FR2534293A1 - IMPROVEMENTS IN WATER DESALINATION PLANTS WITH OR WITHOUT JOINED PRODUCTION OF ELECTRICAL ENERGY FROM HOT AND COLD WATER SOURCES HAVING A LOW DT IMPLEMENTED IN AN OPEN SUBATMOSPHERIC PRESSURE CYCLE - Google Patents

Abstract

THE INVENTION RELATES TO IMPROVEMENTS CONCERNING THE FIELD OF MACHINES OPERATING AT SUBATMOSPHERIC PRESSURE AND INTENDED TO PRODUCE DESALINATION OF WATER WITH OR WITHOUT ELECTRICAL AND OR MECHANICAL ENERGY FROM TWO SOURCES OF WATER GENERALLY SAUMATURATED AND LOWER THAN 100 TEMPERATURES IN TEMPERATURE WITH LOW DT BETWEEN THEM. THE INVENTION MORE PARTICULARLY CONCERNS EMBODIMENTS IN REINFORCED CONCRETE OF SAID MACHINES. THE INVENTION ENSURES THE ABSOLUTE AIR-TIGHTNESS OF A MULTICELLULAR ENCLOSURE 1 HOUSING THE BOILER 5 AND THE CONDENSER 6 BY IMMERSION IN WATER 3 AT ATMOSPHERIC PRESSURE CONTAINED IN A TANK 2 SUPPORTED BY A FRAME 17, ALL OF THEM BASED ON SUPPLY BINS 18 AND 19 BASED ON A BASE 34. THE ASSEMBLY IS A SELF-GENERATING WATER DESALINATION WATER TOWER WITH OR WITHOUT JOINT ELECTRIC AND OR MECHANICAL ENERGY PRODUCTION.

Description

The present invention relates to improvements to installations for the production of electrical energy and desalination from hot and cold saline sources having a low #T, implemented in an open cycle.
To date, we know the desalination processes and equipment using "flash" evaporation. The process for the joint production of electricity and fresh water by low pressure open cycle is also known, using natural or artificial low heat sources. Furthermore, it has been proposed to lower the cost of the bulky enclosures necessary in these processes by making them out of reinforced concrete (for example French patent N 981254 in the name of the CNRS).

 The inventors themselves have proposed French patent application N 81 20506) means intended to ensure the circulation of fluids and to economically produce the rotors and the enclosures necessary for these installations.

It is recognized that considerable downsizing is necessary to ensure the dissemination of these types of materials, but without thereby compromising their reliability. For example, the reinforced concrete embodiments proposed to date certainly did not help to ensure over time, airtightness under pressure from cracks and capillaries in the concrete and aging of the plasters
On the other hand, in the CNRS installation mentioned above, pumps are used on the water inlet and outlet pipes, sources of air infiltration, in our opinion, at the flanges, trees and controls.

 In general, most of the proposed installations use single or double curvature enclosures (torus cylinders, spheroids) justified in the case of metal fabrication but unsuitable for current reinforced concrete construction due to the high cost of their formwork and reinforcement. More generally, these forms result in a too high ratio of volume closed under vacuum per surface of evaporation and condensation trays.

Finally, no satisfactory process has been proposed allowing
to manufacture turbine discs suitable for very low pressures
sions, light and inexpensive while remaining resistant to high rotational speeds Dr, in the aforementioned types of installations, dedicated to programs where profitability constraints are drastic, the cost of conventional turbines weighs too much on the cost alone overall tolerable.

 The present invention relates to means intended to improve installations of the aforementioned type by correcting the above-mentioned faults 9 it would relate to the implementation of reliable units accessible to concrete and public works companies.

 According to a characteristic of the invention, the enclosure or enclosures made of reinforced concrete and containing the single or multiple stage evaporation and condensation plates is / are isolated from the outside air by water at pressure and - mospheric. This arrangement, which is very favorable for the conservation of concrete and plaster, is partially carried out in floating ionations (energy from the seas for example); but to date vacuum ground installations do not use general liquid protection, # which has moreover proven itself in other applications and at different pressures (pressurized hydraulic seals); they are satisfied with coatings, varnishes, paints, intended to block the pores and microcracks of the concrete, particularly insufficient in the face of pressurized air.

In the case of water protection, the inevitable percolation of water through the pores of plasters and concrete does not affect the level of vacuum in the enclosures and the water supply remains negligible compared to the flow rates important circulating in these installations.

 According to the invention, the low internal pressure enclosures are immersed as much as possible, or preferably entirely, in reservoirs more or less closely matching their shapes. Said tanks can serve as a water tap or as a reserve for the water produced by the installation.

 According to another characteristic of the invention, the low-pressure chambers are preferably given a flattened, orthogonal and parallelepipedal volume, easy to produce in concrete, and suitable for all kinds of site rationalizations, such as the use of prefabricated slabs. forming lost formwork. The crush resistance of these flat boxes is obtained by vertical walls or partitions forming internal beams and dividing. the scopes so that. the bending forces remain low. The whole would have the shape of a multi-cellular box floor; we could of course give profiles allowing to collect the cutting forces, such as cut edges, vutains, usual in the construction of foundation rafts. The box would simply rest on wedges or joists placed at the bottom of the tank where it is submerged, which would leave free the game of dilations. According to this embodiment in accordance with the invention, a favorable ratio of 0.5 m3 per m 3 of useful surface would be obtained, and the vertical partitions would make it possible to channel the steam and the water to avoid turbulence.

 According to another characteristic of the invention, in order to avoid the interposition of pumps on the water inlet and outlet pipes, detrimental to the airtightness of the outside air, circulation is organized in the enclosure or the vacuum enclosures by simple effect of vessels communicating between lower tanks artificially maintained at different variable heights depending on optimum operating conditions (variable according to atmospheric pressure and with the aim of consuming minimum pumping energy) and the evaporation and condensation trays located. an average between 7 and 10.50 m above the level of the lower tanks. In this case, the rising and falling pipes simply dip their ends in the water of the tanks, and we can multiply small diameter pipes , each for example serving a cell of the box. This arrangement makes it possible to regulate the flow rates by the action of shutter valves in the lower part of the risers; this arrangement also ensures simplifications of construction, it weakens the upper structure less than the large sections of pipe, it allows the use of industrial tubes of short diameter, in particular reinforced or similar PVC tubes, completely waterproof and non-corrodible.

 According to another characteristic of the invention, in the case where the installation is intended for the production of electrical energy and requires the use of a turbo machine, the rotor made of conventional baleen by fins assembled on a disc would be heavy and expensive; It is proposed according to the invention to make a simplified type of turbine disc adapted to the low pressures and temperatures involved. According to the invention, it is proposed to produce the rotor by joining two metal discs, the fins of which have come from manufacture by cutting and forming in a flat sheet; twisted at desirable angles of incidence, these fins would be fitted by means of notches and would produce, by their alternation, a profile which closely approximates the ideal profile of the prefabricated fins (milling, micro-fusion bores) of current turbines.

All of the discs welded to one another could be stiffened by stamping. Discs of this type would be lighter than usual discs, which would allow the use of self-lubricated Teflon bearings, eliminating the need for ball bearings.

 One of the preferred applications of the invention would relate to the production of a compact unit comprising an # integrated pumping station, a set of tanks forming foundations, a water tower located at a height of approximately 10 m above of these tanks, carried by sails or a framework, and containing a submerged box housing the condensing members and eva portion and associated with a turbo-machine; the set being self-sufficient in energy and providing fresh water from a set of solar saltwater basins producing the hot spring and the cold source.

The invention and the implementation will appear more clearly with the aid of the detailed description which follows, given with reference to the appended drawings in which
- Figure-1 shows a vertical section along AA of an embodiment of a machine according to the invention
- Figure 2 shows a vertical section along BB of an embodiment of a machine according to the invention
- Figure 3 shows a plan view along CC
- Figure 4 shows a plan view along DO
- Figure 5 shows a large-scale detail of an embodiment according to the invention according to E
- Figure E shows an example of an embodiment of a turbine rotor adapted to low temperatures and low pressures designed according to the invention.

 As can be seen particularly in FIGS. 1 and 2, the general enclosure 1 is made of reinforced concrete and contains the evaporator 5 and condenser 6 cells themselves produced by subdividing the general volume 1 by internal concrete partitions and partitions 7 .

 According to one of the main characteristics of the invention, the general enclosure 1, inside which prevails sub-atmospheric pressures produced in V1 and V2, is isolated from the outside air by water 3 at atmospheric pressure contained in at least one tank 2.

 Each evaporator or condenser cell encloses itself ~ a volume 8 of degassing a median plate S for supporting the pipes 27 for admission and distribution of water, a volume 10 of steam pro diction. On the steam path from production at the boiler 5 to the condenser 6 can be interposed a turbo-machine. The boiler 5 and the condenser 6 are respectively supplied with hot and cold water by the family of pipes 13, 13 '. The water supply 3 to the upper tank 2, and used for airtightness of the multicellular enclosure 1, is done by the piping 15 and a minimum level 12 is observed in operation so that the most of enclosure 1 is submerged.

 An additional tank 16 can constitute an additional fresh water reserve and increase the volume of the water tower. All of these tanks 1, 2, 16 are supported by a concrete or metal frame 17 and located with regard to the vacuum enclosure 1 den 7.5 and 10 m from the den floor to # make barometric flock "Greek families of pipes 13 and 14 soaking in the lower tanks 18 and 19 located substantially at ground level.

 There are five lower bins. The hot water is supplied by the Greek pump 21 which allows to choose the optimum water level 22 in the tank 18 according to the desired flow conditions and the atmospheric pressure of the moment. The outlet of cooled hot water is through the tank 19; the level of this tank which should allow the natural extraction of water is therefore chosen according to obtaining a correct level at 23. The phenomenon is identical on the cold side thanks to the pump 24, to the tanks 18 'and 19'. However, in order not to pollute the fresh water obtained after condensation of the steam, an exchanger 25 can be added to the cold circuit and immersed in a tank 20 in which the brackish cold water circulates thanks to the pump 26.

 A detail of embodiment of the multicellular enclosure 1 immersed in the water 3 contained in a tank 2 is shown in FIG. 5. After the use of slabs 28 Forming cofFrage lost on shims or reinforced concrete joists 29, a bituminous seal 30 , plastic, silicone or other is used. The multicellular box 1 is then produced using vertical formwork for the splits 7 and the outer walls. The intermediate plates 9 comprising the inlet pipas 27 in sealing are then installed and correctly repointed. Upper slabs 31 are placed so as to be able to flow the upper face of the enclosure 1. Expansion joints 32 are provided. The seal 30 is then taken up with a baleen to be coated entirely with the exterior of the box 1. When the subatmospheric pressure prevails in the box, the seal 30 will settle and even penetrate the pores of the baleen concrete to almost completely obstruct the micro-leaks. Immersion completely cancels air permeability and is very favorable for the aging of concrete and sealants.

 A general roof 33, for example made of asbestos cement, can be laid with a baleen to protect the water 3 and the entire water tower self-producing, from dirt and atmospheric agents in general.

 By way of explanation and without limitation, a production of 10 Kw of installed electrical power also produces 20 T / day of desalinated water. The multicellular enclosure 1 has external dimensions of 4.00 x 4.00 x 1.00 and is immersed in the water 3 contained in the tank 2 whose dimensions are 5.00 x S.D0 x 2.00 m. The assembly is placed on a concrete frame 17 at a height of 8 to 10 m from the ground. The tanks 18, 19, 20 on the ground also have external dimensions of 5.00 x 5.00, serve as the foundation for the assembly and are supported on a general sole 34. The evaporation 5 and condensation 6 plates have surfaces of 8 m2 each, the turbine rotor 11 has a diameter of 0.60 m.

 The assembly thus produced forms a self-produced freshwater water tower with or without joint production of electricity.

 L9adaptatiDn powers is easy by simply increasing the surfaces and flow rates used, and the power range preferentially targeted is from 10 to 200 Kw.

 Different devices can be selected in order to deliver the waterproofing of the multicellular box 1. First, when pouring concrete, a general metallic ama can be inserted into the thickness of the formwork itself. It would serve as the main reinforcement and sealing Additives can also be added to the water 3 if it is not drinkable, such as ash, pozzolan or any chemical solvent tending to clog the pores of the concrete. For the same purpose a general plastic sheet welded and glued to the concrete walls can wrap the box 1 and would tend to be pressed when the depression is achieved there.

 Still according to the invention, the rotor of the turbine 11 can be produced from a new mode particularly suited to the conditions of low temperatures and low pressures. Said rotor is obtained by assembling two resistant metal discs 34 and 35, for example made of stainless steel, each supplying by cutting half of the blades 36 of the rotor. The blades 36 are obtained by cutting 37 and a notch 38 is formed at the foot of each fin 38 for the fitting of the two discs.

This foot 39 of the blade 36, after cutting the notch 37, for example has a half width of said blade and is centered on it
A twist is then produced on each foot 39 of fins 36, then the body of the fin 36 is formed by stamping. The edges 40 of the blades 38 are machined, rounded at the leading edge and laminar at the trailing edges. The two discs 34 and 35 are then stamped and then assembled together by any known means. The rotor disc obtained is then light, resistant and of a manufacturing method much less expensive than manufactured by the usual methods.

Claims (14)

 1. Embodiment of a machine, composed of reinforced concrete enclosures 1, maintained at subatmospheric pressure, in which circulate sources of hot and cold water having a low natural or artificial ~ T, intended to produce desalination d with or without joint production of electricity and characterized in that the concrete enclosures 1 are produced in the form of multicellul boxes flush with 5 and 6 substantially ortho gonals, partially or totally submerged in a volume of water 3 at atmospheric pressure contained in a concrete tank 2, itself substantially orthogonal  2. Device according to claim 1 characterized in that the crushing resistance due to atmospheric pressure 53 exer- sing on the outer walls of the reinforced concrete caissons 1 is obtained by the implementation of posts, slits and interior partitions an reinforced concrete 7 planes or curves, the said partitions, splits and posts also serving to channel the fluids whether they are in liquid phase or in vapor phase, and also serving to prevent turbulence, and the whole thus forming a box multi-cell resistant 1.  3. Device according to claim 1 or 2 characterized in that the general volume of the multicellular box 1 is substantially parallelepiped flattened in the horizontal without, and that the horizontal surface ratio of the boiler and condenser trays 9 to the enclosed volume, is substantially 0 , 5 m3 for 1 ma, the said trays being produced in the same horizontal plane and the whole being enclosed by two horizontal reinforced concrete slabs, and by external partitions and internal partitions 7 substantially parallel and vertical and spaced about 1 .00 m.  4, Device according to any one of the preceding claims, characterized in that the air and water tightness of the multi-cellular reinforced concrete box 1 is improved by external coating of a product 30 of the bituminous, silicone or plastic coating type. on the concrete itself, the said concrete being subjected to an internal depression, or even by the use of a continuous metallic core, at the time of the pouring of the concrete, inside the walls itself and serving as reinforcements and ensuring sealing.  5. Device according to any one of the preceding claims, characterized in that the airtightness and water tightness of the multicellular box 1 in depression in water 3 at atmospheric pressure, are improved by adding particles to said water. very fine in suspension such as pozzolana, ashes; the said particles progressively and advantageously clogging the open pores of the concrete or the microcracks  6. Method of making a machine according to any one of the preceding claims, characterized in that the tightness of the multicellular box 1 is improved by the use of plastic sheets glued between them and on the concrete, and have been pirated and pressed against said concrete thanks to internal depression.  7 Machine according to any one of claims 1 to 6 characterized in that the multicellular box maintained at subatmospheric pressure is intended to produce desalination plants by "flash" evaporation of salt water with or without joint production of electricity.  8. Embodiment of a machine according to any one of claims 1 to 7, characterized in that the external tank 2 containing the sealing water 3 of the multi-cell enclosure 1 year vacuum also serves as a water bar, and the water 3 contained is soft and consumable and produced by dessa lamant in said cell enclosure 1.  9. Machine according to any one of the preceding claims, characterized in that the tanks 19 and 19 on the ground allowing water to be supplied and returned, forming the base and foundation 34 of a structure 17 carrying the water tower 2, and are d3a surface projected on the ground substantially equal to that of said water tower containing itself ~ even the submerged multicell box 1 and the whole forming a partitioned assembly, rigid, resistant and compact.  10. Device according to any one of claims 1 to 9 characterized in that each sub enclosure 5 and 6 obtained by dividing the multicellular box 1 has its own rising and falling pipes 13 and 14, the overall supply and the overall return hot and cold water being thus produced by a plurality of pipes of small section, said families of pipes 13 and 14 can be made of common plastic.  11. Embodiment of a machine according to claim 10 characterized in that the circulation and the regulation of the flow rate of the water introduced and withdrawn in a reinforced concrete box 5 or 6 at subetmospheric pressure is done without circulation pump, by effect of communicating vessels from tanks 18 or 19 located substantially at ground level but having a difference in level 22, and through said box 5 or 6 located at a height substantially equal to 10 m column of atmospheric water3, box 5 or 6 and the tank 18 or 19 being interconnected by the ascending and descending pipes 13 or 14, the low ends of which are submerged below the level of the water contained in the tanks 19 or 19.  12. An embodiment of a machine according to claims 10 or 11 characterized in that the regulation of the flow rate is obtained by at least one pump 21 on the hot side and a pump 24 on the cold side not located on the main inlet pipes 13 and deposit 14 of the water, but making it possible to maintain a determined level difference 22 at will in the supply tank 18, thus modifying the intensity of the communicating vessel.  13. Embodiment of a machine according to any one of the preceding claims, characterized in that its internal cleaning and descaling is carried out by circulation in an armed circuit of a bactericidal product, polyphosphate, solvent or the like, said circulation being carried out and controlled from the lower tanks 19,19, and by silt effect communicating through the concrete enclosures 5,6.  14. Embodiment of a machine according to claim 1, characterized in that the rotor of the turbine 11 used for the production of mechanical and / or electrical energy is of the type particularly suitable for low temperatures and low pressures, such as that of the blades or fins have come from manufacture by forming two flat, circular and thin metal discs, a few mm thick, each disc allowing half of the blades to be produced, the two discs being assembled between by welding, riveting, bonding or other.