WO2012104662A2 - Dessalement de faible enthalpie en plusieurs étapes - Google Patents

Dessalement de faible enthalpie en plusieurs étapes Download PDF

Info

Publication number
WO2012104662A2
WO2012104662A2 PCT/GR2012/000002 GR2012000002W WO2012104662A2 WO 2012104662 A2 WO2012104662 A2 WO 2012104662A2 GR 2012000002 W GR2012000002 W GR 2012000002W WO 2012104662 A2 WO2012104662 A2 WO 2012104662A2
Authority
WO
WIPO (PCT)
Prior art keywords
stage
vacuum
desalination system
condensers
stage desalination
Prior art date
Application number
PCT/GR2012/000002
Other languages
English (en)
Other versions
WO2012104662A3 (fr
Inventor
Emmanuil Dermitzakis
Aristeidis Dermitzakis
Original Assignee
Emmanuil Dermitzakis
Aristeidis Dermitzakis
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Emmanuil Dermitzakis, Aristeidis Dermitzakis filed Critical Emmanuil Dermitzakis
Publication of WO2012104662A2 publication Critical patent/WO2012104662A2/fr
Publication of WO2012104662A3 publication Critical patent/WO2012104662A3/fr

Links

Classifications

    • 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
    • B01D3/10—Vacuum distillation
    • B01D3/103—Vacuum distillation by using a barometric column
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/0011—Heating features
    • B01D1/0029—Use of radiation
    • B01D1/0035—Solar energy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D1/00—Evaporating
    • B01D1/26—Multiple-effect evaporating
    • 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
    • B01D3/06—Flash distillation
    • B01D3/065—Multiple-effect flash distillation (more than two traps)
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B01D5/0033—Other features
    • B01D5/0036—Multiple-effect condensation; Fractional condensation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
    • B01D5/0033—Other features
    • B01D5/0048—Barometric condensation
    • 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
    • C02F1/046—Treatment of water, waste water, or sewage by heating by distillation or evaporation under vacuum produced by a barometric column
    • 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
    • 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
    • Y02A20/212—Solar-powered wastewater sewage treatment, e.g. spray evaporation

Definitions

  • the invention relates to a multi-stage system for efficient desalination of saline or brackish water by using low-enthalpy heat, for the successive vaporizations of which it exclusively employs passive vacuum generated and maintained by application of natural forces, such as atmospheric pressure and gravity.
  • natural forces such as atmospheric pressure and gravity.
  • the low pressure (vacuum) in the expansion chamber is achieved exclusively by gravity (passive vacuum) , and no further use of conventional energy is required for the generation and maintenance of the low pressure.
  • the atmospheric pressure corresponds to the hydrostatic pressure developed by a ca. lOm-high water column, if a column having a height more than 10 m and closed at the upper end is filled with water and left to drain due to gravity into an open vessel, the water will withdraw to generate a passive vacuum in the tube and maintain a ca. lOm-high hydrostatic column, depending on the temperature and the ambient barometric pressure.
  • EP 2 248 568 A which relates to a method having stages connected in series and arranged one next to the other on the same horizontal level.
  • the procedure is separated into many steps/stages where sea water is heated by an external source to the highest temperature of the system and expanded successively and violently from the first and hotter stage to the last and cooler one, accompanied by steam formation and a simultaneous and progressive temperature drop.
  • the hot seawater at the temperature of a previous stage is introduced in the next stage and in an area of lower pressure, where the new steam is again produced violently due to the progressive pressure drop from stage to stage, etc.
  • Each stage comprises two barometric columns having a height of at least 10 m, one of which (the condensates column) ends in an open condensates vessel, which is - especially for this technology- not a simple shallow vessel, but also of a height of at least 10 m.
  • Initiation of operation in order to generate the initial passive vacuum, is effected by conventionally filling all the plant with water and subsequently draining thereof, leaving behind a vacuum. Since however each stage must be filled and drained separately, it constitutes a particularly complex, expensive, and time- consuming system, in which a very large number of valves and pumps must be activated and coordinated for each stage.
  • the other method requires independent conventional pumps in each concentrates removal stage, which again require an increased installation and operation cost, and also eliminate a significant part of the ecological character of the method.
  • the steam is substantially entrapped in a specific pouch in the part of a reversed U, after and below the exchanger-condenser, in other words in a position which does not favour the motion of the steam towards the exchanger-condenser, thereby reducing the efficiency.
  • the hydrostatxcally generated passive vacuum can not extract the non-condensable gases, such as the air entering through sealing failures on the extended and complex structure of the plant.
  • these non- condensable gases selectively remain on the surfaces of the condensers, thereby reducing their efficiency, while at the same time due to the volume they permanently occupy in the space of the chambers of the stages, they increase the pressure and degrade the vacuum.
  • the solutions proposed by the above technology include a supplementary use of conventional vacuum pumps and the interruption and re-initiation of the operation of the plant .
  • the principle of operation of the system is based on the violent/flash boiling of a solution or seawater which has been heated to a temperature slightly lower than the boiling point under a specific pressure and subsequently introduced in an environment/chamber of lower pressure, where as it is known evaporation occurs at a lower temperature.
  • a hot source emitting heat of low enthalpy and temperature is employed, such as solar energy, geothermal energy, heat discharged from energy power plants, etc., and mild renewable energy systems in general.
  • the procedure is divided in many steps/stages, and the steam produced in each stage is condensed in the same stage by the supply water counter-flowing in respect to the brine from the last, cooler stage to the first, warmer stage, while at the same time a progressive preheating of the supply water by the latent heat of condensation occurs.
  • the temperature difference between the hot source and the supply-cooling water is split into a large number of individual steps, approaching an ideal heat recovery, thus the temperature of the brine rejected is almost equal to the temperature of the supply-cooling water at the inlet.
  • the multi-stage character of the method and the temperature stepping-up minimize the increase in the entropy of the system and increase the efficiency of the plant.
  • the operation of the system also requires a respective stepping-up of the pressure in the various steps/stages, the pressure in a stage being smaller than the minimum pressure in the preceding stage so that the boiling point of the brine moving from stage to stage is incrementally decreased.
  • Each stage constitutes a separate evaporator with an evaporation chamber, a condenser, and a spacious perpendicular connecting air duct. All the stages are connected in series. In order to keep the required pressure difference between the stages, hydrostatic pipes having a U-shape and a height corresponding to the pressure difference are employed.
  • All the condensers are arranged in succession and preferably peripherally at the higher level of a tower, whereas the respective evaporation chambers are correspondingly arranged precisely below them at lower levels and at elevations lying progressively lower in relation to the higher level of their condensers.
  • the height of the perpendicular connecting air ducts is progressively and constantly increased, following the peripheral, helical arrangement of the evaporation chambers below their respective condensers.
  • the incremental variation in the elevation difference of the evaporation chambers from stage to stage additionally facilitates the motion of the brine.
  • the stages as a whole are split into a plurality of equal groups, resulting to a plurality of arrangement levels of the respective condensers, wherein the second, third etc. level is located at an elevation lower than the preceding one.
  • These new levels-platforms will serve as a base for the peripheral arrangement of the respective condensers, as well as subsequently for the helical arrangement of their evaporation chambers.
  • the whole quantity of desalinated water and the rest of the brine are respectively accumulated in the condensers and in the evaporation chamber of the last stage, from where they are extracted through two independent vertical hydrostatic/barometric columns of significant height (more than 10m) , which end into two shallow open vessels, the ends of the columns being immersed below the water level.
  • the plant For the initiation of the operation, the plant is filled with water and left to drain, leaving behind a vacuum which is preserved and maintained throughout the operation due to the two significantly high hydrostatic columns which are arranged at the ends of the last stage of the plant.
  • This vacuum is the passive vacuum of the productive procedure of the evaporators, which communicate with the vacuum area of the vertical columns, and no additional outer conventional energy, or pump, or ejector (which employs, as auxiliary medium, steam, or liquid under conventionally generated pressure) is required for the generation and maintenance of the vacuum.
  • vacuum ejectors which operate on the basis of the Venturi principle, by the use as auxiliary medium the descending water of the columns, which generate a dynamic vacuum that communicates with and preserves the passive vacuum generated in the spaces of the evaporators, removing: a) the non-condensable gases and b) balancing any leakages (introduction of air) due to sealing failures.
  • valves which automatically and analogously adjust the cross-section of the water outlet, the valves cooperating with sensors detecting the pressure, level and supply of water .
  • the stepping-up of pressure (degree of vacuum) required in each stage and beginning from the almost absolute, single passive vacuum initially generated and established in all the spaces of the evaporators, is preferably achieved by the progressively increase, from stage to stage, of the total volume of the evaporator of each stage.
  • This total volume includes: a) the evaporation chamber, b) the condenser and c) the connecting air duct, the hottest first stage (with the lowest vacuum) having the smallest volume and the coolest last stage (with the highest vacuum) having the largest volume.
  • Additional contributory factor to the pressure stepping-up is the dynamic vacuum generated at the ejectors of the downward columns.
  • the dynamic vacuum acts via its ducts and via independent valves communicating with the initial passive vacuum and with all the evaporators.
  • the positioning of the condensers at highest points of the plant creates an additional elevation difference, thereby achieving higher levels of dynamic vacuum and conditions for additional energy exploitation, while the vertical arrangement is space-saving, especially in cases where the desalination plant will be installed within an already operating energy production plant, the thermal waste of which the plant will exploit. It also allows elevation differences between the evaporation chambers, an exploitation of the brine fall, etc.
  • the present invention also aims at reducing the cost and at increasing the efficiency of thermal energy- production plants with parallel production of desalinated water, since renewal energy forms, low enthalpies and temperatures, as well as rejected energy of any form are used.
  • Figure 1 A diagram of the operation of a single- stage desalination tower of the present invention, which uses solar energy.
  • FIG. 1 A detail of figure 1.
  • Figure 3 A cross-section of a multi-stage desalination tower using solar energy with the successions of condensers being peripherally arranged on two parallel levels at the top of the tower.
  • Figure 4 A plan view of the highest level of the tower of figure 3 with the first and highest succession of peripherally arranged condensers.
  • FIG. 5 A cross-section A-A of the next level of the tower of figure 3 with the second succession of peripherally arranged condensers.
  • Figure 6 A diagram of the operation of a multistage desalination tower using solar energy with the successions of condensers on two parallel levels.
  • Figure 7 A detail of the successive arrangement of the stages with the incremental increase in the elevation difference of the evaporation chambers from the single level of the condensers.
  • FIG. 1 The operation principle of the system in its single- stage variation with a flat solar collector of low enthalpy as heat source is shown in figure 1 and is based on the violent/flash boiling of a solution/seawater heated to a temperature slightly lower than the boiling point that corresponds to a specific pressure, and subsequently introduced in a chamber exhibiting lower pressure where evaporation takes place at a lower temperature.
  • the basic element of the method, the single stage, or evaporator li consists of a condenser Ci with exchanger 35 and an evaporation chamber e lf which are arranged at the upper level of a tower 40 and communicate between them via the spacious perpendicular air duct 2 ⁇ .
  • the stage constitutes an autonomous evaporator 1 ⁇ .
  • two vertical columns 6 and 7 having a height H of ca. 10m extend and end into the interior of the intermediate open vessels 8 and 9 for the brine and the desalinated water respectively.
  • the ends of the columns are permanently located below the water level of the vessels so that the hydrostatic column created due to the low pressure (vacuum) established in the evaporator 1 ⁇ is maintained permanently and at the same height H.
  • the brine and the desalinated water are extracted via another pair of vertical columns 10 and 11, respectively, having a significant height H x and H 2 respectively.
  • the vacuum ejectors 12 and 13 are respectively installed, employing the descending water as auxiliary medium, which discharge into the final vessels 14 and 15, similar to the respective ones 8 and 9, which additionally communicate with the atmosphere.
  • the whole system until the final vessels is airtight and thermally insulated.
  • the system In order to initiate the operation of the system and to generate the required vacuum in the evaporation chamber ei, the condenser ci and the evaporator 1 ⁇ in general, the system is filled with water completely and then allowed to drain, whereas for saving reasons both the seawater and the desalinated water are employed. Each of these two media fills only the respective parts in the plant which each occupies during normal operation.
  • the desalinated water is deviated from the extraction duct 28 to the duct 22 and fills the column 7 from the valve 24, closed during this phase, at its end until the whole space of the condenser Ci.
  • pump 3 of the seawater fills the seawater network from the end of the air duct 2i and the evaporation chamber ei until the valve 25, closed during this phase, at the end of the column 6. It is apparent that, during filling, air extraction valves at the higher points will also be used (not shown) .
  • the plant is allowed to drain by gravity and by opening the valves 24 and 25 into the respective open vessels 8 and 9.
  • the water will withdraw maintaining permanently the two hydrostatic columns of height H (ca 10 m) , and leaving behind a permanent passive vacuum p a .
  • FIG. 2 shows exemplarily, in two phases, a special nonreturn valve 27 with floater for the automatic closing of the end of the air duct 2 ⁇ that connects the areas of seawater and desalinated water.
  • the dashed line depicts the open valve, i.e. in normal-operation position.
  • the generation of the initial passive vacuum may also be achieved more simply if desalinated water is exclusively used, making the arrangement of the nonreturn valves 27 redundant.
  • conventional vacuum pumps may be used to generate the initial vacuum in the plant, or vacuum ejectors may be additionally installed and used on the conventional pumps 3, 20, 21 of the networks (not shown) .
  • seawater at ambient temperature is conveyed via the pump 3 and the supply duct 4 to the single condenser ci with exchanger 35 after having been intermediately reheated in the heat recovery exchangers hi, h 2 .
  • a specific pressure p 0 is also established, which is maintained by the valve 30 at its outlet.
  • temperature t D is selected to be slightly lower than the boiling point corresponding to the pressure p 0 , the water does not evaporates in the space of the collector before the valve 30, but upon entering and expansion via the valve 30 in the evaporator 1 ⁇ and in the evaporation chamber e ⁇ of the system, where initially the just-formed high passive vacuum p a (almost absolute) is established. Subsequently, violent/flash boiling of a large quantity of the warm solution/seawater occurs since as known vaporization takes place at a much lower temperature if a lower pressure p a (high vacuum) is established.
  • the warm solution/seawater will lose temperature due to vaporization of a large part thereof, the temperature finally reaching a value ti significantly lower than t 0 , while the pressure in the evaporator will reach after vaporization an intermediate value pi. It applies:
  • the generated warm vapors ascend into the space of the condenser ci via the duct 2i, due to the vapour pressure on the surface of the brine in the evaporation chamber ei, after passing through a separator which retains and removes brine droplets (not shown) .
  • the vapors condense due to the temperature difference in relation to the supply seawater flowing via the pump 3 and the duct 4 (in a direction opposite to that of the brine) into the exchanger 35 of the condenser ci .
  • the temperature of the supply seawater is increased due to the latent heat of condensation of the vapors.
  • the desalinated water produced is accumulated at the bottom of the condenser ci, falling due to gravity via the vertical column 7 into the open vessel 9, after recovery of its heat by the heat exchanger h 2 to preheat the ascending supply seawater. From the overflow of the vessel 9, the desalinated water flows due to gravity in the vertical column 11 and the vacuum ejector 13.
  • the brine flows from the evaporation chamber ei via the exchanger hi and column 6 into the open vessel 8 and from the overflow thereof into the column 10 and then the vacuum ejector 12 and the vessel 14.
  • the ejectors 12 and 13 operate on the basis of the Venturi principle, the descending water of the vertical columns 10 and 11 being the auxiliary medium, and generate a dynamic vacuum which via the air ducts 16 17, 38a and 38 communicates with and preserves the passive vacuum that has already been generated in the space of the condenser Ci, the evaporation chamber ei and the evaporator li in general, as well as of the vertical air ducts 6, 7, removing: a) the non-condensable gases, and b) the air flowing in the evaporator through sealing failures. These gases, due to the volume they permanently occupy in the evaporator, increase the pressure and degrade the vacuum that should be present for the normal operation of the system.
  • the air ducts 16, 17 have nonreturn valves 18 and 19 in order to prevent any undesired returns and degradations of the passive vacuum already in the system.
  • the ejectors are substantially responsible for the maintenance of the vacuum during operation of the plant, since only in this case there is a downward flow of fluid products. It constitutes a production of a dynamic vacuum for maintaining the operation rather than initiating that.
  • connection between vacuum air ducts 16 and 17 may be parallel, or in series, and by means of regulating valves .
  • Ejectors for additional vacuum production may also be arranged at the ends of the vertical columns 6 and 7 after valves 25 and 25 (not shown) .
  • the ejectors 12 and 13 may otherwise by multi-stage ones in order to achieve a higher vacuum or these may also be connected between them in parallel or in series, depending on the needs and the value of the initial passive vacuum (not shown) .
  • the intermediate open vessels 8 and 9 along with the respective intermediate vertical columns 6 and 7 having a height H may be removed.
  • H the height they occupy will be exploited by the columns 10 and 11, which will be respectively elongated, and each will now have a total height that will be higher by the value H, i.e. Hi+H and H 2 +H respectively (not shown) .
  • the speed of water in the downward columns should be controlled by a suitable combination of: a) the outlet cross-sections and the cross-sections of the vertical columns 7, 11 and 6, 10, b) the temperatures of the desalinated water and the brine respectively to control the size of the negative pressures generated by the flow in these vertical columns, so that the vapour pressure of the descending fluids is not exceeded which would cause an interruption in the continuity of their columns.
  • valves 42 which automatically and analogously adjust the cross- section of the water outlet, in cooperation with sensors detecting the water pressure, level and supply.
  • the brine and the desalinated water are removed to the collectors of the seawater and desalinated water via the pumps 20 and 21 and the ducts 43 and 28 respectively.
  • Figures 3, 4, 5, 6, 7, depict the cross-sections, plan views, the operation diagram and the details of a desalination tower using low-enthalpy solar energy, which constitutes the multi-stage variation of the previous single-stage system of figures 1, 2.
  • the same symbols and terminology are used as in the respective single-stage system in order to show the full correspondence between them.
  • an extended, preferably circular, surface is configured, at the periphery of which the stages of the multi-stage desalination are arranged.
  • it is a plurality of evaporators/stages l v connected in series.
  • Each stage l v consists of a condenser c v at the upper part and an evaporation chamber e v at the lower part, which communicate between them via a spacious vertical air duct 2 V , and the whole stage constitutes a separate and isolated evaporator.
  • All the condensers are located and arranged as a succession and preferably peripherally at the highest level La of the tower 40, whereas the respective evaporation chambers are arranged precisely below them at lower levels and at elevations lying progressively lower in relation to the level La.
  • the height of the perpendicular connecting air ducts 2 V is progressively and constantly increased, following the peripheral and simultaneously helical arrangement of the evaporation chambers below their condensers.
  • the elevation difference of the evaporation chambers from the common level La of the condensers is also increased.
  • the exchangers 35 of the condensers c v are connected in series between them, whereas the condensates are conveyed from condenser to condenser via the U-shaped pipes 36 at the bottom, which also serve in sealing the successive condensers between them where as known the different pressures of the evaporators/stages are established.
  • L 0 the constant elevation difference between two successive evaporation chambers, this serves in the convenient and unobstructed transfer of the remaining, non-evaporated brine to the next stage via the ducts 37.
  • the duct 37 descends with a tilt towards the next evaporation chamber and ends to a U-shaped pipe having a height of H 5 in order to ensure again the sealing/isolation of the stages and the maintenance of the progressive stepping-up of the pressures, a necessary condition for the multi-stage character of the method.
  • the group of stages/evaporators is separated in two semi-groups and two levels La and Lb are provided for the condensers, the second level, Lb, being created at an elevation lower by the height H a , and serving as a base for a respective peripheral arrangement of all the condensers of the second semi-group of stages. It is understood that the evaporation chambers of the second semi-group will have a respective peripheral arrangement below their condensers, the elevation difference from their new reference level Lb being respectively and constantly increased from stage to stage by the same height L 0 as in the first semi-group of stages.
  • the two semi-groups of stages will be connected in series between them and this regards both the condensers and their evaporation chambers. It is obvious that more than two divisions on the whole group of stages may be obtained.
  • the whole system of stages is airtight and thermally insulated.
  • a specific pressure p 0 is also established which is maintained constant, being controlled by the valve 30 at its outlet. At this temperature and pressure, the water is introduced in the first stage li.
  • the temperature t D is selected to be slightly lower than the boiling point corresponding to the pressure p 0 , the water does not evaporate in the space before the valve 30, but does so as soon as it enters and expands via the valve 30 in the evaporation chamber ei of the first stage li, where a pressure pi is established that is lower than p 0 (pi ⁇ P o ) ⁇
  • p 0 pi ⁇ P o
  • a single high passive vacuum is initially established in all the spaces of the system, which is ensured by the connection of the spaces to the common collecting air duct 38, and which is exhibited by the very low pressure p a , the lowest of the system.
  • the high vacuum, or the initial low pressure p a is generated as in the single-stage variation described in figures 1,2, i.e. by filling with water and then draining all the plant (as appropriate) .
  • the multi-stage variation and operation requires a stepping-up of the temperatures and pressures in the evaporators/stages, the first one li having the highest temperature ti and highest pressure pi (relatively low vacuum) , and the n-th one l v having the lowest temperature t v and lowest pressure p v (very high vacuum) .
  • This necessary stepping-up and progressive increase in pressure (with a respective reduction in vacuum) from the initial and highest, almost absolute vacuum (or the very low pressure p a ) , to the relatively low vacuum (or the highest pressure pi) of the system, is preferably achieved by the progressive increase in the total volume of the evaporators/stages from the first li to the n-th l v .
  • the term "total volume" of an evaporator/stage means the sum of the volumes of: a) the evaporation chamber e v , b) the condenser c v , and c) air duct 2 V connecting these.
  • ⁇ and ti depend on: a) the state of the liquid, which is characterized by the values of p 0 and t 0 , b) the pressure p a and the temperature previously established in the space after the valve 30, and c) the total free volume that is available for the vaporization of the introduced liquid.
  • a contributory factor to the progressive increase in the free volumes of the evaporators/stages and thus to the progressive variation in vacuum is also the progressive increase in the height L v of the air ducts 2 V from the first l v to the n-th l v .
  • the warm solution/seawater will lose, due to evaporation of a significant portion thereof in the first stage, temperature which will be reduced as already mentioned from t 0 to ti, whereas the warm vapors generated ascend in the space of the condenser ci via the duct 2i, after passing through a separator to retain and remove brine droplets (not shown) .
  • the vapors are condensed due to the temperature difference in relation to the supply seawater flowing via the duct 4 in the opposite direction to the brine in the exchanger 35 of the condenser Ci, having passed through all the condensers of the other stages beginning from the n-th l v .
  • the temperature of the supply seawater is increased by the gaining the latent heat of condensation of the vapours.
  • the desalinated water produced accumulates in the bottom of the condenser c lr and is conveyed from one condenser to another via the U-shaped pipes 36 at the bottom, which also serve in sealing/isolation of the successive condensers between them, since different pressures are established.
  • the height of the U-shape of the pipe 36 is respective to the pressure difference established between stages.
  • the duct 37 descends with a tilt towards the next evaporation chamber e 2 and ends to a U-shaped pipe having a height H 5 , so the sealing/isolation of the stages and the maintenance of the specific pressure differences are also ensured.
  • the total number of stages is divided in two semigroups for operational reasons and two levels La and Lb will be provided for the condensers c v , the second one, Lb, being arranged at an elevation lying lower by the height H a , and serving as base for a respective single peripheral arrangement of all the condensers of the second semi-group of the stages.
  • the desalinated water produced by the whole stages of both levels La and Lb descends by gravity through the vertical columns 7 a and 7 b having a height H of ca. 10m, which end in the interior of the intermediate open vessels 9 a and 9 b respectively, after its heat has been recovered by the exchangers h 2a and h 2b , to preheat the ascending supply seawater.
  • the ends of the columns are permanently located below the water level in the vessels, so that the hydrostatic column created due to the established vacuum is maintained permanently and at the same height.
  • the desalinated water flows again by gravity in the vertical columns ll a and ll b having a significant height H 2a and H 2b a d in the vacuum ejectors 13 a and 13 b which end in the common open vessel 15.
  • Respectively the remaining brine flows from the evaporation chamber e v of the last stage l v to the open vessel 8 via the exchanger hi and the column 6 which has a height H of ca. 10m. From the overflow of the vessel 8, it descends in the column 10 having a significant height Hi and in the vessel 14, after passing through the vacuum ejector 12 at the end of the column 10.
  • the dynamic vacuum generated in the ejectors removes via the air ducts 16, 17 a and 17 b and the basic common collecting vacuum air duct 38, continuously and permanently, the gases which are contained in the supply water, released during vaporization and remain uncondensed, as well as the air flowing in the network through sealing failures. These gases selectively remain on the surfaces of the condensers, reducing and degenerating their efficiency, while in parallel due to the volume they permanently occupy in the evaporator they increase the pressure and degrade and degenerate the degree of vacuum.
  • the air ducts have non-return valves 18, 19 a and 1% in order to prevent undesired returns and degradations of the passive vacuum which is already established in the evaporators/stages and with which they permanently communicated via the collecting air duct 38.
  • the connection of the basic collecting air duct 38 of the vacuum with the evaporators/stages, and the final adjustment of the specific vacuum to be maintained, are achieved by the valves 41 for each stage independently.
  • Some of the vacuum air ducts (16, 17 a and 17 b ) may also be connected to their independent collecting air duct, other than the basic one 38, and act on only a specific group of condensers (not shown) .
  • the dynamic vacuum generated in the ejectors also contributes via the communication valves 41 to the stepping-up of the basic pressure in the evaporators/stages, parallel to the progressive increase in their free volumes.
  • the intermediate open vessels 8, 9 a and %, along with the respective intermediate columns 6, 7 a and 7 b having a height H of ca. 10m, may be removed.
  • the height H that these occupy will be filled in this case by the columns 10, ll a and li b which will be respectively elongated and will each now have a total height larger by ca. 10 meters ( ⁇ + ⁇ , 3 ⁇ 4 3 + ⁇ and 3 ⁇ 4 b +H respectively) (not shown) .
  • the water speed in the downward columns must be controlled by the suitable combination of: a) the water outlet cross-section and the cross-sections of the vertical columns, b) the temperatures of the desalinated water and the brine.
  • valves 42 are provided which automatically and analogously adjust the water outlet cross-section, in cooperation with sensors detecting water pressure, level and supply.
  • the vessels 8, 9 a and 9 b have a significant volume and surface in order to store and maintain the supply in the columns during periods of provisional instability in the production .
  • the brine and the desalinated water are removed from the final vessels 14 and 15 by the pumps 20 and 21 and the ducts 43 and 28 respectively towards the collectors for the seawater and the desalinated water.
  • the ejectors 12 and 13 a , 13 b may be multi-stage, and be connected between them in parallel or in series depending on the needs and in order to achieve the desired vacuum (not shown) .
  • Ejectors for additional production of vacuum may also be arranged at the ends of the vertical columns 6, 7 a and 7 b after the valves 25, 24 a and 24 b (not shown) .
  • the evaporation chambers may be arranged without elevation difference between them, or the condensers, instead of being coplanar, may be spirally arranged, along and parallel to the evaporation chambers, wherein the connecting air ducts have the same height and are widened (not shown) .
  • the stepping-up of the pressures from stage to stage may be achieved in combination with a progressive increase in the power of the exchangers 35 of the condensers, from the first to the n-th stage.

Landscapes

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

Abstract

L'invention porte sur un système à plusieurs étages pour le dessalement de faible enthalpie qui est constitué d'évaporateurs (lv) reliés en série constitués de condenseurs (cv) disposés sur un seul niveau au sommet d'une tour (40), leurs chambres d'évaporation respectives (ev) étant disposées à des niveaux de plus en plus bas et reliées aux condenseurs (cv) par des conduits d'air verticaux (2v) de hauteur de plus en plus grande. Le système est basé sur l'ébullition violente/éclair d'eau de mer qui a été chauffée à une température légèrement inférieure au point d'ébullition et introduite dans un environnement de plus basse pression. Du vide passif est employé, lequel est produit par application de la pression atmosphérique et de la gravité. L'augmentation de la pression par paliers (pv) est réalisée par augmentation progressive du volume des évaporateurs. L'évacuation de l'air est réalisée par le vide dynamique produit dans des éjecteurs (12, 13a, 13b) qui emploient l'eau dessalée produite et la saumure rejetée comme milieu auxiliaire.
PCT/GR2012/000002 2011-02-02 2012-02-02 Dessalement de faible enthalpie en plusieurs étapes WO2012104662A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GR20110100052 2011-02-02
GR20110100052A GR20110100052A (el) 2011-02-02 2011-02-02 Πολυβαθμια αφαλατωση χαμηλης ενθαλπιας

Publications (2)

Publication Number Publication Date
WO2012104662A2 true WO2012104662A2 (fr) 2012-08-09
WO2012104662A3 WO2012104662A3 (fr) 2012-11-22

Family

ID=46384418

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GR2012/000002 WO2012104662A2 (fr) 2011-02-02 2012-02-02 Dessalement de faible enthalpie en plusieurs étapes

Country Status (2)

Country Link
GR (1) GR20110100052A (fr)
WO (1) WO2012104662A2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016013997A1 (fr) * 2014-07-24 2016-01-28 Hse Hi̇ti̇t Solar Enerji̇ Anoni̇m Şi̇rketi̇ Système de purification d'eau à colonne barométrique
CH710735A1 (de) * 2015-02-13 2016-08-15 Thermal Purification Tech Ltd Mehrstufige Destillationsanlage, Verfahren zum Betreiben einer solchen und Steuerung dafür.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007006323A1 (fr) 2005-07-08 2007-01-18 Andreas Buchmann Installation de dessalement d'eau de mer avec un vide entretenu par la force de la pesanteur
AU2008203793A1 (en) 2008-06-17 2010-01-07 Karacanta, Oktay Mr Desalination of seawater in a vacuum tube
EP2248568A1 (fr) 2009-05-04 2010-11-10 Edwin Ebejer Système barométrique à étages multiples pour distillation de liquides à vide

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US643702A (en) * 1899-05-24 1900-02-20 Addison G Waterhouse Method of distilling and evaporating water.
US2490659A (en) * 1944-04-24 1949-12-06 Robert E Snyder Solar heated vacuum still
GB1373771A (en) * 1971-03-05 1974-11-13 Bp Chem Int Ltd Mercury recovery process
US3783108A (en) * 1971-01-18 1974-01-01 R Saari Method and apparatus for distilling freshwater from seawater
CH666473A5 (de) * 1985-09-05 1988-07-29 Atlantis Energie Ag Verdampfungseinrichtung und anlage mit solchen verdampfungseinrichtungen zum entsalzen von meerwasser.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007006323A1 (fr) 2005-07-08 2007-01-18 Andreas Buchmann Installation de dessalement d'eau de mer avec un vide entretenu par la force de la pesanteur
AU2008203793A1 (en) 2008-06-17 2010-01-07 Karacanta, Oktay Mr Desalination of seawater in a vacuum tube
EP2248568A1 (fr) 2009-05-04 2010-11-10 Edwin Ebejer Système barométrique à étages multiples pour distillation de liquides à vide

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016013997A1 (fr) * 2014-07-24 2016-01-28 Hse Hi̇ti̇t Solar Enerji̇ Anoni̇m Şi̇rketi̇ Système de purification d'eau à colonne barométrique
CH710735A1 (de) * 2015-02-13 2016-08-15 Thermal Purification Tech Ltd Mehrstufige Destillationsanlage, Verfahren zum Betreiben einer solchen und Steuerung dafür.
WO2016128455A1 (fr) * 2015-02-13 2016-08-18 Thermal Purification Technologies Limited Installation de distillation à étages multiples, procédé permettant de faire fonctionner une installation de ce type
KR20170118128A (ko) * 2015-02-13 2017-10-24 써멀 퓨리피케이션 테크놀로지스 리미티드 멀티-스테이지 증류 시스템, 그의 작동 방법
RU2690922C2 (ru) * 2015-02-13 2019-06-06 Термал Пьюрификейшн Текнолоджиз Лимитед Многоступенчатая дистилляционная установка и способ ее эксплуатации
US10427066B2 (en) 2015-02-13 2019-10-01 Thermal Purification Technologies Limited Multi-stage distillation system, method for the operation thereof
KR102503071B1 (ko) 2015-02-13 2023-02-22 써멀 퓨리피케이션 테크놀로지스 리미티드 멀티-스테이지 증류 시스템, 그의 작동 방법

Also Published As

Publication number Publication date
GR20110100052A (el) 2012-09-20
WO2012104662A3 (fr) 2012-11-22

Similar Documents

Publication Publication Date Title
Saidur et al. An overview of different distillation methods for small scale applications
US10857478B2 (en) Stacked type falling film evaporator, zero liquid discharge system comprising the same, and zero liquid discharging method using the same
AU759283B2 (en) Desalination method and desalination apparatus
US8202402B2 (en) System and method of passive liquid purification
CN100584765C (zh) 自然真空低温蒸馏海水淡化方法及装置
Choi On the brine re-utilization of a multi-stage flashing (MSF) desalination plant
AU2010366071B2 (en) Method and apparatus for desalination of seawater
US9816400B1 (en) Process and method using low temperature sources to produce electric power and desalinate water
SI2939981T1 (en) Sea water desalination apparatus and process using solar energy for continuous heat supply
AU2008276011A1 (en) Desalination using low-grade thermal energy
CN102381796B (zh) 太阳能光伏光热海水淡化一体式装置
KR101811394B1 (ko) 해수담수화장치
Maroo et al. Theoretical analysis of a single-stage and two-stage solar driven flash desalination system based on passive vacuum generation
JP2004136273A (ja) 多重熱交換真空蒸留、冷却、凍結による溶液分離及び海水淡水化の方法
EP2323743B1 (fr) Procédé d'évaporation et éventuellement de distillation de liquides au moyen d'une pompe à chaleur
US11209217B2 (en) Mechanical vapour compression arrangement having a low compression ratio
WO2012104662A2 (fr) Dessalement de faible enthalpie en plusieurs étapes
WO2001072638A1 (fr) Dispositif de dessalement
US20120267231A1 (en) System and method of passive liquid purification
CN110746024A (zh) 一种低温省煤器废水浓缩余热回用装置
CN206359270U (zh) 凝汽源热泵回热独立驱动多级闪蒸装置
CN201425434Y (zh) 一种汽液分离蒸发器
JP4261438B2 (ja) 発電及び海水淡水化システム
EP2535096B1 (fr) Système et son utilisation de désalinisation de l'eau de mer
EP3881917A1 (fr) Module pour distillation et dispositif de distillation à multiples étapes

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12730026

Country of ref document: EP

Kind code of ref document: A2