Systems and methods for corrosion control

Abstract

The present disclosure provides systems and methods of mitigating and controlling corrosion in any industrial process utilizing molten salts. The system may comprise (i) a first conduit comprised of a first material and configured to receive a molten salt stream at a first temperature, and (ii) a second conduit comprised of a second material fluidically connected to the first conduit and configured to receive the molten salt stream at a higher second temperature. A first corrosion product may be formed in the first conduit and a second corrosion product may be formed in the second conduit. A concentration of the second corrosion product may be less than or equal to a concentration of the first corrosion product.

Description

[0001] Attorney Docket No. 64117-709601

[0002] SYSTEMS AND METHODS FOR CORROSION CONTROL

[0003] CROSS-REFERENCE

[0004]

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 779,031, filed March 27, 2025, which is entirely incorporated herein by reference.

[0005] BACKGROUND

[0006]

[0002] In addition to their high temperatures, molten salts present a unique challenge due to their high solubility of oxidized metals, resulting in substantial corrosion which can lead to clogging and fouling of equipment. Corrosion mitigation in molten salt systems may involve purification operations designed to remove oxidative species from the molten salt. However, for systems that expect continuous streams of oxidative species outside of the initial salt load, purifications operations offer marginal benefit and can be costly and difficult to implement. As an alternative to purification, some methods utilize in-situ reduction of the corrosive material (an oxidative species) by sparging with a reducing gas stream, insertion of a reducing metal, and / or the use of a soluble buffering species that has two oxidation states.

[0007]

[0003] However, online redox control presents operational challenges associated with increased system complexity and handling concerns. As an alternative to chemical mechanisms, physical barriers have also been explored. Physical barriers can be challenging to implement in complex geometries, with many cladding techniques requiring line of sight access to the surface, or active cooling of the opposing side in the case of freeze walls. Claddings are also prone to single point failures, with cracks or defects in the surface negating much of the benefit. Accordingly, understanding and mitigating corrosion in molten salts is of utmost importance for the economic viability of industrial applications that look to employ them.

[0008] SUMMARY

[0009]

[0004] Described herein are systems and methods of mitigating and controlling corrosion in any industrial process utilizing molten salts.

[0010]

[0005] In one aspect, disclosed herein is a system. In some embodiments, the system comprises a first conduit comprised of a first material. In some embodiments, the first conduit is configured to receive a molten salt stream at a first temperature. In some embodiments, the molten salt stream comprises an oxidizing species. In some embodiments, the systemAttorney Docket No. 64117-709601

[0011] comprises a second conduit comprised of a second material fluidically connected to the first conduit. In some embodiments, the second conduit is configured to receive the molten salt stream at a second temperature. In some embodiments, the second temperature is higher than the first temperature. In some embodiments, a first corrosion product is formed in the first conduit. In some embodiments, the first corrosion product comprises the oxidizing species and the first material. In some embodiments, a second corrosion product is formed in the second conduit. In some embodiments, the second corrosion product comprises the oxidizing species and the second material. In some embodiments, a concentration of the second corrosion product is less than or equal to a concentration of the first corrosion product.

[0012]

[0006] In some embodiments, the oxidizing species comprises carbonates, oxides, metal oxides, peroxides, or any combination thereof. In some embodiments, the first temperature is from about 300 °C to about 700 °C. In some embodiments, the first temperature is from about 400 °C to about 700 °C. In some embodiments, the second temperature is from about 500 °C to about 900 °C. In some embodiments, the second temperature is from about 600 °C to about 900 °C. In some embodiments, the first material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof. In some embodiments, the second material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

[0013]

[0007] In some embodiments, the first conduit further comprises a first coating disposed thereon. In some embodiments, the first coating comprises a nickel, cobalt, carbon-based salt facing layer, or any combination thereof. In some embodiments, the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some embodiments, the second conduit further comprises a second coating disposed thereon. In some embodiments, the second coating comprises a nickel, cobalt, carbon-based salt facing layer, or any combination thereof. In some embodiments, the second coating is applied to the second conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

[0014]

[0008] In some embodiments, the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is different than the second coating. In some embodiments, the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is the same as the second coating.Attorney Docket No. 64117-709601

[0015]

[0009] In some embodiments, the first conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof. In some embodiments, the second conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof. In some embodiments, the alternating species reacts with the oxidizing species preferentially.

[0016]

[0010] In some embodiments, the first material is different from the second material. In some embodiments, the first material contains less nickel than the second material. In some embodiments, the first material contains at least about 10% less nickel than the second material. In some embodiments, the first material contains at least about 20% less nickel than the second material. In some embodiments, the first material contains at least about 50% less nickel than the second material. In some embodiments, the first material contains less cobalt than the second material. In some embodiments, the first material contains at least about 10% less cobalt than the second material. In some embodiments, the first material contains at least about 20% less cobalt than the second material. In some embodiments, the first material contains at least about 50% less cobalt than the second material. In some embodiments, the first material contains more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material. In some embodiments, the first material contains at least about 50% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material. In some embodiments, the first material contains at least about 100% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material. In some embodiments, the first material contains at least about 200% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

[0017] [OH] In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 1% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 5% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 10% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 20% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 40% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 50% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 1% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 5% metal oxides. In some embodiments, the first corrosion product and / or theAttorney Docket No. 64117-709601

[0018] second corrosion product comprises at most about 10% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 20% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 40% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 50% metal oxides.

[0019]

[0012] In some embodiments, the system further comprises a heat exchanger fluidically connected to the first conduit and the second conduit. In some embodiments, the heat exchanger is configured to cool the molten salt stream from the second temperature to the first temperature. In some embodiments, the heat exchanger is configured to receive a fluid that is below a melting temperature of the molten salt stream. In some embodiments, the heat exchanger is configured to transfer heat from the molten salt stream to the fluid. In some embodiments, the molten salt stream is configured to exit the second conduit, flow through the heat exchanger, and enter the first conduit.

[0020]

[0013] In some embodiments, an interior portion of the heat exchanger wall configured to contact the molten salt stream can be heated using impedance heating. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 1 °C below a freezing point of the molten salt stream. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 3 °C below a freezing point of the molten salt stream. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 5 °C below a freezing point of the molten salt stream. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 10 °C below a freezing point of the molten salt stream.

[0021]

[0014] In some embodiments, upon application of the impedance heating, a protective salt layer forms on the interior portion of the heat exchanger wall. In some embodiments, the protective salt layer is at most about 0.01 millimeters. In some embodiments, the protective salt layer is at most about 0.1 millimeters.

[0022]

[0015] In some embodiments, a current is applied to the interior portion of the heat exchanger wall. In some embodiments, the current is at least about 0.1 amperes. In some embodiments, the current is at least about 1 ampere. In some embodiments, the current is an alternating current (AC). In some embodiments, a voltage of the AC current is at least about 120 volts. In some embodiments, a voltage of the AC current is at least about 240 volts. In some embodiments, a voltage of the AC current is at least about 480 volts. In someAttorney Docket No. 64117-709601

[0023] embodiments, the current is a direct current (DC). In some embodiments, a voltage of the DC current is at least about 5 volts. In some embodiments, a voltage of the DC current is at least about 10 volts. In some embodiments, a voltage of the DC current is at least about 50 volts. In some embodiments, a voltage of the DC current is at least about 100 volts.

[0024]

[0016] In some embodiments, the system further comprises, an absorber fluidically connected to the first conduit or the second conduit, wherein the absorber is configured to contact the molten salt stream with a gaseous stream comprising CO2, to yield a molten salt stream comprising absorbed CO2. In some embodiments, the system further comprises, a desorber fluidically connected to the absorber, wherein the desorber is configured to release the absorbed CO2 from the molten salt stream.

[0025]

[0017] In some embodiments, the first conduit or the second conduit is configured to receive carbon monoxide (CO).

[0026]

[0018] In another aspect, disclosed herein is a method. In some embodiments, the method comprises (a) providing a first conduit comprised of a first material, wherein the first conduit is configured to receive a molten salt stream at a first temperature. In some embodiments, the molten salt stream comprises an oxidizing species. In some embodiments, the method comprises (b) providing a second conduit comprised of a second material fluidically connected to the first conduit, wherein the second conduit is configured to receive the molten salt stream at a second temperature. In some embodiments, the second temperature is higher than the first temperature. In some embodiments, a first corrosion product is formed in the first conduit. In some embodiments, the first corrosion product comprises the oxidizing species and the first material. In some embodiments, a second corrosion product is formed in the second conduit. In some embodiments, the second corrosion product comprises the oxidizing species and the second material. In some embodiments, a concentration of the second corrosion product is less than or equal to a concentration of the first corrosion product.

[0027]

[0019] In some embodiments, the oxidizing species comprises carbonates, oxides, metal oxides, peroxides, or any combination thereof. In some embodiments, the first temperature is from about 300 °C to about 700 °C. In some embodiments, the first temperature is from about 400 °C to about 700 °C. In some embodiments, the second temperature is from about 500 °C to about 900 °C. In some embodiments, the second temperature is from about 600 °C to about 900 °C. In some embodiments, the first material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof. In some embodiments, theAttorney Docket No. 64117-709601

[0028] second material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

[0029]

[0020] In some embodiments, the first conduit further comprises a first coating disposed thereon. In some embodiments, the first coating comprises a nickel, cobalt, carbon-based salt facing later, or any combination thereof. In some embodiments, the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some embodiments, the second conduit further comprises a second coating disposed thereon. In some embodiments, the second coating comprises a nickel, cobalt, carbon-based salt facing layer, or any combination thereof. In some embodiments, the second coating is applied to the second conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

[0030]

[0021] In some embodiments, the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is different than the second coating. In some embodiments, the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is the same as the second coating.

[0031]

[0022] In some embodiments, the first conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof. In some embodiments, the second conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof. In some embodiments, the alternating species reacts with the oxidizing species preferentially.

[0032]

[0023] In some embodiments, the first material is different from the second material. In some embodiments, the first material contains less nickel than the second material. In some embodiments, the first material contains at least about 10% less nickel than the second material. In some embodiments, the first material contains at least about 20% less nickel than the second material. In some embodiments, the first material contains at least about 50% less nickel than the second material. In some embodiments, the first material contains less cobalt than the second material. In some embodiments, the first material contains at least about 10% less cobalt than the second material. In some embodiments, the first material contains at least about 20% less cobalt than the second material. In some embodiments, the first material contains at least about 50% less cobalt than the second material. In some embodiments, the first material contains more iron, chromium, manganese, molybdenum, or any combinationAttorney Docket No. 64117-709601

[0033] thereof, than the second material. In some embodiments, the first material contains at least about 50% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material. In some embodiments, the first material contains at least about 100% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material. In some embodiments, the first material contains at least about 200% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

[0034]

[0024] In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 1% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 5% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 10% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 20% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 40% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at least about 50% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 1% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 5% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 10% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 20% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 40% metal oxides. In some embodiments, the first corrosion product and / or the second corrosion product comprises at most about 50% metal oxides.

[0035]

[0025] In some embodiments, the method further comprises providing a heat exchanger fluidically connected to the first conduit and the second conduit. In some embodiments, the heat exchanger is configured to cool the molten salt stream from the second temperature to the first temperature. In some embodiments, the heat exchanger is configured to receive a fluid that is below a melting temperature of the molten salt stream. In some embodiments, the heat exchanger is configured to transfer heat from the molten salt stream to the fluid. In some embodiments, the molten salt stream is configured to exit the second conduit, flow through the heat exchanger, and enter the first conduit.

[0036]

[0026] In some embodiments, an interior portion of the heat exchanger wall configured to contact the molten salt stream can be heated using impedance heating. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heatAttomey Docket No. 64117-709601

[0037] exchanger wall to within about 1 °C below a freezing point of the molten salt stream. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 3 °C below a freezing point of the molten salt stream. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 5 °C below a freezing point of the molten salt stream. In some embodiments, the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 10 °C below a freezing point of the molten salt stream.

[0038]

[0027] In some embodiments, upon application of the impedance heating, a protective salt layer forms on the interior portion of the heat exchanger wall. In some embodiments, the protective salt layer is at most about 0.01 millimeters. In some embodiments, the protective salt layer is at most about 0.1 millimeters.

[0039]

[0028] In some embodiments, the method further comprises applying a current to the first conduit and / or the second conduit. In some embodiments, the current is at least about 0.1 amperes. In some embodiments, the current is at least about 1 ampere. In some embodiments, the current is an alternating current (AC). In some embodiments, a voltage of the AC current is at least about 120 volts. In some embodiments, a voltage of the AC current is at least about 240 volts. In some embodiments, a voltage of the AC current is at least about 480 volts. In some embodiments, the current is a direct current (DC). In some embodiments, a voltage of the DC current is at least about 5 volts. In some embodiments, a voltage of the DC current is at least about 10 volts. In some embodiments, a voltage of the DC current is at least about 50 volts. In some embodiments, a voltage of the DC current is at least about 100 volts.

[0040]

[0029] In some embodiments, the method further comprises introducing carbon monoxide (CO) to the first conduit or the second conduit.

[0041]

[0030] In some embodiments, the method further comprises, (c) providing an absorber fluidically connected to the first conduit or the second conduit, wherein the absorber is configured to contact the molten salt stream with a gaseous stream comprising CO2, thereby obtaining a molten salt stream comprising absorbed CO2. In some embodiments, the method further comprises (d) providing a desorber fluidically connected to the absorber, wherein the desorber is configured to release the absorbed CO2 from the molten salt stream.

[0042]

[0031] In some embodiments, the method further comprises, prior to (a), introducing an additional corrosion product to the molten salt stream. In some embodiments, the additional corrosion product comprises the oxidizing species, carbon monoxide (CO), carbonites, the first material or the second material, or any combination thereof. In some embodiments, anAttorney Docket No. 64117-709601

[0043] amount of the additional corrosion product introduced to the molten salt stream is an equilibrium level of the first corrosion product or the second corrosion product. In some embodiments, an amount of the additional corrosion product introduced to the molten salt stream is at least about 10% of the equilibrium level of the first corrosion product or the second corrosion product. In some embodiments, an amount of the additional corrosion product introduced to the molten salt stream is at least about 90% of the equilibrium level of the first corrosion product or the second corrosion product.

[0044]

[0032] In some embodiments, the method further comprises introducing a current to provide electrons to the first conduit and / or the second conduit. In some embodiments, the electrons interact with the oxidizing species without oxidation of the first material or the second material. In some embodiments, the electrons are provided by one or more electrical connections located on either end of the first conduit or the second conduit. In some embodiments, the electrons are provided by one or more electrical connections located underneath the first conduit or the second conduit.

[0045]

[0033] In another aspect, disclosed herein is a method, comprising: (a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species; (b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature; and (c) introducing carbon monoxide (CO) to the first conduit or the second conduit, wherein introducing the CO to the first conduit or the second conduit reduces an amount of corrosion product formed in the first conduit or the second conduit, wherein the corrosion product comprises the oxidizing species and the material.

[0046]

[0034] In some embodiments, the oxidizing species comprises carbonates, metal oxides, peroxides, or any combination thereof. In some embodiments, the first temperature is from about 300 °C to about 700 °C. In some embodiments, the first temperature is from about 400 °C to about 700 °C. In some embodiments, the second temperature is from about 500 °C to about 900 °C. In some embodiments, the second temperature is from about 600 °C to about 900 °C. In some embodiments, the material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

[0047]

[0035] In some embodiments, the first conduit or the second conduit further comprises a first coating disposed thereon. In some embodiments, the first coating comprises a nickel, cobalt, carbon-based salt facing later, or any combination thereof. In some embodiments, the firstAttorney Docket No. 64117-709601

[0048] coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

[0049]

[0036] In some embodiments, the CO is bubbled through the molten salt stream in the first conduit or the second conduit. In some embodiments, the CO is introduced into a headspace above the molten salt stream in the first conduit or the second conduit.

[0050]

[0037] In another aspect, disclosed herein is a method, comprising: (a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species, wherein a corrosion product is formed in the first conduit, and wherein the corrosion product comprises the oxidizing species and the material; and (b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is greater than the first temperature, wherein the corrosion product is formed in the second conduit, wherein prior to (a) and (b), an additional corrosion product is introduced to the molten salt stream, and wherein the additional corrosion product comprises the oxidizing species and the material, wherein introducing the additional corrosion product to the first conduit or the second conduit reduces an amount of the corrosion product formed in the first conduit or the second conduit.

[0051]

[0038] In some embodiments, the oxidizing species comprises carbonates, metal oxides, peroxides, or any combination thereof. In some embodiments, the first temperature is from about 300 °C and about 700 °C. In some embodiments, the first temperature is from about 400 °C to about 700 °C. In some embodiments, the second temperature is from about 500 °C to about 900 °C. In some embodiments, the second temperature is from about 600 °C to about 900 °C. In some embodiments, the material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

[0052]

[0039] In some embodiments, an amount of the additional corrosion product introduced to the molten salt stream is an equilibrium level of the corrosion product. In some embodiments, an amount of the additional corrosion product introduced to the molten salt stream is at least about 10% of the equilibrium level of the corrosion product. In some embodiments, an amount of the additional corrosion product introduced to the molten salt stream is at least about 90% of the equilibrium level of the corrosion product.

[0053]

[0040] In another aspect, disclosed herein is a method, comprising: (a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a moltenAttorney Docket No. 64117-709601

[0054] salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species; (b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature; and (c) applying a current to the first conduit or the second conduit, wherein electrons provided by the current interact with the oxidizing species, thereby reducing an amount of corrosion product formed in the first conduit or the second conduit, wherein the corrosion product comprises the oxidizing species and the material.

[0055]

[0041] In some embodiments, the electrons reduce the oxidizing species without oxidation of the material. In some embodiments, the first temperature is from about 300 °C to about 700 °C. In some embodiments, the first temperature is from about 400 °C to about 700 °C. In some embodiments, the second temperature is from about 500 °C to about 900 °C. In some embodiments, the second temperature is from about 600 °C to about 900 °C. In some embodiments, the current is at least about 0.1 amperes. In some embodiments, the current is at least about 1 ampere. In some embodiments, the current is an alternating current (AC). In some embodiments, a voltage of the AC current is at least about 120 volts. In some embodiments, a voltage of the AC current is at least about 240 volts. In some embodiments, a voltage of the AC current is at least about 480 volts. In some embodiments, the current is a direct current (DC). In some embodiments, a voltage of the DC current is at least about 5 volts. In some embodiments, a voltage of the DC current is at least about 10 volts. In some embodiments, a voltage of the DC current is at least about 50 volts. In some embodiments, a voltage of the DC current is at least about 100 volts.

[0056]

[0042] In another aspect, disclosed herein is a method, comprising: (a) directing a molten salt stream through a first conduit of a heat exchanger; (b) directing a fluid through a second conduit of the heat exchanger, wherein the fluid is at a temperature below a melting point of the molten salt stream; and (c) using impedance heating, raising a temperature of an interior portion of a wall of the heat exchanger that contacts the molten salt stream, thereby controlling a thickness of a frozen salt layer on the interior portion of the wall of the heat exchanger.

[0057]

[0043] In some embodiments, the fluid comprises a different molten salt, water, steam, CO2, or a flue gas, or any combination thereof. In some embodiments, the heat exchanger is configured to transfer heat from the molten salt stream to the fluid. In some embodiments, the temperature of the interior portion of the wall of the heat exchanger is raised to about 1 °C below a freezing point of the molten salt stream. In some embodiments, the temperature ofAttorney Docket No. 64117-709601

[0058] the interior portion of the wall of the heat exchanger is raised to about 3 °C below a freezing point of the molten salt stream. In some embodiments, the temperature of the interior portion of the wall of the heat exchanger is raised to about 5 °C below a freezing point of the molten salt stream. In some embodiments, the temperature of the interior portion of the wall of the heat exchanger is raised to about 10 °C below a freezing point of the molten salt stream. In some embodiments, the thickness of the frozen salt layer is controlled to be at most about 0.01 millimeters. In some embodiments, the thickness of the frozen salt layer is controlled to be at most about 0.1 millimeters.

[0059]

[0044] In another aspect, disclosed herein is a method, comprising: (a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species; (b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature; and (c) introducing a reducing species to the first conduit or the second conduit, wherein introducing the reducing species to the first conduit or the second conduit reduces an amount of corrosion product formed in the first conduit or the second conduit, wherein the corrosion product comprises the oxidizing species and the material.

[0060]

[0045] In some embodiments, the reducing species comprise a sodium metal, a lithium metal, a potassium metal, a beryllium metal, a calcium metal, a chromium, a molybdenum, a carbon, a boron, or any combination thereof. In some embodiments, (c) introducing the reducing species to the first conduit or the second conduit reduces an adverse effect of the molten salt stream. In some embodiments, the adverse effect of the molten salt stream is less than about 50% increase in a viscosity of the molten salt stream without introducing the reducing species to the first conduit or the second conduit. In some embodiments, the adverse effect of the molten salt stream is less than about 50% increase in a melting point of the molten salt stream without introducing the reducing species to the first conduit or the second conduit. In some embodiments, the oxidizing species comprises carbonates, metal oxides, peroxides, or any combination thereof. In some embodiments, the first temperature is from about 300 °C to about 700 °C. In some embodiments, the first temperature is from about 400 °C to about 700 °C. In some embodiments, the second temperature is from about 500 °C to about 900 °C. In some embodiments, the second temperature is from about 600 °C to about 900 °C. In some embodiments, the material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof. In some embodiments, the first conduit or theAttorney Docket No. 64117-709601

[0061] second conduit further comprises a first coating disposed thereon. In some embodiments, the first coating comprises a nickel, cobalt, carbon-based salt facing later, or any combination thereof. In some embodiments, the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

[0062]

[0046] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

[0063] INCORPORATION BY REFERENCE

[0064]

[0047] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and / or take precedence over any such contradictory material.

[0065] BRIEF DESCRIPTION OF THE DRAWINGS

[0066]

[0048] The novel features of the systems and methods described herein are set forth with particularity in the appended claims. A better understanding of the features and advantages of the systems and methods described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments and the accompanying drawings (also “Figure” and “FIG.” herein) of which:

[0067]

[0049] FIG. 1 schematically illustrates a molten salt system utilizing a single salt-facing material in a higher temperature and lower temperature region, resulting in a higher concentration of corrosion products formed in the higher temperature region.

[0068]

[0050] FIG. 2 schematically illustrates a molten salt system utilizing a first salt-facing material in a lower temperature region and a second salt-facing material in a higher temperature region, resulting in an equal concentration of corrosion products formed in the lower and higher temperature regions.Attorney Docket No. 64117-709601

[0069]

[0051] FIG. 3 schematically illustrates a molten salt system utilizing a first salt-facing material in a lower temperature region and a second salt-facing material in a higher temperature region, resulting in a higher concentration of corrosion products formed in the lower temperature region.

[0070]

[0052] FIG. 4 schematically illustrates a frozen salt layer formed on a wall of a heat exchanger.

[0071]

[0053] FIG. 5 schematically illustrates a method for applying a current to a wall of a heat exchanger, resulting in a frozen salt layer of a controlled thickness.

[0072]

[0054] FIG. 6 schematically illustrates a method for applying a current to a material, thereby providing electrons to a stream with a molten salt.

[0073]

[0055] FIG. 7 shows a computer system that is programmed or otherwise configured to implement a method for of mitigating and controlling corrosion in any industrial process utilizing molten salts.

[0074] DETAILED DESCRIPTION

[0075]

[0056] While various embodiments of the systems and methods described herein have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the systems and methods described herein. It should be understood that various alternatives to the embodiments described herein may be employed. Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.”

[0076]

[0057] Whenever the term “at least,” “greater than” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0077]

[0058] Whenever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than,” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.Attorney Docket No. 64117-709601

[0078]

[0059] The term "about" as used herein referring to a number or a numerical range means that the number or numerical range referred to is an approximation within experimental variability (or within statistical experimental error). The number or numerical range may vary between 1% and 15% of the stated number or numerical range.

[0079]

[0060] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0080]

[0061] As used herein, the term “high purity” generally refers to a composition with low levels of impurities. In some cases, high purity refers to a mixture with a concentration of a component of about 80% to about 99.99%. In some cases, high purity refers to a mixture with a concentration of a component of about 80% to about 85%, about 80% to about 90%, about 80% to about 95%, about 80% to about 97%, about 80% to about 99%, about 80% to about 99.9%, about 80% to about 99.99%, about 85% to about 90%, about 85% to about 95%, about 85% to about 97%, about 85% to about 99%, about 85% to about 99.9%, about 85% to about 99.99%, about 90% to about 95%, about 90% to about 97%, about 90% to about 99%, about 90% to about 99.9%, about 90% to about 99.99%, about 95% to about 97%, about 95% to about 99%, about 95% to about 99.9%, about 95% to about 99.99%, about 97% to about 99%, about 97% to about 99.9%, about 97% to about 99.99%, about 99% to about 99.9%, about 99% to about 99.99%, or about 99.9% to about 99.99%. In some cases, high purity refers to a mixture with a concentration of a component of about 80%, about 85%, about 90%, about 95%, about 97%, about 99%, about 99.9%, or about 99.99%. In some cases, high purity refers to a mixture with a concentration of a component of at least about 80%, about 85%, about 90%, about 95%, about 97%, about 99%, or about 99.9%.

[0081]

[0062] The term “in proximity to,” as used herein, generally refers to a distance of at most 20 meters between A and B. For example, if it is stated that the absorber is positioned in proximity to the boiler, it is understood to mean that a boundary of the absorber is at a distance of at most 20 meters from a boundary of the boiler. In some embodiments, the distance may be at most 20 meters (m), 15 m, 10 m, 9 m, 8 m, 7 m, 6 m, 5 m, 4 m, 3 m, 2 m, 1 m, or less.

[0082]

[0063] The term “industrial process,” as used herein, generally refers to a process that extracts, transports, or processes raw materials to manufacture end products using physical, mechanical and / or chemical processes. An industrial process can generate electricity, steam, water, heat, cement, steel, hydrogen, pulp, paper, carbon dioxide, or a combination thereof. InAttorney Docket No. 64117-709601

[0083] some examples, an industrial process may refer to any process which generates a product of value. In some embodiments, the industrial process may generate carbon dioxide as a byproduct (e.g., by-product of combustion). In some embodiments, the industrial process may generate heat (e.g., thermal energy). Examples of industrial processes include coal fired power plants, oil fired power plants, gas fired power plants, or any other fossil-fuel fired power plants. A fossil fuel may comprise coal, petroleum, natural gas, oil shales, bitumens, tar sands, and heavy oils.

[0084]

[0064] The term “high temperature system” as used herein generally refers to an entire system or a portion of a system where high temperatures (e.g., exceeding 300 °C) may be reached. An industrial process may comprise one or more high temperature systems. The capture and release of carbon dioxide using molten salts, as described herein, may occur within or in proximity to a high temperature system (e.g., a portion of a system reaching temperatures of at least 300 °C). A high temperature system may comprise a boiler.

[0085]

[0065] The term “carbon capture system” as used herein generally refers to a system comprising at least an absorber and a desorber to capture and release carbon dioxide. A carbon capture system may be a closed-loop system for streams comprising molten salt to move within (e.g., from the absorber to the desorber and back to the absorber). A carbon capture system may be separate from the high temperature system or the system where an industrial process is occurring. A carbon capture system may be integrated directly into a high temperature system (e.g., boiler). A carbon capture system may be positioned near to (e.g., adjacent to) a high temperature system. A carbon capture system may be retroactively fitted (retrofitted) into a pre-existing high temperature system.

[0086]

[0066] Described herein are systems and methods of mitigating and controlling corrosion in any industrial process utilizing molten salts. As molten salts are predominately used as a heat transfer medium, salts are often cycled between hot and cold regions of a system over the course of operation. The molten salts may have a high solubility of oxidized metals and therefore the salt facing materials in the industrial process system may yield corrosion product. As corrosion and solubility are functions of temperature, mass transfer mediated by the salt can occur from salt facing materials existing in the hot region to those that exist in the cold region. Corrosion products will likely form at a greater extent at the hot region and then cycle within the molten salt to the colder region, where they now exist in higher concentrations than is favorable. This can lead to plate out or precipitation. The corrosion product lean salt can then cycle back to the hot region where the system is now out of equilibrium in the opposing direction, causing the formation andAttorney Docket No. 64117-709601

[0087] dissolution of additional corrosion products. This effect may reduce the amount of corrosion experienced by the material used in the hot region of a system but can exacerbate that experienced by the material used in the colder region of the system, as well as lead to potential issues associated with clogging and fouling.

[0088]

[0067] In addition to existing molten salt energy applications, newly discovered molten salt materials have also demonstrated potential for capturing CO2 emissions from industrial processes. For example, CO2 absorption by molten salt materials may occur at a lower temperature, and CO2 desorption from the molten salt materials may operate at a higher temperature. Prior to the molten salt cycling back to the absorption stage, the salt can be cooled to temperatures near its freezing point, which may present an opportunity to recover heat from the fluid. As carbon capture processes represent an added cost and complexity to existing systems, finding solutions that can deliver on both operational simplicity and costeffectiveness is critical for achieving widespread deployment.

[0089]

[0068] For molten salt systems, the preference for one material to corrode over another can be exploited. The tendency for a given alloy constituent to oxidize and dissolve into the molten salt is a function of the local composition of both the salt and alloy in addition to the local temperature. If the equilibrium level of dissolved corrosion products is known as a function of temperature and salt facing surface, then removal of the continuous mass transport mechanism highlighted in the background could potentially be achieved. By selectively choosing different materials for different temperature regions, a level of dissolved corrosion products could eventually be created such that it remains in equilibrium throughout the system despite the change in temperature.

[0090]

[0069] The relevant chemical reaction of the oxidization of a metal salt-facing layer can be represented by the following:

[0091]

[0092] + Ox(L)M0x{S) M0X(L)

[0093]

[0070] M indicates a metal constituent. Oxrepresents an oxidizing species. The oxidizing species can be a carbonate, a metal oxide, a peroxide, a sulfate, a borate, water, or any combination thereof. In some cases, the oxidizing species can comprise from about 0.1 wt% (weight percentage) to about 70 wt% of carbonate(s). In some cases, the oxidizing species can comprise up to about 65 wt%, up to about 66 wt%, up to about 67 wt%, up to about 68 wt%, up to about 69 wt%, or up to about 70 wt% of carbonate(s). In some cases, the carbonate can comprise a cation of an alkali metal as disclosed herein, an alkaline earth metalAttorney Docket No. 64117-709601

[0094] as disclosed herein, or a transition metal as disclosed herein, or a combination thereof. In some cases, the oxidizing species can comprise from about 0 wt% to about 15 wt% of metal oxide(s). In some cases, the metal oxide can comprise an alkali metal as disclosed herein, an alkaline earth metal as disclosed herein, or a transition metal as disclosed herein, or a combination thereof. In some cases, the oxidizing species can comprise from about 0 wt% to about 1 wt% of sulfate(s). In some cases, the sulfate can comprise a cation of an alkali metal as disclosed herein, an alkaline earth metal as disclosed herein, or a transition metal as disclosed herein, or a combination thereof. In some cases, the oxidizing species can comprise from about 0 wt% to about 1 wt% of peroxide(s). In some cases, the peroxide can comprise a cation of an alkali metal as disclosed herein, an alkaline earth metal as disclosed herein, or a transition metal as disclosed herein, or a combination thereof. MOXrepresents a corrosion product. The solid phase is represented by (S), and the liquid phase is represented by (L). A solid salt-facing material M(s) (a metal pipe, for example) can come into contact with an oxidizing species Ox(L) present in the molten salt, thereby forming a corrosion product MOx. The corrosion product MOx can initially be in the solid phase and dissolve to the liquid phase with increasing time and / or temperature, or can form directly in the liquid phase. For example, a salt-facing metal (e.g., Ni, Cr) may be oxidized to NiO or CT2O3 by the oxidizing species (e.g., Na2SO4). Na2SO4 as an oxidizing species may be reduced to Na2S. In some cases, NiO may function as an oxidizing species to react with Cr to yield corrosion product Cr2O3.

[0095]

[0071] For example, in a molten salt system with one salt-facing material, the temperature at a given region will be an adjustable factor for determining the tendency of the salt-facing material to oxidize and dissolve in the molten salt. For example, FIG. 1 shows a molten salt system utilizing a single salt-facing material (Material 2 or Mat 2). As shown in FIG. 1, the representative molten salt system has a higher temperature region (Temperature 2 or Temp 2) and a lower temperature region (Temperature 1 or Temp 1). As shown in FIG. 1, a molten salt can flow through a first conduit 101 at Temperature 1. Heat can then be added to the molten salt stream. Then, the heated molten salt stream can flow through a second conduit 102 at Temperature 2 (which is higher than Temperature 1 due to the added heat). Then, heat can be removed from the molten salt stream before it reenters the first conduit at Temperature 1. With all other factors being equal, the system of FIG. 1 will result in a greater amount of corrosion product being formed at Temperature 2 than at Temperature 1. Accordingly in FIG. 1, the corrosion products formed in the higher temperature region will cycle within theAttorney Docket No. 64117-709601

[0096] molten salt to the colder region, where they now exist in higher concentrations than is favorable. This can lead to unfavorable results like plate out or precipitation.

[0097]

[0072] Using dissimilar materials in the hotter (Temperature 2) and colder (Temperature 1) regions of a system can negate or flip the direction of corrosion product mass transport. In some cases, a more corrosion resistant salt-facing material can be used for a high temperature region of a process, and a less corrosion resistant salt-facing material can be used for a low temperature region for a process. A salt-facing material can be any material that contacts a molten borate salt in an industrial process. For example, a first salt-facing material (Material 1) can be used for a lower temperature (Temperature 1) region of a system, and a second salt-facing material (Material 2) can be used for a comparatively higher temperature region of a system (Temperature 2). Material 2 may be more corrosion resistant than Material 1.

[0098]

[0073] The systems and methods provided herein may control or mitigate corrosion product in the salt facing materials. The method may comprise selecting different salt facing materials of construction for hot (e.g., Temperature 2) and cold (e.g., Temperature 1) regions of the system such that the corrosion of Material 1 at Temperature 1 is similar or higher than Material 2 at Temperature 2. The method may comprise pre-loading molten salts with equilibrium levels of dissolved corrosion products for Material 2 at Temperature 2. The method may comprise using impedance heating during heat recovery of molten salts to raise the wall temperature just below the salt freezing point such that a thin layer of protective solid salt if formed, minimizing heat transfer resistance and pressure drop while providing a barrier for corrosion. The method may comprise using impedance heating as a source of electrons for oxidative species to protect the salt-facing materials (e.g., in the heat exchanger, the first conduit, or the second conduit, or other surfaces that contact the molten salt in the system). The systems provided herein may be used to implement the methods disclosed herein.

[0099]

[0074] In some cases, a system for corrosion control may comprise a first conduit and a second conduit. In some cases, the first conduit may comprise a first material (or Material 1). The first conduit may be configured to receive a molten salt stream at a first temperature (e.g., Temperature 1). In some cases, the second conduit may comprise a second material (or Material 2). The second conduit may be configured to receive the molten salt stream at a second temperature (e.g., Temperature 2).

[0100]

[0075] Material 1 can be selected so that the equilibrium level of corrosion products is substantially equal for Material 1 at Temperature 1 and for Material 2 at Temperature 2.Attorney Docket No. 64117-709601

[0101] In other words, by selectively choosing different materials for different temperature regions, a level of dissolved corrosion products can eventually be created such that it remains in equilibrium throughout the system despite the change in temperature throughout the system. This is shown in FIG.2. In FIG.2, the representative molten salt system has a higher temperature region (Temperature 2 or Temp 2) and a lower temperature region (Temperature 1 or Temp 1). As shown in FIG.2, a molten salt can flow through a first conduit 201 at Temperature 1. The first conduit can be made of a first material (or Material 1 or Mat 1, as used interchangeably herein). Heat can then be added to the molten salt stream. Then, the heated molten salt stream can flow through a second conduit 202 at Temperature 2 (which is higher than Temperature 1 due to the added heat). The second conduit can be made of a second material (or Material 2 or Mat 2, as used interchangeably herein). Then, heat can be removed from the molten salt stream before it reenters the first conduit at Temperature 1. Material 2 may be more corrosion resistant than Material 1. Material 1 can be selected so that, despite the change in temperature throughout the system, the concentration of corrosion products formed in the higher temperature region (the second conduit) is about the same as the concentration of corrosion products formed in the lower temperature region (the first conduit).

[0102] Accordingly in FIG.2, mass transport of the corrosion products between the higher temperature region and the lower temperature region may be expected to be zero or negligible.

[0103]

[0076] Material 1 can be selected so that the equilibrium level of corrosion products is greater for Material 1 at Temperature 1 than for Material 2 at Temperature 2. This is shown in FIG.3. In FIG.3, the representative molten salt system has a higher temperature region (Temperature 2 or Temp 2) and a lower temperature region (Temperature 1 or Temp 1). As shown in FIG. 3, a molten salt can flow through a first conduit 301 at Temperature 1. The first conduit 301 can be made of a first material (Material 1 or Mat 1). Heat can then be added to the molten salt stream. Then, the heated molten salt stream can flow through a second conduit 302 at Temperature 2 (which is higher than Temperature 1 due to the added heat). The second conduit can be made of a second material (Material 2 or Mat 2). Then, heat can be removed from the molten salt stream before it reenters the first conduit at Temperature 1. Material 2 may be more corrosion resistant than Material 1. Material 1 can be selected so that, despite the change in temperature throughout the system, the concentration of corrosion products formed in the higher temperature region (the second conduit) is less than the concentration ofAttorney Docket No. 64117-709601

[0104] corrosion products formed in the lower temperature region (the first conduit).

[0105] Accordingly in FIG. 3, the corrosion products formed in the lower temperature region will cycle within the molten salt to the higher temperature region. Therefore, a protective effect can be created for Material 2. Although Material 1 may corrode more quickly than if Material 2 had been chosen throughout, the protection applied to Material 2 at Temperature 2 and the likely cost difference between the two materials may result in net cost savings. For example, a less expensive material can be chosen for Material 1 than for Material 2. The protection applied to Material 2 can result in cost savings that outweigh the costs spent to replace Material 1, which is corroded more quickly.

[0106]

[0077] In some cases, a first corrosion product may form in the first conduit. The first corrosion product may be formed by a reaction between the first material and an oxidizing species. In some cases, the first corrosion product may comprise at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% metal oxides. In some cases, the first corrosion product may comprise at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 15%, at most about 10%, at most about 5%, at most about 4%, at most about 3%, at most about 2%, or at most about 1% metal oxides.

[0107]

[0078] In some cases, a second corrosion product may form in the second conduit. The second corrosion product may be formed by a reaction between the second material and an oxidizing species. In some cases, the first corrosion product may comprise at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% metal oxides. In some cases, the first corrosion product may comprise at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 15%, at most about 10%, at most about 5%, at most about 4%, at most about 3%, at most about 2%, or at most about 1% metal oxides.

[0108]

[0079] In some cases, the higher temperature region (Temperature 2) is at a temperature of about 500 °C to about 900 °C. In some cases, the higher temperature region (Temperature 2) is at a temperature of about 500 °C to about 550 °C, about 500 °C to about 600 °C, about 500 °C to about 650 °C, about 500 °C to about 700 °C, about 500 °C to about 750 °C, about 500 °C to about 800 °C, about 500 °C to about 850 °C, about 500 °C to about 900 °C, about 550 °C to about 600 °C, about 550 °C to about 650 °C, about 550 °C to about 700 °C, about 550 °C to about 750 °C, about 550 °C to about 800 °C, about 550 °C to about 850 °C, about 550Attorney Docket No. 64117-709601

[0109] °C to about 900 °C, about 600 °C to about 650 °C, about 600 °C to about 700 °C, about 600 °C to about 750 °C, about 600 °C to about 800 °C, about 600 °C to about 850 °C, about 600 °C to about 900 °C, about 650 °C to about 700 °C, about 650 °C to about 750 °C, about 650 °C to about 800 °C, about 650 °C to about 850 °C, about 650 °C to about 900 °C, about 700 °C to about 750 °C, about 700 °C to about 800 °C, about 700 °C to about 850 °C, about 700 °C to about 900 °C, about 750 °C to about 800 °C, about 750 °C to about 850 °C, about 750 °C to about 900 °C, about 800 °C to about 850 °C, about 800 °C to about 900 °C, or about 850 °C to about 900 °C. In some cases, the higher temperature region (Temperature 2) is at a temperature of about 500 °C, about 550 °C, about 600 °C, about 650 °C, about 700 °C, about 750 °C, about 800 °C, about 850 °C, or about 900 °C. In some cases, the higher temperature region (Temperature 2) is at a temperature of at least about 500 °C, at least about 550 °C, at least about 600 °C, at least about 650 °C, at least about 700 °C, at least about 750 °C, at least about 800 °C, or at least about 850 °C. In some cases, the higher temperature region (Temperature 2) is at a temperature of at most about 550 °C, at most about 600 °C, at most about 650 °C, at most about 700 °C, at most about 750 °C, at most about 800 °C, at most about 850 °C, or at most about 900 °C.

[0110]

[0080] In some cases, the lower temperature region (Temperature 1) is at a temperature of about 300 °C to about 700 °C. In some cases, the lower temperature region (Temperature 1) is at a temperature of about 300 °C to about 350 °C, about 300 °C to about 400 °C, about 300 °C to about 450 °C, about 300 °C to about 500 °C, about 300 °C to about 550 °C, about 300 °C to about 600 °C, about 300 °C to about 650 °C, about 300 °C to about 700 °C, about 350 °C to about 400 °C, about 350 °C to about 450 °C, about 350 °C to about 500 °C, about 350 °C to about 550 °C, about 350 °C to about 600 °C, about 350 °C to about 650 °C, about 350 °C to about 700 °C, about 400 °C to about 450 °C, about 400 °C to about 500 °C, about 400 °C to about 550 °C, about 400 °C to about 600 °C, about 400 °C to about 650 °C, about 400 °C to about 700 °C, about 450 °C to about 500 °C, about 450 °C to about 550 °C, about 450 °C to about 600 °C, about 450 °C to about 650 °C, about 450 °C to about 700 °C, about 500 °C to about 550 °C, about 500 °C to about 600 °C, about 500 °C to about 650 °C, about 500 °C to about 700 °C, about 550 °C to about 600 °C, about 550 °C to about 650 °C, about 550 °C to about 700 °C, about 600 °C to about 650 °C, about 600 °C to about 700 °C, or about 650 °C to about 700 °C. In some cases, the lower temperature region (Temperature 1) is at a temperature of about 300 °C, about 350 °C, about 400 °C, about 450 °C, about 500 °C, about 550 °C, about 600 °C, about 650 °C, or about 700 °C. In some cases, the lower temperature region (Temperature 1) is at a temperature of at least about 300 °C, at least about 350 °C, atAttorney Docket No. 64117-709601

[0111] least about 400 °C, at least about 450 °C, at least about 500 °C, at least about 550 °C, at least about 600 °C, or at least about 650 °C. In some cases, the lower temperature region (Temperature 1) is at a temperature of at most about 350 °C, at most about 400 °C, at most about 450 °C, at most about 500 °C, at most about 550 °C, at most about 600 °C, at most about 650 °C, or at most about 700 °C.

[0112]

[0081] In some cases, the higher temperature region (Temperature 2) may have a temperature that is at least about 10 °C, at least about 20 °C, at least about 30 °C, at least about 40 °C, at least about 50 °C, at least about 60 °C, at least about 70 °C, at least about 80 °C, at least about 90 °C, at least about 100 °C, at least about 150 °C, at least about 200 °C, or at least about 300 °C, higher than the temperature at the lower temperature region (Temperature 1).

[0113]

[0082] In some cases, salt-facing materials used in the lower temperature region (Material 1) can comprise carbon-based materials (e.g., graphite, carbon nanotubes, graphene, carbon black, carbon nanofibers), steels (e.g., stainless steels such as 304SS or 316SS, carbon steels, tool steel, or alloy steel), high nickel alloys (e.g., Inconel 625, Inconel 718, Inconel 600, Hastelloy X, Hastelloy C-276, Incoloy 800), high-cobalt alloys (e.g., Haynes 25, Haynes 188), or any combination or variants thereof.

[0114]

[0083] In some cases, salt-facing materials used in the higher temperature region (Material 2) can comprise carbon-based materials (e.g., graphite, carbon nanotubes, graphene, carbon black, carbon nanofibers), steels (e.g., stainless steels such as 304SS or 316SS, carbon steels, tool steel, or alloy steel), high nickel alloys (e.g., Inconel 625, Inconel 718, Inconel 600, Hastelloy X, Hastelloy C-276, Incoloy 800), high-cobalt alloys (e.g., Haynes 25, Haynes 188), or any combination or variants thereof.

[0115]

[0084] In some cases, the salt-facing material used in the higher temperature region (Material 2) is different than the salt-facing material used in the lower temperature region (Material 1). In some cases, Material 1 contains less nickel than Material 2. For example, Material 1 can include at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% less nickel than Material 2.

[0116]

[0085] In some cases, Material 1 contains less cobalt than Material 2. For example, Material 1 can include at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% less cobalt than Material 2.

[0117]

[0086] In some cases, Material 1 has a higher concentration of iron, chromium, manganese, molybdenum, or any combination thereof, than Material 2. In some cases, Material 1 contains more iron than Material 2. For example, Material 1 can include at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 100%, atAttorney Docket No. 64117-709601

[0118] least about 150%, or at least about 200% more iron than Material 2. In some cases, Material 1 contains more chromium than Material 2. For example, Material 1 can include at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 100%, at least about 150%, or at least about 200% more chromium than Material 2. In some cases, Material 1 contains more manganese than Material 2. For example, Material 1 can include at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 100%, at least about 150%, or at least about 200% more manganese than Material 2. In some cases, Material 1 contains more molybdenum than Material 2. For example, Material 1 can include at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 100%, at least about 150%, or at least about 200% more molybdenum than Material 2.

[0119]

[0087] In some cases, salt-facing materials used in the higher temperature region (Material 2) and / or the lower temperature region (Material 1) include a coating disposed thereon. In some cases, the coating comprises nickel, cobalt, or a carbon-based material, or a combination thereof. The coating can be applied via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some cases, a coating disposed on Material 2 (e.g., a second coating) is different from a coating disposed on Material 1 (e.g., a first coating). In some cases, a coating disposed on Material 2 is the same as a coating disposed on Material 1.

[0120]

[0088] The choice of different materials for the matching of corrosion product levels at different temperatures may be most relevant for near equilibrium conditions and beyond. In the establishment of equilibrium levels of dissolved corrosion products, significant degradation to the material has likely already occurred. To mitigate the effect of preequilibrium corrosion, the addition of corrosion products to the salt in advance of operation may prove beneficial. By pre-adding in corrosion products, near-equilibrium levels can be established, thereby reducing the extent, if any, of additional material that may be oxidized. Additional corrosion product (including metal oxides, represented by MOx) can be pre-loaded to the molten salt stream in advance of operation. In some cases, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 75%, at least about 90%, or at least about 95% of the equilibrium level of corrosion product is added to the molten salt stream in advance of operation. In some cases, instead of choosing different materials for higher and lower temperature regions of a molten salt system, a single material is used throughout, and corrosion is mitigated by pre-loading the molten salt with a level of corrosion product.Attorney Docket No. 64117-709601

[0121]

[0089] In lieu of, or in addition to pre-loaded corrosion products, additional components can be added to the molten salt stream in advance of operation. In some cases, carbon monoxide (CO) is added to the molten salt stream in advance of, or during, operation. Carbon monoxide can be added to the system at a higher temperature region or a lower temperature region. In some cases, carbon monoxide is bubbled through the molten salt stream or added to the headspace above the molten salt stream. Carbon monoxide can be added to the first conduit or the second conduit. In some cases, carbonites (CO22) are added to the molten salt stream in advance of, or during, operation.

[0122]

[0090] As described above, after exiting the second conduit, heat can be removed from the molten salt stream before it reenters the first conduit at Temperature 1. The molten salt stream may exit the second conduit at Temperature 2, flow through a heat exchanger where it is cooled down, and reenter the first conduit at Temperature 1. The heat exchanger may be fluidically connected to the first conduit and the second conduit. The molten salt may exit the second conduit, flow through the heat exchanger, and enter (or re-enter) the first conduit. The heat exchanger can have a fluid on the other side that is below a melting point of the molten salt stream. The fluid can include a different type of salt, water, steam, CO2, a flue gas, or any other fluid below the melting point of the molten salt stream. The heat exchanger may be configured to transfer heat from the molten salt stream to the fluid. In some cases, the salt facing side of the heat exchanger may comprise the first material. In some cases, the salt facing side of the heat exchanger may comprise the second material. In some cases, the salt facing side of the heat exchanger may comprise a material that is different than the first material and the second material. In some cases, the salt facing side of the heat exchanger may comprise carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof. In some cases, the heat transferred from the molten salt stream to the fluid is used to generate steam. Recovering heat from low melting point molten salts to generate steam can be challenging due to the large difference in heat transfer coefficient between the salt and steam side of the heat exchanger. Large buildups of frozen salt in the heat exchanger can lead to decreased heat transfer and a large pressure drop, increasing the size and cost of both the heat exchanger and corresponding pump. For example, FIG. 4 shows formation of a frozen salt layer on a material used within a heat exchanger. The frozen salt layer can inhibit heat transfer from the molten salt stream to the other fluid utilized in the heat exchanger (steam, for example).Attorney Docket No. 64117-709601

[0123]

[0091] In some cases, a frozen salt layer can also be beneficial by protecting the underlying material from corrosion. As shown in FIG. 5, impedance heating of the interior heat exchanger walls can be used to control a thickness of the frozen salt layer. The thickness of the frozen salt layer can be controlled such that the frozen salt layer: 1) is thick enough to protect the underlying material from corrosion, and 2) is not too thick such that it decreases heat transfer too much or causes a large pressure drop throughout the heat exchanger. A current (represented by dashed lines) can be applied to a heat transfer surface, thereby reducing the resistance of the material of the heat transfer surface. This can lead to heating within the walls, therefore raising the temperature of the heat transfer surface. The increased temperature of the heat transfer surface can eliminate or minimize formation of a frozen salt layer. By monitoring pressure drop and temperatures of the incoming and outcoming streams, applied current can be adjusted so that a thin layer of frozen salt forms, striking a balance between corrosion, heat transfer resistance, and pressure drop. In some cases, impedance heating is used to control the frozen salt layer such that it stays within a range of about 0.01 mm to about 0.1 mm. In some cases, impedance heating is used to control the frozen salt layer such that it never exceeds a thickness of more than 0.1 mm. In some cases, impedance heating is used to control the frozen salt layer such that it never exceeds a thickness of more than 0.05 mm. In some cases, impedance heating is used to control the frozen salt layer such that it never exceeds a thickness of more than 0.01 mm.

[0124]

[0092] In some cases, impedance heating is used to raise a temperature of the heat transfer surface (or the interior portion of the heat exchanger wall) to a temperature that is at most about 1 °C less than a freezing point of the molten salt stream. In some cases, impedance heating is used to raise a temperature of the heat transfer surface to a temperature that is at most about 3 °C less than a freezing point of the molten salt stream. In some cases, impedance heating is used to raise a temperature of the heat transfer surface to a temperature that is at most about 5 °C less than a freezing point of the molten salt stream. In some cases, impedance heating is used to raise a temperature of the heat transfer surface to a temperature that is at most about 10 °C less than a freezing point of the molten salt stream.

[0125]

[0093] Impedance heating in the form of an applied current can also provide corrosion protection by itself. For example, a continuous source of electrons to any salt-facing material (e.g., in the first conduit, the second conduit, or the heat exchanger, or any other surfaces contacting the molten salts) can result in reduction of oxidizing species (Ox) withoutAttorney Docket No. 64117-709601

[0126] oxidation of the base metal (M), thereby providing a mechanism of cathodic protection. The oxidizing species (Ox) may be reduced to a reduced species (Rd). For example, FIG. 6 shows a source of electrons (represented by a dashed line) being applied to a material of construction, thereby protecting the material from oxidation. Impedance heating can be used to apply a source of electrons to the heat exchanger surface. In some cases, impedance heating can be used to apply a source of electrons to the first conduit, the second conduit, or both. In some cases, the current may be applied to the heat exchanger surface, the first conduit, and / or the second conduit. In some cases, the current may be applied to the first material, the second material, or both. The electrons provided to the heat exchanger surface, the first conduit, and / or the second conduit may reduce the corrosion of the salt-facing material in the heat exchanger, the first conduit, and / or the second conduit. In some cases, the current may be from about 0.1 amperes (A) to about 5 A.

[0127]

[0094] In some cases, a current from about 0.1 A to about 5 A is applied to salt-facing material(s) (e.g., the heat exchanger surface material, the first material, or the second material). In some cases, a current of at least about 0.1 A is applied to the salt-facing material(s). In some cases, a current of at least about 1 A is applied to the salt-facing material(s).

[0128]

[0095] In some cases, an alternating current (AC) is applied to the salt-facing material(s). In some cases, at least about 10 volts (V), at least about 20 V, at least about 30 V, at least about 40 V, at least about 50 V, at least about 60 V, at least about 70 V, at least about 80 V, at least about 90 V, at least about 100 V, at least about 110 V, or at least about 120 V of AC current is applied to the salt-facing material(s). In some cases, at least about 240 V of AC current is applied to the salt-facing material(s). In some cases, at least about 480 V of AC current is applied to the salt-facing material(s).

[0129]

[0096] In some cases, a direct current (DC) is applied to the salt-facing material(s). In some cases, at least about 5 V, at least about 10 V, at least about 20 V, at least about 30 V, at least about 40 V, at least about 50 V, at least about 60 V, at least about 70 V, at least about 80 V, at least about 90 V, at least about 100 V of DC current is applied to the salt-facing material(s).

[0130]

[0097] Impedance heating can be applied to a salt-facing material of a conduit. The impedance heating can be supplied by electrical connections on either end of a conduit section (e.g., a pipe). Terminals can be attached to each end of the conduit, and the current can be passed through the conduit. In some cases, impedance heating can be supplied on theAttorney Docket No. 64117-709601

[0131] inlet and outlet piping of a larger component underneath the salt-facing material (e.g., underneath the insulation).

[0132]

[0098] In some cases, the first conduit may be configured to receive carbon black, graphite, carbon monoxide, metal oxides, and alternating species, or any combination thereof. In some cases, the alternating species may react with the oxidizing species preferentially such that the reaction between the first material and the oxidizing species is suppressed or reduced. In some cases, the alternating species may comprise a reducing species as disclosed herein. In some cases, the alternating species may comprise a hydrocarbon (e.g., alkane e.g., CH4, alkene, alkyne, or a polymer e.g., polyethylene), CO, H2, or solid alkali metal (e.g., Na, K), or a combination thereof.

[0133]

[0099] In some cases, the second conduit may be configured to receive carbon black, graphite, carbon monoxide, metal oxides, and alternating species, or any combination thereof. In some cases, the alternating species may react with the oxidizing species preferentially such that the reaction between the first material and the oxidizing species is suppressed or reduced. In some cases, the alternating species may comprise a reducing species as disclosed herein. In some cases, the alternating species may comprise a hydrocarbon (e.g., alkane e.g., CH4, alkene, alkyne, or a polymer e.g., polyethylene), CO, H2, or solid alkali metal (e.g., Na, K), or a combination thereof.

[0134]

[0100] In some cases, a reducing species can be added to the molten salt stream. The reducing species can preferentially react with the oxidizing species present in the molten salt stream rather than with the material of construction, without adversely affecting molten salt stream properties.

[0135]

[0101] In some cases, the reducing species can be a sodium metal, a lithium metal, a potassium metal, a beryllium metal, a calcium metal, a chromium, a molybdenum, a carbon, a boron, or any combination thereof.

[0136]

[0102] The reducing species can be added to the molten salt stream in advance of, or during, operation. The reducing species can be added to the first conduit or the second conduit. The reducing species can be added to a CO2 drum. The reducing species can be added once at the beginning of life, continuously during the lifetime of the system, intermittently during a maintenance interval, or any combination thereof. The reducing species can be added to the system at a higher temperature region or a lower temperature region.

[0137]

[0103] In some cases, the viscosity of the molten salt stream may increase due to the formation of the corrosion product. In some cases, the melting temperature of the molten salt stream may increase due to the formation of the corrosion product. In some cases, theAttorney Docket No. 64117-709601

[0138] reducing species may reduce the viscosity increase of the molten salt stream by at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% in comparison to when the reducing species is not introduced to the first conduit or the second conduit. In some cases, the reducing species may reduce the melting temperature increase of the molten salt stream by at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% in comparison to when the reducing species is not introduced to the first conduit or the second conduit.

[0139]

[0104] In some cases, the system may further comprise an absorber. The absorber may be fluidically connected to the first conduit and / or the second conduit. The absorber may be configured to contact the molten salt stream with a gaseous stream comprising CO2, thereby obtaining a molten salt stream comprising absorbed CO2.

[0140]

[0105] In some cases, the system may further comprise a desorber. The desorber may be fluidically connected to the absorber. The desorber may be configured to release the absorbed CO2 from the molten salt stream.

[0141]

[0106] In some cases, the present disclosure provides a method for corrosion control using the system as disclosed herein. The method may comprise providing a first conduit as disclosed herein to receive a molten salt stream at a first temperature (e.g., about 300 °C to 700 °C). The method may comprise providing a second conduit as disclosed herein to receive the molten salt stream at a second temperature (e.g., about 500 °C to 900 °C). The method may comprise fluidically connecting the second conduit to the first conduit. In some cases, the second temperature may be higher than the first temperature. In some cases, a first corrosion product may be formed in the first conduit. In some cases, a second corrosion product may be formed in the second conduit. In some cases, a concentration of the second corrosion product may be less than or equal to a concentration of the first corrosion product.

[0142]

[0107] In some cases, the first conduit may comprise a first material as disclosed herein. In some cases, the second conduit may comprise a second material as disclosed herein.

[0143]

[0108] In some cases, the method may comprise disposing a first coating as disclosed herein on or to the first conduit. In some cases, the method may comprise disposing the first coating on or to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some cases, the method may comprise disposing a second coating as disclosed herein on or to the second conduit. In some cases, the method may comprise disposing the second coating on or to the second conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. InAttorney Docket No. 64117-709601

[0144] some cases, the first coating may be different than the second coating. In some cases, the first coating may be the same as the second coating. In some cases, the first coating and the second coating may be disposed via a same method. In some cases, the first coating and the second coating may be disposed via a different method.

[0145]

[0109] In some cases, the method may comprise receiving carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof in the first conduit. In some cases, the method may comprise receiving carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof in the second conduit. In some cases, the alternating species may react with the oxidizing species preferentially such that the reaction between the first material and / or the second material and the oxidizing species is suppressed or reduced. In some cases, the alternating species may reduce the formation of the first corrosion product and / or the second corrosion product by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50%, as compared to when no such alternating species is used.

[0146] [HO] In some cases, the method may further comprise providing a heat exchanger. The method may comprise fluidically connect the heat exchanger to the first conduit and the second conduit. The heat exchanger may cool the molten salt stream from the second temperature to the first temperature. The heat exchanger may receive a fluid that is below a melting temperature of the molten salt stream. The heat exchanger may transfer heat from the molten salt stream to the fluid. The molten salt stream may exit the second conduit, flow through the heat exchanger, and enter the first conduit.

[0147] [Hl] In some cases, the method may further comprise heating an interior portion of the heat exchanger wall using impedance heating. The impedance heating may raise a temperature of the interior portion of the heat exchanger wall to within about 1 °C, within about 3 °C, within about 5 °C, or within about 10 °C below a freezing point of the molten salt stream. In some cases, upon application of the impedance heating, a protective salt layer may form on the interior portion of the heat exchanger wall. In some cases, the method may comprise forming the protective salt layer with a thickness of at most about 0.01 millimeters (mm), at most about 0.02 mm, at most about 0.03 mm, at most about 0.04 mm, at most about 0.05 mm, at most about 0.06 mm, at most about 0.07 mm, at most about 0.08 mm, at most about 0.09 mm, or at most about 0.1 mm.

[0148]

[0112] In some cases, the current may provide electrons (e.g., continues electrons) to the heat exchanger surface material, the first material, and / or the second material. In some cases, theAttorney Docket No. 64117-709601

[0149] electrons may interact with the oxidizing species without oxidation of the heat exchanger surface material, the first material, and / or the second material. In some cases, the current may reduce the oxidization of the first material and / or the second material that otherwise forms the first / second corrosion product. In some cases, the current may reduce the formation of the first corrosion product and / or the second corrosion product by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50%, as compared to when no current is applied. In some cases, the current may be from about 0.1 amperes (A) to about 5 A. In some cases, the method may further comprise providing the current (therefor the electrons) by one or more electrical connections located on either end of the heat exchanger, the first conduit, or the second conduit. In some cases, the method may further comprise providing the current (therefor the electrons) by one or more electrical connections located underneath the heat exchanger, the first conduit, or the second conduit.

[0150]

[0113] In some cases, the method may further comprise applying an alternating current (AC) to the first conduit and / or the second conduit. In some cases, the method may further comprise applying at least about 10 volts (V), at least about 20 V, at least about 30 V, at least about 40 V, at least about 50 V, at least about 60 V, at least about 70 V, at least about 80 V, at least about 90 V, at least about 100 V, at least about 110 V, at least about 120 V, at least about 240 V, or at least about 480 V of AC current to the first conduit and / or the second conduit.

[0151]

[0114] In some cases, the method may further comprise applying a direct current (DC) to the first conduit and / or the second conduit. In some cases, the method may further comprise applying at least about 5 V, at least about 10 V, at least about 20 V, at least about 30 V, at least about 40 V, at least about 50 V, at least about 60 V, at least about 70 V, at least about 80 V, at least about 90 V, at least about 100 V of DC current to the first conduit and / or the second conduit.

[0152]

[0115] In some cases, the method may further comprise introducing carbon monoxide (CO) to the first conduit and / or the second conduit. In some cases, the CO may reduce the oxidizing species or the first / second corrosion product. In some cases, the CO may reduce the formation of the first corrosion product and / or the second corrosion product by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50%, as compared to when no CO is introduced.Attorney Docket No. 64117-709601

[0153]

[0116] In some cases, the method may further comprise providing an absorber as disclosed herein. The method may comprise fluidically connecting the absorber to the first conduit or the second conduit. The absorber may contact the molten salt stream with a gaseous stream comprising CO2, thereby yielding a molten salt stream comprising absorbed CO2. In some cases, the method may further comprise providing a desorber as disclosed herein. The method may comprise fluidically connecting the desorber to the absorber. The desorber may release the absorbed CO2 from the molten salt stream.

[0154]

[0117] In some cases, the method may further comprise introducing an additional corrosion product to the molten salt stream. In some cases, the additional corrosion product may comprise the oxidizing species, carbon monoxide (CO), carbonites, the first material, or the second material, or any combination thereof. In some cases, the method may further comprise introducing an amount of the additional corrosion product to the molten salt stream at an equilibrium level of the first corrosion product or the second corrosion product. In some cases, an amount of the additional corrosion product introduced to the molten salt stream may be at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% of the equilibrium level of the first corrosion product or the second corrosion product.

[0155]

[0118] In some cases, the present disclosure provides a method for corrosion control using the system as disclosed herein. The method may comprise providing a first conduit as disclosed herein to receive a molten salt stream at a first temperature (e.g., about 300 °C to 700 °C). The first conduit may comprise a material. The method may comprise providing a second conduit as disclosed herein to receive the molten salt stream at a second temperature (e.g., about 500 °C to 900 °C). The second conduit may comprise the material. In some cases, the second conduit may comprise a different material than the material of the first conduit. The method may comprise fluidically connecting the second conduit to the first conduit. In some cases, the second temperature may be higher than the first temperature. In some cases, the method may comprise introducing carbon monoxide (CO) to the first conduit and / or the second conduit. In some cases, introducing the CO to the first conduit and / or the second conduit may reduce an amount of corrosion product formed in the first conduit and / or the second conduit. In some cases, the material may comprise carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof. In some cases, a first corrosion product may be formed in the first conduit. In some cases, a second corrosion product may be formed in the second conduit.Attorney Docket No. 64117-709601

[0156]

[0119] In some cases, the method may comprise disposing a coating (e.g., the first coating or the second coating, as disclosed herein) on or to the first conduit. In some cases, the method may comprise disposing the coating on or to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some cases, the method may comprise disposing a coating (e.g., the first coating or the second coating, as disclosed herein) on or to the second conduit. In some cases, the method may comprise disposing the coating on or to the second conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some cases, the coating on the first conduit may be different than the coating on the second conduit. In some cases, the coating on the first conduit may be the same as the coating on the second conduit.

[0157]

[0120] In some cases, the method may comprise bubbling the CO through the molten salt stream in the first conduit or the second conduit. In some cases, the method may comprise introducing the CO into a headspace above the molten salt stream in the first conduit or the second conduit.

[0158]

[0121] In some cases, the present disclosure provides a method for corrosion control using the system as disclosed herein. The method may comprise providing a first conduit as disclosed herein to receive a molten salt stream at a first temperature (e.g., about 300 °C to 700 °C). The first conduit may comprise a material. The method may comprise providing a second conduit as disclosed herein to receive the molten salt stream at a second temperature (e.g., about 500 °C to 900 °C). The second conduit may comprise the material. In some cases, the second conduit may comprise a different material than the material of the first conduit. The method may comprise fluidically connecting the second conduit to the first conduit. In some cases, the second temperature may be higher than the first temperature. In some cases, a first corrosion product may be formed in the first conduit. The first corrosion product may be formed by reacting the material of the first conduit with an oxidizing species in the molten salt stream. In some cases, a second corrosion product may be formed in the second conduit. The second corrosion product may be formed by reacting the material of the second conduit with an oxidizing species in the molten salt stream.

[0159]

[0122] In some cases, the method may further comprise introducing an additional corrosion product to the molten salt prior to introducing the molten salt stream to the first conduit and the second conduit. In some cases, the additional corrosion product may comprise an oxidizing species and the material of the first conduit or the second conduit. In some cases, introducing the additional corrosion product to the first conduit or the second conduit mayAttorney Docket No. 64117-709601

[0160] reduce an amount of the corrosion product formed in the first conduit or the second conduit. In some cases, an amount of the additional corrosion product introduced to the molten salt stream may be at an equilibrium level of the corrosion product (e.g., the first corrosion product or the second corrosion product). In some cases, an amount of the additional corrosion product introduced to the molten salt stream may be at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% of the equilibrium level of the corrosion product (e.g., the first corrosion product or the second corrosion product).

[0161]

[0123] In some cases, the present disclosure provides a method for corrosion control using the system as disclosed herein. The method may comprise providing a first conduit as disclosed herein to receive a molten salt stream at a first temperature (e.g., about 300 °C to 700 °C). The first conduit may comprise a material. The method may comprise providing a second conduit as disclosed herein to receive the molten salt stream at a second temperature (e.g., about 500 °C to 900 °C). The second conduit may comprise the material. In some cases, the second conduit may comprise a different material than the material of the first conduit. The method may comprise fluidically connecting the second conduit to the first conduit. In some cases, the second temperature may be higher than the first temperature. In some cases, the molten salt stream may comprise an oxidizing species.

[0162]

[0124] In some cases, a corrosion product may form at the first conduit or the second conduit, from a reaction between the material and an oxidizing species in the molten salt stream. In some cases, the method may comprise applying a current to the first conduit or the second conduit. In some cases, the current may provide electrons. In some cases, the electrons provided by the current may interact with the oxidizing species, thereby reducing an amount of corrosion product formed in the heat exchanger surface material, the first material, and / or the second material. In some cases, the electrons may reduce the oxidizing species without oxidation of the material.

[0163]

[0125] In some cases, the current may reduce the formation of the corrosion product (e.g., the first corrosion product and / or the second corrosion product) by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50%, as compared to when no current is applied. In some cases, the current may be from about 0.1 A to about 5 A. In some cases, the method may further comprise providing the current (therefore the electrons) by one or more electrical connections located on either end of the heat exchanger, the first conduit, or the second conduit. In some cases, the method may further compriseAttorney Docket No. 64117-709601

[0164] providing the current (therefor the electrons) by one or more electrical connections located underneath the heat exchanger, the first conduit, or the second conduit.

[0165]

[0126] In some cases, the method may further comprise applying an AC current to the first conduit and / or the second conduit. In some cases, the method may further comprise applying at least about 10 volts (V), at least about 20 V, at least about 30 V, at least about 40 V, at least about 50 V, at least about 60 V, at least about 70 V, at least about 80 V, at least about 90 V, at least about 100 V, at least about 110 V, at least about 120 V, at least about 240 V, or at least about 480 V of AC current to the first conduit and / or the second conduit.

[0166]

[0127] In some cases, the method may further comprise applying a DC current to the first conduit and / or the second conduit. In some cases, the method may further comprise applying at least about 5 V, at least about 10 V, at least about 20 V, at least about 30 V, at least about 40 V, at least about 50 V, at least about 60 V, at least about 70 V, at least about 80 V, at least about 90 V, at least about 100 V of DC current to the first conduit and / or the second conduit.

[0167]

[0128] In some cases, the present disclosure provides a method for corrosion control using the system as disclosed herein. The method may comprise directing a molten salt stream through a first conduit of a heat exchanger. The method may comprise directing a fluid through a second conduit of the heat exchanger. The fluid may be at a temperature below a melting point of the molten salt stream. The method may comprise using impedance heating to raise a temperature of an interior portion of a wall of the heat exchanger that contacts the molten salt stream. The method disclosed herein may control a thickness of a frozen salt layer on the interior portion of the wall of the heat exchanger. In some cases, the fluid may comprise a different molten salt, water, steam, CO2, or a flue gas, or any combination thereof. In some cases, the method may comprise using the heat exchanger to transfer heat from the molten salt stream to the fluid. In some cases, the temperature of the interior portion of the wall of the heat exchanger may be raised to at least about 1 °C, at least about 2 °C, at least about 3 °C, at least about 4 °C, at least about 5 °C, at least about 10 °C, at least about 15 °C, or at least about 20 °C below a freezing point of the molten salt stream. In some cases, the temperature of the interior portion of the wall of the heat exchanger may be raised to at most about 20 °C, at most about 15 °C, at most about 10 °C, at most about 5 °C, at most about 4 °C, at most about 3 °C, at most about 2 °C, or at most about 1 °C below a freezing point of the molten salt stream.

[0168]

[0129] In some cases, the method may control the thickness of the frozen salt layer to be at most about 0.01 mm, at most about 0.02 mm, at most about 0.03 mm, at most about 0.04 mm,Attorney Docket No. 64117-709601

[0169] at most about 0.05 mm, at most about 0.06 mm, at most about 0.07 mm, at most about 0.08 mm, at most about 0.09 mm, or at most about 0.1 mm.

[0170]

[0130] In some cases, the present disclosure provides a method for corrosion control using the system as disclosed herein. The method may comprise providing a first conduit as disclosed herein to receive a molten salt stream at a first temperature (e.g., about 300 °C to 700 °C). The first conduit may comprise a material. The method may comprise providing a second conduit as disclosed herein to receive the molten salt stream at a second temperature (e.g., about 500 °C to 900 °C). The second conduit may comprise the material. In some cases, the second conduit may comprise a different material than the material of the first conduit. The method may comprise fluidically connecting the second conduit to the first conduit. In some cases, the second temperature may be higher than the first temperature. In some cases, the molten salt stream may comprise an oxidizing species. In some cases, a corrosion product may form at the first conduit or the second conduit, from a reaction between the material and an oxidizing species in the molten salt stream. In some cases, the method may comprise introducing a reducing species to the first conduit or the second conduit. The reducing species may reduce an amount of corrosion product formed in the first conduit or the second conduit.

[0171]

[0131] In some cases, the reducing species may comprise a sodium metal, a lithium metal, a potassium metal, a beryllium metal, a calcium metal, a chromium, a molybdenum, a carbon, a boron, or any combination thereof. In some cases, the reducing species may reduce an adverse effect of the molten salt stream due to the formation of the corrosion product. In some cases, the reducing species may reduce the viscosity increase of the molten salt stream by at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% in comparison to when the reducing species is not introduced to the first conduit or the second conduit. In some cases, the reducing species may reduce the melting temperature increase of the molten salt stream by at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% in comparison to when the reducing species is not introduced to the first conduit or the second conduit.

[0172]

[0132] In some cases, the method may comprise disposing a coating (e.g., the first coating or the second coating, as disclosed herein) on or to the first conduit. In some cases, the method may comprise disposing the coating on or to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some cases, the method may comprise disposing a coating (e.g., the first coating or the second coating, as disclosed herein) on or to the second conduit. In some cases, the method may comprise disposing the coating on or to the second conduitAttorney Docket No. 64117-709601

[0173] via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof. In some cases, the coating on the first conduit may be different than the coating on the second conduit. In some cases, the coating on the first conduit may be the same as the coating on the second conduit.

[0174] Molten Salt Streams

[0175]

[0133] The corrosion mitigation methods and systems described herein can be used for any molten salt or combination of molten salts. The molten salt may comprise a molten borate salt. The borate salt may comprise a formula of AXBI-X0I.5-X. In such formulas, “A” refers to an alkali metal, “B” refers to boron, “O” refers to oxygen, and “x” is a value between 0 and 1.

[0176]

[0134] In some embodiments, “x” is a number between 0 and 1. In some embodiments, “x” is about 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, or 0.99. In some embodiments, “x” is a number between about 0.25 and about 0.98. In some embodiments, “x” is a number between about 0.3 and about 0.95. In some embodiments, “x” is a number between about 0.5 and about 0.95. In some embodiments, “x” is a number between about 0.6 and about 0.9. In some embodiments “x” is about 0.75.

[0177]

[0135] In some embodiments, “A” comprises alkali metal. An alkali metal may be lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), or francium (Fr). In some embodiments, “A” is lithium. In some embodiments, “A” is sodium. In some embodiments, “A” is potassium. In some embodiments, “A” is rubidium. In some embodiments, “A” is cesium. In some embodiments, “A” is francium. In some embodiments, “A” may comprise an alkaline earth metal. An alkali earth metal may be beryllium (Be), strontium (Sr), calcium (Ca), magnesium (Mg), barium (Ba), or radium (Ra). In some embodiments, “A” may be any cation comprising a positive charge of +1. In some embodiments, “A” may comprise a transition metal with a +1 charge (e.g., copper, silver, or any other transition metal). In some embodiments “A” may comprise a transition metal. A transition metal may be scandium (Sc), yttrium (Y), lanthanum (La), actinium (Ac), titanium (Ti), zirconium (Zr), hafnium (Hf), rutherfordium (Rf), vanadium (V), niobium (Nb), tantalum (Ta), dubnium (Db), chromium (Cr), molybdenum (Mo), tungsten (W), seaborgium (Sg), manganese (Mn), technetium (Tc), rhenium (Re), bohrium (Bh), iron (Fe), ruthenium (Ru), osmium (Os), hassium (Hs), cobalt (Co), rhodium (Rh), iridium (Ir), meitnerium (Mt), nickel (Ni), palladium (Pd), platinum (Pt), darmstadtium (Ds), copper (Cu), silver (Ag), gold (Au), roentgenium (Rg), zinc (Zn), cadmium (Cd), mercury (Hg), or copemicium (Cn). In some embodiments, the borate salt may comprise a mixture of metals. A may comprise a mixture of alkali metals, alkaline earthAttorney Docket No. 64117-709601

[0178] metals, transition metals, or any combination thereof. For example, the formula for the borate salt may comprise (A1yA2i-y)xBi-xOi.5-x, where A1and A2are each a separate “A” as described herein, “y” is a number between 0 and 1, and “x” is a number between 0 and 1. In some embodiments, a borate salt may comprise a mixture of lithium and sodium. In some embodiments A1is lithium and A2is sodium. In some embodiments A1is lithium, A2is sodium, y is 0.4, and x is 0.75. In some embodiments A1is lithium, A2is sodium, y is 0.5, and x is 0.75. In some embodiments A1is lithium, A2is sodium, y is 0.33, and x is 0.75. In some embodiments, the borate salt may comprise a composition of Na0.75B0.25O0.75, (Lio.5Nao.5)o.75Bo.250o.75, (Lio.4Nao.6)o.75Bo.250o.75, (Lio.3Nao.7)o.75Bo.250o.75, (Lio.2Nao.s)o.75Bo.250o.75, (Lio.lNao.9)o.75Bo.250o.75, (Lio.33Nao.33Ko.33)o.75Bo.250o.75, (Lio.4Nao.5Ko.!) 0.75B0.25O0.75, (Lio.7Nao.3)o.5Bo.50i.o, (Lio.sNao.sjo.ssBo.nOo.e?, (Lio.7Nao.3)o.83Bo.i70o.67, or (Lio.3Nao.7)o.83Bo.i70o.67.

[0179]

[0136] In some embodiments, a borate salt may comprise an impurity or a contaminant. For example, the impurity may comprise Iron (Fe), Chromium (Cr), Nickel (Ni), Manganese (Mn), Molybdenum (Mo), Cobalt (Co), Vanadium (V), Copper (Cu), Zinc (Zn), Aluminum (Al), Titanium (Ti), Cadmium (Cd), Mercury (Hg), Potassium (K), Magnesium (Mg), Silicon (Si), Phosphorus (P), and Sulfur (S), or any other contaminants. A quantity of an impurity in the borate salt may be at most about 30 weight percent (wt%), 20 wt%, 10 wt%, 5 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.08 wt %, 0.05 wt%, 0.01 wt%, 0.005 wt %, 0.001 wt%, or less.

[0180]

[0137] In some embodiments, a borate salt comprising the formula A0.75B0.25O0.75 may be represented as A3BO3. In some embodiments, a borate salt comprising the formula A0.5B0.5O10 may be represented as ABO2. In some embodiments, a borate salt comprising the formula A0.83B0.17O0.67 may be represented as A5BO4.

[0181] Carbon Capture System

[0182]

[0138] The systems and methods for corrosion control and mitigation described above can be used in a carbon capture system that uses molten salts to absorb and desorb carbon dioxide.

[0183]

[0139] A carbon capture system may comprise an absorber. The absorber may be positioned within a high temperature system of an industrial process. The absorber may be positioned adjacent to a high temperature system of an industrial process. The absorber may be positioned within a boiler of the system. In some embodiments, the absorber may be positioned adjacent to the boiler of the system. In some embodiments, the absorber may be positioned in proximity to the boiler of the system. In some embodiments, the absorber mayAttorney Docket No. 64117-709601

[0184] be positioned within a convection section of the boiler. An absorber may comprise one or more types of molten salt, where the molten salt is used to sequester (e.g., absorb carbon dioxide). The absorber may operate at a temperature of at least 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C, 1200 °C, or any other temperature within the preceding range. In some embodiments, the temperature of the absorber may exceed about 400 °C. In some embodiments, the temperature of the absorber may exceed about 500 °C. In some embodiments, the temperature of the absorber may exceed about 600 °C. In some embodiments, the temperature of the absorber may exceed about 700 °C. In some embodiments, the temperature of the absorber may be about 300 °C to about 800 °C. In some embodiments, the temperature of the absorber may be about 400 °C to about 700 °C. In some embodiments, the temperature of the absorber may be about 400 °C to about 600 °C.

[0185]

[0140] Molten salt in an absorber may capture at least about 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 100% of carbon containing material (e.g., carbon dioxide) that it contacts. In some embodiments, an absorber may capture at least about 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, or 100% of carbon containing material (e.g., carbon dioxide) that it contacts. The absorber may capture at least about 50% of the carbon containing material it contacts, about 75% of the carbon containing material it contacts, about 80% of the carbon containing material it contacts, about 85% of the carbon containing material it contacts, about 90% of the carbon containing material it contacts, or about 95% of the carbon containing material it contacts.

[0186]

[0141] A carbon capture system may comprise a desorber. The desorber may be positioned within a high temperature system. In some embodiments, the desorber may be positioned adjacent to a high temperature system. In some embodiments, the desorber may be positioned in proximity to a high temperature system. The desorber may be positioned within a boiler of the system. In some embodiments, the desorber may be positioned adjacent to the boiler of the system. In some embodiments, the desorber may be positioned in proximity to the boiler of the system. In some embodiments, the desorber may be positioned within a radiant section of the boiler. A desorber may be used to release, or desorb, carbon dioxide from a molten salt. The desorber may have a temperature of at least 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C, 1200 °C, 1400 °C, 1600 °C, 2000 °C, or any other temperature within the preceding range. In some embodiments, the temperature of the desorber may exceed about 700 °C. In some embodiments, the temperature of the absorber may exceed about 800 °C. In some embodiments, the temperature of the absorber may exceed about 900 °C. In some embodiments, the temperature of the absorber may exceedAttorney Docket No. 64117-709601

[0187] about 1000 °C. In some embodiments, the temperature of the absorber may be about 600 °C to about 1200 °C. In some embodiments, the temperature of the absorber may be about 700 °C to about 1000 °C. In some embodiments, the temperature of the absorber may be about 700 °C to about 900 °C.

[0188]

[0142] The desorber may release about 10% of the carbon containing material absorbed within the stream comprising molten salt, about 20% of the carbon containing material absorbed within the stream comprising molten salt, about 30% of the carbon containing material absorbed within the stream comprising molten salt, about 40% of the carbon containing material absorbed within the stream comprising molten salt , about 50% of the carbon containing material absorbed within the stream comprising molten salt, about 60% of the carbon containing material absorbed within the stream comprising molten salt, about 70% of the carbon containing material absorbed within the stream comprising molten salt, about 80% of the carbon containing material absorbed within the stream comprising molten salt, about 85% of the carbon containing material absorbed within the stream comprising molten salt, about 90% of the carbon containing material absorbed within the stream comprising molten salt, about 95% of the carbon containing material absorbed within the stream comprising molten salt, or about 99% of the carbon containing material absorbed within the stream comprising molten salt, or about 100% of the carbon containing material absorbed within the stream comprising molten salt. In some embodiments, the desorber may release about 10% to about 100% of the carbon containing material absorbed within the stream comprising molten salt. In some embodiments, the desorber may release about 40% to about 100% of the carbon containing material absorbed within the stream comprising molten salt. For example, a carbon rich stream comprising molten salt may comprise about 50% carbon dioxide and comprise about 30% carbon dioxide in the carbon lean stream comprising molten salt upon desorption of carbon dioxide, thereby effectively releasing about 40% of the carbon dioxide absorbed in the stream comprising molten salt.

[0189]

[0143] In some embodiments, the desorber may have a temperature that is higher than the absorber. For example, if the absorber has a temperature of about 600 °C, then the desorber may have a temperature of at least 900 °C. In another example, if the absorber has a temperature of about 700 °C, then the desorber may have a temperature of at least 1000 °C. The temperature difference between an absorber and a desorber may be at least about 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, or more. In some embodiments, the temperature difference between an absorber and a desorber may be at least about 100 °C. In some embodiments, the temperature difference between an absorber and a desorber may be at leastAttorney Docket No. 64117-709601

[0190] about 200 °C. In some embodiments, the temperature difference between an absorber and a desorber may be at least about 300 °C. In some embodiments, a desorber may consume heat in the radiant section of the high temperature system which may prevent exceedingly high temperatures at the desorber (e.g., at least 1,000 °C). In such embodiments, an exceedingly high temperature at the desorber may be at least 1000 °C, at least 1200 °C, at least 2000 °C, or more. A desorber may reduce heat flux through wing-walls positioned in the radiant section of the high temperature system. In some embodiments, the higher temperature of the desorber (in comparison to the absorber) may facilitate desorption of carbon dioxide from a molten salt.

[0191]

[0144] An absorber may be used to contact a gaseous carbon containing material (e.g., carbon dioxide, carbon monoxide) with a molten salt, described elsewhere herein, thereby transferring the gaseous carbon containing material to a liquid stream of the molten salt A stream comprising absorbed carbon containing material may be referred to as a carbon rich stream or a rich stream herein. The rich stream can be directed to a desorber where the molten salt may be regenerated and a stream comprising desorbed carbon containing material may be further cooled, compressed, and / or prepared for export elsewhere in the system or outside of the system. For example, desorbed carbon containing material may be exported for injecting into geological formations, or converted to products like fuel or other chemicals. The regenerated molten salt may also be referred to as carbon lean molten salt or lean molten salt herein. The lean molten salt may be transferred back to the absorber for another cycle of carbon capture.

[0192]

[0145] Absorption of carbon containing material alter the structure of the initial borate salt. For example, carbon dioxide may react with a borate salt to form a carbonate and an altered borate salt as shown below:

[0193] A3BO3 + CO2 — > ABO2 + A2CO3,

[0194] (Lio.sNao.sjsBCh + CO2 — > (Lio.sNao.sjBCh + (Lio.sNao.s^CCh,

[0195] A0.75B0.25O0.75 + CO2 A0.5B0.5O1.0 + A2CO3, l / (x-0.5) AXBI-XOI.5-X + CO2 (l-x) / (x-0.5) ABO2 + A2CO3 where 0.5 < x < 1.0, or A

[0196]

[0197] xB1.xO1.5-x + CO2 AyB i-yO 1 5-y + AZCO3where 0.0 < x < 1.0; 0.0 < y < 1.0; 0.0 < z < 2.0. The reaction between a borate salt and carbon dioxide may be reversible. In some embodiments, the resulting carbonate (A2CO3) is a liquid. In some embodiments, other components of the flue gas (e.g., components which were not absorbed by the borate salt) may exit the system through an exhaust stack.Attorney Docket No. 64117-709601

[0198]

[0146] Desorbed carbon containing material may be prepared for export from the desorber. In some cases, desorbed carbon containing material may be stored on site. In some embodiments, the desorbed carbon containing material may be provided as an export stream. In some embodiments, the export stream may comprise a concentration of carbon containing material (e.g., carbon dioxide) at a concentration of at least about 50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.9%, or more. In some embodiments, the export stream may comprise a concentration of carbon containing material at a concentration of at least about 80%. In some embodiments, the export stream may comprise a concentration of carbon containing material at a concentration of at least about 90%. In some embodiments, the export stream may comprise a concentration of carbon containing material at a concentration of at least about 95%. In some embodiments, the export stream may comprise a concentration of carbon containing material at a concentration of at least about 99%. In some embodiments, the export stream may comprise a concentration of carbon containing material at a concentration of at least about 99.9%.

[0199]

[0147] In some embodiments, the export stream may pass through the convection section of the high temperature system. Passing the export stream through the convection section may cool the stream and recover heat through generation of steam, or transfer of heat to another process fluid.

[0200] Computer Systems

[0201]

[0148] In an aspect, the present disclosure provides computer systems that are programmed or otherwise configured to implement methods of the disclosure, e.g., any of the subject methods for controlling or mitigating corrosion. FIG. 7 shows a computer system 701 that is programmed or otherwise configured to implement a method controlling or mitigating corrosion products as described herein. The computer system 701 may be configured to, for example, control the flow of molten salts through one or more conduits, monitor and measure a level of one or more corrosion products, or measure a thickness of a frozen salt layer. The computer system 701 can be an electronic device of a user or a computer system that is remotely located with respect to the electronic device. The electronic device can be a mobile electronic device.

[0202]

[0149] The computer system 701 may include a central processing unit (CPU, also "processor" and "computer processor" herein) 705, which can be a single core or multi core processor, or a plurality of processors for parallel processing. The computer system 701 also includes memory or memory location 710 (e.g., random-access memory, read-only memory,Attorney Docket No. 64117-709601

[0203] flash memory), electronic storage unit 715 (e.g., hard disk), communication interface 720 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 725, such as cache, other memory, data storage and / or electronic display adapters. The memory 710, storage unit 715, interface 720 and peripheral devices 725 are in communication with the CPU 705 through a communication bus (solid lines), such as a motherboard. The storage unit 715 can be a data storage unit (or data repository) for storing data. The computer system 701 can be operatively coupled to a computer network ("network") 730 with the aid of the communication interface 720. The network 730 can be the Internet, an internet and / or extranet, or an intranet and / or extranet that is in communication with the Internet. The network 730 in some cases is a telecommunication and / or data network. The network 730 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 730, in some cases with the aid of the computer system 701, can implement a peer-to-peer network, which may enable devices coupled to the computer system 701 to behave as a client or a server.

[0204]

[0150] The CPU 705 can execute a sequence of machine-readable instructions, which can be embodied in a program or software. The instructions may be stored in a memory location, such as the memory 710. The instructions can be directed to the CPU 705, which can subsequently program or otherwise configure the CPU 705 to implement methods of the present disclosure. Examples of operations performed by the CPU 705 can include fetch, decode, execute, and writeback.

[0205]

[0151] The CPU 705 can be part of a circuit, such as an integrated circuit. One or more other components of the system 701 can be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0206]

[0152] The storage unit 715 can store files, such as drivers, libraries and saved programs. The storage unit 715 can store user data, e.g., user preferences and user programs. The computer system 701 in some cases can include one or more additional data storage units that are located external to the computer system 701 (e.g., on a remote server that is in communication with the computer system 701 through an intranet or the Internet).

[0207]

[0153] The computer system 701 can communicate with one or more remote computer systems through the network 730. For instance, the computer system 701 can communicate with a remote computer system of a user (e.g., an operator overseeing or monitoring the capturing of carbon dioxide or energy output, etc.). Examples of remote computer systems include personal computers (e.g., portable PC), slate or tablet PC’s (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones (e.g., Apple® iPhone, Android-enabledAttorney Docket No. 64117-709601

[0208] device, Blackberry®), or personal digital assistants. The user can access the computer system 701 via the network 730.

[0209]

[0154] Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the computer system 701, such as, for example, on the memory 710 or electronic storage unit 715. The machine executable or machine readable code can be provided in the form of software. During use, the code can be executed by the processor 705. In some cases, the code can be retrieved from the storage unit 715 and stored on the memory 710 for ready access by the processor 705. In some situations, the electronic storage unit 715 can be precluded, and machine-executable instructions are stored on memory 710.

[0210]

[0155] The code can be pre-compiled and configured for use with a machine having a processor adapted to execute the code, or can be compiled during runtime. The code can be supplied in a programming language that can be selected to enable the code to execute in a pre-compiled or as-compiled fashion.

[0211]

[0156] Aspects of the systems and methods provided herein, such as the computer system 701, can be embodied in programming. Various aspects of the technology may be thought of as "products" or "articles of manufacture" typically in the form of machine (or processor) executable code and / or associated data that is carried on or embodied in a type of machine readable medium. Machine-executable code can be stored on an electronic storage unit, such as memory (e.g., read-only memory, random-access memory, flash memory) or a hard disk. "Storage" type media can include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from a management server or host computer into the computer platform of an application server. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links or the like, also may be considered as media bearing the software. As used herein, unless restricted to non-transitory, tangible "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructionsAttorney Docket No. 64117-709601

[0212] to a processor for execution.

[0213]

[0157] Hence, a machine readable medium, such as computer-executable code, may take many forms, including but not limited to, a tangible storage medium, a carrier wave medium or physical transmission medium. Non-volatile storage media including, for example, optical or magnetic disks, or any storage devices in any computer(s) or the like, may be used to implement the databases, etc. shown in the drawings. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a ROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and / or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

[0214]

[0158] The computer system 701 can include or be in communication with an electronic display 735 that comprises a user interface (UI) 740 for providing, for example, properties of molten salts, properties of one or more corrosion products, or a thickness of a frozen salt layer. The portal may be provided through an application programming interface (API). A user or entity can also interact with various elements in the portal via the UI. Examples of UI’s include, without limitation, a graphical user interface (GUI) and web-based user interface.

[0215]

[0159] Methods and systems of the present disclosure can be implemented by way of one or more algorithms. An algorithm can be implemented by way of software upon execution by the central processing unit 705. For example, the algorithm may be configured to adjust an operation of the system depending on energy needs (e.g., decrease in energy output or increase in energy output).

[0216]

[0160] While certain embodiments of the present systems and methods have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the systems and methods describedAttorney Docket No. 64117-709601

[0217] herein be limited by the specific examples provided within the specification. The descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the systems and methods described herein.

[0218] Furthermore, it shall be understood that all aspects of the systems and methods described herein are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments described herein may be employed. It is therefore contemplated that the systems and methods described herein shall also cover any such alternatives, modifications, variations or equivalents. It is intended that the following claims define the scope of the systems and methods described herein and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

Attorney Docket No. 64117-709601CLAIMS WHAT IS CLAIMED IS:

1. A system, comprising:a first conduit comprised of a first material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, and wherein the molten salt stream comprises an oxidizing species; anda second conduit comprised of a second material fluidically connected to the first conduit, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature, wherein a first corrosion product is formed in the first conduit, wherein the first corrosion product comprises the oxidizing species and the first material,wherein a second corrosion product is formed in the second conduit, wherein the second corrosion product comprises the oxidizing species and the second material, and wherein a concentration of the second corrosion product is less than or equal to a concentration of the first corrosion product.

2. The system of claim 1, wherein the oxidizing species comprises carbonates, oxides, metal oxides, peroxides, or any combination thereof.

3. The system of claim 1, wherein the first temperature is from about 300 °C to about 700 °C.

4. The system of claim 1, wherein the first temperature is from about 400 °C to about 700 °C.

5. The system of claim 1, wherein the second temperature is from about 500 °C to about 900 °C.

6. The system of claim 1, wherein the second temperature is from about 600 °C to about 900 °C.

7. The system of claim 1, wherein the first material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

8. The system of claim 1, wherein the second material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

9. The system of claim 1, wherein the first conduit further comprises a first coating disposed thereon.Attorney Docket No. 64117-70960110. The system of claim 9, wherein the first coating comprises a nickel, cobalt, carbonbased salt facing layer, or any combination thereof.

11. The system of claim 9, wherein the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

12. The system of claim 1, wherein the second conduit further comprises a second coating disposed thereon.

13. The system of claim 12, wherein the second coating comprises a nickel, cobalt, carbon-based salt facing layer, or any combination thereof.

14. The system of claim 12, wherein the second coating is applied to the second conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

15. The system of claim 1, wherein the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is different than the second coating.

16. The system of claim 1, wherein the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is the same as the second coating.

17. The system of claim 1, wherein the first conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof.

18. The system of claim 1, wherein the second conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof.

19. The system of claim 17 or 18, wherein the alternating species reacts with the oxidizing species preferentially.

20. The system of claim 1, wherein the first material is different from the second material.

21. The system of claim 1, wherein the first material contains less nickel than the second material.

22. The system of claim 21, wherein the first material contains at least about 10% less nickel than the second material.

23. The system of claim 21, wherein the first material contains at least about 20% less nickel than the second material.

24. The system of claim 21, wherein the first material contains at least about 50% less nickel than the second material.Attorney Docket No. 64117-70960125. The system of claim 1, wherein the first material contains less cobalt than the second material.

26. The system of claim 25, wherein the first material contains at least about 10% less cobalt than the second material.

27. The system of claim 25, wherein the first material contains at least about 20% less cobalt than the second material.

28. The system of claim 25, wherein the first material contains at least about 50% less cobalt than the second material.

29. The system of claim 1, wherein the first material contains more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

30. The system of claim 29, wherein the first material contains at least about 50% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

31. The system of claim 29, wherein the first material contains at least about 100% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

32. The system of claim 29, wherein the first material contains at least about 200% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

33. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at least about 1% metal oxides.

34. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at least about 5% metal oxides.

35. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at least about 10% metal oxides.

36. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at least about 20% metal oxides.

37. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at least about 40% metal oxides.

38. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at least about 50% metal oxides.

39. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at most about 1% metal oxides.Attorney Docket No. 64117-70960140. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at most about 5% metal oxides.

41. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at most about 10% metal oxides.

42. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at most about 20% metal oxides.

43. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at most about 40% metal oxides.

44. The system of claim 1, wherein the first corrosion product and / or the second corrosion product comprises at most about 50% metal oxides.

45. The system of claim 1, further comprising a heat exchanger fluidically connected to the first conduit and the second conduit.

46. The system of claim 45, wherein the heat exchanger is configured to cool the molten salt stream from the second temperature to the first temperature.

47. The system of claim 45, wherein the heat exchanger is configured to receive a fluid that is below a melting temperature of the molten salt stream.

48. The system of claim 47, wherein the heat exchanger is configured to transfer heat from the molten salt stream to the fluid.

49. The system of claim 45, wherein the molten salt stream is configured to exit the second conduit, flow through the heat exchanger, and enter the first conduit.

50. The system of claim 45, wherein an interior portion of the heat exchanger wall configured to contact the molten salt stream is configured to be heated using impedance heating.

51. The system of claim 50, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 1 °C below a freezing point of the molten salt stream.

52. The system of claim 50, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 3 °C below a freezing point of the molten salt stream.

53. The system of claim 50, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 5 °C below a freezing point of the molten salt stream.Attorney Docket No. 64117-70960154. The system of claim 50, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 10 °C below a freezing point of the molten salt stream.

55. The system of claim 50, wherein upon application of the impedance heating, a protective salt layer forms on the interior portion of the heat exchanger wall.

56. The system of claim 55, wherein the protective salt layer is at most about 0.01 millimeters.

57. The system of claim 55, wherein the protective salt layer is at most about 0.1 millimeters.

58. The system of claim 50, wherein a current is applied to the interior portion of the heat exchanger wall.

59. The system of claim 58, wherein the current is at least about 0.1 amperes.

60. The system of claim 58, wherein the current is at least about 1 ampere.

61. The system of claim 58, wherein the current is an alternating current (AC).

62. The system of claim 61, wherein a voltage of the AC current is at least about 120 volts.

63. The system of claim 61, wherein a voltage of the AC current is at least about 240 volts.

64. The system of claim 61, wherein a voltage of the AC current is at least about 480 volts.

65. The system of claim 58, wherein the current is a direct current (DC).

66. The system of claim 65, wherein a voltage of the DC current is at least about 5 volts.

67. The system of claim 65, wherein a voltage of the DC current is at least about 10 volts.

68. The system of claim 65, wherein a voltage of the DC current is at least about 50 volts.

69. The system of claim 65, wherein a voltage of the DC current is at least about 100 volts.

70. The system of claim 1, further comprising:an absorber fluidically connected to the first conduit or the second conduit, wherein the absorber is configured to contact the molten salt stream with a gaseous stream comprising CO2, to yield a molten salt stream comprising absorbed CO2.

71. The system of claim 70, further comprising:a desorber fluidically connected to the absorber, wherein the desorber is configured to release the absorbed CO2 from the molten salt stream.Attorney Docket No. 64117-70960172. The system of claim 1, wherein the first conduit or the second conduit is configured to receive carbon monoxide (CO).

73. A method, comprising:(a) providing a first conduit comprised of a first material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, and wherein the molten salt stream comprises an oxidizing species; and(b) providing a second conduit comprised of a second material fluidically connected to the first conduit, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature,wherein a first corrosion product is formed in the first conduit, wherein the first corrosion product comprises the oxidizing species and the first material,wherein a second corrosion product is formed in the second conduit, wherein the second corrosion product comprises the oxidizing species and the second material, and wherein a concentration of the second corrosion product is less than or equal to a concentration of the first corrosion product.

74. The method of claim 73, wherein the oxidizing species comprises carbonates, oxides, metal oxides, peroxides, or any combination thereof.

75. The method of claim 73, wherein the first temperature is from about 300 °C to about 700 °C.

76. The method of claim 73, wherein the first temperature is from about 400 °C to about 700 °C.

77. The method of claim 73, wherein the second temperature is from about 500 °C to about 900 °C.

78. The method of claim 73, wherein the second temperature is from about 600 °C to about 900 °C.

79. The method of claim 73, wherein the first material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

80. The method of claim 73, wherein the second material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

81. The method of claim 73, wherein the first conduit further comprises a first coating disposed thereon.

82. The method of claim 81, wherein the first coating comprises a nickel, cobalt, carbonbased salt facing later, or any combination thereof.Attorney Docket No. 64117-70960183. The method of claim 81, wherein the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

84. The method of claim 73, wherein the second conduit further comprises a second coating disposed thereon.

85. The method of claim 84, wherein the second coating comprises a nickel, cobalt, carbon-based salt facing layer, or any combination thereof.

86. The method of claim 84, wherein the second coating is applied to the second conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

87. The method of claim 73, wherein the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is different than the second coating.

88. The method of claim 73, wherein the first conduit further comprises a first coating disposed thereon, wherein the second conduit further comprises a second coating disposed thereon, and wherein the first coating is the same as the second coating.

89. The method of claim 73, wherein the first conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof.

90. The method of claim 73, wherein the second conduit is configured to receive carbon black, graphite, carbon monoxide, metal oxides, an alternating species, or any combination thereof.

91. The method of claim 89 or 90, wherein the alternating species reacts with the oxidizing species preferentially.

92. The method of claim 73, wherein the first material is different from the second material.

93. The method of claim 73, wherein the first material contains less nickel than the second material.

94. The method of claim 93, wherein the first material contains at least about 10% less nickel than the second material.

95. The method of claim 93, wherein the first material contains at least about 20% less nickel than the second material.

96. The method of claim 93, wherein the first material contains at least about 50% less nickel than the second material.Attorney Docket No. 64117-70960197. The method of claim 73, wherein the first material contains less cobalt than the second material.

98. The method of claim 97, wherein the first material contains at least about 10% less cobalt than the second material.

99. The method of claim 97, wherein the first material contains at least about 20% less cobalt than the second material.

100. The method of claim 97, wherein the first material contains at least about 50% less cobalt than the second material.

101. The method of claim 73, wherein the first material contains more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

102. The method of claim 101, wherein the first material contains at least about 50% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

103. The method of claim 101, wherein the first material contains at least about 100% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

104. The method of claim 101, wherein the first material contains at least about 200% more iron, chromium, manganese, molybdenum, or any combination thereof, than the second material.

105. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at least about 1% metal oxides.

106. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at least about 5% metal oxides.

107. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at least about 10% metal oxides.

108. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at least about 20% metal oxides.

109. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at least about 40% metal oxides.

110. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at least about 50% metal oxides.

111. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at most about 1% metal oxides.Attorney Docket No. 64117-709601112. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at most about 5% metal oxides.

113. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at most about 10% metal oxides.

114. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at most about 20% metal oxides.

115. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at most about 40% metal oxides.

116. The method of claim 73, wherein the first corrosion product and / or the second corrosion product comprises at most about 50% metal oxides.

117. The method of claim 73, further comprising providing a heat exchanger fluidically connected to the first conduit and the second conduit.

118. The method of claim 117, wherein the heat exchanger is configured to cool the molten salt stream from the second temperature to the first temperature.

119. The method of claim 117, wherein the heat exchanger is configured to receive a fluid that is below a melting temperature of the molten salt stream.

120. The method of claim 117, wherein the heat exchanger is configured to transfer heat from the molten salt stream to the fluid.

121. The method of claim 117, wherein the molten salt stream is configured to exit the second conduit, flow through the heat exchanger, and enter the first conduit.

122. The method of claim 117, wherein an interior portion of the heat exchanger wall configured to contact the molten salt stream is heated using impedance heating.

123. The method of claim 122, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 1 °C below a freezing point of the molten salt stream.

124. The method of claim 122, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 3 °C below a freezing point of the molten salt stream.

125. The method of claim 122, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 5 °C below a freezing point of the molten salt stream.

126. The method of claim 122, wherein the impedance heating is configured to raise a temperature of the interior portion of the heat exchanger wall to within about 10 °C below a freezing point of the molten salt stream.Attorney Docket No. 64117-709601127. The method of claim 122, wherein upon application of the impedance heating, a protective salt layer forms on the interior portion of the heat exchanger wall.

128. The method of claim 127, wherein the protective salt layer is at most about 0.01 millimeters.

129. The method of claim 127, wherein the protective salt layer is at most about 0.1 millimeters.

130. The method of claim 74, further comprising applying a current to the first conduit and / or the second conduit.

131. The method of claim 130, wherein the current is at least about 0.1 amperes.

132. The method of claim 130, wherein the current is at least about 1 ampere.

133. The method of claim 130, wherein the current is an alternating current (AC).

134. The method of claim 133, wherein a voltage of the AC current is at least about 120 volts.

135. The method of claim 133, wherein a voltage of the AC current is at least about 240 volts.

136. The method of claim 133, wherein a voltage of the AC current is at least about 480 volts.

137. The method of claim 130, wherein the current is a direct current (DC).

138. The method of claim 137, wherein a voltage of the DC current is at least about 5 volts.

139. The method of claim 137, wherein a voltage of the DC current is at least about 10 volts.

140. The method of claim 137, wherein a voltage of the DC current is at least about 50 volts.

141. The method of claim 137, wherein a voltage of the DC current is at least about 100 volts.

142. The method of claim 73, further comprising introducing carbon monoxide (CO) to the first conduit or the second conduit.

143. The method of claim 73, further comprising:(c) providing an absorber fluidically connected to the first conduit or the second conduit, wherein the absorber is configured to contact the molten salt stream with a gaseous stream comprising CO2, thereby obtaining a molten salt stream comprising absorbed CO2.

144. The method of claim 142, further comprising:Attorney Docket No. 64117-709601(d) providing a desorber fluidically connected to the absorber, wherein the desorber is configured to release the absorbed CO2 from the molten salt stream.

145. The method of claim 144, further comprising, prior to (a), introducing an additional corrosion product to the molten salt stream.

146. The method of claim 145, wherein the additional corrosion product comprises the oxidizing species, carbon monoxide (CO), carbonites, the first material or the second material, or any combination thereof.

147. The method of claim 145, wherein an amount of the additional corrosion product introduced to the molten salt stream is an equilibrium level of the first corrosion product or the second corrosion product.

148. The method of claim 145, wherein an amount of the additional corrosion product introduced to the molten salt stream is at least about 10% of the equilibrium level of the first corrosion product or the second corrosion product.

149. The method of claim 145, wherein an amount of the additional corrosion product introduced to the molten salt stream is at least about 90% of the equilibrium level of the first corrosion product or the second corrosion product.

150. The method of claim 73, further comprising introducing a current to provide electrons to the first conduit and / or the second conduit.

151. The method of claim 150, wherein the electrons interact with the oxidizing species without oxidation of the first material or the second material.

152. The method of claim 150, wherein the electrons are provided by one or more electrical connections located on either end of the first conduit or the second conduit.

153. The method of claim 150, wherein the electrons are provided by one or more electrical connections located underneath the first conduit or the second conduit.

154. A method, comprising:(a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species;(b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature; and(c) introducing carbon monoxide (CO) to the first conduit or the second conduit, wherein introducing the CO to the first conduit or the second conduit reduces an amount ofAttorney Docket No. 64117-709601corrosion product formed in the first conduit or the second conduit, wherein the corrosion product comprises the oxidizing species and the material.

155. The method of claim 154, wherein the oxidizing species comprises carbonates, metal oxides, peroxides, or any combination thereof.

156. The method of claim 154, wherein the first temperature is from about 300 °C to about 700 °C.

157. The method of claim 154, wherein the first temperature is from about 400 °C to about 700 °C.

158. The method of claim 154, wherein the second temperature is from about 500 °C to about 900 °C.

159. The method of claim 154, wherein the second temperature is from about 600 °C to about 900 °C.

160. The method of claim 154, wherein the material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

161. The method of claim 154, wherein the first conduit or the second conduit further comprises a first coating disposed thereon.

162. The method of claim 161, wherein the first coating comprises a nickel, cobalt, carbonbased salt facing later, or any combination thereof.

163. The method of claim 161, wherein the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

164. The method of claim 154, wherein the CO is bubbled through the molten salt stream in the first conduit or the second conduit.

165. The method of claim 154, wherein the CO is introduced into a headspace above the molten salt stream in the first conduit or the second conduit.

166. A method, comprising:(a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species, wherein a corrosion product is formed in the first conduit, and wherein the corrosion product comprises the oxidizing species and the material; and(b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receiveAttorney Docket No. 64117-709601the molten salt stream at a second temperature, wherein the second temperature is greater than the first temperature, wherein the corrosion product is formed in the second conduit, wherein prior to (a) and (b), an additional corrosion product is introduced to the molten salt stream, and wherein the additional corrosion product comprises the oxidizing species and the material, wherein introducing the additional corrosion product to the first conduit or the second conduit reduces an amount of the corrosion product formed in the first conduit or the second conduit.

167. The method of claim 166, wherein the oxidizing species comprises carbonates, metal oxides, peroxides, or any combination thereof.

168. The method of claim 166, wherein the first temperature is from about 300 °C to about 700 °C.

169. The method of claim 166, wherein the first temperature is from about 400 °C to about 700 °C.

170. The method of claim 166, wherein the second temperature is from about 500 °C to about 900 °C.

171. The method of claim 166, wherein the second temperature is from about 600 °C to about 900 °C.

172. The method of claim 166, wherein the material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

173. The method of claim 166, wherein an amount of the additional corrosion product introduced to the molten salt stream is an equilibrium level of the corrosion product.

174. The method of claim 166, wherein an amount of the additional corrosion product introduced to the molten salt stream is at least about 10% of the equilibrium level of the corrosion product.

175. The method of claim 166, wherein an amount of the additional corrosion product introduced to the molten salt stream is at least about 90% of the equilibrium level of the corrosion product.

176. A method, comprising:(a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species;(b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receiveAttorney Docket No. 64117-709601the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature; and(c) applying a current to the first conduit or the second conduit, wherein electrons provided by the current interact with the oxidizing species, thereby reducing an amount of corrosion product formed in the first conduit or the second conduit, wherein the corrosion product comprises the oxidizing species and the material.

177. The method of claim 176, wherein the electrons reduce the oxidizing species without oxidation of the material.

178. The method of claim 176, wherein the first temperature is from about 300 °C to about 700 °C.

179. The method of claim 176, wherein the first temperature is from about 400 °C to about 700 °C.

180. The method of claim 176, wherein the second temperature is from about 500 °C to about 900 °C.

181. The method of claim 176, wherein the second temperature is from about 600 °C to about 900 °C.

182. The method of claim 176, wherein the current is at least about 0.1 amperes.

183. The method of claim 176, wherein the current is at least about 1 ampere.

184. The method of claim 176, wherein the current is an alternating current (AC).

185. The method of claim 184, wherein a voltage of the AC current is at least about 120 volts.

186. The method of claim 184, wherein a voltage of the AC current is at least about 240 volts.

187. The method of claim 184, wherein a voltage of the AC current is at least about 480 volts.

188. The method of claim 176, wherein the current is a direct current (DC).

189. The method of claim 188, wherein a voltage of the DC current is at least about 5 volts.

190. The method of claim 188, wherein a voltage of the DC current is at least about 10 volts.

191. The method of claim 188, wherein a voltage of the DC current is at least about 50 volts.

192. The method of claim 188, wherein a voltage of the DC current is at least about 100 volts.Attorney Docket No. 64117-709601193. A method, comprising:(a) directing a molten salt stream through a first conduit of a heat exchanger; (b) directing a fluid through a second conduit of the heat exchanger, wherein the fluid is at a temperature below a melting point of the molten salt stream; and(c) using impedance heating, raising a temperature of an interior portion of a wall of the heat exchanger that contacts the molten salt stream, thereby controlling a thickness of a frozen salt layer on the interior portion of the wall of the heat exchanger.

194. The method of claim 193, wherein the fluid comprises a different molten salt, water, steam, CO2, or a flue gas, or any combination thereof.

195. The method of claim 193, wherein the heat exchanger is configured to transfer heat from the molten salt stream to the fluid.

196. The method of claim 193, wherein the temperature of the interior portion of the wall of the heat exchanger is raised to about 1 °C below a freezing point of the molten salt stream.

197. The method of claim 193, wherein the temperature of the interior portion of the wall of the heat exchanger is raised to about 3 °C below a freezing point of the molten salt stream.

198. The method of claim 193, wherein the temperature of the interior portion of the wall of the heat exchanger is raised to about 5 °C below a freezing point of the molten salt stream.

199. The method of claim 193, wherein the temperature of the interior portion of the wall of the heat exchanger is raised to about 10 °C below a freezing point of the molten salt stream.

200. The method of claim 193, wherein the thickness of the frozen salt layer is controlled to be at most about 0.01 millimeters.

201. The method of claim 193, wherein the thickness of the frozen salt layer is controlled to be at most about 0.1 millimeters.

202. A method, comprising:(a) providing a first conduit comprised of a material, wherein the first conduit is configured to receive a molten salt stream at a first temperature, wherein the molten salt stream comprises an oxidizing species;(b) providing a second conduit fluidically connected to the first conduit, wherein the second conduit comprises the material, wherein the second conduit is configured to receive the molten salt stream at a second temperature, wherein the second temperature is higher than the first temperature; and(c) introducing a reducing species to the first conduit or the second conduit, wherein introducing the reducing species to the first conduit or the second conduit reduces an amountAttorney Docket No. 64117-709601of corrosion product formed in the first conduit or the second conduit, wherein the corrosion product comprises the oxidizing species and the material.

203. The method of claim 202, wherein the reducing species comprise a sodium metal, a lithium metal, a potassium metal, a beryllium metal, a calcium metal, a chromium, a molybdenum, a carbon, a boron, or any combination thereof.

204. The method of claim 202, wherein introducing the reducing species to the first conduit or the second conduit reduces an adverse effect of the molten salt stream.

205. The method of claim 204, wherein the adverse effect of the molten salt stream is less than about 50% increase in a viscosity of the molten salt stream without introducing the reducing species to the first conduit or the second conduit.

206. The method of claim 204, wherein the adverse effect of the molten salt stream is less than about 50% increase in a melting point of the molten salt stream without introducing the reducing species to the first conduit or the second conduit.

207. The method of claim 202, wherein the oxidizing species comprises carbonates, metal oxides, peroxides, or any combination thereof.

208. The method of claim 202, wherein the first temperature is from about 300 °C to about 700 °C.

209. The method of claim 202, wherein the first temperature is from about 400 °C to about 700 °C.

210. The method of claim 202, wherein the second temperature is from about 500 °C to about 900 °C.

211. The method of claim 202, wherein the second temperature is from about 600 °C to about 900 °C.

212. The method of claim 202, wherein the material comprises carbon based materials, steels, high-nickel alloys, high-cobalt alloys, or any combination thereof.

213. The method of claim 202, wherein the first conduit or the second conduit further comprises a first coating disposed thereon.

214. The method of claim 213, wherein the first coating comprises a nickel, cobalt, carbonbased salt facing later, or any combination thereof.

215. The method of claim 213, wherein the first coating is applied to the first conduit via vapor deposition, electrolytic applications, electroless applications, weld overlays, brushed, dipped, air sprayed, or any combination thereof.

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