CA2190299A1 - Combined multi stage flash-multi effect distillation system with brine reheat - Google Patents
Combined multi stage flash-multi effect distillation system with brine reheatInfo
- Publication number
- CA2190299A1 CA2190299A1 CA002190299A CA2190299A CA2190299A1 CA 2190299 A1 CA2190299 A1 CA 2190299A1 CA 002190299 A CA002190299 A CA 002190299A CA 2190299 A CA2190299 A CA 2190299A CA 2190299 A1 CA2190299 A1 CA 2190299A1
- Authority
- CA
- Canada
- Prior art keywords
- brine
- msf
- reheat
- heat
- additional
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
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
- B01D3/06—Flash distillation
-
- 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)
-
- 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
- C02F1/041—Treatment of water, waste water, or sewage by heating by distillation or evaporation by means of vapour compression
-
- 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
- C02F1/06—Flash 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
Abstract
A new Multi Stage Flash (MSF) distillation system of enhanced flashing, brine reheat and superimposed Multi Effect (ME) distillation system (named herein as: Combined MSF-ME System With Brine Reheat) is disclosed. The invented system has special features designed to increase the distillation unit capacity and production rate, and improve its performance. The invented system uses a combination of: i) the up-to-date (proven design) MSF system as a base system with different methods to improve the flash chamber effectiveness (non-equilibrium factor) and flashing evaporation rate; ii) increases the MSF system flashing range through brine reheat, i.e. supply (all or part of) the brine with additional (external) heat in brine reheaters (located after the brine heater and/or within the flash chambers), and; iii)superimposes the ME distillation concept and system on the MSF base system. The invented system utilizes the mainfeatures and advantages of both MSF and ME systems simultaneously, and operates within the existing (proven design) system's constraints and limitations. The invented system allows, also, for the possibility of utilizing waste heat as the externalheat-source for brine reheat. The invented system, therefore, presents a break-through for the future generation of saline water desalination systems of higher capacity, better performance and lower water production costs.
Description
21 qO299 COMBINED MULTI STAGE FLASH- MULTI EFFECT
DISTILLATION SYSTEM WITH BRINE REHEAT
SPECIFICATIONS
Field Of The Invention This invention relates generally to saline water des~lin~tion systems and more particularly to Multi Stage Flash (MSF) and Multi Effect (ME) ~listill~tion systems.
Description Of The Previous Systems Des~lin~tion of saline water by ~istill~tion is a very effective process, because most of the chemical materials found in saline water are non-volatile at the temperaturenormally employed and hence remain in the un-evaporated brine. The two most proven distillation technologies are: the Multi Stage Flash (MSF) and Multi Effect(ME) systems. The differences between the two types of technologies are derived from the difference in the method of heat transfer. The saline water is sensibly heated in the tubes in MSF system and boiled in a thin film on the tubes in ME system. Comparisons between MSF and ME systems indicated, in general, the superiority of each systemover the other in one aspect or the other.
MSF system has proven to be the most simple, and reliable technology for producing potable water on large scale. Due to its advantages and the acc-lmul~ted operational experience gained, MSF of the recirculated flow dominates the market. MSF has the advantage that the incoming brine is heated without evaporation and fl~hing evaporation occurs without heat transfer, thus reducing the tendency for scale to form on the heat transfer surface. The significant drawback of the MSF system, as compared to other cost effective systems, are the high energy consumption (steam, pumping and other operating costs). The system production and performance can be increased (and production cost can, therefore, be reduced) by increasing the Top Brine Temperature (TBT). The TBT is limited, however, due to the high temperature hard scale deposits in the brine heater and the up-to-date antiscalent limitations.
On the other hand, ME systems are widely used in the chemical industry forthe concentration of solutions. In seawater des~lin~tion, ME has not achieved similar importance, in terms of the total installed capacities, as MSF. The ME distillation system is significantly more efficient and has a thermodynamic superiority over MSF.
The striking feature of ME system is the significant low specific power consumption as compared to MSF system.
Patent ( 8128196 ) 2 Dr. Hassan E. S. Fath ~1 qO2~q The Invention Idea The objective of the invented system (named hereas: CombinedMSF-MESystem W th Brine Rehea~) is to increase saline water distillation unit capacity, improve its performance and, therefore, reduce the fresh water production cost over the existing MSF systems. The invented combined MSF-ME system wifh brine reheat introduces the concept of increasing the MSF fl~hing range through brine reheat, and utilizes the superior advantages of both MSF and ME systems simultaneously.
The invented system uses a combination of: i) the up-to-date (proven design) MSFevaporation system as a base system with dirrele.lt methods to improvetheflash chamber effectiveness (non-equilibrium factor) and fl~hin~ evaporation rate; ii)increases the fl~hing range through brine reheat, i.e. supply (all or part ofl the brine with additional (external) heat in brine reheaters (located after the brine heater and/or within the flash chambers), and; iii) superimposes the ME evaporation concept and system on the MSF base system. Themodificationsoftheinventedsystemoverthe existing MSF system are:
a- Since additional (external) heat, for higher fl~.~hingrange and morewater production, can't be supplied before or at the brine heater in existing MSF
system (due to TBT limitations), increasing the fl~hin~ range is carried out, in the present invented system, through brine reheat; i.e. the additional (external) heat is supplied to (all or part ofl the brine after the brine heaterand/or within flash chambers.
b- In addition to increasing brine superheat from (a), other methods are considered for improving MSF flash chamber effectiveness (the non-equilibrium factor) and fl~shing evaporation rate, for additional vapor production and better system performance. This includes; increasing fl~hin~
surface area, improving brine turbulence ( brine temperature gradient), and introducing more active nucleation sites for bubbles formation.
c- The vapor generated due to: i) brine reheat (from a) ii) the improvement in flash chamber effectiveness (from b), and iii) possibly part of the main vapor generated inside the flash chambers, is then used as a source of heat to generate more vapor in the next successive stages (effects) in a way similar to the conventional ME system; i.e.theinventedsystemsuperimposestheME
evaporation concept and system on the existing MSF system designs.
The invented system increases saline water distillation unit capacity, improves its performance and reduces the fresh water production cost. In addition, the invented system operates within the existing (proven design) MSF and ME system's constraints and limitations, and allows for the possibility of utilizing waste heat as the external heat source for brine reheat. The invented system presents, therefore, a break-through for the future generation of saline water desalination systems.
Patent ( 8128196 ) 3 Dr Hassan E. S. Fath - 2l9029q.
Description Of The Invention a- MSF Base System Conf guration Figure 1 shows (for demonstration) a small unit of a typical Multi Stage Flash (MSF) distillation system of the recirculation type. The unit consists of four stages of heat recovery section and two stages of heat rejection section as shown. Seawater enters the condense tubes of the heat rejection section at the lowest temperature, Tl", and is heated up to temperature Tc5~ by condensation of the vapor generated bybrine fl~ching in the heat rejection section. At this point, much ofthe cooling seawater, mrej, is discharged from the plant for heat rejection and thebalance make-up, mr~ p, is rnixed with part of the brine flowing out of the last stage of the heat rejection section.
This mixture (at Trcc) forms the recirculated brine, mrec, and ispumped throughthe condenser tubes of the heat recovery section where it is heated up to Tcl From there, the heated recirculated brine is passed through the brine heater, where it is heated to its Top Brine Temperature (TBT). Brine at TBT exiting the brine heater, enters the flash chamber of the first stage heat recovery section, atbrinetemperature of Tbl =
TBT. Then, the brine cascades downward through the several stages oftheunit, flashing off some product vapor in each stage and leaving the last stage atbrinetemperature Tb7 . Part of the last stage brine is blown-down, mbd, and the rest is mixed with the make-up where the cycle is repeated.
b- Invented SYs~em Modifications There are three major modifications in the invented system which are superimposed on the MSF base system configuration described above. These modifications are illustrated in Figures 2 to 5 and are sumrnarized as follows (more detailed description of Figures 2 to 5 are given lafer in the drawing section):-1- Improve the Flash Chamber Effectiveness Flashing brine, coming out of the flash chamber of the existing MSF systems, always retains some residual non-equilibrium superheat that considerably aggravates the technical and economical characteristics of the MSF system. Approaching thermodynamic equilibrium is achieved, in the present invented system, through enhancing flashing rate within the flash chamber by:
i) increasing the brine flashing surface area and brineturbulence (improvebrine temperature gradient); for example two flashing trays with dripping (falling or sprayed) brine, from the upper to the lower tray(s), as shown in Figures 2 & 3.
ii) increasing brine superheat and the numberofactivenucleationsitesforvapor bubbles formation and vapor generation, using additional (external) heat, through a heating surface, placed between fl~hing trays, as will be presented below (brine reheat).
The number of brine flashing trays may increase more than two, for more evaporation surface in future larger capacity units. In this case, the additional heating surface may also be divided between these trays.
Patent ( 8128/96 ) 4 Dr. Hassan E. S. Fath - ~ 1 902~
DISTILLATION SYSTEM WITH BRINE REHEAT
SPECIFICATIONS
Field Of The Invention This invention relates generally to saline water des~lin~tion systems and more particularly to Multi Stage Flash (MSF) and Multi Effect (ME) ~listill~tion systems.
Description Of The Previous Systems Des~lin~tion of saline water by ~istill~tion is a very effective process, because most of the chemical materials found in saline water are non-volatile at the temperaturenormally employed and hence remain in the un-evaporated brine. The two most proven distillation technologies are: the Multi Stage Flash (MSF) and Multi Effect(ME) systems. The differences between the two types of technologies are derived from the difference in the method of heat transfer. The saline water is sensibly heated in the tubes in MSF system and boiled in a thin film on the tubes in ME system. Comparisons between MSF and ME systems indicated, in general, the superiority of each systemover the other in one aspect or the other.
MSF system has proven to be the most simple, and reliable technology for producing potable water on large scale. Due to its advantages and the acc-lmul~ted operational experience gained, MSF of the recirculated flow dominates the market. MSF has the advantage that the incoming brine is heated without evaporation and fl~hing evaporation occurs without heat transfer, thus reducing the tendency for scale to form on the heat transfer surface. The significant drawback of the MSF system, as compared to other cost effective systems, are the high energy consumption (steam, pumping and other operating costs). The system production and performance can be increased (and production cost can, therefore, be reduced) by increasing the Top Brine Temperature (TBT). The TBT is limited, however, due to the high temperature hard scale deposits in the brine heater and the up-to-date antiscalent limitations.
On the other hand, ME systems are widely used in the chemical industry forthe concentration of solutions. In seawater des~lin~tion, ME has not achieved similar importance, in terms of the total installed capacities, as MSF. The ME distillation system is significantly more efficient and has a thermodynamic superiority over MSF.
The striking feature of ME system is the significant low specific power consumption as compared to MSF system.
Patent ( 8128196 ) 2 Dr. Hassan E. S. Fath ~1 qO2~q The Invention Idea The objective of the invented system (named hereas: CombinedMSF-MESystem W th Brine Rehea~) is to increase saline water distillation unit capacity, improve its performance and, therefore, reduce the fresh water production cost over the existing MSF systems. The invented combined MSF-ME system wifh brine reheat introduces the concept of increasing the MSF fl~hing range through brine reheat, and utilizes the superior advantages of both MSF and ME systems simultaneously.
The invented system uses a combination of: i) the up-to-date (proven design) MSFevaporation system as a base system with dirrele.lt methods to improvetheflash chamber effectiveness (non-equilibrium factor) and fl~hin~ evaporation rate; ii)increases the fl~hing range through brine reheat, i.e. supply (all or part ofl the brine with additional (external) heat in brine reheaters (located after the brine heater and/or within the flash chambers), and; iii) superimposes the ME evaporation concept and system on the MSF base system. Themodificationsoftheinventedsystemoverthe existing MSF system are:
a- Since additional (external) heat, for higher fl~.~hingrange and morewater production, can't be supplied before or at the brine heater in existing MSF
system (due to TBT limitations), increasing the fl~hin~ range is carried out, in the present invented system, through brine reheat; i.e. the additional (external) heat is supplied to (all or part ofl the brine after the brine heaterand/or within flash chambers.
b- In addition to increasing brine superheat from (a), other methods are considered for improving MSF flash chamber effectiveness (the non-equilibrium factor) and fl~shing evaporation rate, for additional vapor production and better system performance. This includes; increasing fl~hin~
surface area, improving brine turbulence ( brine temperature gradient), and introducing more active nucleation sites for bubbles formation.
c- The vapor generated due to: i) brine reheat (from a) ii) the improvement in flash chamber effectiveness (from b), and iii) possibly part of the main vapor generated inside the flash chambers, is then used as a source of heat to generate more vapor in the next successive stages (effects) in a way similar to the conventional ME system; i.e.theinventedsystemsuperimposestheME
evaporation concept and system on the existing MSF system designs.
The invented system increases saline water distillation unit capacity, improves its performance and reduces the fresh water production cost. In addition, the invented system operates within the existing (proven design) MSF and ME system's constraints and limitations, and allows for the possibility of utilizing waste heat as the external heat source for brine reheat. The invented system presents, therefore, a break-through for the future generation of saline water desalination systems.
Patent ( 8128196 ) 3 Dr Hassan E. S. Fath - 2l9029q.
Description Of The Invention a- MSF Base System Conf guration Figure 1 shows (for demonstration) a small unit of a typical Multi Stage Flash (MSF) distillation system of the recirculation type. The unit consists of four stages of heat recovery section and two stages of heat rejection section as shown. Seawater enters the condense tubes of the heat rejection section at the lowest temperature, Tl", and is heated up to temperature Tc5~ by condensation of the vapor generated bybrine fl~ching in the heat rejection section. At this point, much ofthe cooling seawater, mrej, is discharged from the plant for heat rejection and thebalance make-up, mr~ p, is rnixed with part of the brine flowing out of the last stage of the heat rejection section.
This mixture (at Trcc) forms the recirculated brine, mrec, and ispumped throughthe condenser tubes of the heat recovery section where it is heated up to Tcl From there, the heated recirculated brine is passed through the brine heater, where it is heated to its Top Brine Temperature (TBT). Brine at TBT exiting the brine heater, enters the flash chamber of the first stage heat recovery section, atbrinetemperature of Tbl =
TBT. Then, the brine cascades downward through the several stages oftheunit, flashing off some product vapor in each stage and leaving the last stage atbrinetemperature Tb7 . Part of the last stage brine is blown-down, mbd, and the rest is mixed with the make-up where the cycle is repeated.
b- Invented SYs~em Modifications There are three major modifications in the invented system which are superimposed on the MSF base system configuration described above. These modifications are illustrated in Figures 2 to 5 and are sumrnarized as follows (more detailed description of Figures 2 to 5 are given lafer in the drawing section):-1- Improve the Flash Chamber Effectiveness Flashing brine, coming out of the flash chamber of the existing MSF systems, always retains some residual non-equilibrium superheat that considerably aggravates the technical and economical characteristics of the MSF system. Approaching thermodynamic equilibrium is achieved, in the present invented system, through enhancing flashing rate within the flash chamber by:
i) increasing the brine flashing surface area and brineturbulence (improvebrine temperature gradient); for example two flashing trays with dripping (falling or sprayed) brine, from the upper to the lower tray(s), as shown in Figures 2 & 3.
ii) increasing brine superheat and the numberofactivenucleationsitesforvapor bubbles formation and vapor generation, using additional (external) heat, through a heating surface, placed between fl~hing trays, as will be presented below (brine reheat).
The number of brine flashing trays may increase more than two, for more evaporation surface in future larger capacity units. In this case, the additional heating surface may also be divided between these trays.
Patent ( 8128/96 ) 4 Dr. Hassan E. S. Fath - ~ 1 902~
2- Brine Reheat - For higher production rate of MSF system, additional vapor generation canbe attained by increasing brine flashing range. Additional (external) heat can not be supplied to the brine before or at the brine heater (due to TBT limitations). In the present invented system, additional (external) heat is supplied to the brine, after the brine heater (known here as brine reheaf) The additional (external) heat (for brine reheat) could be supplied to (all or part of) the brine: i) within the flash chamber(s) (named here as: internal brine reheaters), ii) through outside heat exchanger(s) (named here as: ex~ernal brine rehea~ers); or iii) combination of both (i) and (ii).
Adding heat to the brine, within the flash chamber, will be supplied through a tube bank under the dripping (falling or sprayed) brinefromtheuppertray, Figure 3.
Sup.plying the system with additional heat through tube bank has the following advantages:
(i) generating more vapor due to the additional heat (higher fl~ching range), (ii) enhancing brine fl~hing rate due to higher brine superheat, (iii) improving the brine turbulence and the temperature gradient, due to the brine falling over heating surface tube bank, (iv) creation of additional active nucleation sites for more bubbling and more vapor production (better flash chamber effectiveness) Based on the optimum arrangement (design, operational, scale and corrosion control, cost,...etc.), the brine reheat could be attained at single brine reheater (top drawing of Figure 4) or being divided between two brine reheaters (middle and bottom drawings of Figure 4), or through more than two reheaters.
Adding heat to the brine, within the flash chamber, will be supplied through a tube bank under the dripping (falling or sprayed) brinefromtheuppertray, Figure 3.
Sup.plying the system with additional heat through tube bank has the following advantages:
(i) generating more vapor due to the additional heat (higher fl~ching range), (ii) enhancing brine fl~hing rate due to higher brine superheat, (iii) improving the brine turbulence and the temperature gradient, due to the brine falling over heating surface tube bank, (iv) creation of additional active nucleation sites for more bubbling and more vapor production (better flash chamber effectiveness) Based on the optimum arrangement (design, operational, scale and corrosion control, cost,...etc.), the brine reheat could be attained at single brine reheater (top drawing of Figure 4) or being divided between two brine reheaters (middle and bottom drawings of Figure 4), or through more than two reheaters.
3- SuperimposingME System In the present invented system, each stage supplied with external (additional) heat (brine reheat, through internal or external brine reheaters) is considered as the first effect of ME system superimposed on the MSF base system. The vapor generated due to: i) improving flash chamber effectiveness, from 1 above, ii) the additional external heat (from 2 above), and iii) possibly partofthemainvaporgenerated inside the earlier flash chamber(s), is used as the source of heat to generate more vapor in the next successive stages (effects) as in ME concept, i.e. ME system is superimposed on MSF base system, as shown in Figures 2 to 4.
The additional vapor generated in each effect is condensed insidethe additional heating surface(s) of the following effect(s) as additional distillate, Figure 2 & 3.
The latent heat of condensation is used as a source of heat for that (next) effect, similar to the conventional ME system.
The main (and the additional) distillate formed in each stage (effect) is discharged through orifices to the next stage (effect) where it forms more vapor by fl~shing and Patent ( 8128196 ) 5 Dr. Hassan E. S. Fath augments the heating in that stage (effect), in a similar way to the conventional MSF
(ME) systems.
The heat transfer surface (tube bank) in each effect is a placed under the dripping (falling or sprayed) brine from an upper tray(s), Figure 3. This arrangement has the following additional features:
(i) there will be a partial brine flashing from the upper tray(s) and fromthe dripping (falling or sprayed) brine before cont~cting the heating surface. This causes larger temperature difference between the heating surface and the boiling brine (in addition to the higherheattransfercoefficientofthefalling brine) which enhances boiling heat transfer and reduces the required heating surface area.
(ii) dripping (falling or sprayed) falling brine, decreases the residence time required . for scale formation on the additional heating surface, as in conventional ME
system.
The additional heating surface(s) inside the flash chamber of each effect may, however, be elimin~ted. Direct contact heating of the brine could beused instead of surface heating. The heating vapor will, therefore, be injected from the previous effect into the flash chamber and under the falling brine. In such case:
(a) The injected heating vapor will be de-pressurized and superheated through the throttling process from the previous effect pressure.
(b) Mass & heat will directly be exchanged between the superheated heating vaporand the saturated (or superheated) fallingbrine. Theheatingvapor superheat energy will be used to generate the additional vapor in this effect.
(c) The heating vapor will be condensed on the flash chamber condensertubes, while the additional vapor will be injected into the next effect where the process is repeated.
(d) Flimin~tion of the heating surface will reduce the total plant costs and will eliminate the problems of heating surface(s) corrosion and scale deposits.
(e) The present (or modified) methods and techniques for enhancing the heat and mass transfer between the heating vapor and falling brine may be used. Part of the heating vapor may also be injected into the brine layer(s) in orderto improve the evaporation rates (due to increase the brine superheat, turbulence and the number of active nucleation sites for bubbles formation).
With large number of stages, more ME effects could be superimposed on the MSF
base system to improve the system performance and increase theproduction. The invented system may then be divided into two or more segments of ME systems.
In the invented system, each stage supplied with external heat (brine reheat through either internal or external brine reheaters) is considered the first effect of ME system superimposed on the MSF base system. The first effect of each ME segment need not to be the first stage of the MSF segment. It may be the first, second, or other stages based on the optimum design and operational arrangement. The second effect need not Patent ( 8128/96 ) 6 Dr. Hassan E. S. Fath to be the following stage, but it may be one of other following stages, depending on the temperature difference required for optimum heating surface area. Similarly for the third and following ME effects. Typical examples of the invented system combinations are illustrated in Figure 4.
Additional Considerations for The Invention Due to the increase in the reheated brinetemperature,thevacuumofthefollowing stages can partially be relaxed and redistributed along the rest of reheated stages. The saturation temperature can, therefore, be increased to enhance the heat transfer across the condenser heat transfer surface. Higher heat transfer rate across leads to areduction in the heat transfer surface required and/or increase in the recirculating brine temperature that reduces the brine heater heating steam requirements. These factors have the economical value of reducing both capital (heating surface) and operating (heating steam) costs.
The additional heat could be live heating steam (extracted from the turbine, part of the steam exits from a back pressure turbine, or from auxiliary steam source) or other hot fluid. Alternatively, a waste heat recovery system could be installed to utilize the plant waste heat (For example: boiler blow-down, flue gas energy,...etc.) instead of all (or part of) the additional heat source.
Since fl~chin.~ brine is at or above saturation temperature, the supplied additional (external) heat as well as heat generated in each effect are fully used for the evaporation of the additional vapor production (in the following effects). No heat is required to preheat the brine (from the cold seawater temperature to theboiling temperature).
With minim~lm pressure drop of the fl~hing brine flow, the brine may have sufficient interstage pressure di~rel enlial to raise the brine from the lower tray of one stage to the upper tray of the next stage. In case the pressure dirrel elllial is not sufficient, either i) a reduction in the total number of flash stages may be necessary, or ii) the required pressure di~e. enlial could be attained through an additional head per stage; potential head (stepped down stages) and/or pressure head (circ~ ting pumps), as described in the drawing section and shown in Figures 5 (a, b and c).
Brine temperatures, inside the condenser tubes of the MSF base system, is m~int~ined within optimum design range by the adjustments of the recirculation, reject blow-down and make-up flow rates. In case of increasing the recirculated brine flow, part of the additional generated vapor could be condensed on the condenser tubes of each stage to m~int~in the system parameters near optimum values. In this case, the required additional heating surface area (for brine reheat) is reduced. Similarly, TopBrine Temperature (TBT) is also m~int~ined withinthe specified (up-to-date) upperlimit(for maximum fl~ching range and brine heater hard scale control).
Part of the main vapor generated inside the flash chambers may be used as a source of heat (for brine reheat). In this case, the heat transfer surface area required for the main Patent ( 8128196 ) 7 Dr. Haccan E. S. Fath 21 ~029~
condensers as well as the brine recirculation rate (and, therefore, recirculation pump size and power) will be reduced, and the brine temperature difference across the brine heater will be increased (for better heat transfer). Optimum design parameters should be obtained.
A small part of the vapor generated inside the flash chambers in earlier stages (effects), could also be used for bubbling & heating the brine in later stages (in direct contact).
This higher pressure vapor will first be throttled to the lowerpressure stages. The bubbling superheated vapor will increase the brine superheat (in the later stages) and will act as an additional source for active nucleation sites to enhance brine bubbling and fl~ching rate; i.e. improve the flash chamber effectiveness (non-equilibrium factor) and production rate. Optimum design parameters ( such as vapor rate, stages number and bubbling arrangement,... etc.) should be obtained.
Optimum design parameters, (such as number of stages, number of segments, numberof effects, brine reheaters's size, type and number, stage size, heattransfer surface area(s), the recirculation, reject blow-down and make-up flow rates... etc.) will be selected, based on full or partial utilization of the given invented system combinations.
The other design limitations should also be preserved when considering the flashchamber re-sizing, for example: i) brine velocity insidethe condensertube, ii) tube length and tube diameter, iii) stage maximum specific brine flow, and, iv) stagemaximum vapor release velocity.
With the supply of a percentage of the brine heater heat load (for brine reheat), the invented system increases the specific unit capacity and production rate, and improves the unit performance (i.e. Gained Output Ratio-GOR), and reduces, therefore, thefresh water production cost, as compared to the present MSF system. GOR is further increased and production cost is further reduced when waste heat is used as (part or all of) the additional (external) heat source for brine reheat.
The additional heat transfer surface temperature will be m~int~ined less than the brine heater tubes surface temperature. On the other hand, brine concentration in the flash chambers is controlled within acceptable range by the adjustments of the recirculation, reject blow-down and make-up flow rates. Since brine contains enough antiscalent (for brine heater hard scale control), and is partially flashed and cooled down in the flash chambers of earlier stages, and with its small residence time on the additional heating surfaces (brine reheater and ME boiling surfaces), problems of high temperature hard scale deposits on these additional heating surfaces will be under control.
The additional vapor generated in the last stage is condensed on the condenser tubes of the heat rejection section as conventional MSF and ME systems. Another alternative to be considered, is to compress the vapor generated in the last stage through a vapor compression system (VC) and utilize the compressed hot vapor as the source of heat for brine reheat (instead of additional live steam). Optimum MSF + ME + VC system combination should be obtained.
Patent ( 8128196 ) 8 Dr. H~ss~n E. S. F;lth DRAWINGS
Brief Descripfion of the Drawings T,??e schema~ic process diagrams shown in Figures I ~o 5 and brief ly described below, do not show all the auxiliary sys~ems and componen~s required to opera~e ~he plan~, and should be regarded as limi~ed ~o ~heir s~a~ed purpose of illustra~ing ~he invented sysfem (combined MSF-ME system wi~h brine rehea~) process concept Figure I
Figure 1 shows (for demonstration) a small unit of a typical Multi Stage Flash (MSF) distillation system of the recirculation type. The unit consists of four stages of heat recovery section and two stages of heat rejection section as shown. Seawater enters the condenser tubes of the heat rejection section at the lowest temperature, T", and is heated up to temperature TC5a by condensation of the vapor generated, by brine fl~ching, in the heat rejection section. At this point, much ofthe cooling seawater, mrej, is discharged from the plant for heat rejection and thebalance make-up, m~r,",,p, is mixed with part of the brine flowing out of the last stage of the heat rejection section.
The mixture, at TreC~ forms the recirculated brine, mr~c, and is pumped through the condenser tubes of the heat recovery section where it is heated up to TCI- From there, the heated recirculated brine is passed through the brine heater, where it is heated to its Top Brine Temperature (TBT). Brine at TBT exiting the brine heater, enters the flash chamber of the first stage of the heat recovery section, at brine temperature of Tbl = TBT. Then, the brine cascades downward throughtheseveralstagesoftheunit, fl~ching off some product vapor in each stage and leaving the last stageatbrine temperature Tb7 . Part of the last stage brine is blown-down, mbd, and the rest is mixed with the make-up where the cycle is repeated.
Figure 2 Introduction Figure 2 shows the conceptual process diagram of the invented combined MSF-ME
system with brine reheat. Figure 2 is the process design configuration MSF small unit presented in Figure 1 with following modifications: i) improved flash chamber internals for higher effectiveness, ii) brine reheat for higher fl~chinp range (the addition of external heat supplied to the brine), and iii) superimposing the ME system on the MSF system. More details of these modifications are:
Descrip~ion i) Each flash chamber contains two (or more) trays with dripping (falling or sprayed) brine from the upper tray to the lower tray(s). The brine enters the flash chamber into the upper tray, partially flash and then falls down, throughthe additional heating surface (if any), with more flashing, to the lower tray(s) for more fl~ching and, then, exits to the next stage. Higher flash chamber effectiveness (better non-equilibrium factor) is, therefore, attained due to higher fl~ching surface area, brine turbulence, additional brine superheat and extra active nucleation sites. The heat Patent ( 8128/96 ) ~ / Dr. Hassan E. S. Fath 21 9()299 transfer surface is a tube bank under the dripping (or sprayed) brine fromthe upper to the lower tray.
ii) Additional external heat (heating steam or waste heat) is supplied to the brine (for brine reheat) in the flash chamber of the third stage of the MSF system (one internal brine reheater). Flashing range is increased and additional vapor is generated, and the plant production is, therefore, increased.
iii) The third MSF stage with brine reheat is considered as the first effect in the ME
system superimposed on the MSF system. External heating is supplied to this (first ME effect) stage and may also be supplemented by some vaporgenerated in earlier (first & second) stages. Additional vapor is generated in this third MSFstage (first ME effect) due to improving the flash chamber effectiveness from (i) and due to the brine reheat from (ii). The additional vapor generated will pass to the fourth MSF stage as the additional heating source. The fourth stage is considered the second effect of the ME system superimposed on the MSF system.
This vapor is condensed as additional ~i~till~te and the latent heat of condensation is used to generate more vapor in the next effect (fifth MSF stage). The fifth stage is considered as the third effect of the ME system, where the process is repeated.
Addifional Considerations A small part of the vapor generated inside the flash chambers in earlier stages (effects), could also be used for bubbling & heating the brine in later stages (in direct contact).
This higher pressure vapor will first be throttled to the lowerpressure stages. The bubbling superheated vapor will increase the brine superheat (in the later stages) and will act as an additional source for active nucleation sites to enhance brine bubbling and flashing rate, i.e. improve the flash chamber effectiveness (non-equilibrium factor) and production rate. Optimum design parameters, (such as vapor rate, stages number and bubbling arrangement,... etc.) should be obtained.
The main and additional distill~te formed in each stage (effect) is discharged through orifices to the next stage (effect) where it forms vapor by fl~hing and augments the heating in that stage (effect), in a similar way to the conventional MSF (ME) systems.
The vapor generated in the last (sixth) stage will be condensed through the heatrejection section as conventional MSF and ME systems. Anotheralternative, isto compress this vapor through a vapor compression system (VC) and utilize the compressed hot steam as the source of heat for brine reheat, instead of (all or part of) the additional (external) heating steam.
The rest of the MSF-ME system flow diagram is similar to that described in Figure 1 above and the conventional MSF and ME systems.
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Patent ( 8128196 ) ~ Dr. Hassarl E. S. Fath Figure 3 Introduction Figure 3 shows an enlargement of one intermediate combined MSF-ME flash chamber of the invented system configuration presented in Figure 2. The flash chamber contains two (or more) trays with dripping (or sprayed) brine from the upper tray to the lower tray. External heat or internally generated heating vapor is supplied to the brine through a tube bank under the dripping (sprayed) brine from the upper tray (falling film). The vapor generated due to this additional heating source and due to improving fl~ching chamber effectiveness is used as the heating source (to generate more additional vapor) in the next and successive stages (effects).
Description Similar to the existing (up-to-date) MSF provendesign,thetopsectionoftheflash chamber contains the condenser tubes where the recirculated brine of flow rate mc~;) enters .at temperature TC(i+l) and exits at temperature Tc,;). The flashed vapor condenses as the main distillate and exits the flash chamber at flow rate mp; and temperature Ts;
The bottom section of the flash chamber contains the two trays of dripping brine and the additional heating surface. Superheated brine enters the uppertrayoftheflashchamber at flow rate of mbi and temperature Tb;. The brine is partially flashed in the upper tray while the rest of the brine falls down to the lowertray(s) through the additional heating surface. The falling brine will further be flashed/boiled (due to the extra superheat, large fl~hing surface area, turbulence and the active nucleation sites) and generate additional vapor. More flashing takes place at the lower tray after which the brine exits to the next stage (effect) at flow rate mb(j+l) and temperature Tb(j+l). The vapor rises (through the conventional demisters), partially to the condenser tubes and partially as a heating vapor to the next effect.
Heating vapor from the previous effect [stage (i-l)] enters the additionalheating surface, condense as additional distillate, and its latent heat of condensation is used as the heating source to heat and boil the falling brine. The additional vapor generated (due to the additional heat and due to improving fl~hing chamber effectiveness) will exit the flash chamber as the heating vapor to the next effect [stage (i+1)], similar to ME system.
Figure 4 Introduction The additional external heat (for brine reheat) could be supplied: (i) within the flash chamber (named here: internal brine reheater), (ii) through an outside heat exchanger (named here, external brine reheater); or (iii) combination of both (i) and (ii). In addition, for MSF units of large number of stages, more ME effects are utilized to increase the unit production and performance. ThecombinedMSF-MEsystemwith brine reheat may, therefore, be divided into two or more segments and each MSF-ME
segment starts with brine reheater. Each stage supplied with external heat (for brine reheat) is considered as the first ME effect superimposed on MSF base system.
Patent ( 8/28/96 ) ,~ // Dr. Hassan E. S. Fath The first effect of ME system need not to be the first stage of the MSF system. It may be the first, second, or other stages based on the optimum design arrangement ( cost, operational, scale and corrosion control,...etc.). The second effect of each ME segment need not be the next stage, but may be one of the other following stages, depending on the temperature difference required for the heating surface. Similarly for the third and following effects.
Descripfion Figure 4 shows three arrangements (as examples) of the invented combined MSF-ME
sys~em with brine rehea~ of a larger number of stages. 12 MSF stages are shown for demonstration, where the stage number is shown on the top of the Figure. The same conceptual arrangement is applied to other larger units.
In the top drawing arrangement . the external additional heat (forbrine reheat) is supplied to a single MSF stage (MSF stage number 3) and considered as the first effect of the ME system. This additional heat is supplied to the brine through one internal brine reheater. The ME second effect is superimposed on MSF-stage 5, the third effect is on MSF-stage 7 and the fourth and fifth effects on MSF stages 9 and 11 respectively. The first effect (MSF stage 3) is suppliedwithexternal heatwhilethe subsequent effects (from 2 to 5) obtain their heat source from the vapor generated in the previous effect, i.e. this drawing illustrates 1*5 effects of ME system, with single internal brine reheater, superimposed on the 12 stages of MSF system.
In the middle drawing arrangement, the invented system is divided into two segments.
Each segment consists of 6 MSF stages, 5 ME effects and one internal brine reheater.
In the first segment, the external additional heat (for brine reheat) is supplied at the second MSF stage (and considered as the first effect of the first ME segment). For the second ME segment, the external additional heat (for brine reheat) is supplied at the eighth MSF stage (the first effect of the second ME segment). The first ME effect in each segment is supplied with external heat through intemal brine reheater, and the subsequent effects in each segment (from 2 to 5) obtaintheirheat source fromthe vapor generated in the previous effect, i.e. this drawing illustrates 2 * 5 effects of ME
system, with two internal brine reheaters, superimposed on the 12stagesofMSF
system.
In the bottom drawin~ arrangement. the invented system is also divided into two di~lelll segments. The firsf segment consists of 7 MSF stages, one internal brine reheater and 4 ME effects. In this segment, the first three stages are pure MSF with enhanced fl~shing The external additional heat (forbrinereheat)issuppliedatthe fourth MSF stage (first ME effect of the this segment). The subsequent effects (the second, third, and fourth effects) obtain their additional heat from the vapor generated in the previous effect. The second segment consists of the following 5 MSF stages, one external brine reheater and 5 ME effects. The external additional heat (for brine reheat) is supplied at the eighth MSF stage (first ME effect of the second segment).
The subsequent effects (from second to fifth effects) obtain their additional heat from the vapor generated in the previous effect, i.e. this drawing illustrates 1 * 4 + 1*5 effects of ME system, one internal + one external brine reheaters, superimposed on the 12 stages of MSF system.
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Patent ( 8128196 ) ~, Dr. Hassan E. S. Fath 2 1 qO299 For larger number of stages of MSF units similar MSF-ME-brine reheaterscombination with dirrel e.-l break-downs could be applied.
r~gure S
In~roduction With minim~lm pressure drop of the flashing brine, the brine may havesufficient interstage pressure di~erential to raise the brine from the lower tray of one stage to the upper tray of the next stage. In case thepressuredirrelenlialisnotsufficient: (i)a reduction in the total number of MSF stages will be necessary, or (ii) the required pressure dirrere,.~ial could be attained through an additional external potential or/and pressure head per stage.
Descripfion Figure 5 presents three basic concepts to obtain higher inter-stage pressure di~eren~ials. The invented system consists of 2*4 effects of ME system, twobrinereheaters superimposed on 12 stages of MSF system. Similar conceptual arrangement will be applied to other larger or di~erent arrangement units.
Fi~ure Sa is a full stepped-down configuration. Additional interstage pressure dirreren~ial is obtained from the hydro-static (potential) head difference. Thisarrangement may need, however, a stronger supporting structure (due to thehigh elevation) in the first stages.
Figure 5b is a combination of stepped-down configuration and the utilization of circ.ll~ting pumps. In each segment (or group of stages) the additional interstage pressure dirrere"lial is obtained from the hydro-static (potential) head difference. The circul~ting pumps provide the pressure head required between each two segments and to overcome the brine reheater pressure drop. This arrangement reduces the need for stronger supporting structure. However, this should be balanced with the capital and running costs of the pumps.
Figure Sc is similar to the arrangement in Figure 5b except that the arrangement of stages in each segment is made vertical rather than the stepped-down configuration of Figure 5b. In each segment (or group of stages) the additional interstage pressure differential is obtained from the hydro-static (potential) head difference. The circlllating pumps provide the pressure head required between each two segments and to overcome the brine reheater pressure drop.
Patent ( 8128196 ) ~G /3 Dr. Hassan E. S. Fath
The additional vapor generated in each effect is condensed insidethe additional heating surface(s) of the following effect(s) as additional distillate, Figure 2 & 3.
The latent heat of condensation is used as a source of heat for that (next) effect, similar to the conventional ME system.
The main (and the additional) distillate formed in each stage (effect) is discharged through orifices to the next stage (effect) where it forms more vapor by fl~shing and Patent ( 8128196 ) 5 Dr. Hassan E. S. Fath augments the heating in that stage (effect), in a similar way to the conventional MSF
(ME) systems.
The heat transfer surface (tube bank) in each effect is a placed under the dripping (falling or sprayed) brine from an upper tray(s), Figure 3. This arrangement has the following additional features:
(i) there will be a partial brine flashing from the upper tray(s) and fromthe dripping (falling or sprayed) brine before cont~cting the heating surface. This causes larger temperature difference between the heating surface and the boiling brine (in addition to the higherheattransfercoefficientofthefalling brine) which enhances boiling heat transfer and reduces the required heating surface area.
(ii) dripping (falling or sprayed) falling brine, decreases the residence time required . for scale formation on the additional heating surface, as in conventional ME
system.
The additional heating surface(s) inside the flash chamber of each effect may, however, be elimin~ted. Direct contact heating of the brine could beused instead of surface heating. The heating vapor will, therefore, be injected from the previous effect into the flash chamber and under the falling brine. In such case:
(a) The injected heating vapor will be de-pressurized and superheated through the throttling process from the previous effect pressure.
(b) Mass & heat will directly be exchanged between the superheated heating vaporand the saturated (or superheated) fallingbrine. Theheatingvapor superheat energy will be used to generate the additional vapor in this effect.
(c) The heating vapor will be condensed on the flash chamber condensertubes, while the additional vapor will be injected into the next effect where the process is repeated.
(d) Flimin~tion of the heating surface will reduce the total plant costs and will eliminate the problems of heating surface(s) corrosion and scale deposits.
(e) The present (or modified) methods and techniques for enhancing the heat and mass transfer between the heating vapor and falling brine may be used. Part of the heating vapor may also be injected into the brine layer(s) in orderto improve the evaporation rates (due to increase the brine superheat, turbulence and the number of active nucleation sites for bubbles formation).
With large number of stages, more ME effects could be superimposed on the MSF
base system to improve the system performance and increase theproduction. The invented system may then be divided into two or more segments of ME systems.
In the invented system, each stage supplied with external heat (brine reheat through either internal or external brine reheaters) is considered the first effect of ME system superimposed on the MSF base system. The first effect of each ME segment need not to be the first stage of the MSF segment. It may be the first, second, or other stages based on the optimum design and operational arrangement. The second effect need not Patent ( 8128/96 ) 6 Dr. Hassan E. S. Fath to be the following stage, but it may be one of other following stages, depending on the temperature difference required for optimum heating surface area. Similarly for the third and following ME effects. Typical examples of the invented system combinations are illustrated in Figure 4.
Additional Considerations for The Invention Due to the increase in the reheated brinetemperature,thevacuumofthefollowing stages can partially be relaxed and redistributed along the rest of reheated stages. The saturation temperature can, therefore, be increased to enhance the heat transfer across the condenser heat transfer surface. Higher heat transfer rate across leads to areduction in the heat transfer surface required and/or increase in the recirculating brine temperature that reduces the brine heater heating steam requirements. These factors have the economical value of reducing both capital (heating surface) and operating (heating steam) costs.
The additional heat could be live heating steam (extracted from the turbine, part of the steam exits from a back pressure turbine, or from auxiliary steam source) or other hot fluid. Alternatively, a waste heat recovery system could be installed to utilize the plant waste heat (For example: boiler blow-down, flue gas energy,...etc.) instead of all (or part of) the additional heat source.
Since fl~chin.~ brine is at or above saturation temperature, the supplied additional (external) heat as well as heat generated in each effect are fully used for the evaporation of the additional vapor production (in the following effects). No heat is required to preheat the brine (from the cold seawater temperature to theboiling temperature).
With minim~lm pressure drop of the fl~hing brine flow, the brine may have sufficient interstage pressure di~rel enlial to raise the brine from the lower tray of one stage to the upper tray of the next stage. In case the pressure dirrel elllial is not sufficient, either i) a reduction in the total number of flash stages may be necessary, or ii) the required pressure di~e. enlial could be attained through an additional head per stage; potential head (stepped down stages) and/or pressure head (circ~ ting pumps), as described in the drawing section and shown in Figures 5 (a, b and c).
Brine temperatures, inside the condenser tubes of the MSF base system, is m~int~ined within optimum design range by the adjustments of the recirculation, reject blow-down and make-up flow rates. In case of increasing the recirculated brine flow, part of the additional generated vapor could be condensed on the condenser tubes of each stage to m~int~in the system parameters near optimum values. In this case, the required additional heating surface area (for brine reheat) is reduced. Similarly, TopBrine Temperature (TBT) is also m~int~ined withinthe specified (up-to-date) upperlimit(for maximum fl~ching range and brine heater hard scale control).
Part of the main vapor generated inside the flash chambers may be used as a source of heat (for brine reheat). In this case, the heat transfer surface area required for the main Patent ( 8128196 ) 7 Dr. Haccan E. S. Fath 21 ~029~
condensers as well as the brine recirculation rate (and, therefore, recirculation pump size and power) will be reduced, and the brine temperature difference across the brine heater will be increased (for better heat transfer). Optimum design parameters should be obtained.
A small part of the vapor generated inside the flash chambers in earlier stages (effects), could also be used for bubbling & heating the brine in later stages (in direct contact).
This higher pressure vapor will first be throttled to the lowerpressure stages. The bubbling superheated vapor will increase the brine superheat (in the later stages) and will act as an additional source for active nucleation sites to enhance brine bubbling and fl~ching rate; i.e. improve the flash chamber effectiveness (non-equilibrium factor) and production rate. Optimum design parameters ( such as vapor rate, stages number and bubbling arrangement,... etc.) should be obtained.
Optimum design parameters, (such as number of stages, number of segments, numberof effects, brine reheaters's size, type and number, stage size, heattransfer surface area(s), the recirculation, reject blow-down and make-up flow rates... etc.) will be selected, based on full or partial utilization of the given invented system combinations.
The other design limitations should also be preserved when considering the flashchamber re-sizing, for example: i) brine velocity insidethe condensertube, ii) tube length and tube diameter, iii) stage maximum specific brine flow, and, iv) stagemaximum vapor release velocity.
With the supply of a percentage of the brine heater heat load (for brine reheat), the invented system increases the specific unit capacity and production rate, and improves the unit performance (i.e. Gained Output Ratio-GOR), and reduces, therefore, thefresh water production cost, as compared to the present MSF system. GOR is further increased and production cost is further reduced when waste heat is used as (part or all of) the additional (external) heat source for brine reheat.
The additional heat transfer surface temperature will be m~int~ined less than the brine heater tubes surface temperature. On the other hand, brine concentration in the flash chambers is controlled within acceptable range by the adjustments of the recirculation, reject blow-down and make-up flow rates. Since brine contains enough antiscalent (for brine heater hard scale control), and is partially flashed and cooled down in the flash chambers of earlier stages, and with its small residence time on the additional heating surfaces (brine reheater and ME boiling surfaces), problems of high temperature hard scale deposits on these additional heating surfaces will be under control.
The additional vapor generated in the last stage is condensed on the condenser tubes of the heat rejection section as conventional MSF and ME systems. Another alternative to be considered, is to compress the vapor generated in the last stage through a vapor compression system (VC) and utilize the compressed hot vapor as the source of heat for brine reheat (instead of additional live steam). Optimum MSF + ME + VC system combination should be obtained.
Patent ( 8128196 ) 8 Dr. H~ss~n E. S. F;lth DRAWINGS
Brief Descripfion of the Drawings T,??e schema~ic process diagrams shown in Figures I ~o 5 and brief ly described below, do not show all the auxiliary sys~ems and componen~s required to opera~e ~he plan~, and should be regarded as limi~ed ~o ~heir s~a~ed purpose of illustra~ing ~he invented sysfem (combined MSF-ME system wi~h brine rehea~) process concept Figure I
Figure 1 shows (for demonstration) a small unit of a typical Multi Stage Flash (MSF) distillation system of the recirculation type. The unit consists of four stages of heat recovery section and two stages of heat rejection section as shown. Seawater enters the condenser tubes of the heat rejection section at the lowest temperature, T", and is heated up to temperature TC5a by condensation of the vapor generated, by brine fl~ching, in the heat rejection section. At this point, much ofthe cooling seawater, mrej, is discharged from the plant for heat rejection and thebalance make-up, m~r,",,p, is mixed with part of the brine flowing out of the last stage of the heat rejection section.
The mixture, at TreC~ forms the recirculated brine, mr~c, and is pumped through the condenser tubes of the heat recovery section where it is heated up to TCI- From there, the heated recirculated brine is passed through the brine heater, where it is heated to its Top Brine Temperature (TBT). Brine at TBT exiting the brine heater, enters the flash chamber of the first stage of the heat recovery section, at brine temperature of Tbl = TBT. Then, the brine cascades downward throughtheseveralstagesoftheunit, fl~ching off some product vapor in each stage and leaving the last stageatbrine temperature Tb7 . Part of the last stage brine is blown-down, mbd, and the rest is mixed with the make-up where the cycle is repeated.
Figure 2 Introduction Figure 2 shows the conceptual process diagram of the invented combined MSF-ME
system with brine reheat. Figure 2 is the process design configuration MSF small unit presented in Figure 1 with following modifications: i) improved flash chamber internals for higher effectiveness, ii) brine reheat for higher fl~chinp range (the addition of external heat supplied to the brine), and iii) superimposing the ME system on the MSF system. More details of these modifications are:
Descrip~ion i) Each flash chamber contains two (or more) trays with dripping (falling or sprayed) brine from the upper tray to the lower tray(s). The brine enters the flash chamber into the upper tray, partially flash and then falls down, throughthe additional heating surface (if any), with more flashing, to the lower tray(s) for more fl~ching and, then, exits to the next stage. Higher flash chamber effectiveness (better non-equilibrium factor) is, therefore, attained due to higher fl~ching surface area, brine turbulence, additional brine superheat and extra active nucleation sites. The heat Patent ( 8128/96 ) ~ / Dr. Hassan E. S. Fath 21 9()299 transfer surface is a tube bank under the dripping (or sprayed) brine fromthe upper to the lower tray.
ii) Additional external heat (heating steam or waste heat) is supplied to the brine (for brine reheat) in the flash chamber of the third stage of the MSF system (one internal brine reheater). Flashing range is increased and additional vapor is generated, and the plant production is, therefore, increased.
iii) The third MSF stage with brine reheat is considered as the first effect in the ME
system superimposed on the MSF system. External heating is supplied to this (first ME effect) stage and may also be supplemented by some vaporgenerated in earlier (first & second) stages. Additional vapor is generated in this third MSFstage (first ME effect) due to improving the flash chamber effectiveness from (i) and due to the brine reheat from (ii). The additional vapor generated will pass to the fourth MSF stage as the additional heating source. The fourth stage is considered the second effect of the ME system superimposed on the MSF system.
This vapor is condensed as additional ~i~till~te and the latent heat of condensation is used to generate more vapor in the next effect (fifth MSF stage). The fifth stage is considered as the third effect of the ME system, where the process is repeated.
Addifional Considerations A small part of the vapor generated inside the flash chambers in earlier stages (effects), could also be used for bubbling & heating the brine in later stages (in direct contact).
This higher pressure vapor will first be throttled to the lowerpressure stages. The bubbling superheated vapor will increase the brine superheat (in the later stages) and will act as an additional source for active nucleation sites to enhance brine bubbling and flashing rate, i.e. improve the flash chamber effectiveness (non-equilibrium factor) and production rate. Optimum design parameters, (such as vapor rate, stages number and bubbling arrangement,... etc.) should be obtained.
The main and additional distill~te formed in each stage (effect) is discharged through orifices to the next stage (effect) where it forms vapor by fl~hing and augments the heating in that stage (effect), in a similar way to the conventional MSF (ME) systems.
The vapor generated in the last (sixth) stage will be condensed through the heatrejection section as conventional MSF and ME systems. Anotheralternative, isto compress this vapor through a vapor compression system (VC) and utilize the compressed hot steam as the source of heat for brine reheat, instead of (all or part of) the additional (external) heating steam.
The rest of the MSF-ME system flow diagram is similar to that described in Figure 1 above and the conventional MSF and ME systems.
/~
Patent ( 8128196 ) ~ Dr. Hassarl E. S. Fath Figure 3 Introduction Figure 3 shows an enlargement of one intermediate combined MSF-ME flash chamber of the invented system configuration presented in Figure 2. The flash chamber contains two (or more) trays with dripping (or sprayed) brine from the upper tray to the lower tray. External heat or internally generated heating vapor is supplied to the brine through a tube bank under the dripping (sprayed) brine from the upper tray (falling film). The vapor generated due to this additional heating source and due to improving fl~ching chamber effectiveness is used as the heating source (to generate more additional vapor) in the next and successive stages (effects).
Description Similar to the existing (up-to-date) MSF provendesign,thetopsectionoftheflash chamber contains the condenser tubes where the recirculated brine of flow rate mc~;) enters .at temperature TC(i+l) and exits at temperature Tc,;). The flashed vapor condenses as the main distillate and exits the flash chamber at flow rate mp; and temperature Ts;
The bottom section of the flash chamber contains the two trays of dripping brine and the additional heating surface. Superheated brine enters the uppertrayoftheflashchamber at flow rate of mbi and temperature Tb;. The brine is partially flashed in the upper tray while the rest of the brine falls down to the lowertray(s) through the additional heating surface. The falling brine will further be flashed/boiled (due to the extra superheat, large fl~hing surface area, turbulence and the active nucleation sites) and generate additional vapor. More flashing takes place at the lower tray after which the brine exits to the next stage (effect) at flow rate mb(j+l) and temperature Tb(j+l). The vapor rises (through the conventional demisters), partially to the condenser tubes and partially as a heating vapor to the next effect.
Heating vapor from the previous effect [stage (i-l)] enters the additionalheating surface, condense as additional distillate, and its latent heat of condensation is used as the heating source to heat and boil the falling brine. The additional vapor generated (due to the additional heat and due to improving fl~hing chamber effectiveness) will exit the flash chamber as the heating vapor to the next effect [stage (i+1)], similar to ME system.
Figure 4 Introduction The additional external heat (for brine reheat) could be supplied: (i) within the flash chamber (named here: internal brine reheater), (ii) through an outside heat exchanger (named here, external brine reheater); or (iii) combination of both (i) and (ii). In addition, for MSF units of large number of stages, more ME effects are utilized to increase the unit production and performance. ThecombinedMSF-MEsystemwith brine reheat may, therefore, be divided into two or more segments and each MSF-ME
segment starts with brine reheater. Each stage supplied with external heat (for brine reheat) is considered as the first ME effect superimposed on MSF base system.
Patent ( 8/28/96 ) ,~ // Dr. Hassan E. S. Fath The first effect of ME system need not to be the first stage of the MSF system. It may be the first, second, or other stages based on the optimum design arrangement ( cost, operational, scale and corrosion control,...etc.). The second effect of each ME segment need not be the next stage, but may be one of the other following stages, depending on the temperature difference required for the heating surface. Similarly for the third and following effects.
Descripfion Figure 4 shows three arrangements (as examples) of the invented combined MSF-ME
sys~em with brine rehea~ of a larger number of stages. 12 MSF stages are shown for demonstration, where the stage number is shown on the top of the Figure. The same conceptual arrangement is applied to other larger units.
In the top drawing arrangement . the external additional heat (forbrine reheat) is supplied to a single MSF stage (MSF stage number 3) and considered as the first effect of the ME system. This additional heat is supplied to the brine through one internal brine reheater. The ME second effect is superimposed on MSF-stage 5, the third effect is on MSF-stage 7 and the fourth and fifth effects on MSF stages 9 and 11 respectively. The first effect (MSF stage 3) is suppliedwithexternal heatwhilethe subsequent effects (from 2 to 5) obtain their heat source from the vapor generated in the previous effect, i.e. this drawing illustrates 1*5 effects of ME system, with single internal brine reheater, superimposed on the 12 stages of MSF system.
In the middle drawing arrangement, the invented system is divided into two segments.
Each segment consists of 6 MSF stages, 5 ME effects and one internal brine reheater.
In the first segment, the external additional heat (for brine reheat) is supplied at the second MSF stage (and considered as the first effect of the first ME segment). For the second ME segment, the external additional heat (for brine reheat) is supplied at the eighth MSF stage (the first effect of the second ME segment). The first ME effect in each segment is supplied with external heat through intemal brine reheater, and the subsequent effects in each segment (from 2 to 5) obtaintheirheat source fromthe vapor generated in the previous effect, i.e. this drawing illustrates 2 * 5 effects of ME
system, with two internal brine reheaters, superimposed on the 12stagesofMSF
system.
In the bottom drawin~ arrangement. the invented system is also divided into two di~lelll segments. The firsf segment consists of 7 MSF stages, one internal brine reheater and 4 ME effects. In this segment, the first three stages are pure MSF with enhanced fl~shing The external additional heat (forbrinereheat)issuppliedatthe fourth MSF stage (first ME effect of the this segment). The subsequent effects (the second, third, and fourth effects) obtain their additional heat from the vapor generated in the previous effect. The second segment consists of the following 5 MSF stages, one external brine reheater and 5 ME effects. The external additional heat (for brine reheat) is supplied at the eighth MSF stage (first ME effect of the second segment).
The subsequent effects (from second to fifth effects) obtain their additional heat from the vapor generated in the previous effect, i.e. this drawing illustrates 1 * 4 + 1*5 effects of ME system, one internal + one external brine reheaters, superimposed on the 12 stages of MSF system.
/~
Patent ( 8128196 ) ~, Dr. Hassan E. S. Fath 2 1 qO299 For larger number of stages of MSF units similar MSF-ME-brine reheaterscombination with dirrel e.-l break-downs could be applied.
r~gure S
In~roduction With minim~lm pressure drop of the flashing brine, the brine may havesufficient interstage pressure di~erential to raise the brine from the lower tray of one stage to the upper tray of the next stage. In case thepressuredirrelenlialisnotsufficient: (i)a reduction in the total number of MSF stages will be necessary, or (ii) the required pressure dirrere,.~ial could be attained through an additional external potential or/and pressure head per stage.
Descripfion Figure 5 presents three basic concepts to obtain higher inter-stage pressure di~eren~ials. The invented system consists of 2*4 effects of ME system, twobrinereheaters superimposed on 12 stages of MSF system. Similar conceptual arrangement will be applied to other larger or di~erent arrangement units.
Fi~ure Sa is a full stepped-down configuration. Additional interstage pressure dirreren~ial is obtained from the hydro-static (potential) head difference. Thisarrangement may need, however, a stronger supporting structure (due to thehigh elevation) in the first stages.
Figure 5b is a combination of stepped-down configuration and the utilization of circ.ll~ting pumps. In each segment (or group of stages) the additional interstage pressure dirrere"lial is obtained from the hydro-static (potential) head difference. The circul~ting pumps provide the pressure head required between each two segments and to overcome the brine reheater pressure drop. This arrangement reduces the need for stronger supporting structure. However, this should be balanced with the capital and running costs of the pumps.
Figure Sc is similar to the arrangement in Figure 5b except that the arrangement of stages in each segment is made vertical rather than the stepped-down configuration of Figure 5b. In each segment (or group of stages) the additional interstage pressure differential is obtained from the hydro-static (potential) head difference. The circlllating pumps provide the pressure head required between each two segments and to overcome the brine reheater pressure drop.
Patent ( 8128196 ) ~G /3 Dr. Hassan E. S. Fath
Claims (20)
1- A new Multi Stage Flash (MSF) distillation system of enhanced flashing,brine reheat and superimposed Multi Effect (ME) distillation system, called herein:
combined MSF-ME system with brine reheat as described in the specifications above (and described & illustrated later in the drawings Figures 2 to 5), has special features designed to increase the distillation unit capacity and production rate, and improve its performance and, therefore, reduce the fresh water production cost.
combined MSF-ME system with brine reheat as described in the specifications above (and described & illustrated later in the drawings Figures 2 to 5), has special features designed to increase the distillation unit capacity and production rate, and improve its performance and, therefore, reduce the fresh water production cost.
2- A combined MSF-ME system with brine reheat as claimed in claim 1, uses a combination of: i) the up-to-date (proven design)MSF evaporation system as a base system with different methods to improve the flash chamber effectiveness (non-equilibrium factor) and flashing evaporation rate, ii) increases the MSF system flashing range through brine reheat, i.e. supply (all or part of) the brine withadditional (external) heat in brine reheaters (located after the brine heater and/or within the flash chambers), and iii) superimposes the ME evaporation concept andsystem onto the MSF base system.
3- A combined MSF-ME system with brine reheat as claimed in claims 1 & 2, uses the up-to-date (proven design) MSF system as a base with different methods to improve the flash chamber effectiveness (non-equilibrium factor) and flashing rate, for more vapor production and better overall system performance. These methods include: i) increasing brine flashing surface area and brine turbulence (improve brine temperature gradient). For example, two (or more) trays with dripping (falling or sprayed) brine, from the upper tray to the lower tray(s), are used, as shown in Figures 2 & 3, ii) increasing the brine superheat and the number of active nucleation sites (for example; brine reheat through additional heating surface located between the trays, and steam bubbling within brine). The number of brine flashing trays may be increased more than two for more evaporation surface in larger capacity unitsand the additional heating surface may also be divided between these trays.
4- A combined MSF-ME system with brine reheat as claimed in claims 1 to 3, increases the MSF system flashing range through brine reheat, i.e. supplying thebrine with additional (external) heat after the brine heater and/or within the flash chambers. Since additional heat, for higher flashing range and more vapor production, can not be supplied to the brine before or at the brine heater (due to Top Brine Temperature (TBT) limitations), the additional heat is supplied to thebrine, in the invented system, after the brine heater (named here: brine reheat). The additional heat (brine reheat) could be supplied to the brine; (i) within the flash chamber(s), named here, internal brine reheaters (ii) through outside heat exchanger(s), named here, external brine reheaters; or (iii) combination of both (i) and (ii). Based on the optimum arrangement (design, operational, scale and corrosion control, cost,...etc.), the brine reheat could be attained at single brine reheater (top drawing of Figure 4) or being divided between two brine reheaters (middle and bottom drawings of Figure 4), or through more than two reheaters.
5- A combined MSF-ME system with brine reheat as claimed in claims 1 to 4, the additional heat could be live heating steam (for example: extracted from the turbine, part of the steam exits from a back pressure turbine, or from auxiliary steam source) or other hot fluid. Alternatively, a waste heat recovery system could be installed to utilize the plant waste heat (for example: boiler blow-down, flue gas energy,...etc.) instead of all (or part of) additional heat source.
6- A combined MSF-ME system with brine reheat as claimed in claims 1 to 5, superimposes the ME distillation concept and system on the up-to-date (proven design) MSF base system. Each stage supplied with external (additional) heat (brine reheat; through either internal or external brine reheaters) is considered the first effect of ME system superimposed on the MSF base system. The vapor generated due to: i) the improvements in flash chamber effectiveness (from claim 3), ii) due to brine reheat (from claims 4 and 5), and iii)possibly part of the main vapor generated inside the earlier flash chamber(s), is then used as a source of heat to generate more vapor in the next successive stages (effects) in a way similar to the conventional ME system, Figures 2 to 4.
7- A combined MSF-ME system with brine reheat as claimed in claims 1 to 6, the additional vapor generated from each stage is condensed inside the additional heating surface of the next effect, and used as additional distillate, Figures 2 & 3.
The latent heat of condensation is used as a source of heat for that (next) effect, similar to the conventional ME system. The main (and the additional) distillate formed in each stage (effect) is discharged through orifices to the next stage (effect) where it forms more vapor by flashing and augments the heating in that stage (effect), in a similar way to the conventional MSF (ME) systems.
The latent heat of condensation is used as a source of heat for that (next) effect, similar to the conventional ME system. The main (and the additional) distillate formed in each stage (effect) is discharged through orifices to the next stage (effect) where it forms more vapor by flashing and augments the heating in that stage (effect), in a similar way to the conventional MSF (ME) systems.
8- A combined MSF-ME system with brine reheat as claimed in claim 1 to 7, since flashing brine is at or above saturation temperature, the supplied additional (external) heat as well as heat generated in each effect are fully used for the evaporation of the additional vapor production. No heat is required to preheat the brine (from the cold seawater temperature to the boiling temperature) as in conventional ME system.
9- A combined MSF-ME system with brine reheat as claimed in claim 1 to 8, with large number of stages, more ME effects could be superimposed on the MSF base system to improve the combined systems performance and increase the production. The invented system may then be divided into two or more segments of ME system superimposed on the MSF base system segments. Each stage supplied with external heat (brine reheat; through either internal or external brine reheaters) is considered the first effect of the ME system. The first effect of each ME segment need not to be the first stage of the MSF segment.It may be the first, second, or other stages based on the optimum design and operational arrangement. The second effect need also not to be the next stage, but it may beone of other following stages, depending on the temperature differences requiredfor the optimum heating surface area. Similarly for the third and following effects as well. Typical examples of the invented system combinations are illustrated inFigure 4.
10- A combined MSF-ME system with brine reheat as claimed in claim 1 to 9, withminimum pressure drop of the flashing brine flow, the brine may have sufficient interstage pressure differential to raise the brine from the lower tray of one stage to the upper tray of the next stage. In case the pressure differential is not sufficient, either: i) a reduction in the total number of flash stages may be necessary, or ii) the required pressure differential could be attained through an additional head per stage; either potential head (stepped down stages) and/or pressure head (circulating pumps) as described in sections 4 and drawing sectionand shown in Figures 5 (a, b and c).
11- A combined MSF-ME system with brine reheat as claimed in claim 1 to 10, brine temperatures, inside the condenser tubes of the MSF system, is maintained withinoptimum design range by the adjustments of the recirculation, reject blow-down, and make-up flow rates. In case of increasing the recirculated brine flow, part of the additional generated vapor could be condensed on the condenser tubes of eachstage to maintain the system parameters near optimum values. In this case, the required additional heating surface area (for brine reheat) is reduced. Similarly, Top Brine Temperature (TBT) is also maintained within the specified (up-to-date)upper limit (for maximum flashing range and brine heater hard scale control).
12- A combined MSF-ME system with brine reheat as claimed in claims 1 to 11, using part of the main vapor generated inside the flash chambers as a source of heat (for brine reheat) will reduce the heat transfer surface area required for the main condensers as well as the brine recirculation rate (and, therefore, recirculation pump size and power), and increases the brine temperature difference across the brine heater for better heat transfer. Optimum design parameters should be obtained.
13- A combined MSF-ME system with brine reheat as claimed in claims 1 to 12 small part of the vapor generated inside the flash chambers in earlier stages (effects), could also be used for bubbling & heating the brine in later stages (in direct contact). This higher pressure vapor will first be throttled to the lower pressure stages. The bubbling superheated vapor will increase the brine superheat (in thelater stages) and will act as an additional source of active nucleation sites toenhance brine bubbling and flashing rate, i.e. improve the flash chamber effectiveness (non-equilibrium factor) and production rate. Optimum design parameters ( such as vapor rate stages number and bubbling arrangement,... etc.)should be obtained.
14 - A combined MSF-ME system with brine reheat as claimed in claim 1 to 13, theadditional heat transfer surface temperature will be maintained less than the brine heater tubes surface temperature. On the other hand, brine concentration in the flash chambers is controlled within acceptable range by the adjustments of the recirculation, reject blow-down and make-up flow rates. Since the brine containsenough antiscalent (for brine heater hard scale control), and is partially flashed and cooled down in the flash chambers of earlier stages, and with its small residence time on the additional heating surface ( brine reheaters and ME boiling surfaces), problems of high temperature hard scale deposits on these additional heating surfaces will be under control.
15- A combined MSF-ME system with brine reheat as claimed in claim 1 to 14, Due to the increase in the reheated brine temperature, the vacuum of the following stages can partially be relaxed and redistributed along the rest of reheated stages. The saturation temperature can, therefore, be increased and redistributed along the rest of reheated stages, to enhance the heat transfer across the condenser heat transfer surface. Higher heat transfer rates across the stages condensers leads to a reduction in the heat transfer surface required and/or increase in the recirculating brinetemperature that reduces the brine heater heating load requirements. These factors have the economical value of reducing plant cost; both capital cost (condensers heating surfaces) and operating cost (brine heater heating steam).
16- A combined MSF-ME system with brine reheat as claimed in claim 1 to 15, the additional vapor generated in the last stage is condensed on the condenser tubes of the heat rejection section as in conventional MSF and ME systems. Another alternative to be considered is to compress the vapor generated in the last stage, through a vapor compression system (VC), and utilize the compressed hot vapor as the source of heat for brine reheat (instead of the additional live steam).
Optimum MSF + ME + VC system combination should be obtained.
Optimum MSF + ME + VC system combination should be obtained.
17- A combined MSF-ME system with brine reheat as claimed in claims 1 to 16, with the supply of a percentage of the brine heater heat load (for brine reheat), theinvented system increases the specific unit capacity and production rate, and improves the unit performance (i.e. Gained Output Ratio-GOR), and reduces, therefore, the fresh water production cost, as compared to the present MSF
system. GOR is further increased and production costs are further reduced when waste heat is used as (part or all of) the additional (external) heat source for brine reheat.
system. GOR is further increased and production costs are further reduced when waste heat is used as (part or all of) the additional (external) heat source for brine reheat.
18- A combined MSF-ME system with brine reheat as claimed in claim 1 to 17, optimum design parameters, (such as: number of stages, number of segments, number of effects, brine reheaters's size, type and number, stage size, heat transfer surface area(s), the recirculation, reject blow-down and make-up flow rates... etc.) will be selected based on full or partial utilization of the given invented system combinations. The other design limitations should also be preserved when considering the flash chamber re-sizing, for example: i) brine velocity inside the condenser tube, ii) tube length and tube diameter, iii) stage maximum specific brine flow, and, iv) stage maximum vapor release velocity.
19- A combined MSF-ME system with brine reheat as claimed in claims 1 to 18, utilizes the main features and advantages of both MSF and ME systems simultaneously, and operates within the up-to-date existing (proven design) system's constraints and limitations. The invented system allows, also, for thepossibility of utilizing waste heat as (all or part of) the external heat source. The invented system presents, therefore, a break-through for the future generation of saline water desalination systems of high unit capacity, high production rate, better performance, and, therefore, lower fresh water production cost.
20- A combined MSF-ME system with brine reheat as claimed in claims 1 to 19, In the process of super imposing the ME system onto the MSF base system, the additional heating surface(s) inside the flash chamber of each effect may be eliminated Direct contact heating of the brine could be used instead of surface heating. The heating vapor will, therefore, be injected from the previous effect into the flash chamber and under the falling brine. In such case:
(a) The injected heating vapor will be de-pressurized and superheated through the throttling process from the previous effect pressure.
(b) Mass & heat will directly be exchanged between the superheated heating vaporand the saturated (or superheated) falling brine. The heating vapor superheat energy will be used to generate the additional vapor in this effect.
(c) The heating vapor will be condensed on the flash chamber condenser tubes, while the additional vapor will be injected into the next effect where the process is repeated.
(d) Elimination of the heating surface will reduce the total plant costs and will eliminate the problems of heating surface(s) corrosion and scale deposits.
(e) The present (or modified) methods and techniques for enhancing the heat and mass transfer between the heating vapor and falling brine may be used. Part of the heating vapor may also be injected into the brine layer(s) in order to improve the evaporation rates (due to increase the brine superheat, turbulence and the number of active nucleation sites for bubbles formation).
(a) The injected heating vapor will be de-pressurized and superheated through the throttling process from the previous effect pressure.
(b) Mass & heat will directly be exchanged between the superheated heating vaporand the saturated (or superheated) falling brine. The heating vapor superheat energy will be used to generate the additional vapor in this effect.
(c) The heating vapor will be condensed on the flash chamber condenser tubes, while the additional vapor will be injected into the next effect where the process is repeated.
(d) Elimination of the heating surface will reduce the total plant costs and will eliminate the problems of heating surface(s) corrosion and scale deposits.
(e) The present (or modified) methods and techniques for enhancing the heat and mass transfer between the heating vapor and falling brine may be used. Part of the heating vapor may also be injected into the brine layer(s) in order to improve the evaporation rates (due to increase the brine superheat, turbulence and the number of active nucleation sites for bubbles formation).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002190299A CA2190299A1 (en) | 1996-11-14 | 1996-11-14 | Combined multi stage flash-multi effect distillation system with brine reheat |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002190299A CA2190299A1 (en) | 1996-11-14 | 1996-11-14 | Combined multi stage flash-multi effect distillation system with brine reheat |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2190299A1 true CA2190299A1 (en) | 1998-05-14 |
Family
ID=4159250
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002190299A Abandoned CA2190299A1 (en) | 1996-11-14 | 1996-11-14 | Combined multi stage flash-multi effect distillation system with brine reheat |
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| Country | Link |
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| CA (1) | CA2190299A1 (en) |
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| US8709287B2 (en) | 2012-05-18 | 2014-04-29 | Air Products And Chemicals, Inc. | Water purification using energy from a steam-hydrocarbon reforming process |
| US8920771B2 (en) | 2012-05-18 | 2014-12-30 | Air Products And Chemicals, Inc. | Water purification using energy from a steam-hydrocarbon reforming process |
| US8920772B2 (en) | 2012-05-18 | 2014-12-30 | Air Products And Chemicals, Inc. | System and process for producing a H2-containing gas and purified water |
| US8956587B1 (en) | 2013-10-23 | 2015-02-17 | Air Products And Chemicals, Inc. | Hydrogen production process with high export steam |
| CN105163825A (en) * | 2012-07-16 | 2015-12-16 | 沙特阿拉伯石油公司 | Produced water treatment process at crude oil and natural gas processing facilities |
| US9309130B2 (en) | 2013-10-23 | 2016-04-12 | Air Products And Chemicals, Inc. | Integrated process for the production of hydrogen and water |
| US9539522B1 (en) | 2015-12-01 | 2017-01-10 | Kuwait Institute For Scientific Research | Combination multi-effect distillation and multi-stage flash evaporation system |
-
1996
- 1996-11-14 CA CA002190299A patent/CA2190299A1/en not_active Abandoned
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8709287B2 (en) | 2012-05-18 | 2014-04-29 | Air Products And Chemicals, Inc. | Water purification using energy from a steam-hydrocarbon reforming process |
| US8920771B2 (en) | 2012-05-18 | 2014-12-30 | Air Products And Chemicals, Inc. | Water purification using energy from a steam-hydrocarbon reforming process |
| US8920772B2 (en) | 2012-05-18 | 2014-12-30 | Air Products And Chemicals, Inc. | System and process for producing a H2-containing gas and purified water |
| CN105163825A (en) * | 2012-07-16 | 2015-12-16 | 沙特阿拉伯石油公司 | Produced water treatment process at crude oil and natural gas processing facilities |
| US10703644B2 (en) | 2012-07-16 | 2020-07-07 | Saudi Arabian Oil Company | Produced water treatment process at crude oil and natural gas processing facilities |
| US8956587B1 (en) | 2013-10-23 | 2015-02-17 | Air Products And Chemicals, Inc. | Hydrogen production process with high export steam |
| US9309130B2 (en) | 2013-10-23 | 2016-04-12 | Air Products And Chemicals, Inc. | Integrated process for the production of hydrogen and water |
| US9539522B1 (en) | 2015-12-01 | 2017-01-10 | Kuwait Institute For Scientific Research | Combination multi-effect distillation and multi-stage flash evaporation system |
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