WO2010059810A2

WO2010059810A2 - Process and system for desalinating water

Info

Publication number: WO2010059810A2
Application number: PCT/US2009/065124
Authority: WO
Inventors: Christianne Carin; T. Gene Dillahunty; Alvin W. Fedkenheuer
Original assignee: Earthrenew, Inc.
Priority date: 2008-11-21
Filing date: 2009-11-19
Publication date: 2010-05-27
Also published as: WO2010059810A3

Abstract

The present disclosure provides methods and systems for desalinating salt water. A gas turbine generator is operated to produce electricity and exhaust gases. The exhaust gases are placed in direct contact with the salt water to evaporate at least some of the water. According to some embodiments, when the evaporated water is condensed, it has a lower salt content than the salt water before it is evaporated.

Description

PROCESS AND SYSTEM FOR DESALINATING WATER

This application is being filed on 19 November 2009, as a PCT International Patent application in the name of EarthRenew, Inc., a U.S. national corporation, applicant for the designation of all countries except the US, and Christianne Carin, a citizen of Canada, and T. Gene Dillahunty and Alvin W. Fedkenheuer, both citizens of the U.S., applicants for the designation of the US only, and claims priority to U.S. Provisional patent application Serial No. 61/116,871, filed November 21, 2008.

Technical Field

The present disclosure relates generally to processes, systems and equipment for economically desalinating water.

Background

The demand for fresh water (e.g., potable water or non-potable fresh water used for other applications such as irrigation or industrial applications) is ever increasing. To meet this demand, desalination processes are used to produce fresh water from sea water or other water having a high salt content. Existing systems have been developed that use waste heat from gas turbine generators to evaporate water as part of desalination processes (e.g., see U.S. Patent Nos. 4,094,747; 7,037,430 and 7,073,337). However, such systems involve relatively large and fairly complicated operations. Moreover, such systems are not designed to be mobile. Furthermore, such systems do not provide direct contact between the water being evaporated and the hot exhaust gas from a gas turbine generator.

There is a substantial unmet need for environmentally and economically acceptable technologies for desalinating water. There is also a need for desalination systems that can readily be used for mobile applications. There is also need for efficient and simplified desalination systems. The present disclosure is directed to methods, apparatuses, and systems for meeting some or all of these needs. Summary

The present disclosure relates to methods, systems, and apparatuses for efficiently desalinating water.

The present disclosure also relates to methods, systems, and apparatuses that provide direct contact between water being desalinated and hot exhaust gas from a gas turbine generator.

The present disclosure further relates to desalination methods, systems and apparatuses that use a gas turbine generator and are relatively small in scale to enhance mobility and to facilitate installation/use on site at locations (e.g., remote locations or mobile locations) in need of power and/or fresh water.

The present disclosure further relates to desalination methods, systems, and apparatuses that are relatively simple and efficient, thereby enhancing reliability and simplifying installation.

In one aspect, the present disclosure provides a method for desalinating salt water comprising operating a gas turbine generator to produce electricity and exhaust gases, and directly contacting the salt water with the exhaust gases as part of the desalination process. hi another aspect, the disclosure provides a method for desalinating salt water. The method includes operating a gas turbine generator to produce electricity and exhaust gases. The method also includes using the electricity on site or selling the electricity to a power company or both. The method further includes directly contacting the salt water with the exhaust gases from the gas turbine generator to evaporate the water, thereby separating the water from the salt, hi certain embodiments the exhaust gases directly contacting the salt water can have a temperature greater than 500°F, or greater than 700°F, or greater than 1 ,000⁰F.

In still another aspect of the present disclosure, the present disclosure provides an apparatus for drying and/or treating salt water comprising a gas turbine in combination with a heating vessel (also referred to herein as "evaporation chamber") adapted for receiving the salt water and also for receiving the exhaust gases from the gas turbine, hi one embodiment, outside air is precluded from entering the heating vessel as the exhaust gas flows through the heating vessel and treats the salt water. In other embodiments, at least some outside air may be introduced into the heating vessel during treatment of the salt water with the exhaust gas. The heating vessel optionally includes structures adapted for drying and/or treating the salt water by direct contact of the salt water with the exhaust gases. In certain embodiments the gas turbine and heating vessel can be portable or can be provided as part of a portable processing unit or units. The above aspects and other aspects will be apparent to one of skill in the art from the disclosure herein.

Brief Description of the Drawings

Fig. 1 is a schematic diagram of a system for desalinating salt water in accordance with the principles of the present disclosure; Fig. 2 is a schematic diagram of another system for desalinating salt water in accordance with the principles of the present disclosure; and

Figs. 3-10 are schematic views of various heating vessel configurations.

Detailed Description The present disclosure also provides new technology in the form of processes, apparatuses, and systems that allow for the desalination of salt water in an efficient and economically viable way.

Figure 1 shows a desalination system 24 in accordance with the principles of the present disclosure. The system 24 includes a turbine generator 60 that supplies hot exhaust gas to a heating vessel arrangement 62 used to heat salt water provided from a source of salt water 40. Example sources of salt water can include seawater, salt water removed from the ground during drilling operations, or other sources such as mining operations. The turbine generator 60 includes a combustor 64 where a fuel such as natural gas is combusted. The exhaust gas from the combustor 64 drives an exhaust turbine 66 that rotates a drive shaft 67. The drive shaft 67 drives a compressor turbine 70 that moves intake air under compression into the combustor 64. An air filter 72 is typically used to clean the intake air fed into the combustor. The drive shaft 67 also drives an electrical generator 74 for generating electrical power that can be used to power various operations performed on site and/or can be sold to another party (e.g., a utility company). The hot exhaust gas from the turbine is preferably used to provide heat to the heating vessel arrangement 62 for evaporating water from the salt water. In one embodiment, the hot exhaust gas is passed though the heating vessel arrangement 62 and comes in direct contact with the salt water within the heating vessel arrangement.

Preferably, salt water is drawn from the source of salt water 40 and transferred (e.g., piped/pumped) to the heating vessel arrangement 62 where the water is evaporated. Optionally, a pre-treatment device 41 such as a filter, strainer, centrifuge or other separation device can be used to remove at least some suspended solids or other materials from the salt water prior to the salt water being transferred into the heating vessel arrangement 62. The water vaporized at the heating vessel arrangement 62 can be condensed at a condenser 61 which can also be used to pre-heat the water from the salt water source 40 before the salt water is transferred into the heating vessel arrangement 62. The condensed fresh water can be treated (e.g., filtered with a system such as a reverse osmosis filtration system 42) to remove unwanted substances from the exhaust gas stream that may have dissolved in the water after condensation.

The salt in the salt water can be handled in a variety of ways. For example, in one embodiment, only a portion of the water of the salt water provided to the heating vessel arrangement 62 is evaporated, while the remainder of the water passes through the heating vessel arrangement 62 and can be returned to the source of salt water (e.g., the sea). In such embodiments, the salt water provided to the heating vessel arrangement 62 has a lower salt concentration than the salt water returned to the source of salt water, hi certain embodiments, the salt concentration of the water returned to the source of salt water is in the range of 10 to 100% greater than the salt concentration of the salt water initially provided to the heating vessel. In certain embodiments, the salt concentration of the water returned to the source of salt water is at least 10 % greater than the salt concentration of the salt water initially provided to the heating vessel. Li certain embodiments, the salt concentration of the water returned to the source of salt water is at least 20 % greater than the salt concentration of the salt water initially provided to the heating vessel. In certain embodiments, the salt concentration of the water returned to the source of salt water is at least 30 % greater than the salt concentration of the salt water initially provided to the heating vessel, hi certain embodiments, the salt concentration of the water returned to the source of salt water is at least 40 % greater than the salt concentration of the salt water initially provided to the heating vessel.

In such embodiments, salt is not precipitated during the evaporation process and need not be handled. Instead, all of the salt in the salt water provided to the heating vessel arrangement 62 is returned to the source of salt water along with the unevaporated water.

An optional silencer 65 can be provided downstream of the turbine generator 60. Typically, the silencer 65 may be used for startup, shutdown, or during those times when the turbine generator 60 is operating in a mode (e.g., a heating vessel bypass mode) in which the exhaust gas does not pass through the heating vessel arrangement 62. However, the heating vessel arrangement 62 will function as a silencer during normal operation of the system. In certain embodiments, a blower or other device is used to lower exhaust pressure within the heating vessel arrangement and the turbine generator to maximize turbine efficiency.

Fig. 2 shows another desalination system 24' in accordance with the principles of the present disclosure. The system 24' is the same as the system 24 except a steam powered generator 71 is provided between the turbine generator 60 and the heating vessel arrangement 62. In some embodiments not all the exhaust gases are needed for the heating vessel operation, hi such embodiment the excess exhaust gas can be diverted to provide heat required in other steps in the systems or in other nearby operations . hi some embodiments, it may be desirable to collect salt as part of the desalination process. For example, it may be desirable to collect salt for the purpose of selling the salt as a product (e.g., sea salt). Alternatively, under certain conditions, factors such as environmental concerns may prevent all of the salt from being returned back to the source of salt water.

According to the present disclosure, an efficient way of providing the hot gases for contact with salt water is to use the exhaust from a gas turbine, and preferably a gas turbine electric generator. The gas turbine can be fueled from locally available conventional fuel sources, because conventional fuels provide an efficient, reliable, and controllable operation of the gas turbine. The electricity produced from the gas turbine generator can be sold back into the local power grid as a revenue source and/or can be used internally in the operation of the system or in other nearby operations as a supplemental source of power. For example the supplemental power can be used to generate electrical heat for drying operations, run high pressure pumps used in reverse osmosis processes, or run electric motors do power auxiliary equipment.

In certain embodiments, it can be more efficient to merely sell the electric power produced to the local power grid. This enables varying the operation of the processes and equipment of systems of the type disclosed herein in the most efficient and effective manner for treatment of salt water to produce the desired quality and quantity of products without concern for or being constrained by any particular minimum or necessary level of electricity output or the need for an unchanging level of electricity output.

One feature used by certain embodiments of the present disclosure (e.g., the embodiments of Fig. 1) is that the gas turbine and the heating vessel arrangement are connected together such that introduction of outside air into the heating vessel arrangement is precluded, and the heating vessel arrangement preferably receives the exhaust gases directly from the gas turbine. In certain embodiments (e.g., the embodiment of Fig. 1), it is preferred that 100% of the gas turbine exhaust gases are passed into at least a first heating vessel and, for more efficient operation, preferably without passing through any intervening heat exchanger, silencer, or other equipment in order that the first heating vessel receives the maximum heating from the gas turbine exhaust.

Referring to Figures 3-8, the salt water can be sprayed into the heating vessel arrangement 62. Preferably, the sprayed water makes direct contact with hot exhaust from the gas turbine 60 within the heating vessel arrangement 62, and preferably outside air is substantially precluded from entering the heating vessel arrangement 62. The water can be sprayed in various directions within the heating vessel arrangement by structures such as one or more spray nozzles.

In certain embodiments, the water can be sprayed upwardly within the heating vessel arrangement 62, downwardly within the heating vessel arrangement 62, horizontally within the heating vessel arrangement 62, angled relative to horizontal within the heating vessel arrangement 62, or can be sprayed in combinations of directions. Hot exhaust flow within the heating vessel arrangement 62 can flow upwardly within the heating vessel arrangement 62, downwardly within the heating vessel arrangement 62, horizontally within the heating vessel arrangement 62, or angled relative to horizontal within the heating vessel arrangement 62. The water can be sprayed in the same direction as the direction of exhaust flow, in the opposite direction of exhaust flow (i.e., counter flow), laterally across the direction of exhaust flow, or angled across the direction of exhaust flow.

Figure 3 illustrates an embodiment where the water is sprayed into the vessel from the left side of the vessel towards the right side of the vessel and the exhaust gas being directed into the vessel from the right side towards the left side of the vessel. In the depicted embodiment the flow of the water and gas are generally in opposite directions and generally horizontal.

Figure 4 illustrates an embodiment where the water is sprayed into the vessel from an upper portion of the vessel towards a lower portion of the vessel and the exhaust gas being directed into the vessel from the right side towards the left side of the vessel. In the depicted embodiment the flow of the water and gas are generally in perpendicular directions.

Figure 5 illustrates an embodiment where the water is sprayed into the vessel from an upper portion of the vessel towards a lower portion of the vessel and the exhaust gas being directed into the vessel from the lower portion of the vessel towards an upper portion of the vessel. In the depicted embodiment the flow of the water and gas are generally in opposite directions and the flow is generally vertical.

Figure 6 illustrates an embodiment where the water is sprayed into the vessel from a lower portion of the vessel towards an upper portion of the vessel and the exhaust gas being directed into the vessel from the lower portion of the vessel towards an upper portion of the vessel. In the depicted embodiment the flow of the water and gas are generally in the same directions and the flow is generally vertical.

Figure 7 illustrates an embodiment where the water is sprayed into the vessel from an upper portion of the vessel towards a lower portion of the vessel as well as from both sides of the vessel, and the exhaust gas being directed into the vessel from the lower portion of the vessel towards an upper portion of the vessel as well as from the right side of the vessel. In the depicted embodiment the flow of the water and gas are from multiple directions and in multiple relative orientations.

Figure 8 illustrates an embodiment where the water is sprayed into the vessel from an upper portion of the vessel towards a lower portion of the vessel, and the exhaust gas is directed into the vessel in a swirling flow pattern from the lower portion of the vessel towards an upper portion of the vessel. For example, a side inlet 103 can direct exhaust into the vessel in a direction generally tangent to a curved outer surface of the vessel to cause an upward swirling action of the exhaust flow about a central axis 105 of the vessel, hi embodiments wherein exhaust flow enters the heating chamber in a direction parallel to the axis 105, vanes 100, paddles or other flow-turning structures can be provided within the vessel to cause the exhaust to swirl about the axis 105.

According to alternative embodiments the vessel can take many other shapes. For example, the vessel could be a stationary "porcupine" drum dryer with or without scrapers and/or agitator plates and/or paddles; the vessel could be a rotary drum with or without internal scrapers, agitation plates, and/or paddles; the vessel could be a triple pass stepped drying cylinder or rotary drum heating vessel system with or without scrapers and/or agitator plates and/or paddles; the vessel could be a rotary drum heating vessel system with or without steam tubes and with or without scrapers and/or agitator plates and/or paddles, hi some embodiments the vessel could be configured as a turbo-dryer or turbulizer system; a conveyor dryer system with or without scrapers and/or agitator plates and/or paddles; an indirect or direct contact dryer system with or without scrapers and/or agitator plates and/or paddles, etc. Referring to figures 9-10, some alternative configurations for providing water to the vessel other than by spraying the water into the vessel are shown. Referring to figure 9, according to one embodiment the water can be transferred into the heating vessel arrangement 62 by a conveyor arrangement including one or more containers (e.g., open topped containers) capable of holding water and configured for allowing water to be evaporated from the containers upon entry into the heating vessel arrangement 62. hi such an arrangement, salt precipitated in the containers can be removed from the heating vessel arrangement by the conveyor arrangement and collected at a location outside the heating vessel arrangement.

Referring to figure 10, in some embodiments water is poured into the vessel and diverted by deflector to increase the surface area of the water that comes into direct contact with the exhaust gas. In the depicted embodiment the exhaust gas enters the bottom of the vessel, moves through the moving water, and exits the top of the vessel. In certain embodiments, fans 104 blowers or other structures can be used to enhance exhaust flow through the heating vessel.

The exhaust output from the turbine generator 60 is preferably connected to the heating vessel arrangement 62 by a connection conduit 63. An optional air inlet (not shown) can be in the conduit 63, in the heating vessel arrangement 62, or elsewhere for purging the heating vessel arrangement 62 or other system, for startup or shutdown or for other reasons, particularly when either the exhaust gases or salt water are not present in the heating vessel arrangement 62. However, when both are present, any such air inlet is preferably closed and not used in order to substantially preclude the introduction of air into the heating vessel arrangement 62.

When it is desired to collect or concentrate the salt, the heating vessel arrangement can be configured to facilitate collection of the salt. For example, the heating vessel arrangement can have inclined surfaces or a funnel-like configuration at its bottom to accumulate the salt at a more discrete location from which the salt can be removed from the heating vessel arrangements. To remove the salt from the heating vessel arrangement, the heating vessel arrangement can be operated to drive all or almost all the water from the salt so that a dried salt is precipitated within the heating vessel arrangement. After a predetermined amount of salt has been precipitated, the system can be stopped temporarily while the precipitated salt is removed manually or with the use of collection and hauling equipment. Li other embodiments, a conveyor arrangement can be used to remove precipitated salt from the heating vessel arrangement without requiring the system to be temporarily stopped. In still other embodiments, the salt can be pumped or otherwise removed from the heating vessel arrangement as part of as highly salt concentrated brine or sludge. Once removed from the heating vessel arrangement, the concentrated brine can be further processed on site to produce a sellable product, can be transported to another location for further processing, or can be disposed of in an environmentally acceptable manner, hi still other embodiments, the salt water can be held in a reservoir within heating vessel arrangements, and the hot exhaust gas can flow over the top of the salt water in the reservoir. In still other embodiments, the salt water can be held in troughs or other structures within the heating vessel arrangement 62.

Referring back to figures 3-6 and 8-10, examples of vessels configured to collect salt are described in greater detail. For example, referring to figure 3 the bottom of the vessel is configured to collect salt brine and direct the brine out of the vessel, hi particular, the bottom of the vessel is angled and directs liquid to a drain 108. Referring back to figures 4 and 10, the bottoms of the vessels are sloped so that the dried salt or salt brine is directed to one edge of the vessel and can be conveniently removed. Referring back to figure 8, the bottom of the vessel is funnel shaped to allow the salt or salt brine to drain therethrough. Referring to figure 5, the bottom surface 110 of the vessel includes a conveyer that can be moved periodically or continuously to remove salt that collects thereon. Referring to figure 6, a tray 112 is provided at the bottom of the vessel which can be periodically removed and emptied.

In certain embodiments heating vessel arrangements employed in systems of the type described herein can be any type or configuration that is suitable for receiving salt water and turbine exhaust gases. In some embodiments the vessel is configured to not allow a significant amount of outside air to enter the heating chamber/chambers of the heating arrangement where the exhaust gases contact the salt water. In some embodiments the design of the gas turbine exhaust connection to the heating vessel is arranged to preclude any significant amount of outside air from entering the heating vessel arrangement to help heating efficiency. It will be recognized that in some of these types of operations, not all outside air can be excluded. Therefore, the terms as used herein which refer to "preclude introduction of air," and the like, are used in the above operational context and with the recognition and intended meaning that the air entering the system along with the salt water or exhaust gases is not intended to be precluded

In other embodiments, alternate sources of hot gases other than a gas turbine can be used and connected to the heating vessel arrangement, such as the exhaust from conventional oil or gas burners and reciprocating engines. Of course, such an alternate or additional source of hot gases can optionally be connected to the heating vessel arrangement and used to supplement the exhaust gases output of the gas turbine to provide additional heat input capacity for the heating vessel arrangement if needed for start up, shut down, or surge load conditions, or for backup in the event the gas turbine goes off line.

According to some embodiments the vessel is an off-the-shelf or modified commercially available heating vessel. Some commercially available vessels that can be adapted for use with the present disclosure include, for example: Scott AST Dryer Systems, Simon Dryer Ltd. Drum dryers, Wyssmont Turbo Dryer systems, Duske Engineering Co., Inc., Energy Unlimited drying systems, The Onix Corporation dehydration systems, International Technology Systems, Inc. direct or indirect dryer systems, Pulse Drying Systems, Inc., the CE. Rogers drying and evaporator systems including the mechanical vapor recompression (MVR) system, and MEC Company dryer systems. Further examples of heating vessels useful in or that can be adapted for use in this invention are disclosed in U.S. Pat. No. 5,746,006 to Duske et al. and U.S. Pat. No. 5,570,517 and U.S. Pat. No. 6,367,163 to Luker, the disclosures of which are incorporated herein by reference in their entirety.

In certain embodiments, heating vessel arrangements of the type disclosed herein include a heating vessel that also functions as the silencer for the gas turbine or other engine providing the hot exhaust gases. It is well known that gas turbines can produce a high level of noise impact on the nearby environment. Stationary gas turbines used for electric power production or other purposes are usually required by local, state and federal regulations to have silencers installed to muffle the noise of the exhaust of the gas turbine to acceptable levels. Such silencers have the economic disadvantages of cost and creating back pressure on the gas turbine exhaust, which reduces the efficiency of the gas turbine operation. One advantage of systems disclosed herein, due to the connection between the gas turbine exhaust and the heating vessel preferably being closed to outside air, is that the heating vessel functions effectively as a silencer for the gas turbine. This is at least in part a result of the internal configuration construction of the heating vessel acting in combination with the presence of the salt water, which combination is effective in absorbing and muffling the gas turbine exhaust noise. This is also due to the downstream end of the heating vessel also being closed to the atmosphere, because the steam and off gases from the heating vessel are collected for condensation, cleaning, recycling, and for heat recovery in the downstream processing in a closed system before being vented to the atmosphere. It will be apparent to one skilled in the art that capability for venting at various points in the process and the equipment system may be desirable to accommodate startup, shutdown, upset or feedstock variability, but will normally be operated as a closed system having only final product output and clean gas venting. The turbine exhaust can optionally be partially or temporarily wholly diverted to other downstream units, bypassing the heating vessel, when needed for supplemental heat in other process units or for startup, shut-down, or upset.

In certain embodiments of the present disclosure, the steam and off gases can be pulled from the discharge end of the heating vessel arrangement by an appropriate fan, vent blower, etc., to provide a reduced pressure at the upstream entrance of the heating vessel arrangement, thereby reducing the back pressure on the turbine exhaust. This increases the efficiency of operation of the gas turbine and is made possible because the connection between the gas turbine exhaust and the heating vessel is not open to outside air. It will be understood that the commercial system design may include a vent or even a conventional silencer connected by tee or other configuration into the connection between the gas turbine exhaust and the heating vessel for use during startup, shut down, or upset operation, but would not be employed in the normal operating configuration for the process and apparatus of this invention as described above. To achieve best efficiency, it is preferred that the connection between the gas turbine exhaust and the heating vessel inlet have no obstructions in order to deliver the exhaust gases to the heating vessel with a minimum of heat and energy loss between the gas turbine and the heating vessel. It will also be recognized from this disclosure, that the operation of a gas turbine generator will preferably be controlled for optimal efficiency or economics for water evaporation, which may not be the optimal or best gas turbine operating conditions for electricity production. The electricity production is a cost recovery revenue stream for the system, but the overall economics of the operation of this invention may be better under gas turbine operating conditions that favor optimum exhaust heat output for efficient heating vessel operation and downstream production of products having desired properties, and disfavor electricity production. Determination of such operating conditions for a particular installation of this invention will be apparent to one skilled in the art following the teachings herein.

The operating conditions and procedures for the heating vessel arrangement will be apparent to one skilled in the art following the teachings herein of the present disclosure. The typical turbine exhaust gas temperature entering the heating vessels forming part of the heating vessel arrangement may be in the range of about 500°F to about l,500°F. hi certain embodiments, the hot exhaust gas provided to a heating vessel has a temperature greater than 900°F, or greater than l,000°F, or greater than 1250°F, or greater than 1500°F, or in the range of about 1,000 to 1,500⁰F.

The term "gas turbine" is used herein to mean and include any turbine engine having a compressor turbine stage, a combustion zone, and an exhaust turbine stage that is capable of producing exhaust gas temperatures of at least 500⁰F, preferably at least about 700⁰F, more preferably at least about 900⁰F and most preferably greater than about 1,000⁰F. Gas turbines are the heat source preferred for use in systems disclosed herein because of their efficient operation and high heat output.

The gas turbine generator is further preferred due to the production of energy by the generator, which energy can be utilized or sold to improve the economics of the operation of the systems of this invention. The generator will typically be an electric generator due to the convenience of using and/or selling the electricity produced. However, the generator can be any other type of energy generator desired, such as a hydraulic pump or power pack that can drive hydraulic motors on pumps, augers, conveyors and other types of equipment. The heat requirements and the system economics will determine whether a gas turbine or gas turbine generator is used. If it is desired to have higher temperature exhaust gases and higher heat output from a given smaller size gas turbine, it may be desired to use a gas turbine instead of a similar size gas turbine generator. Compared to the gas turbine, the gas turbine generator further expands and cools the exhaust gases in absorbing energy to drive the generator, where in a gas turbine that energy is contained in higher temperature gases available for use in the heating vessel arrangements of the type disclosed herein. This can be an option when it is economically more important in the practice to have small (e.g., truckable) high temperature units than to have the revenue stream or economic benefit of the electricity or other energy production by the gas turbine.

Turbines or turbine generators useful in systems of the type described herein can be fueled from any available source with any suitable fuel for the particular turbine. The preferred and conventional fuels are sweet natural gas, diesel, kerosene, and jet fuel because the gas turbines are designed to run most efficiently on good quality fuels of these types and because of their common availability, particularly at remote operations, where the units of this disclosure may be located. However, other fuels that can be used to fuel the turbine include methane, propane, butane, hydrogen and biogas, and bioliquid fuels (such as methane, oils, diesel, and ethanol).

Examples of commercially available gas turbines and gas turbine generators useful in systems of the type disclosed herein include the following (rated megawatt (MW) outputs are approximate): Rolls Royce Gas Turbine Engines Allison 501-KB5, -KB5S or -KB7 having a standard condition rated output of 3.9 MW;

European Gas Turbines Tornado having rated output of 7.0 MW; Solar Mars 90 having rated output of 9.4 MW and Solar Mars 100 having rated output of 10.7 MW; Solar Tarus 60 having rated output of 5.5 MW and Solar Tarus 70 having rated output of 7.5 MW.

For a nominal product output capacity of 2.5 metric tons/hr (2,500 kg/hr) a gas turbine generator size of about 4 megawatt (MW) can be used, depending on the heat insulation and heat recovery efficiencies designed into the overall system. For small single semitrailer or truck systems, the units may be scaled smaller. For smaller product output systems, such as a 0.3 metric ton/hr product output, small gas turbines, such as the Solar Saturn 0.8 MW, Solar Spartan 0.2 MW or Capstone 0.5 MW or 0.3 MW generators, can be used depending on system efficiencies and required heat input ranges. Li certain embodiments gas turbines used in systems in accordance with the principles of the present disclosure can have a size less than 4 MW, or less than 3 MW, or less than 2 MW, or less than 1 MW, or less than .5 MW. Further information regarding gas turbine dying systems can be found at U.S. Patent Nos. 7,024,796 and 7,024,800, the entire disclosures of which are hereby incorporated herein by reference.

It will be recognized that systems according to this disclosure can also be designed to utilize the exhaust gas heat from reciprocating engines, such as gasoline or diesel generators. In certain embodiments, all of the air conveyed by the compressor turbine of the gas turbine is directed to the combustion chamber. In certain other embodiments, the exhaust gas from the combustion chamber of the gas turbine is not mixed with air that bypasses the combustion chamber. The preceding embodiments are intended to illustrate without limitation the utility and scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made to the embodiments described above without departing from the true spirit and scope of the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A desalination method comprising: directly contacting sea water with exhaust gases from a gas turbine to provide evaporated water; and condensing the evaporated water to provide desalinated water.

2. The process of claim 1 , further comprising filtering the sea water before the sea water is evaporated, and filtering the desalinated water after the desalinated water has been condensed.

3. The process of claim 1 , wherein the sea water is preheated by the evaporated water in a heat exchanger.

4. The process of claim 1, wherein the turbine is used to power an electric generator.

5. The process of claim 1, wherein the exhaust gases contact the sea water within a heating vessel, wherein a first portion of the sea water is evaporated at the heating vessel and a second portion of the sea water is returned to a source of the sea water.

6. The process of claim 5, wherein the salt concentration of the sea water returned to the source of sea water is at least 10 % greater than the salt concentration of the sea water initially provided to the heating vessel.

7. The process of claim 1, wherein the exhaust gases contact the sea water within a heating vessel, wherein substantially all of the sea water is evaporated at the heating vessel, and wherein salt precipitated within the heating vessel is collected for distribution as sea salt.

8. The process of claim 1 , wherein the exhaust gases contact the sea water within a heating vessel, and wherein the sea water is sprayed into the heating vessel.

9. The process of claim 8, wherein the water is sprayed in a direction that is generally opposite to a flow direction of the exhaust gas within the heating vessel.

10. The process of claim 8, wherein the water is sprayed in a direction that is generally the same as a flow direction of the exhaust gas within the heating vessel.

11. The process of claim 8, wherein the water is sprayed in a direction that is generally across a flow direction of the exhaust gas within the heating vessel.

12. The process of claim 1, wherein the exhaust gases contact the sea water within a heating vessel, and wherein the sea water is cascaded though at least a portion of the heating vessel.

13. The process of claim 1 , wherein the exhaust gases contact the sea water within a heating vessel, and wherein the sea water is carried into the heating vessel by a conveyor system that also removed precipitated salt from the heating vessel.

14. The process of claim 1 , wherein the exhaust gases contact the sea water within a heating vessel, and wherein the heating vessel has a sloped floor that facilitates collecting precipitated salt within the heating vessel.

15. A desalination system comprising: a gas turbine including an exhaust outlet; an evaporation chamber connected to the exhaust outlet such that exhaust from the gas turbine flows within the evaporation chamber; and a spraying arrangement for spraying salt water into the evaporation chamber such that the salt water contacts the exhaust from the gas turbine and at least a portion of the salt water is evaporated.

16. The system of claim 15, wherein the evaporation chamber includes a lower surface that is slope to facilitate the collection of precipitated salt.

17. The system of claim 15, further comprising a conveyer configured to remove precipitated salt from the evaporation chamber.

18. The system of claim 15, wherein the evaporation chamber includes a water outlet for removing non-evaporated salt water from the evaporation chamber.

19. The system of claim 15, wherein the salt water is sprayed into the evaporation chamber in a direction that is generally opposite to a flow direction of the exhaust within the evaporation chamber.

20. The system of claim 15, wherein the salt water is sprayed into the evaporation chamber in a direction that is generally the same as a flow direction of the exhaust within the evaporation chamber.

21. The system of claim 15, wherein the salt water is sprayed into the evaporation chamber in a direction that is generally across a flow direction of the exhaust within the evaporation chamber.

22. The system of claim 15, wherein the exhaust is swirled within the evaporation chamber.