OA20047A - Solar-powered continuous distillation assembly having efficient heat recovery. - Google Patents

Abstract

The invention relates to a distillation assembly (1) which, with the aid of solar energy (2), continuously evaporates a feed liquor (4). Said distillation assembly (1) comprises: a container (3) which contains the feed liquor (4), a container (5) in which the distillate (6) is collected, these containers (3, 5) being in thermal contact, and a compressor (7). The compressor (7) compresses the vapour which is produced by boiling the feed liquor (4) using the concentration of solar energy (2) and/or using negative pressure, into the distillate container (5) such that the vapour condenses there, and the evaporation enthalpy and thermal energy is returned to the feed liquor (4) by the thermal contact.

Description

Solar-powered continuous distillation assembly having efficient heat recovery.

The invention relates to a distillation assembly which, with the aid of solar energy, continuously evaporates a feed liquor.

Distillation is an effective method of remoxing substances dissolved in liquids or reducing their concentration. A key application is the extraction of fresh water from sait water and the production of bioethanol. For distillation to take place, the liquid has to be evaporated and the resulting vapour re-condensed. The évaporation of liquids is a very energy-intensive process. As such, effective and inexpensive energy sources and heat recovery are essential in distillation applications. Distillation plants that use solar energy for the évaporation process are well known. Distillation plants that use heat pumps for heat recovery are also well known. In the field of mechanical vapour recompression, the vapour (fumes) is/are compressed, raising the condensation température so that this vapour condenses on a surface that is in thermal contact with the feed liquor and thus the enthalpy of vaporisation contained therein is returned to the feed liquor. It is necessary to take into account that a liquid in which substances are dissolved has a higher boiling température than the pure liquid. Seawater boils at a température that is about 1°C higher than that for fresh water.

It is essential that the container of the liquid to be distilled and the container containing the compressed vapour hâve a good thermal contact and that thermally, the whole assembly is well insulated from the environment. For thermal insulation, double-walled vacuum-insulated borosilicate glass tubes hâve been tried and tested millions of times over and can be produced cheaply. They are used as solar collectors for the production of hot water and withstand particularly harsh environmental conditions, e.g. hailstorms.

Solar energy is, in itself, free of charge, however it consumes land because its power density is low. In addition, plants hâve to be built that can utilise the solar energy. Both of these cost money.

The invention is based on the task of producing as much distillate as possible in relation to the available power and the plant that has been invested in.

The invention solves this problem in that a container containing the feed liquor and a container in which the distillate collects are part of a distillation assembly, wherein these containers are in thermal contact and a compressor compresses the vapour, w hich is produced as a resuit of boiling the feed liquor by concentrating solar energy and/or by négative pressure, into the distillate container so that this vapour condenses there and the vaporisation enthalpy and thermal energy are returned to the feed liquor via the thermal contact, wherein these containers hâve a circular cross-section or a cross-section deviating thereof, e.g. an oval, elliptical, triangular or polygonal cross-section, and their surface is optionally corrugated and/or bears ribs in order to improve the heat transfer and to increase the évaporation and condensation surface, and in that there is a feed line and a discharge line for the feed liquor and a discharge line for the distillate, the feed and discharge being controlled by valves and/or pumps, and there is optionally a vacuum pump which générâtes a négative pressure in the container which contains the feed liquor, and/or the distillaton assembly is operated at high altitudes in order to lower the boiling température of the feed liquor.

The invention is explained below by means of drawings:

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Fig. 1: A distillation assembly (1) which is irradiated by sunlight (2), in which there is a container (3) containing the feed liquor (4) which, at this point, is in thermal contact with a container (5) in which the distillate (6) collects, wherein a compresser (7) compresses the vapour produced by boiling the feed liquor (4) into the distillate container (5) and in which there is a feed line (8) and a discharge line (9) for the feed liquor and a discharge line for the distillate (10), wherein optionally, there is a vacuum pump (11) which generates négative pressure in the container (3) containing the feed liquor (4).

Fig. 2: Variant A of the distillation assembly (1) in which a container (3) containing the feed liquor (4) is located in a container (5) containing the distillate (6) and the vapour which is produced by the évaporation of the feed liquor (4) with the aid of the energy sunlight (2) and is compressed by a compresser (7), and in which there is a feed line (8) and a discharge line (9) for the feed liquor (4) and a discharge line (10) for the distillate (6).

Fig. 3: Cross-section of variant A through the feed liquor (4), which is in a container (3) irradiated by sunlight (2) and the container (5) for the distillate.

Fig. 4: Variant B of the distillation assembly (1) in which a container (3) containing the feed liquor (4) is located in a container (5) containing the distillate (6) and the vapour which is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and is compressed by a compresser (7), and in which there is a feed line (8) and a discharge line (9) for the feed liquor (4) and a discharge line (10) for the distillate (6).

Fig. 5: Cross-section of variant B through tire feed liquor (4), which is in a container (3) irradiated by sunlight (2) and the container (5) for the distillate.

Fig. 6: Variant C of the distillation assembly (1) in which a container (3) containing the feed liquor (4) is in thermal contact via a membrane and/or contact surface (12) with a container (5) containing the distillate (6) and the vapour which is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and is compressed by a compresser (7), and in which there is a feed line (8) and a discharge line (9) for the feed liquor (4) and a discharge line (10) for the distillate (6).

Fig. 7: Cross-section of variant C through the feed liquor (4) which is located in a container (3) irradiated by sunlight (2) and which is in thermal contact with a container (5) for the distillate via

a membrane and/or contact surface (12).

Fig. 8: The distillation assembly (1) is located in a double-walled light-transmitting evacuated tube (13) wherein the outer tube (14) and the inner tube (15) are translucent and a solar radiation absorbing layer can be found on the surface (16) or part of the surface (16) of the distillation assembly (1). A heat exchanger (17) is located inside the double-walled evacuated tube (13).

Fig. 9: The distillation assembly (1) in a double-walled evacuated tube (13), wherein the outer tube (14) is translucent and the inner tube (15) is translucent (variant A) or non-translucent (variants B and C) and serves as a container for the feed liquor and/or the distillate and carries a solar radiation absorbing (variants B and C) layer. A heat exchanger (17) is located inside the double-walled evacuated tube (13).

Fig. 10: The distillation assembly (1) with an electronic regulator (18) and control and/or signal lines (19) whiçh is irradiated by sunlight (2), in which there is a container (3) which contains the feed liquor (4) which, at this point, is in thermal contact with a container (5) in which the distillate (6) collects, wherein a compressor (7) compresses the vapour produced by boiling the feed liquor (4) into the distillate container (5) and in which there is a feed line (8) and a discharge line (9) for the feed liquor and a discharge line for the distillate (10). There is level indicator (20) in the container (3) for the feed liquor (4). The droplets produced during boiling are intercepted by a splash guard (21), e.g. a labyrinth, through which the vapour flows. The electronic regulator (18) Controls a pump (22) that delivers the feed liquor (4) to the container (3) and a valve (23) that Controls the outflow of the feed liquor (distillation residue). A filter (24) removes or reduces unwanted impurities which are présent in the vapour of the feed liquor. A level indicator (25) is provided in the container (5) for the distillate (6), and a valve (26) is controlled in the discharge line (10) in such a way that the level of the liquid distillate (6) is above the discharge line (10) so that no vapour can escape.

Fig. 11 : The distillation assembly (1), shown from the side, is inclined and oriented substantially normal towards the solar radiation. The arrangement consisting of the distillation assembly (1) and parabolic trough mirror (27) is held in position by a frame (28), part of which is formed by a D shaped tube (29).

Fig. 12: The distillation assembly (1), shown from the front, is inclined and oriented substantially normal towards the solar radiation. The arrangement consisting of the distillation assembly (1) and parabolic trough mirror (27) is held in position by a frame (28), part of which is formed by a D shaped tube (29). The distillation assembly (1) is illuminated with solar radiation (2) via the parabolic trough mirror (27).

Fig/lS: A parabolic trough mirror (27), in the focal line of which the distillation assembly (1) is located, is mounted horizontally and rotatably. The distillation assembly is curved upwards at one end (30)

so that the feed liquor and distillate do not ilow into the compresser or turbine and curved downwards at the other end (31) so that the distillate can be tapped there.

Fig. 14: The distillation assembly (1) is erected as a solar tower (32) and surrounded by mirrors (33) which direct the solar radiation (2) onto the solar tower (32). Depending on the topography of the installation site, it may be necessary to place the distillation assembly on a platform (34) so that it can be illuminated along its entire length.

Fig. 15: Variant A of the distillation assembly (1) as a cross-section along the central axis, in which a container (3) containing the feed liquor (4) is located in a container (5) containing the distillate (6) and the vapour produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) with a radial compresser turbine (35), wherein the vapour (36, small arrows) is compressed from the inside to the outside and directed to the area above (37) and below (38) the compresser. Above the compresser (35) there is a radial turbine (39) which is driven by the vapour (36, small arrows) and drives the compresser (35) via an axle (40), wherein the vapour (36, small arrows) flows from the outside to the inside. A feed line (8) and a discharge line (9) are provided for the feed liquor (4) as well as a discharge line (10) for the distillate (6).

Fig. 16: Variant B of the distillation assembly (1) as a cross-section along the central axis, in which a container (5) containing the distillate (6) and the vapour produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (21 is located in the container (3), with an axial compressor turbine (41). Above the compressor (41) there is a radial turbine (39) which is driven by vapour (36, small arrows) and drives the compressor (4 i) via an axle (40), wherein the steam (36, small arrows) flows from the outside to the inside. A feed line (8) and a discharge line (9) are provided for the feed liquor (4) and a discharge line (10) for the distillate (6).

Fig. 17: Variant C of the distillation assembly (1) as a cross-section along the central axis, in which a container (3) containing the feed liquor (4) is in thermal contact via a membrane and/or contact surface (12) with a container (5) containing the distillate (6) and the vapour produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) with a Roots compressor (42). The Roots compressor (42) is driven by an electric motor (43) and compresses the vapour (36, small arrows) from the left tank (3) into the right tarde (5). A feed line (8) and a discharge line (9) are provided for the feed liquor (4) and a discharge line (10) for the distillate (6).

Fig. 18: Variant C of the distillation assembly (1) as a cross-section through the Roots compressor (42) normal to the central axis. The Roots compressor (42) compresses the vapour (36, small arrows).

In variant A of the invention (Figs.2 and 3), the container (3) containing the feed liquor (4) is located in a container (5) containing the distillate (6) and the vapour, wherein the containers (3, 5) are in thermal

₅ 20047 contact, wherein the vapour is formed by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and compressed by a compresser (7) so that it condenses on the walls of the distillate container (5) and releases the inhérent thermal enthalpy of vaporisation and thermal energy to the feed liquor container (3) in order to return the heat to the feed liquor (4). In this case, the light from the sun (2) pénétrâtes the outer container (5 ) that contains the compressed vapour, the walls of which are designed to be transparent to solar radiation.

In variant B of the invention (Figs.4 and 5), a container (5) containing the distillate (6) and the vapour is located in the container (3) containing the: feed liquor (4), wherein the containers (3, 5) are in thermal contact, wherein the vapour is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and compressed by a compresser (7) so that it condenses on the walls of the distillate container (5) and releases the inhérent thermal enthalpy of vaporisation and thermal energy to the feed liquor container (3) in order to return the heat to the feed liquor (4). In this case, the light θα from the sun (2) strikes the outer container 13) which contains the feed liquor.

In variant C of the invention (Figs.6 and 7), a container (3) containing the feed liquor (4) is in thermal contact, via a membrane and/or contact surface (12) with a container (5) containing the distillate (6) and the vapour, wherein the vapour is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and compressed by a compressor (7) so that it condenses on the walls of the membrane or contact surface (12) and releases the inhérent thermal enthalpy of vaporisation and thermal energy to the feed liquor container (3) in order to return the heat to the feed liquor (4). In this case, the radiation from the sun (2) strikes the feed liquor container, and the distillation assembly (1 ) can be turned so that, if possible, only the feed liquor container is illuminated, or it can strike both types of containers (3, 5), in which case the solar energy is transferred to the feed liquor container by heat conduction.

The feed liquor (4) is continuously supplied (8) and discharged (9) in ail three variants (1) and the inflow and outflow quantity is controlled so that the level of the feed liquor (4) remains within a certain range and the feed liquor retains a liquid consistency. The distillate (6) is continuously discharged (10) and the discharge quantity is regulated so that the level of the distillate is above the discharge lines (10) so that no vapour can escape. The regulator can be manual or automated (e.g. electronic and/or mechanical). Sight glasses may be provided to support the manual control, in order to make the level of the liquids (4, 6) visible. For the automated control, sensors are provided which transmit the level to the control system in order to generate a control signal for valves and pumps. In addition, one or more heat exçhangers may be provided to keep the discharge fluid as hot as possible, by supplying the heat of the outflowing feed liquor (9), the distillation residue, and/or the outflowing distillate (10) of the feed liquor.

The solar energy (2) can be supplied through concentration with a parabolic trough mirror, a Fresnel

min-or or a Fresnel lens, in the focal line of which the distillation assembly is located, or by a plurality • of mirrors, in which case the distillation assembly is constructçd as a tower, a so-called solar tower, and is surrounded by these min-ors which concentrate the solar energy onto the solar tower. However, the solar energy can also be supplied directly to the distillation assembly, in which case a vacuum pump (11) preferably generates négative pressure or the device is operated at high altitudes in order to lower the boiling température.

The containers of the distillation assembly may also deviate from the circular cross-section and exhibit, for example, an oval, elliptical, triangular or polygonal cross-section. The surface may be cornigated and/or bear ribs in order to improve heat transfer and increase the évaporation and condensation surface.

The invention (Figs. 8 and 9) can be improved by surrounding the distillation assembly (1) with a double-walled tube (13) which is evacuated similar to a thermos flask and where at least the outer tube (14) is translucent. In variant A ofthe invention, both tubes (14, 15) must be translucent. In variant B and C of the invention, the outer tube (14) must be translucent and the inner tube can be translucent ( 15) or coated with a sunlight-absorbing layer (e.g. TiNox), in which case it serves as a container for the feed liquor (Fig. 9). If the inner tube (15)is translucent, the solar radiation absorbing layer is on the surface (16) or part ofthe surface (16) of the distillation assembly (1). The light-transmitting tubes preferably hâve layers that reduce the reflection of solar radiation (2) and reflect the infrared radiation of the distillation assembly. Outside the area where the solar radiation strikes, the double-walled tube can be mirrored similar to a Dewar vessel in order to achieve even better heat insulation there. If one or more heat exchangers (17) are provided, which allow the feed liquor to flow in as hot as possible, then it is essential that thermally, they are well insulated from the surroundings. Heat exchangers ( 17) are particularly efficient in terms of their insulation if they are located within the double-walled evacuated tube, above and/or below the containers for the feed liquor and distillate. In addition, one or more Peltier elements may also be provided in the heat exchangers in order to supply electrical current for operating the device in accordance with the invention by means of the Seebeck effect.

Corrosion-résistant metals and/or plastics ai e preferably used as a material for the distillation assembly. These can also be surface-treated in order to prevent distortion when boiling and/or to promote condensation. Plastics are not as thermally conductive as metals. However, if a double-walled evacuated outer tube is used, the distillation assembly is thermally insulated from the environment to a large extent, and a higher température gradient does not significantly reduce the efficiency. Plastics hâve the advantage that they are cheaper and lighter than metals.

A décisive advantage of the invention is that the distillator has a large diameter compared to other solar Systems that focus the sun's rays much more on thinner tubes in which a liquid flows that dissipâtes the heat. The distillation assembly (1) even nee ls a larger diameter, because otherwise the boiling feed liquor (4) would splash out of the container (3) for the feed liquor due to the vapour that is produced.

Due to the large diameter, only a smaller focus is needed compared to solar Systems that use thinner pipes and carry out the distillation in a way that is spatially separated.

This means that the parabolic trough mirroi does not hâve to hâve an exact parabolic shape and that inflatable, foldable, expandable or collapsible mirrors can also be used.

If a tower with many mirrors is used, fiat mirrors with the approximate width of the diameter of the tower or inflatable, foldable, expandable or collapsible mirrors can also be used. Due to the comparatively large diameter of the distillai ion assembly, filters, e.g. activated carbon filters, microfilters, ultrafilters and/or nanofïlters, can also be installed directly in the distillation assembly to remove or reduce unwanted impurities which are présent in the vapour of the feed liquor.

The compresser (7) used to compress the steam can be a flow compresser, e.g. an axial, radial or diagonal turbo compresser, a positive displacement compressor, e.g. a rotary compresser, a Roots compresser or a screw compressor, a fan or a centrifugal blower. The compressor is driven by a motor, e.g. an electric motor or a Stirling motor, or by a turbo motor, e.g. an axial, radial or diagonal turbine, or by positive displacement motor, e.g. a rotary piston machine, driven by the vapour of the feed liquor. A turbine driven by the vapour of the feed liquor may also drive a generator, the electric current of which then drives the motor of the compressor and is available for further applications, e.g. miiTor control, pump operation and valve control. If the compressor (7) is driven by a turbine, a generator can also be driven, which is then available for further applications, e.g. mirror control, pump operation and valve control. This can also be used as a motor, whereby the output of the turbine can be varied by a throttle valve, a waste gâte or by changing 1he geometry. The compressor (7) and, if provided, the turbine may also be executed as multiple units and made of plastic or partly of plastic in order to save production costs. Excess electrical power can be supplied to the feed liquor via heating éléments. A gearbox can also be arranged between ail units to adjust speeds. If a motor is provided, the unit can ^Iso be operated with négative pressure.

Fig. 10 shows the device (1) in accordance with the invention with an electronic regulator (18) and/or control or signal lines (19). In the container (3) for the feed liquor there is a level indicator (20) which prevents feed liquor from entering the compressor by means of a level regulator. When liquids are evaporated, gas bubbles are formed which are capable of splashing the liquid. The vapour flow can then transport the liquid droplets further. If necessary, these droplets are intercepted by a splash guard (21 ), e.g. a labyrinth, sieve and/or wire mesh, through which the vapour flows, before they enter the compressor. The level regulator Controls one or more pumps (22) that deliver the output liquid (4) to the ^Q feed liquor container (3) and/or one or more valves (23) that control the outflow of the feed liquor (distillation residue). The level regulator is intended to ensure that no liquid enters the splash guard, an optional filter (24) and/or the compressor and that the distillation residue remains liquid so that it can flow out of the distillation assembly (1). There is a level indicator (25) in the container (5) for the distillate (6) which, on the one hand, prevents vapour from escaping from the compressor by means of a level regulator, and on the other hand prevents the level of the distillate from remaining as low as possible so that there is the greatest possible surface area for the condensation of the vapour. For this purpose, one or more valves (26) are controlled in the discharge line or lines so that the level of the liquid distillate is above ail the discharge lines. Ail pumps çan be replaced by a container placed above the distillation assembly from which, with the help of gravity and one or more control valves, the feed liquor is fed to the distillation assembly or several distillation assemblies. Each valve can also be replaced by a pump, e.g. a gear pump or peristaltic pump, which pumps liquids in a well-dosed manner. The measurement of the level in both containers can be donc e.g. with a float, by measuring the electrical conductivity, by measuring capacity, by optical measurement, by ultrasoniç measurement or by measurement with microwaves or radar. The level régulation can be mechanical and/or electronic. Pressure régulation can be performed through the power of the drive of the compresser (7). If there is a turbine to drive the compresser, the pressure control can bç varied by the power of the turbine through a throttle valve, a waste gâte or by changing the geometry.

If a fîlter (24) is installed in the turbine, it is necessary to take into account that a pressure drop will occur in the filter. Excess pressure can be discharged by one or more relief valves or reduced by swinging out the mirror.

In addition, there may be further feed and discharge lines through which cleaning, disinfection and/or rinsing liquids are fed to the distillation assembly. During distillation, scale can form in the containers and in the feed and discharge lines (sealing). Furthermore, biological contamination as a resuit of organisms can lead to a problem (fouling). Cleaning, disinfecting and/or rinsing can help to get both under control. The surfaces of the containers can be coated with sealing and fouling-repellent layers (e.g. Teflon) or nanotechnologically treated (e.g. carbon nanotubes). The coatings can also improve the corrosion behaviour of the container materials. Furthermore, it is possible to use physiçal methods for cleaning, such as ultrasound and/or vibrations, by using appropriate sound generators, e.g. piezo crystals and/or vibrator devices in the distillation assembly and at the inlet and outlet pipes. For large installations, preferably solar towers, a so-called pig can be used. This is a device used in pipelines that moves through tubes or tubular containers and checks and cleans the walls. In the case of the device in accordance with the invention, its movement is carried out e.g. via ropes and/or toothed racks.

Photovoltaic cells can be found on the solar radiation absorbing layer, the electricity from which can be used to drive the compressor and/or is available for other applications, e.g. mirror control, pump operation and valve control. The advantage of this arrangement is that the efficiency of the photovoltaiç cells plays an insignificant rôle, because the waste heat from the photovoltaic cells can be used to evaporate the feed liquor. When the solar radiation is concentrated by mirrors, the photovoltaic cells operate at high températures, reducing their efficiency. However, efficiency is increased due to the concentrated sunlight. As an option, photox oltaic cells may also be mounted at other locations on the device in accordance with the invention.

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In ail three variants, the distillation assembly (1) can be installed or erected in different ways. These designs are shown in Figs. 11, 12, 13 and 14 and are designed as CSP (concentrated solar power) plants.

The distillation assembly (1) is inclined and oriented substantially normal towards the solar radiation (Figs. 11 and 12). A parabolic trough mirror (27), in the focal line of which the distillation assembly (1) is located, is rotatably mounted. The arrangement of the distillation assembly (1) and parabolic trough mirror (27) is held in position by a frame (28), wherein part of this frame (28) is preferably formed by a tube (29) in the shape of a D and this tube is optionally rotated along with the parabolic trough mirror. In particular, if the compresser of the distillation assembly is driven by a turbine by the vapour of the feed liquor, this vapour can be directed into the tube (29) and condensed there so that this distillate additionally accumulâtes there. A condenser can be located in the pipe (29) if the vapour from the turbine does not condense entirely on tlte pipe walls. The condenser can bç cooled with the feed liquor or other liquids. The distillate from the distillation assembly can optionally also be collected in the pipe. The parabolic trough mirror (27) is automatically or manually adjusted by a drive so that the reflected and focussed solar radiation (2) fells on the distillation assembly (1). Furthermore, the élévation angle ofthe distillation assembly (1) and the parabolic trough mirror (27) can be changed depending on the position of the sun during the day. This design is particularly suitable for dismountable and portable designs with optional manual tracking of the mirror. For this purpose, the device in accordance with the invention is constructed in a modular manner. The modulai' components are, for example, the distillation assembly (1), the mirror (27), the tube (29) in D shape and the frame (28). The mirror (27) can additionally be designed to be foldable, expandable and/or inflatable. The tube (29) can be further separated, e.g. to allow clearing. The frame (28) and the other modules are preferably held together by screw fasteners and/or quick-release fasteners. Due to the inclined arrangement of the distillation assembly, this design is unsuitable for équatorial latitudes.

The distillation assembly (1) is arranged either horizontally, sloping southwards in the northem hemisphere of the earth, or sloping northwards in the southem hemisphere of the earth, in a north-south direction (Fig. 13). A parabolic trough min or (27), in which the centre of the distillation assembly ( l ) and/or the container (3) for the feed liquor is located in its focal line, is rotatably mounted. The distillation assembly is curved upwards at one end (30) so that the feed liquor and the distillate do not flow into the compressor or turbine and is curved downwards at the other end (31) so that the distillate can be tapped there. The end (30) of the distillation assembly in which the compressor is located, which is in the north in the northem hemisphere and in the south in the southem hemisphere, is preferably placed in an elevated position so that the vapour in the distillation assembly can escape more easily and the solar radiation strikes the distillation assembly (1) more intensively than in a horizontal arrangement.

The tracking is carried out automatically by a drive depending on the time of day so that the reflected and focussed solar radiation (2) falls on the distillation assembly (1) and/or on the container (3) for the feed liquor. This designl 1 is also suitable for équatorial latitudes and is suitable for a solar farm power plant with a large number of distillation assemblies.

The distillation assembîy (1) is erected as a solar tower (32) and surrounded by mirrors (33) (Fig. 14) which direct the sunlight onto the solar tower (32), wherein each min-or (33) must be aligned according to the time of day and season for this purpose. The solar radiation (2) is preferably directed as uniformly as possible through these mirrors (33) onto the tower-shaped distillation assembîy. Depending on the topography of the installation site, it may be necessary to place the distillation assembîy on a platform • (34) so that it can be illuminated along its entire length. The mirrors (33) are preferably designed as rectangular because the tower-shaped distillation assembîy preferably has an elongated shape.

In contrast to other tower-shaped solar Systems, the solar radiation is not directed to a point but to a line. This means that the températures and requirements of the materials are less and birds flying near the tower (32) are exposed to less danger.

The device in accordance with the invention is also suitable for being executed as an oft-shore installation in a body of water. The device in accordance with the invention or parts ofthe device in accordance with the invention may be floaling, in which case they are either anchored to the bottom of the body of water and/or hâve their own propulsion to maintain position. The device in accordance with the invention or parts of the device in accordance with invention can also be located at the bottom of the body of water and extend above the surface of the water by means of a tower and/or a foundation, in which case several or ail of the parts can also be mounted on one or more platforms. If a paraboliç trough mirror (27) is used, the entire device is located in the body of water, although installation in a tidal zone is also possible. When using a tower (32), the tower (32) and the mirrors (33) can be located in water and/or in a tidal area. However, the tower (32) can also be on land and ail, or some of the mirrors (33) can be in the water. Conversely, the tower (32) can be in water and/or a tidal area and in addition, several or ail mirrors (33) can be on land.

The invention will be explained in more detail using spécifie examples.

Fig. 15 shows variant A as a cross-section along the central axis with a radial compresser turbine (35), wherein the vapour (36, small arrows) is compressed from the inside to the outside (outflow) and fed into the area above (37) and below (38) the compresser. Above the compresser (35) there is a radial turbine (39) which is driven by the vapour (36, small arrows) and which drives the compresser (35) via an axle (40), wherein the vapour (36, small arrows) flows from the outside to the inside (inflow). It is also possible to only direct the compressed vapour into the area below (38) the compresser and to drive the turbine (39) directly with the vapour from the container (5) of the feed liquor, wherein, for example, the axle (40) is made from hollow material so that this vapour can reach the area above (37) the compresser in order to drive the turbine (39). However, the vapour can also be directed sideways past the compresser via pipe connections. The compressed vapour condenses on the outer surface of the inner container (3). The arrangement is, for the most part, rotationally symmetrical, with the exception

of the feed and discharge lines for the liquids. The feed liquor is fed into the central container by a pump and discharged via a valve. The distillate collects in the outer container and is discharged via a valve.

Fig. 16 shows variant B as a cross-section along the central axis with an axial compressor turbine (41). Above the compresser (41), there is a radial turbine (39) which is driven by the vapour (36, small arrows) and which drives the compressor (41) via an axle (40), wherein the vapour (36, small arrows) flows from the outside to the inside (inflow). The compressed vapour condenses on the inner surface of the inner container (5). The arrangemeni is largely rotationally symmetrical, except for the feed and discharge lines of the liquids. The feed liquor is fed into the outer container by a pump and discharged via a valve. The distillate collects in the middle container and is discharged via a valve.

Fig. 17 shows variant C as a cross-section along the central axis with a Roots compressor (42).

Fig. 18 shows this variant in as cross-section through the Roots compressor (42) normal to the central axis. The Roots compressor (42), which is driven by an electric motor (43), compresses the vapour (36, small arrows) from the left-hand container, which contains the feed liquor, into the right-hand container. The compressed vapour condenses on the separating surface (12) of the two containers. The feed liquor is fed into the left-hand container by a pump and discharged via a valve. The distillate collects in the right container and is discharged via a valve.

Ail designs of the distillation assembly (1) shown in Fig. 15, 16, 17 and 18 can be irradiated directly by a parabolic trough mirror, in the focal line of which the distillator is located, or by sunlight through a plurality of mirrors, in which case the distillation assembly is erected as a solar tower (32) and surrounded by these mirrors (33).

The tracking of the mirror(s) can be computer-controlled, because the position of the sun is well-defmed at any time at any place on earth. Altematively it can be carried out by photocells which, for example, find the brightest point in the sky, by forming shadows. In the event of hail or other severe weather, the mirror can be controlled to act as a shield for the distillation assembly. Using the invention, it is possible to erect large installations, e.g. by using the design with a horizontal distillation assembly arranged in multiple rows or by making the tower design correspondingly large and constructed with many mirrors. If necessary, multiple distillation assemblies are also possible with the invention, e.g. for the production of bioethanol, by arranging distillators one behind the other and using the respective distillation residue as the feed liquor for the next distillation assembly. In the case of seawater desalination, it is possible to conduct the resulting distillation residue, the brine, into évaporation basins in order to obtain sait.

Finally, an explanation is given as to how boiling delay can be reduced and/or prevented.

Boiling distortion often occurs in distillation processes. In order to prevent scale and biological deposits which promote boiling delay, smooth surfaces are required in the container (3) of the feed liquor (4), especially in the case of sait water desalination. Boiling distortion is particularly unfavourable in tubular containers, because the sudden uncontrolled boiling can cause the feed liquor (4) to splash and contaminate the system and/or the distillate. One way to avoid this is to use boiling stones and/or one or more boiling rods placed in the feed liquor container (3). Furthermore, agitators that stir the feed liquor (4) hâve proven their worth. Boiling distortion can also be prevented by introducing air, gas or vapour into the feed liquor (4) and/or by optionally fusing quartz grit on the top or partial top surface of the container (3) for thç feed liquor (4) made from quartz glass.

Another method is to expose the feed liquor container (3) to ultrasound, which not only prevents boiling distortion but also counteracts scale and biological deposits. In addition, the distillate can be physically treated in order to treat the germs, e.g. by means of radiation stérilisation with UV light, using mercury vapour lamps, light-emitting diodes, lasers and/or gas discharge lamps, preferably arranged in the distillate container. As an option, pressure and température sensors are installed in the device according to the invention, the measurement signal of which is preferably transmitted onwards to the electronic regulator (18) in order to be able to control the boiling of the feed liquor (4) more accurately.

Claims (15)

1. Patent claims

   1. The invention relates to a distillation assembly ( 1 ) which, with the aid of solar energy (2), continuously evaporates a feed liquor (4), characterised in that one or more containers (3) containing the feed liquor and one or more containers (5) in which the distillate collects are part of a distillation assembly, wherein these containers (3, 5) are in thermal contact and one or more compressors (7) compresses the vapour, which is produced as a resuit of boiling the feed liquor (4) by concentrating solar energy (2) and/or by négative pressure, into the distillate container (5) so that this vapour condenses there and the vaporisation enthalpy and thermal energy are returned to the feed liquor (4) via the thermal contact, wherein these containers (3, 5) hâve a circulai' crosssection or a cross-section deviating thereof, e.g. an oval, elliptical, triangular or polygonal crosssection, and their surface is optionally corrugated and/or bears ribs in order to improve the heat transfer and to increase the évaporation and condensation surface, and in that there is one or more feed lines (8) and one or more discharge lines (9) for the feed liquor (4) and one and more discharge lines (10) for the distillate (6), wherein the feed and discharge is preferably controlled by valves (23, 26) and/or pumps (22) and there is optionally one or more vacuum pumps (11) which generate négative pressure in the one or more containers (3) which contain the feed liquor (4), and/or the distillation assembly (1) is operated at high altitudes in order to lower the boiling température of the feed liquor (4).
2. 2. The device in accordance with claim 1, characterised in that the container or containers (3) containing the feed liquor (4) are located in a container or containers (5) containing the distillate (6) and the vapour, wherein the containers (3, 5) are in thermal contact, wherein the vapour is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and compressed by a compressor or compressors (7) so that it condenses on the walls of the distillate container (5) and releases the inhérent thermal enthalpy of the vaporisation and thermal energy to the feed liquor container or containers (3) in order to retum the heat to the feed liquor (4) wherein the light from the sun (2) pénétrâtes the outer container or containers (5) which contain the compressed vapour, the walls of which are designed to be transparent to solar radiation.
3. 3. The device in accordance with claim 1, characterised in that the container or containers (5) containing the distillate (6) and the vapour are located in the container or containers (3) containing the feed liquor (4), wherein the containers (3, 5) are in thermal contact, wherein the vapour is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and compressed by a compressor or compressors (7) so that it condenses on the walls of the distillate container (5) and releases the inhérent thermal enthalpy of vaporisation and thermal energy to the feed liquor container or containers (3) in order to retum the heat to the feed liquor (4) wherein the light from the sun (2) strikes the outer container or containers (3) which contain the feed liquor.
4. 4. The device in accordance with claim 1, characterised in that one or more containers (3) containing the feed liquor (4) is in thermal contact, via one or more membranes and/or contact surfaces (12) with one or more containers (5) containing the distillate (6) and the vapour, wherein the vapour is produced by the évaporation of the feed liquor (4) with the aid of the energy of sunlight (2) and compressed by one or more compressors (7) so that it condenses on the walls of the membrane or contact surface (12) and releases the inhérent thermal enthalpy of vaporisation and thermal energy to the one or more feed liquor containers (3) in order to return the heat to the feed liquor (4), wherein, the radiation from the sun (2) strikes the one or more feed liquor containers, and the distillation assembly (1) can be turned so that, if possible, only the one or more feed liquor containers are illuminated, or it can strike both types of containers (3, 5), in which case the solar energy is transferred to the one or more feed liquor containers by' heat conduction.
5. 5. The device in accordance with any one of the preceeding claims, characterised in that the solar energy' (2) is transmitted by means of one or more mirrors such as parabolic trough mirrors (27) and/or Fresnel mirrors, wherein these mirrors are optionally also designed as inflatable, foldable, expandable or collapsible mirrors, with one or more Fresnel lenses and/or transmitted onto the distillation assembly (1) by a plurality of mirrors (33) and these mirrors and lenses are preferably tracked according to the illumination conditions, wherein the tracking of the mirror or mirrors is computer-controlled because the positon of the sun is well-defîned at every place on earth at any time, or by photocells which find the brightest area in the sky, and these mirrors can be optionally rotated into a safe position in the event of storms, and in that the device in accordance with the invention or parts of the device in accordance with the invention are arranged as floating parts with barks on a body of water, in which case they are either anchored to the bottom of the body' of water and/or hâve their own drive in order te maintain the position, and/or the device in accordance with the invention or parts of the device in accordance with the invention stand on the bottom of a body of water or a tidal area or are held above the surface of the water with a tower or a foundation, in which case, several or ail of the parts are optionally mounted together.
6. 6. The device in accordance with any one of the preceeding claims, characterised in that the containers, compressors, pipes and/or optionally available vacuum pumps, turbines, pumps, and/or valves of the device in accordance with the invention are preferably made of corrosion-résistant metals and/or plastics, wherein these materials are optionally coated, e.g. with Teflon, and/or nanotechnologically treated, e.g. with carbon nanotubes, in order to prevent or reduce scale and/or biological contamination by organisms, and/or these materials are optionally' surface-treated and/or coated in order to prevent boiling distortion and/or to promote condensation, and in that a splash guard (21), e.g. a labyrinth, a sieve and/or a wire mesh, and/or one or more filters (24), e.g. an activated carbon filter, microfilter, ultrafilter and/or nanofilter, are installed in the container (3) of the feed liquor (4) which remove or reduce undesirable impurities which are present in the vapour

   ofthe feed liquor, and in that optional other feed and discharge lines are available through which cleaning, disinfecting and/or rinsing liquids are fed to the distillation assembly (1), and/or in that °O physical methods for cleaning are optionally used, such as ultrasound and/or vibration devices, and in that corresponding sound generators, e.g. piezo crystals and/or vibrator devices are installed in the distillation assembly (1) and at the inlet and outlet pipes, wherein one or more pigs, a device which is used in pipelines and which moves through tubes or tubular containers and checks and cleans the walls, are accomodated within the device in accordance with the invention and wherein its movement is preferably effected via ropes and/or toothed racks.
7. 7. The device in accordance with any one of the preceeding claims, characterised in that thç feed liquor (4) is supplied (8) and discharged (9) and the supply and discharge quantities are controlled so that the level of the feed liquor (4) temains within a certain range so that no liquid enters the optional splash guard (21), an optionally installed filter (24) and/or into thç compressor(s) (7), and in that the feed liquor maintains a liquid consistency, and in that the distillate (6) is continuously discharged (10) and the discharge quantity is controlled in such a way that the level of the distillate is above the discharge line or lines (10) so that no vapour can escape, and preferably remains as low as possible so that there is the greatest possible surface area for the condensation ofthe vapour, wherein the régulation of the flow quantity of the liquids (4, 6) that are suppliçd and discharged is carried out manually or automatically, e.g. electronically and/or mechanically, and preferably, sensors (20, 25) are installed which transmit the level to the level regulator (18) in order to generale a control signal for valves and/or pumps (22, 23, 26) and/or optionally, sight glasses are installed in order to make the level or levels of the liquids (4, 6) visible.
8. 8. The device in accordance with any one of the previous claims, characterised in that optionally, instead of one or more pumps (22), one or more containers are arranged above the distillation assembly (1) from which the feed liquor is supplied to the distillation assembly (1) in accordance with the invention or several distillation assemblies in accordance with the invention with the aid of gravity and preferably, via one or more control valves, and in that, optionally, instead of one or more valves (23, 26), one or more pumps, e.g. gear pumps or hose pumps, are installed, which pump liquids in a well-dosed manner, and in that the level indicator (20, 25) for the feed liquor (4) and the distillate (6) is preferably carried out by means of one or more control valves and in that, optionally, instead of one or more valves (23, 26), one or more pumps, e.g. gear pumps or peristaltic pumps are installed which supply liquids in a well-dosed manner, and in that the level indicator (20, 25) for the feed liquor (4) and the distillate (6) is carried out preferably by means of a float, by measuring the electrical conductivity, by measuring capacity, by optical measurement, by ultrasonic measurement or by measurements using microwaves or radar, and in that the pressure is controlled by the power of the drive of the compresser or compressors (7) and/or in that excess pressure is discharged by one or more excess pressure valves and/or is reduced by swinging out the mirror.
9. 9. The device in accordance with any one of the previous claims, characterised in that the distillation assembly (1) is located in a double-walled evacuated tube (13) or serves as a container in a doublewalled evacuated tube (13) and is e.g. made of borosilicate glass, wherein the outer tube (14) is translucent, the inner tube (15) is translucent and then optionally serves as a container (5) for the distillate or is light absorbing by being coated with a solar radiation absorbing layer (e.g. TiNox) and then serves as a container (3) for the feed liquor and wherein said translucent tubes preferably hâve layers which reduce the reflection of the solar radiation (2) and reflect the infrared radiation of the distillation assembly, and wherein outside the area which is struck by the solar radiation the double-walled tube (13) is preferably miiTored similar to a Dewar vessel in order to achieve even better thermal insulation there.
10. 10. The device according to one of the previous claims, characterised in that the compresser or compressors (7) serving to compress the vapour is/are designed as a flow compresser, e.g. axial, radial or diagonal turbo compresser, as a displacement compresser, e.g. rotary compresser, Roots compresser or screw compresser, as a fan or as a centrifugal blower, wherein this or these compressors (7) are driven by a motor, e.g. by an electric motor (43), by a Stirling motor, by a turbo motor driven by the vapour of the output liquid, e.g. an axial, radial (39) or diagonal (39) motor. e.g. by an electriç motor (43), by a Stirling engine, by a turbo motor driven by the vapour of the feed liquor, e.g. an axial, radial (39) or diagonal turbine, or by a turbo motor driven by the vapour of the feed liquor, e.g. a rotary piston motor, wherein in the case of the compressor or compressors (7) being driven by means of turbo motors or by means of displacement motors, the vapour of the feed liquor required for this purpose is optionally supplied to the turbo engine or engines or to the displacement motor or motor by means of pipes and/or by means of the then hollow drive axle (40), wherein the power of this motor or these motors is optionally varied by means of a throttle valve, a waste gâte or by means of a change in geometry, and said vapour is optionally condensed in order to obtain additional distillate, and in addition, optionally, said motors(s) each drive an electric generator in order to be independent of the public power grid, and said generator(s) are also optionally used as a motor, and if the compressor(s) (7) is/are driven by only one electric motor (43) respectively, the flow motors or the displacement motors optionally each drive a generator in order to be independent of the public power grid, and in that ail devices and/or combinations of devices may optionally be repeated as mutiple units and a gearbox is optionally arranged between ail devices in order to adjust speeds.
11. 11. The device in accordance with any one of the preceding claims, characterised in that one or more heat exchangers (17) are installed in the feed and discharge lines (8, 9, 10), which allow the feed liquor to flow in as hot as possible by supplying the heat of the outflowing distillation residue (9) and/or the outflowing distillate (10) to the feed feed liquid (8), wherein, if there is a double-walled evacuated tube (13), the heat exchangers (17) are preferably located therein so that the thermal insulation is improved, wherein as an option, one or more Peltier éléments are arranged in and/or on the heat exchangers (17) which, with the aid of the Seebeck effect, supply electric current in order to operate the device according to the invention and/or in that photovoltaic cells are arranged on the solar radiation absorbing layer and/or at any location, the electric current of which is independent of the public electric grid optionally drives the compressor or compressors (7) by means of an electric motor (43) and/or is available for f'urtl er applications, e.g. controlling the mirror, pump operation and valve control, wherein the lost heat from the photocells and/or the heat generated with excess electrical energy is optionally fed back: to the feed liquor.
12. 12. The device according to any one of claims 1 to 11, characterised in that the distillation assemby (1) is inclined and oriented substantially normal to the solar radiation (2), with a parabolic trough mirror (27) in the focal line of which the distillation assembly (1) is located, wherein the distillation assembly of (1) and parabolic trough mirror (27) are held in position by a frame (28), a part of this Trame (28) is preferably formed by a tube (29) in a D shape and the rotatably mounted parabolic trough mirror or the rotatably mounted tube is aligned with the fixed parabolic trough mirror according to the light conditions, and, if the compressor or compressors (7) of the distillation assembly with one or more turbines are operated by the vapour of the feed liquor, this vapour is preferably conducted into the tube (29) and condenses there, optionally with the aid of an additional condenser located in the tube, so that the distillate thereby produced accumulâtes in the tube, and in that optionally, the angle of élévation of the distillation assembly (1) and of the parabolic trough min-or (27) is changed depending on the position of the sun in the course of the day with the aid of a rotatable bearing and a drive, and in that the device in accordance with the invention is optionally constructed in a modular manner and that these modules are preferably held together by screw fasteners and/or quick-action fasteners, the modular components being, for example, the distillation assembly (1), the mirror (27), the tube (29) in a D shape and the frame (28), wherein the tube (29) can be further separated, in order, for example, to allow cleaning and in that in accordance with the invention, devices of this type, are optionally operated in parallel in farms and/or are arranged in sériés, wherein the respective distillation residue is used as the feed liquor for the next distillation assembly, and in the case of seawater desalination the resulting distillation residue, the brine, is optionally fed into évaporation basins in order to obtain sait.
13. 13. The device according to any one of claims 1 to 11, characterised in that the distillation assemby (1) is arranged either horizontally or slightly in a sloping direction, substantially in a north-south direction, with one or more rotatably mounted parabolic trough mirrors (27), in the focal line of which the centre of the distillation assembly (1) or the container (3) for the feed liquor is located, wherein the distillation assembly is bent upwards at one end (30) so that the feed liquor and the distillate do not flow into the compressor and/or into the turbine, respectively, and are bent downwards at the other end (31) so that the distillate can be tapped thereand wherein the end (30) of the distillation assembly in which the compressor is located is preferably arranged in a slightly elevated fashion so that the vapour in the distillation assembly can escape more easily and in that by means of a drive, the tracking is carried out automatically depending on the time of day in such a way that the reflected and focused solar radiation (2) is directed onto the distillation assembly (1) or onto the container or containers (3) for the feed liquid, and in that in accordance with the invention, devices of this type are optionally operated in paraiiel in farms and/or are optionally arranged one behind the other, wherein the respective distillation residue is used as the feed liquor for the next distillator, and, in the case of seawater desalination, the resulting distillation residue, the brine, is optionally passed into évaporation basins in order to obtain sait.
14. 14. The device according to any one of claims 1 to 11, characterised in that the distillation assembly (1) is erected vertically as a solar tower (32) and is surrounded by mirrors (33) which direct the sunlight (2) onto the solar tower (32), wherein each mirror (33) is preferably rectangular, being aligned for this purpose according to the time of day and the season, or with respect to the brightest point in the sky so that the solar radiation (2) is directed onto the tower-shaped distillation assembly (32) or onto the container or containers (3) for the feed liquor and is preferably distributed there as uniformly as possible, and in that the solar tower (32) optionally stands on a platform (34) so that it can optionally be illuminated over its entire length, and in that devices of this type according to the invention are optionally operated in paraiiel and/or are arranged one behind the other wherein the respective distillation residue is used as the feed liquor for the next distillation liquor, and in the case of seawater desalination, the resulting distillation residue, the brine, is optionally fed into évaporation basins in order to obtain sait.
15. 15. The device according to any one of the previous claims, characterised in that boiling stones and/or one or more boiling rods are placed in the feed liquor container(s) (3), and in that one or more agitators stir the feed liquor (4), and in that air, gas and/or steam is/are fed into the feed liquor (4), and in that the container or containers (3) for the feed liquor (4) are made of quartz glass, on the top or partial surface of which quartz grit is optionally fused, and in that the feed liquor container or containers (3) is and/or are exposed to ultrasound in order to prevent boiling distortion, wherein the ultrasound is also able to counteract scale and biological deposits, and in that the distillate is physically treated to kill germs, e.g. through the use of radiation stérilisation with UV light, mercury vapour lamps, light-emitting diodes, lasers and/or gas discharge lamps, which are preferably arranged in the distillate container or containers and/or in that pressure and température sensors are installed in the device in accordance with the invention, the measurement signal of which is preferably passed on to the electronic regulator (18) in order to be able to control the boiling of the feed liquor (4) more accurately.