DEVICE FOR CHEMICAL REACTIONS INCLUDING ACID AND / OR BASE, AND RELATED SYSTEMS AND METHODS

Abstract

A device for chemical reactions containing an acid and / or a base, and related systems and methods are generally described. In some embodiments, the method includes generating a base near a first electrode (e.g., a cathode) and an acid near a second electrode (e.g., an anode) electrochemically connected to the first electrode. In certain embodiments, the method includes collecting the acid and / or base. In some examples, the method includes storing the acid and / or base.

Description

[Technical field]

[0001] Related Applications This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 62 / 818,604, filed March 14, 2019, U.S. Provisional Patent Application No. 62 / 887,143, filed August 15, 2019, and U.S. Provisional Patent Application No. 62 / 962,061, filed January 16, 2020, all of which are incorporated by reference in their entirety and for all purposes.

[0002] Technical Field DETAILED DESCRIPTION Devices for chemical reactions involving acids and / or bases, and related systems and methods, are generally described. Summary of the Invention [Means for solving the problem]

[0003] overview A device for chemical reactions involving an acid and / or a base, and related systems and methods are generally described. In some embodiments, the method includes generating a base in the vicinity of a first electrode (e.g., a cathode) and an acid in the vicinity of a second electrode (e.g., an anode) electrochemically connected to the first electrode. In certain embodiments, the method includes collecting the acid and / or base. In some examples, the method includes storing the acid and / or base. In some embodiments, the method includes reacting the acid and / or base in a chemical dissolution (e.g., reacting the acid with a metal carbonate, such as CaCO3, to generate a metal ion, such as calcium ion, and / or carbonate ion). In certain embodiments, the method includes reacting the acid and / or base in a precipitation reaction (e.g., reacting the base with a metal ion, such as calcium ion, to generate a metal hydroxide, such as Ca(OH)2). In some embodiments, the metal hydroxide can be used in a cement manufacturing process.

[0004] In some cases, the production of acid near the second electrode and / or the production of base near the first electrode produces gas (e.g., CO2, H2, and / or O2). In certain cases, one or more of the gases can be collected, sold, used in downstream processes, and / or fed back to the system. In some cases, any gas produced is used by the system (e.g., increasing the pH gradient between the electrodes), so the production of acid near the second electrode and / or the production of base near the first electrode results in a reduced amount of gas, no gas, and / or no net amount of gas produced. In certain embodiments, for example, during periods of low electricity costs, the acid produced near the second electrode and / or the base produced near the first electrode can be used to produce hydrogen gas and / or oxygen gas, for example, during periods of high electricity costs.

[0005] Systems and methods of the present invention for forming a precipitate in a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) are also described. Forming a precipitate in a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) can be achieved, for example, by dissolving a chemical compound (e.g., a metal salt) in a first region (e.g., an acidic region) of the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) and collecting a precipitate containing one or more elements (e.g., metals) from the chemical compound (e.g., a metal salt) in a second region (e.g., an alkaline region) of the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In certain embodiments, the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) is present in an electrochemical cell and is established and / or maintained by electrolysis (e.g., electrolysis of water). According to some embodiments, after the precipitate is collected, it is heated in a kiln to produce a cement, such as Portland cement. The subject matter of the present invention includes, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0006] Certain aspects relate to a method, in some embodiments, the method includes operating a reactor in a first mode, the first mode including producing a base from a first electrode, producing an acid from a second electrode electrochemically connected to the first electrode in the reactor, and collecting the acid and / or the base.

[0007] In certain embodiments, the method includes operating the reactor in a first mode, the first mode including producing a base from a first electrode, producing an acid from a second electrode electrochemically connected to the first electrode in the reactor, collecting the acid and / or base, and reacting the collected acid and / or base in a chemical dissolution and / or precipitation reaction.

[0008] In some embodiments, the method includes operating the reactor in a first mode, the first mode including producing a base and hydrogen gas from a first electrode, producing an acid and oxygen gas from a second electrode electrochemically connected to the first electrode in the reactor, and allowing the oxygen gas to diffuse and / or be transported to the first electrode and / or allowing the hydrogen gas to diffuse and / or be transported to the second electrode, and allowing the oxygen gas to be reduced by the first electrode and / or allowing the hydrogen gas to be oxidized by the second electrode.

[0009] In some embodiments, the method includes generating a base and a dihalide in a first reactor, generating an acid in a second reactor, collecting the acid, collecting the base, performing a chemical dissolution with the acid and / or base, and performing a precipitation reaction with the acid and / or base.

[0010] Certain aspects relate to a system. In certain embodiments, the system comprises a first electrode, a second electrode electrochemically connected to the first electrode, and a device configured to collect an acidic product proximate the second electrode and / or a basic product proximate the first electrode.

[0011] In some embodiments, the system includes a first electrode, a second electrode electrochemically connected to the first electrode, a first device configured to collect an acidic product proximate the second electrode and / or a basic product proximate the first electrode, and a second device configured to react the collected acidic product and / or the collected basic product.

[0012] In certain embodiments, the system includes a first electrode configured to produce a base and hydrogen gas, and a second electrode electrochemically connected to the first electrode, the second electrode configured to produce an acid and oxygen gas, the system configured to allow oxygen gas to diffuse and / or be transported to the first electrode and / or allow hydrogen gas to diffuse and / or be transported to the second electrode, the system configured to allow oxygen gas to be reduced by the first electrode and / or hydrogen gas to be oxidized by the second electrode.

[0013] In some embodiments, the system includes a first reactor configured to produce a base, a dihalide, and hydrogen gas, a second reactor configured to produce an acid, a first device configured to collect the acid proximate the second reactor and perform a chemical dissolution and / or precipitation reaction with the acid, and a second device configured to collect the base proximate the first reactor and perform a chemical dissolution and / or precipitation reaction with the base.

[0014] Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying drawings. In the event that the specification and documents incorporated by reference include a conflict and / or inconsistency with the present disclosure, the specification shall control.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments of the present invention are described, by way of example, with reference to the accompanying drawings, which are schematic and are not intended to be drawn to scale. In the drawings, each identical or nearly identical component illustrated is typically represented by a single numeral. For clarity, not every component is labeled in every drawing, and not every component of each embodiment of the present invention is shown unless illustration is necessary to enable a person skilled in the art to understand the invention. [Brief description of the drawings]

[0016] [Figure 1A] FIG. 1A is a schematic diagram of a system including a first electrode, a second electrode, and a device, according to certain embodiments.

[0017] [Figure 1B] FIG. 1B is a schematic diagram of a system including a first electrode, a second electrode, and two devices, according to certain embodiments.

[0018] [Figure 1C] FIG. 1C is a schematic diagram of a system including a first electrode, a second electrode, a device, and a separator, according to certain embodiments.

[0019] [Figure 1D] FIG. 1D is a schematic diagram of a system including a first electrode, a second electrode, and three devices, according to certain embodiments.

[0020] [Figure 1E]FIG. 1E is a schematic diagram of a system including a first electrode, a second electrode, and six devices, according to one particular embodiment.

[0021] [Figure 1F] FIG. 1F is a schematic diagram of a system including a first electrode, a second electrode, an apparatus, and a kiln according to one particular embodiment.

[0022] [Figure 2A] FIG. 2A is a cross-sectional schematic diagram of a system for producing hydrogen gas and oxygen gas, comprising a first electrode and a second electrode, according to a specific embodiment.

[0023] [Figure 2B] FIG. 2B is a cross-sectional schematic diagram of a system for producing hydrogen gas and oxygen gas, comprising a first electrode, a second electrode, and a separator, according to certain embodiments.

[0024] [Figure 2C] FIG. 2C is a cross-sectional schematic diagram of a system for producing hydrogen gas and oxygen gas, comprising a first electrode, a second electrode, a separator, and two devices, according to certain embodiments.

[0025] [Figure 2D] FIG. 2D is a schematic diagram of a system for producing hydrogen gas and oxygen gas, comprising a first electrode, a second electrode, a separator, two devices, and a kiln, according to certain embodiments.

[0026] [Figure 3A] FIG. 3A is a schematic diagram of a system comprising two reactors, according to one particular embodiment.

[0027] [Figure 3B] FIG. 3B is a schematic diagram of a system comprising two reactors, where the first reactor comprises a first electrode and a second electrode, according to certain embodiments.

[0028] [Figure 4A] FIG. 4A is a schematic diagram of a two-chamber system according to one particular embodiment.

[0029] [Figure 4B] FIG. 4B is a schematic diagram of a two-chamber system in which CaCO is dissolved in one chamber and Ca(OH) is precipitated in the other chamber, according to a specific embodiment.

[0030] [Figure 5A] FIG. 5A is a schematic diagram of a reactor operating in high voltage mode, according to certain embodiments.

[0031] [Figure 5B] FIG. 5B is a Pourbaix diagram illustrating the high voltage mode.

[0032] [Figure 6A] FIG. 6A is a schematic diagram of a reactor operating in low voltage mode, according to certain embodiments.

[0033] [Figure 6B] FIG. 6B is a Pourbaix diagram illustrating the low voltage mode.

[0034] [Figure 7] FIG. 7 is a plot of electricity cost against time for a 1 kW alkaline electrolyser operated at 1.2 V (solid line) and for electrolysers consuming the same amount of current operated at 2 V when electricity costs are >0.05$ / kWh and at 0.4 V when electricity costs are <0.05$ / kWh (dotted line).

[0035] [Figure 8A] FIG. 8A is a schematic diagram of a reactor operating in low voltage mode A, according to certain embodiments.

[0036] [Figure 8B] FIG. 8B is a Pourbaix diagram illustrating low voltage mode A.

[0037] [Figure 9A] FIG. 9A is a schematic diagram of a reactor operating in low voltage mode B, according to certain embodiments.

[0038] [Figure 9B] FIG. 9B is a Pourbaix diagram illustrating low voltage mode B.

[0039] [Figure 10A] FIG. 10A is a schematic diagram of a reactor operating in a fuel cell mode, according to certain embodiments.

[0040] [Figure 10B] FIG. 10B is a Pourbaix diagram illustrating the fuel cell mode.

[0041] [Figure 11] FIG. 11 is a flow chart illustrating the electrolysis of water at neutral pH to produce acid / base for producing precipitated hydroxides in accordance with some embodiments, according to certain embodiments.

[0042] [Figure 12] FIG. 12 is a flow chart illustrating electrolysis of an alkali halide electrolyte to produce an acid / base for producing precipitated hydroxide in accordance with certain embodiments.

[0043] [Figure 13A]13A-13B are diagrams illustrating that OH- is charge balanced by cations in an electrolyte that pass through a diaphragm or membrane, according to certain embodiments. FIG. 13A is an illustration showing that at a first electrode (e.g., cathode) of reactor 1, water is reduced to yield OH- (alkaline solution) and H2(g), according to certain embodiments. FIG. 13B is an illustration showing that at a first electrode (e.g., cathode) of reactor 1, O2 is reduced to yield OH- (alkaline solution), according to certain embodiments. [Figure 13B] 13A-13B are diagrams illustrating that OH- is charge balanced by cations in an electrolyte that pass through a diaphragm or membrane, according to certain embodiments. FIG. 13A is an illustration showing that at a first electrode (e.g., cathode) of reactor 1, water is reduced to yield OH- (alkaline solution) and H2(g), according to certain embodiments. FIG. 13B is an illustration showing that at a first electrode (e.g., cathode) of reactor 1, O2 is reduced to yield OH- (alkaline solution), according to certain embodiments.

[0044] [Figure 14A] 14A-14B are diagrams illustrating chemical dissolution and precipitation reactions, according to certain embodiments. Fig. 14A is a schematic diagram showing a dihalide reacting with hydrogen gas to produce a desired acid, according to certain embodiments. Fig. 14B is a schematic diagram showing a dihalide reacting with water to produce a desired acid, and oxygen as a by-product, according to certain embodiments. [Figure 14B] 14A-14B are diagrams illustrating chemical dissolution and precipitation reactions, according to certain embodiments. Fig. 14A is a schematic diagram showing a dihalide reacting with hydrogen gas to produce a desired acid, according to certain embodiments. Fig. 14B is a schematic diagram showing a dihalide reacting with water to produce a desired acid, and oxygen as a by-product, according to certain embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Detailed Description A device for chemical reactions involving an acid and / or a base, and related systems and methods are generally described. In some embodiments, the method includes generating a base in the vicinity of a first electrode (e.g., a cathode) and an acid in the vicinity of a second electrode (e.g., an anode) electrochemically connected to the first electrode. In certain embodiments, the method includes collecting the acid and / or base. In some examples, the method includes storing the acid and / or base. In some embodiments, the method includes reacting the acid and / or base in a chemical dissolution (e.g., reacting the acid with a metal carbonate, such as CaCO3, to generate a metal ion, such as calcium ion, and / or carbonate ion). In certain embodiments, the method includes reacting the acid and / or base in a precipitation reaction (e.g., reacting the base with a metal ion, such as calcium ion, to generate a metal hydroxide, such as Ca(OH)2). In some embodiments, the metal hydroxide may be used in a cement manufacturing process.

[0046] In some cases, the production of acid near the second electrode and / or the production of base near the first electrode produces gas (e.g., CO2, H2, and / or O2). In certain cases, one or more gases can be collected, sold, used in downstream processes, and / or fed back to the system. In some cases, the production of acid near the second electrode and / or the production of base near the first electrode produces a reduced amount of gas, no gas, and / or no net amount of gas, since any gas produced is used by the system (e.g., increasing the pH gradient between the electrodes). In certain embodiments, for example, during periods of low electricity costs, the acid produced near the second electrode and / or the base produced near the first electrode can be used to produce hydrogen gas and / or oxygen gas, for example, during periods of high electricity costs.

[0047] Reactors including a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient), as well as related systems and methods, are also described. In some embodiments, an electrochemical reactor includes a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In certain embodiments, a precipitate is formed using a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In some embodiments, a chemical compound (e.g., a metal salt) dissolves in a first region (e.g., an acidic region) of the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient), and a precipitate including one or more elements (e.g., metals) from the chemical compound (e.g., a metal salt) forms in a second region (e.g., an alkaline region) of the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient).

[0048] Some embodiments relate to compositions, methods and reactor designs that use electrolytic reactions to generate a chemical composition gradient between the positive and negative electrodes of an electrochemical cell. In some embodiments, the composition gradient created by said electrolysis is then used to perform a desired chemical reaction by providing reactants to a chemical environment near one electrode and using the chemical gradient created by electrolysis to generate products from said reactants as they diffuse to the other electrode. In some embodiments, the desired chemical reaction is performed by collecting solutions or suspensions of various compositions generated by electrolysis and using said solutions or suspensions to generate products from said reactants in a part of the reactor or in a separate device. In one embodiment, such reactors are directed to the generation of decomposed inorganic or metal salts by electrochemical and chemical means. In one embodiment, the use of such reactors instead of traditional thermal firings, which include heating inorganic or metal salts to decompose them, reduces or avoids the use of fossil fuels for the generation of thermal energy and the associated generation of gases that are greenhouse gases or air pollutants. In some embodiments, the inorganic or metal salt comprises a metal carbonate and the greenhouse gas produced is, at least in part, carbon dioxide. In another embodiment, the electrolysis-driven chemical reactor is powered by electricity from a renewable source, such as photovoltaic or wind energy, thereby reducing the use of greenhouse gas producing energy sources in carrying out the calcination or decomposition reaction.

[0049] Some embodiments relate to a method for producing cement, such as Portland cement. Concrete is currently the most widely used man-made material worldwide. Cement production is also the second largest industrial emitter of CO2 worldwide, accounting for about 8% of total CO2 emissions. Traditional methods of industrial production of cement include calcining CaCO3 by thermal means. In the current production of cement, about 60% of the CO2 emissions are due to the calcination of CaCO3, and about 40% of the CO2 emissions are due to the combustion of fossil fuels to carry out the calcination and sintering process. Thus, there is a great need for a cement production process with lower CO2 emissions. Some embodiments relate to a cement production process in which thermal calcination is replaced by an electrochemical process described herein, which generates less CO2 per amount of cement produced than current manufacturing methods.

[0050] A cement production system including an electrochemical reactor and associated methods is also described. Certain embodiments relate to a system of the invention for producing cement comprising an electrochemical reactor and a kiln. In certain embodiments, the electrochemical reactor is configured to receive CaCO. In some embodiments, the electrochemical reactor comprises a first outlet configured to remove Ca(OH) and / or lime (CaO). In certain cases, the electrochemical reactor comprises a second outlet configured to remove CO, O, and / or H gas. According to certain embodiments, the kiln is configured to heat the Ca(OH) and / or lime (and / or reaction products thereof) as part of a cement manufacturing process.

[0051] In some embodiments, the system is at least partially (e.g., at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, or 100%) powered by renewable electricity (e.g., solar and / or wind energy). In certain cases, the system has a lower net carbon footprint (e.g., at least 10% less, at least 25% less, at least 50% less, at least 75% less, or at least 90% less) than a substantially similar system that uses traditional thermal firing instead of an electrochemical reactor. In some examples, the system has a net zero carbon footprint.

[0052] Certain embodiments relate to the method of the invention, in which Ca(OH)2 and / or lime (CaO) are produced in an electrochemical reactor. In some embodiments, the Ca(OH)2 and / or lime from the electrochemical reactor are then transported to a kiln, which heats the Ca(OH)2 and / or lime (and / or their reaction products) as part of the cement manufacturing process. In some embodiments, the electrochemical reactor also produces CO2, O2 and / or H2 gas. According to certain embodiments, CO2 is sequestered, used in liquid fuels, used in oxyfuels, used in enhanced oil recovery, used to produce dry ice, and / or used as an ingredient in beverages. In some cases, O2 can be sequestered, used in oxyfuels, used for CCS applications, and / or used in enhanced oil recovery. In certain examples, H2 can be sequestered and / or used as a fuel (e.g., in fuel cells and / or for heating systems). In some embodiments, at least a portion (e.g., at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, or all) of the CO2, O2, and / or H2 removed from the system is fed to a kiln.

[0053] As noted above, certain embodiments relate to systems, non-limiting examples of which are shown in Figures 1A-3B.

[0054] In some embodiments, the system comprises a first electrode. In some embodiments, the first electrode comprises a cathode. For example, with reference to FIG. 1A, in some embodiments, the system 100 comprises a first electrode 104 (e.g., a cathode). Similarly, with reference to FIG. 2A, in some embodiments, the system 200 comprises a first electrode 104 (e.g., a cathode). In certain embodiments, the first electrode is selected to be a stable electronic conductor under relatively alkaline conditions (e.g., in the alkaline range and / or bases described herein).

[0055] In certain embodiments, the first electrode comprises a metal electrode (such as platinum, gold, nickel, iridium, copper, iron, steel, stainless steel, manganese, and / or zinc), carbon (such as graphite or disordered carbon), or a metal carbide (such as silicon carbide, titanium carbide, and / or tungsten carbide). In certain embodiments, the first electrode comprises a metal alloy (e.g., nickel-chromium-iron alloy, nickel-molybdenum-cadmium alloy), a metal oxide (e.g., iridium oxide, nickel iron cobalt oxide, nickel cobalt oxide, lithium cobalt oxide, lanthanum strontium cobalt oxide, barium strontium iron oxide, manganese molybdenum oxide, ruthenium dioxide, iridium ruthenium tantalum oxide), a metal-organic framework, or a metal sulfide (e.g., molybdenum sulfide). In certain embodiments, the electrocatalyst or electrode material is dispersed and coated on the conductive support surface.

[0056] In some embodiments, the system includes a second electrode. In some embodiments, the second electrode includes an anode. For example, referring back to FIG. 1A, in some embodiments, the system 100 includes a second electrode 105 (e.g., an anode). Similarly, referring back to FIG. 2A, in some embodiments, the system 200 includes a second electrode 105 (e.g., an anode). In some embodiments, the second electrode is electrochemically connected to the first electrode. That is, the electrodes can be configured to be capable of participating in an electrochemical process. Electrochemical coupling can be achieved, for example, by exposing the first and second electrodes to an electrolyte that facilitates the transport of ions between the two electrodes. Referring back to FIG. 1A, in some embodiments, the first electrode 104 is electrochemically connected to the second electrode 105. Similarly, referring back to FIG. 2A, in some embodiments, the first electrode 104 is electrochemically connected to the second electrode 105.

[0057] In certain embodiments, the second electrode is selected to be an electronic conductor that is stable under relatively acidic conditions (e.g., in the acidic range and / or acids described herein). In certain embodiments, the second electrode comprises a metallic electrode (such as platinum, palladium, lead, and / or tin) or a metal oxide (such as a transition metal oxide).

[0058] In certain embodiments, the first electrode and / or the second electrode include a catalyst. In some embodiments, the cathode catalyst is selected to be stable under alkaline conditions. The cathode catalyst may include nickel, iron, transition metal sulfides (such as molybdenum sulfide), and / or transition metal oxides (such as MnO2, Mn2O3, Mn3O4, nickel oxide, nickel hydroxide, iron oxide, iron hydroxide, cobalt oxide, etc.), complex transition metal spinel oxides (such as MnCo2O4, CoMn2O4, MnFe2O4, ZnCoMnO4, etc.) in some embodiments. In some embodiments, the anode catalyst is selected to be stable under acidic conditions. In some embodiments, the anode catalyst includes platinum, iridium, or oxides thereof.

[0059] In some embodiments, the system includes a reactor (e.g., an electrochemical reactor). For example, referring to FIG. 1A, in some embodiments, the system 100 includes a reactor. Similarly, referring to FIG. 2A, in certain cases, the system 200 includes a reactor. In some embodiments, the reactor includes a first electrode and a second electrode. For example, in some embodiments, the first electrode is electrochemically connected to the second electrode in the reactor. For example, referring to FIG. 1A, in some embodiments, the first electrode 104 is electrochemically connected to the second electrode 105 in the reactor. Similarly, referring to FIG. 2A, in certain cases, the first electrode 104 is electrochemically connected to the second electrode 105 in the reactor.

[0060] Certain aspects relate to methods that may be understood with respect to Figures 1A-3B. In some embodiments, the methods include operating a reactor (e.g., any reactor described herein). In certain cases, operating the reactor includes applying an electric current to electrodes of the reactor. In some embodiments, operating the reactor results in at least one chemical reaction occurring within the reactor.

[0061] In certain embodiments, the method includes operating the reactor in a first mode. In some embodiments, the first mode includes generating a base in the vicinity of a first electrode (e.g., the base is generated as a result of an electrochemical reaction at the first electrode). For example, with reference to FIG. 1A, in some embodiments, the first mode includes generating a base in the vicinity of the first electrode 104. Similarly, with reference to FIG. 2A, in certain cases, the first mode includes generating a base in the vicinity of the first electrode 104.

[0062] In certain embodiments, the first electrode (e.g., in a first mode) is configured to generate a basic product (e.g., any of the bases described herein). In some embodiments, the basic product is generated as a result of an electrochemical reaction at the first electrode. For example, with reference to FIG. 1A, in some embodiments, the first electrode 104 is configured to generate a base. Similarly, with reference to FIG. 2A, in some examples, the first electrode 104 is configured to generate a base.

[0063] The base can have any of various suitable concentrations.In some embodiments, the base has a concentration of greater than or equal to 0.000001M, greater than or equal to 0.00001M, greater than or equal to 0.0001M, greater than or equal to 0.001M, greater than or equal to 0.01M, greater than or equal to 0.1M, greater than or equal to 0.5M, greater than or equal to 1M, greater than or equal to 3M, greater than or equal to 5M, greater than or equal to 7M, greater than or equal to 10M, greater than or equal to 15M, or greater than or equal to 20M.In certain embodiments, the base has a concentration of less than or equal to 25M, less than or equal to 20M, less than or equal to 15M, less than or equal to 10M, less than or equal to 7M, less than or equal to 5M, or less than or equal to 3M. Combinations of these ranges are also contemplated (eg, greater than or equal to 0.1M and less than or equal to 25M, or greater than or equal to 0.1M and less than or equal to 10M).

[0064] According to some embodiments, production of base by the first electrode results in an alkaline region (e.g., any of the alkaline regions described herein) in the vicinity of the first electrode (e.g., within the half of the compartment of the reactor closest to the first electrode). For example, in some instances, the fluid adjacent the first electrode (e.g., the alkaline region) has a higher pH than the liquid further away from the first electrode. As an example, with reference to FIG. 2A, in some instances, the system includes an alkaline region 106 in the vicinity of the first electrode 104. Similarly, with reference to FIG. 1A, in certain instances, the system includes an alkaline region in the vicinity of the first electrode 104.

[0065] In some embodiments, the pH near (e.g., adjacent) the first electrode is greater than or equal to 8, greater than or equal to 9, greater than or equal to 10, greater than or equal to 11, greater than or equal to 12, or greater than or equal to 13. According to some embodiments, the pH near the first electrode is less than or equal to 14, less than or equal to 13, less than or equal to 12, less than or equal to 11, or less than or equal to 10. Combinations of these ranges are also contemplated (e.g., greater than or equal to 8 and less than or equal to 14).

[0066] In some embodiments, the second electrode is configured to generate an acidic product (e.g., any of the acids described herein). In certain embodiments, the acidic product is generated as a result of an electrochemical reaction at the second electrode. For example, with reference to FIG. 1A, in some embodiments, the second electrode 105 is configured to generate an acid. Similarly, with reference to FIG. 2A, in certain cases, the second electrode 105 is configured to generate an acid. In some embodiments, the first mode of the reactor includes generating an acid in the vicinity of the second electrode (e.g., the acid is generated as a result of an electrochemical reaction at the second electrode). For example, with reference to FIG. 1A, in some embodiments, the first mode includes generating an acid in the vicinity of the second electrode 105. Similarly, with reference to FIG. 2A, in certain embodiments, the first mode includes generating an acid in the vicinity of the second electrode 105.

[0067] The acid can have any of various suitable concentrations. In some embodiments, the acid has a concentration of greater than or equal to 0.000001M, greater than or equal to 0.00001M, greater than or equal to 0.0001M, greater than or equal to 0.001M, greater than or equal to 0.01M, greater than or equal to 0.1M, greater than or equal to 0.5M, greater than or equal to 1M, greater than or equal to 3M, greater than or equal to 5M, greater than or equal to 7M, or greater than or equal to 10M. In certain embodiments, the acid has a concentration of less than or equal to 12M, less than or equal to 10M, less than or equal to 7M, less than or equal to 5M, less than or equal to 3M, or less than or equal to 1M. Combinations of these ranges are also contemplated (eg, greater than or equal to 0.000001M and less than or equal to 12M, or greater than or equal to 0.1M and less than or equal to 10M).

[0068] According to some embodiments, production of acid by the second electrode results in an acidic region (e.g., any acidic region described herein) in the vicinity of the second electrode (e.g., within the half of the compartment of the reactor closest to the second electrode). For example, in some instances, the fluid adjacent to the second electrode (e.g., the acidic region) has a lower pH than the liquid further away from the second electrode. As an example, with reference to FIG. 2A, in some instances, the system includes an acidic region 107 in the vicinity of the second electrode 105. Similarly, with reference to FIG. 1A, in certain instances, the system includes an acidic region 107 in the vicinity of the second electrode 105.

[0069] According to certain embodiments, the pH near (e.g., adjacent to) the second electrode has a pH lower than or equal to 6, lower than or equal to 5, lower than or equal to 4, lower than or equal to 3, lower than or equal to 2, or lower than or equal to 1. In some embodiments, the pH near the second electrode has a pH higher than or equal to 0, higher than or equal to 1, higher than or equal to 2, higher than or equal to 3, higher than or equal to 4, or higher than or equal to 5. Combinations of these ranges are also contemplated (e.g., higher than or equal to 0 and lower than or equal to 6).

[0070] In certain embodiments, the first electrode (e.g., cathode) is configured to generate hydrogen gas such that hydrogen gas can be generated in the vicinity of the first electrode (e.g., hydrogen gas is generated as a result of an electrochemical reaction at the first electrode). For example, with reference to FIG. 2A, in some embodiments, the first electrode 104 is configured to generate hydrogen gas 108. Similarly, with reference to FIG. 1A, in certain examples, the first electrode 104 is configured to generate hydrogen gas. In some examples, operating the reactor in the first mode includes generating hydrogen gas (e.g., hydrogen gas and a base) in the vicinity of the first electrode (e.g., hydrogen gas is generated as a result of an electrochemical reaction at the first electrode). In some examples, hydrogen gas and / or a base are generated in the vicinity of the first electrode by reduction of water in the vicinity of the first electrode.

[0071] In certain embodiments, the second electrode (e.g., the anode) is configured to generate oxygen such that oxygen gas can be generated in the vicinity of the second electrode (e.g., oxygen gas is generated as a result of an electrochemical reaction at the second electrode). For example, with reference to FIG. 2A, in some embodiments, the second electrode 105 is configured to generate oxygen gas 109. Similarly, with reference to FIG. 1A, in certain embodiments, the second electrode 105 is configured to generate oxygen gas. In certain cases, operating the reactor in the first mode includes generating oxygen gas (e.g., oxygen gas and acid) in the vicinity of the second electrode (e.g., oxygen gas is generated as a result of an electrochemical reaction at the second electrode). In some examples, the oxygen gas and / or acid are generated in the vicinity of the second electrode by oxidation of water in the vicinity of the second electrode.

[0072] In some embodiments, the system is configured to allow oxygen gas to diffuse and / or be transported to a location near the first electrode (e.g., from a location near the second electrode). For example, in some cases, the system is configured to allow oxygen gas to diffuse and / or be transported to a fluid near the first electrode such that oxygen gas from a fluid near the second electrode can participate in the electrochemical reaction at the first electrode after oxygen gas is produced as a result of the electrochemical reaction at the second electrode. For example, with reference to FIG. 2A, in some embodiments, the system 200 is configured to allow oxygen gas 109 to diffuse and / or be transported from the second electrode 105 to the first electrode 104. Similarly, with reference to FIG. 1A, in certain embodiments, the system 100 is configured to allow oxygen gas to diffuse and / or be transported from the second electrode 105 to the first electrode 104.

[0073] According to certain embodiments, the system is configured to allow oxygen gas to be reduced in the vicinity of the first electrode (e.g., oxygen gas is reduced as a result of an electrochemical reaction at the first electrode). For example, referring to FIG. 2A, in certain embodiments, the system 200 is configured to allow oxygen gas 109 to be reduced in the vicinity of the first electrode 104. Similarly, referring to FIG. 1A, in some examples, the system 100 is configured to allow oxygen gas to be reduced in the vicinity of the first electrode 104. In some embodiments, reducing oxygen gas in the vicinity of the first electrode includes generating a base. In certain embodiments, generating a base is advantageous because it increases the total amount of base generated at the first electrode.

[0074] In some embodiments, the system is configured to allow hydrogen gas to diffuse and / or be transported to a location near the second electrode (e.g., from a location near the first electrode). For example, in some cases, the system is configured to allow hydrogen gas to diffuse and / or be transported to a fluid near the second electrode, so that hydrogen gas from the fluid near the first electrode can participate in the electrochemical reaction at the second electrode after hydrogen gas is generated as a result of the electrochemical reaction at the first electrode. For example, with reference to FIG. 2A, in certain cases, the system 200 is configured to allow hydrogen gas 108 to diffuse and / or be transported from the first electrode 104 to the second electrode 105. Similarly, with reference to FIG. 1A, in some cases, the system 100 is configured to allow hydrogen gas to diffuse and / or be transported from the first electrode 104 to the second electrode 105.

[0075] According to certain embodiments, the system is configured to allow hydrogen gas to be oxidized near the second electrode (e.g., hydrogen gas is oxidized at the second electrode as a result of an electrochemical reaction). For example, with reference to FIG. 2A, in some embodiments, system 200 is configured to allow hydrogen gas 108 to be oxidized near the second electrode 105. Similarly, with reference to FIG. 1A, in certain embodiments, system 100 is configured to allow hydrogen gas to be oxidized near the second electrode. In some embodiments, oxidizing hydrogen gas near the second electrode includes generating an acid. In certain embodiments, generating an acid is advantageous because it increases the total amount of acid generated at the second electrode.

[0076] In some embodiments, the system includes a separator. For example, referring to FIG. 1C, in some embodiments, the system 100 includes a separator 124. Similarly, referring to FIG. 2B, in certain embodiments, the system 200 includes a separator 124. In certain embodiments, the separator is configured to allow oxygen gas produced at the second electrode to diffuse to the first electrode and / or allow hydrogen gas produced at the first electrode to diffuse to the second electrode. For example, in some embodiments, the separator is permeable to oxygen gas and / or hydrogen gas. For example, referring to FIG. 1C, in some embodiments, the separator 124 is configured to allow oxygen gas produced at the second electrode to diffuse to the first electrode and / or allow hydrogen gas produced at the first electrode to diffuse to the second electrode. Similarly, with reference to FIG. 2B, in certain embodiments, separator 124 is configured to allow oxygen gas produced at the second electrode to diffuse to the first electrode and / or to allow hydrogen gas produced at the first electrode to diffuse to the second electrode.

[0077] There may be many suitable ways to transport hydrogen gas and / or oxygen gas from one electrode to the other. For example, in some embodiments, hydrogen gas and / or oxygen gas may be transported using a syringe (e.g., if the reactor has an inlet for a syringe near one of the electrodes and an outlet for a syringe near the other electrode, the gas may be transported from one electrode to the other electrode by a syringe). In certain embodiments, hydrogen gas and / or oxygen gas may be transported through a conduit (e.g., a pipe, a channel, a needle, or a tube). In some cases, hydrogen gas and / or oxygen gas may be transported directly from one electrode to another electrode, or hydrogen gas and / or oxygen gas may be stored after removal from the reactor until it is added back to the reactor. In some embodiments, hydrogen gas and / or oxygen gas is transported continuously or in batches. In certain embodiments, hydrogen gas and / or oxygen gas is transported automatically or manually.

[0078] In some embodiments, the hydrogen gas produced by hydrolysis can be electrochemically oxidized using a hydrogen oxidation reaction (HOR), in which one hydrogen molecule reacts to form two protons and two electrons. In other embodiments, the oxygen gas produced by hydrolysis can be electrochemically reduced in an oxygen reduction reaction (ORR), in which one oxygen molecule reacts with two water molecules and four electrons to form four hydroxyl ions. In some embodiments, the HOR reaction is used to lower the pH or increase the proton concentration of an acidic solution produced by the reactor. In some embodiments, the ORR reaction is used to increase the pH or increase the hydroxyl concentration of a basic solution produced by the reactor. The HOR and ORR reactions described herein can be performed using separate electrodes, in some cases, derived from those used in the electrolysis reaction of the reactor. In certain embodiments, these electrodes can be placed in the electrolysis reaction, for example, as combustion electrodes, where the combustion reaction of hydrogen and oxygen produces water that remains in the reactor. The electrodes used for combustion, or HOR or ORR, in some examples, may also be placed in separate vessels or reactors into which hydrogen gas or oxygen gas, respectively, are fed. In some embodiments, hydrogen produced at the cathode of the electrolysis reactor is fed to an HOR electrode connected to the anode side of the reactor, where HOR is performed and the protons produced thereby improve the acid concentration (lower the pH) of the acidic solution produced by the reactor. In certain embodiments, oxygen produced at the anode of the electrolysis reactor is fed to an ORR electrode connected to the cathode side of the reactor, where ORR is performed and the hydroxyl ions produced thereby improve the hydroxyl concentration (higher the pH) of the alkaline solution produced by the reactor. In some examples, the HOR reaction is preferentially performed over the ORR reaction, resulting in lower hydrogen release, compared to oxygen, which is less reactive to the external environment.Electrodes used in hydrogen-oxygen combustion or HOR or ORR may, in some cases, contain compounds that function as electrocatalysts. Hydrogen-oxygen combustion catalysts are described, for example, in "Catalytic Combustion of Hydrogen - Its Role in Hydrogen Utilization," International Journal of Hydrogen Energy, Vol. 6, No. 6, pp. 601-608, 1981, by M Haruta and H Sano, which is incorporated by reference. Examples of electrocatalysts for HOR and ORR include platinum group metals such as Pt, Pd, Ru, Rh, Os, and Ir, non-platinum group metals such as Mo, Fe, Ti, W, Cr, Co, Cu, Ag, Au, and Re, used individually or as alloys or mixtures, and high surface area nickel-aluminum alloys known as Raney nickel, optionally coated or doped with other catalysts. Examples of electrocatalysts selective for the ORR include metallic iron, iron oxide, iron sulfide and hydroxide, silver alloys, silver oxide and silver nitrate, and various forms of carbon, including carbon paper, carbon felt, graphite, carbon black and nanoscale carbon.

[0079] In certain embodiments described herein, the gaseous by-products (e.g., CO2, H2 and / or O2) produced by electrolysis may be valuable and may be sold for use in other applications and processes, including combustion in fuel cells or gas turbines or internal combustion engines for the purpose of generating energy and power, including electricity. However, in some instances, it may be desirable to reduce or eliminate the production of such gases. Thus, in some embodiments, one or more of the gases produced by the reactor are recombined. As used herein, recombining refers to a chemical or electrochemical reaction that consumes one or more of the produced gases.

[0080] In some embodiments, the hydrogen and acid produced by hydrolysis are recombined to form water using hydrogen-oxygen combustion. For example, referring to FIG. 2A, in some embodiments, the hydrogen gas 108 produced by the first electrode 104 can be recombined with oxygen gas 109 to form water, as shown in FIG. 6A. Similarly, referring to FIG. 1A, in certain embodiments, the hydrogen gas produced by the first electrode 104 can be recombined with oxygen gas to form water. According to certain embodiments, the hydrogen-oxygen recombination may be performed inside or outside the reactor, in some cases using electrode materials and designs and, if necessary, catalysts known to those skilled in the art. In certain embodiments, the method does not produce a net hydrogen gas (or produces a net amount of hydrogen gas that is less than 5% (e.g., less than 2%, or less than 1%) of the current supplied to the reactor). For example, in some embodiments, the method does not release any hydrogen gas (or the amount of hydrogen gas released is less than 5% (e.g., less than 2%, or less than 1%) of the current supplied to the reactor) because the hydrogen gas produced is recombined with oxygen to form water. Similarly, in some cases, the method does not produce a net amount of oxygen gas (or the amount of oxygen gas released is less than 5% (e.g., less than 2%, or less than 1%) of the current supplied to the reactor). For example, in certain instances, the method does not release any oxygen gas (or the amount of oxygen gas released is less than 5% (e.g., less than 2%, or less than 1%) of the current supplied to the reactor) because the oxygen gas produced is recombined with hydrogen to form water.

[0081] In some embodiments, hydrolysis is carried out under conditions that produce a basic pH near the first electrode (e.g., cathode) and an acidic pH near the second electrode (e.g., anode) without liberating hydrogen or oxygen gas (or liberating less than 5% (e.g., less than 2% or less than 1%), respectively. For example, in some embodiments, O2 is converted from the second electrode (e.g., anode) where acid and O2 are produced, and base is produced and O2 is reduced to OH. -Form (1 / 2O2+H2O+2e - →2OH - ) to a first electrode (e.g., a cathode) (e.g., through the electrolyte 235 in FIG. 2A and / or through the air above the electrolyte). In certain embodiments, this reaction can occur at a pH > 7 and an electrode potential of less than 0.8 V versus the standard hydrogen electrode. Similarly, in some cases, H2 can diffuse from a first electrode (e.g., a cathode) where a base is produced, an acid is produced, and H2 is oxidized to H + Form (H2 → 2H + +2e - ) can diffuse to a second electrode (e.g., an anode). In certain instances, this can occur when the pH is <7 and the electrode potential is higher than -0.41 V versus the standard hydrogen electrode. In other electrolyzers, such as alkaline electrolyzers, this reaction is impeded by a separator that prevents gas crossing between the two electrodes. However, in some embodiments disclosed herein, the reactor includes a separator that allows and / or facilitates the crossing of H2 and / or O2 so that they can be consumed to increase the pH gradient.

[0082] In some embodiments, acidic solutions (pH less than 7) are produced from electrolytes of neutral pH at electrode potentials greater than 0.8 V vs. the standard hydrogen electrode. For example, in certain embodiments, the minimum electrode potential for making an acidic solution of pH 0 will be 1.23 V vs. the standard hydrogen electrode. In some cases, basic solutions (pH greater than 7) are produced from electrolytes of neutral pH at electrode potentials less than -0.4 V vs. the standard hydrogen electrode. For example, the maximum electrode potential for making an alkaline solution of pH 14 will be -0.83 V vs. the standard hydrogen electrode.

[0083] The Nernst potential at the second electrode (e.g., the Nernst potential in the fluid closest to the second electrode) can be any of a variety of suitable values. In some embodiments, the Nernst potential at the second electrode (e.g., the anode) is greater than or equal to -0.4V, greater than or equal to -0.2V, greater than or equal to 0V, greater than or equal to 0.5V, greater than or equal to 0.8V, greater than or equal to 0.9V, greater than or equal to 1V, greater than or equal to 1.1V, greater than or equal to 1.2V, greater than or equal to 1.4V, or greater than or equal to 1.6V relative to a standard hydrogen electrode. In certain embodiments, the Nernst potential at the second electrode is less than or equal to 2 V, less than or equal to 1.7 V, less than or equal to 1.5 V, less than or equal to 1.4 V, less than or equal to 1.3 V, less than or equal to 1.2 V, less than or equal to 1.1 V, less than or equal to 1 V, less than or equal to 0.9 V, less than or equal to 0.8 V, less than or equal to 0.5 V, less than or equal to 0 V, or less than or equal to -0.2 V, relative to a standard hydrogen electrode. Combinations of these ranges are also contemplated (e.g., greater than or equal to 0.8 V, less than or equal to 2 V, greater than or equal to 1.2 V, less than or equal to 2 V, greater than or equal to -0.4 V, less than or equal to 0.5 V, or greater than or equal to 0 V, less than or equal to 0.5 V).

[0084] In certain embodiments, the suitable Nernst potential at the second electrode depends on the type of reaction at the electrode.For example, in some cases, the Nernst potential at the second electrode when hydrogen gas is oxidized to acid is greater than or equal to -0.4V (e.g., greater than or equal to -0.4V, less than or equal to 0.5V, or greater than or equal to 0V, less than or equal to 0.5V) with respect to the standard hydrogen electrode.As another example, in certain cases, the Nernst potential at the second electrode when water is oxidized to acid and oxygen gas is greater than or equal to 0.8V (e.g., greater than or equal to 0.8V, less than or equal to 2V, or greater than or equal to 1.2V, less than or equal to 2V) with respect to the standard hydrogen electrode.

[0085] The Nernst potential at the first electrode (e.g., the Nernst potential in the fluid closest to the first electrode) can be any of a variety of suitable values. In certain embodiments, the Nernst potential at the first electrode (e.g., the cathode) is less than or equal to 0.8 V, less than or equal to 0.6 V, less than or equal to 0.4 V, less than or equal to 0 V, less than or equal to -0.4 V, less than or equal to -0.5 V, less than or equal to -0.6 V, less than or equal to -0.7 V, less than or equal to -0.8 V, less than or equal to -0.9 V, less than or equal to -1 V, less than or equal to -1.2 V, or less than or equal to -1.4 V, relative to a standard hydrogen electrode. In some embodiments, the Nernst potential at the first electrode is greater than or equal to -2 V, greater than or equal to -1.7 V, greater than or equal to -1.5 V, greater than or equal to -1.2 V, greater than or equal to -1 V, greater than or equal to -0.9 V, greater than or equal to -0.8 V, greater than or equal to -0.7 V, greater than or equal to -0.6 V, greater than or equal to -0.5 V, greater than or equal to -0.4 V, greater than or equal to 0 V, greater than or equal to 0.4 V, or greater than or equal to 0.6 V, with combinations of these ranges also being contemplated (e.g., greater than or equal to -1.5 V, less than or equal to -0.4 V, greater than or equal to -1.5 V, less than or equal to -0.8 V, greater than or equal to -0.4 V, less than or equal to 0.8 V, or greater than or equal to -0.4 V, less than or equal to 0.4 V).

[0086] In certain embodiments, the suitable Nernst potential at the first electrode depends on the type of reaction at the electrode.For example, in some cases, the Nernst potential at the first electrode when oxygen gas is reduced to base is less than or equal to 0.8V (e.g., less than or equal to 0.8V, greater than or equal to -0.4V, or less than or equal to 0.4V, greater than or equal to -0.4V) with respect to standard hydrogen electrode.As another example, in certain cases, the Nernst potential at the first electrode when water is reduced to base and hydrogen gas is less than or equal to -0.4V (e.g., less than or equal to -0.4V, greater than or equal to -1.5V, or less than or equal to -0.8V, greater than or equal to -1.5V) with respect to standard hydrogen electrode.

[0087] In certain embodiments, the cell voltage (e.g., the voltage applied to the cell, e.g., during acid and / or base production) is greater than or equal to 0 V, greater than or equal to 0.5 V, greater than or equal to 1 V, greater than or equal to 1.23 V, greater than or equal to 1.5 V, greater than or equal to 2 V, greater than or equal to 2.06 V, or greater than or equal to 2.5 V, versus a standard hydrogen electrode. In some embodiments, the cell voltage is less than or equal to 5 V, less than or equal to 4 V, less than or equal to 3 V, less than or equal to 2.5 V, less than or equal to 2.25 V, less than or equal to 2 V, less than or equal to 1.5 V, less than or equal to 1 V, or less than or equal to 0.5 V, versus a standard hydrogen electrode. Combinations of these ranges are also contemplated (e.g., 0-5 V or 0-2.5 V).

[0088] In some embodiments, the system comprises a reactor system for producing concentrated acid and base. According to some embodiments, the system comprises a first reactor (e.g., any reactor described herein). For example, referring to FIG. 3A, in some embodiments, the system 300 comprises a first reactor 320. According to some embodiments, the system comprises a second reactor (e.g., any reactor described herein). For example, referring to FIG. 3A, in some embodiments, the system 300 comprises a second reactor 301. In certain cases, the first reactor and the second reactor are fluidly connected. For example, referring to FIG. 3A, in some embodiments, the first reactor 320 is fluidly connected to the second reactor 301 via a conduit 330. For example, in some cases, a fluid (e.g., liquid or gas) produced in the first reactor can diffuse and / or be transported to the second reactor. As a non-limiting example, in certain embodiments, the method includes diffusing and / or transporting hydrogen gas and / or a dihalide from a first reactor to a second reactor.

[0089] In some embodiments, the first reactor comprises an electrochemical reactor. In certain cases, the first reactor comprises a first electrode (e.g., any first electrode described herein). For example, referring to FIG. 3B, in some cases, the first reactor 320 comprises a first electrode 104. In some cases, the first reactor comprises a second electrode (e.g., any second electrode described herein). For example, referring to FIG. 3B, in some cases, the first reactor 320 comprises a second electrode 105. In some embodiments, the second electrode is electrochemically connected to the first electrode (e.g., the electrodes are configured to allow current to flow from one electrode to the other). That is, the electrodes can be configured to be capable of participating in an electrochemical process. Electrochemical coupling can be achieved, for example, by exposing the first and second electrodes to an electrolyte that facilitates the transport of ions between the two electrodes. For example, with reference to FIG. 3A, in some embodiments, the first electrode 104 is electrochemically connected to the second electrode 105 .

[0090] In certain examples, the second reactor comprises a fuel cell (e.g., a H2 / Cl2 fuel cell). In some embodiments, the method includes generating an acid in the second reactor. For example, in certain cases, the second reactor 301 in FIG. 3A is configured to generate an acid (e.g., any acid described herein).

[0091] In certain embodiments, the method includes generating a base (e.g., any base described herein), a dihalide, and / or hydrogen gas in the first reactor. For example, with reference to FIG. 3A, in some cases, the first reactor 320 is configured to generate a base, a dihalide, and / or hydrogen gas. In some cases, the dihalide is generated near the second electrode of the first reactor (e.g., the dihalide is generated as a result of an electrochemical reaction at the second electrode of the first reactor). For example, with reference to FIG. 3B, in certain cases, the dihalide is generated near the second electrode 105 of the first reactor 320. In some embodiments, the base and / or hydrogen gas is generated near the first electrode (e.g., the base and / or hydrogen gas is generated as a result of an electrochemical reaction at the first electrode). For example, with reference to FIG. 3B, in certain cases, the base is generated near the first electrode 104.

[0092] The Nernst potential at the second electrode of the first reactor (e.g., the Nernst potential at the fluid closest to the second electrode) can be any of a variety of suitable values. In some embodiments, the Nernst potential at the second electrode (e.g., the anode) of the first reactor is greater than or equal to 1.3 V, greater than or equal to 1.5 V, greater than or equal to 1.7 V, greater than or equal to 1.9 V, greater than or equal to 2.1 V, or greater than or equal to 2.3 V, relative to the standard hydrogen electrode. In certain embodiments, the Nernst potential at the second electrode of the first reactor is less than or equal to 2.5 V, less than or equal to 2.3 V, less than or equal to 2.1 V, less than or equal to 1.9 V, less than or equal to 1.7 V, or less than or equal to 1.5 V, relative to the standard hydrogen electrode. Combinations of these ranges are also contemplated (e.g., greater than or equal to 1.3 V, less than or equal to 2.5 V).

[0093] In certain embodiments, the suitable Nernst potential at the second electrode of the first reactor depends on the type of reaction at the electrode. For example, in some cases, when a dihalide is produced (e.g., chloride ions are oxidized to form Cl2), the Nernst potential at the second electrode is greater than or equal to 1.3 V (e.g., greater than or equal to 1.3 V and less than or equal to 2.5 V) versus a standard hydrogen electrode.

[0094] In some embodiments, Cl2 is generated from Cl− at a Nernst potential greater than 1.36 V versus a standard hydrogen electrode (e.g., greater than or equal to 1.4 V, greater than or equal to 1.5 V, greater than or equal to 1.7 V, or greater than or equal to 2 V versus a standard hydrogen electrode; less than or equal to 5 V, less than or equal to 3 V, less than or equal to 2 V, or less than or equal to 1.5 V; combinations are also contemplated).

[0095] In certain embodiments, Br2 is generated from Br− at a Nernst potential greater than 1.06 V versus a standard hydrogen electrode (e.g., greater than or equal to 1.1 V, greater than or equal to 1.2 V, greater than or equal to 1.3 V, greater than or equal to 1.5 V, or greater than or equal to 1.8 V; less than or equal to 4 V, less than or equal to 3 V, less than or equal to 2 V, or less than or equal to 1.5 V; combinations are contemplated).

[0096] In some cases, I2 is generated from I− at a Nernst potential greater than 0.54 V versus a standard hydrogen electrode (e.g., greater than or equal to 0.6 V, greater than or equal to 0.7 V, greater than or equal to 0.8 V, greater than or equal to 0.9 V, greater than or equal to 1 V, or greater than or equal to 1.2 V; less than or equal to 3 V, less than or equal to 2 V, less than or equal to 1.5 V, less than or equal to 1.3 V, or less than or equal to 1 V; combinations are also contemplated).

[0097] The Nernst potential at the first electrode of the first reactor (e.g., the Nernst potential at the fluid closest to the first electrode) can be any of a variety of suitable values. In some embodiments, the Nernst potential at the first electrode (e.g., the cathode) of the first reactor is greater than or equal to -2V, greater than or equal to -1.8V, greater than or equal to -1.6V, greater than or equal to -1.4V, greater than or equal to -1.2V, greater than or equal to -1.0V, greater than or equal to -0.8V, greater than or equal to -0.6V, greater than or equal to -0.4V, greater than or equal to -0.2V, greater than or equal to 0V, greater than or equal to 0.2V, greater than or equal to 0.4V, or greater than or equal to 0.6V relative to a standard hydrogen electrode. In certain embodiments, the Nernst potential at the first electrode of the first reactor is less than or equal to 0.8 V, less than or equal to 0.6 V, less than or equal to 0.4 V, less than or equal to 0.2 V, less than or equal to 0 V, less than or equal to -0.2 V, less than or equal to -0.4 V, less than or equal to -0.6 V, less than or equal to -0.8 V, less than or equal to -1.0 V, less than or equal to -1.2 V, less than or equal to -1.4 V, or less than or equal to -1.6 V versus a standard hydrogen electrode. Combinations of these ranges are also contemplated (e.g., greater than or equal to -2V and less than or equal to 0.8V, greater than or equal to -1.4V and less than or equal to 0.4V, greater than or equal to -2V and less than or equal to -0.4V, or greater than or equal to -2V and less than or equal to -0.8V).

[0098] In certain embodiments, the suitable Nernst potential of the first electrode of the first reactor depends on the type of reaction at the electrode.For example, in some cases, the Nernst potential of the first electrode when oxygen is reduced to form base is less than or equal to 0.8V with respect to the standard hydrogen electrode (e.g., greater than or equal to -2V, less than or equal to 0.8V, or greater than or equal to -1.4V, less than or equal to 0.4V).As another example, in certain cases, the Nernst potential of the first electrode when water is reduced to hydrogen gas is less than or equal to -0.4V with respect to the standard hydrogen electrode (e.g., greater than or equal to -2V, less than or equal to -0.4V, or greater than or equal to -2V, less than or equal to -0.8V).

[0099] In certain embodiments, the first reactor produces a base / alkaline solution, a dihalide, and hydrogen gas from an electrolyte containing a salt of a halide. Figure 11 shows a neutral water electrolyzer-based reactor as disclosed herein, according to certain embodiments, whereby electrolysis or hydrolysis produces an acidic solution and an alkaline solution, which is then used to decarbonate the starting metal carbonate, and then the alkaline solution is used to precipitate metal hydroxides from the dissolved metal ions of the starting metal carbonate. In some embodiments, the volumetric concentrations of reactants at which such a reactor operates are determined by the value of pH generated by the electrolyzer.

[0100] An alternative reactor concept according to certain embodiments is shown in FIG. 12. According to some embodiments, this reactor is capable of producing higher concentrations of acid and base than the reactor in FIG. 11. In some embodiments, the system includes a first reactor that electrolytically oxidizes a near-neutral solution of dissolved metal salts to produce an alkaline solution, a compound rich in hydrogen and anions of the metal salts. In some embodiments, the metal salts are salts of alkali halides or salts of alkaline earth halides, and the compounds produced are dihalides. A second reactor produces an acidic solution by reacting the compounds and hydrogen with water according to certain embodiments. In some embodiments, the acidic solution produced by the second reactor and the alkaline solution produced by the first reactor are then used, respectively, to dissolve the metal carbonates releasing CO2 and precipitate the metal hydroxides. In certain embodiments, unlike the reactor in FIG. 11, a H2O solution higher than about 1 molar is used. + and O.H. - Where absolute concentrations can be difficult to reach, the reactor of FIG. 12 can reach 3 molar, 5 molar, or even higher concentrations.

[0101] In certain embodiments, the first reactor comprises a second electrode (e.g., an anode), a first electrode (e.g., a cathode), a semi-transparent membrane between the two electrodes, an inlet for the electrolyte, and an outlet for the products of electrolysis (H2, dihalides, and an alkaline solution). In some embodiments, an additional inlet in the vicinity of the first electrode introduces O2. In some cases, the electrolyte is a near-neutral aqueous solution in which metal salts dissolve. In certain cases, the aqueous solution contains anions of halides (e.g., F - , Cl - , Br - 、 I - ), and their corresponding cations (e.g., Li + , Na + , K + , NH4 + , Mg 2+ , Ca 2+). In certain embodiments, the concentration of the halide salt in the electrolyte can be anywhere from 0.01 to 50% by weight. In some embodiments, the electrolyte is introduced to the second electrode (e.g., the anode) by an inlet. In certain cases, the active material on the surface of the second electrode can include platinum, graphite, platinized titanium, mixed metal oxides, mixed metal oxide-coated titanium, platinized metal oxides (e.g., platinized lead oxide, manganese dioxide), platinized ferrosilicon, platinum-iridium alloy, ruthenium oxide, titanium oxide, ruthenium and / or titanium mixed metal oxides.

[0102] In some cases, at the second electrode in reactor 1, the halide anion is oxidized to produce a dihalide (e.g., Cl2, Br2, I2). For example, in one particular example, dissolved Cl - The oxidation of Cl2 gives Cl2 gas.

[0103] 2Cl - (aq) →Cl 2(g) +2e -

[0104] In certain embodiments, Br - The oxidation of Br2 gives the fuming liquid, and I - The oxidation of I2 gives solid I2. The dihalide is in some cases collected from the electrolytic cell via an outlet and used in a later step described below to produce an acid. In one particular example, the cation (e.g., Li + , Na + , K + 、 NH4 +The electrolyte, which contains the ions, migrates through a semi-permeable membrane (a diaphragm or an ion-exchange membrane) to the first electrode (e.g., a cathode). In some cases, the diaphragm or membrane prevents the alkaline solution generated at the first electrode from improving the pH at the second electrode. In certain embodiments, the surface of the first electrode may include an electrocatalytic compound. Examples of electrocatalytic compounds include platinum, platinized titanium, mixed metal oxide-coated titanium, platinized metal oxides (e.g., platinized lead oxide, manganese dioxide), platinized ferrosilicon, platinum-iridium alloys, stainless steel, graphite, unalloyed titanium, stainless steel, nickel, nickel oxide. In certain embodiments, the second electrode includes a metallic electrode such as platinum, gold, nickel, iridium, copper, iron, steel, stainless steel, manganese, and zinc, or carbon such as graphite or disordered carbon, or a metal carbide such as silicon carbide, titanium carbide, or tungsten carbide. In certain embodiments, the second electrode comprises a metal alloy (e.g., nickel-chromium-iron alloy, nickel-molybdenum-cadmium alloy), a metal oxide (e.g., iridium oxide, nickel iron cobalt oxide, nickel cobalt oxide, lithium cobalt oxide, lanthanum strontium cobalt oxide, barium strontium iron oxide, manganese molybdate, ruthenium dioxide, iridium ruthenium tantalum oxide), a metal-organic framework, or a metal sulfide (e.g., molybdenum sulfide). In certain embodiments, the electrocatalyst or electrode material is dispersed or coated on the conductive support surface. In some embodiments, as shown in FIG. 13A, at the first electrode (e.g., cathode) of reactor 1, water is reduced to OH. - (alkaline solution) and H 2(g) results.

[0105] H2O+2e - →H2+2OH -

[0106] In another embodiment, at the first electrode (e.g., cathode) of reactor 1, O2 is reduced to OH - (alkaline solution) is obtained. See Figure 13A.

[0107] 1 / 2O2+H2O+2e - →2OH -

[0108] In some embodiments, OH - The charge is balanced by cations in the electrolyte passing through a diaphragm or membrane, for example as shown in FIG. 13. In certain cases, an alkali hydroxide solution (e.g., NaOH, KOH) having an alkali concentration of 0.01 mol / L or higher and a pH higher than 7 is collected from the outlet of the reactor. In certain examples, H2 is collected from a different outlet of the reactor. In some cases, reactor 1 produces an alkaline solution at one electrode and hydrogen and a dihalide (if the metal salt is a metal halide) at the other electrode.

[0109] According to some embodiments, in FIG. 12, reactor 2 is a reactor that produces acid by reacting hydrogen gas and dihalides produced at the anode of reactor 1 or by reacting dihalides with water. Two embodiments of this reactor are shown in FIGS. 14A-14B, without being limited by the following examples. According to a particular embodiment, in FIG. 14A, the reactor comprises a first chamber, an inlet for introducing H2 into the first chamber, a second inlet for introducing dihalides into the first chamber, and an outlet for removing hydrogen halides (e.g., HCl, HBr, HI) from the first chamber, an inlet for introducing hydrogen halides into the second chamber, an inlet for introducing water into the second chamber, and an outlet for removing an acidic aqueous solution of hydrogen halides from the second chamber. In some embodiments, in the first chamber, the dihalides react with H2 to form hydrogen halides. In a particular embodiment, the reaction between H2 and dihalides may be assisted by heating or by irradiation with electromagnetic waves. For example, in some embodiments, when the dihalide is Cl, the following reaction occurs in reactor 2: Cl2+H2→2HCl

[0110] In some cases, in the second chamber, a hydrogen halide is dissolved in water to create an acidic solution. For example, HCl can be dissolved in water to create protons.

[0111] According to certain embodiments, in FIG. 14B, the dihalide reacts with water to produce the desired acid and oxygen as a by-product. In some cases, the exemplary reactor includes a first chamber, an inlet for introducing HO into the first chamber, and a second inlet for introducing the dihalide into the first chamber. In certain examples, the reactor also includes an outlet for removing hydrogen halide (e.g., HCl, HBr, HI) from the first chamber, and an outlet for removing O from the first chamber. In some cases, the reaction of chlorine as an exemplary dihalide with water is as follows:

[0112] Cl2+H2O→2HCl+1 / 2O 2.

[0113] In some embodiments, the relative amounts of dihalide and water determine whether pure hydrogen halide or a mixture of hydrogen halide and water, including, for example, an aqueous solution of hydrogen halide, is produced. Optionally, in certain embodiments, the reactor may include a second chamber in which hydrogen halide is dissolved in water to create an acidic solution, as shown in Figure 14B, the second chamber having an inlet for introducing hydrogen halide, an inlet for introducing water into the second chamber, and an outlet for removing the aqueous acidic solution of hydrogen halide from the reactor.

[0114] In some embodiments, the system includes an apparatus. For example, referring to FIG. 1A, in some embodiments, the system includes a first apparatus 118. Similarly, referring to FIG. 2C, in certain cases, the system includes a first apparatus 118. Similarly, referring to FIG. 3A, in some examples, the system includes a first apparatus 118. In certain examples, the apparatus is a container (e.g., a container that is not open to the atmosphere). According to certain embodiments, the apparatus is configured to collect one or more products or by-products of the reactor (e.g., acid, base, hydrogen gas, oxygen gas, and / or carbon dioxide gas, etc.), store one or more of the one or more products or by-products, and / or react one or more of the one or more products or by-products (e.g., in a chemical dissolution and / or precipitation reaction).

[0115] In certain embodiments, the system comprises a plurality of devices. In some embodiments, the system comprises more than or equal to 1, more than or equal to 2, more than or equal to 3, more than or equal to 4, or more than or equal to 5 devices. In some cases, the system comprises less than or equal to 6, less than or equal to 5, less than or equal to 4, less than or equal to 3, or less than or equal to 2 devices. Combinations of these ranges are also contemplated (e.g., 1-6 devices). In some embodiments, the system comprises a first device and a second device. For example, in FIG. 1B, in some embodiments, the system comprises a first device 118 and a second device 119. Similarly, referring to FIG. 2C, in certain embodiments, the system comprises a first device 118 and a second device 119. Similarly, referring to Figure 3A, in some cases, the system includes a first device 118 and a second device 119. Each device can have one or more independent functions. Any device or configuration of devices disclosed herein may be used with any system disclosed herein.

[0116] In certain embodiments, the device is fluidly coupled to the reactor. For example, in some examples, the device is coupled to the reactor by a conduit (e.g., a pipe, a channel, a needle, or a tube) through which a fluid can flow. For example, with reference to FIG. 1A, in some embodiments, the device 118 is fluidly coupled to the reactor by a conduit. Similarly, with reference to FIG. 2C, in certain embodiments, the device 118 is fluidly coupled to the reactor by a conduit. Similarly, with reference to FIG. 3A, in some examples, the device 118 is fluidly coupled to the reactor by a conduit.

[0117] In certain cases, a device is fluidly connected to one or more other devices (e.g., by a conduit such as a pipe, channel, needle, or tube). For example, with reference to FIG. 1D, the first device 118 is fluidly connected to the third device 120 by a conduit. Similarly, with reference to FIG. 2C, in some embodiments, the first device 118 may be fluidly connected to the third device (e.g., by a conduit). Similarly, with reference to FIG. 3A, in some cases, the first device 118 may be fluidly connected to the third device (e.g., by a conduit). As another example, referring to FIG. 1E, in some embodiments, the first device 118 is fluidly connected (e.g., by a conduit) to a third device 120, which is fluidly connected (e.g., by a conduit) to a fifth device 122, while the second device 119 is fluidly connected (e.g., by a conduit) to a fourth device 121, which is fluidly connected (e.g., by a conduit) to a sixth device 123.

[0118] According to some embodiments, the method includes collecting the acid and / or base. For example, in some embodiments, the method includes removing the acid and / or base from the vessel (e.g., reactor) in which they are produced. Non-limiting examples of suitable methods for collecting the acid and / or base include transferring the acid and / or base through a conduit (e.g., a pipe, channel, needle, or tube) to a separate vessel. Other suitable examples of collecting the acid and / or base include transferring the acid and / or base directly to a separate vessel (e.g., a vessel connected to the reactor by a panel that can be moved to block or allow the diffusion of fluids). In some embodiments, the acid and / or base is collected continuously or in batches. In certain embodiments, the acid and / or base is collected automatically or manually.

[0119] In some embodiments, the apparatus is configured to collect acid near the second electrode (and / or second reactor) and / or base near the first electrode (and / or first reactor) (e.g., collect acid from an acidic region and / or collect base from an alkaline region). For example, with reference to FIG. 1A, in some embodiments, the system includes a first apparatus 118 configured to collect base near the first electrode 104. Similarly, with reference to FIG. 2C, in certain embodiments, the system includes a first apparatus 118 configured to collect base near the first electrode 104. Similarly, with reference to FIG. 3A, the system 300 includes a first apparatus 118 configured to collect base near the first reactor 320 (e.g., near the first electrode 104 of the first reactor 320). In some embodiments, the first apparatus 118 may be configured to collect acid adjacent to the second electrode (and / or second reactor) in addition to or instead of collecting base adjacent to the first electrode (and / or first reactor).

[0120] In certain embodiments, the second device is configured to collect the acid near the second electrode (and / or the second reactor) and / or the base near the first electrode (and / or the first reactor). In some embodiments where the first device collects the base near the first electrode, the second device is configured to collect the acid near the second electrode. For example, referring to FIG. 1B, in some embodiments, the system includes a first device 118 and a second device 119, and in certain cases, the first device 118 is configured to collect the base near the first electrode 104 and the second device 119 is configured to collect the acid near the second electrode 105. Similarly, with reference to FIG. 2C, in certain embodiments, the system includes a first apparatus 118 and a second apparatus 119, where in certain cases the first apparatus 118 is configured to collect a base near the first electrode 104 and the second apparatus 119 is configured to collect an acid near the second electrode 105. Similarly, in FIG. 3A, in some examples, the system 300 includes a first apparatus 118 and a second apparatus 119, where in certain cases the first apparatus 118 is configured to collect a base near the first reactor 320 (e.g., the first electrode 104) and the apparatus 119 is configured to collect an acid near the second reactor 301. Alternatively, in embodiments in which the first apparatus is configured to collect acid proximate the second electrode (and / or the second reactor), the second apparatus may be configured to collect base proximate the first electrode (and / or the first reactor).

[0121] In certain embodiments, collecting the acid includes collecting the acid produced by the electrode from a close enough vicinity to the electrode that the acid is not significantly diluted and / or reacted (e.g., the pH of the collected acid is within 1 pH unit of the acid having the lowest pH in the reactor). Similarly, in some embodiments, collecting the base includes collecting the base produced by the electrode from a close enough vicinity to the electrode that the salt is not significantly diluted and / or reacted (e.g., the pH of the collected base is within 1 pH unit of the base having the highest pH in the reactor).

[0122] According to some embodiments, the method includes storing the acid and / or base. For example, in certain embodiments, once the acid and / or base are collected in the separate container, the method includes maintaining the acid and / or base in the separate container for at least some period of time. In some embodiments, the method includes storing the acid and / or base for more than or equal to 5 minutes, more than or equal to 15 minutes, more than or equal to 30 minutes, more than or equal to 1 hour, more than or equal to 5 hours, more than or equal to 12 hours, more than or equal to 1 day, more than or equal to 2 days, more than or equal to 3 days, more than or equal to 1 week, more than or equal to 2 weeks, or more than or equal to 1 month. In certain embodiments, the method includes storing the acid and / or base for less than or equal to 1 year, less than or equal to 6 months, less than or equal to 3 months, less than or equal to 2 months, less than or equal to 1 month, less than or equal to 2 weeks, less than or equal to 1 week, less than or equal to 3 days, less than or equal to 2 days, less than or equal to 1 day, or less than or equal to 12 hours. Combinations of these ranges are also contemplated (e.g., greater than or equal to 5 minutes and less than or equal to 1 year, greater than or equal to 5 hours and less than or equal to 1 day, or greater than or equal to 1 week and less than or equal to 1 year).

[0123] In certain embodiments, the devices (e.g., the first device and / or the second device) are configured to store an acid and / or a base. For example, with reference to FIG. 1A, in some embodiments, the first device 118 is configured to store a base. Similarly, with reference to FIG. 2C, in certain embodiments, the first device 118 is configured to store a base. Similarly, with reference to FIG. 3A, in some cases, the first device 118 is configured to store a base.

[0124] As another example, referring to Figure 1B, in some embodiments, the second device 119 is configured to store a base. Similarly, referring to Figure 2C, in certain cases, the second device 119 is configured to store an acid. Similarly, referring to Figure 3A, in some examples, the second device 119 is configured to store an acid.

[0125] In some embodiments, when the first device is configured to store a base, the second device is configured to store an acid. For example, referring to FIG. 1B, in some embodiments, the system comprises a first device 118 and a second device 119, in a particular case, the first device 118 is configured to store a base, and the second device 119 is configured to store an acid. Similarly, referring to FIG. 2C, in some examples, the system comprises a first device 118 and a second device 119, in a particular case, the first device 118 is configured to store a base, and the second device 119 is configured to store an acid. Similarly, referring to FIG. 3A, according to a particular embodiment, the system comprises a first device 118 and a second device 119, in a particular case, the first device 118 is configured to store a base, and the second device 119 is configured to store an acid. Alternatively, in embodiments in which the first device is configured to store an acid, the second device may be configured to store a base.

[0126] According to some embodiments, the method includes reacting an acid and / or a base in a chemical dissolution and / or precipitation reaction. In certain embodiments, the chemical dissolution is prior to the precipitation reaction (e.g., the products of the chemical dissolution are used in the precipitation reaction). In some cases, the precipitation reaction is prior to the chemical dissolution (e.g., the products of the precipitation reaction are used in the chemical dissolution). In certain instances, the chemical dissolution and precipitation reactions are simultaneous and / or unrelated (e.g., the products of one are not used in the other and vice versa).

[0127] In some embodiments, the apparatus (e.g., the first apparatus and / or the second apparatus) is configured to react with an acid in a chemical dissolution and / or precipitation reaction. For example, with reference to FIG. 1B, in some embodiments, the second apparatus 119 is configured to react with an acid (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, with reference to FIG. 2C, in certain embodiments, the second apparatus 119 is configured to react with an acid (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, with reference to FIG. 3A, according to certain embodiments, the second apparatus 119 is configured to react with an acid (e.g., in a chemical dissolution and / or precipitation reaction).

[0128] In certain embodiments, the apparatus (e.g., the first apparatus and / or the second apparatus) is configured to react a base in a chemical dissolution and / or precipitation reaction. As another example, with reference to FIG. 1A, in certain embodiments, the first apparatus 118 is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, with reference to FIG. 2C, in some embodiments, the first apparatus 118 is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, with reference to FIG. 3A, according to some embodiments, the first apparatus 118 is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction).

[0129] In some embodiments, when the first device is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction), the second device is configured to react an acid (e.g., in a chemical dissolution and / or precipitation reaction). For example, referring to FIG. 1B, in some embodiments, the system includes a first device 118 and a second device 119, and in certain cases, the first device 118 is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction), and the second device 119 is configured to react an acid (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, referring to FIG. 2C, in certain embodiments, the system includes a first device 118 and a second device 119, and in certain cases, the first device 118 is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction), and the second device 119 is configured to react an acid (e.g., in a chemical dissolution and / or precipitation reaction). 3A, according to certain embodiments, the system includes a first device 118 and a second device 119, where in certain cases the first device 118 is configured to react a base (e.g., in a chemical dissolution and / or precipitation reaction) and the second device 119 is configured to react an acid (e.g., in a chemical dissolution and / or precipitation reaction). Alternatively, in embodiments where the first device is configured to react an acid, the second device may be configured to react a base.

[0130] According to certain embodiments, the devices (e.g., the first device and / or the second device) may be configured to (i) collect an acid near the second electrode and / or a base near the first electrode, (ii) store the acid and / or base, and / or react the acid and / or base (e.g., in a chemical dissolution and / or precipitation reaction). For example, with reference to FIG. 1A, in some embodiments, the first device 118 is configured to (i) collect a base near the first electrode, (ii) store the base, and (iii) react the base (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, with reference to FIG. 2C, in certain embodiments, the first device 118 is configured to (i) collect a base near the first electrode, (ii) store the base, and (iii) react the base (e.g., in a chemical dissolution and / or precipitation reaction). Similarly, with reference to FIG. 3A , in some cases, the first device 118 is configured to (i) collect the base proximate the first electrode, (ii) store the base, and (iii) react the base (e.g., in a chemical dissolution and / or precipitation reaction).

[0131] As another example, referring to FIG. 1B, in some embodiments, the second device 119 is configured to (i) collect acid in the vicinity of the second electrode, (ii) store the acid, and (iii) react the acid (e.g., chemically dissolve and / or precipitate). Similarly, referring to FIG. 2C, in certain embodiments, the second device 119 is configured to (i) collect acid in the vicinity of the second electrode, (ii) store the acid, and (iii) react the acid (e.g., chemically dissolve and / or precipitate). Similarly, referring to FIG. 3A, the second device 119 is configured to (i) collect acid in the vicinity of the second electrode, (ii) store the acid, and (iii) react the acid (e.g., chemically dissolve and / or precipitate).

[0132] According to some embodiments, each device may have only one function. For example, in one particular embodiment, a first device is configured to collect a base near a first electrode, a second device is configured to collect an acid near a second electrode, and a third device is configured to react the base and / or the acid (e.g., in a chemical dissolution and / or precipitation reaction). For example, in FIG. 1D, in one particular embodiment, a first device 118 is configured to collect a base near a first electrode 104, a second device 119 is configured to collect an acid near a second electrode 105, and a third device 120 is configured to react the base (e.g., in a chemical dissolution and / or precipitation reaction). As another non-limiting example, in some embodiments, a first device is configured to collect a base near a first electrode and store the base, a second device is configured to collect an acid near a second electrode and store the acid and react the acid (e.g., in a chemical dissolution and / or precipitation reaction), and a third device is configured to react the base (e.g., in a chemical dissolution and / or precipitation reaction). For example, in FIG. 1D, in some embodiments, a first device 118 is configured to collect a base near a first electrode 104 and store the base, a second device 119 is configured to collect an acid near a second electrode 105 and store the acid and react the acid (e.g., in a chemical dissolution and / or precipitation reaction), and a third device 120 is configured to react the base (e.g., in a chemical dissolution and / or precipitation reaction).

[0133] In yet another example, in some embodiments, a first device is configured to collect a base proximate a first electrode, a second device is configured to collect an acid proximate a second electrode, a third device is configured to store a base, a fourth device is configured to store an acid, a fifth device is configured to react the base (e.g., in a chemical dissolution and / or precipitation reaction), and a sixth device is configured to react the acid (e.g., in a chemical dissolution and / or precipitation reaction). For example, in FIG. 1E , in some examples, a first device 118 is configured to collect a base near the first electrode 104, a second device 119 is configured to collect an acid near the second electrode 105, a third device 120 is configured to store a base, a fourth device 121 is configured to store an acid, a fifth device 122 is configured to react the base (e.g., in a chemical dissolution and / or precipitation reaction), and a sixth device 123 is configured to react the acid (e.g., in a chemical dissolution and / or precipitation reaction).

[0134] In some embodiments, the acid and / or base described herein react in a chemical dissolution and / or precipitation reaction. In certain cases, the acid and / or base react in a chemical dissolution. In some embodiments, the chemical dissolution includes dissolving a solid to form two stable ions. In some embodiments, the solid includes a metal, a metal alloy, a metalloid, a metal salt, a metal oxide, a metal hydroxide, and / or a silicate. In certain embodiments, the solid is crystalline, amorphous, nanocrystalline, and / or a mixture thereof. In some embodiments, the solid includes Ag, Al, As, Au, Ba, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Ti, Tl, V, W, and / or Zn (e.g., in elemental form or as a salt).

[0135] In some embodiments, the metals and / or metal alloys include iron, iron alloys, stainless steel, non-ferrous metals, non-ferrous alloys, aluminum, brass, bronze, copper, zinc, tin, and / or coin alloys.

[0136] Examples of metal salts, metal oxides, and metal hydroxides include calcium, magnesium, barium, strontium, manganese, iron, cobalt, zinc, cadmium, lead, and / or nickel salts, oxides, and hydroxides. For example, in some embodiments, the metal salt comprises a metal carbonate. Examples of suitable metal carbonates include calcium carbonate, magnesium carbonate, barium carbonate, strontium carbonate, manganese carbonate, iron carbonate, cobalt carbonate, zinc carbonate, cadmium carbonate, lead carbonate, and / or nickel carbonate.

[0137] Examples of suitable metal oxides include calcium oxide, magnesium oxide, strontium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, cadmium oxide, lead oxide, silicon dioxide and / or aluminum oxide.

[0138] Examples of suitable metal hydroxides include calcium hydroxide, magnesium hydroxide, strontium hydroxide, manganese hydroxide, iron oxide, cobalt hydroxide, nickel hydroxide, zinc hydroxide, cadmium hydroxide, lead hydroxide, silicon hydroxide and / or aluminum hydroxide.

[0139] In some embodiments, the acid reacts with the metal, metal alloy, metalloid, metal salt, metal oxide, and / or metal hydroxide chemically. In certain embodiments, the base reacts with the metal oxide (e.g., silicon dioxide and / or aluminum oxide) and / or metal hydroxide (e.g., silicon hydroxide and / or aluminum hydroxide).

[0140] In some examples, the acid and / or base are reacted in a precipitation reaction. In certain embodiments, the precipitation reaction involves two stable ions coming together to form a solid precipitate. In some embodiments, the solid precipitate comprises a metal hydroxide. Examples of suitable metal hydroxides include calcium hydroxide, magnesium hydroxide, barium hydroxide, strontium hydroxide, manganese hydroxide, iron hydroxide, cobalt hydroxide, zinc hydroxide, cadmium hydroxide, lead hydroxide, and / or nickel hydroxide.

[0141] According to some embodiments, a base is reacted in a precipitation reaction to form a metal hydroxide, in certain embodiments, an acid is reacted in a precipitation reaction to form a metal hydroxide.

[0142] In certain embodiments, the reactor is operated intermittently when in the first mode (e.g., as described above). In some cases, the reactor is operated continuously in the first mode. In certain instances, the reactor is operated intermittently in the first mode while a reaction with the collected acid and / or base (e.g., a chemical dissolution and / or precipitation reaction) is carried out continuously. For example, in some embodiments, the reactor produces enough acid and / or base when operated in the first mode only when it needs to be operated intermittently to produce enough acid and / or base to carry out a reaction (e.g., a chemical dissolution and / or precipitation reaction) continuously.

[0143] In some embodiments, the desired chemical reaction is carried out by collecting solutions or suspensions of various compositions produced by electrolysis and using the solution(s) to produce products from the reactants in parts of the reactor or in individual devices. For example, Figures 4A-4B show a reactor in which an electrolytic cell produces low and high pH solutions oriented to isolate individual sections of the reactor or to isolate the reactor, according to certain embodiments. In this process, according to some embodiments, in the first chamber, an acidic solution is used to dissolve CaCO3 and release CO2 gas (see Figure 4B). In the second chamber, in some embodiments, the dissolved solution reacts with an alkaline solution produced by the electrolytic cell to produce Ca(OH)2 (see Figure 4B). In some embodiments, the two chambers provide reservoirs for the acidic and alkaline solutions. In certain embodiments, the reservoir for the acid comprises a lining of a polymeric material or glass. In certain embodiments, the reservoir for the alkaline comprises a polymeric material or metal. In some embodiments, the metal bath comprises iron or steel.

[0144] In certain cases, the by-product of the precipitation reaction is fed back to the system (e.g., the first reactor). In some cases, the system is configured to feed the by-product from the precipitation reaction to the system (e.g., the first reactor). In some embodiments, the by-product has a neutral pH. For example, in certain cases, the by-product has a pH greater than 6, greater than or equal to 6.25, greater than or equal to 6.5, greater than or equal to 6.75, or greater than or equal to 6.9. In some cases, the by-product has a pH less than 8, less than or equal to 7.75, less than or equal to 7.5, less than or equal to 7.25, or less than or equal to 7.1. Combinations of these ranges are also contemplated (e.g., greater than 6 and less than 8, or greater than or equal to 6.9 and less than or equal to 7.1). In some embodiments, the by-product has a pH of 7.

[0145] In some cases, the by-products include alkali halides (e.g., by-products during precipitation of alkali hydroxides) (e.g., NaCl). In certain cases, the by-products include alkali salts (e.g., NaClO4, NaNO3, sodium trifluoromethanesulfonate, and / or sodium acetate).

[0146] In some embodiments, the method includes operating the reactor in a second mode. In certain cases, the polarity of the reactor is reversed in the second mode compared to the polarity of the reactor in the first mode. According to some embodiments, operating the reactor in the first mode uses more electricity than operating the reactor in the second mode. For example, in certain embodiments, operating the reactor in the first mode uses at least 10%, at least 20%, at least 30%, or at least 40% more electricity than operating the reactor in the second mode. In some cases, operating the reactor in the first mode uses less than or equal to 50%, less than or equal to 40%, less than or equal to 30%, or less than or equal to 20% more electricity than operating the reactor in the second mode. Combinations of these ranges are also contemplated (e.g., at least (at elast) 10% and less than or equal to 50%). Any embodiment related to the second mode may be applied to any of the systems described herein.

[0147] In some embodiments, operating the reactor in the second mode includes adding a base to the reactor near the second electrode. For example, in certain embodiments, operating the reactor in the second mode includes adding a base to the reactor so that the base is available for electrochemical reactions at the second electrode. For example, with reference to FIG. 1A, in some embodiments, operating the reactor in the second mode includes adding a base near the second electrode 105. Similarly, with reference to FIG. 2A, in certain embodiments, operating the reactor in the second mode includes adding a base near the second electrode 105. According to some embodiments, when the reactor is operated in the first mode, the base added to the reactor is collected from the vicinity of the first electrode and stored until the reactor is operated in the second mode. In certain embodiments, operating the reactor in the second mode includes oxidizing the base added near the second electrode (e.g., the stored base) to produce oxygen gas. For example, in some cases, operating the reactor in the second mode includes oxidizing an added base to oxygen gas by a second electrode.

[0148] In certain embodiments, operating the reactor in the second mode includes adding an acid to the reactor in the vicinity of the first electrode. For example, in certain embodiments, operating the reactor in the second mode includes adding an acid to the reactor so that the acid can be used for an electrochemical reaction at the first electrode. For example, with reference to FIG. 1A, in some embodiments, operating the reactor in the second mode includes adding an acid in the vicinity of the first electrode 104. Similarly, with reference to FIG. 2A, in certain embodiments, operating the reactor in the second mode includes adding an acid in the vicinity of the first electrode 104. According to some embodiments, the acid added to the reactor is collected from the vicinity of the second electrode when the reactor is operated in the first mode and stored until the reactor is operated in the second mode. In certain embodiments, operating the reactor in the second mode includes reducing the acid added in the vicinity of the first electrode (e.g., the stored acid) to produce hydrogen gas. For example, in some cases, operating the reactor in the second mode includes reducing an added acid to hydrogen gas by a first electrode.

[0149] In contrast, in some embodiments, operating the reactor in the first mode includes adding a nearly neutral input solution to the reactor. In certain cases, the nearly neutral input solution has a pH greater than 6, greater than or equal to 6.25, greater than or equal to 6.5, greater than or equal to 6.75, or greater than or equal to 6.9. In some examples, the nearly neutral input solution has a pH less than 8, less than or equal to 7.75, less than or equal to 7.5, less than or equal to 7.25, or less than or equal to 7.1. Combinations of these ranges are also contemplated (e.g., greater than 6 and less than 8, or greater than or equal to 6.9 and less than or equal to 7.1). In some embodiments, the nearly neutral input solution has a pH of 7. In certain embodiments, the nearly neutral input solution includes a salt. Examples of suitable salts include alkali sulfates, alkali chlorates, alkali halides, alkali nitrates, alkali perchlorates, alkali acetates, alkali nitrites, and / or alkali trifluoromethanesulfonates.

[0150] In some embodiments, when electricity costs are high and / or electricity is scarce, it may be advantageous to operate the reactor in the second mode rather than the first mode. For example, in certain embodiments, when electricity is purchased from a power supplier, there may be fluctuations in the cost and / or availability of electricity from the power supplier, and when electricity costs are low and / or electricity availability is high, it may be advantageous to operate the reactor in the first mode, and then when electricity costs are high and / or electricity availability is low, it may be advantageous to operate the reactor in the second mode. As another example, when electricity comes from a renewable source such as solar energy or wind energy, in certain embodiments, there may be fluctuations in the availability of electricity, and thus when electricity availability is high (e.g., in the case of solar energy, during the day and / or summer, or in the case of wind energy, during periods of high wind), it may be advantageous to operate the reactor in the first mode, and when electricity availability is low (e.g., in the case of solar energy, during the night and / or winter, or during periods without significant wind), it may be advantageous to operate the reactor in the second mode. In some cases, the reactor is operated in a first mode when the cost of electricity is a first cost and the availability of electricity is a first availability, and the reactor is operated in a second mode when the cost of electricity is a second cost and the availability of electricity is a second availability, where the second cost is higher than the first cost (e.g., at least 10%, 25%, 50% or 100% higher) and / or the first availability is higher than the second availability (e.g., at least 10%, 25%, 50% or 100% higher).

[0151] In some embodiments, during periods of high electricity availability and / or low electricity cost, the acidic and / or basic solutions produced by the electrolysis reactor are at least partially collected and / or stored to allow for a chemical dissolution reaction in the acid to produce CO2 and a chemical precipitation reaction in the base to occur during periods of low or low electrolytic cell operation or electricity availability and / or high electricity cost. In some embodiments, the storage of the acidic and basic solutions acts as a chemical storage, allowing the output of chemically reacted products, which may generally be solid, liquid or gas, to be less variable or smoother than the rate of output of the electrolytic cell. In some embodiments, the stored acidic or basic solutions are of a size or volume capable of producing chemically reacted products at a rate that does not completely deplete the stored acidic or basic solutions during periods of low or low electrolytic cell operation or electricity availability and / or high electricity cost. In some embodiments, the system comprises a variable electricity source, the electrolytic cell and the chemical storage tank and a chemical reactor. In some embodiments, the methods further include operating such a system to produce a less fluctuating or constant or relatively constant flow of chemical reaction products from a variable or intermittent electrical source.

[0152] In certain embodiments, the method includes generating an acid and a base in a low voltage mode (e.g., at a lower voltage than the high voltage mode described herein). Any embodiment relating to the low voltage mode can be used with any of the systems disclosed herein. In some embodiments, the method does not generate oxygen gas and / or hydrogen gas. For example, in certain embodiments, the electrolysis reaction performed in the low voltage mode is the oxidation of hydrogen (H2→2H2) at the second electrode. + +2e - ), and the reduction of water at the first electrode (2H2O+2e - →H2+2OH -), thus not producing oxygen gas. In another example, in certain embodiments, the electrolysis reaction carried out in the low voltage mode is the oxidation of water (2H2O→O2+4H + +4e - ), and the reduction of oxygen at the second electrode (O2 + 2H2O + 4e - →4OH - ), thus no hydrogen gas is produced.

[0153] To illustrate, some exemplary systems are described below. System 1: An exemplary system for producing low-cost H2 at a constant rate using intermittent renewable energy

[0154] According to some embodiments, the system can include a reactor that includes a region that includes a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In some embodiments, the reactor can include a first electrode and a second electrode, one or more inlets that provide a liquid and / or gas that undergoes the electrolytic reaction(s), and a portion of the reactor or a separate device that stores the solution after undergoing the electrolytic reaction.

[0155] In certain embodiments, the method includes operating the reactor in a first mode (e.g., the high voltage mode shown in FIGS. 5A-5B), the first mode including generating a base proximate a first electrode, generating an acid proximate a second electrode in the reactor that is electrochemically connected to the first electrode, collecting the acid and / or base, and reacting the collected acid and / or base in a chemical dissolution and / or precipitation reaction.

[0156] In certain embodiments, the electrolysis reaction can produce H2, O2, acidic solutions, and basic solutions. This is an example of a high voltage mode, which requires a higher voltage than the low voltage mode. A non-limiting example of an electrolysis reaction that can occur in the high voltage mode is the oxidation of water at the second electrode (2H2O→O2+4H ++4e - ) and the reduction of water at the first electrode (2H2O+2e - →H2+2OH - ). This reaction requires a minimum voltage of 2V when the pH at the second electrode is 0 and the pH at the first electrode is 14 (see FIGS. 5A-5B). In certain embodiments, the acidic and basic solutions produced at the electrodes can be collected and stored separately.

[0157] In certain embodiments, the method includes operating the reactor in a second mode (e.g., low voltage mode, as shown in FIGS. 6A-6B). In some embodiments, the polarity of the reactor is reversed in the second mode compared to the polarity of the reactor in the first mode. In some embodiments, the second mode includes adding collected and / or stored base to the reactor proximate the second electrode. In certain embodiments, the second mode includes oxidizing the base added proximate the second electrode to produce oxygen gas. In some embodiments, the second mode includes adding collected and / or stored acid to the reactor proximate the first electrode. In certain embodiments, the second mode includes reducing the acid added proximate the first electrode to produce hydrogen gas.

[0158] In certain embodiments, the electrolysis reaction may neutralize acidic and basic solutions with the simultaneous production of H2 and O2. This is an example of a low voltage mode, which requires a lower voltage than the high voltage mode described above. A non-limiting example of an electrolysis reaction that can be performed in low voltage mode is the oxidation of hydroxide ions (4OH) at the second electrode (e.g., the anode). - →O2+2H2O+4e - ) and the reduction of protons (2H + +2e -→H2). This reaction requires a minimum voltage of 0.4 V when the pH at the second electrode is 14 and the pH at the first electrode is 0 (see Figures 6A-6B). In certain embodiments, the reactor inlet can supply the second electrode with a solution having a pH greater than 8 and the first electrode with a solution having a pH less than 6.

[0159] In certain embodiments, different reactors may be operated in high voltage mode and low voltage mode. In another embodiment, a single reactor may be configured to be able to operate in high voltage mode or low voltage mode. In some embodiments, the reactors can be switched from high voltage mode to low voltage mode by changing the pH of the liquid flowing toward the electrodes. For example, to switch from high voltage mode to low voltage mode, an acidic solution can be introduced to the first electrode while an alkaline solution can be introduced to the second electrode.

[0160] In some embodiments, the decision to switch between high voltage mode (e.g., producing H2 / O2 while producing acid / base) and low voltage mode (e.g., producing H2 / O2 while neutralizing acid / base) can be based on the cost of electricity or availability of electricity, which can vary throughout a day, month, or year. In certain embodiments, if the cost of electricity is below a certain value, the reactor can be operated in high voltage mode (e.g., consuming more power while producing H2, O2, acid, and base). If the cost of electricity is above a certain value, the reactor can be operated in low voltage mode (e.g., consuming less power while producing H2 and O2 using acid and base solutions). In some embodiments, the system can effectively arbitrage the cost of electricity to produce H2: when electricity is cheap, the system uses more electricity by operating in high voltage mode, where some of the cheap electrical energy is converted into chemical energy that can be physically stored (e.g., in the form of acid and base solutions). When electricity is expensive, the system can use less electricity by operating in a low voltage mode, which can use stored chemical energy (e.g., acidic and basic solutions) to lower the energy requirements for producing H2 and O2. In some embodiments, the system can operate to reduce the cost of electricity to produce H2 and O2. In some embodiments, the system can operate to produce hydrogen and oxygen at a constant rate using electricity that fluctuates in price or availability.

[0161] FIG. 7 illustrates a non-limiting example of how a system using up to 20% intermittent renewable electricity reduces energy costs to produce H2. In this example, the cost of renewable energy varies between 0.02$ / kWh and 0.07$ / kWh (complying with a typical wind turbine energy production rate on a typical day). Electricity costs versus time for a 1 kW alkaline or PEM electrolyser operated at fixed voltage (1.2V, 32kWh / kg H2) are shown in FIG. 7. FIG. 7 also shows the energy costs of a variable voltage electrolyser operating in high voltage mode (2V, 54kWh / kg H2) when electricity costs are below average (0.05$ / kWh) and in low voltage mode (0.4V, 10kWh / kg H2) when electricity costs are above average, according to some embodiments. In this example, both electrolysers produce H2 at the same rate and use the same amount of energy on average (32 kWh / kg H2), but the energy costs of running the two cells are different. In this example, the variable voltage electrolyser uses less expensive electricity (due to operation in low voltage mode) and more cheap electricity (due to operation in high voltage mode). In this example, the average energy cost of the fixed voltage electrolyser is 0.05$ / kWh and the average energy cost of the variable voltage electrolyser is 0.04$ / kWh (20% less). It is noted that according to some embodiments, the possible cost savings in the case of the variable voltage electrolyser are proportional to the magnitude of the cost variation: the greater the variation in electricity cost, the greater the cost savings. System 2: An exemplary system for low-cost hydrogen and acid / base solution co-generation using intermittent renewable electricity

[0162] According to some embodiments, the system can include a reactor that includes a region that includes a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In some embodiments, the reactor can include a first electrode and a second electrode, one or more inlets that provide liquid and / or gas that undergoes the electrolytic reaction(s), and a portion of the reactor or a separate device that stores the solution after undergoing the electrolytic reaction. In some embodiments, the electrolytic reaction can result in a pH of less than about 6 in the vicinity of the second electrode and a pH of greater than about 8 in the vicinity of the first electrode. The high and low pH solutions can be collected and stored separately. In some embodiments, the electrodes can be configured to perform one or more of the electrolytic reactions to generate a high or low pH solution.

[0163] In certain embodiments, the electrolysis reaction can produce H2, O2, acidic solutions, and basic solutions. This is an example of a high voltage mode, which requires a higher voltage than the low voltage mode. A non-limiting example of an electrolysis reaction that can occur in the high voltage mode is the oxidation of water (2H2O→O2+4H2O) at the second electrode (e.g., the anode). + +4e - ) and the reduction of water (2H2O+2e - →H2+2OH - ). This reaction requires a minimum voltage of 2V when the pH at the second electrode is 0 and the pH at the first electrode is 14 (see FIGS. 5A-5B). In certain embodiments, the acidic and basic solutions produced at the electrodes can be collected and stored separately.

[0164] In certain embodiments, the reactor can sometimes produce acidic and basic solutions in a low voltage mode, which requires less voltage than the high voltage mode. Non-limiting examples of electrolytic reactions that produce acidic and basic solutions in a low voltage mode include the following:

[0165] In certain embodiments, the electrolysis reaction carried out in the low voltage mode is the oxidation of hydrogen (H2→2H2O2) at the second electrode (e.g., the anode). + +2e - ) and the reduction of water (2H2O+2e - →H2+2OH - ) (e.g., the HRR / HER reaction). This reaction requires a minimum voltage of 0.8 V when the pH at the second electrode is 0 and the pH at the first electrode is 14 (see FIGS. 8A-8B).

[0166] In certain embodiments, the electrolysis reaction carried out in the low voltage mode is the oxidation of water (2H2O→O2+4H2O) at the second electrode (e.g., the anode). + +4e - ) and the reduction of oxygen (O2 + 2H2O + 4e - →4OH - ) (e.g., OER / ORR reaction). This reaction requires a minimum voltage of 0.8 V when the pH at the second electrode is 0 and the pH at the first electrode is 14 (see Figures 9A-9B).

[0167] In some embodiments, the decision to switch between high voltage mode (e.g., acid / base production with simultaneous production of H2 / O2) or low voltage mode (e.g., acid / base production with no net amount of gas production) can be based on the cost or availability of electricity, which can vary throughout a day, month, or year. In certain embodiments, if the cost of electricity is below a certain value, the reactor can be run in high voltage mode (e.g., H2, O2 production). 2、 (e.g., consuming more power while producing acid and base). In certain embodiments, if the electricity cost exceeds a certain value, the reactor can be operated in low voltage mode (e.g., producing only acid and base, consuming less power).

[0168] In some embodiments, the system can take advantage of low electricity prices by co-producing H2 and O2 along with acid and base solutions: when electricity is cheap, the system can use more electricity by operating in a high voltage mode that produces acid, base, H2, and O2. When electricity is expensive, the system can use less electricity by operating in a low voltage mode that produces acid and base, but no net amounts of H2 or O2. In some embodiments, the system acts to reduce the cost of electricity to produce H2 and O2. System 3: An exemplary system for low-cost acid / base production at a constant rate using intermittent renewable energy.

[0169] According to some embodiments, the system can include a reactor that includes a region that includes a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In some embodiments, the reactor can include a first electrode and a second electrode, one or more inlets that provide liquid and / or gas that undergoes the electrolytic reaction(s), and a portion of the reactor or a separate device that stores the solution after undergoing the electrolytic reaction. In some embodiments, the electrolytic reaction can result in a pH of less than about 6 in the vicinity of the second electrode and a pH of greater than about 8 in the vicinity of the first electrode. The high and low pH solutions can be collected and stored separately. In some embodiments, the electrodes can be configured to perform one or more of the electrolytic reactions to generate a high or low pH solution.

[0170] In certain embodiments, the electrolysis reactions can produce H2, O2, acidic solutions, and basic solutions. This electrolysis mode requires a higher voltage than the fuel cell mode described below, and is therefore an example of an electrolysis mode. A non-limiting example of an electrolysis reaction that occurs in the electrolysis mode is the oxidation of water (2H2O→O2+4H2O) at the second electrode (e.g., the anode). + +4e - ) and the reduction of water (2H2O+2e- →H2+2OH - ). This reaction requires a minimum voltage of 2V when the pH at the second electrode is 0 and the pH at the first electrode is 14 (see FIGS. 5A-5B). In certain embodiments, the acidic and basic solutions produced at the electrodes can be collected and stored separately.

[0171] In certain embodiments, the reaction carried out in the fuel cell mode is the oxidation of hydrogen (H2→2H2O2) at the second electrode (e.g., the anode). + +2e - ) and the reduction of oxygen (O2 + 2H2O + 4e - →4OH - ) (e.g., HRR / ORR reactions), which result in a spontaneous reaction that produces energy (see Figures 10A-10B).

[0172] In some embodiments, the system can effectively arbitrage the cost of electricity to produce acid and base solutions: when electricity is cheap, the system uses more electricity by operating in electrolysis mode, where a portion of the cheap electrical energy is converted into chemical energy that can be physically stored (in the form of H2 and O2 gases). When electricity is expensive, the system can use less electricity by operating in fuel cell mode, where the stored chemical energy (H2 and O2 gases) can be used to produce acids, bases, and electricity. In some embodiments, the system operates to reduce the cost of electricity to produce acid and base solutions. In some embodiments, the system operates to produce acid and base solutions at a constant rate using electricity that fluctuates in price or availability.

[0173] In some embodiments, the chemical dissolution and / or precipitation reaction takes place inside a reactor.

[0174] According to certain embodiments, the reactor includes a spatially varying chemical composition gradient between the first electrode and the second electrode. In some embodiments, the spatially varying chemical composition gradient includes a spatially varying pH gradient. For example, referring to FIG. 2B, in some cases, the system 200 includes an alkaline region 106 near the first electrode 104 and an acidic region 107 near the second electrode 105. Thus, the system 200 includes a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) between the first electrode and the second electrode. In some embodiments, the first region includes an acidic region. In certain embodiments, the second region includes an alkaline region. In other embodiments, the first region includes an alkaline region and the second region includes an acidic region.

[0175] In some embodiments, the reactor is configured such that a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) is established and / or maintained, at least in part, by electrolysis. For example, with reference to FIG. 2B, in one particular example, the system 200 includes a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) comprising an alkaline region 106 and an acidic region 107. In some such embodiments, the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) is established and / or maintained by electrolysis. According to some embodiments, electrolysis of a neutral electrolyte can produce a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient) between electrodes, such as the first electrode 104 and the second electrode 105. In some embodiments, an electrolysis reaction is used to produce a chemical composition gradient between the positive and negative electrodes of an electrochemical cell.

[0176] According to certain embodiments, a chemical composition gradient created by electrolysis can be used to effect a desired chemical reaction by providing reactants to a chemical environment proximate one electrode and using the chemical composition gradient created by electrolysis to generate products from the reactants as they diffuse toward the other electrode, or their components.

[0177] In some embodiments, electrolysis includes hydrolysis. As used herein, hydrolysis refers to the electrolysis of water. For example, in some embodiments, the reaction occurring at the cathode is the conversion of two H2O molecules and two electrons to H2 and two OH - while a reaction occurring at the anode converts two HO molecules into four electrons, O and four protons. In some embodiments, the production of hydroxide ions near the first electrode 104 establishes and / or maintains an alkaline pH near the first electrode 104, establishing and / or maintaining an alkaline region 106, while the production of protons near the second electrode 105 establishes an acidic pH near the second electrode 105, establishing and / or maintaining an acidic region 107. Thus, in certain embodiments, the reactor is configured such that a spatially-varying chemical composition gradient (e.g., a spatially-varying pH gradient) is established and / or maintained, at least in part, by hydrolysis.

[0178] According to certain embodiments, the reactor comprises an inlet coupled to a first region (e.g., an acidic region) of a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In certain embodiments, the electrochemical reactor and / or the inlet are configured to receive a solid (e.g., CaCO3).

[0179] In some embodiments, the reactor comprises a reactor outlet. In some embodiments, the reactor outlet is configured to remove Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (CaO). In some embodiments, the reactor comprises an outlet coupled to a second region (e.g., an alkaline region) of the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In certain embodiments, the outlet is configured to allow solids to be withdrawn from the reactor. In some embodiments, the reactor comprises a solids handling device associated with the outlet and configured to remove solids from the reactor. For example, in some embodiments, the solids handling device is configured to remove solids (solid metal hydroxides, such as solid nickel hydroxide, solid calcium hydroxide, or solid magnesium hydroxide) from the reactor. Examples of solids handling devices include, but are not limited to, conveyor belts, augers, pumps, chutes, or any other device capable of removing and transporting solids from the reactor. In some embodiments, the solids handling device separates solids and liquids using one or a combination of fluid flow, filtration, sedimentation, centrifugal force, electrophoresis, dielectrophoresis or magnetic separation.

[0180] In some embodiments, the reactor comprises more than one reactor outlet (e.g., at least 1, at least 2, at least 3, at least 4, less than or equal to 5, less than or equal to 4, less than or equal to 3, or less than or equal to 2; combinations of these ranges are also possible). In certain embodiments, the reactor comprises a second outlet.

[0181] In certain embodiments, the second outlet is configured to extract gases (such as CO2, O2, and / or H2). In some cases, the CO2 will be sequestered, used in liquid fuels, used in oxyfuels, used in enhanced oil recovery, used to produce dry ice, and / or used as an ingredient in beverages. In some embodiments, the O2 will be sequestered, used as oxyfuels, used in CCS applications, and / or used in enhanced oil recovery. In certain cases, the H2 will be sequestered and / or used as a fuel (e.g., in a fuel cell and / or to heat the system). In some embodiments, at least a portion (e.g., at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, or all) of the CO2, O2, and / or H2 extracted from the system is fed to a kiln.

[0182] In some embodiments, the reactor includes a third outlet and / or a fourth outlet. In some cases, the second outlet, the third outlet and / or the fourth outlet are configured to extract CO2, O2 and / or H2. For example, in some cases, the second outlet is configured to extract CO2 and O2, while the third outlet is configured to extract H2. In one particular example, the second outlet is configured to extract CO2, the third outlet is configured to extract O2, and the fourth outlet is configured to extract H2.

[0183] According to some embodiments, the reactor further comprises one or more membranes selectively permeable to ions between the first electrode and the second electrode. In certain embodiments, the one or more membranes selectively permeable to ions include two membranes selectively permeable to ions. In certain embodiments, the two membranes selectively permeable to ions are different from each other.

[0184] In some embodiments, the one or more membranes selectively permeable to ions are configured to prevent deposition of solids on the first electrode, to prevent solids from passivating the first electrode, and / or to prevent two different solids from intermixing with each other. According to certain embodiments, the membranes selectively permeable to ions allow the passage of ions while simultaneously limiting (or eliminating) the passage of solids. For example, in some embodiments, metal ions (e.g., Ca 2+ ) are able to pass, while solid metal salts (e.g., solid metal carbonates such as solid CaCO3) or precipitates (e.g., solid metal hydroxides such as solid Ca(OH)2) are restricted (or do not pass at all).

[0185] In some embodiments, a membrane selectively permeable to ions allows the passage of ions but limits (or eliminates) the passage of non-ionic compounds. In certain embodiments, a membrane selectively permeable to ions allows ions to pass at a first rate and non-ionic compounds to pass at a second rate that is slower than the first rate. In some embodiments, a membrane selectively permeable to ions allows the passage of some ions but limits (or eliminates) the passage of other ions. In certain embodiments, a membrane selectively permeable to ions allows some ions to pass at a first rate and other ions to pass at a second rate that is slower than the first rate. In some embodiments, a membrane selectively permeable to ions may allow the passage of some metal ions but limits (or eliminates) the passage of others (or allows some metal ions to pass faster than others), H + Although it may be possible for OH - The passage of is restricted (or eliminated) (or H + OH - (which allows the passage of the OH - Although it may be possible for H + The passage of OH is restricted (or eliminated) - is H+ faster than H), which may allow metal ions to pass through. + and / or OH - The passage of H is restricted (or eliminated) (or metal ions are + and / or OH - faster than H + and / or OH - ions may be allowed to pass, but the passage of metal ions is restricted (or eliminated) (or H + and / or OH - ions can pass through more quickly than metal ions).

[0186] For example, in some embodiments, the membrane that is selectively permeable to ions is OH - Permeable to ions, but not Ca 2+ The membrane has relatively low permeability to ions. On the other hand, the membrane is selectively permeable to ions such as Ca. 2+ Permeable to ions, but not to OH - It is relatively impermeable to ions. In this example, Ca from the first region (e.g., the acidic region) 2+ can diffuse through the membrane selectively permeable to ions into the separation chamber, but cannot diffuse through the membrane selectively permeable to ions into a second region (e.g., an alkaline region). Furthermore, in this example, OH - Ions can diffuse through a membrane that is selectively permeable to the ion into the separation chamber, but cannot diffuse through a membrane that is selectively permeable to the ion. Thus, in this example, Ca 2+ and O.H. -It appears that the Ca(OH) reacts to form solid Ca(OH)2 in the separation chamber and can only prevent solid Ca(OH)2 from forming on the surface of the cathode or anode. Thus, in some embodiments, one or more membranes selectively permeable to ions can prevent solids (e.g., solid metal hydroxides such as solid Ca(OH)2) from precipitating on the first electrode (e.g., the cathode), can prevent solids (e.g., solid metal hydroxides such as solid Ca(OH)2) from passivating the first electrode (e.g., the cathode), and / or can prevent two different solids, i.e., chemical compounds (e.g., metal salts such as solid metal carbonates such as solid calcium carbonate) and precipitates (e.g., solid hydroxides such as solid metal hydroxides such as solid Ca(OH)2) from mixing with each other.

[0187] In certain embodiments, the reactors are directed to the production of calcined or decomposed inorganic or metal salts (e.g., metal carbonates) by electrochemical and chemical means. In some embodiments, the use of such reactors instead of traditional thermal calcinations, which involve heating inorganic or metal salts to decompose them, reduces or avoids the use of fossil fuels for the production of thermal energy and the associated production of greenhouse gases (e.g., CO2) or gases that are air pollutants.

[0188] Certain aspects relate to a system for producing cement. In some embodiments, the system comprises a reactor. In certain embodiments, the reactor comprises any of the reactor embodiments disclosed above or anywhere herein, or a combination thereof.

[0189] In certain embodiments, the system (e.g., any of the systems described herein) comprises a kiln. For example, with reference to FIG. 1F, in some embodiments, the system comprises an electrochemical reactor and kiln 150. Similarly, with reference to FIG. 2D, in certain embodiments, the system comprises an electrochemical reactor and kiln 150. In some embodiments, the kiln comprises a kiln inlet. According to some embodiments, the kiln is attached directly to the reactor and / or apparatus (e.g., an apparatus configured to react an acid and / or base in a precipitation reaction). A kiln (e.g., any of the kilns described herein) may be used in any of the systems described herein.

[0190] According to some embodiments, the kiln is downstream from the reactor, the reactor outlet, and / or the one or more devices. According to certain embodiments, the system further comprises a heater between the reactor, the reactor outlet, and / or the one or more devices, and the kiln inlet. Examples of heaters include devices that heat or dehydrate materials placed therein. In some embodiments, the reactor outlet is attached directly to the kiln inlet.

[0191] As used herein, a direct attachment exists between a first unit and a second unit (and two units are said to be "directly attached" to each other) if the units are connected to each other and the composition of the material transferred between the units does not change substantially when transported from the first unit to the second unit (i.e., the relative abundance of the components does not change by more than 5%). As an illustrative example, a conduit connecting a first unit and a second unit, in which the pressure and temperature of the contents of the conduit are adjusted but the composition of the contents does not change, is said to directly attach the first unit and the second unit. On the other hand, a conduit is not said to directly connect the first unit and the second unit if a separation process and / or a chemical reaction occurs that substantially changes the composition of the contents of the conduit during flow from the first unit to the second unit. In some embodiments, two units that are directly attached to each other are configured such that there is no phase change of the material when transported from the first unit to the second unit.

[0192] In certain embodiments, the kiln inlet is configured to receive at least a portion of the solid calcium hydroxide and / or solid calcium oxide derived from at least a portion of the solid calcium hydroxide. For example, in some embodiments, calcium hydroxide is collected from a reactor, a reactor outlet, and / or more devices, and the reactor, reactor outlet, and / or more devices are directly attached to the kiln inlet, and thus the kiln inlet is configured to receive at least a portion of the solid calcium hydroxide. In certain embodiments, calcium hydroxide is collected from a reactor, a reactor outlet, and / or more devices and transported to the heater. In some embodiments, the heater 103 converts the calcium hydroxide, fully or partially, to calcium oxide. In some embodiments, the kiln inlet is configured to receive at least a portion of the solid calcium hydroxide and / or solid calcium oxide derived from at least a portion of the solid calcium hydroxide from the heater.

[0193] According to some embodiments, the kiln is configured to heat Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (e.g., solid calcium oxide) and / or their reaction products as part of the cement manufacturing process. In some embodiments, heating the Ca(OH)2 and / or lime as part of the cement manufacturing process includes heating the Ca(OH)2 and / or lime with other compounds in the kiln. For example, the Ca(OH)2 and / or lime may be heated with SiO2 or other minerals in the kiln.

[0194] In certain cases, the present systems have a lower net carbon footprint (e.g., at least 10% less, at least 25% less, at least 50% less, at least 75% less, or at least 90% less) than a substantially similar system that uses conventional thermal firing instead of an electrochemical reactor. In some examples, the present systems have a zero net carbon footprint.

[0195] Certain aspects relate to methods of forming precipitates in a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient), according to some embodiments, the methods are carried out in a reactor and / or system, or combinations thereof, as described in connection with any of the embodiments disclosed above or anywhere herein.

[0196] According to some embodiments, the method includes transporting a chemical compound (e.g., a metal salt) to a first region (e.g., an acidic region) of a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In certain embodiments, the metal salt includes a metal carbonate. According to some embodiments, the metal carbonate includes calcium carbonate, magnesium carbonate, and / or nickel carbonate. For example, according to some embodiments, the method includes transporting calcium carbonate to a first region (e.g., an acidic region) of a spatially varying pH gradient.

[0197] According to certain embodiments, chemical compounds (e.g., metal salts) dissolve and / or react in liquids within a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). Non-limiting examples of liquids include non-aqueous or aqueous solutions. Examples of non-aqueous solutions include solutions comprising a non-aqueous solvent and an electrolyte salt, and / or solutions comprising an ionic liquid. Examples of aqueous solutions include solutions comprising water and an electrolyte salt. Examples of electrolyte salts include NaSO4 and NaClO4. In some embodiments, chemical compounds (e.g., metal salts) dissolve and react in liquids within a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). For example, in some embodiments, calcium carbonate dissolves and / or reacts in liquids within a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In some embodiments, calcium carbonate dissolves and reacts in liquids within a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). For example, a chemical compound (e.g., a metal salt) (e.g., calcium carbonate) may be added to a first region (e.g., an acidic region) and the chemical compound (e.g., metal salt) (e.g., calcium carbonate) may be allowed to dissolve to form one or more elements, such as a metal (e.g., Ca 2+ and HCO3 - or Ca 2+ In some embodiments, the one or more elements (e.g., Ca, HCO ... 2+ The element (e.g., a metal such as Ca(OH)2) migrates to a second region (e.g., an alkaline region) where it reacts with hydroxide ions in the second region (e.g., an alkaline region) to form a precipitate (e.g., a metal precipitate such as Ca(OH)2).

[0198] In some embodiments, the first region comprises an acidic region. In certain embodiments, the second region comprises an alkaline region. According to some embodiments, a chemical compound (e.g., a metal salt) dissolves in the acidic region and releases one or more elements (e.g., Ca 2+In other embodiments, the first region comprises an alkaline region. In some embodiments, the second region comprises an acidic region. According to certain embodiments, a chemical compound (e.g., a metal salt) dissolves in the alkaline region and one or more elements (e.g., Ca 2+ Metals such as ZnO react in acidic regions.

[0199] According to some embodiments, the method includes collecting a precipitate from a second region (e.g., an alkaline region) of the spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). In certain embodiments, the precipitate includes a metal precipitate, such as a metal hydroxide. Non-limiting examples of metal hydroxides include nickel hydroxide, calcium hydroxide, and magnesium hydroxide. For example, in the example provided above, one or more elements (e.g., Ca, 2+ The element (e.g., metal, such as Ca(OH)2) migrates to a second region (e.g., an alkaline region) where it reacts with hydroxide ions in the second region (e.g., an alkaline region) to form a precipitate (e.g., a metal precipitate, such as Ca(OH)2). Thus, in some embodiments, the method includes collecting solid calcium hydroxide from an alkaline region of a spatially varying chemical composition gradient (e.g., a spatially varying pH gradient). Non-limiting examples of ways in which one or more elements (e.g., metals) can migrate to the second region (e.g., an alkaline region) include diffusion, convective transport, and / or flow transport.

[0200] According to certain embodiments, the precipitate comprises one or more elements (e.g., metals) derived from chemical compounds (e.g., metal salts) dissolved and / or reacted within the spatially varying chemical composition gradient (e.g., spatially varying pH gradient). In some embodiments, the one or more elements comprise a metal element. Metal, as used herein, refers to a metallic metal or a metal ion. In some embodiments, the precipitate comprises a metal cation derived from a metal salt dissolved and / or reacted within the spatially varying chemical composition gradient (e.g., spatially varying pH gradient), which is ionically bound to an anion within the precipitate. For example, in certain embodiments, solid calcium hydroxide comprises calcium derived from calcium carbonate dissolved and / or reacted within the spatially varying chemical composition gradient (e.g., spatially varying pH gradient).

[0201] According to one particular embodiment, the method is a method for producing cement.

[0202] According to certain embodiments, the method includes heating Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (e.g., solid calcium oxide) and / or their reactant products in a kiln to produce cement. In some embodiments, this includes removing the calcium hydroxide from the reactor and placing it directly in the kiln. Alternatively, in certain embodiments, there is a step between collecting the calcium hydroxide and heating it in the kiln. In some embodiments, a heater converts the calcium hydroxide to its calcium oxide, and then the calcium hydroxide and / or oxide calcium oxide are heated in the kiln. In some embodiments, the heater converts the calcium hydroxide 100% (by weight) to its calcium oxide, and only the calcium oxide is heated in the kiln. In other embodiments, the heater converts 10% or greater, 20% or greater, 30% or greater, 40% or greater, 50% or greater, up to 90%, up to 95%, or up to 99% of calcium hydroxide to calcium oxide. Combinations of these ranges are also possible (e.g., 10% to 100% by weight, inclusive). In some embodiments, both calcium hydroxide and calcium oxide are heated in the kiln. Examples of heaters include devices that heat or dehydrate materials placed therein.

[0203] In some embodiments, heating Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (e.g., solid calcium oxide) and / or their reactant products in a kiln to produce cement includes heating Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (e.g., solid calcium oxide) and / or their reactant products with other compounds in a kiln. For example, Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (e.g., solid calcium oxide) and / or their reactant products may be heated in a kiln with SiO2 or other minerals.

[0204] In certain embodiments, the step of heating the Ca(OH)2 (e.g., solid calcium hydroxide) and / or lime (e.g., solid calcium oxide) and / or their reactant products in a kiln is followed by a next step prior to producing the cement. For example, in certain embodiments, the kiln is followed by a cooling step.

[0205] According to some embodiments, the method is part of a batch process. In certain embodiments, the precipitate (e.g., metal hydroxide, such as Ca(OH)2) is periodically collected from the reactor. According to certain embodiments, the method is performed continuously. In some embodiments, a chemical compound (e.g., a metal salt, such as a metal carbonate, such as CaCO3) is continuously or periodically added at the anode and / or the first zone (e.g., the acid zone). In certain embodiments, the precipitate (e.g., metal hydroxide, such as Ca(OH)2) is continuously or periodically collected. Non-limiting examples of collecting the precipitate (e.g., metal hydroxide, such as Ca(OH)2) include collecting the precipitate by a flow stream and / or allowing it to deposit on a surface from which the precipitate is continuously or periodically collected.

[0206] According to some embodiments, the method produces by-products other than a precipitate. For example, in some embodiments, the method produces by-products other than solid calcium hydroxide and / or solid calcium oxide. In some embodiments, the by-products include CO2, O2, and / or H2. For example, in some embodiments, hydrolysis is carried out in the reactor and the reaction occurring at the cathode converts two H2O molecules and two electrons into H2(g) and two OH -while the reaction occurring at the anode converts two H2O molecules into O2(g), four electrons, and four protons. In certain embodiments, a chemical compound (e.g., a metal salt) (e.g., a metal carbonate such as calcium carbonate) is added to the first region (e.g., an acidic region) and the chemical compound (e.g., a metal salt) (e.g., a metal carbonate such as calcium carbonate) reacts with the protons in the first region (e.g., an acidic region), thus dissolving the chemical compound (e.g., a metal salt) (e.g., a metal carbonate such as calcium carbonate) and forming one or more elements (e.g., metals). In some embodiments, the net reaction between CaCO3 and the two protons is H2O, Ca 2+ and resulting in the formation of CO2(g).

[0207] According to certain embodiments, the method further includes collecting the by-products. For example, in some embodiments, the by-products include CO2, O2, and H2. In certain embodiments, collecting the by-products includes collecting each of CO2, O2, and H2: collecting only CO2; collecting only O2; collecting only H2; collecting CO2 and O2; collecting CO2 and H2; or collecting O2 and H2. For example, in certain embodiments, the by-products include CO2, and recovering the by-products includes sequestering CO2.

[0208] According to some embodiments, the by-products are used as fuel. In some embodiments, H2 can be used as fuel. Non-limiting examples include directly combusting H2 or using H2 with a fuel such as natural gas. In some embodiments, O2 and CO2 are used to support the combustion of a fuel, such as a fossil fuel. In some embodiments, the by-products are used as fuel for a kiln. For example, in some embodiments, O2 and CO2 are fed to a kiln to support the combustion of a fuel, such as a fossil fuel. In certain embodiments, H2, O2, and CO2 are reacted in a fuel cell, such as a solid oxide fuel cell. In certain embodiments, H2 and O2 are reacted in a fuel cell to generate electricity.

[0209] According to some embodiments, the reactors, systems, and methods described herein exhibit one or more beneficial properties and have one or more applications. For example, some embodiments of the reactors, systems, and methods described herein can be used to produce cement (e.g., Portland cement). For example, in some embodiments, the reactor is used in place of calcination in a traditional cement manufacturing process.

[0210] Additionally, certain embodiments of the reactors, systems and methods described herein can be used to produce cement that produces less air pollutants or greenhouse gases, such as CO2, than traditional cement production processes, which involve calcining CaCO3 by thermal means, which accounts for approximately 60% of the CO2 emissions, while approximately 40% of the CO2 emissions come from burning fossil fuels to drive the calcination and sintering processes.

[0211] In some embodiments, Ca(OH)2 produced by the methods, reactors and / or systems described herein can be used to produce CaO for cement manufacturing instead of the conventional calcination of CaCO3 to CaO. The thermal dehydration of Ca(OH)2 to CaO has a minimum energy requirement (71.2 kJ / mol) that is 25% lower than the thermal calcination of CaCO3 to CaO (97.0 kJ / mol).

[0212] According to certain embodiments, the reactor and / or system is powered, in part or in whole, by renewable electricity (eg, solar energy, wind energy, and / or hydroelectric power).

[0213] According to certain embodiments, oxycombustion, improved kiln efficiency, NO x By-products such as CO2, H2 and / or O2 are produced that have numerous potential uses, including flue gas suitable for emissions reduction and / or carbon capture and sequestration (CCS). Thus, in some embodiments, the by-products may be sold or used.

[0214] In one embodiment, the electrolysis-driven chemical reactor comprises an electrolysis cell for the electrolysis of water. In some embodiments, such a cell is configured such that electrolysis produces a high pH at the cathode, where the hydrogen evolution reaction (HER) occurs, producing OH - is produced, creating a low pH at the anode where the oxygen evolution reaction (OER) occurs, producing H + Thus, according to certain embodiments, a pH gradient is generated between the cathode and the anode. In such other electrolysis cells, gradients of other chemical species may be generated depending on the nature of the electrolysis reaction.

[0215] In one embodiment, the pH gradient is used to dissolve metal carbonates at a low pH near the anode, and metal hydroxides precipitate as the metal ions diffuse toward the higher pH environment at the cathode. In some such embodiments, as the metal carbonates dissolve near the anode, CO2 gas is produced and the carbonate metal cations are produced in solution. These are then transported by diffusion or convection or current as required toward the higher pH environment generated by HER at the cathode, according to some such embodiments. According to some embodiments, the metal ions and the OH generated at the cathode are then transported by diffusion or current as required toward the higher pH environment generated by HER at the cathode. - Reaction with the ions results in the precipitation of metal hydroxides. According to some embodiments, electrochemical and chemical reactions occur at each electrode, as well as the overall reaction. Almost any metal carbonate or mixture of metal carbonates can be converted to its hydroxide(s) by such a process, with non-limiting examples of metal carbonates including CaCO3, MgCO3, and NiCO3. In some such embodiments, hydrogen gas is liberated at the cathode and a mixture of oxygen and carbon dioxide gases is liberated at the anode, simultaneously with the production of the metal hydroxide from the starting metal carbonate.

[0216] In one or more embodiments, the reactor is run in batches, whereby the product metal hydroxide is collected periodically. In one or more embodiments, the reactor is run in a continuous manner, where additional metal carbonate is added continuously or periodically at the anode, and precipitated metal hydroxide is continuously or periodically removed from the reaction zone. For example, precipitated metal hydroxide may be removed from the reaction zone using a flow stream and collected, or the precipitate may be allowed to accumulate on a surface that is continuously or periodically removed while the reactor is running continuously.

[0217] In some embodiments, the hydrogen and / or oxygen gas produced by the electrochemical reactor is advantageously used or sold. In some embodiments, the hydrogen and oxygen are reacted in a fuel cell to generate electricity. In some embodiments, the hydrogen is burned as a fuel or as a component of a fuel to heat a reactor or a kiln or furnace.

[0218] In some embodiments, the power to run the electrolysis-driven chemical reactor is generated from renewable sources, including but not limited to solar energy, wind energy, or hydroelectric power.

[0219] In one embodiment, the electrochemically driven chemical reactor is used to decarbonate CaC03 to produce Ca(OH)2 as a precursor for cement production, including Portland cement. It is useful to compare the total energy consumption of both and consider the form of energy consumed and its carbon intensity. For simplicity, assume that the high temperature heat treatment that causes CaO to react with aluminosilicates and other components to form Portland cement is identical for the two processes. Consider the energy consumption for thermal calcination of CaC03 to produce CaO, and the energy consumption for electrochemical decarbonation followed by thermal dehydration of Ca(OH)2 to the same starting temperature of 900C. The energy input per mole to heat a reactant or product to a given temperature is calculated from its heat capacity. The energy per mole to carry out the decomposition reaction is given as the standard free energy of the reaction (i.e., the gas partial pressure is 1 atm).

[0220] In this example, comparing the energy per mole for thermal calcination of CaC03 with the energy per mole for thermal dehydration of Ca(OH)2, the latter has a minimum energy requirement of 25% less, 72.1 kJ / mol versus 97.0 kJ / mol. In this example, the electrochemical process also includes a decarboxylation reaction in which CaC03 is converted to Ca(OH)2 with a standard free energy of 74.3 kJ / mol. This is an additional energy expenditure for the electrochemical process. However, this exemplary process and electrolysis reaction can be powered by electricity derived from low or zero carbon renewable resources with the marginal cost of electricity being near zero.

[0221] In this exemplary process, the electrolysis reaction required to run the reactor requires 237.1 kJ / mole. However, this energy can still be generated first by a low carbon source and then used separately as a value-added product, or can be used to power the cement production process, for example by using a fuel cell to provide the power source, or by a combustion process to produce hydrogen and oxygen that provide the heat of reaction. The energy generated can be used to run an electrolyzer or heat a high temperature kiln.

[0222] In some embodiments, calcium hydroxide, also known as slaked lime, produced herein (e.g., from a precipitation reaction), and / or calcium oxide, which reacts with water to produce slaked lime, may be used in applications including, but not limited to, papermaking, flue gas processing carbon capture, stucco mixes and masonry (including pozzolanic cement), soil stabilization, pH control, water treatment, waste treatment, and sugar refining. The following are non-limiting examples of uses of calcium hydroxide (also known as slaked lime) and / or calcium oxide (also known as lime):

[0223] 1.Metallurgical applications

[0224] a) Iron-based metals In some embodiments, the hydrated lime and / or lime produced by the reactor, system and / or method disclosed herein is used in the production of iron and / or steel. For example, in the production of iron and / or steel, lime can be used as a flux to form a slag that prevents the iron and / or steel from oxidizing and removes impurities such as silica, phosphate, manganese and sulfur. In some cases, hydrated lime (dry or as a slurry) is used as a lubricant for drawing wire or rod from a die in the production of iron and / or steel, as a coating on casting dies to prevent adhesion, and / or as a coating on steel products to prevent corrosion. In some cases, lime or hydrated lime is also used to neutralize acid waste.

[0225] b) Non-ferrous metals In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used in the production of non-ferrous metals, including, but not limited to, copper, mercury, silver, gold, zinc, nickel, lead, aluminum, uranium, magnesium and / or calcium. Lime can be used in some cases as a flux to remove impurities (silica, alumina, phosphates, carbonates, sulfur, sulfates) from the ore. For example, lime and slaked lime can be used in the flotation or recovery of non-ferrous ores. In certain cases, lime acts as a precipitation aid to maintain proper alkalinity and / or remove impurities (such as sulfur and / or silicon). In some examples, slaked lime is used in the smelting and refining of copper, zinc, lead and / or other non-ferrous ores to neutralize sulfur gases and / or prevent the formation of sulfuric acid. In certain examples, lime and / or slaked lime is also used as a coating on metal surfaces to prevent reaction with sulfur species. In certain cases, in aluminum production, lime and / or hydrated lime are used to remove impurities (such as silica and / or carbonate) from bauxite ore and / or to adjust the pH. In some cases, lime is used in cyanide extraction to maintain an alkaline pH for leaching gold, silver and / or nickel. In zinc production, lime is used in certain cases as a reducing agent. In some cases, in calcium metal and / or magnesium metal production, magnesium oxide and / or calcium oxide are reduced at high temperatures to form magnesium metal and / or calcium metal.

[0226] 2. Architecture

[0227] a) Masonry (other than Portland cement) In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to manufacture masonry mortar, plaster, stucco, whitewash, grout, brick, board and / or non-Portland cement. In these applications, in certain embodiments, the lime and / or slaked lime can be mixed with other additives and exposed to carbon dioxide to produce calcium carbonate, the lime and / or slaked lime can react with other additives (such as aluminosilicates) to form cementitious materials, and / or the lime and / or slaked lime can be used as a calcium source. In the examples of mortar, plaster, stucco and whitewash, in some cases the lime and / or slaked lime is mixed with additives and / or aggregates (such as sand) to form a paste / slurry that hardens as the water evaporates and as the lime and / or slaked lime reacts with atmospheric carbon dioxide to form calcium carbonate. In the case of hydraulic pozzolanic cements, in certain cases, lime and / or slaked lime are reacted with aluminates, silicates and / or other pozzolanic materials (e.g., pulverized fuel ash, volcanic ash, blast furnace slag and / or calcined clay) to form a water-based paste / slurry that hardens as insoluble calcium aluminosilicates are formed. In the case of other hydraulic cements, in some instances, lime and / or slaked lime are reacted with a silica source, an alumina source and / or other additives at elevated temperatures to form cementitious compounds, including dicalcium silicate, calcium aluminate, tricalcium silicate and / or monocalcium silicate. In some cases, ash-sand bricks are produced by reacting slaked lime with a silica source (e.g., sand, crushed siliceous stone and / or flint) and / or other additives at the temperatures required to form calcium silicate and / or calcium silicate hydrate. In some cases, lightweight concrete (eg, Aircrete) is produced by reacting lime and / or hydrated lime with reactive silica, aluminum powder, water and / or other additives.The reaction between slaked lime and silicates / aluminates causes the formation of calcium silicates / aluminates and / or calcium silicate hydrates, while the reaction between water, slaked lime and aluminum causes hydrogen bubbles to form in the hardened paste. Water plaster is a white coating made from a suspension of slaked lime, which hardens and hardens as the slaked lime reacts with carbon dioxide from the atmosphere. In some cases, calcium silicate-forming materials (e.g., lime, slaked lime, silica and / or cement) and additives (e.g., cellulose fibers and / or fire retardants) and water are mixed together and cast or pressed into shapes to form calcium silicate board, concrete and other cast calcium silicate products. In some cases, high temperatures are used to react the lime, slaked lime and / or silica and / or hydrate the cement.

[0228] b) Soil stabilization In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to stabilize, harden and / or dry soil. For example, lime and / or slaked lime may be applied to loose or pulverized soil prior to the construction of roads, runways and / or railroad tracks, and / or to stabilize banks and / or slopes. In some cases, when lime is applied to clay soil, a pozzolanic reaction can occur between the clay and lime to produce calcium silicate hydrates and / or calcium aluminate hydrates, which strengthen and / or harden the soil. In certain instances, the lime and / or slaked lime applied to soil can also react with carbon dioxide to produce solid calcium carbonate, which can also strengthen and / or harden the soil. In some cases, lime can also be used to dry wet soil at construction sites, since lime easily reacts with water to form slaked lime.

[0229] c) Asphalt additives and asphalt recycling In some embodiments, the hydrated lime and / or lime produced by the reactor, system and / or method disclosed herein is used to manufacture and / or reuse asphalt. For example, in some cases, hydrated lime is added to hot mix asphalt as an inorganic filler and / or antioxidant and / or to improve resistance to water stripping. In certain cases, hydrated lime can react with aluminosilicates and / or carbon dioxide to create a solid product that improves the bond between the binder and aggregates in asphalt. As an inorganic filler, in some cases, lime can improve the viscosity of the binder, the stiffness of the asphalt, the tensile strength of the asphalt and / or the compressive strength of the asphalt. In certain cases, as a hydraulic binder for roads, lime can harden the binder with reduced moisture sensitivity and / or stripping, so that the lime can resist rutting and / or improve toughness and / or resistance to fracture at low temperatures. In some instances, lime and / or hydrated lime added to recycled asphalt provides greater early strength and / or resistance to moisture damage.

[0230] 3. Waste treatment, water treatment, gas treatment

[0231] a) Gas treatment In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to remove acid gases (such as hydrogen chloride, sulfur dioxide, sulfur trioxide and / or hydrogen fluoride) and / or carbon dioxide from gas mixtures (e.g., flue gas, atmospheric air, storage room air, and / or air in enclosed breathing environments such as submarines). For example, in some cases, the lime and / or hydrated lime is exposed to flue gas, causing a reaction of the lime and / or hydrated lime with components of the flue gas (such as acid gases including hydrogen chloride, sulfur dioxide and / or carbon dioxide) resulting in the formation of non-gaseous calcium compounds (such as calcium chloride, calcium sulfite and / or calcium carbonate). In certain embodiments, the exposure of the gas to hydrated lime is performed by spraying the gas with a solution and / or slurry of hydrated lime and / or by reacting the gas stream with dry lime and / or hydrated lime. In certain embodiments, a gas stream containing the acid gas(es) is first reacted with a solution of an alkali metal hydroxide (e.g., sodium hydroxide and / or potassium hydroxide) to form a soluble intermediate species (such as potassium carbonate) which is subsequently reacted with lime and / or slaked lime to produce a solid calcium species (such as calcium carbonate) to regenerate the original alkali metal hydroxide solution. In some embodiments, the calcium carbonate formed from the reaction of the lime and / or slaked lime with carbon dioxide or alkali carbonate is returned to the reactors, systems and / or methods disclosed herein so that the lime and / or slaked lime can be regenerated and / or the carbon dioxide can be sequestered.

[0232] b) Non-gaseous waste treatment In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to treat wastes such as biological wastes, industrial wastes, wastewater and / or sludge. In some cases, the lime and / or hydrated lime are applied to wastes to create an alkaline environment, which acts to neutralize acidic wastes, inhibit pathogens, repel flies or rodents, control odors, prevent leakage, and / or stabilize and / or precipitate contaminants (such as heavy metals, chromium, copper and / or suspended / dissolved solids) and / or dissolved ions (calcium ions and / or magnesium ions) that cause scaling. In certain examples, lime may be used to dewater oily wastes. In some cases, hydrated lime may be used to precipitate certain chemical species such as phosphates, nitrates and / or sulfur compounds and / or prevent leakage. In certain examples, lime and / or hydrated lime can be used to hasten the decomposition of organic matter by maintaining alkaline conditions that favor hydrolysis.

[0233] c) Water treatment In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to treat water. For example, the lime and / or hydrated lime can be used in some cases to generate an alkaline environment, which acts to disinfect, remove suspended and / or colloidal materials, reduce hardness, adjust pH, precipitate ions that contribute to water hardness, precipitate dissolved metals (such as iron, aluminum, manganese, barium, cadmium, chromium, lead, copper and / or nickel), and / or precipitate other ions (such as fluoride ions, sulfate anions, sulfite anions, phosphate anions and / or nitrate anions).

[0234] 4. Agriculture and Food

[0235] - Agriculture In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used in agriculture. For example, the lime and / or hydrated lime can in some cases be used alone or as an additive in fertilizers to adjust the pH of soil and / or fertilizer mixtures to provide optimal growing conditions and / or improve crop yields.

[0236] - sugar In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to refine sugar. For example, in some cases, the lime and / or slaked lime are used to improve the pH of raw sugar juice, to destroy enzymes in raw sugar juice, and / or to react with inorganic and / or organic species to form precipitates. Excess calcium can be precipitated, in certain instances, with carbon dioxide. In certain cases, the resulting precipitated calcium carbonate can be returned to the reactors, systems and / or methods disclosed herein to regenerate slaked lime.

[0237] - Leather In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to make leather and / or parchment. In the leather manufacturing process, lime is sometimes used to remove hair and / or keratin from the skin, split fibers, and / or remove fat.

[0238] - Glue, gelatin In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to manufacture adhesives and / or gelatin. In some adhesive and / or gelatin manufacturing processes, animal bones and / or skins are soaked in hydrated lime to hydrolyze collagen and other proteins to form a mixture of protein fragments of various molecular weights.

[0239] - Dairy products In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to produce dairy products. In some cases, hydrated lime is used to neutralize the acidity of cream prior to pasteurization. In certain cases, hydrated lime is used to precipitate calcium caseinate from an acidic solution of casein. In some examples, hydrated lime is added to fermented skim milk powder to produce calcium lactate.

[0240] - Fruit Industry In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used in the fruit industry. For example, the slaked lime and / or lime are used in some cases to remove carbon dioxide from the air during fruit storage. In some examples, the slaked lime is used to neutralize citric acid in waste products and to improve the pH of fruit juices.

[0241] - Insecticides / fungicides In some embodiments, the hydrated lime and / or lime produced by the reactor, system and / or method disclosed herein is used as an additive in fungicides and / or insecticides. For example, hydrated lime can be mixed with copper sulfate to form the pesticide tetracopper sulfate. In some cases, lime can also be used as a carrier for other types of pesticides, as its carbonate salt forms a film on the leaf surface to hold the pesticide on the leaf surface. In some examples, hydrated lime is used to control starfish infestations in oyster farms.

[0242] - food additives In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used as food additives. In some cases, the lime and / or hydrated lime can be used as an acidity regulator, an acid cleaner to remove cellulose (e.g., from grains such as corn) and / or to precipitate certain anions (such as carbonate anions) from brines.

[0243] 5.Chemicals In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to manufacture chemicals. For example, the lime and / or hydrated lime may be used as a calcium and / or magnesium source, an alkali, a drying agent, a causticizing agent, a saponifying agent, a binder, a flocculating and / or precipitating agent, a flux, a glass former, a decomposer of organic matter, a lubricant, a filler and / or a hydrolyzing agent, among others.

[0244] a) Inorganic calcium compounds

[0245] - Precipitated calcium carbonate In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to produce precipitated calcium carbonate. In some examples, a solution and / or slurry of hydrated lime and / or a solution of calcium ions are reacted with carbon dioxide and / or an alkali carbonate, resulting in the formation of precipitates of calcium carbonate and / or magnesium carbonate. In certain examples, the precipitated alkali metal carbonate can be used as a filler, reduce shrinkage, improve adhesion, increase density, modify rheology, and / or whiten / brighten plastics (such as PVC and latex), rubber, paper, paints, inks, cosmetics and / or other coatings. The precipitated carbonate can be used as a fire retardant or dusting agent in some cases. In certain cases, precipitated calcium carbonate can be used as an agricultural alkalizing agent, as a preservative, a flour additive, a brewing additive, a digestive aid, and / or an additive for bituminous products, an abrasive (in cleaners, detergents, scouring powders, and / or toothpaste), a dispersant in pesticides, and / or a drying agent.

[0246] - Calcium hypochlorite In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium hypochlorite, a bleaching agent, by reacting chlorine with the lime and / or slaked lime.

[0247] - Calcium carbide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium carbide, a precursor to acetylene, by reacting the lime with carbonaceous materials (e.g., coke) at high temperatures.

[0248] - Calcium phosphate In some embodiments, the slaked lime and / or lime produced by the reactor, system and / or method disclosed herein is used to produce calcium phosphate (monocalcium phosphate, dicalcium phosphate and / or tricalcium phosphate) by reacting phosphoric acid with slaked lime and / or aqueous calcium ions in the appropriate ratio. In some cases, monocalcium phosphate may be used as an additive in self-rising flour, mineral-fortified foods, as a stabilizer in milk products, and / or as a feed additive. In some examples, dicalcium phosphate dihydrate is used in toothpaste, as a mild abrasive, for mineral fortification of foodstuffs, as a pelleting aid, and / or as a thickener. In certain examples, tricalcium phosphate is used in toothpaste and / or as an anti-caking agent in foodstuffs and / or fertilizers.

[0249] - Calcium bromide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium bromide, in some cases by reacting the lime and / or hydrated lime with hydrobromic acid and / or bromine, and a reducing agent (e.g., formic acid and / or formaldehyde).

[0250] - Calcium ferricyanide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium ferricyanide by reacting the lime and / or hydrated lime with hydrogen cyanide in an aqueous solution of ferrous chloride. The calcium ferricyanide can then be converted to alkali metal salts or ferricyanide salts, which are used as pigments and anti-caking agents.

[0251] - Calcium Silicon In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium silicon by reacting lime, quartz and / or carbon-based materials at high temperatures. In some cases, the calcium silicon is used as a deoxidizer, a desulfurizer, and / or to modify non-metallic inclusions in ferrous metals.

[0252] - Calcium dichromate In some embodiments, the hydrated lime and / or lime produced by the reactors, systems, and / or methods disclosed herein is used to produce calcium dichromate by roasting chromate ore with lime.

[0253] - Calcium Tungstate In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium tungstate, which is used in the production of ferrotungsten and / or phosphors for articles such as lasers, fluorescent lights and / or oscilloscopes, by reacting the lime and / or hydrated lime with sodium tungstate.

[0254] b) Organic calcium compounds

[0255] - Calcium Citrate In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium citrate by reacting the lime and / or slaked lime with citric acid. In some cases, the calcium citrate can be reacted with sulfuric acid to regenerate pure citric acid.

[0256] - Calcium soap In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to make calcium soaps by reacting the hydrated lime with aliphatic acids, wax acids, unsaturated carboxylic acids (e.g., oleic acid, linoleic acid, ethylhexanoic acid), naphthenic acids and / or resin acids. In some cases, the calcium soaps are used as lubricants, stabilizers, release agents, waterproofing agents, coatings and / or additives in printing inks.

[0257] - Calcium Lactate In some embodiments, the slaked lime and / or lime produced by the reactor, system and / or method disclosed herein is used to produce calcium lactate by reacting the slaked lime with lactic acid. In certain examples, the lactic acid can be reacted with sulfuric acid in a second step to produce pure lactic acid. In some examples, these chemicals act as coagulants and foaming agents. In some cases, calcium lactate is used as a calcium source and / or buffering agent in pharmaceuticals and / or food products.

[0258] - Calcium Tartrate In some embodiments, the slaked lime and / or lime produced by the reactor, system and / or method disclosed herein is used to produce calcium tartrate by reacting the slaked lime with an alkali hydrogen tartrate. In some cases, the calcium hydrogen tartrate can be reacted with sulfuric acid in a second step to produce pure tartaric acid. In certain examples, tartaric acid is used as an additive in foodstuffs, pharmaceutical preparations, and / or in plaster and / or metal polishing agents.

[0259] c) Inorganic chemicals

[0260] - Aluminum oxide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce aluminum oxide. The lime is used to precipitate impurities (e.g., silicates, carbonates and / or phosphates) from processed bauxite ore in the preparation of aluminum oxide.

[0261] - Alkaline carbonates and bicarbonates In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to produce alkali carbonates and / or bicarbonates from alkali chlorides in the ammonia-soda process. In this process, in some cases, the lime and / or hydrated lime are reacted with ammonium chloride (and / or ammonium chloride, such as isopropylammonium chloride) to regenerate ammonia (and / or amines, such as isopropylamine) after reaction of the ammonia (and / or amines) with the alkali chloride. In some cases, the resulting calcium chloride can be reacted with an alkaline stream from the reactors, systems and / or methods disclosed herein to regenerate the hydrated lime.

[0262] - Strontium Carbonate In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce strontium carbonate. In some examples, the lime and / or hydrated lime is used to carbonate ammonia and regenerate ammonia from ammonium sulfate formed after reaction with strontium sulfate.

[0263] - Calcium Zirconate In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce calcium zirconate. In some cases, the lime and / or hydrated lime is reacted with zircon, ZrSiO4, to produce calcium silicate and calcium zirconate, and to further refine the calcium zirconate.

[0264] - Alkaline hydroxide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce alkali hydroxide from alkali carbonate in a process often referred to as causticizing or recausticizing. In some cases, the hydrated lime is reacted with alkali carbonate to produce alkali hydroxide and calcium carbonate. The process of causticizing alkali carbonate is characteristic of several other processes, including, in some instances, the refining of bauxite ores, the processing of carbonated oils, and the Kraft liquor cycle (where "green liquor" containing sodium carbonate reacts with hydrated lime to form "white liquor" containing sodium hydroxide).

[0265] - Magnesium hydroxide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce magnesium hydroxide. In some cases, when the hydrated lime is added to a solution containing magnesium ions (e.g., seawater and / or brine solutions), the magnesium hydroxide precipitates from the solution.

[0266] d) Organic chemicals

[0267] - Alkene oxide In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to make alkene oxides. In some examples, the lime is used to saponify or dehydrochlorinate propylene chlorohydrin and / or butene chlorohydrin to produce the corresponding oxides. The oxides can then be converted to glycols, in some examples, by acid hydrolysis.

[0268] - Diacetone alcohol In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to produce diacetone alcohol. In some cases, the slaked lime is used as an alkaline catalyst to promote the self-condensation of acetone to form diacetone alcohol, which is used as a solvent for resins and / or as an intermediate in the production of mesityl oxide, methyl isobutyl ketone and / or hexylene glycol.

[0269] - Hydroxypivalic acid neopentyl glycol ester, pentaerythritol In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used as a basic catalyst to make hydroxypivalic acid neopentyl glycol ester and / or pentaerythritol.

[0270] - Anthraquinone dyes and intermediates In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used as a basic reagent to replace sulfonic acid groups with hydroxides in the manufacture of anthraquinone dyes and / or intermediates.

[0271] - Trichloroethylene In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used to remove chlorine from tetrachloroethane to form trichloroethylene.

[0272] 6. Wide range of uses

[0273] - Silica, silicon carbide and zirconia refractories In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used as a binder, cement and / or stabilizer in the manufacture of silica, silicon carbide and / or zirconia refractories.

[0274] - Lime glass In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used as a lime source in the manufacture of soda-lime glass. In some examples, the lime and / or hydrated lime is heated to high temperatures with other raw materials, including additives such as silica, sodium carbonate, and / or alumina and / or magnesium oxide. In some examples, the molten mixture forms glass upon cooling.

[0275] - White earthenware and vitreous enamel In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used to manufacture white ware and / or vitreous enamel. In certain cases, the hydrated lime is blended with clay to act as a flux, a glass former, help bind materials together, and / or enhance the whiteness of the final product.

[0276] - Lubricant for casting and drawing In some embodiments, the hydrated lime and / or lime produced by the reactor, system and / or method disclosed herein is used as a lubricant for casting and / or drawing materials (such as iron, aluminum, copper, steel and / or precious metals). In some examples, calcium-based lubricants are used at high temperatures to prevent metal from sticking to the die. In certain cases, the lubricant can be calcium soap, blends of lime and other substances (including silicate, alumina, carbon, and / or fluxing agents such as fluorspar and / or alkali oxides). Hydrated lime is used as a lubricant carrier in some cases. In certain examples, the hydrated lime bonds to the surface of the wire, increasing the surface roughness and / or improving the adhesion of the drawing compound.

[0277] - Drilling Mud In some embodiments, hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used in drilling mud formulations to maintain high alkalinity and / or to maintain clay in a non-plastic state. Drilling muds can, in some cases, be pumped up hollow drill tubes when drilling rock for oil and gas. In certain instances, the drilling mud carries rock fragments produced by the drill bit to the surface.

[0278] - Oil Additives and Lubricants In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used as oil additives and / or lubricants. In some cases, the lime is reacted with alkyl phenates and / or organic sulfonates to produce calcium soaps, which are blended with other additives to produce oil additives and / or lubricants. In some cases, the lime-based additives prevent sludge buildup and reduce acidity due to combustion products, especially at high temperatures.

[0279] - Pulp and Paper In some embodiments, the slaked lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used in the pulp and / or paper industry. For example, slaked lime is used in the Kraft process to recausticize sodium carbonate to sodium hydroxide. In some cases, calcium carbonate that forms from this reaction can be returned to the reactors, systems and / or methods disclosed herein to regenerate slaked lime. In certain instances, slaked lime can also be used as an alkali source in the sulfite process of pulping to prepare liquor. In certain instances, slaked lime is added to a solution of sulfuric acid to form bisulfite. In some cases, a mixture of sulfuric acid and bisulfite is used to slake pulp. Slaked lime can also be used in certain instances to precipitate calcium lignosulfonate from spent sulfite liquor.

[0280] - Aquarium In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used as a calcium and / or alkalinity source for marine aquariums and / or coral reef growth.

[0281] - Heat storage method In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein is used for thermochemical energy storage (e.g., for self-heating food containers and / or solar thermal storage).

[0282] - Flame retardant In some embodiments, calcium hydroxide and / or magnesium hydroxide produced by the reactors, systems and / or methods disclosed herein are used as flame retardants that are additives to insulated cables and / or plastic insulation.

[0283] - Antimicrobial agents In some embodiments, the hydrated lime and / or lime produced by the reactors, systems and / or methods disclosed herein are used as antimicrobial agents. For example, in some instances, the lime and / or hydrated lime are used to treat disease-infested areas, such as walls, floors, bedding and / or animal housing.

[0284] The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention. EXAMPLES

[0285] Example 1 This example describes operation of the system in a first mode in which the acid and base produced were collected.

[0286] A nearly neutral solution of 1M Na2SO4 was supplied to the anode (made from carbon felt) and cathode (also made from carbon felt) of the flow cell at a rate of 10 mL per minute, and the solution was withdrawn from the anode and cathode. When a voltage of 2.5 V was applied to the cell, the solution leaving the anode had a pH of 1.5 and the solution leaving the cathode had a pH of 12.5.

[0287] Example 2 This example describes operation of the system in a first mode, where the acid and base produced are collected and reacted.

[0288] A hydrolysis reaction is run in an electrochemical cell comprising a first electrode and a second electrode such that base and hydrogen gas are produced at the first electrode (cathode) and acid and oxygen gas are produced at the second electrode (anode). The base is collected from the reactor via a conduit to a first device in fluid communication with the reactor, and the base is stored in the device. The acid is collected from the reactor via a conduit to a second device in fluid communication with the reactor, and the acid is stored in the device.

[0289] If desired, the base is transferred to a third apparatus in fluid communication with the first apparatus, and the acid is transferred to a fourth apparatus in fluid communication with the second apparatus. Then, in the fourth apparatus, the acid is used to dissolve the CaCO3 by chemical dissolution, and the Ca 2+ ions and CO3 2- ions are formed. Then, Ca 2+ The ions are transferred to a third device (which is in fluid communication with a fourth device) where the base is converted to Ca 2+ It can be used in a precipitation reaction with ions to form Ca(OH)2, which can be used in the cement manufacturing process as required, for example using a kiln and / or heater.

[0290] Example 3 This example describes operation of the system in a first mode, in which the produced oxygen and hydrogen gases are delivered for reduction and oxidation, respectively.

[0291] A hydrolysis reaction is run in an electrochemical cell comprising a first electrode and a second electrode such that base and hydrogen gas are produced at the first electrode (cathode) and acid and oxygen gas are produced at the second electrode (anode). Hydrogen gas is transported via a conduit from the cathode to the anode where it is oxidized to produce an acid. The production of acid further reduces the pH at the anode. Oxygen gas is transported via a conduit from the anode to the cathode where it is reduced to produce a base. The production of base further increases the pH at the cathode.

[0292] In some such systems or methods, the acid and base are collected and / or reacted as needed as described in Example 1.

[0293] Example 4 This example describes operation of the system in a first mode, where the oxygen and gases produced can be collected and sold or used, or recombined to form water.

[0294] The hydrolysis reaction is run in an electrochemical cell comprising a first electrode and a second electrode such that base and hydrogen gas are produced at the first electrode (cathode) and acid and oxygen gas are produced at the second electrode (anode). If gas production is undesirable, the hydrogen and oxygen gases can be collected and sold or used, or recombined to form water.

[0295] Example 5 This embodiment describes alternatively operating the system in a first mode and a second mode.

[0296] The system or method of Example 1 is used when electricity costs are low and / or availability is high, but some or all of the acid and base are stored rather than used for chemical dissolution and / or precipitation reactions. When electricity costs are high and / or availability is low, the system is switched to a second mode in which the polarity of the electrodes is opposite to that of Example 1. The stored base from Example 1 is then added to the anode where the base is oxidized to form oxygen gas. The stored acid is then added to the cathode where the acid is reduced to produce hydrogen gas. The hydrogen and oxygen gases can be collected and sold or used as desired.

[0297] Example 6 This example describes the operation of a system with two reactors to generate an acid and a base that can be used for chemical dissolution and / or precipitation reactions.

[0298] A system is operated that includes two reactors in fluid communication. The first reactor produces a base, a dihalide (e.g., Cl2) and hydrogen gas. The first reactor and the second reactor are in fluid communication, and the hydrogen gas and dihalide produced in the first reactor are transported to the second reactor. Water is also added to the second reactor, and the second reactor produces an acid (e.g., HCl).

[0299] A base is collected from a first reactor with a first device, and an acid is collected from a second reactor with a second device. In the second device, solid CaCO3 is converted to Ca 2+ and CO3 2- The second device is in fluid communication with the first device and is adapted to dissolve the Ca ions from the second device using an acid for chemical dissolution, such as chemical dissolution into Ca ions. 2+ The ions are transported to a first device, where Ca 2+ The ions react with a base in a precipitation reaction to form Ca(OH)2. The Ca(OH)2 can be used in the cement manufacturing process as needed, for example using a kiln and / or heater.

[0300] While several embodiments of the invention are described and illustrated herein, those skilled in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more advantages described herein, and each such variation and / or modification is deemed to be within the scope of the invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials and configurations described herein are intended to be exemplary, and that the actual parameters, dimensions, materials and / or configurations will depend on the particular application or applications for which the teachings of the invention are used. Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments of the invention described herein. It should therefore be understood that the foregoing embodiments are presented by way of example only, and that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material and / or method described herein. Furthermore, any combination of two or more such features, systems, articles, materials and / or methods is included within the scope of the present invention, if such features, systems, articles, materials and / or methods are not mutually inconsistent.

[0301] The indefinite articles "a" and "an," as used in the specification and claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0302] The term "and / or" as used herein and in the claims should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Unless expressly indicated to the contrary, other elements than those specifically identified by the "and / or" clause may be present as needed, whether related or unrelated to the elements specifically identified. Thus, as a non-limiting example, a reference to "A and / or B", when used in conjunction with open-ended language such as "comprising", can refer to, in one embodiment, A without B (optionally including elements other than B); in another embodiment, B without A (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements), etc.

[0303] As used herein and in the claims, "or" should be understood to have the same meaning as "and / or" defined above. For example, when separating items in a list, "or" or "and / or" shall be interpreted as inclusive, i.e., including at least one, but including more than one number or list of elements, and additional unlisted items as appropriate. Only terms clearly indicated to the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or," as used herein, shall be interpreted to indicate exclusive alternatives (i.e., "one or the other, but not both") only when followed by a term of exclusivity, such as "either," "one of," "only one of," or "exactly one of." "Consisting essentially of," when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0304] As used herein and in the claims, the phrase "at least one" referring to a list of one or more elements should be understood to mean at least one element selected from any one or more of the elements in the list of elements, including, but not necessarily, at least one of every element specifically listed in the list of elements, and not excluding any combination of elements in the list of elements. This definition also allows for elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, optionally present, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B" or, equivalently, "at least one of A and / or B") refers, in one embodiment, to at least one A, optionally including two or more, and no B (and optionally including elements other than B); in another embodiment, to at least one B, optionally including two or more, and no A (and optionally including elements other than A); and in yet another embodiment, to at least one A, optionally including two or more, and at least one B (and optionally including other elements).

[0305] In the claims and in the above specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," and the like, are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03. In one embodiment, for example, the following items are provided: (Item 1) Operating the reactor in a first mode A method comprising: The first mode is Producing a base from a first electrode; generating an acid in the reactor from a second electrode electrochemically connected to the first electrode; and collecting said acid and / or base. A method comprising: (Item 2) 2. The method of claim 1, further comprising reacting the collected acid and / or base in a chemical dissolution and / or precipitation reaction. (Item 3) Operating the reactor in a first mode A method comprising: The first mode is Producing a base from a first electrode; generating an acid in the reactor from a second electrode electrochemically connected to the first electrode; collecting the acid and / or base; and reacting said collected acid and / or base in a chemical dissolution and / or precipitation reaction; A method comprising: (Item 4) 4. The method of any one of claims 1 to 3, wherein the first mode includes producing oxygen gas from the second electrode. (Item 5) 5. The method of any one of claims 1 to 4, wherein the first mode includes producing hydrogen gas from the first electrode. (Item 6) Operating the reactor in a first mode A method comprising: The first mode is producing a base and hydrogen gas from the first electrode; generating acid and oxygen gas in the reactor from a second electrode electrochemically connected to the first electrode; and allowing the oxygen gas to diffuse and / or be transported to the first electrode and / or allowing the hydrogen gas to diffuse and / or be transported to the second electrode; and Allowing the oxygen gas to be reduced by the first electrode, and / or allowing the hydrogen gas to be oxidized by the second electrode. A method comprising: (Item 7) 7. The method of claim 6, further comprising collecting the acid and / or base. (Item 8) 8. The method according to any one of items 6 to 7, further comprising reacting the collected acid and / or base in a chemical dissolution and / or precipitation reaction. (Item 9) 9. The method of any one of items 4 to 8, wherein the producing an acid from the second electrode and producing oxygen gas from the second electrode comprises oxidizing water by the second electrode to produce oxygen gas and an acid. (Item 10) 10. The method of any one of items 5 to 9, wherein the producing a base from the first electrode and producing hydrogen gas from the first electrode comprises reducing water by the first electrode to produce hydrogen gas and a base. (Item 11) 20. The method of any one of the preceding claims, further comprising collecting the acid. (Item 12) 2. The method of any one of the preceding claims, further comprising collecting the base. (Item 13) 2. The method of any one of the preceding claims, comprising reacting the collected acid by chemical dissolution. (Item 14) 2. The method of any one of the preceding claims, comprising reacting the collected base in a precipitation reaction. (Item 15) 2. The method of any one of the preceding claims, further comprising a step of storing the acid and / or base. (Item 16) 2. The method of any one of the preceding claims, comprising storing the acid. (Item 17) 2. The method of any one of the preceding claims, comprising storing the base. (Item 18) 2. The method of claim 1, further comprising operating the reactor in a second mode, wherein the polarity of the reactor is reversed in the second mode compared to the polarity of the reactor in the first mode. (Item 19) 19. The method of claim 18, wherein the cost of electricity to operate the reactor in the first mode is a first cost, the availability of electricity to operate the reactor in the first mode is a first availability, the cost of electricity to operate the reactor in the second mode is a second cost, the availability of electricity to operate the reactor in the second mode is a second availability, and the second cost is higher than the first cost and / or the first availability is higher than the second availability. (Item 20) 20. The method of any one of items 18 to 19, wherein the second mode comprises adding the stored base to the reactor adjacent the second electrode. (Item 21) 21. The method of any one of items 18 to 20, wherein the second mode comprises oxidizing the stored base in the vicinity of the second electrode to produce oxygen gas. (Item 22) 22. The method of any one of claims 18 to 21, wherein the second mode comprises adding the stored acid to the reactor adjacent the first electrode. (Item 23) 23. The method of any one of claims 18 to 22, wherein the second mode comprises reducing the stored acid in the vicinity of the first electrode to produce hydrogen gas. (Item 24) 24. The method of any one of items 5 to 23, comprising oxidizing the hydrogen gas by the second electrode. (Item 25) 25. The method of any one of items 5 to 24, comprising oxidizing the hydrogen gas by the second electrode to produce an acid. (Item 26) 26. The method of any one of items 5 to 25, wherein the hydrogen gas is allowed to diffuse from the vicinity of the first electrode to the vicinity of the second electrode. (Item 27) 27. The method of any one of items 5 to 26, wherein the hydrogen gas is transported from a vicinity of the first electrode to a vicinity of the second electrode. (Item 28) 28. The method of any one of items 1 to 3, 5 and 9 to 27, wherein the method does not produce oxygen gas. (Item 29) 2. The method of any one of the preceding claims, wherein the method produces no net hydrogen gas. (Item 30) 30. The method of any one of items 4 to 27 and 29, comprising reducing the oxygen gas by the first electrode. (Item 31) 31. The method of any one of items 4 to 27 and 29 to 30, comprising reducing the oxygen gas by the first electrode to produce a base. (Item 32) 32. The method of any one of items 4 to 27 and 29 to 31, wherein the oxygen gas is allowed to diffuse from the vicinity of the second electrode to the vicinity of the first electrode. (Item 33) 33. The method of any one of items 4 to 27 and 29 to 32, wherein the oxygen gas is transported from the vicinity of the second electrode to the vicinity of the first electrode. (Item 34) 34. The method of any one of items 1 to 4 and 9 to 33, wherein the method does not produce hydrogen gas. (Item 35) 2. The method of any one of the preceding claims, wherein the method produces no net oxygen gas. (Item 36) 36. The method according to any one of items 2 to 5 and 8 to 35, wherein said chemical dissolution comprises chemical dissolution of a metal, a metal alloy, a metalloid, a metal salt, a metal oxide and / or a silicate. (Item 37) 37. The method of claim 36, wherein the metals and / or metal alloys comprise iron, iron alloys, stainless steel, non-ferrous metals, non-ferrous alloys, aluminum, brass, bronze, copper, zinc, tin and / or coin alloys. (Item 38) 38. The method according to any one of items 36 to 37, wherein the metal oxide comprises calcium oxide, magnesium oxide, strontium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, cadmium oxide, lead oxide, silicon dioxide and / or aluminum oxide. (Item 39) 39. The method of any one of items 36 to 38, wherein the metal salt comprises a metal carbonate. (Item 40) 40. The method of claim 39, wherein the metal carbonate comprises calcium carbonate, magnesium carbonate, barium carbonate, strontium carbonate, manganese carbonate, iron carbonate, cobalt carbonate, zinc carbonate, cadmium carbonate, lead carbonate and / or nickel carbonate. (Item 41) 36. The method of any one of items 2 to 5 and 8 to 35, wherein the precipitation reaction comprises precipitating a metal hydroxide. (Item 42) 42. The method of claim 41, wherein the metal hydroxide comprises calcium hydroxide, magnesium hydroxide, barium hydroxide, strontium hydroxide, manganese hydroxide, iron hydroxide, cobalt hydroxide, zinc hydroxide, cadmium hydroxide, lead hydroxide and / or nickel hydroxide. (Item 43) 2. The method of any one of the preceding claims, wherein the acid has a concentration greater than or equal to 0.00001M. (Item 44) 2. The method of any one of the preceding claims, wherein the acid has a concentration greater than or equal to 1 M. (Item 45) 2. The method of any one of the preceding claims, wherein the acid has a concentration less than or equal to 10 M. (Item 46) 2. The method of any one of the preceding claims, wherein the base has a concentration greater than or equal to 0.00001M. (Item 47) 2. The method of any one of the preceding claims, wherein the base has a concentration greater than or equal to 1 M. (Item 48) 2. The method of any one of the preceding claims, wherein the base has a concentration less than or equal to 10 M. (Item 49) 2. The method of claim 1, wherein the pH in the vicinity of the second electrode is less than or equal to 6. (Item 50) 2. The method of any one of the preceding claims, wherein the pH in the vicinity of the first electrode is greater than or equal to 8. (Item 51) 2. The method of claim 1, wherein the Nernst potential at the second electrode is greater than or equal to −0.4 V versus a standard hydrogen electrode. (Item 52) 2. The method of claim 1, wherein the Nernst potential at the second electrode is greater than or equal to 0.8 V versus a standard hydrogen electrode. (Item 53) 2. The method of any one of the preceding claims, wherein the Nernst potential at the first electrode is less than or equal to 0.8 V versus a standard hydrogen electrode. (Item 54) 2. The method of any one of the preceding claims, wherein the Nernst potential at the first electrode is less than or equal to −0.4 V versus a standard hydrogen electrode. (Item 55) 55. The method of any one of items 2 to 5 and 8 to 54, wherein the step of operating the reactor in a first mode is intermittent while the step of reacting the collected acid and / or base in a chemical dissolution and / or precipitation reaction is continuous. (Item 56) 20. The method of any one of the preceding claims, comprising adding a nearly neutral input solution to the reactor. (Item 57) 57. The method of claim 56, wherein the approximately neutral input solution comprises a salt. (Item 58) 58. The method of claim 57, wherein the salt comprises an alkali sulfate, an alkali chlorate, an alkali halide, an alkali nitrate, an alkali perchlorate, an alkali acetate, an alkali nitrite and / or an alkali trifluoromethanesulfonate. (Item 59) 2. The method of any one of the preceding claims, comprising reacting the collected base by chemical dissolution. (Item 60) 20. The method of any one of the preceding claims, comprising reacting the collected acid in a precipitation reaction. (Item 61) A first electrode, a second electrode electrochemically connected to the first electrode; and a device configured to collect an acidic product proximate the second electrode and / or a basic product proximate the first electrode; A system comprising: (Item 62) A first electrode, a second electrode electrochemically connected to the first electrode; a first device configured to collect an acidic product proximate the second electrode and / or a basic product proximate the first electrode; and a second device configured to react the collected acidic product and / or the collected basic product. A system comprising: (Item 63) 63. The system of any one of claims 61 to 62, wherein the first electrode is configured to generate a base and / or hydrogen gas. (Item 64) 64. The system of any one of claims 61 to 63, wherein the second electrode is configured to generate acid and / or oxygen gas. (Item 65) 65. The system of any one of claims 61 to 64, wherein the system is configured to allow oxygen gas to diffuse and / or be transported to the first electrode and / or allow hydrogen gas to diffuse and / or be transported to the second electrode. (Item 66) 66. The system of any one of claims 61 to 65, wherein the system is configured to allow the oxygen gas to be reduced by the first electrode and / or allow the hydrogen gas to be oxidized by the second electrode. (Item 67) a first electrode configured to generate a base and hydrogen gas; and a second electrode in electrochemical communication with the first electrode, the second electrode configured to generate acid and oxygen gas; A system comprising: the system is configured to allow oxygen gas to diffuse and / or be transported to the first electrode and / or allow hydrogen gas to diffuse and / or be transported to the second electrode; and the system is configured to allow the oxygen gas to be reduced by the first electrode and / or the hydrogen gas to be oxidized by the second electrode; system. (Item 68) Item 68. The system of item 67, further comprising a device configured to collect an acidic product proximate the second electrode and / or a basic product proximate the first electrode. (Item 69) Item 69. The system of any one of items 61 to 68, further comprising a separator configured to allow oxygen gas produced at the second electrode to diffuse to the first electrode and / or to allow hydrogen gas produced at the first electrode to diffuse to the second electrode. (Item 70) 70. The system of any one of items 61, 63-66 and 68-69, further comprising a second device configured to react the collected acidic product and / or the collected basic product in a chemical dissolution and / or precipitation reaction. (Item 71) 71. The system of any one of items 62 to 66 and 70, wherein the second device is configured to react the collected acidic output and / or the collected basic output by chemical dissolution. (Item 72) 72. The system of any one of items 62 to 66 and 70 to 71, wherein the second device is configured to react the collected acidic product and / or the collected basic product in a precipitation reaction. (Item 73) 73. The system of any one of items 61-66 and 69-72, wherein the second electrode is configured to generate an acid. (Item 74) 74. The system of any one of items 61-66 and 69-73, wherein the second electrode is configured to generate oxygen gas. (Item 75) 75. The system of any one of items 61-66 and 69-74, wherein the first electrode is configured to generate a base. (Item 76) 76. The system of any one of items 61-66 and 69-75, wherein the first electrode is configured to produce hydrogen gas. (Item 77) 77. The system of any one of claims 64 to 76, wherein the system is configured to allow oxygen gas to diffuse to the first electrode. (Item 78) 78. The system of any one of claims 63 to 77, wherein the system is configured to allow hydrogen gas to diffuse to the second electrode. (Item 79) 79. The system of any one of claims 64 to 78, wherein the system is configured to allow the oxygen gas to be reduced by the first electrode. (Item 80) 80. The system of any one of claims 63 to 79, wherein the system is configured to allow the hydrogen gas to be oxidized by the second electrode. (Item 81) 81. The system of any one of claims 61 to 80, wherein the device is configured to collect the acid output proximate the second electrode. (Item 82) 82. The system of any one of claims 61 to 81, wherein the device is configured to collect the basic product in the vicinity of the first electrode. (Item 83) 83. The system of any one of items 61 to 82, comprising a device configured to store the acid and / or base. (Item 84) 84. The system of any one of claims 61 to 83, comprising a device configured to store the acid. (Item 85) 85. The system of any one of items 61 to 84, comprising a device configured to store the base. (Item 86) 86. The system of any one of claims 61 to 85, configured such that a base can be added in the vicinity of the second electrode. (Item 87) 87. The system of any one of claims 61 to 86, wherein the system is configured to oxidize a base by the second electrode to produce oxygen gas. (Item 88) 88. The system of any one of claims 61 to 87, wherein the system is configured such that an acid can be added in the vicinity of the first electrode. (Item 89) 89. The system of any one of claims 61 to 88, wherein the system is configured to reduce an acid by the second electrode to produce hydrogen gas. (Item 90) 90. The system of any one of claims 63 to 89, wherein the system is configured to oxidize the hydrogen gas by the second electrode to produce an acid. (Item 91) 91. The system of any one of claims 63 to 90, wherein the system is configured to enable transport of the hydrogen gas from a vicinity of the first electrode to a vicinity of the second electrode. (Item 92) 92. The system of any one of items 61 to 66, 69 to 73, 75 to 86 and 88 to 91, wherein the system is configured not to generate oxygen gas. (Item 93) 93. The system of any one of claims 61 to 92, wherein the system is configured to produce no net hydrogen gas. (Item 94) 94. The system of any one of items 64 to 91 and 93, wherein the system is configured to reduce the oxygen gas by the first electrode to produce a base. (Item 95) 95. The system of any one of items 64 to 91 and 93 to 94, wherein the system is configured to enable transport of the oxygen gas from the vicinity of the second electrode to the vicinity of the first electrode. (Item 96) 96. The system of any one of items 61 to 66, 69 to 75, 77 to 88 and 90 to 95, wherein the system is configured not to produce hydrogen gas. (Item 97) 97. The system of any one of claims 61 to 96, wherein the system is configured to produce no net oxygen gas. (Item 98) generating a base and a dihalide in a first reactor; generating acid in a second reactor; collecting the acid; collecting the base; performing chemical dissolution using said acid and / or base; and carrying out a precipitation reaction using said acid and / or base. The method includes: (Item 99) Item 99. The method of item 98, comprising producing hydrogen gas in the first reactor. (Item 100) 100. The method of any one of items 98 to 99, comprising providing a neutral pH alkali halide by-product from the precipitation reaction to the first reactor. (Item 101) 101. The method of any one of items 98 to 100, comprising a step of storing the acid and / or the base. (Item 102) 102. The method according to any one of items 98 to 101, wherein the chemical dissolution comprises chemical dissolution of a metal, a metal alloy, a metalloid, a metal salt, a metal oxide and / or a silicate. (Item 103) 103. The method of claim 102, wherein the metals and / or metal alloys comprise iron, iron alloys, stainless steel, non-ferrous metals, non-ferrous alloys, aluminum, brass, bronze, copper, zinc, tin and / or coin alloys. (Item 104) 104. The method according to any one of items 102 to 103, wherein the metal oxide comprises calcium oxide, magnesium oxide, strontium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, cadmium oxide, lead oxide, silicon dioxide and / or aluminum oxide. (Item 105) 105. The method of any one of items 102 to 104, wherein the metal salt comprises a metal carbonate. (Item 106) 106. The method of claim 105, wherein the metal carbonate comprises calcium carbonate, magnesium carbonate, barium carbonate, strontium carbonate, manganese carbonate, iron carbonate, cobalt carbonate, zinc carbonate, cadmium carbonate, lead carbonate and / or nickel carbonate. (Item 107) 107. The method of any one of claims 98 to 106, wherein the precipitation reaction comprises precipitating a metal hydroxide. (Item 108) 108. The method of claim 107, wherein the metal hydroxide comprises calcium hydroxide, magnesium hydroxide, barium hydroxide, strontium hydroxide, manganese hydroxide, iron hydroxide, cobalt hydroxide, zinc hydroxide, cadmium hydroxide, lead hydroxide and / or nickel hydroxide. (Item 109) 109. The method according to any one of items 98 to 108, wherein the acid has a concentration greater than or equal to 0.1 M. (Item 110) 100. The method according to any one of items 98 to 109, wherein the acid has a concentration greater than or equal to 1 M. (Item 111) 111. The method according to any one of items 98 to 110, wherein the acid has a concentration less than or equal to 12M. (Item 112) 112. The method according to any one of items 98 to 111, wherein the base has a concentration greater than or equal to 0.1 M. (Item 113) 113. The method according to any one of items 98 to 112, wherein the base has a concentration greater than or equal to 1 M. (Item 114) 114. The method according to any one of items 98 to 113, wherein the base has a concentration less than or equal to 25M. (Item 115) 115. The method according to any one of items 98 to 114, wherein the pH in the vicinity of the second reactor is lower than or equal to 6. (Item 116) 116. The method according to any one of items 98 to 115, wherein the pH in the vicinity of the first reactor is greater than or equal to 8. (Item 117) 117. The method of any one of items 98 to 116, wherein the first reactor comprises a second electrode, and the Nernst potential at the second electrode is greater than or equal to 1.36 V versus a standard hydrogen electrode. (Item 118) 118. The method of any one of items 98 to 117, wherein the first reactor comprises a second electrode and the dihalide is generated by the second electrode. (Item 119) 119. The method of any one of items 98 to 118, wherein the first reactor comprises a first electrode, and the Nernst potential at the first electrode is less than or equal to 0.8 V versus a standard hydrogen electrode. (Item 120) 119. The method of any one of items 98 to 118, wherein the first reactor comprises a first electrode, and the Nernst potential at the first electrode is less than or equal to 0.4 V versus a standard hydrogen electrode. (Item 121) 119. The method of any one of items 98 to 118, wherein the first reactor comprises a first electrode, and the Nernst potential at the first electrode is less than or equal to −0.41 V versus a standard hydrogen electrode. (Item 122) 119. The method of any one of items 98 to 118, wherein the first reactor comprises a first electrode, and the Nernst potential at the first electrode is less than or equal to −0.82 V versus a standard hydrogen electrode. (Item 123) 123. The method of any one of claims 98 to 122, wherein the first reactor comprises a first electrode and the base is generated from the first electrode. (Item 124) 124. The method of any one of items 98 to 123, wherein the second reactor is a chemical reactor or a fuel cell. (Item 125) The second reactor is H 2 / Cl 2 125. The method of any one of items 98 to 124, which is a fuel cell. (Item 126) 126. The method of any one of items 98 to 125, comprising performing the chemical dissolution with an acid. (Item 127) 127. The method of any one of items 98 to 126, comprising performing the chemical dissolution using a base. (Item 128) 128. The method of any one of items 98 to 127, comprising carrying out the precipitation reaction with an acid. (Item 129) 129. The method of any one of items 98 to 128, comprising carrying out the precipitation reaction with a base. (Item 130) a first reactor configured to produce a base, a dihalide, and hydrogen gas; a second reactor configured to produce acid; a first device configured to collect the acid proximate the second reactor and perform a chemical dissolution and / or precipitation reaction with the acid; and a second apparatus configured to collect the base proximate the first reactor and perform a chemical dissolution and / or precipitation reaction with the base. A system comprising: (Item 131) Item 131. The system of item 130, wherein the system is configured to supply a neutral pH alkali halide by-product from the precipitation reaction to the first reactor. (Item 132) 132. The system of any one of items 130 to 131, wherein the system is configured to store the acid and / or the base. (Item 133) 133. The system of any one of claims 130 to 132, wherein the chemical dissolution comprises chemical dissolution of a metal, a metal alloy, a metalloid, a metal salt, a metal oxide and / or a silicate. (Item 134) 134. The method of claim 133, wherein the metals and / or metal alloys comprise iron, iron alloys, stainless steel, non-ferrous metals, non-ferrous alloys, aluminum, brass, bronze, copper, zinc, tin and / or coin alloys. (Item 135) 135. The method according to any one of items 133 to 134, wherein the metal oxide comprises calcium oxide, magnesium oxide, strontium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, cadmium oxide, lead oxide, silicon dioxide and / or aluminium oxide. (Item 136) 136. The method of any one of items 133 to 135, wherein the metal salt comprises a metal carbonate. (Item 137) Item 137. The system of item 136, wherein the metal carbonate comprises calcium carbonate, magnesium carbonate, barium carbonate, strontium carbonate, manganese carbonate, iron carbonate, cobalt carbonate, zinc carbonate, cadmium carbonate, lead carbonate, and / or nickel carbonate. (Item 138) 138. The system of any one of claims 130 to 137, wherein the precipitation reaction comprises precipitating a metal hydroxide. (Item 139) Item 139. The system of item 138, wherein the metal hydroxide comprises calcium hydroxide, magnesium hydroxide, barium hydroxide, strontium hydroxide, manganese hydroxide, iron hydroxide, cobalt hydroxide, zinc hydroxide, cadmium hydroxide, lead hydroxide, and / or nickel hydroxide. (Item 140) 140. The system according to any one of items 130 to 139, wherein the acid has a concentration greater than or equal to 0.1 M. (Item 141) 141. The system according to any one of items 130 to 140, wherein the acid has a concentration greater than or equal to 1 M. (Item 142) 142. The system according to any one of items 130 to 141, wherein the acid has a concentration less than or equal to 12M. (Item 143) 143. The system according to any one of items 130 to 142, wherein the base has a concentration greater than or equal to 0.1 M. (Item 144) 144. The system according to any one of items 130 to 143, wherein the base has a concentration greater than or equal to 1 M. (Item 145) 145. The system according to any one of items 130 to 144, wherein the base has a concentration less than or equal to 25M. (Item 146) 146. The system of any one of claims 130 to 145, wherein the first device is configured to perform the chemical dissolution using an acid. (Item 147) 147. The system of any one of claims 130 to 146, wherein the first device is configured to carry out the precipitation reaction using the acid. (Item 148) 148. The system of any one of claims 130 to 147, wherein the second device is configured to perform the chemical dissolution using the base. (Item 149) 149. The system of any one of claims 130 to 148, wherein the second device is configured to carry out the precipitation reaction using the base.

Claims

1. generating an acid and a base by electrolysis; dissolving material in said acid in a region of the reactor having a pH of 6 or less to produce dissolved one or more elements including calcium ions, said material including calcium and silicates; forming at least one precipitate and by-product comprising calcium hydroxide from one or more of said dissolved one or more elements in a region of the reactor having a pH of 10 or greater; collecting the by-products; and mixing said at least one precipitate with a reactive silicate to form a cement. A method comprising:

2. 10. The method of claim 1, wherein the acid and base are stored prior to being used in the dissolution and / or precipitation reactions.

3. 10. The method of claim 1, wherein the acid and base are generated in a reactor system, while the dissolution and precipitation occur in a separate reactor or reactor system.

4. The step of dissolving the material in the acid and base to produce one or more dissolved elements comprises producing CO from the dissolution of carbonates in the acid. ２ The method of claim 1 , further comprising the step of recovering the

5. 2. The method of claim 1 , wherein forming at least one precipitate from one or more of the dissolved one or more elements comprises using the base in a precipitation reaction with one or more of the dissolved one or more elements.

6. The acid and base are at least partially forming a dihalide in a first reactor, preferably the dihalide being Cl ２ and reacting said dihalide in a second reactor. The method of claim 1 , further comprising the step of generating by:

7. forming the dihalide in the first reactor comprises, at least in part, forming the dihalide and hydrogen gas by electrolysis; reacting the dihalide in the second reactor comprises, at least in part, reacting the dihalide with the hydrogen gas to form a hydrogen halide. The method according to claim 6.

8. A system for carrying out the method of any one of claims 1 to 7.

9. A method according to any one of claims 1 to 7, further comprising a step of forming a building material comprising the cement.

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