Technical Field

The following invention relates to systems, methods and processes for concentrating a lithium brine to support extraction of lithium therefrom. More particularly, this invention relates to systems which utilize combustion of a hydrocarbon fuel with oxygen and directly contacting products of this combustion with a lithium brine to enhance a concentration of lithium within the brine and otherwise produce power and other useful byproducts for lithium extraction and other purposes.

Background Art

The transition from use of fossil to renewable energy is rapidly expanding the need to produce lithium for battery storage and for use in electric vehicles. Global lithium demand is anticipated to grow exponentially in the period from 2020-2040. On the supply side, investment in new sources is historically capital intensive with lead times of five to eight years before production can fully ramp up. There will therefore be a significant and long period of market deficit that is anticipated to already occur before 2025.

The preferred method of production has traditionally been from salt flats located in the “Lithium Triangle” between Argentina, Bolivia and Chile in South America. To be commercial, the concentration of lithium in the associated brine water is typically greater than 4,000 parts per million (ppm). An alternative source is the mining of hard rock spodumene - an ore that typically contains from 6 to 9% lithium and is primarily sourced from Western Australia.

Combined, these two regional resources represent four-fifths of global lithium supply, with the remainder being sourced from China (10%), Zimbabwe (3%) and the United States (2%).

The United States production is strategically important but small and historically limited to mining in North Carolina, brine from geothermal power production in the Salton Sea of Southern California, and brine from associated bromide production in Smackover, Arkansas. Despite lithium being globally abundant - and ranked third in the periodic table - it is only rarely found in concentrations that are commercially viable. The world oceans are the largest resource containing an estimated 5,000 times more lithium than the land-based resources; however, the concentration is extremely low at about 0.2 ppm. With current technology and the current commercial environment, it is presumed that concentration needs to be above 400 ppm to be viable.

There are significant resources of lithium identified at lower concentrations in brine aquifers and associated underground water with natural gas and oil production facilities world-wide. It is therefore desirable to provide a system and method that more efficiently produces lithium from such less concentrated sources. Accordingly, a need exists to efficiently convert low concentration lithium brine into high concentration lithium brine in a way that is compatible with such geologic formations and which utilizes the resources available at such sources, while providing useful byproducts.

Disclosure of the Invention

This invention provides a system and method for utilizing oxygen combustion to increase the concentration of lithium in produced brine so that previously noncommercial lithium can be commercially extracted using current lithium extraction technology. Targeted brine concentrations for the invention in one embodiment are in the range of 50 up to and above 400 ppm of lithium.

Byproducts of the oxygen production and combustion include nitrogen (when oxygen is provided from an air separation unit), carbon dioxide and water that can be utilized to extract hydrocarbon resources that may include produced brine and thereby creating an additional revenue stream from the system. Furthermore, the oxygen combustion can be combined with equipment such as turbines and steam generators. Such equipment can be located on site and used to generate electricity and steam to provide to the lithium extraction facility and/or to the grid. Furthermore, the fuel for oxygen combustion can be imported to the facility from off-site (e.g. a natural gas pipeline), or produced on-site as part of the hydrocarbon recovery system, or a combination of both. Likewise, the exhaust gas provides clean water vapor that can be condensed into makeup water providing excess water for other applications, or for sales. In an illustrative embodiment, a system and method for producing lithium from low concentration lithium brine comprises a combustor that operates using hydrocarbon-based fuel and oxygen and low concentration lithium brine to provide a flow of steam, CO ₂ and gaseous lithium brine. A gas separator assembly is operatively connected to an exhaust outlet of the combustor, constructed and arranged to separate CO ₂ and concentrated brine water. The separator assembly can include a condenser that condenses the water from water vapor in the exhaust. The condenser directs at least some condensed water to other system processes. The carbon-based fuel can comprise at least one of a biogas or biomethane, sourced from a renewable fuel source, a carbon-based fuel from a fossil fuel source, a carbon-based fuel from synthetic chemical processes, or other hydrocarbon fuel.

With this invention in one example embodiment, a first lithium brine is fed into a system which outputs a second lithium brine, with the second lithium brine having a higher concentration of lithium than the first lithium brine. The first lithium brine is also referred to as a low concentration lithium brine because it has a lower concentration of lithium than the second lithium brine. The second lithium brine is referred to as a high concentration lithium brine, meaning that it has higher concentration than the low concentration lithium brine.

To increase the concentration of lithium from the low concentration lithium brine to the high concentration lithium brine, the low concentration lithium brine is routed through the combustor, such as a oxy-fuel combustion gas generator, and then routed through the gas separator, also called a steam/bnne separator. This steam/brine separator has an outlet for high concentration lithium brine and an outlet for steam and carbon dioxide. The second lithium brine has a higher concentration of lithium than the first lithium brine, because a water content is less than it is with the first lithium brine. In one example, 80 to 90 percent of the water has been removed, so that lithium concentration has been increased by nearly (or more than) an order of magnitude.

More specifically, the gas generator has oxygen and a hydrocarbon fuel combusted therein and the low concentration lithium brine is introduced into the oxy- fuel combustion gas generator through cooling fluid inlets of the direct steam gas generator. Output of the gas generator is thus at least steam, carbon dioxide and lithium. In the steam/brine separator, enough steam and carbon dioxide are removed from the exhaust of the gas generator, so that the remaining stream (establishing the second lithium brine) has a higher concentration of lithium than that which was entered into the direct steam gas generator (as the original low concentration lithium brine).

This steam/brine separator can function based on a variety of different known prior art technologies. In one embodiment, the steam/brine separator is at least partially in the form of a separator condenser which has a cooling pathway associated therewith which cools the exhaust from the gas generator within the steam/brine separator condenser. This cooling is sufficient to cause lithium brine to condense within the steam/brine separator condenser, and a liquid outlet discharges the high concentration lithium brine from the separator condenser. Other forms of steam/brine separators could alternatively be utilized to separate steam and CO ₂ from lithium and/or lithium brine, such as cyclone separators or hybrid cyclone and condensing separators.

In one embodiment, the low concentration lithium brine originates from a subterranean space such as a depleted oil well or a saline aquifer. Such subterranean spaces are known to be good locations for carbon sequestration in the form of injecting CO ₂ into such subterranean spaces, both for long term geological storage of the CO ₂ away from the atmosphere, and also potentially for enhanced oil/natural gas (or other hydrocarbons) extraction from such a subterranean space. Many such subterranean spaces include a amount of lithium therein sufficiently high to warrant extraction of lithium therefrom for beneficial use of the lithium downstream of a lithium extraction plant, which can extract lithium from high concentration lithium brine and provide a useful source of lithium, such as for battery manufacture.

While such a subterranean space could merely have low concentration lithium brine pumped therefrom (such as in the case where the subterranean space is a saline aquifer), in many instances such a pumping process will also pull up some amount of produced hydrocarbons along with the low concentration lithium brine. In such instances, this combined liquid pumped from the subterranean space can be routed through a three phase oil separator (or some other form of hydrocarbon separator) which outputs hydrocarbons, such as liquid hydrocarbons from one outlet and gaseous hydrocarbons from a separate outlet. A remaining outlet of the three phase oil separator provides at least a portion of the low concentration lithium brine fed into the gas generator.

In one embodiment, at least some of the hydrocarbons separated by the three phase oil separator are routed to a fuel inlet of the gas generator. In such an embodiment, any lithium and/or water entrained within the hydrocarbons when exiting the three phase oil separator will still end up passing into the direct steam oxyfuel gas generator for beneficial use, and not be lost or require as much further processing of hydrocarbons outputted from the three phase oil separator.

The output of the three phase oil separator can be identified as at least a portion of a source of a first lithium brine having a lower concentration than the second lithium brine. This source of low concentration lithium brine could be routed directly to the cooling fluid inlet(s) of the direct steam gas generator. However, most preferably, the low concentration lithium brine from the source is first routed through a basic water/brine treatment. It is also beneficial that this low concentration brine be preheated before entering the direct steam gas generator. Such a preheating can as one option occur by routing the low concentration lithium brine along the cooling pathway of the separator condenser. This cooling pathway is separate from the exhaust gas pathway of the separator condenser which is downstream from the gas generator. As an alternative, such preheating can occur through heat transfer with a steam/CO ₂ outlet of the separator that is downstream of the gas generator exhaust.

Such a heated low concentration lithium brine could then be passed into the cooling fluid inlet of the direct steam gas generator without further modification, or could be coupled with water from some other source (and optionally also carbon dioxide) such as to maintain the cooling fluid passing into the gas generator through the cooling fluid inlets, with desired characteristics (such as temperature, specific heat and suitable concentrations of constituents which might otherwise foul the cooling fluid and inlets into the direct steam gas generator).

The gas generator is of a type which includes a fuel inlet and an oxygen inlet which fuel and oxygen are combusted together to produce steam and carbon dioxide (see for instance gas generators by Clean Energy Systems, Inc. of Rancho Cordova, California). Additional steam is produced within the direct steam gas generator by boiling cooling fluid entering into the direct steam gas generator through the cooling fluid inlets. The cooling fluid (in this case the low concentration lithium brine) is directly “vaporized” along with the combustion products of the fuel and oxygen also entering the gas generator. The low concentration lithium brine acting as the cooling fluid keeps walls of the gas generator from exceeding maximum temperatures which the walls of the gas generator can withstand. However, the temperatures are preferably significantly super heated beyond minimum temperatures for boiling of water into steam, at which temperatures the lithium brine is also converted into a gaseous state.

The oxygen provided into the gas generator is preferably substantially pure oxygen. In one embodiment, the oxygen is provided from an air separation unit. The air separation unit could involve liquefaction of the air, such as to produce substantially 100% oxygen, or could utilize some other technology, such as pressure swing adsorption, to achieve at least about 95% oxygen as an oxidizer for the gas generator (and with a small argon fraction). At a minimum, the oxygen inlet supplies the gas generator with an oxidizer that is a majority oxygen, and a significantly higher percentage of oxygen than the oxygen present within unmodified air.

The fuel inlet of the gas generator receives a hydrocarbon fuel. This fuel could be natural gas or could be some other hydrocarbon gas. The hydrocarbon gas could be a syngas, such as that produced from gasifying a solid fuel or a liquid fuel, or could be a low BTU gas from some source. In one embodiment, at least some of the fuel entering the fuel inlet of the direct steam gas generator is a hydrocarbon material which was extracted from the subterranean space along with the low concentration lithium brine. For instance, if the subterranean space is a depleted oil well, oil, and often also entrained natural gas, are produced. From an outlet of a three phase oil separator, the hydrocarbon gas can be then routed to a blender and combined with other hydrocarbon fuel (such as natural gas), to provide an input gaseous fuel having a desired energy content.

The exhaust of the gas generator is a mixture of steam, carbon dioxide and lithium, at least. Carbon dioxide is produced by combustion of the hydrocarbon fuel with oxygen. Some of the steam is produced as one of the combustion products of combustion of the hydrocarbon fuel with oxygen, and some of the steam is from water contained in the low concentration lithium brine which was entered into the gas generator through the cooling fluid inlets. Some CO ₂ could also be in the low concentration lithium brine. This combined exhaust gas exits the gas generator and is then routed to the inlet of the steam/brine separator. In one embodiment, power production occurs through a turbine expander through which the exhaust gas of the gas generator is routed. While such a turbine expander is between the gas generator and the steam separator, as one option, typically any such turbine would be instead downstream of a steam/CO ₂ output of the steam separator.

Such a turbine expander can be coupled to an electric generator which can then provide power for various parts of the system, including pumps within the system. Also, power produced by the turbine can be fed to the air separation unit and/or to the lithium extraction plant, which receives the high concentration lithium brine exiting the steam/brine separator. In this way, the system does not need an external source of power (or less additional power) and a lithium extraction plant can operate more economically. The turbine could expand a working fluid heated by the exhaust if it is preferred to keep the gas generator exhaust from passing through the turbine. Multiple turbines could be provided in stages as a further option, such as to maximize power output.

While the steam/bnne separator could be any of a variety of different separators, in one embodiment, this separator is a separator condenser. Cooling fluid passing through the steam/brine separator causes the exhaust from the gas generator to be cooled until at least a portion of the water condenses into a liquid. As noted above, as one option, the low concentration lithium brine can be routed along this cooling circuit of the steam/brine separator before it enters the cooling fluid inlet(s) of the gas generator.

Typically, as condensation occurs within the steam/brine separator, the water begins to condense first, and the lithium brine also condenses. The steam/brine separator is configured so that conditions are maintained therein where substantially all (or at least about 90%) of the lithium has condensed back to the form of part of a dissolved salt or other dissolved state within the first water to condense within the steam/brine separator. Conditions within the steam/brine separator are maintained so that significant portions (preferably a majority) of the steam, and all of the CO ₂ are still gaseous. This steam and carbon dioxide gas is discharged from a gas outlet of the steam/brine separator and the high concentration brine is also separated out from a liquid outlet of this separator. The steam/brine separator could utilize other technologies (temperature control, geometry /height selection, cyclonic flow inducement, pressure control, catalyst use, etc.), either separate from or in addition to those described herein for such separation. The high concentration lithium brine which leaves the steam/brine separator as a liquid can then be passed to a lithium extraction plant which can then further process the high concentration lithium brine into a marketable state. As an alternative, the high concentration lithium brine could merely be output from the system of this invention as a marketable output product.

The steam and carbon dioxide leaving the steam/brine separator could in one embodiment merely be discharged into the surrounding environment, it being recognized that water/steam and carbon dioxide are naturally occurring substances already present within the atmosphere. However, as CO ₂ is a greenhouse gas, it is beneficial in most circumstances to avoid discharge of at least some of the CO ₂ produced by this system. Accordingly, the steam and CO ₂ exiting as a gas from the steam/brine separator are preferably contained and further utilized in the system of this invention and/or sequestered from the atmosphere. Such further processing can include routing to a power turbine for power extraction, before routing to a condenser.

This condenser condenses the steam into liquid water which can then be discharged separate from the gaseous carbon dioxide. This “produced” water can be discharged from the system as a beneficial byproduct, and, having just condensed, is substantially pure water and suitable for use in a variety of different ways, either within the system(s) of this invention, or separate from this system.

The CO ₂ typically has some amount of moisture remaining therein. The CO ₂ can be further processed, such as by cycles of compression, intercooling and recompression, to both condense further water out of the CO ₂ and to pressurize the CO ₂ . The pressurized CO ₂ can then be injected into a subterranean space or outputted from the system, such as for commercial sale.

Once the CO ₂ has been dried and pressurized a desired amount, the CO ₂ is preferably routed into a subterranean space which in one embodiment is the same subterranean space which originally produced the low concentration lithium brine. Delivering CO ₂ into the space helps to pressurize the space and to cause changes within the subterranean space which can cause hydrocarbons to be more readily extracted therefrom (often called “enhanced oil recovery” or “EOR”). At a minimum, the space is pressurized somewhat so that less power is required to pump the low concentration lithium brine therefrom. Should the subterranean space have hydrocarbons therein, the hydrocarbons can be beneficially also produced and can be optionally used to power the system of this invention through combustion within the direct steam gas generator. Generally, such CO ₂ use can be referred to as “Carbon Capture Utilization and Storage” (or “CCUS”). Other uses for the CO ₂ include use in the lithium extraction plant, such as to form Li ₂ CO ₃ or other lithium and carbon containing compounds, or use in rock weathering, or other CCUS actions. The CO ₂ could also be sold.

As can be seen from a study of this system overall, the system outputs no pollutants. No exhaust stack discharges to the atmosphere. Water is produced. Power is optionally produced. Furthermore, the system can utilize at least somewhat the hydrocarbons produced as part of the system and process of this invention, so that at least a portion of power required to operate the system of this invention is provided by the system itself. Furthermore, depleted oil wells and other subterranean spaces which contain hydrocarbons therein and which also contain lithium can have both the hydrocarbons and the lithium extracted therefrom and beneficially utilized, rather than the lithium remaining in an unconcentrated state and of little or no economic value.

Brief Description of Drawings

Figure 1 is a schematic view of a system for lithium extraction with an oxy-fuel combustor according to one example embodiment of this invention and following one method of this invention.

Figure 2 is a schematic view of a first alternate system and method of that which is shown in Figure f.

Figure 3 is a schematic view of a second alternate system and method of that which is shown in Figure 1.

Figure 4 is a schematic view of a third alternate system and method of that which is shown in Figure 1. Best Modes for Carrying Out the Invention

Referring to the drawings, wherein like reference numerals represent like parts throughout the various drawing figures, reference numeral 10 (Figure 1) is directed to a system for lithium extraction utilizing an oxy-fuel gas generator combustor 20 according to a first example embodiment. The system 10 feeds low concentration lithium brine into the gas generator 20 where it is raised to a high temperature and then passed through a steam/brine separator 40, which outputs a high concentration lithium brine for use such as within a lithium extraction plant 50.

In essence, and with particular reference to Figure 1, basic details of the system and method of this invention are described, according to an example embodiment. The system 10 includes a gas generator 20 such as that disclosed in U.S. Patent Nos. 5,680,764; 5,709,077; 5,715,673 ; 5,956,937; 6,170,264; 6,206,684; 7,021,063; 7,637,109; 7,882,692; 8,522,871; 8,631,658; and 8,833,080, each incorporated herein by reference in their entirety, and available from Clean Energy Systems, Inc. of Rancho Cordova, California, U.S.A. The gas generator 20 combusts oxygen with a hydrocarbon fuel to produce products of combustion, including steam and carbon dioxide. The gas generator 20 includes coolant inlets 24 which feed low concentration lithium brine into the gas generator 20. An optional turbine 30 or other expander can take the high temperature, high pressure steam, carbon dioxide and lithium (as well as potentially other elements/molecules) and output power, while also reducing pressure and temperature of the gas mixture. This gas is then fed to a steam/brine separator 40 which includes a gaseous vent 44 and a drain/exit 46 for at least partially condensed fluids. These at least partially condensed fluids are in the form of a lithium brine with a higher concentration of lithium in the brine than that brine which was introduced into the gas generator 20, because the heating thereof caused a portion of the water in the low concentration original lithium brine to be removed as steam.

The high concentration lithium brine can be outputted, such as to a lithium extraction plant 50. The steam and carbon dioxide gases exiting the steam/brine separator 40 are passed to a condenser, where the water and CO ₂ are at least partially separated. Wet CO ₂ can be further dehydrated and compressed in a compressor 70 and then a mostly CO ₂ fraction can be injected into a geological formation 80 for sequestration away from the atmosphere or otherwise beneficially used. In one embodiment, the geological structure into which the CO ₂ is injected causes production of low concentration lithium brine therefrom, potentially also along with hydrocarbons. A three phase separator 90 can be utilized to separate liquid and gas hydrocarbons from each other and also to separate low concentration lithium brine therefrom. This low concentration lithium brine can be further treated in a brine treatment 95, optionally pumped to a higher pressure and preheated, such as via a heat exchanger with heat from the steam/brine separator 40 (or condenser 60) and then fed to the coolant inlets 24 of the gas generator 20 to complete the cycle. Gaseous hydrocarbons from a three phase oil separator 90 can optionally be used as at least a portion of natural gas or other hydrocarbon fuel for combustion with oxygen within the gas generator 20.

More specifically, and with continuing reference to Figure 1, particular details of this invention are described according to this first example embodiment. The system 10 utilizes an oxy-fuel combustion gas generator 20 to enhance a concentration of a lithium brine. Low concentration lithium brine is fed into the gas generator 20 through coolant inlets 24 thereof, or as an alternative, merely into an entry downstream of the gas generator 20 where the lithium brine is caused to have its temperature greatly increased through direct contact (or indirect via heat exchanger) with the steam and carbon dioxide products of combustion within the gas generator 20. References herein to “low concentration lithium brine” and “high concentration lithium brine” indicate a first brine with a lesser amount of lithium therein then the second brine. Furthermore, low concentration lithium brine can in at least some embodiments mean a lithium brine which has a lower concentration than that which is generally considered to be economical to process into a useful lithium product. In other embodiments, reference to “low concentration lithium brine” can indicate a lithium brine which has a concentration of lithium which is less than an optimal concentration lithium brine, such that it is at least somewhat beneficial that the concentration of lithium within the low concentration lithium brine be increased.

In this embodiment, the gas generator 20 includes an injector 22 which is fed with oxygen from an oxygen supply line 12 and fuel from a fuel supply line 14. The fuel supply line 14 is coupled to a fuel blender 16 which, in one embodiment, combines natural gas such as pipeline natural gas with natural gas or other gaseous hydrocarbons provided from other sources. These other sources could include, in one embodiment, gas produced from a geological structure 80 which also contains lithium brine therein. Other sources of hydrocarbons for the gas generator 20 could include synthetic gas, such as that produced from coal gasification or other sources of low BTU hydrocarbon gas. Hydrogen gas could also be provided as the fuel as an option, and is thus considered to be within the definition of a hydrocarbon fuel, whether it comprises only a portion of fuel with which the gas generator 20 is fired or if it comprises all of the fuel with which the gas generator 20 is fired.

In one embodiment, the oxygen supply line 12 is coupled to an air separation unit 2 which receives air for an inlet 4. The air separation unit 2 acts on the air to produce a nitrogen stream, discharged through a nitrogen outlet 6, which is separate from the oxygen supply line 12. Buffer tanks would typically be provided associated with the air separation unit 2, for storage and buffering of excess oxygen.

The gas generator 20 produces a very high temperature and at least somewhat high pressure gas stream including steam and carbon dioxide. The gas generator 20 includes strategically located coolant inlets 24 to moderate this high temperature, and to increase the volume of steam produced by the gas generator 20. These coolant inlets 24 can be at least partially located within the injector 22 of the gas generator 20, and at various different stages at different spacings away from the injector 22, and even at or beyond an outlet 26 from the gas generator 20. While the gas generator 20 could initially start on pure water at these coolant inlets 24, to provide the lithium brine concentration benefits of this invention, the low concentration lithium brine is introduced into the gas generator 20 through these coolant inlets 24. Low concentration lithium brine is caused to boil into a steam and high temperature lithium combination, which lithium portion can have various states such as ionized, atomic, and/or remaining within some molecule, the forms of lithium being that which can exist at the temperatures and pressures which exist within the gas generator 20 (and while one in the presence of high temperature and high pressure steam and carbon dioxide).

Downstream from the gas generator 20 an outlet 26 feeds an input 32 of a turbine 30 or other expander. In alternate embodiments, such a turbine 30 or other expander could be located elsewhere within the system 10 (such as powered by steam/CO ₂ vented from the separator 40) or omitted. Beneficially, the turbine 30 handles gases passing therethrough which are above condensation temperatures and pressures. The turbine 30 or other expander includes a power output shaft 36 which can drive an electric generator 38 or can provide rotational shaft power, which can provide power in 54 for a lithium extraction plant 50, as described in detail below. Turbine 30 includes an output 34 of typically still at least somewhat superheated gas including steam, carbon dioxide, and (in this embodiment) a gaseous lithium brine component.

This gas mixture is introduced into the steam/brine separator 40. The steam/brine separator 40 can be configured as a conventional steam separator which includes an entry 42, typically at a middle elevation thereof, and a vent 44, typically at an upper portion thereof. A drain/exit 46 is provided typically at a lower portion thereof. A coolant loop 45 can optionally be provided for removal of heat from the steam separator 40 and to encourage (by such heat removal) the condensation of high concentration lithium brine therein. This high concentration lithium brine which would mostly typically be in a liquid form, then passes out of the drain/exit 46 from the steam separator 40, typically with a pump 48 associated therewith. This pump 48 can feed a brine entrance 52 of a lithium extraction plant 50.

The lithium extraction plant 50 is configured according to the prior art to take high concentration lithium brine, such as at the brine entrance 52. The plant 50 can also utilize power, such as provided at the power input 54 from the turbine 30 (either electric power from a generator or mechanical power or process steam or heat if needed by the plant 50), and then outputs lithium product 58 for sale or further processing or utilization within lithium utilizing downstream systems (e.g. battery production).

The gaseous vent 44 of the steam separator 40 is fed to a condenser 60 (optionally through a turbine or other expander). This condenser 60 includes a cooling loop 66, such as fed by cooling water, which reduces a temperature of the gaseous steam and carbon dioxide until at least a major fraction of the steam has condensed into water. The water is then simply discharged through water drain 68 from the condenser 60. A CO ₂ outlet 64 is provided for carbon dioxide and typically also some steam discharged from the condenser 60. The gas inlet 62 is typically spaced from the CO ₂ outlet 64 to encourage water condensation, rather than discharge as steam along with the CO ₂ . The water outlet 68 is a source of excess water produced by the system 10 and can be beneficially utilized for a variety of different purposes, including within the lithium extraction plant, or as start up water for use when starting the gas generator 20, or for municipal, agricultural or industrial uses.

The wet CO ₂ from the CO ₂ outlet 64 is passed to a CO ₂ compressor/dehydrator. In one embodiment, this element of the system 10 is in the form of a series of compressors and intercoolers which intercoolers remove the heat of compression and result in higher and higher compression of the wet CO ₂ . At higher pressures, but avoiding significantly higher temperatures, more and more of the steam condenses into water for removal from the CO ₂ . A CO ₂ pump/compressor 72 downstream of the wet CO ₂ element 70 further enhance pressure of the CO ₂ which can be a gas, liquid, or super critical fluid, or combination thereof, which can then be discharged from the system 10 for other beneficial uses. According to one embodiment depicted herein, the CO ₂ is routed through a CO ₂ injector 76 into a geological formation 80.

In one embodiment, the geological formation 80 is a subterranean space which is a suitable location for sequestration of the CO ₂ away from the atmosphere. In another embodiment, this geological formation 80 can contain hydrocarbons and be suitable for enhanced oil (and/or hydrocarbon gas recovery) caused by injection of the CO ₂ therein. According to one embodiment, such as that depicted in Figure 1, the geological formation 80 contains lithium brine therein. A pump (or gravity drain) or other output line 84 can interact with a well/access 82 for removal of lithium brine, and potentially also produced hydrocarbons which can be gaseous and/or liquid.

These produced hydrocarbons, along with the lithium brine, are passed along to a three phase oil separator 90 or other separation equipment. With the three phase oil separator 90, oil and other non-gas liquids (HGLS), which are separate from the lithium brine, are discharged through an oil out 92. A hydrocarbon gas out 94 allows for the hydrocarbon gases to be discharged, and can potentially be blended at a blender 16 with natural gas or other hydrocarbon fuels to feed the fuel supply 14 of the gas generator 20. The three phase oil separator 90 also includes a lithium brine out 91. This lithium brine is typically a low concentration lithium brine, which benefits from being concentrated at least somewhat.

The lithium brine can go through a treatment facility 95, such as to remove various non-lithium constituents and contaminants therefrom. Typically, this low concentration lithium brine is then preheated by passing along the coolant loop 45 of the steam/brine separator 40. As one option, this lithium brine could also be routed through the cooling loop 66 of the condenser 60, which would typically occur before passing through the coolant loop 45 of the steam/brine separator 40. The lithium brine is thus preheated before it is routed to the coolant inlets 24 of the gas generator 20.

While low concentration lithium brine could merely be heated to boil off some of the water as steam and less concentrate lithium within the brine, such a basic boiler is typically not economical. However, by utilizing the oxy-fuel combustion gas generator 20, the system can beneficially utilize hydrocarbons produced from the geological formation 80 (or other hydrocarbons) and output useful power, as well as concentrated lithium brine and also CO ₂ , as well as excess water, many of which byproducts (including power, CO ₂ and water) can also be beneficially utilized to improve the economics of the system 10, relative to merely boiling the low concentration lithium brine.

With particular reference to Figure 2, a first alternate system 100 is described. Many elements of the system 100 can match those of the system 10 described in detail above. An oxygen supply 110 and fuel supply 115 are combusted within a gas generator 120. Lithium brine injection 180 enters the gas generator 120 to produce an output from the gas generator 120 of steam, carbon dioxide and high temperature lithium brine. In this embodiment, a conventional steam separator 140 receives these hot fluids downstream of the gas generator 120. Clean steam and CO ₂ is discharged from the steam separator 140. Other primarily liquid constituents are discharged from the steam separator separate from the clean steam and CO ₂ . This mostly liquid output is primarily concentrated lithium brine.

This brine has typically been concentrated by five times or more through this process. Various useful purposes can have the clean steam/CO ₂ applied thereto, and the concentrated lithium brine can be utilized in an extraction plant for extraction of lithium. Heat within the clean steam/CO ₂ can be utilized to preheat the low concentration lithium brine after it is pumped to pressure at a pump 170 and fed to the lithium brine injection 180 at the gas generator 120. Such a feed water heater 160 further assists in the process of heating (along arrow Q) the lithium brine preparatory for its concentration with the gas generator 120.

With particular reference to Figure 3, details of a second alternate system 200 of the system 10 is described. With the system 200 an oxygen supply 210 and fuel supply 215 are fed to an injector 222 of a gas generator 220. In this embodiment, optional hot gas processing downstream of a gas generator 220 occurs downstream of outlet 226, resulting in a high concentration lithium brine discharge 228 ahead of a turbine 230. The heat exchanger 240 can exchange heat between a line 242 downstream of the turbine 230 and a feed water location 244. Gases discharged from the turbine 230 can go through a first separator condenser 250 and optionally a second separator condenser 260, which each can further discharge high concentration lithium brine therefrom. Finally, remaining steam and carbon dioxide can be at least partially discharged from the system with remaining portions pumped up to pressure, combined with more low concentration lithium brine from source 280, and through pump 290 to be returned as coolant to the gas generator 220.

With particular reference to Figure 4, details of a third alternative embodiment system 300 are described. In this embodiment, an air separation unit 305 supplies oxygen to an oxygen supply 310, which feeds oxygen along with fuel from the fuel supply 315 to a gas generator 320. Coolant lines 399 also feed coolant into the gas generator 320. Discharge from the gas generator 320 is fed into a separator 340. High concentration lithium brine drains from the separator 340 to a lithium extraction plant 350, while gaseous steam and CO ₂ discharged from the steam separator can be passed to an optional turbine 330. This steam and CO ₂ can then be routed through a heat exchanger, such as a feed water heater 355 exchanging heat (along arrow Q) between line 357 and line 359, which line 359 can preheat low concentration lithium brine being routed back to coolant lines 399 of the gas generator 320. The further cooled steam and CO ₂ leaving the feed water heater 355 can be passed to condenser 360. The condenser 360 can discharge water separate from CO ₂ .

The CO ₂ can be utilized within the lithium extraction plant 350, discharged from the system as a salable byproduct or routed to a geological formation 380 for sequestration away from the atmosphere, and potentially also for enhanced oil recovery and especially for recovery of lithium brine from the geological formation 380. An optional oil separator 390 can separate oil and potentially also hydrocarbons from the lithium brine produced from the geological formation 380. This source of low concentration lithium brine 395 from the geological formation 380 is pumped up to pressure by pump 397, before preheating along line 359 within the feed water heater 355, and can then be passed to mixer 398, where it can be mixed with water 396 to obtain a desired character, before being utilized as coolant within the coolant lines 399 of the gas generator 320.

This disclosure is provided to reveal a preferred embodiment of the invention and a best mode for practicing the invention. Having thus described the invention in this way, it should be apparent that various different modifications can be made to the preferred embodiment without departing from the scope and spirit of this disclosure. When embodiments are referred to as “exemplary” or “preferred” this term is meant to indicate one example of the invention, and does not exclude other possible embodiments. When structures are identified as a means to perform a function, the identification is intended to include all structures which can perform the function specified.

Industrial Applicability

This invention exhibits industrial applicability in that it provides a system for concentrating a low concentration lithium brine into a high concentration lithium brine such as to support lithium extraction therefrom.

Another object of the present invention is to provide a system for generating electrical or mechanical power from combustion of a hydrocarbon fuel while simultaneously concentrating a lithium brine into a higher concentration.

Another object of the present invention is to provide a method for enhancing a concentration of a lithium brine.

Another object of the present invention is to provide an economical method and system for extracting lithium from a lithium brine which has a lower than optimal lithium concentration therein.

Another object of the present invention is to provide a method for facilitating extraction of lithium brine from a geological structure.

Another object of the present invention is to provide a method and system for facilitating extraction of lithium brine from a geological structure while simultaneously sequestering CO ₂ into that geological structure.

Another object to the present invention is to provide a system and method for facilitating extraction of lithium brine from a geological structure while simultaneously sequestering CO ₂ into that geological structure and optionally also extracting hydrocarbons from that structure.

Another object of the present invention is to provide a method and system for facilitating extraction of lithium brine from a geological structure while simultaneously sequestering CO ₂ into the geological structure and optionally also extracting hydrocarbons from that structure, and while generating useful electrical and/or mechanical power for use in lithium extraction processes and/or other purposes.

Another object of the present invention is to provide a method and system for facilitating extraction of lithium brine from a geological structure while simultaneously sequestering CO ₂ into the geological structure and optionally also extracting hydrocarbons from that structure, and generating useful electrical and/or mechanical power for use in lithium extraction processes and/or other purposes while also producing clean water. Another object of the present invention is to provide a system and method which combusts a hydrocarbon fuel with oxygen to produce combustion products including steam and carbon dioxide, and then separating at least some of the carbon dioxide from the steam and utilizing the carbon dioxide to enhance a lithium extraction process.

Another object of the present invention is to provide a method and system which combusts a hydrocarbon fuel with oxygen to produce combustion products including steam and carbon dioxide, which are then combined with low concentration lithium brine and then separating steam therefrom and carbon dioxide, to leave the lithium brine with a higher concentration than it had previously, and to also use the CO ₂ produced by virtue of the combustion with the hydrocarbon fuel to refine lithium into a carbon and oxygen containing molecule such as lithium carbonate.

Other further objects of this invention which demonstrate its industrial applicability, will become apparent from a careful reading of the included detailed description, from a review of the enclosed drawings and from review of the claims included herein.