Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/0064—Feeding of liquid into an evaporator
  • B01D1/007—Feeding of liquid into an evaporator the liquid feed being split up in at least two streams before entering the evaporator
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/0011—Heating features
  • B01D1/0041—Use of fluids
  • B01D1/0047—Use of fluids in a closed circuit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
  • B01D1/221—Composite plate evaporators
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/30—Accessories for evaporators ; Constructional details thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
  • B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
  • B01D3/343—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances the substance being a gas
  • B01D3/346—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances the substance being a gas the gas being used for removing vapours, e.g. transport gas
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/02—Treatment of water, waste water, or sewage by heating
  • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/02—Treatment of water, waste water, or sewage by heating
  • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
  • C02F1/14—Treatment of water, waste water, or sewage by heating by distillation or evaporation using solar energy
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/08—Seawater, e.g. for desalination
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/124—Water desalination
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/124—Water desalination
  • Y02A20/138—Water desalination using renewable energy
  • Y02A20/142—Solar thermal; Photovoltaics
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/20—Controlling water pollution; Waste water treatment
  • Y02A20/208—Off-grid powered water treatment
  • Y02A20/211—Solar-powered water purification
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/20—Controlling water pollution; Waste water treatment
  • Y02A20/208—Off-grid powered water treatment
  • Y02A20/212—Solar-powered wastewater sewage treatment, e.g. spray evaporation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
  • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Definitions

• the present invention due to the collaboration of Jean-Paul DOMEN and Stéphane VIANNAY, relates to improvements to an earlier invention of the first named, relating to distillation processes and apparatus, described in a PCT international patent application, filed by applicant and published on December 20, 2001 under No. WO 01/96244 A1.
• This PCT application describes a general multiple-effect distillation process intended to separate solids in solution from their liquid solvent, as well as two particular processes and stills.
• distillation processes and devices are mainly intended to produce fresh water, easily transformable into drinking water. They use low-temperature hot springs of various types (standard boiler, solar boiler or heat engine radiator) and they treat most non-potable water, such as seawater, brackish groundwater or water clear but polluted surfaces. To this main application, there are those concerning the production of concentrates in various industries, in particular food or chemical.
• S 0 and Sf are faces of walls of thin hollow distillation heat exchange plates, installed in large numbers, vertical or inclined, in a heat-insulated treatment chamber, comprising narrow inter-plate spaces, of substantially width constant, filled with an incondensable gas, in particular air at atmospheric pressure; - the heat transfer fluid flows from top to bottom along the surfaces Sc, passing from a high initial temperature Ti to a final temperature T3 lower than Ti, then from bottom to top along the surfaces Sf, passing from a temperature initial TA, lower than T3, at a final temperature T2, higher than T4 and lower than Ti;
• a hot source is arranged between the hottest ends of the surfaces Sc and Sf, to increase the temperature of the heat transfer fluid from T2 to Ti;
• a cold source is disposed between the less hot ends of these surfaces S 0 and St, to lower the temperature of the heat transfer fluid from T3 to T4.
• the heat transfer fluid is the liquid to be distilled
• the heat transfer liquid circulates from top to bottom inside the hot plates, it enters hot at temperature Ti and it comes out cooled at temperature T3, after having caused a partial evaporation of the liquid to be distilled in flow on the faces external of these plates; -at the outlet from the hot plates, the heat transfer liquid undergoes additional cooling and goes to temperature T4;
• this heat transfer liquid at temperature T4 enters the interior of the cold plates where it circulates from bottom to top, on the one hand, causing, on the external faces of the walls of these cold plates, a condensation of the vapor. diffused through the incondensable gas plate of the inter-plate space and, on the other hand, by recovering part of the heat of condensation of this vapor to heat up and finally it leaves the cold plates at temperature T2;
• the distilled liquid descends along the external faces of the walls of the cold plates while the concentrated liquid descends along the external faces of the walls of the hot plates.
• the heat transfer fluid is said noncondensable gas, saturated with vapor of the liquid to be distilled;
• the gas stream at temperature Ti enters inside all the hollow plates where it circulates from top to bottom, while part of its vapor condenses on the internal faces of the walls of the plates, only heat flows , due to a partial recovery of the heat of condensation, pass through the walls of the plates to evaporate part of the flowing liquid on their external faces and that, as a result, this stream of gas cools and leaves the hollow plates at the temperature T3;
• this gas stream at temperature T4 enters the inter-plate spaces where it circulates from bottom to top, taking away the steam produced in these spaces and heating up, and finally it leaves these spaces at temperature T2;
• the distilled liquid descends along the internal faces of the walls of the hollow plates, while the concentrated liquid descends along their external faces.
• hollow and thin heat exchange elements made of polymer (in particular polypropylene), are described in this PCT application. These elements are thin hollow rectangular plates, of large dimensions (from 50 to 150 dm 2 generally), with a wall provided with a hydrophilic or wettable coating, welded and / or bonded. They are of two main types:
• This AVP solar still includes, in a processing chamber, a vertically arranged evaporator and condenser, and outside, a solar boiler, a radiator and a pump.
• the external wall of the evaporator is constantly humidified by sea water spilled on its upper edge.
• a heat transfer liquid circulates in a closed circuit from the bottom to the top of the boiler, from top to bottom of the evaporator, from bottom to top of the radiator and from bottom to top of the condenser, finally reaching bottom of the boiler.
• the radiator is a body for cooling the heat transfer liquid, subjected to the action of an air current.
• this saturated hot air rises along the walls of the evaporator, begins to circulate in a closed circuit in the treatment chamber and, during its journey, crosses from top to bottom the area occupied by the condenser.
• the heat transfer liquid which is cooled by passing through the evaporator, undergoes additional cooling by passing through the radiator. Consequently, it arrives at the bottom of the condenser at a temperature lower than that which it had on leaving the evaporator.
• the particular structure given to the condenser (see fig. 3) has the effect of circulating in cross circuits the stream of saturated hot air and the stream of cooled heat transfer liquid.
• the vapor contained in the air condenses on the relatively cold walls of the condenser and the latent heat of condensation is recovered by the heat transfer liquid, thus reducing the thermal energy required from the solar boiler. Distilled water and brine are collected in tanks respectively installed under the condenser and under the evaporator.
• the evaporator and condenser members both have complex shapes and, moreover, are different and relatively distant from each other. This hardly makes it possible to establish a high thermal conductance between them.
• the heat transfer fluid is a liquid
• the thin hollow plates are alternately hot and cold and the hot and cold currents concerned circulate at very short distance from each other and in opposite directions (and not in crossed directions), while the thin air gap separating these plates remains motionless. This makes it possible to have the particularly efficient heat exchanges which are at the origin of the high productivity of distillation sought.
• the heat transfer fluid is saturated hot air, the internal and external faces of the thin walls of the thin hollow plates constitute heat exchange surfaces, linked by a maximum thermal conductance.
• the JPD process can be subject to a mode- mathematical reading, truly representative of the phenomena concerned, which alone makes it possible to understand and therefore to optimize these phenomena, since the elements to be taken into account have simple geometry and well-defined spatial arrangements. This hardly seems to be possible with the elements of the solar still AVP, which have complex geometries and thermal connections with weak and ill-defined conductance.
• the Coefficient of Performance COP of a heat exchange or distillation apparatus that is to say the ratio between the heat power exchanged Q and the power P, supplied by the boiler, also determines the cost price of the energy exchanged and / or distilled water, via two other parameters, namely, (1) the cost of the energy used, which is inversely proportional to the COP coefficient of performance, and (2) the amortization of the price of the device, which is proportional to the Cop, as will be demonstrated below.
• a conventional counter-current heat exchanger between two fluids with a constant heat capacity C P , the following will be designated by Ti, the temperature of the heat transfer fluid, at the outlet of the boiler or at the inlet of the hot surfaces of the exchanger, by T2, the temperature of the fluid at the outlet of the cold surfaces, by T3, the temperature of the heat transfer fluid, at the outlet of the hot surfaces, and by T4, the temperature of the fluid, at the inlet of the cold surfaces of the exchanger.
• dT the temperature difference that exists on either side of the hot and cold surfaces concerned. If one neglects the heat losses of the exchanger, the two temperature differences (T3-T4) and (T1-T2) are generally both equal to dT.
• the exchanged power Q is expressed in two ways, depending on whether one considers the heat transfer fluid or the heat exchanger.
• Q kVdT, with k, the volume thermal conductance of a heat exchanger and V, the active volume of this exchanger.
• the volume thermal conductance k of a heat exchanger is defined as the thermal power in Watts, transmitted through an exchanger of one cubic meter of active volume, in response to a temperature difference of one Kelvin.
• the usage parameters are available to the user and are as follows:
• LdT appears to be a composite variable, a function both of certain construction parameters, of the extreme temperatures Ti and T3 and of all the intermediate T values. It is therefore necessary to consider t.dT as the determining independent variable, to be taken into account to calculate the temperature of the heat transfer fluid during its descent along the hot heat exchange surfaces.
• the calculation concerns the temperatures which appear from top to bottom of the hot surfaces of these plates, as a function of all the parameters concerned, namely the temperature Ti, the parameters of construction and use and the thermal conductances referred to above.
• the optimal value ranges of t.dT and T3 are defined by the curve Ai and that of QE, by its maximum (QE> 17), i.e. 1900 ⁇ tdT ⁇ 4450 Ks and 58 ⁇ T3 ⁇ 78 ° C. These ranges of optimal values vary little when the e / p ratio remains constant, the maximum of QE being all the higher as the parameters e and p have their minimum values.
• the interface through which heat transfers take place between the two water streams which circulate in opposite directions, is located in the wall which separates the current of rising water from the trickling liquid, which is the distilled water in the first case studied (circulation from top to bottom of the heat transfer liquid in the hot plates) and the brine in the second case (reverse circulation).
• this difference in thermal power is expressed by the local difference in enthalpy flow (in Watts) between the flows of saturated air along the hot external faces S 0 and cold internal faces Sf of these
• this curve C2 is clearly distinguished from the curve A2 since the increasing difference in degrees ( 0 C), which separates them from each other at each decreasing level h, expresses the local difference enthalpy flow constant dHi, which corresponds to the values of Ti and T2, expressed above. With Ti lowered to 91.5 0 C and T2 maintained at 91 0 C, the curve C2 would remain unchanged and the curve A3 obtained would be located approximately equidistant from the curves A2 and C2 shown.
• Curve B2 in FIG. 2 represents the evolution of QE as a function of the composite variable t.dH / V (in kilojoules per m 3 ) to be used in the case of a still with air flow. This change is not very sensitive to the difference (T1-T2) and therefore to the value of the local difference in enthalpy flow dHi referred to above, which was used to calculate this curve B2.
• the maximum of QE corresponds, on the curve A2, to a temperature Ti of approximately 85 ° C., at the entry of the hollow plates and, for the local deviation dHi adopted, the value of T2 read on the curve C2 is d '' about 80 ° C, at the exit of the inter-plate spaces.
• the value of Ti 1 at the entry of the hollow plates is determined by the maximum temperature of the hot source available and the value of T4, at the entry of the interplate spaces, by the minimum temperature of the natural cold source available.
• this cold source is the liquid to be distilled entering at 25 ° C.
• T3 68 ° C.
• T 4 the value of T3 increases and, in this case, the maximum of QE is lower and it is obtained for a larger t.dH / V value.
• the Intrinsic Efficiency Coefficient of the QE still defined by COP.Q / V or Q 2 / PV or k. (Ti-T3), presents a maximum of 95 m 3 of fresh water per day and per m 3 active still, for a value of the composite variable t.dH / V of 382 kiiojoules / m 3 .
• the optimal value of QE is greater than 84, which corresponds to 210 ⁇ t.dH / V ⁇ 740 kJ / m 3 and an optimal range 78 ⁇ Ti ⁇ 91 0 C.
• the first object of the present invention relates to improvements and extensions, susceptible of being brought to the general distillation process, with liquid or gaseous heat transfer fluid and with diffusion of vapor in an incondensable gas, described in said prior invention, which arise from the physical laws governing the operation of stills implementing this general process.
• the second object of the invention relates to two types of improvements, resulting from the physical laws in question, capable of being brought to particular distillation processes and apparatuses with vapor diffusion, in which the heat transfer fluid is the liquid to be distilled and the direction of circulation of this liquid, that described in said previous application or the opposite direction.
• the third object of the invention relates to two other types of improvements, resulting from the physical laws in question, capable of being brought to particular processes and apparatuses of vapor diffusion distillation, in which the heat transfer fluid is the incondensable gas, saturated in vapor of the liquid to be distilled, and the direction of circulation of this gas, that described in said previous application or the opposite direction.
• the heat transfer fluid is the incondensable gas, saturated in vapor of the liquid to be distilled, and the direction of circulation of this gas, that described in said previous application or the opposite direction.
• the fourth object of the invention relates to steam diffusion stills, in which the simple heat exchangers used have a new compact architecture, at low cost.
• the fifth object of the invention relates to a distillation heat exchanger, comprising a one-piece active element, adapted to the requirements of a still with diffusion of vapor and heat-transfer gas.
• the sixth object of the invention relates to the means for securely connecting large thin hollow distillation heat exchange plates to their inlet and outlet pipes for heat transfer fluid.
• the seventh object of the invention relates to the means of efficiently and safely spreading the liquid to be distilled on the external faces of the walls of hollow distillation heat exchange plates.
• the eighth object of the invention relates to new hollow distillation plates, thin and flexible, with very thin flat walls, usable in stills with diffusion of vapor and heat-transfer gas;
• the ninth object of the invention relates to hot springs specially adapted to the particular needs of some of the distillation apparatus referred to above.
• a general multiple-effect distillation process intended to separate from their liquid solvent matters in solution, in particular for producing fresh water or concentrates, in which:
• S 0 and Sf are faces of walls of thin hollow distillation heat exchange plates, installed in large numbers, vertical or inclined, in a heat-insulated treatment chamber, comprising narrow inter-plate spaces, of substantially width constant, filled with an incondensable gas, in particular air at atmospheric pressure; is characterized in that:
• the heat transfer fluid circulates, in a first ascending or descending direction, along the hot surfaces Sc, passing from a high initial temperature Ti to a final temperature T3 lower than Ti then, in a second direction opposite to the first, along cold surfaces Sf, passing from an initial temperature T 4 , lower than T3, to a final temperature T2, higher than T 4 and lower than Ti;
• a hot source is disposed between the hottest ends of the surfaces S 0 and Sf, to increase the temperature of the heat transfer fluid from T2 to Ti;
• a cold source is arranged between the less hot ends of these surfaces S 0 and Sf, to lower the temperature of the heat transfer fluid from T3 to T 4 ;
• a substantially constant local difference dH of enthalpy flow is established between the surfaces Sc and St, by giving amplitudes suitable for the heat exchanges respectively effected between the current of heat transfer fluid and said hot and cold sources;
• the heat transfer fluid is the liquid to be distilled
• Thin hollow distillation heat exchange plates are hot or cold and they are alternately installed in the heat-treated treatment chamber, the internal faces of their respective walls constituting said hot Sc and cold Sf surfaces;
• the heat transfer liquid circulates, in a first ascending or descending direction, inside the hot plates, it enters it very hot at the temperature Ti and it leaves it cooled at the temperature T3, after having caused a partial evaporation of the liquid at distilling in flow on the external faces of the walls of these plates;
• the heat transfer liquid at the temperature T 4 enters the interior of the cold hollow plates where it circulates in a second direction, opposite to the first, causing, on the external faces of the walls of these cold plates, a condensation of the vapor diffused through the incondensable gas plate of the interplate space and by recovering almost all the heat of condensation of this vapor to warm up, and finally it leaves cold plates at temperature T2;
• the optimum temperature Ti of the heat transfer liquid, at the inlet of the hot hollow plates, is as little as possible lower than the boiling temperature of this liquid at atmospheric pressure;
• the optimal temperature T3 of the heat transfer liquid, at the outlet of the hot hollow plates, is relatively high and located in a range which corresponds to an area surrounding the maximum of the Intrinsic Criterion of EQ Efficiency of the installation;
• T3 The interesting range of temperature T3 is the interval 58 to 78 ° C, when the liquid to be distilled is water;
• the optimal temperature difference dT is established by adjusting the ratio between the heating power of the hot source and the mass flow D of circulating heat transfer liquid;
• the optimal value chosen for dT is relatively high when the unit cost of thermal energy, readily available at the place of implementation of the process, is relatively low;
• the optimal transit time t of the heat transfer fluid in the heat exchange plates is established by adjusting the mass flow D of the heat transfer liquid circulating in a closed loop. Thanks to these provisions, the distillation process with vapor diffusion and heat transfer liquid becomes a truly efficient process, calling upon new steps which are particularly simple to implement, in application of the conclusions of the mathematical modeling of the phenomena concerned. These steps consist in significantly increasing the temperature of the liquid to be distilled entering the installation, before mixing it with the liquid to be distilled circulating in a closed loop, by a simple heat exchange with the distilled and concentrated liquids, leaving the installation at a high average temperature, close to T3.
• this value T3 is particularly high (58 to 78 ° C.), in application of the said conclusions, due to the maximum temperature Ti (100 ° C.) of the liquid leaving the boiler and the appropriate adjustment of the transit time t of the heat transfer liquid in the hollow plates, in accordance with the value chosen for the difference in temperature dT between these plates.
• this first particular vapor diffusion distillation process in which the heat transfer liquid circulates, preferably by thermosyphon, from top to bottom inside the hot hollow plates and from bottom to top inside the cold hollow plates, is further characterized in that, according to a first set of arrangements:
• a heat reheating exchange is carried out between the flow d of liquid to be distilled entering the installation at the temperature Tu and the two flows of distilled and concentrated liquids which exit therefrom, so as to bring the temperature of this flow d to a relatively high optimal intermediate value T_2;
• this first particular distillation process with vapor diffusion in which the heat transfer liquid circulates by thermosiphon, from bottom to top inside the hot hollow plates and from top to bottom inside the cold hollow plates , is characterized in that, according to a second set of arrangements, the flow rate d of liquid to be distilled entering at the temperature TLI is added to the flow rate D of heat transfer liquid leaving the temperature T3 of the hot plates, the ratio d / D being adjusted so that the mixture produced is at an optimum temperature T 4 at the inlet of the cold plates, a flow d of liquid at temperature T3 or T 4 being spread at the top of the external faces of the hot plates.
• a first and a second embodiment of the stills with vapor diffusion and heat transfer liquid circulating against the current in a closed circuit, are possible, the first however having a COP greater than that of the second, which however remains interesting, although the temperatures of the concentrated liquids Ti and distilled T2 are high, to be evacuated.
• This drawback can however be easily corrected if, by appropriate heat exchanges, this thermal energy is recovered to heat the liquid to be distilled to spread at the top of the hot plates.
• a second particular distillation process with vapor diffusion, in particular for producing fresh water in accordance with the improved general process defined above, in which:
• the heat transfer fluid is said noncondensable gas, saturated with vapor of the liquid to be distilled;
• the current of heat transfer gas at temperature Ti enters inside all the hollow distillation plates, where it circulates in a first ascending or descending direction, while part of its vapor condenses on the internal faces of the walls of the plates, that heat flows, due to a partial recovery of the latent heat of condensation, pass through the walls of the plates to evaporate part of the liquid flowing on the external faces of these walls and that, as a result, this current of gas cools and finally leaves the hollow plates at temperature T3;
• this stream of heat transfer gas at temperature T3 is cooled to temperature T 4 and the distilled liquid, condensed on this occasion, is recovered;
• this current of heat transfer gas enters the inter-plate spaces, where it circulates in a second direction, opposite to the first, by carrying the vapor produced in these spaces and by heating, and finally it leaves these spaces at temperature T2;
• the optimum temperature Ti of the saturated heat transfer gas stream, at the inlet of the hollow plates, is situated in a range which corresponds to a large area around the maximum of the Intrinsic Criteria of CIE Efficiency of the installation;
• T1-T2 the temperature difference (T1-T2) is small and the difference (T3-T4), large.
• the correspondence between the optimal range of temperatures Ti and the zone of the maximum of CIE is carried out by the intermediary of their respective relationships between a composite variable t.dH / V, in which t is the transit time in the plates, dH , a substantially constant local difference in enthalpy flow between the internal and external walls of the plates and V, the active volume of the installation; -
• the interesting range of the temperature Ti is roughly between 74 and 91 0 C;
• dH The optimal value of dH is relatively high when the cost of thermal energy, readily available at the place of use of the device, is relatively low;
• the optimal transit time t of the heat transfer gas in the heat exchange plates is established by adjusting the mass flow D of this gas. Thanks to these arrangements, the temperature T4 of the heat transfer gas, injected at the entry of the interplate spaces, (at the bottom of these spaces, in a first case or at the top in a second) is little higher than the temperature of the incoming liquid to be distilled. in the device (for example 25 ° C) and much lower than the temperature T3 of this same heat-transfer gas at the outlet of the hollow plates.
• the local difference in enthalpy flow dH, between the coolant gas streams, at variable temperature and heat capacity throughout the internal and external faces of the hollow heat exchange plates, can, over the entire height of these plates, remain substantially constant and equal (to the nearest losses) that imposed by the appropriate hot source, disposed between the exit from the inter-plate spaces and the entry of these same plates.
• the temperature differences between the streams of heat transfer gas at the outlet of the hollow plates and at the entrance of the inter-plate spaces are very different.
• this second particular distillation process is further characterized in that, according to a first set of arrangements, - the gas stream at temperature Ti is introduced at the top of the plates distillation hollows and it leaves from below at temperature T3;
• this gas stream at temperature T3 is subjected to a cooling heat exchange, provided by a cold source at the temperature Tu, constituted by the incoming flow of liquid to be distilled, so that, account - given the respective mass and thermal characteristics of this gas stream and this liquid flow rate, the temperature T3 of the gas stream is lowered to an optimal temperature T 4 and the temperature of the liquid brought to TL2;
• the gas stream at temperature T 4 is introduced at the bottom of the inter-plate spaces and it exits from above at temperature T2; - The gas stream circulates in a closed circuit in the hollow distillation plates and in the interplate spaces, under the action of at least one propellant;
• the gas stream at temperature T2 is heated and saturated with vapor, by adequate physical contact with the liquid to be distilled, heated by the hot source, so as to take an optimal temperature Ti or simply effective; - after physical contact with the gas stream at temperature T2, the liquid to be distilled is spilled, at a temperature close to Ti, at the top of the external faces of the walls of the hollow plates, and it comes out at the bottom, at a temperature close to T4;
• this second particular distillation process is further characterized in that, according to a second set of arrangements,
• this gas stream is subjected to a cooling heat exchange, provided by a cold source at the temperature TLI, constituted by the incoming flow of liquid to distilling, so that, taking into account the mass and thermal characteristics of this gas stream and this liquid flow rate, the temperature T3 of the gas stream is lowered to an optimal temperature T 4 ;
• liquid to be distilled is spilled at the top of the external faces of the walls of the hollow plates, it descends along these external faces and it leaves them at a temperature close to T2;
• the gas stream, at temperature T4 is introduced at the top of the inter-plate spaces and it exits from below at the temperature T2;
• the gas stream at temperature T2 is heated and saturated with vapor, so as to take an optimal or simply effective temperature Ti;
• the gas stream at temperature Ti is introduced at the bottom of the hollow plates and, at least by natural convection, it rises inside these plates, it then crosses an area where it undergoes said cooling heat exchange then, at temperature T 4 , it enters and descends by gravity into the inter-plate spaces;
• the liquid to be distilled which has become concentrated is collected with a view to immediate or deferred evacuation.
• the concentrated liquid to be distilled which leaves the interplate spaces, is heated by a hot source and, by adequate physical contact with this liquid thus heated, the gas stream at temperature T2 is warmed and saturated, in order to take an optimal or simply effective Ti temperature.
• the gas stream at temperature T2 is warmed and saturated, in order to take an optimal or simply effective Ti temperature.
• these auxiliary hollow plates are at the same time thin, rigid and provided with external coatings, hydrophilic or wettable;
• a boiler will be used, the heating chamber of which comprises one or more suitable heating tubes, for example immersed in or sprinkled with the liquid to be distilled, which will be traversed by an available heating fluid.
• a heating fluid may be the primary coolant of a heat engine, the exhaust gases of such an engine, the gases produced by a liquid or gaseous fuel burner, or even a thermal oil, heated during the day.
• a solar boiler with cylindrical-parabolic reflector and stored at high temperature (> 130 ° C), for day and night use, in a heat-insulated tank, at atmospheric pressure.
• a suitable solar boiler can be used during the day, to heat and supersaturate the flow of heat transfer air.
• Such a heat exchanger is particularly well suited to the needs of conventional heat exchanges that comprise the four embodiments of the present invention.
• this new type of exchanger allows, thanks to an improvement according to the present invention, to design a new architecture for a still with diffusion of vapor and heat transfer gas according to the third embodiment of the invention. This multiplies the interest and makes it possible to advantageously replace the large rectangular heat exchange plates, flexible or rigid, described in the PCT application, referred to at the beginning of this document.
• a high efficiency monobloc elementary heat exchanger limited size, reduced weight, low production cost and, generally, intrinsic inalterability, - is constituted by a single active part, in particular made of polymer, formed without assembly or welding , by a stack of pairs of elongated, hollow and thin plates, communicating and generally symmetrical;
• Each elementary conduit of the active part has two supply manifolds, the axes of which coincide with the stacking axes of the end fittings;
• each collector ends in a connection tube for the active part.
• This one-piece element of a heat exchanger can be used either as it is, when it must be installed in the unconfined current of a fluid to be heated or cooled, or enclosed in an envelope, when the two fluids concerned are confined. In both cases, the most efficient way to use such a heat exchanger is to operate it against the current.
• a method for manufacturing such a one-piece heat exchanger comprises the following steps:
• a blank of a suitable material consisting of a stack of generally biconvex bellows, relatively deep compared to the transverse dimension of the blank and comparable to those of an accordion, said bellows comprising elongated central parts, provided with end fittings, flanks, ridges and bottoms respectively having shapes adapted so that these flanks have a much greater stiffness than those of the bottoms and crests, said stack being on its side provided two connection pipes, centered on the stacking axes of said end fittings;
• this blank being at appropriate temperatures, flexibility and elasticity, apply internal depression and / or external compression forces to them, parallel to the stacking axis of the bellows, until the compressed part thus realized becomes a stack of pairs of plates hollow, communicating and generally symmetrical, with low internal thickness and spacing, substantially constant;
• this new counter-current heat exchanger for confined fluids is provided with an additional function, intended to allow good evaporation of the liquid to be distilled, in a still with diffusion of vapor and heat transfer gas.
• the outer wall of the blank of each active heat exchange element used is made hydrophilic or wettable, either by a hydrophilic coating, if necessary preformed, in the case of a polymer, or by a treatment. chemical etching, in the case of glass.
• Such an improved blank can again be produced by heat-blowing a pasty sleeve, of flattened shape, produced by an extruder, then introduced into a mold suitable for this purpose.
• the temperature gradient in the spaces inter-plates of the active element of such an exchanger is multiplied by a factor at least equal to two. Consequently, with compact heat exchangers, making it possible to carry out a distillation, the Intrinsic Coefficient of Efficiency OE of the still with diffusion of vapor and heat-carrying gas which uses them, is, by construction, multiplied by at least four. To this, it should be added that, in the case of an active glass element, the thermal conductivity of this material is 1.5 W / mK, ie seven times more than that of polymers. This significantly increases the total thermal conductance to take into account and, in Figure 2, brings the maximum of the GE to a value of 270 instead of 95.
• FIG. 4 shows the diagram of a vapor diffusion still, using the liquid to be distilled as heat transfer fluid flowing from bottom to top inside hot hollow plates;
• FIG. 5 represents the diagram of a steam diffusion still, using large hollow plates for the thermal exchanges of distillation and an incondensable gas, saturated with vapor of the liquid to be distilled, as heat transfer fluid circulating from top to bottom of these hollow plates;
• FIG. 6 shows the diagram of a steam diffusion still, using flexible hollow plates for thermal distillation exchanges and an incondensable gas, saturated with vapor of the liquid to be distilled, as
• FIG. 7 shows the perspective arrangement of a set of three large hollow plates, thin and flexible, with corrugated walls, usable for distillation heat exchange in a still according to the invention
• FIG. 8 shows the device for feeding six plates of even or odd rank of a set of these 5 large flexible hollow heat exchange plates according to the invention
• FIG. 9 shows the means according to the invention for spreading the liquid to be distilled on the coating of hot hollow plates of a still with vapor diffusion and heat transfer liquid
• FIG. 10 shows the side and top views of a monoblock distillation heat exchanger, at low production cost, as well as cross sections of this exchanger and the blank, from
• FIGS. 11-12 are simplified perspective representations of an overall view and details of a still with diffusion of vapor and heat-carrying gas circulating from top to bottom inside rigid hollow plates, forming part of '' monoblock distillation heat exchangers;
• FIG. 13 shows a partial simplified perspective view of a still with diffusion of vapor and gas' .5 coolant flowing from bottom to top inside hollow plates, thin, flat and flexible distillation.
• two plates 10-12 symbolically represent a distillation block with vapor diffusion and heat transfer liquid, constituted by a set of large plates rigid alveoli (from 50 to 150 dm 2 ), of
• hollow plates 10-12 have a small internal thickness (2 to 3 mm for example) and are separated from each other by a narrow free space 14, having a thickness of approximately 5 mm, filled with an incondensable gas, in particular of air at atmospheric pressure.
• the hollow plate 10 is said to be hot since it is used for the evaporation of the liquid to be distilled and, for this purpose, it is provided with a coating
• the hollow plate 12 is said to be cold since it is assigned to the condensation of the vapor diffused in the incondensable gas. It preferably comprises an identical coating 15.
• thermosyphon a heat transfer liquid constituted by the liquid to be distilled.
• This boiler 18 will be of any type available, in particular with a solar collector or a burner.
• the circulation of the heat transfer liquid is done from top to bottom in the hot evaporation plate 10 and from bottom to high in the cold condensation plate 12.
• the temperature of the liquid entering the plate 10 is Ti and that of the same liquid, spread over the top of the coating 16, by means of an appropriate device 11c, quickly becomes slightly lower than Ti , due to its rapid evaporation.
• the heat transfer liquid has cooled, however, the liquid spilled on the coating 16 evaporates and its vapor diffuses into the noncondensable gas.
• the temperature of the heat transfer liquid at the outlet of this plate 10 is T3.
• This exchanger 22 is of the compact type, at low cost, which will be described in detail below.
• This exchanger 22 includes two active exchange elements 24-
• the ratio D / d of the flow rates of the circulating liquids D and incoming d is between 8 and 12, depending on the efficiency of the exchanger 22 and the usual temperature of the incoming flow.
• sea leaving the mixer 20 enters the cold plates 12 through a connection device 13b, identical to the device 13a.
• the condensation of vapor on the external face of the plate 12 causes a gradual increase in the temperature of the circulating liquid, so that, at the outlet of the plate 12, this liquid is at a temperature T2.
• the fresh water, condensed on the outer face of the plate 12 flows at a temperature close to T 4 , and the brine, at the bottom of the coating 16, at a temperature close to T 3 .
• the compact heat exchanger 22 being switched off, the cold sea water at 25 ° C. is directly mixed with the heat transfer liquid leaving T3 from the hot plates 10.
• FIG. 4 represents the diagram of a vapor diffusion still, according to the second embodiment of the invention, in which the direction of circulation of the heat-transfer liquid in the hot plates, is from bottom to top, conversely from that of FIG. 3. Consequently, the components of the two distillation blocks of FIGS. 3 and 4 are identical, and the diagram is substantially symmetrical to that of FIG. 3, their other components being, for their part, identical or equivalent . They all have the same reference numerals, with however an additional premium sign (') for those of FIG. 4. This, in order to differentiate them from each other, the ways in which they are linked together being different.
• the inlet of the hot hollow plate 10 ′ is connected, by its bottom fitting 11 ′ a and a conduit 11 ′, to the outlet of the heating chamber 19 ′ of a boiler 18 ′, equipped with a heating tube 17 '.
• the outlet of the hot plate 10 ′ is connected, by its high connector 11 ′ b, to one of the inputs of a mixer 20 ′, the other input of which is connected to a tank 36 ′ containing sea water to distill.
• the outlet of this mixer 20 ' is connected to the inlet of the cold hollow plate 12', by a conduit 13'b.
• the outlet of this plate 12 ' is connected, by its bottom fitting 13'a, to the inlet of the heating chamber 19' of the boiler 18 '.
• the brine and fresh water produced are discharged through 30 'and 32' gutters.
• the temperatures at the inputs and outputs of the hot plates 10 '(Ti, T3) and cold 12' (T4, T2) are substantially identical to those that can be had with the still according to Figure 3
• the overall efficiency of this still according to Figure 4 it will obviously be lower than that of the still according to Figure 3, since the temperatures of the fresh water and the brine evacuated (close to Ti and T2) are much higher than those (close to T3 and T4) that we obtain in the case of Figure 3.
• This type of still remains however a second interesting possibility of implementation of one of the liquid distillation processes coolant according to the invention, since this drawback can be easily corrected.
• Figure 5 is the block diagram of a first steam diffusion still using air, saturated with vapor of the liquid to be distilled, as heat transfer fluid. It has the particularity of circulating the air from top to bottom inside hollow distillation plates. This device constitutes the third embodiment of a still according to the invention.
• the internal 50 and external 52 faces of one of the two walls of a large rectangular hollow distillation plate 54 respectively border its internal volume 56 and the free space 58 which separates two neighboring plates.
• This plate 54 symbolically represents a distillation block, with diffusion of vapor and heat transfer gas, constituted by a large number N of hollow distillation plates, flexible or rigid, separated by narrow inter-plate spaces.
• the external face 52 of the wall of the plate 54 comprises a hydrophilic coating 60.
• n of auxiliary hollow plates for preheating the liquid to be distilled. They are similar to the previous (N) plates but without coating.
• auxiliary hollow plates are symbolically represented by a pipe 66, crossed by the liquid to be distilled, which occupies a space 67, delimited by the internal faces of the walls 62-64 of an envelope 63.
• Most of the air current hot heat carrier enters the upper end 57 of the hollow plate 54 and a small part, in that 68 of the space 67.
• a passage 70 By a passage 70, the bottom of the space 67 communicates directly with the outlet of the interior 56 of the hollow plate 54.
• the pipe 66 is provided at the bottom with an inlet 72 and at the top, with an outlet 74.
• a reservoir 76 containing the liquid to be distilled (brackish water, for example), at the temperature Tu, is installed above the still and, by gravity, it feeds this still, through a flow control valve 78 and a pipe 77.
• the liquid to be distilled is first introduced into an appropriate heat exchanger 80, operating against the current.
• This exchanger 80 comprises, in a casing 82, a monobloc active element 84.
• the inlet of the active element 84 is connected to the pipe 77 bringing the non-potable water to be distilled and its outlet connected, by another pipe 86, to the inlet of the casing 87 of a compact heat exchanger 88, operating against the current.
• the air streams leaving the N hollow distillation plates 54 and n the auxiliary hollow preheating plates 66 pass through the inlet of the casing 82 of the heat exchanger 80 and for this purpose this inlet is connected to their common outlet 90.
• the outlet 81 of the casing 82 is connected upstream of the fan propeller 92, installed in the lower part 94 of the inter-plate space 58.
• a long plate 98 covered with a sponge mat 100, (a thick layer of hydrophilic fabric, for example), provided with a bottom pierced with numerous holes connected to distribution conduits 102, installed just above the coverings 60 of these N plates 54.
• the brine collection conduit 104 which flows at the bottom of the coatings 60, opens onto an evacuation gutter 106.
• the conduit 108 for collecting the thin film 110 of distilled water which flows on the internal faces 50 of the walls of the N hollow plates 54, is joined by the conduit 112 for collecting the distilled water, condensed on the external walls of the pipe 66 symbolizing the n hollow auxiliary preheating plates, before being connected to the inlet of the one-piece active element 114 of the heat exchanger 88.
• the outlet 115 of this element 114 as well as the outlet 83 of the casing 82 lead to a gutter 116 of distilled water.
• the casing 87 of the heat exchanger 88 is crossed by the liquid to be distilled, its outlet being connected to the inlet 72 of the pipe 66, representing the n preheating plates for this liquid.
• the outlet 74 of the pipe 66 is connected to the inlet of the heating chamber 118 of a boiler 120, provided with a hot source 122.
• the heating chamber 118 has an outlet duct 124 which feeds a head of sprinkler 126, installed lengthwise just above the sponge mat 100 covering the plate 98.
• the maximum temperature of brackish water to be distilled contained in the heating chamber 118 is lower than its boiling point.
• the hot spring 122 for example adapted to supply brackish water at a maximum value of 95 ° C., for a given flow rate of entry of this water, fixed once and for all by an adjustment
• the vapor carried by this air flow condenses on their internal faces, while this air flow cools, that the brackish water which flows along the coating 60 evaporates in part and that that which rises in the pipe 66 heats up.
• the temperature T3 of the heat transfer air is 68 ° C. and, at the bottom of the n hollow auxiliary plates for preheating the liquid to be distilled represented by the pipe 66, the temperature of this air is of about 42 ° C.
• the temperature of the mixture is approximately 62 ° C.
• the liquid to be distilled enters the active element 84 of the heat exchanger 80, at a temperature Tu of 25 ° C. for example. It circulates there against the flow of heat transfer air.
• Tu temperature
• the liquid gains 5 ° C while the flow of heat-transfer air, which has passed through the envelope 82 loses 32 ° C for meet at a temperature T 4 of
• the brine flowing from the coating 60 of the N hollow distillation plates 54 is at a temperature close to T4 (30 ° C.), that is to say at a temperature close to that (25 ° C.) of the brackish water to distilled. Consequently, its evacuation is done directly by the conduit 104 and the gutter 106.
• the distilled water at the inlet of the active element 114 of the countercurrent heat exchanger 88 is at a temperature of 62 0 C approximately, that same heat transfer air at the inlet of the casing 82 of the heat exchanger 80. It is therefore entirely justified to recover the thermal energy from this distilled water and to neglect that washed away by brine.
• the ratio between the total area of the N distillation plates 54 and that of the n auxiliary plates symbolized by the pipe 66 is from six to ten approximately and the heat exchangers 80 and 88 will, by construction, be adapted to the desired results.
• the optimal value of the composite variable t.dH / V will be relatively high, when the boiler 120 is supplied with free thermal energy (solar boiler or cooling water of a heat engine, for example ).
• FIG. 6 is the schematic diagram of a second steam diffusion still using air, saturated with vapor of the liquid to be distilled, as the heat transfer fluid.
• This device has the particularity of circulating the flow of heat transfer air from bottom to top inside the hollow plates, unlike that of FIG. 5. Consequently, the components of the two distillation blocks are identical and this diagram is substantially symmetrical to that of FIG. 5, several of their other components being identical or equivalent. All of them bear the same reference numbers, with however an additional premium sign (') for those of FIG. 6. This, in order to differentiate them from each other, the ways in which they are linked together being different.
• This device constitutes the fourth embodiment of a still according to the invention. According to FIG.
• a wall 54' of a hollow, thin and flexible plate having an internal space 56 'and an inter-plate space 58' between two adjoining plates, is drawn. To simplify the drawing, these two spaces 56 ′ and 58 ′′ are limited by the lines defining the chamber 48 ′.
• the assembly symbolically represents a distillation block, with diffusion of vapor and heat transfer gas circulating by natural convection.
• Each hollow plate has two walls 54 ', two bare internal faces 50' and two external faces 52 'provided with a hydrophilic coating 60', as well as an inlet 57 ', located in its lower part, and an outlet 55', located in its upper part.
• the inlets 57 'of the hollow plates of said assembly are connected, by a low chimney 59', of appropriate height, to a saturated hot air generator, described below.
• the outlets 55 'of the hollow plates open out into a wide space 79 ′, of appropriate height, occupied by a monobloc active element 84 ′ for heat exchange.
• This space 79 ′ constitutes the upper chimney of the treatment chamber 48 ′ of the still. It extends beyond the 'active element 84' by another he wide space 81 'which ends above the entrances 94' of the inter-plate spaces 58 'of said assembly.
• the outlet 96 'of the inter-plate space 58' opens onto a large collecting space 83 '.
• a tank 76 ′ containing for example sea water to be distilled, is installed at a suitable distance above the treatment chamber 48 ′ to feed by gravity, through a pipe 77 ′ and a tap 78 ′, the one-piece active element 84 'for heat exchange.
• the outlet of this element 84 ' is connected by a hose 86' to pouring spouts 102 ', arranged just above the upper edges of the walls of the plates hollow 54 'of said assembly and their hydrophilic coatings 60'.
• the brine which descends along the coverings 60 ' ends in a single collection gutter 103', connected by a pipe 104 'to another gutter 105', intended to supply brine to a particular solar boiler 120 '.
• This solar boiler 120 ′ is adapted to evaporate part of this brine and to diffuse its vapor in a stream of air, 5 in order to constitute said saturated hot air generator.
• the bottom of the heating chamber 118 ′ of this boiler 120 ′ is constituted by a black sheet 122 ′ of composite material (for example, polymer film or oxidized metal sheet with insulated rear face, on one side , and non-woven of cellulose or polymer, on the other), impermeable and unalterable on the black side and more or less hydrophilic on the other.
• This tablecloth 122 ′ is installed on a rigid grid and its black face, exposed obliquely to solar radiation (S) in agreement
• This reservoir 63 ' is intended to collect the brine which flows from the hydrophilic coating of the sheet 122'.
• the reservoir 63 ' comprises a 0 drain pipe 128', provided with a tap 130 'disposed upstream of a gutter 106' for removing the brine, both installed outside the chamber 48 '.
• the distilled water which has condensed into a film 110 'on the internal faces 50' of the walls 54 'of the various hollow plates, is collected in a single gutter 109', itself connected by a pipe 115 'to a drain gutter 116 ', installed outside the chamber 48'.
• distilled water condensed on the external faces of the active exchange element
• the black face of the web 122 ' installed at the bottom of the greenhouse 118', absorbs solar radiation (S), heats the brine which permeates the thin hydrophilic carpet of its other side, evaporates part of its water and diffuses the vapor produced in
• this air is thus gradually reheated and kept saturated and it becomes, by natural convection, a current of saturated hot air which crosses the low chimney 59 'then enters the interiors 56' of the hollow plates, through their inlets 57 ', and then it circulates from bottom to top in these vertical hollow plates then in the high chimney 79' and along the external faces of the active monobloc heat exchange element 84 '.
• This heat exchange element 84 ′ is traversed by the seawater flow at
• the height of the distillation plates and those of the low and high chimneys are chosen at the same time, taking into account the maximum value of the temperature Ti (which must remain within the concerned range of its optimal or simply effective values) of the air flow circulating by natural convection, which the solar boiler can produce 120 .
• the temperature Ti of the air flow is limited due to the solar boiler without reflector used, but this temperature remains in its optimal range, that is to say approximately between 70 and 80 ° C., at least when the sun is high.
• the air flow which leaves the hollow plates at a temperature T3 close to 68 0 C is cooled and its temperature drops to an optimal value ⁇ 4 very low, namely about 30 0 C, when the effectiveness of the one-piece active element 84 'is appropriate.
• the outlet pipe 86 'of the active element 84' of the heat exchanger 80 ' supplies the pouring spouts 102' with sea water at a temperature of approximately 50 ° C.
• This lukewarm sea water thus poured onto the coverings 60 'descends slowly along the external faces 52' of the walls 54 'of the hollow plates. Consequently, the water vapor carried by the saturated hot air current, which rises inside 56 ′ of the hollow plates, condenses on the internal faces 50 ′ of the walls of these plates and forms a thin film of 110 "distilled water.
• this sea water heats up, under the action of the latent heat of condensation recovered through the walls 54 ′ of the hollow plates.
• this water partly evaporates and the vapor produced diffuses into the stream of cooled air, which descends into the inter-plate spaces 58 ′, and thus gradually heats this current.
• the temperature of this air stream reaches a T2 value of approximately 78 ° C.
• the brine collected at the bottom of the hydrophilic coatings 60 ′ of the walls 54 ′ of the hollow plates, its temperature is also approximately 78 ° C.
• This brine collected by the gutter 103 ' is brought through the conduit 104', da ns the gutter 105 'for supplying, by capillarity and gravity, the hydrophilic rear coating of the sheet 122' with a black front face, installed at the bottom of the heating chamber 118 'of the particular solar boiler 120'.
• the maximum temperature of this heating mat 122 ′ and of the brine that its coating contains is at most 85 ° C. (such a solar boiler without reflector hardly makes it possible to reach a higher temperature).
• a small part of the water in this brine evaporates and the rest flows slowly into the tank 63 ', which gradually fills with a little more concentrated brine, the temperature of which is around 82 0 C, intended to be evacuated.
• the vapor thus produced on the surface of the hydrophilic coating of the heating sheet 122 ′ is carried away by the air current which has emerged from the inter-plate spaces 58 ′ then swept the surface of the hot brine contained in the tank 63 ′ and, with about a degree thus gained, penetrated with a temperature of a little more than 78 0 C, at the foot of the constantly humid warm coating of the web 122 ', along which it heats up and saturates again.
• the interest of this still with diffusion of vapor and current of coolant air flowing from bottom to top in the hollow plates, is multiple if we compare it to the still of Figure 5, in which the stream of coolant air flows up and down inside these plates.
• the first advantage lies in the fact that no propellant (fan or jet of steam) is necessary to ensure the circulation of this current of air, since this circulation is here generated by natural convection.
• the second advantage comes from the fact that the temperature of the hot source can be between approximately 75 and 85 ° C. and nevertheless remain effective since it is capable of ensuring, at the entry of the hollow plates, a temperature Ti which is still optimal. or simply effective. This has the direct consequence of adding a third advantage, namely making a solar boiler without a reflector, perfectly suited to such a still.
• a fourth advantage lies in the total absence of moving parts operating continuously. This constitutes a particularly advantageous advantage (elimination of any maintenance generally required by such parts) in all cases where this type of still is used in a non-industrial environment.
• a fifth advantage appears in the fact that a very large coefficient of performance COP of the still can in principle be obtained, since the increase in temperature of the brine, brought by the boiler, can be very small ( ⁇ 2 ° C. ).
• the temperatures of the brine and of the distilled water to be discharged are high (around 82 ° C.), but we will describe later, in the commentary to figure 13, how it is possible to recover this thermal energy to diffuse an additional vapor in the current of coolant air and thus considerably increase the COP of the device.
• a sixth advantage comes from the considerable increase of the GE, stated above, which results from the very low wall thickness and hydrophilic coating, presented by the new type of thin hollow plate, with flat walls, flexible and very thin, described below in FIG. 13.
• the comments which accompany this FIG. 13 relate to an embodiment real of a still with diffusion of vapor and heat transfer gas, circulating in closed circuit by natural convection. They will confirm, by the low manufacturing cost of this new hollow distillation plate, the particularly great interest of this last embodiment of the invention.
• FIG. 7 schematically represents three large flexible hollow plates, provided with their frame and their connection washers.
• FIG. 8 represents a view in longitudinal section of one of the four devices for feeding a large number (6, in the drawing) of large hollow rectangular plates of even or odd rank, ensuring heat exchanges in a still, according to the invention, which operates with a liquid heat transfer fluid.
• FIG. 9 it represents the device ensuring the distribution of the hot liquid to be distilled, on the hydrophilic coatings of the only plates assigned to the evaporation of this liquid, when the heat transfer fluid is a liquid.
• each flexible rectangular plate 140i, 2,3 which measures for example, 120 cm high and 100 cm wide, is made from a thin sheet (in particular, of polypropylene), provided with a coating welded hydrophilic (in particular, a nonwoven of cellulose, shown in dotted lines), folded in half, the fold constituting the upper edge of each plate.
• a thin sheet in particular, of polypropylene
• a coating welded hydrophilic in particular, a nonwoven of cellulose, shown in dotted lines
• each plate 140i, 2,3, located above the oblique line 144i, 2,3, constitutes a sheath 150i, 2,3, the two ends of which are cut, to make room for a large and a small cuts 152i, 2,3 and 153i, 2,3.
• two weld lines 154i, 2,3 and 156i, 2,3 are made, parallel to the previous ones, which constitute the outer edges of each plate 140i, 2 3.
• These same lines 154-156 in cooperation with the outer line, extended by its two ends, which borders the first and the last duct of each plate, delimit two vertical sleeves 158i, 2,3 and 160i, 2,3, of about 4 cm wide, over the entire height of the elements.
• Such flexible plates have corrugated walls.
• the two sides of the wall 162i, 2,3, located below the low oblique line 146i, 2,3 of each plate, are folded upwards to constitute, with the external wall of its common bottom channel 163i, 2,3 , two slippers for collecting liquids which have seeped into the hydrophilic coatings of the two walls of the plates 140i, 2,3.
• a gutter (not shown) is disposed under the lower ends of the two collection slippers of each plate, so that, due to the opposite orientations of the slippers of two adjoining plates, one of the gutters will collect the liquid which flows from the cold plates of odd rank and the other, that of hot plates of even rank.
• Each plate 140i, 2,3 has a semi-rigid frame which includes two horizontal rods and two vertical blades, both made of steel, for example, or of a reinforced polymer with high mechanical resistance.
• the rods have a U-shaped section, one high 164i, 2.3 in inverted U, for the suspension of the plate and the other low 1661.2.3 in right U, to give it a longitudinal tension and complete the 'framing.
• the external thickness of these rods is 3 mm, their height 10 mm and their wall thickness 1 mm.
• the ends of these rods have, recessed on their sides, two steps (not shown).
• the openings of the inverted U rods 164i, 2,3 are engaged on the ends of vertical blades 1681,2,3 and 170i, 2,3, with rounded edges, having 3.5 cm wide and 1 mm thick.
• the spacing of these blades is imposed by that of the stops constituted by the redents of the rods.
• the rods 164i, 2,3 as well as the blades 1681,2,3 and 170i ⁇ , 3 are respectively engaged in the horizontal sleeves 150i, 2,3 and vertical 1581,2,3 and 160i, 2,3.
• the spacing of these blades which is kept fixed by the U-shaped rods 164-166, determines the initial transverse tension of the flexible plates 140i, 2,3.
• Each plate 140i, 2,3 has, in the wide, diagonally opposite corners, its top common channels 1481,2,3 and bottom 163i, 2,3 of the washers 172i, 2,3 and 174i, 2,3 of these common channels. These washers and these common channels cooperate to ensure the distribution or recovery of the heat transfer fluid entering or leaving these conduits.
• These washers in FIG. 7 represent the location of the feeders for the even or odd assemblies (illustrated in FIG. 8), which pass through the large cutouts 152i, 2,3 of the sleeves 150i, 2,3.
• Such rigid cellular plates have planar walls.
• the device for supplying six hollow plates of even or odd rank comprises a stack of six washers 172i-6, associated with a T-shaped connection 180, comprising a first pipe
• Each of the washers 172i-6 is a ring which measures, for example, approximately 17 mm thick and 4 cm inside diameter, in the case of hollow plates of one m 2 provided for a still against the current of water.
• Each ring is provided, in its central part, with a circular rim 1881-6, the lateral faces of which are welded to the internal faces of the walls 190i-6 and 1911-6 with a
• each washer 172i-e has an external shoulder 1711-6 and its upstream edge, an internal shoulder 173i-6.
• the circular rim 1881-6 of each washer 172i-e are drilled several horizontal holes, such as 192, 3.5 to 4 mm in diameter (8 holes, according to the drawing) which, on one side, lead to the inside the washer and on the other, inside and lengthwise of the
• the tie rod 186 comprises (1) a support base 194, provided with an internal shoulder 195, adapted to cooperate with the external shoulder 171i of the downstream washer 172i, (2) a frustoconical rod 196, the length is determined by the number of washers 172 to be stacked (one hundred, if applicable) and (3) one
• the pipe 182 of the fitting 180 comprises, welded and / or glued at its two ends, supports respectively constituted by a cup 200, pierced at its center and a ring 202, provided with an external shoulder 203, adapted to cooperate with the internal shoulder 173 ⁇ of the washer upstream 172 ⁇ .
• the support cup 200 is adapted to slide on the end 198 of the tie rod 186.
• This end 198 has a housing for an O-ring seal 204.
• FIG. 9 represents, in cross section, the upper part of a set of nine flexible plates, comprising five cold plates of odd rank 140i, 3,5,7,9 and four hot plates of even rank
• This waterproof cap is made by means of a waterproof sheet with hydrophilic coating, identical to the material constituting the flexible plates, its hydrophilic coating 2173,5,7 being in contact with that 2122,4,6,8 of the plates of even rank 1402 , 4,6,8.
• the end intermediate plates 214i and 214 ⁇ , of a set of plates 140i-9, are separated from the plate 1402 for one and from the plate 140 ⁇ for the other, by a waterproof sheet with hydrophilic coating 218 and
• hydrophilic mat 2226 is, for example, made up of several layers of cotton fabric. Above this mat, are installed from place to place, pouring spouts, such as 228, adapted to
• the conduits of the flexible plates can only take a limited internal thickness, of approximately 2 to 3 mm, in response to the pressure exerted by the heat-transfer liquid which circulates there.
• the top common channels 148 and bottom 163 are themselves prevented from swelling under this same pressure. Under these conditions, the thickness of the free space between the plates 140 is maintained at a correct value, namely approximately 5 mm.
• the pitch of assembly of these plates 140 it equals half the distance separating the internal and external shoulders of the connection washers 172i-9, or 8.5 mm.
• these washers it will be noted that their stacking, under the action of the tie rod 186, is made in a sealed manner, which makes it a leak-free pipe, of modular length.
• the holes 192 allow, without significant pressure drop, to bring in or out the heat transfer fluid in the upper or lower common channels of each hollow plate. Thanks to the arrangements according to FIG. 9, in a still with a liquid coolant, the coatings of the hot plates, assigned to the evaporation of the hot liquid to be distilled, are the only ones likely to be wetted by this liquid.
• FIG. 10 shows in A-B, side and top views of a low-cost compact heat exchanger and in C-D, cross sections of this exchanger and the outline of its one-piece active element.
• the compact heat exchanger 250 comprises a casing 252 which completely surrounds an active exchange element 254.
• This active element 254 consists of the stacking of a relatively high number Qusqu'à 30, by example) of pairs of 256 ab hollow plates, both elongated, symmetrical and communicating.
• the cross section of the active element 254 has the shape of a fish spine, provided with hollow edges 256 ab, oblique and parallel to each other, which share a common central channel 258.
• the internal thickness of these edges 256, their separation gap 260 and their common central channel 258 is small and substantially identical (2 mm, for example).
• the thickness of the walls of the active element 254 is thin (0.5 mm, for example).
• Each hollow plate 256 a-b of the active element 254 has a rectilinear central part whose length can vary from 30 to 100 cm approximately and the width from 5 to 15 cm approximately.
• a hollow plate 256a is connected to its symmetrical plate 256b by two hollow end fittings 262-264, in the form of half truncated cones.
• the stacking axes of these half-truncated cones coincide with the axes of the two collectors which supply the different pairs of stacked hollow plates 256 a-b and they terminate in the two connecting pipes 266-268 of the active element 254.
• the envelope 252 is shown transparent for the purposes of the drawing in FIG. 10A. It is formed of two half-shells 251-253, with convex and concave bottoms respectively, assembled in a sealed manner (welding, bonding or seal) by their assembly flanges 255 ab and 257 ab.
• the gap between the envelope 252 and the edges of the plates 256 of the active element 254 is small (of 1 mm, for example) but it is zero along the crest 270 of its convex wall and along the hollow 272 of its concave wall.
• the casing 252 has two coaxial connection pipes 274-276 and two lateral openings through which the connection pipes 266-268 of the active element 254 pass, the edges of these openings being welded, glued or assembled with a gasket. sealing at the root of these two pipes 266-268.
• Figure 10D shows the cross section of the heat blown blank 276, from which the active heat exchange element 254 was made.
• This blank 276 comprises a stack of relatively long biconvex bellows 278, provided with relatively short end connections (see FIG. 10A) in the form of symmetrical half-truncated cones.
• the stack of bellows 278 is comparable to an accordion whose bellows would have level ridges 280 and narrow bottoms 282, with bellows depths sufficiently large in front of the large diameter of the end half-cones, to allow the latter to constitute returnable surfaces, implying a transition buckling during their reversal.
• the transformation of the blank 276 into an active element 254 is carried out under the action of an axial force of controlled compression. This force has the effect of causing each of the two symmetrical flanks of each half convex bellows to pass from one stable state to another, by becoming parallel to one of the two symmetrical flanks of each concave half bellows which is associated with it.
• the blank 276 makes it possible to produce an active conventional heat exchange element.
• the walls of a polymer blank 276 are provided with a thin hydrophilic coating 284, preferably preformed, having for example 0.1 mm of thickness.
• the blank 276 will, again, be produced by heat blowing a pasty polymer sleeve, of flattened shape, produced by an extruder, then introduced into a mold comprising multiple parallel grooves, previously filled with the coating. 284.
• the process for manufacturing the blank is substantially identical to that used for polymers.
• FIG. 11A is an overall view of such a module.
• Figure 11B shows the details of this module and Figure 11 C, a cross section of one of the heat exchangers used.
• Figures 12 A-B they show the details of the pipes and connections of the various fluids circulating in the still.
• the still 290 is a module comprising first of all (1) eight compact, vertically arranged distillation heat exchangers, 292i-s, intended to ensure evaporation of the liquid to distill then a condensation of its vapor, and (2) a simple compact heat exchanger 294.
• FIG. 12C which is the section along the plane CC of FIG. 11 B, the active element 293i- ⁇ of each compact exchanger 272i- 8 , has eight pairs of small hollow plates thin, united, symmetrical.
• FIG. 12C which is the section along the plane CC of FIG. 11 B
• the active element 293i- ⁇ of each compact exchanger 272i- 8 has eight pairs of small hollow plates thin, united, symmetrical.
• these pairs of plates are provided with a hydrophilic or wettable coating 284i- ⁇ and with a cap in hydrophilic fabric 286i- ⁇ , ensuring a uniform distribution of the liquid to be distilled over all the coatings 284i- ⁇ .
• each plate of the eight symmetrical pairs of an active element 293- ⁇ - ⁇ has
• each active element 293i- ⁇ is approximately 1 m 2 and its total volume of 2.5 dm 3 .
• the active volume V of a module of eight elements is 20 dm 3 and its total heat exchange surface, 8 m 2 .
• the eight active elements 293- ⁇ - ⁇ with vapor diffusion are grouped in a
• each active element 293i- ⁇ is associated with two coaxial entry doors 298i- ⁇ and exit 300i- ⁇ , arranged in the part of the envelope which surrounds it.
• each active element 293- ⁇ - ⁇ with vapor diffusion comprises, in its upper part, a side entry door 302i- ⁇ and, in its lower part, a side exit door
• the simple heat exchanger 294 comprises an active element 295, provided with side entry and exit doors 305-307 and a casing 308, provided with two coaxial entry and exit doors 310-312.
• a sea water tank 314 is installed connected, by a pipe 316a-b and a tap 317, to a conduit 318 which passes through a tube 320, into which the eight exit doors open 304i- ⁇
• the duct 318 is connected to the inlet of the casing 322 of a heat exchanger against the current 324 and the outlet of this enclosure is connected, by a pipe 319, to an anteroom 326, preceding the entry door 310 of the enclosure 308 of the simple compact exchanger 294.
• This exchanger 324 makes the object, in figure 11 B, of a symbolic representation but, in figure 12, its representation is more
• This heat exchanger 324 is of the compact type and it includes an active element 328, the cross section of which is shown in FIG. 11 C. The function of this element 328 will be specified below.
• the sea water which leaves the exchanger 324 passes through the heat exchanger 294 and then leaves it, through its outlet door 312, to enter a boiler 332.
• the boiler 332 comprises an inlet part 334, extended by a tube of
• radiator 338 has an inlet 340 and an outlet 342, both external to the boiler 332, and it is adapted to be traversed without damage by an appropriate heating fluid ( gas or hot liquid from 105 to 120 0 C).
• the radiator 338 may be made of a metal, adapted to resist possible corrosion of the heating gas used, or of a polymer having good mechanical strength at the temperature of the hot liquid.
• the heating tube 336
• 35 comprises at its downstream end (1) a partition 344, crossed by the tubular radiator 338, (2) in the upper part of this partition 344, one or more calibrated orifices 346, adapted to generate one or more jets of steam 347, when sea water boils in this heating tube 336 and (3) in the lower part of this same tube 336, one or more holes associated with one or more short pipes 348, of calibrated section, adapted to ensure appropriate withdrawal of this water.
• the boiler 332 is enclosed in an elongated cylindrical duct 350, of circular section, arranged horizontally and, in the lower part of this duct, open the outlet doors 312 and 300i- ⁇ of the casings 308 and 296 of the heat exchangers 294 and 292i- ⁇ . Entrance room 334 of this boiler occupies the upstream end of the duct 350 and it includes, shortly after the outlet door 312 of the casing 308 of the exchanger 294, a thick partition 352, pierced in its center with a truncated cone opening 354, occupied by a shutter 356 with identical profile, adapted to gradually close this opening when it is pulled upwards.
• the shutter 356 is connected to a float 358 by two connecting rods 359a-b, between which passes the downstream end of a tubular radiator 338.
• the float 358 causes the needle shutter 356 to completely close the inlet opening 354 of the boiler, which thus operates at a constant seawater level, located above the tubular radiator 338.
• a chamber 360 of overheating and supersaturation of the heat-carrying gas occupied by a narrow and slightly hollow plate, covered with several layers of hydrophilic fabric 361.
• this plate is pierced with eight calibrated holes, located just above the eight exit doors 300i- ⁇ of the casing 296 of the active elements 293i- ⁇ with vapor diffusion.
• the horizontal cylindrical conduit 350 surrounding the heating tube 336 of the boiler 332, is connected by a bent tube 364 to another horizontal cylindrical conduit 366.
• the active doors 302i- ⁇ open out. vapor diffusion 293i- ⁇ and the entry door 305 of the active element 295 of the simple heat exchanger 294, while the exit doors 304- ⁇ - ⁇ and 307 of these same active elements open into the conduit 320
• This duct 320 is connected by a bent pipe 368 to another horizontal cylindrical duct 370, into which the entry doors 298i- ⁇ of the casing 296 of the active elements 293i-déb open.
• the duct 370 comprises, at its downstream end, a partition 371 which separates it from the anti-chamber 330 of the casing 308 of the simple heat exchanger 294, the outer wall of this anteroom extending that of the duct 370.
• the horizontal conduit 320 At the bottom 372 of the horizontal conduit 320, accumulates the distilled water which flows from the exit doors 304i-8 and 307 of the active elements 293- ⁇ - ⁇ and 295 and that which has condensed on the external wall of the pipe 318 traversed by cold sea water.
• the brine On the bottom 374 of the horizontal duct 370, the brine accumulates which flows from the heat transfer gas inlet doors 298i- ⁇ of the casing 296.
• This bottom 372 is connected to the inlet of the active element 328 from the exchanger 324 (see fig. 12B), via a pipe 376.
• the outlet of this active element 328 leads to a pipe 378 and a drain gutter 379 for distilled water, however the brine accumulated at the bottom 374 of the conduit 370 is evacuated by a pipe 380 and a gutter 381.
• the active element 84 crossed by cold water to be distilled, from the heat exchanger 80, replaced by the conduit 318 likewise passed through, the casing 82 being replaced by the horizontal tube 320 and the exchanger 88 is replaced by the exchanger 324.
• the heat exchanger 80 or that constituted by the tube 318 and its casing 320 is an essential component of the still with diffusion of vapor and heat transfer gas, according to the present invention. Its function is to lower the temperature of the heat transfer gas leaving the hollow plates by several tens of degrees, before bringing it into the inter-plate spaces. This, in order to have at the entry of the inter-plate spaces, a local difference dH of enthalpy flow substantially equal to that generated by the hot source between the exit of these spaces and the entries of the hollow plates, taking into account of the very great difference which exists between the apparent heat capacities Cp of saturated air at the temperatures concerned.
• the heat exchangers 88 and 324 are intended to recover the thermal energy of the distilled water to be discharged, in order to best improve the COP of the still.
• the liquid to be distilled entering the inter-plate spaces of the compact heat exchangers 294, leaves one or more other heat exchangers 324 of the same kind, arranged between the outlet (s) of the heat exchangers 292-294 and the collection means 376 for distilled liquids which condense on the internal faces of the active elements of the heat exchangers 292 and 294 and on the walls of the duct 318 of the heat exchanger 318-320 or its equivalents 250.
• auxiliary hollow plates represented by the pipe 66 and its casing 63, or by the exchanger 294, producing a complementary heat exchanger between the hot saturated heat-transfer gas and the liquid to be distilled, before that -this enters the heating chamber of the boiler 120 or 332.
• such a quantity of movement capable of propelling a current of hot air from top to bottom of thin hollow plates then this same current cooled from bottom to top of narrow inter-plate spaces, by overcoming the different pressure losses undergone, during such a closed loop path, can be obtained by bringing the sea water to 102 0 C in the heating tube 336, which will generate one or more relatively powerful jets of steam, at 80 millibars of overpressure, ejected at 150 m / s.
• Such steam jets make it possible to overcome natural convection and also to eliminate the fan 92, provided for this purpose in the still of FIG. 5. This has the consequence of further reducing the amount of investment to be made and to significantly simplify the operation of the equipment.
• the heating tube 336 and the tubular radiator 338 constitute a heat exchanger for confined fluids circulating against the current.
• the characteristics of this exchanger (materials, diameters and lengths of the heating tube and the tubular radiator) will be determined according to the results to be obtained, taking into account the respective characteristics (types, flow rates, temperatures, heat capacities) of the heating fluid available and liquid to be distilled.
• Such steam production will be obtained, for example, by means of a suitable stainless steel tubular radiator capable of withstanding the various components of the exhaust gases at 300 ° C. of a diesel engine.
• the material used may be the same for both, (a polymer mechanically stable at these temperatures, for example). It would be the same if the heating liquid of the tubular radiator was thermal oil (like ESSO 500, for example) heated during the day by an appropriate solar boiler, equipped with a cylindrico-parabolic reflector, and stored day and overnight at high temperature (120 or 130 ° C., for example) and at atmospheric pressure, in a heat-insulated tank.
• thermal oil like ESSO 500, for example
• the embodiment of the boiler 120 has not been specified. In practice, it is possible to use either of the boilers described in FIGS. 11 and 12. It will be noted that the temperature of the water which it supplies is lower than its boiling point. In the absence of overpressure steam, the steam jet 347, used in FIG. 12 to circulate the heat transfer gas, cannot therefore be created by the boiler 120. Consequently, a mechanical propellant, a fan 92, must be used to circulate this gas. The case of a boiler incapable of producing overpressure steam is, for example, that of a solar boiler without a reflector.
• FIG. 13 represents the perspective view of a still with vapor diffusion and with heat-transfer gas circulating by natural convection, the distillation block of which is a set of thin hollow plates, flat and flexible, of a model particularly well adapted to this type of still.
• this figure 13 specifies the details of making a still according to FIG. 6, in which the solar boiler is replaced by a heating tube.
• FIG. 13 six thin hollow plates 400i- ⁇ appear. which symbolically represent a distillation block constituted by a large number of these same plates (several hundreds or even several thousands, if applicable) which can be installed on a frame (not shown) mounted in a heat-insulated treatment chamber 401
• This chamber 401 like chamber 48 ′ in FIG. 6, comprises three stages having approximately the same height: a lower stage for the low chimney, a central stage for the distillation block and an upper stage for the high chimney.
• several walls of this chamber 401 are represented by their
• each hollow plate 400 measures 40 cm wide, 50 cm high and 2 mm in internal thickness.
• such flat hollow plates, flexible and thin may have a maximum surface area of approximately 1 m 2 per side , a maximum width of approximately 80 cm and at most 5 mm internal thickness.
• Each plate 400 is formed from a thin sheet 402i- ⁇ in
• each ply 402i- ⁇ appears folded in half, carried by a hanging rod 404- ⁇ -e, coated on the outside.
• the 404i-e rods are in
• each ply 402i- ⁇ is welded to its suspension rod 404i-e and its lower part, similarly welded to a tension bar 406i-6.
• the rods 404i-6 and the bars 406- ⁇ -e are made of polymer identical to that of the tablecloth and they are all 2 mm thick and 50 cm long.
• Tension bars 406 have supports at their ends
• each tension bar 406i which has an oblique lower edge 410, connected at an angle to the end of this bar.
• a point 412 for drawing off the distilled water produced constituted by a transverse notch, 1 mm deep and 3 mm wide, the case if necessary, replaced or occupied by a wick
• each tension bar 406 is very open V-shaped, wedged on the notch 412.
• the sides of the plies 402i- ⁇ extend their tension bars 406i-e. These sections are raised and the folds formed at an angle, then crushed and held in place by any suitable means, in particular sewing stitches. In this way, are formed for each hollow plate 400, two flat conduits 414, inclined, parallel and contiguous, for collecting the brine produced by each hollow plate of the still. Under the
• the brine collected by the flat conduits 414 pours into a gutter 418 provided with pouring spouts 420a-b, disposed above a heating tube 422, covered with a thin hydrophilic carpet 424, with exposed sides.
• the length of this heating tube 422 corresponds to that of the set of plates
• the heating tube 422 is supplied with heating fluid by a pipe 423, this fluid being capable of bringing the temperature of the brine which permeates the carpet 424, to a maximum temperature of approximately 95 ° C.
• the tube 422 is installed in the low fireplace 426 of the still. This chimney 426 is formed between a thick thermal insulation panel 428 which divides the lower floor of the treatment chamber 401 into two communicating parts.
• This panel 428 forms, with similar panels, such 430 (only shown), which constitute the thermal insulation of the transverse walls of the lower stage of the treatment chamber 401, on the one hand, the unoccupied part 432, with a flat wall 433, of this lower stage and, on the other hand, the low chimney 426, with wall curve 427.
• a tank 434 is disposed in which ends the brine which flows hot from the mat 424 covering this heating tube 422.
• the hollow plates 400 are provided with a high chimney 436, constituted in the same way as the low chimney 426. This high chimney 436 opens onto a passage 435, formed between a block of thermal insulation 437 and the upper wall 439 of the treatment chamber 401.
• such a heat exchange assembly 438 has an air / water exchange capacity of approximately 170 Watts / ° C. and, for this purpose, it comprises thirty four bellows of 15 cm in diameter. long and 5 cm wide, with internal thicknesses of hollow plates and inter-plate spaces of 2 mm. Beyond the space occupied by these elements 438, appears the unoccupied part 443 of the upper stage of the treatment chamber 401.
• an elongated device 444 (open box shown or tube under slight pressure) for the distribution of lukewarm sea water brought in by the hose 442.
• the bottom of the distributor 444 has two rows of holes, drilled at the plate assembly pitch and traversed by wicks (not shown) spread out and fixed by a few clips, on the top of the hydrophilic coating of these plates.
• the suspension rods 404i-e of the hollow plates 400i-e are placed on two parallel horizontal beams, forming part of the chassis installed in the heat-insulated treatment chamber 401, and the tension bars 406 of these plates, under two horizontal adjustment beams tension, similar and parallel to the previous ones, connected to the chassis by springs.
• the height of the hollow plates 400 determines the distance between these beams and this is fixed once and for all.
• These beams, this chassis and these springs are commonplace components which are not shown, so as not to overload the figure.
• the individual tension force of each ply is approximately 200 to 400 grams, depending on the wall thickness and of the height of the tablecloths.
• a short spacer 448 is fixed to it at right angles.
• This spacer 448 which measures 22 cm long, 2 cm wide and 2 mm thick, is free between the two sides of the folded ply 402, its outer edge coinciding with the outer edges of these two sides.
• 5 cm from the opposite end of each of the tension bars 406, is also fixed at right angles, under the same conditions, another short spacer 450, visible through the tear 451, identical to 448.
• two diagonally opposite openings 452-I-6 and 454i-6 are arranged, 20 cm high and 2 mm wide, which constitute the inlets and outlets of the 400i-6 hollow plates.
• These inlets and outlets remain constantly open and the internal thicknesses of these plates are almost constant, due to the tensions uniformly generated in the free sides of the sheets, by the springs integral with the beams bearing on their tension bars and because additional bonding of the edges of the openings on the long spacers 456, described below.
• the hollow plates 400i- ⁇ are separated from each other or from the two assembly and support panels referred to below, by free spaces 403i-7, each of these spaces being bordered by a pair of long spacers, such 4562, 2 mm thick and 2 cm wide, resting on the two chassis beams.
• the entrances, such as 4573, of these inter-plate spaces 403 are visible in FIG. 13, however their exits are hidden.
• the assembly formed by the hollow plates 400i-6 thus suspended and stretched, by the inter-plate spaces 4032-6 and by the two free spaces at the ends, bordered by long spacers, such as 4562 and 4567, is assembled by two rigid panels (not shown) connected by means of tie rods.
• the arrows 460, 462 and 464 represent the upward air flow in the three stages of the treatment chamber 401, namely in the low chimney 426, inside the hollow plates 400 and in the high chimney 436.
• the arrow 466 represents the air flow along the walls of the active monobloc heat exchange element 438 and the arrow 468, this current in the collecting space 443 of the upper stage of the treatment chamber.
• the arrow 470 visible through the tear off 472, practiced in the rear panel of the sheet 402i, represents the downward air flow in the inter-plate spaces 403.
• the arrows 474 they represent the air streams leaving these inter-plate spaces 403 and entering the collecting space 432 of the lower stage of the treatment chamber.
• the arrow 476 represents the air current which enters the low chimney 426 of the chamber 401.
• the arrows 478, 479, 480 represent the current of sea water to be distilled which enters, passes through and leaves the active element d 'heat exchange 438. Thanks to these arrangements, this still according to FIG. 13, with diffusion of vapor and incondensable heat transfer gas, circulating by natural convection, operates in exactly the same conditions as the still of FIG. 6.
• the new hollow plate model, flat, thin and flexible, used there are better all the functional advantages of the one-piece distillation heat exchanger, according to the present invention, referenced 250 in FIG. 10A.
• a set of hollow plates 400 has the same distillation heat exchange surface per unit volume, ie 400 m 2 per cubic meter, as a set of monoblock distillation exchangers, but in addition the thickness of the walls of these plates and their hydrophilic coating is more than three times lower than that of these exchangers (0.15 instead of 0.50 mm). This considerably improves the QA / ratio to be taken into account in calculating the QE of the still, which then reaches the high value 297 indicated above.
• the manufacturing price of the main component of this new model of hollow plates 400 i.e., the thin sheet 402, its hanging rod 404, its tension bar 406 and its spacers 450
• This heat recovery block includes two groups of thin auxiliary hollow plates, provided with hydrophilic coatings, installed vertically.
• the total area of the auxiliary plates of a heat recovery block is approximately ten times smaller than that of the plates of the distillation block with which it is associated. This ratio is an inverse function of the efficiency coefficient of the heat exchange produced by these auxiliary plates.
• These auxiliary plates are rigid and adapted to withstand without deformation the hydrostatic pressures of the distilled and concentrated liquids which must circulate there.
• these are rigid cellular panels, of the kind described above by way of a variant of the flexible panels 140i-3 of FIG. 7, provided with connection washers 172 and 174.
• These washers form sections of conduit d 'supply, assembled by tie rods such as that referenced 186 in Figure 8.
• the end 184 of the lower supply duct of each group of auxiliary plates constitutes the inlet of this group, connected to the suction pipe of a siphon, and the end of its high duct, the outlet of this group connected to the drain pipe of this siphon.
• the heat recovery block formed by these two groups of auxiliary plates and by the pipes of their siphons are not shown, so as not to overload the drawing and because these pipes are common components, added to original components, perfectly described and represented elsewhere.
• the hollow plates of this heat recovery block have the same length and width as the hollow plates of the distillation block, and they also have inter-plate spaces with lateral edges, sealed by spacers. These two blocks are joined and their components are clamped and clamped by rigid end panels, connected together by tie rods.
• Seawater preferably at a temperature as low as possible (for example, cooled by natural means or, failing that, at Tu rather than Tb), is spread on the coverings of the two groups of auxiliary hollow plates and part of the air stream at temperature T4 flows from top to bottom along these coatings.
• the two suction pipes of the siphons respectively plunge into the gutter 416 for collecting distilled water and into the tank 434 for collecting concentrated brine and they are connected to the inlets of the two groups of plates of the heat recovery block.
• the two evacuation pipes of these siphons are connected to the outlets of these auxiliary hollow plates and these evacuation pipes open at a good distance below the levels of the gutter 416 for one and of the reservoir 434 for the other.
• the hot liquids which circulate from bottom to top in these auxiliary hollow plates cause the evaporation of part of the sea water spilled on their coatings.
• the streams of cooled air which circulate from top to bottom along these coatings carry away the vapor thus produced and, on this occasion, heat up and saturate.
• the two saturated hot air streams, which leave the inter-plate spaces of these two groups of hollow heat recovery plates, are added to those which leave the inter-plate spaces of the hollow distillation plates.
• the mixture is then reheated and supersaturated and it takes the temperature Ti. Under these conditions, the temperatures of the distilled and concentrated liquids discharged are relatively low, of the order of 40 ° C., ie 15 ° C. above the usual temperature Tu of the liquid to be distilled. In the usual case where the quantities of distilled water and brine produced are equal, this results in causing the general COP of the still to rise to 20.
• a family solar still with saturated hot air circulating by natural convection which includes (1) a solar boiler having 1 m 2 of greenhouse, which produces 7 kWh thermal per day, (boiler 120 'of fig.6) installed in place of the heating tube 422 of f ⁇ g.13, (2) a laminated distillation block, formed of 100 thin hollow plates, flexible and flat, (400 plates of 20 dm 2 per side and a pitch of 4.5 mm) and (3) a heat recovery block formed of ten auxiliary hollow plates, can produce 200 liters of distilled water per day.
• each block comprising 500 hollow distillation plates and 50 recovery plates, identical or similar to the plates 400 of fig. 13 (each of 1 dm 3 of active volume), one can build a still for small communities which will have (with a COP of 20) a production of distilled water of approximately 20 m 3 per day.
• An identical production of distilled water can be provided by a still provided, on the one hand, with a distillation block of 2,000 tensioned flat hollow plates, of 1 m 2 of surface per side, a step of 4.5 mm and 10 m 3 of total active volume and, on the other hand, a solar boiler equipped with a greenhouse of 100 square meters, producing around 700 kWh per day.
• a still associated with an average boiler of 350 kW, which produces about 200 m 3 / day.
• Such a boiler could be the heat exchanger for cooling the diesel engine of a small power plant or a ship.
• Fresh water production of a few thousand m 3 / day is possible with a saturated hot air still, circulating by natural convection, comprising a boiler of a few tens of MW, feeding in parallel the heating tubes of several distillation blocks , with a total active volume of a few hundred cubic meters, provided with as many heat recovery blocks having a few tens of cubic meters of active volume.
• the effectiveness of the stills according to the invention results from the maximum use of the heat which is supplied to them, which requires, beforehand, an optimal insulation of their treatment chamber.
• thermal insulation will generally be carried out on site, by means of local construction (adobe, for example).
• the outer wall of the still will be a thin panel, delimiting the relatively sealed enclosure of the still.
• thermosiphon In the case where the still with diffusion of steam and counter-current of water, according to figure 3, could not, for practical reasons of installation, function by thermosiphon, a pump will be used to ensure the circulation of the heat-transfer liquid .
• the heat exchanger 80 constituted by the coaxial conduits 318 and 320 of FIG. 12B can be replaced by a simple monobloc heat exchanger 250 or 438.
• the flat hollow plates 400, thin and flexible, with stretched walls, of FIG. 13, can obviously be used to constitute the distillation block of a still according to FIG. 5.
• a still with natural convection and solar boiler according to FIG. 6, provided with a reservoir 63 ′ for collecting hot brine, ensuring it a complementary operation at night, only the distilled water produced will be the object of thermal recovery.
• high and low chimneys of significant heights are necessary to generate this natural convection in a satisfactory manner and thus obtain an adequate transit time t in the hollow distillation plates. Such heights may be inappropriate for a family still.
• the heating tube 422 described in fig. 13 and its supply (which is a device generally absent kitchens) will advantageously be replaced by a particular hot spring, easy to build in an apartment kitchen or on a pleasure boat.
• this hot spring which will also have a complementary propellant function, will be constituted by a heating tube, producing steam jets, installed like tube 422.
• This tube will have a small internal diameter (2 cm, for example), it will be closed at one end and provided with calibrated orifices, drilled at regular intervals (5 cm, for example) along a generator.
• This tube will be installed at a good distance upstream from the inlets of the hollow plates, so that the jets of vapor which it produces are, on the one hand, correctly directed and, on the other hand, capable of dispersing in the current of gas before it enters the hollow plates.
• These steam jets will, for example, have a temperature of 101 ° C. and a pressure just slightly higher (40 hPa) than atmospheric pressure. They will be ejected at a speed of 110 m / s.
• these jets of steam will produce an upward thrust, complementary to that generated by natural convection and, if necessary, the downward thrust produced by the propeller of a fan.
• a steam jet heating tube can, (as a complementary hot source, operating whenever necessary) be installed upstream of the inlets of the hollow plates, when the still has a solar boiler. such as that referenced 120 'in fig. 6.
• the steam which will feed this steam jet heating tube will be produced, in complete safety, by a simple kettle connected to this tube by an insulating pipe.
• This kettle will contain distilled water and it will be heated by any heating means available in the kitchen or, more generally, in the vicinity of the still.
• the kettle will be a pot provided with a lid, adapted to be fixed to it in a sealed manner.
• This cover will include a water intake and a steam intake, intended to be connected by a hose to the free end of the steam jet tube.
• the water intake will be extended by a conduit, terminated by a needle valve fixed to a float (similar or equivalent to that 356-358 in Figures 11 and 12), so that this pot can operate at a constant level.
• the water intake of this kettle will be supplied by a tube open to the open air (similar to the tube 113 'in Figure 6), connected to the outlet gutter of the still and provided with a weir, opening out above a reserve of 'distilled water.
• the amount of distilled water consumed by the kettle will decrease the COP of the still by one point. However, this is of little importance, with a still according to the invention, such as that described in FIG. 13, which generally has a COP of at least 15.
• This solution can obviously also be applied to stills for communities, of much higher power, and this steam jet heating tube can then be used alone or in combination with another hot source.
• Such a family still, provided with both relatively short upper and lower chimneys, a tube with calibrated orifices producing jets of steam and, where appropriate, a fan, constitutes a household appliance of reduced size, producing distilled water at attractive economic conditions.
• a tube with calibrated orifices producing jets of steam and, where appropriate, a fan constitutes a household appliance of reduced size, producing distilled water at attractive economic conditions.
• Such a device is particularly well suited to equipping pleasure boats and the kitchens of apartment buildings in certain large modern coastal cities (such as Hong Kong or Singapore), where there is a continuous shortage of fresh water and where, to cope with this chronic insufficiency, sea water is also distributed to supply toilet flushes.
• the noncondensable gas, used in a steam diffusion still may not be pure air but a mixture of air and a gas capable to perfect the elimination of the infectious germs which the water to be distilled could contain entering a steam diffusion still according to the present invention. Indeed, measurements, carried out in an official laboratory, proved that a distillation, carried out by means of such a still, could transform into drinking water, the polluted water resulting from a treatment by lagoonage of wastewater from an average town.
• the invention relates mainly to processes and apparatuses for the production of fresh water, from sea water, brackish water or polluted water, it also concerns the food and chemical industries, for producing concentrated liquids , such as syrups or brines. It is in fact particularly advantageous to recover the thermal energy from the hot effluents of the factories concerned, in order to save significant costs of evaporation of the various liquids to be concentrated.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Heat Treatment Of Water, Waste Water Or Sewage (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=33443187

Family Applications (1)

Country Status (7)

Families Citing this family (33)

Family Cites Families (7)

• 2003
  • 2003-06-06 FR FR0306838A patent/FR2855766A1/fr active Pending
• 2004
  • 2004-06-03 AU AU2004247437A patent/AU2004247437A1/en not_active Abandoned
  • 2004-06-03 US US10/559,696 patent/US20060272933A1/en not_active Abandoned
  • 2004-06-03 EP EP04767241A patent/EP1636138A2/de not_active Withdrawn
  • 2004-06-03 WO PCT/FR2004/001373 patent/WO2004110936A2/fr active Application Filing
  • 2004-06-03 CA CA 2528244 patent/CA2528244A1/fr not_active Abandoned
• 2005
  • 2005-12-05 IL IL172367A patent/IL172367A0/en unknown

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events