings result; (2.35 - 1.86) χ 1,500 χ 24 x 330 χ 30 = 174,636,000 lire annually, calculated for example 1, and for example 2 (2ß5 - 1.86) χ 535 x 24 x 330 χ 30 = 62,286,840 lire.

The device according to the invention is therefore not only suitable for large-scale systems but also for systems with medium performance · in the order of magnitude of 350 to 400 m / h, however is it of incomparable importance for systems with high

• z

genes from 800 to 1 000 in / h and above, which ever larger Experience spread.

Claims

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Claims (1)

Claim! 1. Device for obtaining pure water from sea water or brackish water by the multi-effect process containing one or more vertical columns, divided into several cylindrical sections, each containing: a) Film evaporator with vertical tube bundles - designed as a segment of a circle in cross section without a jacket - b) sump that is at the bottom with the top tube plate of the film evaporator of the same section - in the last section without film evaporator, but connected to the discharge line for saline solution - and at the top with the lower tube plate of the film evaporator of the overlying section in the first section connected to the feed line - connected are; c) a bottle neck-like overflow at the bottom of each sump for the transition of the saline solution from the container to the underlying tube plates and to compensate for the positive pressure difference; d) openings on the upper side of each collection container except the container in the first section; 909815/0705 - 2 - - 2 - 1A-5 e) one or more siphon pipe (s) for the drainage of the floor each section collecting condensate and for re-introduction at a central point of the next section; f) Tube bundle exchanger for preheating the sea water with Steam; g) Inert gas lines from section to section to the vacuum system; h) an end capacitor with horizontal tube bundles whose Tube plates are fixed diametrically on opposite parts of the column under the last section, / characterized in that the tube bundle exchanger is arranged vertically. / * according to OE-PS 23 34 481 909815/0705